Apparatus and method for preparing and presenting serum chemistries for analyzation

Abstract

Apparatus for handling and preparing for analyzation serum chemistries composed of serum specimens and chemical reagents. Serum specimens are loaded into a plurality of specimen cups in a specimen conveyor, and chosen ones of said cups are successively pressurized by a transfer apparatus to a predetermined pressure level. The transfer apparatus has a water-filled pickup tube having one end received in the specimen in a pressurized serum cup, and the other end couplable by a vent valve to atmospheric pressure for a closely controlled time period to allow the pressure within the serum cup to cause flow of a predetermined amount of the specimen into said pickup tube. The transfer apparatus transfers the picked-up specimen to above a chemistry cup in a chemistry conveyor where the other end of the pickup tube is selectively coupled by a pressure valve to a pressurized water supply for a predetermined time period to cause deposition of a predetermined amount of picked-up specimen into the underlying chemistry cup. Each of the reagents is contained in a reagent bottle which is maintained by pressurizing means at a substantially constant pressure level. A delivery tube has one end received in the reagent and the other end couplable by a delivery valve to a position above one of the chemistry cups of the chemistry conveyor. The delivery valve is selectively operable for a predetermined time period to allow deposition of a predetermined amount of reagent into the underlying chemistry cup.

Parent Case Text

This is a continuation application of co-pending application Ser. No. 283,415, filed Aug. 24, 1972, and now abandoned, which was in turn a continuation-in-part of co-pending application Ser. No. 179,013, filed Sept. 9, 1971, and now abandoned.

Description

BACKGROUND OF THE INVENTION

This invention relates to apparatus and a method for preparing and chemically analyzing a serum sample from a specimen of serum, e.g., blood or other body fluid. More specifically, the apparatus comprises means to rapidly and successively present samples of identified serum specimens to individual test tubes; means to automatically and precisely dispense a number of programmed chemical test reagents into these test tubes at programmed intervals; means to incubate the resulting test chemistries for a predetermined period of time at a predetermined temperature; and means to remove, at the proper time, a preselected amount of each of the thereby formulated test chemistries for spectral analysis.

The chemical analysis of a serum, e.g., for the presence of sugar or albumin or in other vital assays to measure other medically-significant factors, is a vital step of medical diagnosis. Testing for various serum constituents is generally performed in a manual or automated process by adding specific amounts of various reactive chemicals or reagents to a sample of serum in a specific sequence and under specified conditions of temperature and time. The color or light transmittance of the resulting test chemistry is related to the amount of the particular constituent being measured in the serum.

In manual procedures, such assays are normally performed in a laboratory by a trained technician. The technician conventionally has used a graduated transfer pipette to place the serum sample to be tested in a test tube, after which he adds, at certain intervals of time, the proper reagents for the specific test. Some tests allow all the reagents, normally up to four or five in number, to be added simultaneously, while others require that predetermined incubation periods take place between the addition of the required reagents. The incubation periods, at times, must be carried out while elevating the temperature of the partially or fully complemented test chemistry so that a required chemical reaction may take place. A discrete amount of the test chemistry is removed by a pipette after all the reagents have been added and the incubation periods, if any, have elapsed. The light transmittance value of this test chemistry can then be ascertained using a conventional spectrophotometer. This value can then be used to calculate the optical density of the chemistry and from which the percentage concentration in the serum of the constituent of interest must be derived.

Disadvantages of such manual methods include undue labor cost and time, and the accuracy of this type of laboratory testing is at most, even under optimum conditions, only proportional to the skill of the technician. Error may be introduced into the test by any one of several ways, such as by adding incorrect amounts of reagent or by not incubating the test chemistry for the proper interval of time at the proper temperature. The inability of even the most skilled technician to prevent changes in thermally and oxidatively labile reagents constitutes an additional and often inevitable source of inaccuracy.

Several automatic systems have been proposed to eliminate the problems and disadvantages inherent in manual testing; and such automated procedures constitute at the present time a large portion of the assays currently conducted. The automated testing devices perform the assay functions automatically, and have attempted to eliminate one or more of the disadvantages of the manual methods. Automated analyzers of the prior art have primarily used two means of automatically dispensing specific amounts of reagents. Whitehead et al., in 1959, (U.S. Pat. No. 2,899,280) described a device in which the reagents are proportioned into the test chemistry and the chemistry transmitted or conveyed by a peristaltic pumping action. The reaction thereby occurs in a flowing stream. The amount or proportion of each reagent which is added is determined by the diameter of the tubes in the peristaltic pump. This has a particular disadvantage in that the tubes must be changed in order to change the proportions or amount of reagents added to a particular test.

Most other automated devices which have been developed use a hydraulic dispensing principle in which a device similar to a syringe displaces a volume of liquid into a reaction vessel. Such a dispensing mechanism was described by Feichtmeir in 1958 (U.S. Pat. No. 3,012,863). Even though such dispensers may be accurate in the amount they dispense, they must be mechanically adjusted to change from one volume of dispensing to another; and it is difficult to cleanse a previously used reagent from them. Both of these steps are required in changing from one test to another.

SUMMARY OF THE INVENTION

In accordance with a preferred embodiment of the invention, an automatic machine is provided which is generally comprised of a serum specimen holder and conveyor, a serum sample transfer station, a test chemistry holder and conveyor, multiple reagent dispensing stations, and an extraction station for transferring a completed test chemistry comprised of serum and reagents to an analyzing apparatus such as a spectrophotometer or a fluorometer for determining the light transmitted by or emitted from the solution.

The serum specimens to be assayed are obtained from patients in a conventional manner. These specimens are placed in individual test cups carried in holes in the top of the serum specimen conveyor. An advantageous feature of this equipment is that the amount of the serum placed in these cups is not critical, for the precise amount needed for a test sample will be extracted from these cups automatically. Degradation of the serum specimens is prevented by cooling means in a channel in the serum specimen conveyor into which the specimen cups project.

The serum specimen cup holes are successively numbered to provide patient identification. There is also an actuator button associated with each of the test cups. The buttons, when displaced to a control position or setting, signify to electronic controlling logic means the particular serum specimens which are to receive the particular serum chemistry test being performed at that time. The utilization of patient identification buttons selectively permit a plurality of assays to be performed on specimens of the same serum specimen.

The particular test and its associated parameters, such as the volume and type of each reagent to be dispensed, the time and temperature of each incubation, if any, and the volume of serum sample required, are presented to the machine by means of a program card which has been specifically prepared for that type of test. The card, once inserted in the machine, serves as the program memory for the electronic control logic section of the machine. Any parameters may be easily changed by punching a new program card.

The testing procedure is completely automatic and requires no operator intervention after the proper patient identification buttons have been displaced and appropriate parameters set. In a preferred embodiment, the specimen conveyor indexes to position the first serum specimen cup located adjacent a displaced patient identification button into a transfer position for transferal of a sample or portion of the serum specimen to a test tube in the test chemistry conveyor. The pick-up portion of the serum transfer apparatus aligns with and descends onto the specimen cup. The specimen cup is pressurized and a precise amount of serum for the test sample thereof is extracted using a controlled orifice technique. The sample apparatus transfers the extracted serum sample to a waiting test tube which is carried in the test chemistry conveyor. If desired, an amount of diluent, such as water, can be added to the serum in the test tube at this time. The tip of the sample extractor is washed and dried as the sample apparatus swings back to pick up the next serum sample.

In position, the transfer apparatus again descends to pick up the sample amount of the next serum specimen which has been indexed to the transfer position. This procedure continues until samples have been extracted from all the cups in the specimen conveyor identified by a displaced patient identification button. The specimen wheel then returns to a home position which is preferably defined as when the specimen cup in the hole designated as position "one" on the specimen conveyor is one cup position removed from the sample transfer position.

Concurrent with the indexing of the specimen conveyor, the test chemistry conveyor indexes the first test tube under a first chemical reagent dispensing head as it indexes to present another empty test tube for deposition of a serum sample by the sample transfer apparatus. This begins the dispensing cycle of the test which may be varied in several ways, all of which are at the option of the programmer and under the control of the electronic logic. The dispensing operation makes use of a pressure-time flow regulation technique permitting the use of single valves as its only moving parts. All of the reagents required for the test in progress may be added simultaneously or each reagent may be added on a different pass of the test tubes beneath the dispensing head. Some reagents require an incubation period after being added to the serum sample so that a desired reaction might take place. If required, an incubation period may be utilized after the addition of each reagent. The programmer also has the ability to heat the test chemistries during an incubation period if the particular reaction requires an elevated temperature. The partially completed test chemistries can be mixed after the addition of each reagent to assure a homogeneous mixture and a completed reaction that will not give an erroneous result when the chemistries are analyzed.

The reagents can be kept in individual bottles under pressure desirably supplied by an inert gas, e.g., nitrogen. Any reagents requiring sub-ambient temperatures can be refrigerated. The valves which select the programmed reagents can be flushed with diluent after each set of test reagents has been used, thereby preventing cross-contamination of reagents, and can be purged with the particular set of test reagents at the beginning of a test to prevent any dilution of reagents used in the test by residual diluent.

At the completion of the formulation phase, the test chemistry conveyor indexes the first test tube containing a now-completed test chemistry beneath a test extractor head. After the required amount of test chemistry has been taken from each test tube, the test tube and its remnant chemistries are dropped into a waste container for removal. The displaced patient-identification buttons can then be reset.

This instrument is capable of performing both end point reaction tests and kinetic tests, as required in various types of assays. There are a great number of variables in the kinetic test which must be closely controlled, the two most important being time and temperature. The temperature of the chemistry may be specified by the programmer. Physically, the precise temperature may be achieved by immersing the test chemistries in a controlled temperature and recirculating fluid.

The subsequent analysis of the test chemistries can be carried out using a spectrophotometer or a fluorometer. The spectrophotometer or fluorometer output signals can then be electronically processed to obtain more usable data.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention and, by way of example, show a preferred embodiment of the invention. In such drawings:

FIG. 1 is a perspective view of a machine embodying the invention;

FIG. 2 is a plan view showing a portion of the specimen and test conveyor and the apparatus located therebetween;

FIG. 3 is a horizontal section of the specimen conveyor;

FIG. 4 is a vertical section taken along the line 4--4 of FIG. 3;

FIG. 5 is a diagrammatic representation showing the specimen conveyor cooling channel;

FIG. 6 is a diagrammatic showing of a driving cam for the specimen and test chemistry conveyors;

FIG. 7 is a vertical view, in partial section, of a portion of the sample transfer apparatus;

FIG. 8 is a vertical section taken along the line 8--8 of FIG. 7;

FIG. 9 is a vertical section showing the serum pickup valve apparatus used in conjunction with the transfer apparatus of FIG. 7;

FIG. 10 is a horizontal section of the test conveyor;

FIG. 11 is a sectional view taken along line 11--11 of FIG. 10;

FIG. 12 is a vertical section of a combined dispensing and mixing head;

FIG. 13 is a plan view of a reagent selector apparatus and associated dispensing valves;

FIG. 14 is a vertical section along line 14--14 of FIG. 13;

FIG. 15 is a vertical section along line 15--15 of FIG. 13;

FIG. 16 is a diagrammatic representation of the temperature control apparatus for the test chemistry conveyor;

FIG. 17 is a vertical section, partially diagrammatic, of the test chemistry extraction apparatus and spectrophotometer flow cell;

FIG. 18 is a vertical section of the spectrophotometer flow cell reciprocating apparatus;

FIG. 19 is a vertical view, partially in section, of an alternate embodiment of the sample transfer apparatus;

FIG. 20 is a side view, partially in section, of an alternate embodiment of the serum pickup valve apparatus;

FIG. 21 is an enlarged section of the orificing tube assembly utilized in the valve apparatus of FIG. 20;

FIG. 22 is a vertical view, in section, of an alternate embodiment of the combined dispensing and mixing head;

FIG. 23 is a plan view, partially in section, of an alternate embodiment of the reagent selection apparatus and dispensing valves;

FIG. 24 is a side view, partially in section, of the apparatus valves shown in FIG. 23;

FIG. 25 is a section of one of the valving units shown in FIG. 23, with portions thereof broken away; and

FIG. 26 is a vertical section of an alternative embodiment of the test chemistry extraction apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The chemical analyzation machine shown in the drawings is for the serial analyzation of serum specimens which have been obtained from respective patients by conventional means. The term "serum" is used herein in the sense of representing any animal fluid. The electronic logic control which controls the operation of this machine is shown and described in a co-pending application, U.S. Ser. No. 179,133, now abandoned.

The machine shown in FIG. 1, and which is a preferred embodiment of the invention, comprises an upper housing 10 supported on a lower housing 12 by a post 14. A serum specimen conveying wheel 16 and a test chemistry conveying wheel 18 are supported in and by the top of the lower housing 12. The drive motor for these wheels is located within the lower housing 12. The bottom portion of the lower housing 12 encloses an array of pressurized bottles 20, some of which are enclosed in a refrigerated compartment 22. These bottles 20 contain the various chemical reagents used in the performance of a serum analysis by the machine. They are desirably pressurized with inert nitrogen gas to prevent degradation of the reagents. Dark transparent doors 23 on the front of the lower housing 12 permit the bottle compartment to be observed, while reducing reagent degradation due to light.

A serum transfer apparatus 24, a plurality of dispensing heads 26, 27 and 28, and a test chemistry extraction head 29 are, as shown in FIG. 3, located in close proximity to the serum specimen wheel 16 and the test chemistry wheel 18.

Serum specimens, from which samples are taken during the analysis procedure for test samples, are placed in a plurality of specimen cups 30 which are carried in equally-spaced cavities 31 in the top of the specimen conveying wheel 16. Each of the cavities is numbered and has a patient-identification selection switch 108 associated with it. In a similar manner, test tubes 33 are carried in equally-spaced peripheral holes 34 in the test chemistry conveying wheel 18.

In operation, a serum sample in a position 126 to be transferred, is appropriately taken from its specimen cup 30 in the specimen wheel 16 and transferred to a test tube 33 waiting in a transfer position 127 in the test wheel 18, by the serum sample transfer apparatus 24. The portion of the sample transfer apparatus 24 which transfers the sample can be washed by jets of air and water as it passes over a basin-like cavity 296 on its return trip to the sample wheel 16.

Properly selected reagents are added by means of the dispensing heads 26, 27 and 28 to each of the serum samples which have been transferred to test tubes 33 as the test wheel 18 is indexed through the dispensing stations. The test chemistries thereby formulated are then serially extracted for subsequent optical analyzation, as in a spectrophotometer or fluorometer, by the test chemistry extraction head 29. The spectrophotometer or fluorometer may be housed within the supporting post 14.

The electronic logic control circuitry for controlling each of the operations is contained in the upper housing 10. This circuitry may be programmed by a specially prepared card which is inserted in a slot 36 leading to a card reader (not shown), also supported in and by the upper housing 10. An array of actuation buttons 38 may be located adjacent the card reader slot 36 for manually controlling a part or all of the machine operations. Electronic circuitry, which may also be located in the upper housing 10, can be used to convert the output signals from the spectrophotometer or like device into more usable forms of data such as international enzyme units or milligram percentage concentrations by automatically comparing the spectrophotometer output from the test chemistry with the output from a standard solution whose concentration is known.

The serum specimen wheel 16 is shown in FIGS. 3 through 6 and is comprised of a stationary lower base plate 50 and a rotating top disk 52. The specimen vials, or cups 30, are placed in holes 31 located adjacent to the outer edge of the rotating top disk 52 of the specimen wheel 16. Each of the cups 30 is retained in its receiving cavity 31 by a lip 56 around its upper edge. The cups 30 extend through the top supporting disk 52 and into a channel 58 formed by a circular channel member 60 which is fastened to the base plate 50 of the specimen wheel 16.

The serum specimens in the cups 30 are advantageously cooled as they travel within the specimen wheel channel 58 by cool air which is forced into the channel 58 from the refrigeration compartment 22. As shown in FIG. 5, the cool air is forced through an inlet 62 into an entrance channel 64. This channel 64 opens into the cup channel 58, so that part of the air goes in a clockwise direction and part of the air goes in a counterclockwise direction. The air proceeds for 180.degree. in both directions and leaves the channel 58 by an outlet port 66.

The cup-carrying top disk 52 is rotatably driven by a driving pin plate 68 connected to its lower surface as by pins 70. The plate 68 is also attached to a central shaft 72 which is mounted in bearing blocks 74 and 76 in a cylindrical supporting member 78 connected to and extending from the base plate 50. The lower end of the shaft 72 is supported in a hub 80 by a thrust washer 82 and is held in place by a nut 84.

The driving pin plate 68 is driven by a barrel cam 86. This cam 86 is mounted on a shaft 88 which is supported in a bearing block 90 which is mounted in a supporting bracket 92 that is fastened to the base plate 50 of the specimen wheel 16. The cam driving shaft 88 is driven through a conventional one-half turn clutch 94 from a drive pulley 96 which turns a pulley gear 102 mounted on the clutch 94. The pulley 96 is driven from a motor 98 which drives a second pulley gear 100 on which the drive pulley 96 is mounted.

A solenoid (not shown) is energized to engage the clutch 94 and permit the cam drive shaft 88 to rotate. This solenoid may be de-energized once the clutch has begun to rotate to effect only a 180.degree. rotation of the shaft 88 and cam 86. The shaft 88 and cam 86 may be rotated indefinitely if the solenoid is held in a continuously energized state.

The configuration of the two sets of tracks in the cam 86 is shown in FIG. 6. A 180.degree. rotation of the cam corresponds to the advancement of one cup position by each of the serum cups 30. Preferably, the cup-carrying disk 52 will have a capacity of one hundred serum cups, and thus the advancing of the equally-spaced cups 30 by one cup position means that the wheel 16 has been moved through an angle of 3.6.degree..

The driving pin plate 68 has a driving pin 106 for each of the test cup holes 54. The double lead in the barrel cam 86 allows two such pins to be in communication with the barrel cam even though only one pin is driven at a time. The barrel cam is rotatably driving the pin-driving plate 68 during only a fraction of its total revolution due to the configuration of the barrel cam 86. This places the control of the indexing step with the barrel cam 86, rather than making it dependent upon the accuracy of the one-half turn clutch 94. This independence of control avoids any problems with an accumulated positioning error which may be incurred by the clutch 94.

In operation, a serum specimen from each patient to be tested is placed in one of the serum cups 30. Normally, each of the serum specimens will not be meant to receive all of the tests which may be performed in a series of tests. For example, perhaps only the specimens in cups "2", "5", and "10" are to receive an albumin test, but possibly all the specimens in the specimen wheel 16 are to receive a subsequent test for cholesterol content. The selection of the particular serum specimens which are to receive a particular test is made by the respective patient-identification slide switches 108 which are associated with each of the serum cups 30. In the above example, the switches 108 adjacent cups "2", "5", and "10" would be displaced, i.e., moved to a control position, prior to the albumin test to signify that the serum in those cups is to receive a test for albumin content. At the conclusion of the albumin test, the patient-identification switches 108 associated with all of the serum specimens would be displaced for the cholesterol content test.

A test start button 109 on the front of the machine (FIG. 1) is pressed to initiate a testing cycle after the program card has been inserted and the proper patient-identification buttons 108 corresponding to the serum samples which are to receive that particular test have been displaced. At that time, the clutch solenoid is energized to begin the rotation of the driving cam 86. The one-half turn clutch 94 continues to be engaged until a displaced patient-identification button 108 is detected by a sensing device 110 beneath the rotating disk 52. The sensing device 110 comprises an L-shaped member 112 which is connected to a spring loaded deflection arm 114. The arm 114 is moved to compress a spring 116 when the L-shaped member 112 is deflected by a patient-identification button 108 which has been pushed to a displaced, control position.

The movement of the arm 114 also positions an aperture 118 in an otherwise optically black plate 120 between a light source 122 and a photocell 124. The resulting electrical signal from the photocell 124 is detected by the control logic which de-energizes the clutch solenoid (not shown) and thereby halts the rotation of the pin-driving cam 86. The patient-identification detection device 110 is located so that a depressed button 108 is detected as the corresponding serum cup enters the transfer station 126. This station or cup position 126 is defined as being one cup position removed from the home position 129 of the number one cup which is adjacent the sample or serum transfer apparatus 24.

A flat strobe disk 128, with two diametrically opposed holes 130 and 131 therein, is connected to, and rotates with, the cam shaft 88. A light source 132 and a photocell 134 are positioned such that each time the disk 128 rotates 180.degree. one of the holes 130 or 131 permits a pulse of light to fall on the photocell 134. The electrical pulse generated by the photocell 134 is stored in the electronic logic section and permits the particular serum cup 30 in the transfer station 126 to be identified at any time. The signal from the photocell 124 in the patient-identification button detection device 110 is also stored in the electronic logic section as a means of identifying the particular serum specimens which were sampled.

The stopping of a specimen cup 30 in the transfer position 126 initiates the movement and operation of the serum pickup and transfer apparatus 24. This apparatus 24, one embodiment of which is shown in detail in FIGS. 7 through 9, is supported in, and projects vertically from, the top of the lower machine housing 12. The portion of the transfer mechanism 24 which is located above the level of the test wheel 18 is comprised, in general, of a horizontal swingable arm 140 which is supported on a shaft 142. The shaft 142 is enclosed by a tubular support member 144 which is fastened to the underside of the top 147 of the lower housing 12 by a flange 146 on its lower end.

The enclosed shaft 142 is connected to a spline shaft 148 within the tubular support 144. The spline shaft 148 is connected at its lower end to a coupling block 150 for coupling the piston shaft 152 of an air cylinder 154 to the spline shaft 148. This cylinder 154 is supplied with a pressurized gas for purposes of pneumatic actuation. This is referred to herein as an "air cylinder" even though this embodiment conveniently uses compressed nitrogen which is available from the supply for the pressurization of the reagent bottles 20. All the remaining air cylinders in the system also utilize this supply.

The piston shaft 152 extends through a spring extension plate 156 and through a bottom supporting bracket 158 before entering the air cylinder 154. The shaft 152 is attached at its lower end, within the cylinder 154, to a rollable membrance or diaphragm 160. The diaphragm 160 separates the air cylinder 154 into an inlet section 162 and an exhaust section 164 and seals the one from the other.

Air or other gas as referred to above, is applied, under pressure, to the inlet section 162 through an inlet port 166 to cause the diaphragm 160 to roll downwardly into the solid line position shown in FIG. 7. Correspondingly, the piston shaft 152 is moved downward due to its fixed connection to the diaphragm 160. The downward movement of the piston shaft 152 is transferred by the coupling block 150 to the spline shaft 148 and to the spring extension plate 156 which the coupling block 150 contacts as it moves downward.

Two springs 168 and 170 are each connected at their lower end to the spring extension plate 156. The springs 168 and 170 are respectively supported on and encompass a shaft 172 and 174 which passes through the extension plate 156 and is mounted in the bottom supporting bracket 158. The upper ends of the springs 168 and 170 are connected to end plates 176 and 178 which are mounted on the ends of the shafts 172 and 174. The springs 168 and 170 are extended by the downward movement of the extension plate 156 and oppose this movement.

The spline shaft 148 may be rotatably driven, concurrently with its up and down movement, from a servo stepping motor 180 by wear resistant pulley bands 194 and 196 which are connected to a spline nut 184 on the shaft 148. The spline nut 184 is mounted by means of bearings 186 and 188 in a nut housing 190 which is mounted on a side bracket 192.

Positive rotary drive is supplied to the spline nut 184 by the pulley bands 194 and 196 from a motor-driven pulley 198 around which the bands 194 and 196 pass. The shaft 200 for this pulley 198 is mounted in a bearing block 202 at is upper end. Its lower end is reduced in diameter and is supported in, and extends through, another bearing block 204 and a bracket 206 which supports the pulley 198. This bracket 206 is mounted on the lower side of the top 147 of the lower machine housing 12. The pulley shaft 200 is terminated in a shock absorbing coupling 208, and is connected thereby to the servo stepping motor 180.

An optical position detection disk 210 is mounted on the shock coupling 208 concentrically with the pulley shaft 200. This disk 210 has two holes through it at diametrically opposed locations. The holes are positioned such that one of them is between a light source 212 and a photocell 214 when the horizontal serum transfer arm 140 is above the test chemistry wheel 18 and the other when the arm 140 is above the specimen wheel 16. The resulting electrical signal from the photocell 214 is used to synchronize the up and down motion of the transfer apparatus with the dispensing and pick up of a serum sample.

The band drive system for the spline nut 184 is shown in somewhat more detail in FIG. 8. The pulley bands 194 are preferably comprised of a material with extreme longevity, e.g., a composition of beryllium and copper. One end of each of the bands 194 and 196 is attached to the spline nut 184 and passes around the motor pulley 198 before being attached to a spring-loaded tensioning device 216. The spanning length of each of the bands, from the spline nut 184 to the motor pulley 198, can be interrupted by a second tensioning device 218. Where appropriate, the second tensioning device 218 can be omitted.

The tensioning devices 216 and 218 comprise a spring 220 which is compressed by retaining shoulders 222 and 224. These shoulders 222 and 224 form part of connecting tabs 225 to which the ends of the bands 194 and 196 are connected. The single-ended tensioning device 216 has one end fixedly connected to the frame of the apparatus.

As shown in FIG. 2, the position for the horizontal transfer arm 140 at the beginning of a serum testing procedure, is above the test chemistry wheel 18. Movement of the arm 140 from this position is initiated by a signal from the patient-identification switch detection photocell 124 beneath the specimen wheel 16 signifying that a serum cup 30 containing a serum specimen to be tested, has arrived at the transfer position 126. At this time, the electronic logic control begins pulsing the servo stepping motor 180. The motor 180 turns the motor pulley 198 through the shock absorbing coupling 208, which in turn begins rotating the spline nut 184 by means of the driving bands 194 and 196. The tensioning devices 216 and 218 controlling the bands 194 and 196 absorb the pulsing characteristic of the stepping motor 180 so that the spline nut 194 is smoothly rotated.

One of the holes on the optical transfer arm position detection disk 210 is positioned, as hereinbefore explained, between a light source 212 and a photocell 214 as the horizontal transfer arm 140 finishes its 180.degree. swing to position itself above the specimen cup 30 in the transfer position 126. The resulting electrical pulse from the photocell 214 opens a pressurization valve 221 leading from the pressurized air supply to the inlet port 166 of the up and down air cylinder 154. The resulting gas pressure in the inlet section 162 of the cylinder 154 causes the diaphragm 160 to move downward taking the piston shaft 152 with it. The rolling action of the diaphragm 160 eliminates the need for any breakaway force, so the motion of the shaft 152 is initially and continually smooth.

The coupling block 150 associated with the piston shaft 152 is thereby forced downward onto the spring extension plate 156 as it simultaneously moves the spline shaft 148 downward. The spline shaft 148 is able to move downward by means of ball bearings within the spline nut 184. The movement of the spline shaft 148 causes the horizontal arm 140 to move downward also. This downward travel of the arm 140 continues until a resilient and compressible stopper 222, which protrudes from the lower side of the arm 140, firmly seals itself against the top of a waiting serum cup 30.

A bracket 226 is connected to the spring extension plate 156 on the air cylinder piston shaft 152 and moves up and down with this shaft. Two vertical position optical detection arms 228 and 230 are connected to this bracket 226 and move up and down therewith. Each of these arms 228 and 230 has a hole through it which provides a light path from a light source to a photocell when the arm is in the appropriate position. The upper arm 228 has its hole in communication with a photocell 232 and a light source 234 when the horizontal transfer arm 140 is in its upper-most vertical position. The hole in the lower arm 230 is in communication with a light source 236 and a photocell (not shown) when the horizontal transfer arm 140 is in its lower-most vertical position, i.e., when the resilient stopper 222 has sealed a sample cup 30.

The extraction of the required amount of a serum sample is initiated, by apparatus shown in detail in FIGS. 7 and 9, when the lower of the position photocells referred to above has an electrical output signifying that a serum cup 30 has been sealed by the transfer arm stopper 222. Two small diameter stainless steel tubes 240 and 242 extend from within the horizontal arm 140 and protrude through the resilient end stopper 222. These stainless steel tubes 240 and 242 are inserted at their upper end into the ends of flexible tubes 244 and 246 which extend through the hollow interior of the horizontal arm 140 and into and through the hollow of the supporting shaft 142, the hollow of the spline shaft 148 and the hollow of the air cylinder piston shaft 152, before exiting through the bottom of the air cylinder 154. A loop (not shown) is formed in the two tubes within the housing 12 to provide the take-up and dispensing of the excess tubing as the sample transfer arm 140 is raised and lowered.

The lower end of the flexible tube 244 which is connected to the shorter stainless steel tube 242 in the stopper 222 is connected to the outlet of a pressurization valve (not shown). The inlet of this valve is connected to the pressurized air supply, preferably maintained at a pressure of approximately 10 psi. The lower end of the other flexible tube 246, coupled to the longer stainless steel tube 240 in the stopper 222, is connected to a valve assembly 250 by inserting the tube into a tubular supporting member 252 which contains a glass capillary tube 254 which projects up into the tube 246. A tapered and threaded locking member 256 is then tightened about a similarly tapered member 258 causing the latter to tighten about the inserted flexible tube 246 and form an air-tight seal.

The glass capillary tube 254 extends down into the main valve block 260 and terminates in a perpendicular intersection with a second glass tube 262. Each side of this intersecting glass tube 262 is enlarged in diameter a short distance from its intersection with the vertical tube 254. Within each of these enlarged diameter tubes 264 and 266 is a piston-operated valve plunger 268 and 270. Each of these plungers 268 and 270 is terminated at its forward end by a small resilient washer 272 and 274, respectively, which firmly seats itself against the constricted passageway 262 at the respective end to seal that end from the passageway.

The movement of each of these valving members 268 and 270 is controlled, respectively, by a piston 273 and 275. The pistons 273 and 275 and 274 are rapidly moved by respective solenoids 280 and 282. Each of the piston arms 276 and 278 is supported within the valve block 260 by O-rings 284 and 286 which not only prevent leakage from the valve block but help guide the piston arms 276 and 278 and prevent them from being skewed within their passageways.

Vertical passages 288 and 290 intersect and open into each of the valved passages 264 and 266 just behind each of the valve plungers 268 and 270. These vertical passages 288 and 290 communicate with the narrow cross passage 262 and thereby with the vertical orificed capillary tube 254 when the appropriate valving member 268 and 270 is in its retracted position. One of these vertical passages 288 is connected by a connector 292 in the valve block 260 to a waste receptacle (not shown). The other vertical passage 290 is connected by a similar connector 294 in the valve block 260 to a pressurized water supply which is preferably maintained at a pressure of approximately 10 pounds per square inch.

In operation, and at the beginning of the sample pass i.e., the pass of the specimen wheel 16 through the transfer position 126, both of the solenoid piston arms 276 and 278 are in their extended position, thereby closing off the respective passages 288 and 290. The transfer arm 140 has been rotated and has descended, seating the resilient stopper 222 on the waiting specimen cup 224. The descent and final positioning of the transfer arm 140 positions the hole in the lower optical position arm 230 between the light source 236 and the corresponding photocell. The resulting electrical pulse from the photocell opens the pressurization valve leading from the pressurized gas or air supply to the short tube 242 in the resilient stopper 222. The resulting flow of gas pressurizes the contents of the cup 30.

Shortly after the electronic logic detects the presence of an output from the lower position photocell 236, the logic energizes the sample pickup solenoid 280 which withdraws its connected valving member 268. This withdrawal places the passage 288 leading to the waste receptacle in communication with the long stainless steel tube 240 which has its end submerged in the serum sample in the serum cup 30. The pressure in the cup 30 induces and sustains a flow of serum into this tube 240 as long as the pick-up solenoid 280 is energized. This pickup solenoid 280 is de-energized and re-extends its valving member 268 when the programmed amount of serum has been extracted from the specimen cup 30. The steel extraction tube 240 and the supply tube 246 to which it is connected is initially filled with water, as will hereinafter be described, so that this water is displaced into the waste receptacle when the amount of serum enters the tube 240 under the applied pressure. The serum never reaches the vertical orificed capillary tube 254, thereby allowing all orificing to be done on water.

The signal from the control logic which de-energizes the pick-up solenoid 280 and terminates the extraction of the serum sample also de-energizes the pressurization air valve connected to the short tube 242 and allows the built-up pressure to vent into the atmosphere. The air valve 221 which has been supplying the air cylinder 154 to hold the transfer arm 140 down and the resilient stopper 222 on the sample cup 30 is subsequently de-energized. The two extension springs 168 and 170 acting on the extension plate 156 are then no longer maintained in their extended position by air pressure, so they cause the plate 156 to move upwards, thereby forcing the coupling block 150 and spline shaft 148 to move upward also. The upward movement is buffered to some extent by the air or gas in the inlet chamber 162 of the air cylinder 154 as it is then compressed by the upward moving diaphragm 160 to slowly escape through inlet 166. It can be seen that this upward movement also moves the hole in the position detection arm 230 out of communication with its light source 236 and associated photocell so that the photocell no longer conducts.

The electronic logic notes the absence of this photocell output and once again begins pulsing the servo stepping motor 180 to rotate the transfer arm 140 through 180.degree., back to its position above the test chemistry wheel. The first rotary motion of the stepping motor coupling 208 rotates the optical position detection disc 210 on the stepping motor shaft coupling 208 so that the specimen wheel position detection hole is no longer in communication with its light source 212 and photocell 214. The elimination of this photocell 214 output may be used to close the pressurization valve connected to the short tube 242, as the pressure in the specimen cup is no longer needed.

The horizontal transfer arm 140 is rotated back to the test chemistry wheel position 127 at a rate which slowly increases and then decreases before coming to a rest above that wheel 18. This acceleration and deceleration is controlled from the control logic by the rate at which the control logic pulses the servo stepping motor 180. The varying rate is used so that not even a minute part of the carried serum sample will be slung from the extraction tube 240 due to abrupt stopping or starting of the rotation.

The positioning of the transfer arm 140 into its position above the test wheel 18 brings the test wheel position hole on the optical position detection disk 210 into communication with the light source 212 and photocell 214. The resulting photocell output signals the logic circuitry which ceases to pulse the servo stepping motor 180 and initiates the expulsion of the required amount of serum sample from the steel extraction tube 240. This is done by energizing the transfer solenoid 282 which retracts its piston arm 278 and valving member 270 in the valve block 260. The retraction permits pressurized water from the pressurized supply to enter the valve block 260 through the connector 294 and vertical passage 290 and communicate with the lower end of the tube 246 containing the test sample of serum. This in-flowing forces the serum out the pick-up tube 240 into a test tube 33. The time for which the solenoid 282 is energized is closely controlled, thereby expelling the required amount of serum into the waiting test tube 33 using the pressurized water.

Preferably, an amount of serum was initially extracted from the sample cup 30 in the sample wheel 16 slightly in excess of that which was required for the test to be performed. This insures that the required amount of serum will be deposited in the test tube without any unwanted water which might dilute the serum and affect the test. Water may, however, be desired and is added accordingly.

The logic signal which terminates the expulsion of the required amount of serum sample into the test tube may also be used to initiate the solenoid for the one-half turn clutch 94 in the specimen wheel 16 drive so that the next serum specimen to be tested may be indexed into the transfer position 126 by the specimen wheel. The presence of such a specimen is again detected by the patient-identification detection device 110 which, by means of its photocell 124, initiates a second swing of the transfer arm 140 to pickup another sample from a waiting cup 30. As the horizontal transfer arm 140 makes the second, and all subsequent 180.degree. traverses from the test chemistry wheel 18 to the specimen wheel 16, the transfer solenoid 282 is turned on to purge the extraction tube 240 of any serum sample remaining from the previous sample pickup, to thoroughly wash the tube 240 to prevent any cross-contamination between the serum samples and to fill the tube 240 with water to be displaced during the first or next pick-up. This purging of the extraction tube 240 occurs over a receptacle 296 in the top of the lower housing 12 beneath the swinging arc of the transfer arm 140.

An alternative embodiment of the serum pickup and transfer apparatus 24 is illustrated in FIGS. 19 through 21. In this embodiment, the up and down movement of the spline shaft 148 is effected by an air cylinder 600. The piston shaft 601 of the air cylinder 600 is coupled, by a short shaft 602 which is secured in a mating block 604, to a flexible coupling 606. The output shaft 608 from the coupling 606 is secured to the lower end of the spline shaft 148. The flexible coupling 606 effects the transfer of the up and down motion of the air cylinder 600 to the spline shaft 148, yet isolates the rotation of the spline shaft 148 from the lower mating block 604 and cylinder piston shaft 602.

In this instance, the mating block 604 serves two functions. A vertical rod 610 is connected as by a nut 612 to the underside of the mating block 604 and extends downwardly into and through a hollow sleeve 614 in the lower bracket 158. The rod 610 provides a vertical guide for the up and down movement of the mating block 604 and the lower end of the spline shaft 148. Limiting nuts 616 are threaded on the lower end of the vertical guiding rod 610 to define the uppermost limit to which the horizontal arm 140 can rise.

The mating block 604 is also used as a supporting means for the vertical position detection arm bracket 226, as explained with respect to FIG. 7. Actuation of the air cylinder 600 is initiated by the pressurization valve 221 which is coupled to the inlet port 618 of the cylinder 600. As before, opening this valve 221 allows activating air, under pressure, to communicate with the inlet port 618 of the cylinder 600 to effect the downward movement of the spline shaft 148. Closing this valve 221 allows a return spring (not shown), within the cylinder 600, to return the spline shaft and the piston shaft 602 to their uppermost position.

As before, the extraction of the required amount of a serum sample is initiated when the lower of the positioned photocells has an electrical output signifying that a serum cup 30 has been sealed by a stopper 620 in the transfer arm 140. In the embodiment shown in FIG. 19, a pressurization tube 622 has the pickup tube 624 disposed concentrically therein with sufficient space about the periphery of the pickup tube 624 to afford an adequate discharge annulus for the pressurizing air. These two concentric tubes 622 and 624 are vertically secured by means of a two part threaded fastener 626 which carries the stopper 620 at its lower end. The concentric tubes 622 and 624 extend out of the top of the horizontal arm 140 and re-enter the arm to pass through the hollow in the center of the spline shaft 148 before exiting at the lower end of the spline shaft through an outlet cavity 628 in the wall of the spline shaft 148.

A second stainless steel tube 630 extends vertically through the horizontal arm 140 and has its lower end directed at the pickup tube 624. The tube is held in place by a threaded fastener 632 which also serves to mate the tube with a more flexible tube 634 which, like the two concentric tubes 622 and 624, passes through the interior hollow of the spline shaft 148 and exits through the exit cavity 628. As will be seen, the directed tube 630 is used to clean residual serum sample from the external surface of the pickup tube 624 during the transfer process. This cleansing operation will be described in more detail with respect to the operation of the alternate embodiment of the valve assembly shown in FIG. 9.

The alternate valve assembly 635, shown in FIG. 20 and 21, utilizes a single solenoid driver 636 for effecting the requisite valving action. The lower end of the concentric pickup and pressurization tubes 622 and 624 are coupled to a tee-section 638 within which the outer tube, i.e., the pressurization tube 622, is intersected by an input tube section 640 which supplies the input air needed to this tube 622. The pressurization tube 622, within the tee-section 638, is then blocked off immediately after the intersection of the input tube 640. Accordingly, only the pickup tube 624 is coupled between the tee-section 638 input 642 and the output of the valve assembly 635.

The input tube 640 to the pressurization tube 622 is coupled to the output of the three valves 644, 646 and 648. The first of these valves 644 is, in effect, a venting valve which is opened to release the pressure on the specimen cup to the atmosphere after a sample has been picked up. The second of these valves 646 couples a high pressure air supply 647 to the pressurization tube 622 when it is open. This high pressure air is used, as will be hereinafter more adequately explained, to wipe the outside of the pickup tube 624 during a purging procedure.

The third valve 648 is opened to connect a pressurizing air supply 649, preferably at 10 psi, to the pressurization tube 622 when a serum cup has been sealed by the downward movement of the horizontal arm 140.

The valve body 650 for the serum-pickup valve assembly 635 is coupled to the input end 642 of the tee-section 638 by an orificing tube assembly shown in detail in FIG. 21. The serum pickup tube 624, between the tee-section 638 and the valve body 650 is secured in a short length of stainless steel tubing 652 which is secured in communication with the serum pickup port 656 of the valve body 650 as by a tapered and threaded sealing connector 658. The length of stainless steel tubing 652 can be appropriately crimped as at 660 and 662 to provide the necessary size of orifice for precise serum pickup.

As previously mentioned, the valving action of the serum pickup valve 635 is effected by a single solenoid driver 636 mounted in one end of a valve body supporting block 663. The output shaft 664 of the driver 636 is secured to a valve shaft 666 by a coupling 668. The valve shaft 666 extends into the valve body 650, through a waste passage 670, a resilient sealing member 672 and into an internal valving chamber 674. A valve plunger 676 is secured to the end of the valve rod 666 in this chamber 674. The plunger 676 is formed with generally spherically shaped ends 678 and 680.

The valve chamber 674 has three passages 682, 684 and 686 in communication therewith. The first of these passages 682 is connected by a coupling 688 to a valve 690 whose other side runs to a waste receptacle (not shown).

The second inlet passage 684 extends from the valve chamber 674 through a second resilient member 692, through the valve body 650 and into the threaded coupling 658 linking the serum pickup tube 624 with the valve body 650. The third passage 686, like the first passage 682, is connected by an inlet coupling 694 to a valve 696 which, when open, ports water under pressure from a pressurized supply (not shown) to the third passage 686.

In operation, the horizontal transfer arm 140 is positioned above the serum cup 30 in the sample wheel 16 which is in the transfer position 126. The air cylinder 600 causes the spline shaft 148 to move downward thereby sealing the sample cup 30 with the resilient stopper 620 carried in the horizontal arm 140. At that time, the pressurization valve 648 is opened to admit pressurizing air to the pressurizing tube 622. After a sufficient time delay to allow the pressurization of the serum cup 30, the solenoid driver 636 in the serum pickup valve 635 is appropriately energized to retract the valve rod 666 and cause the valving member 676 to seal against the left resilient member 672. This action places the serum pickup passage 684 in communication with the valve chamber 674. Concurrently with this, the waste valve 690 is opened thereby also allowing the valve chamber 674 to also communicate with the waste receptacle. The serum in the cup 30, being under pressure, enters the serum pickup tube 624 thereby displacing water which has remained in the tube 624 from the last purging cycle through the waste valve 690 and into the waste receptacle.

The amount of serum picked up is determined by the amount of time which the valve rod 666 is maintained in a retracted position. After the appropriate amount of time, the voltage to the solenoid driver 636 is reversed, thereby causing the valve rod 666 to extend and seal the serum pickup passage 684 with the valving member 676. The electronic logic control thereafter closes the pressurization valve 648 and opens the venting valve 644 to allow the pressure in the serum cup 30 to be dissipated before the horizontal arm 140 rises.

The air cylinder 600 thereafter moves the spline shaft 148 and thereby the horizontal arm 140 to their uppermost position as determined by the position nuts 616 on the vertical guiding rod 610. The stepping motor 180 then initiates the swing of the horizontal arm 140 toward the test chemistry wheel 18. Intermediate this swing, the pickup and pressurization tube 624 and 622 pass over the waste receptacle 296 in the top of the lower housing 12. At this time, the high pressure purge valve 646 is opened to present high pressure air to the pressurization tube 622. This high pressure air wipes off the outside of the serum pickup tube 624 to insure that no extra serum has been retained on the exterior surface of this tube 624. This air flow is maintained for approximately 1/2 second, after which the swing of the horizontal arm 140 continues toward the test chemistry wheel.

When the serum pickup tube 624 is in position over a test tube 33 in the test chemistry wheel 18, the serum pickup solenoid 636 is again energized to retract the valving member 676, and the water valve 696 is concurrently opened to present pressurized water to the valve chamber 674. The water, being under pressure, forces the serum in the pickup tube 624 to flow out into the test tube 33. Again, the appropriate amount of dispensed serum depends on the amount of time which the valve rod 666 is held in its retracted position. Appropriately, the voltage on the solenoid 636 is reversed to extend the valve member 676 against the right resilient member 692 to thereby close off the pickup tube 624 from the water valve 696. This valve 696 is then also closed.

Having completed the dispensing of the serum sample, the horizontal arm 140 is then swung back toward the specimen wheel to pick up the next serum sample from the cup which has been indexed into the transfer position 126 by the serum specimen wheel 16. However, intermediate this return swing, a purging procedure is performed which removes all traces of the previous serum sample from the pickup tube 624 thereby preventing any danger of cross contamination between samples. The horizontal arm 140 pauses in its swing as the pickup tube 624 becomes vertically aligned with the receptacle 296 in the top of the lower housing 12. At this time, the water valve 696 whose output port leads to the valve chamber 674 in the pickup valve 652, is opened, to allow pressurized water to flow through the valve chamber 674 and into the pickup tube 624. This water exits the pickup tube 624 and is deposited into the waste receptacle 296. At the same time, the purging air valve 646 is open to permit high pressure air to flow through the pressurizing tube 622 to blow off the outside of the serum pickup tube 624. Concurrently with the air flow, a water valve 698, which is connected to the directed purging tube 634 in the horizontal arm 140, is opened which shoots water against the outside of the pickup tube 624. The downward flowing air and the inward shooting water generates an aerated water turbulence along the exterior surface of the pickup tube 624 which thoroughly cleanses it. The pickup water valve 696 is then closed to stop the flow of water through the pickup tube 624 and the purging water valve 698 is also closed to stop the water flowing in the purging tube and against the outside of the tube pickup 624. The purging air valve 646 is thereafter held in an open position for a short time to effect a drying of the outside of the tube 624. The arm 140 then continues toward the specimen wheel to repeat the operation of picking up a serum sample.

The valve chamber 674, as well as the water and waste passages 686 and 682, can also be purged as desired, preferably at the beginning of a test cycle. This initial purge is performed by opening the waste valve 690 and the water valve 696 while maintaining the valve rod 666 in its extended position to seal off the serum pickup passage 684. This allows water to circulate in the valve chamber 674 and exit through the waste valve 690. Due to the extended position of the valving member 676, an amount of the water will leak around the valve rod 666 only to be directed to waste through the waste passage 670 through which the rod 676 passes.

The initiation of a test series, in addition to each sample pickup in that series, causes the test chemistry wheel 18 to index empty test tubes 33 into the transfer position 127 to receive a serum sample. The drive and controlling devices for the test chemistry wheel 18 are shown in FIGS. 10-11 and comprise essentially the same type of components as that of the specimen wheel 16. The test tubes 33 are inserted and supported in holes 300 in the top 302 of the test chemistry wheel. They are permitted to rest and ride on the bottom of the tube-receiving channel 304 and are supported in a vertical position by a supporting plate 306. The top 302 of the test wheel 18 and the supporting plate 306 are centrally mounted on a main drive shaft 308. The shaft 308 is rotatably driven through a driving pin plate 310, a barrel cam 312 and a one-half turn clutch 314 by the same motor 98 which drives the specimen cup wheel 16.

The test chemistry wheel drive shaft 308 is rotatably mounted in bearing blocks 316 and 318 which are supported in a drive shaft housing 320. The bottom of the shaft is mounted in thrust bearings 322 in a hub 324 before being terminated and secured by a lock nut 326 on the bottom side of the hub 324. A flange 325 extending from the bottom of the drive shaft housing 320 supports the end brackets 328 in which the shaft 330 carrying the driving cam 312 is mounted in bearings 332.

The electronic logic control energizes the one-half turn clutch 314 in the test wheel 18 as the horizontal sample transfer arm 140 begins its 180.degree. swing to the specimen wheel 16 to extract a serum sample. The cam 312 is rotated thereby to drive the pin 334 in communication with its track which results in a rotary movement of the test chemistry wheel. The wheel 18 continues to index through test tube positions until the arrival of a test tube 33 into the serum sample transfer position 127 is detected by a detection device 336 mounted in the base of the test wheel 18 below the supporting plate 306.

The detection device 336 comprises a deflection arm 338 which is connected to an activating arm 340 extending from a housing 343. The activation arm 340 is connected to a slidable, optically black blade member 342 which contains a hole 344. The deflection arm 338 is positioned so that a test tube entering the transfer position 127 in the test chemistry wheel will cause deflection of the arm 338 thereby pushing the activating arm 340 and sliding the hole 344 in the optically black blade 342 into communication with a light source 346 and a photocell 348. The resulting electrical signal from the photocell 348 is detected by the logic control resulting in the de-energization of the one-half turn clutch 314 which stops the rotation of the test chemistry wheel.

The relative position of the test chemistry wheel 18 can be recorded in a memory portion of the control logic by the use of a position detection disk 350. This disk 350 is mounted on the driving cam shaft 330 so that it makes one-half revolution each time the cam drives a pin 334 to index the test chemistry wheel one position. Holes 352 in this disk 350 communicate with a light source 351 and a photocell 353 each time the disk 350 and the cam make one-half of a revolution. The number of the resulting electrical pulses from the photocell 353 is recorded in memory by the control logic for later utilization.

The above-described transfer of serum samples to the test chemistry wheel 18 for receiving a specific chemistry analysis is continued until the specimen wheel 16 has made a complete revolution and the first sample cup position is again in the "home" position 129. The control light is signalled that this event has occurred by an optic detection device 358, as shown in FIG. 3. This device 358 has a deflection arm 360 which is connected at its end to a deflection member 362 shaped to communicate with a notch 364 in the periphery of the driving pin plate 68. The notch 364 is located adjacent the pin 370 which corresponds to the home position 129. The deflection member 362 and arm 360 are held in a deflected position by the periphery of the driving pin plate 68 as the plate rotates.

Upon reaching the home position 129, the notch 364 in the plate 68 permits the spring loaded deflection arm 360 to extend, which brings a hole 372 in a blade 374 into communication with a photocell 376 and light source 378. The resulting electrical signal from the photocell 376 signals the control logic that all of the cup positions in the specimen wheel have been tested for a displaced patient-identification selection switch 108. Movement of the specimen wheel 16 is terminated for the remainder of the test in progress.

As shown in FIG. 2, the test tubes in the test chemistry wheel 18 pass beneath dispensing heads 26, 27 and 28 after leaving the transfer position 127. It may be that the first of these passes is caused by empty test tubes being indexed into the transfer position 127 to receive a serum sample. The first of the dispensing heads 26 is a "dispense only" apparatus, and is identical to the other two dispensers 27 and 28 except that it does not have means by which to mix the chemical reagents supplied therefrom with the serum sample. The two subsequent dispensers 27 and 28 having mixing apparatus included therewith so that the reagents that are added to the test tubes from these heads 27 and 28 may be mixed with the sample to insure uniform distribution of the reagents within the serum. The uniform distribution of reagents avoids "hot spots" of reagents within the serum sample which would yield erroneous test results, when the test chemistry is subsequently analyzed, which would result from the non-homogeneity of the mixture.

One of the combination dispensing and mixing heads 27 and 28 is shown in FIG. 12. These heads are mounted in the top of the lower housing 12, as by bolts 357, and generally comprise a lower dispensing unit 354 and an upper mixing unit 356. The dispensing unit 354 is stationary, while the mixing unit 356 is reciprocated up and down by a rod 359 which is fastened at its upper end to the mixing unit 356 and at its lower end to a piston in an air cylinder (not shown). The air cylinder provides the necessary up and down stroke to place a mixing rod 361 extending from the mixing unit 356 through a channel 363 in the stationary dispensing unit 354, into the serum and reagent combination in the test tube 33 located therebelow. The upper end of the stirring rod 360 is connected by a coupling 365 to the shaft 366 of a stirring motor 368. The stirring shaft 360 is comprised of a stainless steel rod 371 over which has been slipped a piece of inert and chemically resistant tubing 373 such as that sold by the DuPont Corporation under the trademark Teflon. The lower end 375 is sealed to prevent any of the test chemistry from entering the tubing 373.

In operation, reagents which have been selected by apparatus hereinafter to be described, are supplied to three channels 377 in the dispensing head 354 by separate tubes 379. The channels 377 lead to openings 380 above the waiting test tube 33 from which the reagents are dispensed. The mixing head 356 is then moved downward by its controlling air cylinder (not shown) and the stirring motor 368 is turned on by the logic control. The stirring rod 360 passes down into the test tube 33 and the combination of the serum sample and the chemical reagents which have been added by the dispensing head 354. The spinning rod 360 rapidly combines the mixture and uniformly distributes the reagents throughout.

On signal from the logic control, the rod 359 again is extended by the air cylinder and the stirring rod 361 is retracted from the test tube 33, and the stirring motor 368 turned off. The high speed at which the shaft rotates, preferably about 6000 rpm, coupled with the surface characteristics of the shaft 361, throws all the chemistry off into the test tube as the shaft is extracted, thereby eliminating any possibility of later cross-contamination. The test chemistry wheel 18 is indexed to present an empty test tube to the transfer position 127 so that the test tube 33 containing the just-formed and mixed test chemistry is indexed to another dispensing station 28 or to the test chemistry transfer position 455, as shown in FIG. 1.

An alternate embodiment of the dispensing and mixing head utilizing a different mixing technique, is shown in FIG. 22. The alternative apparatus generally comprises a lower dispensing unit 702 and an upper and movably mounted mixing unit 704. The dispensing unit 702 is stationary, while the mixing unit 704 can be reciprocated up and down as by an air cylinder 706. Activating air for the air cylinder 706 is supplied from a pressurized air supply to a manifold block 708 and by a passage 710 therein to an inlet port 712 in the air cylinder 706. The air passage 710 in the manifold block 708 is preferably a tube which is inserted in the manifold block and which extends downwardly therefrom to communicate with the tube 714 leading from the valve for the pressurized air supply. The manifold tube 710 is sealed in the supply tube 714 as by a threaded rubber coupling 716. This two part construction permits the manifold block 708 to be easily disconnected from the top of the lower housing 12.

Air is provided to the cylinder input port 712 to lower the mixing unit 704 and extend a mixing tube 716 substantially all the way into the test tube which is in position under the apparatus. The mixing tube 716 is comprised of a stainless steel tube 718 over which a flexible, chemically inert tube 720, such as Teflon, is slidably mounted. The two tubes 718 and 720 are fastened together within the mixing unit 704 by a threaded rubber cap 722. The stainless steel tube 718 is terminated shortly above this cap 722, with the flexible tube 720 continuing out the top of the mixing unit 704 and into a flow control valve 724 mounted on the rear 726 of the mixing unit 704.

More specifically, air is ported to the air cylinder inlet port 712 after the specified reagents have been added through reagent dispensing tubes 728 into the test tube 33. The air forces a piston and piston shaft 730 downwardly within the air cylinder 706. The piston shaft 730 is connected at its upper end to the lower side of the mixing unit 704. As a result, the mixing unit 704 is lowered along a vertical guiding rod 732 into the solid line position shown in FIG. 22. As the unit 704 is lowered, the mixing rod 716 passes down, out of the lower dispensing unit 702 and into the test tube 33. Inert air, preferably nitrogen, is, at the same time, supplied through the rate control valve 724 to the mixing tube 716. The gas leaves the lower end of the mixing tube 716 in the form of bubbles which pass up through the contents in the tube 33 and escape through the upper surface of the solution. The bubbling action, the rate of which is controlled by the rate control valve 724, thoroughly mixes the reagents and serum forming the solution in the test tube 33 at that moment to provide a homogeneous mixture.

At the conclusion of the predeterminable mixing time, as dictated by the logic control, the control valve (not shown) supplying the air to the cylinder 706 is closed, thereby allowing a spring (not shown) within the cylinder 706 to return the mixing unit 704 to its upper, dotted line position shown in FIG. 21. The arrival of the unit 704 at its upper position is detected by the logic control by means of a magnetic detector (not shown) which can be mounted at the lower end of a detector rod 734. This rod 734 extends through the dispensing unit 702 and is secured in the mixing unit 704 as by threads 736. The primary purpose in the use of this rod and vertical detecting mechanism is to prevent any indexing of the test chemistry wheel 18 while the mixing unit 704 is in its downward position.

The apparatus used in selecting the proper reagents and controlling the amount of each that is dispensed is shown in FIGS. 13 through 15. A main selector valve 384 is shown which is capable of selecting reagents for a plurality of different tests or chemical analyses. The selector valve 384 comprises a main valve body 386 which can be made up of six individual valve bodies 388. Each of the valve bodies 388 has a main selector valve solenoid 390 and five individual double ended reagent valves 392 associated therewith. The main selector solenoids 390 each have a control rod 394 which extends through the respective valve body 388 and is mounted on a selector valve plate 396 by means of snap rings 398.

Each solenoid 390 controls the upper and lower end of five selector valve stems 404 in the reagent valves 392 by means of this plate 396. Each respective selector valve 392 has a return spring 400 mounted between shoulders 402 on its upper end. The valve stems 404 extend through the valve body 388 and are connected on the other side by snap rings 406 to the valve selector plate 396. Each end of the valve 392 has a central channel 408 and 410 which terminates in a T-slot 412 and 414, respectively. A plurality of O-ring pairs 416 isolate these T-slots 412 and 414 from each other and from the reagent-carrying channels 418 and 420 in each of the individual valve bodies 388.

The top ends 393 of the selector valves 392 are associated with a different test or tests than the bottom ends 395. Each of the selector valve ends 393 and 395 have a different reagent, if desired, connected to its central channel 408 and 410, as by Teflon tubing, from the reagent supply bottles 20 in the lower machine housing 12. The reagents in these bottles are kept under constant pressure through the use of pressurized nitrogen which is inert and will not cause degradation of the reagents.

In operation, the main solenoid 390 associated with the selector valves 392 having the desired reagents connected to them is energized to extend its control rod 394 and move its connected valve selector plate 396 away from the valve body 386. This action by the plate 396 causes the valve stems 404 of the five selector valves associated with that solenoid 390 to move under control of this actuation plate 396. The valve stem 404 movement brings the two cross T-slots 412 and 414 in the valve into communication with the two main valve body channels 418 and 420 respectively. Only one such solenoid 390 and its associated selector valves 392 are energized for any given test. Each of the 10 reagents connected by tubing from their pressurized bottles to the ends 393 and 395 of the selector valves chosen are now available to the respective main reagent channels 418 and 420 in the valve body 386. The reagents are able to flow in the main reagent channels 418 and 420 around the unselected selector valve stems and between defining "O" ring pairs 416.

A differentiation must be made between the upper level selector valve ends 393 and the lower level selector valve ends 395. Only the reagents supplied to one end, upper or lower, are required for any one test. To make this differentiation, a level selection solenoid 424 is used to move a selector valve actuation plate 426 in correspondence with the level of a particular set of selector valves 392 needed for a particular test. An upper/lower level selection valve 328 has spaced shoulders 430 on its upper end for receiving a return spring 432 and is connected at its lower end, on the opposite side of the valve body 386, to the actuation plate 426. A path or channel is provided, as may be seen from FIG. 15, for the reagents in the lower level valve ends when the upper/lower selection solenoid 424 is de-energized. When energized, the solenoid 424 extends its actuation rod 425 and moves the actuation plate 426 carrying the lower ends of the valves 428 away from the valve body. This action interrupts the path for the lower level reagents and brings the upper level reagents into communication with their outlets 434.

The chosen reagents pass through the appropriate upper or lower level channels provided for them and are made available to one side of extremely fast acting and accurate dispensing valves 436. The outlet sides of these dispensing valves 436 are connected to the individual tubes 379 leading to the dispensing heads 27 and 28. Two of these valves are connected to one head 27 while three are connected to the other dispensing head 28.

The reagents needed for a test are presented to the inlet side of the dispensing valves 436, as above described, as soon as a test cycle is initiated. The individual dispensing valves 436 are selectively energized by the control logic when a test tube carrying a serum sample is positioned beneath the respective dispensing head 27 and 28. The first dispensing head 26, which has no mixing unit, is used for the dispensing of highly contaminable reagents, e.g., as used in a test for cholesterol or glucose. The reagents pose extreme danger of cross-contamination which would render the test chemistries unusable. These reagents are not selected by the selection valve 384 but are supplied to the dispensing head 26 directly from their pressurized bottles by means of separately activated dispensing valves (not shown) which are identical to the other dispensing valves 436.

The main reagents are added at the proper time by the last two dispensing heads 27 and 28. The logic control initiates the appropriate dispensing valves 436 for the required amount of time to dispense a precise amount of each specified reagent into the waiting test tube. When the dispensing is completed, the mixing unit descends and mixes the serum and the newly added reagents. After mixing, the mixing head unit ascends and the test tube is indexed to the next dispensing head 28 or to the test chemistry transfer position 455, depending on where the test tube 33 is at the time. At the completion of a test series, the channels 418 and 420 in the selector valve 386 are washed out with water supplied through a valve 437 to an inlet 439 in the valve body 386.

The selector valve may also be purged before a test is begun with the reagents that will be used in that test. This may be done by using a purge test tube which does not receive a serum sample, but is indexed through the dispensing stations to receive the test reagents. The flow of specific reagents in the selector valve 386 and dispensing valves 436 removes any water or reagent left from a previous test.

An alternate reagent selection apparatus is illustrated in FIGS. 23, 24 and 25. The main valve assembly 738, shown in FIGS. 23 and 24, is comprised of a plurality of individual valving units 740 which are secured together to comprise the main valve assembly 738. In this instance, the main assembly 738 is grouped for operation into two general columns of valves 742 and 744, each having rows containing five of the valving units 740. The assembly 738 may have any number of rows, but, in the illustrated embodiment, the right hand column group 744 has eight rows 746 through 753 and the other group has seven rows 754 through 760. The first row 754 of valves in the left hand column group 742 is used as the output dispensing valves to the dispensing and mixing apparatus 27 and 28.

The operation of the valve assembly 738 is best described with respect to FIG. 25 wherein one of the individual valving units 740 is illustrated. Each of these units 740 comprises a valve block 762 with a cavity 764 therein. A solenoid driver 766 is mounted, as by screw threads 768, into the top, open side of the cavity 764 in the valve body 762. A valve driver 770 is movably supported within the solenoid 766 by a spring 772 at its upper end and a resilient diaphragm 774 at its lower end. Movement of the driver 770 is effected by energizing the solenoid coil 775 which compresses the spring 772 and moves the diaphragm 774 upwardly. The upward movement of the diaphragm 774 permits an inlet port 776 to communicate with the enclosed cavity 764 within the valve body 762. A tube 777 for conveying a reagent from a pressurized reagent bottle 20 to this port 776 is secured in the lower portion of the port 776 by a threaded connector 779. The valve body 762 has an inlet passage 778 and an outlet passage 780 which open into the central cavity 764. The inlet passage 778 is aligned and in communication with the outlet passage 780 of the respective unit 740 in the immediately preceding row. Likewise, the outlet passage 780 is in communication with the inlet passage 778 of the valve unit 740 immediately following. O-rings 782 and 784 provide the necessary seals between the valve units 740. This tandem coupling of the inlet and outlet passages 778 and 780 is best seen in FIG. 24.

The individual valve units 740 are, as previously mentioned, arranged within each general group 742 and 744 in rows of five units each. An entire row of five valve units 740 is selected for each different test to be performed on a serum sample. In operation, each of the five solenoids 766 in the particular row of valves 740 having the reagents for the particular programmed tests supplied thereto is energized along with the valves in the dispensing valve row 754. Only one row of five solenoids of the reagent selection rows 746-753 and 753-755 are energized at any one time. The reagents coupled to the respective inlet ports 776 of the energized row of selection valves enter their respective valve bodies, flow into the internal cavities 764 and exit therefrom by the outlet passages 780. The reagents flow on into the inlet passage 778 in the next valve body 762 in that column, circumvent the diaphragm sealed inlet port 776 in the next valve body, and leave that valve body by means of the outlet passage 780. This flow continues until, if the selected row of valves is in the left hand group 742, the reagents enter the dispensing valve row 754. In the case where the selected row is in the right hand column 744, the outlet passages 780 of the top row of valve units 746 in FIG. 23 are respectively coupled, as by tubes 786 through 790, to what has heretofore been called the outlet passages 780 of the dispensing row of valves 754 in the first group 742. The valves in the dispensing row 754 are identical to the other valves except that their inlet and outlet passages 778 and 780 are both used as inputs and the inlet port 776 is utilized as the output port to the reagent tubes 379 leading to the dispensing and mixing stations 27 and 28.

It should be seen, that only the reagents coupled to the selected rows 746-753 and 755-760 of valve units 740 will be able to flow into the respective valves in the dispensing valve row 754 and out the heretofore called inlet ports 776.

In the case where only three reagents, for example, are needed for a particular test, all of the reagents coupled to the five, selected valving units 740 in the selected valve row 746-753 and 755-760 are presented to the dispensing valve row 754. It is the valves 740 in the dispensing row 754 which then are selectively energized to dispense, or not to dispense, the particular reagents available to that valve. The output tubes 379 of the dispensing row 754 of valves are the input tubes 379 leading to the dispense and mixing stations 27 and 28.

Preferably the reagents needed for a test are presented to the inlet side of the dispensing row of valves 754 as soon as a test cycle is initiated and all of the valves in the dispensing row 754 and the particular reagent selection row 746-753 and 755-760 are energized to permit the reagents to be used during that test to flow into and through the dispense valves. Desirably, both the selected valve row 746-753 and 755-760 and the dispense valve row 754 remain energized until all of the dispense valves and the dispense tubes 379 have the respective selected reagents therein. The selected valve row 746-753 and 755-760 then remains energized while the dispense row 754 is turned off. This purging with reagents insures that any water or reagent left in the individual units or tubes is flushed out, and that a precise amount of the reagents will be dispensed by the dispensing valves when appropriately energized.

At the conclusion of a test analysis, the various inlet and outlet passages 778 and 780 in the valve assembly 738 can be purged or flushed out with water. This is accomplished using a row of purging valves 792 which have their inlet ports 776 coupled as by tubes 794 to a pressurized water supply (not shown). The passages 778 and 780 in the bodies of these valves are individually coupled by a tube 796 to this inlet passage 778 in respective ones of the valve units 740 in the bottom row of valves 760 and 753 in the two major valve columns 742 and 744. Using both the inlet and outlet passages 778 and 780 of each of the valves 740 allows five purging valves to be used to purge the 10 columns of selection valves.

The row of dispense valves 754 are energized at the same time the purging valve row 792 is energized during the water purging. Water is thereby permitted to flow through all of the tandemed inlet and outlet passages 778 and 780 in the valve assembly 738, through the dispense valves 754 and through the dispense tubes 379. The purging and dispensing valves 792 and 754 are then de-energized to stop the purging process and await the next test.

There are several options available to the programmer in effecting the desired test. These options are partially controlled by the nature of the test to be performed. A normal chemical serum analysis may be performed by adding the reagents as hereinbefore described and then extracting an amount of the thereby-formulated test chemistries as the test tubes 33 pass beneath the test chemistry extraction head 29. The extraction procedure, as well as the analysis procedure, will be described in more detail below.

However, there are certain serum chemistry test analyses which must provide incubation periods after the addition of one or more of the reagents and before the addition of subsequent reagents. In many instances, this incubation period must take place at a precise, elevated temperature. In accordance with these requirements, all of the reagents may not be dispensed to the test tubes on their first pass beneath the dispensing heads 26 through 28. Furthermore, during certain tests, certain of the reagents must be added to the test tubes and the mixture raised to a specific temperature before the serum samples are added. The incubation periods are controlled by the control logic, but the increase in temperature must be provided for by means in the test wheel.

A system shown diagrammatically in FIG. 16 is provided to furnish the rapid elevation to the precise temperatures needed. Specifically, a reservoir 440 is filled with a fluid 442 which has been treated to resist bacteria growth. This fluid 442 is constantly recirculated by a pump 444 through a heater 446 and back to the reservoir 440. When an incubation is programmed which requires that the reagents be at an elevated temperature, a valve 450 in this constant recirculation path directs the heated fluid 442 into the channel 304 in the test wheel 18 and into communication with the test tubes 33 carried therein. One or more sensors, such as thermistors, are positioned about the circumference of the test wheel in this channel 304 to control the heating of the fluid in the heater 446, in accordance with the desired temperature.

The fluid is pumped into the channel 304 until an overflow condition is reached, as defined by the height of an overflow outlet 452 (FIG. 11) which directs the fluid back to the reservoir 440. The fluid continues to recirculate on this path into and out of the test wheel channel 304, until the control logic signals the termination of the elevated temperature incubation period. At this time, the valve 450 leading from the heater 446 no longer directs the fluid to the test wheel channel 304 but recirculates it into the reservoir 440. An exit port 453 in the bottom of the test wheel channel is also opened to drain the fluid already in the channel back into the reservoir.

The temperature at which the fluid has been raised may then be above that which is desired for recirculation purposes. In such event, a second valve 448 which is supplied directly from the pump 444 directs the fluid through cooling condenser coils 454 and then back to the reservoir 440. The fluid continues to recirculate on this path until the desired temperature level is reached at which time it is permitted, by the second valve 448, to recirculate through the heater and heater valve 450 back to the reservoir 440.

The various tests which may be performed, as well as the sequencing of serum transfers, reagent dispensing, and proper incubating techniques are all under the control of the control logic and are described in detail in the above-mentioned co-pending application. The completed test chemistry is extracted by the test chemistry extraction apparatus 29 after the appropriate reagents have been added and all incubations completed.

The extraction head apparatus 29 is shown in more detail in FIG. 17. It is supported in the top of the lower housing 12 by a tubular support member 456 which contains a vertically movable rod 457. The rod 457 supports, at its upper end, a horizontal arm 458. A resilient stopper 460 similar to that used in the serum sample transfer arm 140 is secured beneath and projects into the arm 458 at one end thereof. This stopper 460 contains two stainless steel tubes 462 and 464 which are connected within the stopper 460 to the ends of flexible tubes 466 and 468. The shorter of the stainless steel tubes 464 is connected by its flexible tube 468 to the outlet of a pressurization valve 470 whose inlet is connected to the pressurized air supply 471.

The lower end of the vertically moving rod 457 is connected to the piston rod 472 of an air cylinder 474. Pressurized air is supplied to the top inlet port 475 of this air cylinder 474 to move the piston rod 472 in a downward direction. This causes the horizontal arm 458 to descend on a waiting test tube 33, immerse the longer tube 462 of the two stainless steel tubes in its stopper 460 in the test chemistry contained in that test tube 33 and seal the top of the test tube 33 with the stopper 460. The other end of the tubing 466 connected to the longer stainless steel rod 462 passes through the hollow air cylinder piston rod 472 and air cylinder 474 and is made available to a flow cell 479 as used in a spectrophotometer. The other side of the flow cell 479 is connected to the inlet of a valve 485. The other side of this valve 485 is connected to a waste receptacle 486.

In operation, when the control logic senses that all the reagents have been added and any incubation period completed, the test tubes 33 containing the completed test chemistries are successively indexed into the test chemistry extraction position 455. A portion of each test chemistry is extracted and made available to the flow cell 479 for analysis, after which the next test chemistry is indexed into the extraction position 455 and the process repeated. More specifically, the indexing of a completed test chemistry into the extraction position initiates the closing of the air valve 476 to provide pressurized air to the top inlet port 475 of the air cylinder 474. This causes the horizontal arm 458 to descend and seat its stopper 460 against the top of a waiting test tube 33. The pressurization valve 470 is then opened permitting pressurized air to be applied to the contents of the test tube through the short stainless steel tube 464 in the stopper 460. The flow cell valve 485 is opened to permit test chemistry to be forced out of the test tube 33 by the air pressure, into the extraction tube 462, through the connected flexible tube 466 and into the flow cell 479.

A large amount of the test chemistry is permitted to flow in this manner through the extraction tubes 462 and 466, through the flow cell 479, and to waste through the valve 485 before the flow cell valve 485 is turned off to trap test chemistry in the flow cell. The excess flow of test chemistry is used to wash the tubes, the flow cell and the cell valve of the previous test chemistry thereby avoiding any cross-contamination which might affect the subsequent spectroanalysis.

The spectroanalysis of the test chemistry is conducted in a conventional spectrophotometer which has been modified to provide means by which the flow cell is moved in and out of the requisite light path, instead of disturbing that path with rotating mirrors as is often done.

The flow cell 479, as shown in FIG. 18, is supported by bearings 488 on a rail 490 which permits and guides linear movement of the flow cell 479. The base of the flow cell is connected, as by a pin 492, to a slotted member 494. A finger member 496 is mounted on, and is eccentrically driven by, a wheel 498 and moves within the slot 495 in the slotted member 494. A shaft 500 is eccentrically mounted by ball bearings 502 to this finger supporting wheel 498. The shaft 500 is also connected to a second rotating wheel 504 at a location offset from the center of rotation of that wheel 504. The latter wheel 504 is rotated at approximately 30 rounds per minute by an electric motor 506.

As the motor 506 rotates this wheel 504, the finger-supporting member 498 is eccentrically driven to reciprocate the flow cell 482 on its supporting rod 490. As can be seen from FIG. 18, this reciprocation serves to move the flow cell and the test chemistry contained therein into and out of the light path. The reciprocation of the flow cell and test chemistry provides a continuous source of calibrating signals for the spectrophotometer. Electronic logic may be associated with the spectrophotometer to process its output and transform it into various forms of usable data.

At the conclusion of the spectrophotometer analysis, the inlet air valve 475 (FIG. 17) closes and air is instead supplied through a second valve 477 to the lower side of the extraction head air cylinder 474 (FIG. 17). The resulting movement breaks the seal of the resilient stopper 460 on the top of the test tube 33 and the horizontal arm 458 is returned to its uppermost position. At the conclusion of each test the pressurization valve 470 supplying the pressurizing air is turned off.

An alternate embodiment of the extraction head apparatus 29 is shown in FIG. 26. In this apparatus, the extraction head 806 is reciprocated up and down at the appropriate time, by an air cylinder 800 which is similar to the cylinder 706 used in the alternate embodiment of the mixing and dispensing apparatus 27, 28 shown in FIG. 22. Air, under pressure, is supplied to an input tube 803 which is coupled to an inlet passage 804 in a manifold block 807. The inlet passage in turn supplies an inlet port 802 in the air cylinder 800 to force the piston contained therein downwardly. A piston output shaft 805 is secured to the underside of the horizontal arm thereby transmitting the downward motion to the extraction head 806. The extraction head 806 is guided in this downward movement by a vertical rod 808 on which the head 806 is movably supported as by bearings 810. The lower position of the extraction head 806 is specified by the travel of the piston shaft 805 within the air cylinder 800, and is detected by means of a sensing rod 812 which is secured, as by threads 814 in the lower portion of the extraction head 806. At the lower position, this sensor rod 812 makes contact with a detection means, such as a switch or a magnetic sensor (not shown), which in turn generates a signal indicative of such lower position. This signal is used to inhibit the electronic control logic during the time which the extraction apparatus 806 remains at its lower position, to prevent any indexing of the test wheel 18.

The extraction of the completed test chemistry from the test tube 33 in the extraction position 455 on the test wheel 18, is performed by a stainless steel tube 816 which is inserted into the test tube 33 and test chemistry as the extraction head 806 moves downwardly. The extraction tube 816 extends up, into the extraction head 806 and is fitted into the lower end 818 of the flexible tube 466 which leads to the flow cell 479. A tight seal is maintained between these two, interfitting tubes 816 and 466 by a threaded rubber cap 822.

A slightly enlarged cavity 824 is provided immediately below the lower end 818 of the flexible tube 446. The stainless steel extraction tube 816 is held in a generally centered position in this cavity 824 by its secured connection in the rubber stopper 822, and extends downwardly through the cavity 824 and through a resilient stopper 826 before emerging from the lower side of the extraction head 806 to communicate with contents of the test tube 33. A second, flexible tube 828 communicates with this cavity 824 and is secured in place with a threaded coupling 830. The second tube 828 supplies the cavity 824 with pressurized air from a flow control 832 mounted on the rear side 833 of the extraction head 806. The extraction head 806, in its downward position, seals the top of the test tube 33 with the resilient stopper 826 which permits the pressurized air flowing into the cavity 824 to pressurize the contents of the test tube 33. When the flow cell valve 485 is subsequently opened, this pressurized condition forces test chemistry from the test tube 33 up into the stainless steel extraction tube 816, through the flexible tubing 466 and into the flow cell 479.

When the predetermined amount of test chemistry has been extracted, the air supplied to the inlet port 802, by means of the manifold 807 and supply tube 803, is turned off, thereby allowing a spring (not shown) within the air cylinder 800 to return the extraction head 806 to its upper position and await the indexing of the next test chemistry into the extraction position.

The entire process is repeated when the next test chemistry carrying test tube 33 is indexed into the extraction position 455 and continues until all the test chemistries have been analyzed by the spectrophotometer. The used test tubes are discarded by opening a trap door in the bottom of the test tube channel 304 (FIG. 11) which is arcuately disposed after the extraction position 455. At the conclusion of all the tests of one type, a purging valve 508 leading from a pressurized water supply to the extraction tube 466 is opened, as is the flow cell valve 485. Water is thereby permitted to purge the extraction tubes 462 and 466 and clean the chemistry passages within the flow cell 479 and flow cell valve 485. The purging valve 508 is closed at the completion of the cleansing cycle.

Claims

We claim:

1. Apparatus for preparing a succession of serum chemistries for analysis, comprising serum conveyor means for conveying a plurality of specimen containers each containing a serum specimen along a first path; chemistry conveyor means for conveying a plurality of chemistry containers along a second path; a transfer arm; drive means for driving said transfer arm between successive communication with preselected ones of said specimen containers and communication with successive ones of said chemistry containers; sealing means carried in said transfer arm for sealing a specimen container when said arm is in communication therewith; first tube means carried in said transfer arm and having one end for communicating with the specimen container sealed by said sealing means, the other end of said first tube means being coupled through first valve means to a first fluid under pressure, said first valve means being selectively operable to admit said first fluid to the sealed specimen container to pressurize said container; second tube means carried in said transfer arm and having one end for reception in the serum specimen in the sealed specimen container, the other end of said second tube means being coupled through second valve means to venting means, said second valve means being selectively operable for a predetermined time period to allow the pressure in said sealed container to induce a predetermined amount of the serum specimen to flow into said second tube means; third valve means coupled between the other end of said second tube means and a second fluid under pressure, said third valve means being selectively operable for a predetermined time period when said transfer arm is in communication with one of said chemistry containers to cause a predetermined amount of the serum specimen in said second tube means to flow into said chemistry container; and dispensing means for selectively dispensing a predetermined and repetitive amount of a reagent into each of the chemistry containers to form serum chemistries.

2. Apparatus as set forth in claim 1 with the addition of extraction means for successively extracting a predetermined portion of the formulated serum chemistries for analysis.

3. Apparatus as set forth in claim 1 wherein said first valve means is selectively operable to admit said first fluid to said sealed specimen container to raise the pressure in said container to a predetermined level, and to maintain said level while said second tube means is vented.

4. Apparatus as set forth in claim 1 with the addition of fourth valve means coupled between the other end of said first tube means and second venting means, said fourth valve means being selectively operable to release the pressure in the specimen container after the predetermined amount of the specimen has been induced to flow into said second tube means.

5. Apparatus as set forth in claim 1 wherein said serum conveyor means includes rotary drive means for successively presenting said preselected specimen containers to a transfer station for communication with said transfer arm.

6. Apparatus as set forth in claim 1 wherein said chemistry conveyor means includes rotary drive means for successively presenting said chemistry containers to a receiving station for reception of a predetermined amount of one of said serum specimens.

7. Apparatus as set forth in claim 1 wherein said second tube means is supported in and protrudes from said sealing means, whereby said second tube means is inserted into the serum specimen in a specimen container when said sealing means is in sealing engagement with the specimen container.

8. Apparatus as set forth in claim 1 wherein said first tube means is supported in and protrudes from said sealing means, whereby said first tube means communicates with a specimen container when said sealing means is in sealing engagement with the specimen container.

9. Apparatus as set forth in claim 1 wherein said first tube means is supported in and protrudes from said sealing means, and said second tube means is disposed within the hollow of said first tube means, whereby said first and second tube means communicate with a specimen container when said sealing means is in sealing engagement with the specimen container.

10. Apparatus as set forth in claim 1 wherein said transfer arm includes purge means for removing any serum from the external surface of said second tube means after the transfer arm is out of communication with the specimen container.

11. Apparatus as set forth in claim 1 wherein said dispensing means includes selection apparatus for selecting and supplying a predetermined amount of a reagent from among a plurality of reagents.

12. Apparatus as set forth in claim 44 wherein said dispensing means comprises a plurality of reagents each contained in an individual reagent container pressurized to a substantially constant pressure level, each of said reagents having a delivery tube with one end received therein and the other end for communication with said plurality of chemistry containers, an individual reagent valve coupled to each delivery tube for selectively opening and closing said delivery tube, said reagent valves being selectively operable for predetermined time periods to allow the pressure in the respective reagent containers to cause a flow of predetermined and repeatable amounts of selected ones of said reagents into successive chemistry containers.

13. Apparatus as set forth in claim 1 with the addition of mixing apparatus for selectively mixing the contents of the chemistry containers.

14. Apparatus as set forth in claim 13 wherein said mixing apparatus comprises a motor, a mixing member operatively connected to said motor for rotation thereby, said mixing member having reciprocation means coupled thereto for positioning said mixing member into and out of the chemistry containers to selectively immerse said mixing member in the contents of the chemistry containers.

15. Apparatus as set forth in claim 13 wherein said mixing apparatus comprises a mixing member having a passage therein, a pressurized gas supply coupled to said passage, means for reciprocating said mixing member into and out of the chemistry containers to immerse said mixing member in the contents of the chemistry containers to bring said passage into communication with the container contents whereby the pressurized gas is induced to flow through and mix said contents.

16. Apparatus as set forth in claim 1 including identification means for identifying the preselected specimen containers which are to have a predetermined amount of the serum specimen therein transferred to a chemistry container.

17. Apparatus as set forth in claim 2 wherein said extraction means includes an extraction arm for successively communicating with each of said chemistry containers for extracting a predetermined amount of the formulated serum chemistries therein for analysis.

18. Apparatus as set forth in claim 17 wherein said extraction arm includes sealing means, drive means for successively positioning said sealing means into sealing engagement with each of the chemistry containers, a first passage in said sealing means for connecting the chemistry container sealed thereby to a source of fluid under pressure to pressurize the contents of said container, an extraction member in said sealing means having a second passage disposed therein so that said second passage is in communication with the contents of the chemistry container when the container is sealed, and means for connecting said second passage to a test receptacle for a predetermined time period whereby a predetermined amount of the chemistry container contents is induced to flow into said test receptacle.

19. Apparatus as set forth in claim 18 wherein said test receptacle comprises the flow cell of a spectrophotometer.

20. Apparatus as set forth in claim 1 wherein said chemistry conveyor means includes incubation means for selectively controlling the temperature of the contents of the chemistry containers.

21. Apparatus as set forth in claim 1 with the addition of cleansing means for cleansing serum from said second tube means after the predetermined amount of serum specimen has been deposited in one of the chemistry containers, said cleansing means including receptacle means disposed between said chemistry conveyor means and said serum conveyor means for receiving the serum cleansed from said second tube means.

22. Apparatus as set forth in claim 1 wherein said first fluid under pressure comprises a compressed gas.

23. Apparatus as set forth in claim 1 wherein said second fluid under pressure comprises a control liquid.

24. Apparatus as set forth in claim 23 wherein said control liquid is water.

25. Apparatus as set forth in claim 1 wherein the other end of said second tube means is connected to a valve member having said second and third valve means therein, said second valve means being selectively operable to connect said member to venting means and said third valve means being selectively operable to connect said member to said second fluid under pressure.

26. Apparatus as set forth in claim 1 wherein the other end of said second tube means is connected to a valve member having said second and third valve means therein, said valve member and second tube means being filled with said second fluid, said second valve means being selectively operable to vent said valve member to permit a portion of the second fluid in said second tube means to flow through said valve member and escape therefrom to allow a predetermined amount of the serum specimen to flow into said second tube means, said third valve means being selectively operable to provide flow of a predetermined amount of said second fluid through said valve member into said second tube means to cause a predetermined amount of the serum specimen in said second tube means to flow out of said second tube means into a chemistry container, whereby said second fluid is the only fluid that flows through said valve member.

27. Apparatus as set forth in claim 26 wherein said second fluid comprises a preselected liquid diluent, and said second valve means is selectively operable to cause a predetermined amount of said diluent to flow into the chemistry container along with said serum specimens.

28. Transfer apparatus for transferring a predetermined amount of a liquid specimen from a first container disposed at a pickup station to a second container disposed at a receiving station, comprising a transfer arm disposed generally between said pickup and receiving stations; drive means for driving said transfer arm between a position in communication with said first container and a position for communication with said second container; sealing means carried in said transfer arm for sealing said first container when said arm is in communication therewith; first tube means carried in said transfer arm and having one end communicating with said first container when said container is sealed, the other end of said first tube means being coupled through first valve means to a first fluid under pressure, said first valve means being selectively operable to admit said first fluid to said sealed container to pressurize said container; second tube means carried in said transfer arm and having one end for reception in the liquid specimen in said first container when said container is sealed, the other end of said second tube means being coupled through second valve means to venting means, said second valve means being selectively operable for a predetermined time period to allow the pressure in said sealed container to induce a predetermined amount of the liquid specimen to flow into said second tube means; and third valve means coupled between the other end of said second tube means and a second fluid under pressure, said third valve means being selectively operable for a predetermined time period when said transfer arm is in a position to communicate with said second container to cause a predetermined amount of the liquid specimen in said second tube means to flow into said second container.

29. Apparatus as set forth in claim 28 wherein the other end of said second tube means is connected to a valve member having said second and third valve means therein, said valve member and second tube means being filled with said second fluid, said second valve means being selectively operable to vent said valve member to permit a portion of the second fluid in said second tube means to flow through said valve member and escape therefrom to allow a predetermined amount of the specimen to flow into said second tube means, said third valve means being selectively operable to provide flow of a predetermined amount of said second fluid through said valve member into said second tube means to cause a predetermined amount of the specimen in said second tube means to flow out of said second tube means into a chemistry container, whereby said second fluid is the only fluid that flows through said valve member.

30. Apparatus as set forth in claim 28 with the addition of fourth valve means coupled between the other end of said first tube means and second venting means, said fourth valve means being selectively operable to release the pressure in the sealed container after the predetermined amount of the specimen has been induced to flow into said second tube means.

31. A method of preparing a succession of serum chemistries for analyzation, comprising the steps of conveying a plurality of serum specimens each contained in a specimen container along a first path; selecting particular ones of said serum specimens to be analyzed; successively transferring a predetermined amount of each of said particular serum specimens to individual chemistry containers in a chemistry conveying means, said transferring step for each of said selected serum specimens including the steps of sealing the specimen container containing one of the selected serum specimens, inserting a pressure tube into the sealed container and connecting said pressure tube to a first fluid under pressure to pressurize said container to a predetermined and substantially constant pressure level, inserting one end of a pickup tube into the serum specimen in said sealed container, venting the other end of said pickup tube through a venting valve for a predetermined time period to allow the pressure in the sealed container to cause a predetermined amount of the serum specimen to flow into said pickup tube, moving said pickup tube to a position for communication with one of said chemistry containers, and connecting the other end of said pickup tube through a first valve to a supply of a second fluid under pressure and selectively opening said first valve for a predetermined time period to allow said second fluid to flow into the other end of said pickup tube to cause a predetermined amount of the serum specimen in said pickup tube to flow into said chemistry container; and dispensing a predetermined and repetitive amount of a preselected reagent into each of said chemistry containers.

32. The method as set forth in claim 31 with the additional step of successively extracting a portion of the contents of the chemistry containers for analysis.

33. The method as set forth in claim 32 with the additional step of incubating the contents of the chemistry containers for a predetermined time period before said extracting step.

34. The method as set forth in claim 31 wherein said dispensing step includes the steps of maintaining a plurality of reagents under substantially constant pressure in individual reagent containers, each of said reagents having a delivery tube with one end received therein and the other end communicating through an individual valve member with successive ones of said chemistry containers, and selectively opening preselected ones of said valve members for predetermined time periods to allow selected and repetitive amounts of preselected ones of the reagents to successively flow into said chemistry containers.

35. The method as set forth in claim 31 wherein said transferring step is performed after said dispensing step.

36. The method as set forth in claim 33 wherein said transferring step is performed after said incubating step.

37. The method as set forth in claim 34 including the step of selectively opening said preselected ones of said valve members for a predetermined time period before reagent is delivered into the chemistry containers to allow the pressure in the reagent containers to cause flow of the preselected reagents into and through their respective delivery tubes and valve members to purge said tubes and valve members and to fill the same with reagent.

38. The method as set forth in claim 31 wherein said transferring step also includes the step of venting each particular sealed specimen container to release the pressure therein after the predetermined amount of the serum specimen therein has been induced to flow into said pickup tube.

39. The method as set forth in claim 32 wherein said extracting step includes the steps of successively sealing each of the chemistry containers, connecting said sealed chemistry container to a pressurized fluid to pressurize said container, inserting one end of an extraction tube into the contents of said pressurized chemistry container, connecting the other end of said extraction tube to venting means for a predetermined time period to induce a portion of the chemistry container contents to flow into and through said extraction tube into a test receptacle for analysis.

40. A method of transferring a predetermined amount of a liquid specimen from a first container at a pickup station to a second container at a receiving station, comprising the steps of sealing said first container, inserting a pressure tube into said sealed container and connecting said pressure tube to a first fluid under pressure to pressurize said sealed container to a predetermined and substantially constant pressure level, inserting one end of a pickup tube into the specimen in said sealed container, venting the other end of said pickup tube through a venting valve for a predetermined time period to allow the pressure in the sealed container to cause a predetermined amount of the specimen to flow into said pickup tube, moving said one end of said pickup tube to a position for communicating with said second container, and connecting the other end of said pickup tube through a first valve to a second fluid under pressure and selectively opening said first valve for a predetermined time period to allow said second fluid to flow into the other end of said pickup tube to cause a predetermined amount of the specimen in said pickup tube to flow into said second container.

41. The method as set forth in claim 40 with the additional step of venting said sealed first container to release the pressure therein after the predetermined amount of the specimen has been induced to flow into the pickup tube.

42. Apparatus for automatically preparing a succession of serum chemistries for analysis, comprising serum conveyor means for conveying a plurality of specimen containers each containing a serum specimen along a first path; chemistry conveyor means for conveying a plurality of chemistry containers along a second path; means for successively picking up a precise and predetermined amount of each of said serum specimens and depositing a preselected amount of each picked up specimen into one of said chemistry containers; a plurality of reagent dispensing heads each disposed adjacent said chemistry conveyor means; a plurality of liquid reagents each contained in an individual reagent container, each of said containers having a supply of a gas under pressure coupled thereto for pressurizing said containers to a predetermined and substantially constant pressure level; a plurality of reagent tubes each having one end received in one of said reagents and the other end disposed in one of said dispensing heads for communicating with successive ones of said chemistry containers as said chemistry containers are carried along said second path by said chemistry conveyor means; a plurality of reagent valves each coupled to one of said reagent tubes for selectively opening and closing said reagent tubes; and selection means for automatically opening selected ones of said reagent valves according to the particular analysis to be performed for a first predetermined time period to allow the pressure in the reagent containers associated with said selected reagent valves to cause flow of selected ones of said reagents out of their respective containers and into and through their respective reagent valves and tubes to flush said respective valves and tubes, and then for automatically opening said selected reagent valves for second and subsequent predetermined and repetitive time periods immediately after said first time period to allow the pressure in the reagent containers associated with said selected valves to cause flow of predetermined and repetitive amounts of said selected reagents out of their reagent containers and into successive ones of said chemistry containers to formulate serum chemistries.