Automatic Sampler Apparatus Of Modular Construction

Abstract

A system for injecting sample fluids into an analyzer and processing the analysis data is disclosed. The system comprises a fluid sample analyzer, a sample storage module for a number of fluid samples, an injection module by which samples are injected into the analyzer, a data recording or processing device, and a control module for governing and sequencing the operation of the system. The injection module and the storage module are configured to permit alternate orientations to facilitate horizontal or vertical injection without disconnecting of interconnecting conduits.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the analysis of sample fluids and more particularly relates to systems for controlling the introduction of sample fluids into an analyzer.

2. Prior Art

Systems for supplying fluid samples for analysis by equipment, such as chromatographic analyzers, have been proposed by the prior art. Some prior art systems have employed a syringe for introducing a predetermined quantity of sample fluid into the analyzer equipment. Sample fluids to be analyzed were disposed in separate closed sample containers and successive individual fluid samples were removed from their containers, supplied to the syringe, and injected into the equipment.

It is imperative in most sample analyses that the sample fluid being analyzed be as free as possible from any type of foreign substance. Accordingly, the injection syringe was required to be thoroughly purged of one sample fluid and/or any residual cleansing solvent before a succeeding sample was placed in the syringe. The syringes employed for sample fluid injection were quite delicate because of the extremely small quantities of sample fluid they handled, e.g., quantities of from 5 - 50 microliters, this made manual operation and purging of the syringes both tedious and time consuming. Furthermore, when large numbers of samples were being successively analyzed, a skilled operator was required to attend the equipment and perform the tedious and repetitive task of purging and filling the syringe.

In order to increase the speed and efficiency of the analysis of multiple fluid samples, mechanized syringe handling systems were proposed. The purpose of such systems was to reduce the amount of operator time required in connection with the analysis procedures and to reduce equipment failures, e.g. the syringe breakage and damage which inevitably resulted from frequent handling.

The mechanized systems generally consisted of a supporting tray for sample containers and an injection syringe manipulating mechanism which functioned to enable removal of sample fluid from individual containers, injection of the fluid into the analyzer and purging of the syringe. The sample container trays were usually actuatable to index successive sample containers to a location from which fluid was transferred to the syringe.

While the prior art mechanized systems were effective in reducing the amount of operator time required to analyze fluid samples, several problems arose relating to convenient coordination between the mechanized systems and the analyzers into which the sample fluid was to be injected.

Prior art apparatuses for sample storage and injection were frequently designed to accommodate one particular type of analyzer. For example, some analyzers were constructed with horizontal sample inlets while others had vertical sample inlets and the orientation of the sample storage apparatus with respect to the injection apparatus was necessarily difficult from analyzer to analyzer depending on the analyzer constructions. Hence, in a facility having several differently constructed analyzers, the sample injection and storage apparatus could not always be interchanged between the analyzers.

SUMMARY OF THE INVENTION

The present invention provides a new and improved modular structure wherein fluid samples to be analyzed need not be loaded by the operator of the analysis system and confusion as to the identity of fluid sample analysis results is minimized; sample fluid injection equipment and associated sample flow conduits are purged by a controlled volume of purging fluid so that samples of fluid injected in the apparatus are nearly uniformly pure regardless of differences in sample fluid viscosity and/or volatility; the volume of sample fluid injected into the analyzer is accurately governed by adjustable dosage controls; damage to syringe-like elements of the system resulting from misalignment of sample containers or other fluid receivers and the syringe-like elements is avoided; and numerous different sample fluids can be analyzed automatically without requiring full time attendance of a skilled operator.

In a preferred and illustrated embodiment of the invention a sample analysis system is provided which comprises a sample analyzer, preferably a gas chromotograph, a sample injection module by which a sample of fluid to be analyzed is injected into the analyzer, a sample storage module which houses a number of discrete samples of fluid to be analyzed and which supplies sample fluid to the injection module, a sample analysis computer which may be programmed to partially govern operation of the system and to receive raw data from the analyzer concerning the analysis of the given sample of fluid, a recorder which is connected to the analyzer for producing graphic information concerning the analysis of given samples by the analyzer, and an electronic control module which governs operation of the components of the system.

The sample storage module is detachably connected to the injection module and sample fluid which is withdrawn from an individual container in the storage module is conducted into the injection module via a sample conduit. The injection module includes a syringe connected to the conduit which injects a predetermined dose of the fluid into the analyzer. Prior to the injection of a sample, the sample conduit and the injection syringe in the module are purged to remove residual fluid from a previous cycle of the system.

An important feature of the invention is the provision of a sample storage module and an injection module which are detachably fastened together and can be fastened together in various orientations with respect to each other without disconnecting electrical and fluid conduits extending between them. In one preferred embodiment, the storage and injection modules are interconnected by electrical and fluid flow conduits. The injection module and storage module are provided with alignable access openings through which the conduits extend when the modules are fastened together. Each module includes an alternate access opening for the conduits when the modules are fastened together in another orientation. The access openings are provided with slots which enable the conduits to be guided from one access opening through its associated slot into another access opening through its associated slot. The modules are then fastened together in the new orientation with the conduits extending through one or both of the now aligned alternate access openings.

This capability of the injection and storage modules enables the use of injection and storage modules constructed according to the present invention with many different analyzers and without requiring the various conduits between the modules to be disconnected when the modules are being oriented with respect to each other.

Other features and advantages of the invention will be apparent from the following detailed description of a preferred embodiment made with reference to the accompanying drawings which form a part of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a sample analysis system embodying the present invention with parts illustrated schematically;

FIG. 2 is a perspective view of a portion of the system of FIG. 1 with components shown in a different orientation;

FIG. 3 is a top plan view of an injection module forming part of the system of FIG. 1 with parts removed;

FIG. 4 is a cross sectional view seen approximately from the plane indicated by the line 5--5 of FIG. 3;

FIG. 5 is a plan view of a sample storage container module forming part of the system of FIG. 1 with parts removed and portions broken away;

FIG. 6 is a cross sectional view seen approximately from the line 9--9 in FIG. 5; and

FIG. 7 is a schematic diagram of a fluid pressure system contained within the injection and storage modules.

DESCRIPTION OF A PREFERRED EMBODIMENT

An automatic sample analysis system 10 embodying the present invention is illustrated in FIG. 1 as comprising a sample analyzer 12, which may be, for example, an apparatus for analyzing a fluid sample by liquid or gas chromotography; a sample injection module 14 by which a sample of fluid to be analyzed is injected into the analyzer 12; a sample storage module 16 which houses a number of discrete samples of fluid to be analyzed and which supplies sample fluid to the injection module; a sample analysis computer 18 which is programmed to partially govern operation of the system and to receive raw data from the analyzer concerning the analysis of a given sample of fluid and to process that data into a desired useable form; a recorder 20 which is connected to the analyzer for producing graphic information concerning the analysis of given samples by the analyzer; and an electronic control module 22 which generally governs the operation of the remaining components of the system 10.

In brief, the system 10 operates in the following manner: The injection module and sample storage module are connected to each other in a desired orientation, for example, in the orientation shown in FIGS. 1 or 2 and are detachably connected to the analyzer 12, which may be of any suitable or conventional type or construction, and a number of containers of sample fluid are disposed in the storage module. Automatic operation of the system is then initiated by the operator which results in a predetermined quantity of sample fluid from one container in the storage module 16 being extracted and delivered to the injection module 14 from which a predetermined quantity of the sample is injected into the analyzer 12. The analyzer 12 processes the sample fluid and data resulting from the analyzer process is fed to the computer 18 and/or the recorder 20. At the same time, information concerning the identity of the sample injected into the analyzer is supplied to the control module from the storage module and thence to the recorder and computer so that the data being obtained from the analyzer is identified with the particular container from which the sample was removed. After the first fluid sample has been analyzed, sample fluid from a second container is directed from the storage module to the sample injection module and the analysis process is repeated. When all of the samples have been analyzed, the operation of the system 10 is automatically terminatable.

Prior to the injection of each fluid sample into the analyzer, the flow passageways through which the sample passes from the storage module into the analyzer are purged to remove substantially all traces of the preceding sample fluid from the passages prior to the introduction of the next succeeding sample to the analyzer. Purging is conducted using the next succeeding sample fluid itself or using a suitable solvent and then the next succeeding sample fluid so that the possibility of contaminating any given fluid sample by the preceding sample or the solvent is minimized. The purging solvent is contained by the storage module like the samples and is introduced into the passages to be purged. The sequence of operation of the system 10 is governed by the control module in cooperation with the computer.

It should be appreciated that the brief description of the operation of the system 10 has been simplified and generalized in order to provide an overall understanding of the functions and interrelationships of the various modules and components of the system 10. The various modules and components of the system 10 are described separately below.

THE INJECTION MODULE 14

The injection module 14 comprises a support frame 30 which supports a syringe carriage assembly 32, a carriage actuator 34 and a waste receiving system 36. The syringe carriage assembly 32 includes a sample injecting syringe, described in detail presently, which is movable by operation of the carriage actuator 34 to inject a predetermined quantity of sample fluid into the analyzer 12 as well as to inject purging fluid into the waste receiving system 36. The injection module 14 is illustrated in FIG. 3 of the drawings.

Referring particularly to FIG. 3, the frame 30 is illustrated as including side panels 40, 42, opposite end walls 44, 46 extending between the side panels, and a base section 48 extending from the end wall 46 between the side panels 40, 42. A pair of cylindrical guide rods, or ways, 50 extend between the end walls 44, 46 parallel to the side panels. The end wall 44 mounts along the face of the analyzer 12 by interconnection of the end wall 44 to the analyzer by suitable connectors (not shown). The end wall 44 defines an opening 52 which is aligned with an analyzer sample inlet which is shown in part in FIG. 4 at 12a. The sample inlet 12a is provided with an inlet port through which the needle or canulla, of the injection syringe extends when a sample is being injected into the analyzer. The inlet sample port is covered by a septum as is conventional, so that in order to inject a sample of fluid into the analyzer the syringe needle must pierce the septum covering the analyzer inlet port.

The side panels 40, 42 extend away from the analyzer 12 and each defines an access port 56 and connector openings 58. Normally fluid and/or electric conduits extend through one or the other of the ports 56 from the storage module 16 depending upon which of the side panels 40 or 42 is engaged with the storage module. The connector openings 58 function to enable detachable connection of the storage module to the injection module by screws or other suitable fasteners which extend between the modules.

Alternatively, slot 60 enables repositioning of the storage module from one side panel of the frame 30 to the other side panel without requiring disconnection of the conduits extending between the modules during the repositioning if the conduits are guided from one access opening in the storage module through the associated slot 60, or to the other access opening or slot in the storage module through its associated slot 60 without disconnecting the conduits from the injection module. Repositioning of the storage module with respect to the injection module might be occasioned where the storage and injection modules are utilized in connection with various analyzers having different physical configurations. One such repositioning of the modules is illustrated by FIGS. 1 and 2. In the configuration shown by FIG. 1, the modules are attached to an analyzer 12 having a horizontal sample inlet while in FIG. 2 the same modules are repositioned and connected to an analyzer 12' having a vertical sample inlet.

Removable cover panels 62, 64 are connected to the frame 30 to shield the internal components of the injection module 14 when in use, and are removed to enable access to these components for servicing and maintenance. One or both cover panels 62, 64 are also removed when the injection module is repositioned with respect to the storage module to enable manipulation of the interconnecting conduits from one access opening to the other as described above. The cover panels 62, 64 are illustrated in FIGS. 1 and 2.

THE STORAGE MODULE

The storage module 14 supports a plurality of separate containers 240 for fluid samples and purging solvents and defines an extraction station 250 at which a fluid sample or purging solvent is extracted from a respective container and is directed to the injection module 14. The individual containers 240 are supported by a plurality of the sample supporting tray members, or racks, indicated by the reference characters 252-255 (see FIG. 5). The trays, or racks, are individually removable from the storage module 16 with their associated sample containers. An actuator assembly 258, forming a part of the module 16, moves the container supporting trays in carrousel fashion so that individual containers are successively moved to the extraction station 250 from which the contents of the container at the extraction station can be removed and directed to the injection module.

Referring now to FIG. 6, the storage module 16 comprises a support frame 260 which is defined by a peripherally extending skirt 262 and a circular base plate 264 connected to the skirt. Side panels 266, 268 extend perpendicularly with respect to each other and generally tangentially with respect to the support base portion 264 and skirt 262 to define a projecting corner of the storage module. The extraction station 250 is located at the projecting corner of the module and the trays 252-255 are circularly arranged over the support base 264.

The sample supporting tray members 252-255 are, in most respects the same, and only the tray 253 is described in detail to the extent that the trays are identical. The tray 253 is shaped to approximate a frustum of a 90.degree. circular segment having a circularly curved outer wall 270, radially extending side edges 272, 274 and a radially inner edge 276 which extends between the side edges. A segmental radially inner tray body 280 extends between the edges 272, 274, 276 and terminates in a circular wall portion 282. The edges of the tray member are defined by lips which project from face of the body 280 and these lips, along with radially extending webs 284, rigidify the tray body portion 280. A pair of cylindrical bosses 285 extends from the body 280 beyond the webs 284. The bosses provide a detachable driving connection with the tray actuator assembly 258 as is described in greater detail presently.

A radially outer tray body portion 286 extends from the wall 282 and is recessed from the body 280. The outer tray body portion 286 terminates in the circumferential wall 270 and is rigidified by integral webs 292 which extend radially outwardly from the wall 282 flush with the inner tray body portion 280.

A circumferential series of sample container pockets 296 (preferably 15 pockets for accommodating 15 separate containers) is disposed circumferentially about the periphery of the outer tray body 286. The pockets 296 are defined by semi-circular recesses 298 formed in the tray wall 270 and semi-circular faces 300 formed on projecting lugs 302 at the radially outer ends of the webs 292. The recesses 298 and faces 300 are positioned with respect to each other so that the container in each individual pocket is maintained accurately positioned in the pocket and constrained against tipping, even if the tray should be vertically oriented.

The container support actuator 258 comprises a turntable assembly 310 to which the individual trays 252-255 are detachably connected and a turntable drive mechanism 312 by which the assembly 310, and the attached trays, can be rotated with respect to the frame base 264. The assembly 310 comprises a support shaft 314 which extends through the frame base 264 and is supported for rotation about an axis 315 by a bearing unit 316 connected to the frame base. The projecting end of the support shaft 314 carries a circular tray support member 320 which is fixed to the shaft 314 for rotation about the axis 315 and which defines four pairs of circumferentially spaced locating holes 321. A drum-like member 322 is disposed between the tray support 320 and the frame base 264 and is fixed to the shaft 314 for rotation with it.

A tray locking assembly 324 is disposed beyond the tray support 320 from the drum 322 and functions to permit the individual sample supporting trays to be connected to and locked in place on the tray support member.

The locking assembly comprises a cylindrical body 330 which is fixed to the end of the shaft 314 for rotation about the axis 315. Four shouldered holes 332 are formed in the body 330 at locations spaced 90.degree. apart about the axis 315, with the holes extending generally parallel to the axis. A circular retainer plate 334 is connected to the body 330 to close the holes 332. Each of the holes 332 supports a shouldered detent pin 336 and a helical compression spring 338 which reacts between the detent pin 36 and the retainer plate 334 so that the projecting end of the detent pin is urged from the body 330 towards the tray support 320.

Trays are inserted and locked in placed in the assembly 310 by cocking the tray slightly with respect to the support member 320 and inserting the inner edge 276 of the tray between the support member 320 and the body 330 of the locking assembly. The end of the detent pin 336 is rounded so that the detent pin is forced into its shouldered hole 332 against the force of the spring 338 as the tray is slid radially inwardly along the support member 320. When the locating bosses 285 are aligned with one pair of the locating holes 321 the tray is cocked downwardly so that the bosses 285 extend through the associated locating holes 321. At this juncture the webs 284 of the tray are engaged along the face of the support member 320 and the detent pin 336 is firmly engaged with the tray body portion 280 to maintain the tray member in contact with the support member 320. The bosses 285 cooperate with their respective locating holes to enable the transmission of drive from the rotatable support member 320 to the tray.

The drive mechanism 312 includes a reversible electric motor 340 having a gear reduction (not shown) connected to its rotor shaft. An output shaft of the gear reduction (not shown) extends through the frame base 264 and an output pulley 344 is connected to the projecting end of the gear reduction output shaft. A drive belt 346 is reeved about the pulley 344 and the drum 322 so that drive from the motor 340 is transmitted to the turntable assembly 310 and thence to the individual trays supported by the turntable assembly.

The containers 240 may be of any suitable construction but in the illustrated embodiment are glass vials which fit snuggly into the pockets 296. The containers 240 have a capacity of several milliliters of fluid and each container is closed by a septum 241 which is carried by a removable cap 348.

An important feature of the invention resides in the ability of the storage module 16 to receive from one to four trays of a large number of support trays which may be loaded with sample containers at locations remote from the actual location of the system 10. As an example, the system 10 can be a central analyzer system at which a primary analyzer system serves a number of separate laboratories. Sample trays can be loaded with sample and/or solvent containers in the laboratories and forwarded to the analyzer system, thus relieving the analyzer operator from the task of loading the sample trays and recording the identity of each sample and its position in the tray. Each of the trays is provided with indicia indicating the identity of the tray, by a decimal number as well as indicating, by decimal numbers, the identities of the individual pockets in the tray. When the trays are loaded at their individual laboratories, the personnel loading the trays need only record the tray or rack number and the substance in each container along with the associated pocket number. The operator of the analyzer need not be involved in this process. In the preferred embodiment, the module 16 can handle up to four of 16 separate sample trays at any given time.

The turntable assembly 310 moves the trays to position successive container locations at the extraction station 250. Fluid in a container at the extraction station is removed by a syringe-like dipper tube assembly 352 (which is described in detail below) and is directed to the injection module 14. The storage module 16 provides a container locating assembly which functions to precisely align the containers at the extraction station with the dipper tube assembly so that the dipper tube assembly is not damaged from being advanced into engagement with a misaligned container.

As is best seen in FIG. 6, the dipper tube assembly 352 comprises an extraction syringe needle assembly 430, an associated pneumatic fluid purging system 432 (see FIG. 7) and an extraction syringe actuator assembly 434. The actuator assembly 434 comprises a syringe needle support plate 436 which is connected to a single acting pneumatic ram including a cylinder 440 connected to the frame by a supporting bracket 442 and a piston rod 444 extending between the cylinder 440 and the support plate 436. A radially inwardly projecting plate end 446 carries the needle assembly 430 for reciprocating motion towards and away from a container 240 at the extraction station. The plate 436 is connected to guide rods 450, 452 which extend through bores in the bracket 442 to guide the motion of the plate and the needle assembly as the plate is reciprocated by the ram 438. The guide rod 450 is surrounded by a helical compression spring 454 which reacts against the syringe support plate 436 to urge the piston rod 44 towards its fully extended position. When the piston rod retracted the plate and needle assembly 430 move towards the container and the needle assembly is thrust into the container through its system.

In the preferred and illustrated system, the injection syringe has an internal volume of about 10 microliters and the sample conduit 466 has an internal volume of about 10 microliters. It has been found that purging such a system with a flow of fluid equal to about 10 times the combined syringe and conduit volumes reduces the quantity of residual material in the purged volume to consistently low levels, e.g., to less than 0.01 percent by volume. Accordingly, in the preferred system, the 100 microliter accumulator, charged to 25 psig, is effective to produce a purging volume of solvent and/or sample fluid of about 200 microliters.

Some sample fluids have high vapor pressures at room temperature and if the accumulator were discharged into a container of such a fluid, the partial pressure of the vapor combined with the PV energy of the purging gas could cause an excessive quantity of the fluid to be forced from the container. Accordingly, in the preferred embodiment of the invention, after the needle assembly has been inserted into a container, the vent valve 506 is opened to communicate the container to atmospheric pressure via the needle 470, the conduit 520 and the valve 506. The valve 506 is operated by a solenoid 506a which is energized and deenergized from the control module 22.

After the vent valve 506 is opened to vent the container, it is reclosed and the container volume is substantially at atmospheric pressure. The control valve 504 is then actuated to discharge the accumulator into the container so that a predetermined controlled pressure differential is applied across the sample fluid, the fluid conduit 466 and the injection syringe assembly 72. In the preferred embodiment of the invention the control module functions to allot a one minute period during which purging is accomplished. Purging is normally completed within the alloted time.

Where a sample fluid has a relatively high viscosity, (e.g., greater than 1 cp) its flow resistance is relatively great and a single discharge of the accumulator may not provide sufficient energy for a complete purge during the alloted one minute purging period. In such circumstances the operator can condition the control module to operate the control valve 504 to discharge the accumulator a second time during the purging period, e.g., after 30 seconds have elapsed. The additional PV energy thus supplied to the container compensates for the high fluid viscosity. After purging is completed the dipper tube assembly is withdrawn from the container. Just as the dipper tube begins to withdraw, the control valve 504 is again operated to discharge the accumulator. The accumulator discharges partly into the container and partly to atmosphere as the dipper tube needle assembly is moved from the container septum. The portion of the discharge into the container is effective to provide an air pocket at least in the dipper tube needle 460. This reduces the chance that a drop of fluid from a preceding sample container can drip into a succeeding sample container during the dipper tube insertion.

Referring further to FIG. 7 the injection and storage modules 14, 16 are shown schematically by broken lines along with the various elements of the pneumatic system for operating the actuators in the modules.

As illustrated by FIG. 7 the injection syringe carriage actuator 34 is communicated to a solenoid control valve 530 in the storage module by a conduit 532. The control valve 530 is in turn connected to the pressure manifold 510 by a conduit 534. The valve solenoid 530a is energized and deenergized from the control module 22 to control operation of the valve. When the actuator 34 is operated to advance the syringe carriage towards the analyzer inlet 12a or the waste receptacle, the valve 530 is operated to direct high pressure air to the actuator 34. The carriage is retracted by operating the valve 530 to vent the actuator 34 so that the actuator return spring retracts the carriage.

The double acting plunger actuator 132 is communicated to the manifold 510 at one end via a conduit 540, a control valve 542 and a conduit 544. The opposite end of the actuator 132 is communicated to the manifold via a conduit 546, a control valve 548 and a conduit 550. The valves 542 and 548 each are operated by solenoids 542a, 548a slot which are wired to the control module. The valves 542, 548 are constructed like the valve 530 to either supply high pressure air to their respective ends of the actuator 132 or to vent the actuator, depending on energization of the solenoids. When both valves direct pressurized air to the actuator 132 the plunger is positively positioned by the actuator, as noted previously. This operation of the valves only occurs when the cross bar 140 engages one or the other of the dosage stops 134, 136, which are schematically illustrated in FIG. 7, to enable retraction of the dosage stop element.

The single acting dipper tube actuator 434 is communicable to the manifold 510 via a conduit 554, a control valve 556 and a conduit 558. The control valve 556 includes a solenoid 556a wired to the control module 22. The valve 556 is constructed and functions the same as the valve 530.

As is apparent from FIG. 7 the pressure conduits 532, 540 and 546, as well as the sample fluid conduit 466 all extend between the storage and injection modules. Additionally, as noted above, the electric conductors for the dosage stops 134, 136 and the waste system solenoid 214 also extend from the storage module to the injection module.

As illustrated in FIGS. 2 and 6 the storage module frame side panels 266, 268 each include an access opening 560, 562, respectively, through which the various conduits and wires extend to the injection module. When the storage and injection modules are fastened together one or the other of the access openings 560, 562 is aligned with an injection module access opening 56, with the conduits and wires extending through the aligned opening.

In some circumstances it is desirable to be able to reorient the storage module with respect to the injection module in such a way that the conduits and wires all extend through the same injection module access opening 56 but through a different access opening in the storage module. In order to accommodate this type of reorientation each storage module access opening has an associated guide slot 564, 566, (FIG. 6) respectively, which opens into the access opening and extends to a side edge of the associated frame side panel 266 or 268. When the storage module is reoriented with respect to the injection module the conduits and wires can be guided from one access opening through the slots 564, 566 and to the other access opening without requiring disconnection of any of the conduits or wires from either module.

The storage module is preferably provided with a removable cover 570 (see FIGS. 1 and 2) having a transparent cover portion 572 extending over the turntable and container trays and a second cover portion 574 extending over the extraction station 250. The cover portion 572 is hinged to the portion 574 so that it may be lifted to enable quick removal and replacement of the trays. The entire cover 570 can be lifted from the storage module to permit access to the extraction station for servicing as well as to permit guiding of the conduits and wires from one access opening to the other.

The sequence control circuitry 600 functions to cause the system components to perform the following steps:

1. The syringe carriage 70 is advanced to thrust the needle 94 into the waste receiver 200;

2. The actuator 132 for the plunger 92, which is initially in its fully depressed position, is subjected to fluid pressure to urge the plunger toward the depressed position;

3. The dipper tube assembly 430 is thrust into the sample container at the extraction station;

4. The container vent valve 506 is opened to vent vapor pressure from the container;

5. The vent valve 506 is reclosed;

6. The accumulator control valve 504 is operated to discharge the accumulator into the container;

7. The syringe plunger actuator 132 is operated to withdraw the plunger 92 to the side arm port;

8. A dwell period is provided during which purging is of the sample conduit 466 and the syringe assembly 72 is completed;

9. The dipper tube assembly is raised from the container;

10. The accumulator is discharged via the control valve 504 to place an air pocket in the dipper tube needle 460;

11. A dosage stop solenoid is energized to provide a preset dosage stop;

12. The plunger 92 is depressed to the dosage stop thus closing the syringe side arm port;

13. The syringe carriage is retracted to withdraw the needle 94 from the waste receiver;

14. The waste receiver is actuated to its retracted position;

15. The carriage 70 is advanced to thrust the needle 94 into the analyzer inlet 12a;

16. The pressure across the piston of the plunger actuator 132 is equalized;

17. The dosage stop solenoid is deenergized to retract the stop element;

18. The plunger 92 is driven into the syringe barrel to its limit of travel;

19. The syringe carriage 70 is retracted to withdraw the needle 92 from the analyzer inlet;

20. The waste receiver 200 is repositioned between the needle 92 and the analyzer inlet;

21. The plunger actuator is deenergized.

The enumerated steps each occur immediately after the preceding step except for steps 6 and 10 which preferably require a four second delay prior to the succeeding step. This is due to the time required to completely discharge the accumulator and each time the control valve 504 is actuated to discharge the accumulator the four second delay period follows. So far as step 10 is concerned it should be noted that since the dipper tube assembly is withdrawn from the container as the accumulator discharges, the accumulator discharges directly to atmosphere during part of the four second period. The energy supplied to the container is not sufficient to remove all of the sample fluid from the conduit 466.

The time delay periods are determined by a clock circuit 620 which provides timed pulses to the sequence control circuit 600.

When a viscous sample fluid is to be injected the operator can enable a high viscosity circuit 622 which conditions the sequence control circuit 600 to discharge the accumulator into the container a second time during the dwell period of step 8.

When the sample is actually injected into the analyzer the sequence control circuit 600 sends an appropriate confirmatory signal.

When the fluid is injected the sequence control circuit provides a signal to the logic circuitry 584, the injection counter 604, an analysis time clock circuit 630, an auxiliary time clock circuit 632, the recorder 20, and to an integrator associated with the recorder.

The logic circuitry 582 initiates operation of the computer via the enabling circuitry 584 so that data from the analyzer is processed by the computer. The injection counter receives and stores the injection signal for comparison with the required number of injections per container selected by the circuitry 602. The signal to the recorder results in an injection mark being placed on the graph produced by the recorder.

Some analyzers have two analyzer inlet ports and with such an analyzer it is possible to provide an injection module 14, a storage module 16 and a control module 22 for each inlet port. The operation of these separate units can be interrelated by interconnecting the logic circuits of each control module. This interconnection allows one unit to be readied for an injection while a sample from the other unit is being analyzed and vice versa.

While a single embodiment of the present invention has been illustrated and described in considerable detail, the invention is not to be considered limited to the precise construction shown. Numerous adaptations, modifications and uses of the invention may occur to those skilled in the art to which the invention relates and it is the intention to cover all such adaptations, modifications and uses which fall within the scope or spirit of the appended claims.

Claims

We claim:

1. In a system for injecting fluid samples into a fluid receiver;

a. a fluid sample storage module comprising:

i. a sample fluid support for a plurality of separate fluid samples,

ii. sample fluid extraction means defining a station along said sample fluid support at which fluid is extracted from said sample fluid support; and

iii. laterally spaced side walls having a corner intersection, each said side wall defining first and second spaced access means located in the vicinity of said extraction station, said first access means being a hole in said side wall and said second access means being a slot extending to the edge of said side wall;

b. an injection module for receiving sample fluid from said storage module and comprising;

i. sample fluid injection means for directing a quantity of fluid into an analyzer;

ii. actuating means for controlling operation of said injection means; and

iii. at least a wall defining an access opening;

c. structure defining a fluid sample conduit extending between said modules for directing sample fluid from said storage module to said injection module through said second access means in a said side wall of said sample storage module and through said injection module access means; and

d. connecting means for detachably connecting said modules together with said third access opening aligned with one of said first or second access openings, said conduit structure extending between said modules through said aligned access openings.

2. In a system as claimed in claim 1 wherein said injection module includes a second wall defining further injection module access means, said injection module access means in each said first and second wall being a hole and a slot, each said slot extending to said injection module wall edge.