Apparatus For Automatic Chemical Analyses

Abstract

Automatic chemical analyses apparatus includes a known turntable carrying a circumferentially arranged large series of (radial arrays of) reaction vessels, into each of which a sample is placed, and at other rotational positions of the turntable various "sample-treating" means are located (including means for adding reagents, means for sucking off all or part of the sample, stirring means for mixing the various contents of the vessels, and the like). The present apparatus includes a generally circular mounting plate, above the turntable and slidable on a stationary vertical guiding column (coaxial with the rotation axis of the turntable). At various circumferential positions along the mounting plate periphery, secondary radially extending projection plates, carrying the various different sample-treating devices are removably attached. Moving the entire mounting plate assembly up and down causes the various sample-treating devices to enter into and "clear" the various reaction vessels in the turntable. Certain additional devices, which are always utilized at a fixed point in the turntable cycle (e.g., means for placing samples in each of the vessels in a particular radial array) may be positioned in between the various peripherially attached secondary projections, without causing any problems of physical interference, since the mounting plate and its projections do not rotate, but only the underlying turntable with its reaction vessels. The various peripherially attached secondary "projections" may be disconnected and moved to different circumferential positions on the main-mounting plate (or projections carrying different sample-treating devices interchanged in an analogous manner), thereby affording great versatility as to the different types and timing of steps of analyses performed by the described apparatus.

Description

The present invention relates to apparatus for automatically carrying out chemical analyses comprising a turntable accommodating reaction vessels and sample-treating means adapted to be immersed into the reaction vessels from above.

In this connection the sample-treating means may be for instance, pipettes for sucking off or conducting the sample liquid, means for admixing reagents or even means for agitating the sample substance. These sample-treating means, during the working phase thereof, must enter into the reaction vessels and then be fully withdrawn from the reaction vessels during the advance movement of the turntable. With prior art apparatus of the type indicated the sample-treating means are individually movable and controllable. For a plurality of different sample-treating means such as become necessary for instance, when simultaneously carrying out several types of analyses in serial operation on one turntable, this will lead to constructional problems which are practically impossible to solve.

It is the object of the present invention to provide a simple constructional solution for the control of a plurality of upwardly and downwardly movable sample-treating means for automatic analytical apparatus operating with a turntable of the type previously mentioned.

According to the present innovation this object is attained by providing that above the turntable there is arranged a mounting plate on which the various sample-treating means are mounted and which is movably guided by its central hub on a guide column in a vertical direction and is upwardly and downwardly movable in synchronization with the turntable.

It is particularly advantageous if the mounting plate has a circular central portion to which plate-shaped radial projections, accommodating the sample-treating means, are attachable at different circumferential angular positions by means of detachable locking devices.

Then, by circumferentially displacing the projections relative the angular position of the sample-treating means mounted on each may be changed in a simple manner and therewith the moment of their becoming effective in the respective analysis cycle. In the spaces between these radial projections, further sample-treating means independent of the mounting plate, such as, for instance, sample supply or dosing pumps for distributing sample liquid from one sample vessel into several reaction vessels arranged in a radial array, may be arranged, without their operation colliding (i.e. interfering) with the functioning of the upwardly and downwardly movable mounting plate.

An embodiment of the present innovation will be hereinafter described with reference to the accompanying drawings, in which:

FIG. 1 shows a top view, partly in section, of an analytical apparatus according to the invention;

FIG. 2 shows a side view of the apparatus, also partly in section, and partly broken away.

The analytical apparatus (see FIG. 2) includes a turntable 1 having inserted therein circumferentially sample and reaction vessels 2 in radial arrays in a well-known manner. The turntable 1 constitutes a ring with a downwardly projecting rim 3. In the rim 3 there are supported rollers 4 with which the turntable 1 runs on a radial flange 5 of a stationary housing wall 6.

For supporting various sample-treating means there is provided a mounting plate 7 being upwardly and downwardly movably guided by its sleeve-shaped hub 8 on a central guide column 17. The mounting plate 7 has a circular central portion 9 to which plate-shaped radial projections 10 are attachable at different angular (i.e. circumferential) positions by means of detachable locking devices 11. These radial projections 10 carry the various sample-treating means, which may, for instance, be suction pipes 12 which are mounted to the radial projections 10 by means of fastening elements 13 (see FIG. 1). From the suction pipes hoses 14 extend. Further pipes 15 and hoses 16 may be used to flush the reaction vessels after the sample has been sucked off.

Changing the apparatus for adaption to different analytical objects may readily be accomplished by locking the radial projections 10 at another position on the circumference of the central portion 9. The angular position of the various projections with their own particular sample-treating means mounted thereon determines the moment in the analysis cycle, at which the respective sample-treating means become effective. The mounting plate 7 with the projections 10 does not rotate, and the turntable 1 rotates with periodically alternating speed or stepwise underneath this mounting plate about a common central axis.

In the periods of low speed or periods of inoperation of the turntable 1 the whole mounting plate executes a vertical (downward) stroke movement. Thereby, the sample-treating means are inserted into the respective reaction vessels disposed underneath at that moment. When the sample-treating means have fulfilled their function, the mounting plate will be raised, thereby completely to withdraw the sample-treating means from the reaction vessels so that the sample-treating means will not impede onward rotation of the turntable 1. Thereafter, the turntable 1 may be moved one step further, so that the respective next following radial array of reaction vessels 2 is moved underneath the sample-treating means.

The central guide column 17 is of substantially hexagonal cross section. It is surrounded by the hub 8. The hub 8 has provided therein three pairs of superposed rollers 18, 19, respectively offset with respect to each other by 120.degree.. These rollers each abut one side surface of the guide column 17. Thereby, the hub 8 with the mounting plate 7 is vertically movably guided on the guide column 17. As can be seen from FIG. 2, the hub 8 may be raised up into the position shown in dotted lines.

This raising and lowering of the hub 8 with the mounting plate 7 is effected via a vertical tooth rack 20 rigidly mounted to the hub 8 (see FIG. 1). This tooth rack is in mesh with a gear 21. The gear is driven via a worm wheel 22 and a worm 23, by means of a coupling comprised of a radial pin 24 on the shaft of the worm wheel 22 and an axial pin 25 at the gear 21. The gear 21 is axially disengageable against the action of springs 26, without getting out of mesh with the tooth rack 20. By axial disengagement of the gear 21, the coupling 24, 25 may be released, thereby rendering possible manual raising of the mounting plate after release of the coupling (also manually) in the event of failure of current or other failure which interrupts the drive via the worm wheel 22 and the worm 23. Control of the vertical extent of travel of the mounting plate is effected by limit switches 27, 28, 29 actuated by cams 30 on the hub 8.

Attachment of the radial projections 10 to the central portion 9 of the mounting plate 7 is effected by locking devices 11, as best seen in FIG. 2. The central portion 9 has a peripheral groove 31. Below the groove the central portion projects outwardly as at 32.

The projection 10 is inserted into the groove by means of an integral tongue 33 thereof, having a bore 34 therein. In a corresponding bore of the central portion 9 there is disposed a drop-in ball 35 being under the influence of a leaf spring 36. This drop-in ball engages into the bore 34 and acts on that edge of bore 34, shown on the left in FIG. 2. Thereby, the spring-urged ball 35 tends to draw the tongue 33 of the projection 10 leftwardly, thus towards the central portion 9. The correct circumferential angular position of the projections 10 is ensured by semicircular guide members 37 which are provided around the total circumference of the central portion 9 and cooperate with corresponding quadrant-shaped recesses 38 on the inner side of the projections 10 in order to align the projections 10. In the spaces between the projections 10, a sample dosing and distributing pump, for instance, as indicated at 39 in FIG. 2, may be separately movably mounted, both radially and upwardly and downwardly, as schematically indicated by the arrows directly above element 39.

Claims

I claim:

1. In an apparatus for automatically carrying out chemical analyses of the type comprising a rotatable turntable accommodating a plurality of series of circumferentially arranged reaction vessels being in the form of a circle which is concentric to the circle of each other circumferential series, and sample-treating means adapted to enter into the various reaction vessels in at least two different circumferential series from above, the improvement comprising:

a mounting plate comprising a circular portion, concentric with all said circumferential series of reaction vessels, for carrying said sample-treating means;

a central hub portion attached to said mounting plate;

a stationary vertical guide column for movably supporting said hub portion of said mounting plate, so as to movably guide said mounting plate above said turntable in a vertical direction;

and means for causing vertical movement of said mounting plate and its hub portion relative to said stationary guide column;

whereby said mounting plate and said various sample-treating means carried thereby may be raised and lowered relative to said turntable when said turntable is rotated to different circumferential positions, so that said sample-treating means may enter into and be moved out of said various reaction vessels regardless of the particular position on said circular portion of said mounting plate at which any said sample-treating means is carried.

2. An improved apparatus according to claim 1, in which:

said mounting plate comprises a central part surrounding said hub, said part having a circular exterior peripheral edge which comprises said circular portion;

said exterior circular portion comprises, at a plurality of peripheral locations, releasable attaching means;

at least one generally plate-shaped radial projection is provided, comprising connection means operatively cooperating with said releasable attaching means, so as to be attachable to said exterior circular portion of said mounting plate at any one of said plurality of peripheral locations;

and each said plate-shaped radial projection carries at least one said sample-treating means adapted to engage simultaneously at least two reaction vessels in different circumferential series;

whereby said sample-treating means may be placed at appropriate circumferential angular locations of said mounting plate and cooperate with at least one reaction vessel in each of any two of said peripheral series.

3. In an apparatus for automatically carrying chemical analyses of the type comprising a rotatable turntable accommodating circumferentially arranged reaction vessels, and sample-treating means adapted to enter into the various reaction vessels from above, the improvement comprising:

a mounting plate for carrying said sample-treating means;

a central hub portion attached to said mounting plate;

a stationary vertical guide column for movably supporting said hub portion of said mounting plate, so as to movably guide said mounting plate above said turntable in a vertical direction;

and means for causing vertical movement of said mounting plate and its hub portion relative to said stationary guide column, to raise and lower said sample-treating means relative to said turntable so that said sample-treating means may enter into and be moved out of said various reaction vessels;

said stationary vertical guide column having a regular even-numbered polygonal horizontal cross section;

and said hub portion carries at least three pairs of vertically superposed rollers, each pair offset from each other by an angle so as to abuttingly engage regularly distributed different flat side surfaces of said vertical guide column;

whereby said hub and its rigidly attached mounting plate is constrained from any movement in the horizontal plane, but can freely move in the vertical direction relative to said polygonal cross section, vertical guide column.

4. An improved apparatus according to claim 3, in which:

said regular even-numbered polygonal cross section is hexagonal;

and said rollers comprise three superposed pairs, each pair being offset with respect to each other by 120.degree.;

whereby each alternate or second surface of said hexagonal cross section, vertical guide column is engaged by one pair of said rollers.

5. An improved apparatus according to claim 3 in which:

a vertical toothed rack is rigidly attached to said hub portion;

a rotatable gear meshes with said toothed rack;

a driving worm drive is provided;

and means are provided for operatively connecting said worm drive to said rotatable gear;

whereby operation of said worm drive will cause rotation of said gear, thereby raising or lowering said mounting plate.

6. An improved apparatus according to claim 5, in which:

said operatively connecting means comprises a releasable connection of such construction that axial movement of said gear disconnects said worm drive from said gear;

whereby said mounting plate may be manually raised independently of said worm drive upon failure of said drive after such disconnecting axial movement of said gear.

7. An improved apparatus according to claim 5, in which:

switch-actuating cams are rigidly attached to said hub portion of said mounting plate;

and relatively stationary limit switches are engaged by said cams in the various raised and lowered positions of said mounting plate;

whereby the extent of vertical travel of said mounting plate is controlled by said various limit switches.