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Publication numberUS3722790 A
Publication typeGrant
Publication dateMar 27, 1973
Filing dateJul 30, 1969
Priority dateJul 30, 1969
Publication numberUS 3722790 A, US 3722790A, US-A-3722790, US3722790 A, US3722790A
InventorsS Natelson
Original AssigneeRohe Scientific Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sequential centrifugal treatment of liquid samples
US 3722790 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

mu 7 w 2, 7 n2 3 M HM HM m $1 n 9 WW 3 P S 0 An a t S w m B Q Mn N [54] SEQUENTIAL CENTRIFUGAL TREATMENT OF LIQUID SAMPLES 9/1964 Anthon...... 10/1969 Baruch [75] Inventor: Samuel Natelson,Chicago, Ill.

Rohe Scientific Corporation, Santa Ana, Calif.

[73] Assignee:

Primary Examiner-James R. Boler I Assistant Examiner-George H. Krizmanich [22] Flled' July 1969 Att0meyGeorge B. Oujevolk [21] Appl. No.: 845,992

ABSTRACT System for the sequential treatment of liquid chemical samples comprising the steps of depositing the samp s ina series of top-like containers having a peripheral side chamber. The containers are placed on a belt and moved past a centrifugal field wherein the containers are rotated. The containers are then removed at a ter- Reterences Cited minal zone and the heavier sample component UNITED STATES PATENTS remains in the side chamber as the lighter components flow to the bottom of the container. 2/1966 8/1965 Unger.................................233/26 X Drucker X 18 Claims, 24 Drawing Figures ru um PD A sm STAT] O N PATENTEUHARZYISYE 3,722,790

sum 2 OF 8 H9 2d FIG. 20



' ATTORNEY PATEf-H'Eflzxwznsn SHEETHDF a 62 FIG. 3c





, ATTORNEY SEQUENTIAL CENTRIFUG AL TREATMENT OF LIQUID SAMPLES BACKGROUND OF THE INVENTION fact that the workload of samples processed varies considerably over working periods.

Numerous attempts have been made to design a laboratory where blood or urine, or some other biological fluid can be processed automatically. No complete system has been developed. For example, for many chemical determinations a sample of serum needs to be prepared from the blood. The blood is then centrifuged and the serum sampled. The process of placing large numbers of tubes in a centrifuge, waiting for the centrifuge to accelerate, operating at high-speeds and then coming to rest, usually takes approximately 30 minutes. To this must be added the time required to load the centrifuge and unload it.

Once the serum is obtained the automatic instrument is loaded. Some commercial instruments do not have the capability of removing proteins. The number of tests that can be performed is then limited to those where protein does not interfere. Other instruments remove protein by adding a protein precipitating reagent and filtering. In this case a large sample is needed and only a small portion of the filtrate is obtained. Other systems remove protein by dialysis. In these cases only a small percentage of the ingredient being tested dialyzes through, limiting the sensitivity and accuracy of the procedure, so that new methodology has to be found to fit the instrument. In many cases compromise has to be made with accuracy and specificity.

The present invention solves these problems, making practicable a completely automated laboratory using conventional procedures. It permits the processing of the sample collected from the patient directly without pretreatment or handling. It readily permits any number of analyses to be performed automatically and the results may be printed on cards or charts depending upon the desire of the operator.

The present system becomes possible because of the development of an automatic centrifuge which serves to separate red cells from blood automatically and remove the serum from said cells. It also permits the automatic precipitation of proteins and their removal by automatic centrifugation.

Before describing the system herein contemplated, it is first necessary to see what tests the system is to perform, and, since the system contemplated is particularly useful for processing blood samples, the tests relating to blood will be described.

It goes without saying that for some tests this apparatus is not required. Such blood tests have been described in the Natelson, U. S. Pat. No. 3,260,413. In the tests performed by the system of the present invention the sample cannot be processed in the manner described in the aforesaid Natelson, U. S. Pat. No. 3,260,413 without first separating some of the components in the sample.

The overall procedure can be described as follows: After separating serum or plasma from the cells, one samples the separated serum with an autodilutor. This is an instrument which samples the serum and ejects it with a reagent or diluent. Autodilutors, of varying design, are available commercially.

After separating the serum from the cells, a series of samples can be taken from the serum and processed to determine the various components. In some cases, the autodilutor adds a protein precipitant. The mixture is then centrifuged, and an aliquot is taken from the supernatant, by an autodilutor. Various reagents are added to produce a color so as to assay the various components.

Thus, one can see that with an automatic centrifuge the technician places the blood sample, contained in a special container hereinafter described, into a holder called a trunnion cup. The sample, e.g., blood, is centrifuged automatically. The centrifuged blood moves down a line on a belt where autodilutors remove samples to do different tests. In some cases, no further reagent need be added and the diluted serum is assayed directly. In other cases, a sequence of sampling, centrifuging and further sampling is done. Examples of the various types of components of blood which can be analyzed by a general system of the type described, are listed below.

I. Tests where no protein needs to be removed from the serum:

In these cases, after passing the automatic centrifuge the separated serum is sampled and processed as indicated.

a. Protein- Serum sampled, biuret reagent added and assayed colorimetrically.

b. .Na and K- diluted serum aspirated photometer.

c. Chloridediluted, serum titrated amperometrically.

d. CO serum aspirated into an automated microgasometer.

e. Oxygen, and Nitrogen serum sample taken and processed in a gas chromatograph.

f. Ca and Mg diluted serum aspirated into an atomic absorption instrument.

II. Tests for components where protein is precipitated before adding the color developing reagents.

a. Glucose, by heating with alkaline copper, reagent.

b. Urea, by the diacetyl reaction.

c. Creatine, by alkaline picric acid.

d. Uric acid, by reduction of phosphotungstic acid.

III. Enzyme Tests:

In these cases the serum is sampled and a substrate added. Subsequently reagents are added to develop a color or a protein precipitant is added. The samples are centrifuged and then reagents are added for purposes of identification of the products.

a. Tests where a second centrifuging is unnecessary:

l. Lactic Dehydrogenase 2. The and S6? transaminases 3. Alkaline and acid phosphatases 4. Lipase 5. Creatine phosphokinase Tests where a protein precipitate is added after incubation with substrate: 1. Arginase 2. Argininosuccinic acid lyase (ASAL) 3. Amylase into flame The data accumulated at various stations can be accumulated on a tape and fed into a print out device which can supply the data in the form desired with conventional instruments. A panel, with proper keys can guide the specimen through the system. For example, if only sugar determination is desired on the sample, then activation of this key will make inoperative all sampling positions except that for sugar. On the other hand if all tests are desired, pressing the proper key will activate all stations for the sample.

From the foregoing description, it will be noted that present technology permits the carrying out of many of the steps described. However, one step cannot be carried out. That step is the automatic centrifuging of the sample in a continuous manner. The problem is to centrifuge the sample and have it move out of the centrifugal field. In order to perform this task one can conceive of an instrument which would perform the following steps mechanically.

1. Place a tube in a centrifuge.

2. Slowly accelerate the specimen to running speed (e.g. 3000 r.p.m.).

3. Run the rotor at top speed 4. Decelerate the rotor.

5. Remove the specimen from the rotor.

While there would be no difficulty in designing such an instrument with present technology, the problem is that such a cycle would take 30 minutes and specimens would be available at two per hour. If a large number of specimens were available such an instrument would load, for example 60 specimens, go through the cycle and at the end of say 45 minutes have all 60 unloaded. Unfortunately, laboratories are faced with the complex problem of having at some times only one specimen and at others as much as 300. The problem is to provide an instrument which will process the samples sequentially. Under such a system the samples would be loading at one per 30 seconds and unloading at one every 30 seconds. One would wait 20 minutes for the first specimen but subsequently they would be leaving at I20 per hour so that after a delay of 20 minutes the analytical results would be available at 120 blood samples per hour with as many as 40 results on each blood sample.

The problem is. further complicated by the fact that blood is often taken with heparin, in which case the blood does not clot. On centrifuging, the packed cells are relatively loose. Further, if the serum is allowed to remain in contact with the cells for any length of time, diffusion of, for example, potassium ion from the cell (concentration 90 mEq/L) into the plasma (concentration 5 mEq/L) destroys the value of the determination. Glycolysis going on in the cell also metabolizes the glucose in the plasma, lowering the result. This requires that the centrifuge operation be done not once but twice. The blood is centrifuged, the serum is poured off, recentrifuged and poured off again to remove all cells.

If the blood is clotted, the cells will pack more efficiently and sometimes it is possible to pour off clear serum, if one is willing to sacrifice some serum over the clot.

From the foregoing description it is quite apparent that the bottleneck in any completely automated system is in the centrifugal step. This invention solves for minutes.

this problem. This invention describes a practical procedure and instrumentation for continuously centrifuging samples in sequence at a rapid rate.

The invention as well as the objects and advantages thereof will become more apparent from the following detailed description when taken together with the accompanying drawing, in which:

FIG. 1 is a schematic and block diagram of the system contemplated herein;

FIG. 2a is a perspective view of one type of sample container contemplated herein;

FIG. 2b is a side view of the sample container depicted in FIG. 2a;

FIG. 20 shows a side view of another type of container contemplated herein;

FIG. 2d illustrates a side view of still another type of container contemplated herein;

FIG. 2e shows a perspective view of yet another type of container contemplated herein;

FIG. 2f is a side view of the container shown in FIG. 2e;

FIG. 2g is an illustration of the action that takes place within the container shown in FIG. 2a while that container is in operation;

FIG. 2h is an illustration of the action that takes place in the container shown in FIG. 2a after the operation illustrated in FIG. 2g;

FIG. 2i is an illustration of another container contemplated herein;

FIG. 3 is a longitudinal perspective view of an apparatus contemplated herein to perform the system shown in FIG. 1;

FIG. 3a shows an enlarged perspective view of a portion of FIG. 3;

FIG. 3bis a perspective view similar to FIG. 3a showing a slightly modified arrangement;

FIG. 3c is a cross-sectional view of a portion of the apparatus. shown in FIG. 3;

FIG. 4 is a perspective explanation of a terminal station of an apparatus contemplated herein;

FIG. 5 is a schematic and block electrical circuit diagram used in connection with the terminal station shown in FIG. 4;

FIG. 6 is a side view of another embodiment of the apparatus contemplated herein;

FIG. 7 shows a variation of the drive arrangement;

FIG. 7a is a side view of still another embodiment of the apparatus contemplated herein using the drive arrangement of FIG. 7;

FIG. 7b is a cross-sectional view of the apparatus shown in FIG. 7a;

FIG. 7c is a perspective illustration of a variation of the concept shown in FIG. 7a;

FIG. 7d presents yet another variation of the concept shown in FIG. 7a;

FIG. 7e is a partly perspective and partially sectional view of an apparatus embodying the concepts depicted in FIGS. to 7d, and FIG. 8 is a similar view of an actual apparatus.

DETAILED DESCRIPTION Broad Outline of the System As hereinbefore pointed out, it is necessary to provide for an automatic and continuous centrifuging operation which will provide each separate sample with the required work period without stopping between operations and furthermore provide a sequential system so that one or many samples may be rapidly and sequentially loaded at one end of the apparatus and unloaded at the other.

Aschematic and block diagram of the system is illustrated in FIG. 1 which shows an apparatus 100 having a revolving line 102 driven by turning means 104 and supported by a driven element 106. The revolving line 102 is designed to hold a sample container 108. The sample container is rotatable and has affixed thereto a rotator 110. This sample container will be mounted on the rotating line 102 and carried along a path of travel having one or more work stations. One of these work stations will be the centrifuging field and will have rotator turning means 112 which will cause the rotator 110 to turn so as to centrifuge any liquid in the container. After the centrifuge station there will be a sample container unloading-station 114 where the sample containers are unloaded and carried to other work stations.

The Containers FIG. 2a'is the design of a collecting sample container useful for the purposes of the present invention. FIG. 2a shows a top-shaped round container with a central disc-shaped section 17' which may be called the side chamber. It will be seen that a neck 19 is provided which can be stoppered so that the container can be evacuated. By using a double needle, one inserted in the vein of a patient and the other through a rubber stopper blood will be aspirated into the container. These containers substitute for and are used in lieu of test tubes with the ability to act as vacuum containers.

As an alternative, the blood from the patient can be placed directly in the container from a syringe and it can be stoppered.

The containers 15 can be described as top-shaped with a flanged neck 19, a barrel-shaped center 21, a side chamber defined by a central disc 17 a narrowing bottom 23 a cylindrical item section 25 to hold the container with inner bottom depressions 27 to serve as holding or spinning means.

The container shown in FIG. 2a and 2b is designed to hold 5 ml of blood. These can be made in any size. They may or may not contain an anticoagulant.

If the container shown in FIG. 2a is spun around its vertical axis, the blood is driven laterally by centrifugal forces taking the position shown in FIG. 2g. When spinning stops the serum or plasma will slide down taking the position shown in FIG. 2h. The heavier cells with or without the clot will be driven into the side chamber, i.e.,;disc like section. The disc portion has a narrow orifice of the order of 2-3 mm. By means of its design it can be made to hold a volume somewhat larger than the volume of the erythrocytes.

The volume ofa cylinder is given by 1r rh. If one subtracts the volume of the inner cylindrical ring from the outer cylindrical disc one obtains the volume held by the disc. If h is the height of the disc, R the total disc radius and r the radius of the inner ring, this volume would be 11' R): 1r r h, or 1r h (R r In FIG. 2b and 2a the volume held in the side container would be 3 ml for a 0.3 mm height and a 1.5 cm distance shown. This means that 3ml of the blood would be in this chamber and the remainder outside. When the rotation stops the serum or plasma will slide to the bottom of the container leaving the cells with a small amount of serum or plasma in the side chamber and cell free serum or plasma at the bottom of the container. This is so because of the well known phenomenon that if water is placed in a tube sealed at one end, and with a narrow orifice, then inverting the tube will cause no liquid to flow out because it is held in by air pressure. This principle is used in perfume bottles and hair tonic bottles. One must shake vigorously to obtain some flow out of the bottle.

The design of the container can take the form of FIG. 2c showing a container 15a with the side chamber having knob-like wings 17a in which case a large volume can collect in the side chamber without making the container orifice unduly wide.

Other shapes are also possible and one is shown in FIG. 2d showing a container 15b with large wings 17b. It is also advantageous to use the configuration shown in FIG. 20 and 2f with inclined wings 17c. The container with the configuration shown in, FIGS. 2e and 2f have the advantage that a narrow orifice to the side chamber is unnecessary. When the container stops spinning, the erythrocytes will remain in the side chamber held by gravity. This is particularly useful where larger volumes are used.

When spinning, the device shown in FIG. 2a will drive the cells 29 into the outer disc (FIG. 2g). The cell free serum or plasma 31 will then fall free when the spinning stops leaving the cell behind in the disc (FIG. 2h).

In subsequent operations, where a protein precipitant is added to the serum, the precipitate has strong coherence. In this case, a design such as FIG. 2d can be used. If spun at 12,000 r.p.m. this precipitate will collect in the corners of wings 17b and pack. On stopping the rotation the centrifugate will drop to the bottom, the precipitate adhering to the corners.

The type of container shown in FIGS. 2a to 2h has an additional advantage. If these containers are used in I subsequent sampling there is no danger of picking up the cells in the pipette since they are locked in the side chamber. This is a serious problem in sampling from test tubes. Further, when returning serum to the test tubes the cells are stirred up and the tube needs to be recentrifuged. This is avoided in the container of FIGS. 2a, 2c and 2e. The advantages of such containers may then be summarized as follows:

1. The tube may be spun to separate the cells from clotted or unclotted blood.

The cells are separated into a separate compartment.

3. The serum or plasma is isolated from the cells and components are therefore more stable.

Sampling from the container is done without fear of cell contamination.

5. Serum or plasma may be' returned to the container without stirring up the cells.

In effect, the container becomes a serum or plasma separator. Since blood contains, usually from 35 47 percent of erythrocytes, by removing percent one is assured of removal of all the cells. From 5 ml, 2 ml of clear serum or plasma is thusobtained. This is approximately what is obtained with conventional techniques.

The containers of FIGS. 2a 2h then permit the design of a continuous centrifuge system. One form of this invention can be seen in FIG. 3. The objective is to rotate the cups in a sequential fashion. Each cup needs to be rotated for at least 5 minutes. If it is desired to have them delivered at the rate of one every 30 seconds and spin each for 5 minutes, then 10 cups must be spinning at the same time.

In some cases, it is not necessary to remove the serum from the clot, after centrifugation. In this case, a simpler design can be used for the cup. This takes the form of a small Erlenmeyer flask in which the bottom has been pushed up so as to create a side chamber, disposed laterally at the bottom of the container as shown in FIG. 2. In this case, after centrifugation the clot moves into the side cham bers'leaving the serum above it. one such cup 815 is shown in FIG. 8.

The cups shown in FIGS. 2a-2h show the side chambers to be at different angles. The rate of settling will be affected by the angle the walls make with the horizontal. As the cups rotate on their central axis the solid particles move outward and if the wall is vertical, would reach the wall and stay there. There would be no downward component of the force. When the wall is at an angle, the reaction of the wall on the particle tends to drive it back in a motion perpendicular to the wall. This motion may be divided into a horizontal or remixing component and a downward component. If the wall is at 45 to the base then both components are equal. If the angle is substantially greater than 60 the downward component is small and a long time will be needed for settling. In order to achieve a compromise between excessive width to the container and minimal mixing on decelerating, an angle of approximately 57 is suitable for practicable purposes.

The Processing Apparatus Friction Drive In FIG. 3 is shown an apparatus 33 for rotating the containers 15. The drive apparatus 33 has a large sprocket 35, driven by a small sprocket 37, by means of a chain 39. Mounted on the chain 39 are a plurality of C-shaped brackets 41 as shown in FIG. 3a or box-like brackets as shown in FIG. 3b, having upper and lower ball bearing apertures 43, 45 holding therein a flexible rod 47 disposed normal to the chain, i.e., the chain moves horizontally and the rods are disposed vertically at the bottom of each rod is an outwardly tapered rotor 49 while at the top is an open trunnion cup 51. The chain 39 is engaged by the sprockets 35, 37 and rotates slowly in the horizontal plane driven by motor 65. At

the sample loading station 53 the containers e.g., those shown in FIGS. 2 h are loaded on the trunnion cups.

Motor 65 rotates slowly. This turns the sprocket 37 which turns the larger sprocket 35. The large sprocket 35 is pinned on an axle 36. This motion serves to bring the assembly of the container 15, the trunnion cup 51, its shaft 47 and a small rotor 49 around the large sprocket 35. As this assembly approaches the sprocket, the small rotor 49 engages the friction disc 63- which is moving at high speed driven by motor 57. Since, as it approaches, it gradually makes contact with this disc, the rotors 49 engage slowly, and are accelerated until they reach top speed as they move around the friction disc 63. This rotation will continue during the travel of the container 15 around the large sprocket 35. After the cups leave the spinning area, they idle, slowing down gradually. They are then removed to a belt line for further processing such as in a system of the type described.

Thus, the containers 15 are placed in trunnion cup 51, i.e., in holders. Each container has two little recesses 27 on the bottom (FIG. 2b) which fit into two corresponding nipples in the trunnion cup holders. The edges of the trunnion cup are flexible on the end so that when the cup is inserted, it clips over the edge serving to hold it in place. These trunnion cups 51 are mounted on the chain through the bracket 41 and ball bearings 43, 45. The rod 47 supporting the cup is somewhat flexible so as to take advantage of the self-balancing principle well known to operators of high speed centrifuges or even laundry centrifuges. At the bottom of the rod is the rotor 49 which is rubber edged. This edge is bevelled in such a way so that lifting of the centrifuge motor 57 and friction disc attached, will make contact. This permits adjustment so that all small rotors make contact and are still not too tight.

As the friction disc 61 spins, it causes the small rotor 49 to spin under each cup. In one model, the friction disc was seven inches across and the small rotor was one inch across, the ratio of circumferences is approximately 21: 3, or seven to one. This is' an advantage since the centrifugal motor 57 need not spin as rapidly. The higher the speed of centrifuging, the faster will the red cells settle. In one application the friction disc was moved at 2000 r.p.m. causing the small rotor to spin at 14,000 r.p.m. If the friction disc is spun at 1000 r.p.m., then the small rotor moves at 7000 r.p.m. Even at the lower speed the cells are separated in ten minutes. The chain is rotated slowly by a second motor 65. This motor is a slow gear motor moving counter to the rotation of the centrifugal motor. This moves the specimens into and out of the centrifugal field. This gear motors speed is adjustable since the time required for separation of various precipitates is variable and in certain applications more or less time is required.

The chain encompasses 3/5 of the large sprocket. Thus 3/5 X 21 approx. 15 inches is available for the centrifugal operation. Since the center of each specimen is a 3 inch distance from its neighbor, the model could simultaneously spin 5 specimens. If it is desired to have each specimen to be in the centrifugal field for 10 minutes, this means that the large sprocket must move 3/5 of its circumference in ten minutes, or one rotation in 14 minutes. The model with this setting delivers a centrifuged specimen every 2 minutes. The rate of specimen delivery can be increased by increasing the size of the large rotor or decreasing the centrifuging time. The latter is achieved by increasing the speed of the centrifugal motor. Rotors as large as 10 inches across have been found quite practicable. Speeds up to 3600 r.p.m. of the centrifugal rotor are also practicable. The rotors are made preferably of aluminum. A silicon rubber belt encompasses the rotor to provide the necessary friction drive. If the rotors are rubber edged, the friction disc need not be and still maintains adequate friction for spinning.

After the sample has been spun, the sample can be removed by hand. As a table top centrifuge, for a few specimens, the operator adds a few samples and sets the machine to automatic stop. When the last sample exits, the instrument stops and the operator can pick up his specimens.

The engagement between the friction disc 61 and the small rotor used to turn the trunnion cup 51 may perhaps best be understood from FIGS. 3b and 30. In this figure, the motor 57 drives the friction disc 61 having a hard silicone rubber wall 63a. Disposed for rotation above rotor drive disc 61 is a chain 39 held by a large sprocket 35 which engages chain 39. Mounted on the outside of the chain 39 is a bearing unit 41a similar to the one shown in FIG. 3a. This bearing unit 410 holds a flexible shaft or rod 47 having a trunnion cup 51 on top which holds the container 15, and, a small rotor 49a made of metal with a rubber wall 65. The side of the rubber wall 65 is inclined and will dovetail alongside of the adjacent silicone wall 63a.

At the end of the run, a transfer device for removing the sample from the automatic centrifuge and transferring it to a belt line is necessary. A devicevwith some similar elements has already been described in the Samuel Natelson U.S. Pat. No. 3,331,665, and the device required is shown in FIG. 4.

A clamp 67 which resembles in appearance that of a spring clothes pin rotates in a circle. A cam 69 operated by a cam motor 70 rotates to lift and lower a rod 71- having a gear 72 thereon. The rod moves in a thrust bearing 720 which is fixed in place. This gear 72 is engaged by a A inch thick driver gear 74. Gear 72 is 1% inch in thickness so that the rod can be lifted without disengaging from gear 72. Gear 74 is operated by a turn motor 76. The clamp is 3 inches in length from jaw to axis so that it moves in a 6 inch circle. When operated in conjunction with the automatic centrifuge, motor 65 operating the sprocket of the centrifuge stops when clamp is positioned over the sample container, and turn motor 76 also stops. A solenoid 79 with an armature 81 is activated and the clamp 67 is lowered by the cam over'the neck 19 of the container 15. The solenoid is deactivated and the container is clamped. The cam now raises the rod so that the container clears the trunnion cup 51. Motor 65 and turn motor 76 are reactivated and the clamp continues its rotation carrying the container in the a position over a belt line 83 driven by a belt motor 85. When the clamp is positioned over the belt line, the belt line motor 85 stops as well as turn motor 76. The cam lowers the container into a container holder 87. The solenoid is reactivated releasing the container. The cam raises the clamp. Turn motor 76 and belt motor 85 are reactivated and the cycle is repeated.

The positioning of the clamp above the centrifuge holder and belt holder is controlled by two light and photocell assemblies which control two timer switches. The timer arrangement 90 is shown in FIG. 5. Referring to FIG. 5, movement of the clamp of FIG. 4 between light 92 and a photocell 94 closes a photoswitch 96. When photoswitch 96 is closed, relay 98 closes. This activates timer motor 1220 which moves from stop to a pin 122 which has a flag. This delivers current to motor 76, which starts to run. When relay was depressed with switch closed, the motor stopped because a first circuit a was interrupted. The turn motor 76 could not run for the time period that the flag was travelling. When the pin is finally closed (after 8 seconds) by pass is provided through a circuit b which originates behind the photoswitch. The turn motor 76 operating rotating rod 72 starts and moves the clamp around and out of the field of the photoswitch. The photoswitch opens and relay 98 is inactivated reactivating circuit a. Current to the timer motor 122a is interrupted and the flag flips back to flag stop. The cycle is then repeated.

When turn motor 76 is activated a second motor M can be attached in parallel. Thus when turn motor 76 is running so does motor M' when turn motor 76 stops so does motor M. Thus the automatic centrifuge stops when the clamp is positioned over the specimen. A third motor can also be attached to the arrangement so that when the clamp interrupts the second photoswitch positioned above a belt moving the specimens, the movement of the belt stops. This permits the container to be deposited in the cup. In actual practice it is preferable to have two independent systems. One stops and starts the automatic centrifuge. The other starts and stops the belt. In both cases the clamp holding the container stops at each station at the time that station is not moving.

The instrument herein before described operates in the circular mode. A variation of the instrument is an operation in the linear mode. This is shown in FIG. 6 showing a belt 123 driven by gears 125 and in FIG. 7a showing a chain 120 driven by gears. These gears are activated by motor and pulley attachment 121. This chain 120 rotates in the vertical plane, and has a series of bearings 124 holding shafts 126 therein. The outer ends of shafts 126 have trunnion cups 128 to hold a container 15. The lower end ofthe shaft has a rotor member 130 similar to the small rotor 49 of FIG. 3a. Alongside chain 120 is a plastic friction belt 132 rotating in the horizontal plane driven by a motor 134. Belt 120 runs at high speeds spinning the containers 15 supported on trunnion cups. The container is first placed in the cup. It then moves across until the rotor engages the plastic belt 132 which is driven by the centrifugal motor 134. This causes the rotor to spin. As it moves along, it moves out of the centrifugal field. The container slows down and stops spinning. The container is then removed by the device shown in FIGS. 4 and 5. The holder now moves below the belt. The gears 122 are 4 inches in diameter so that as the trunnion cups move below the belt, clearance is allowed for the rotors. In the inverted position, they clear the plastic belt so they are not spun.

In both the circular and horizontal mode contact between the rotor of the trunnion cup and centrifugal rotor or belt is made slowly and gradually so that the cup starts to spin at a lesser speed due to slippage. As it moves on, firmer contact is made. This has the effect of gradually accelerating the containers and avoids splashing.

The Processing Apparatus Gas Drive The containers shown in FIG. 6 may also be spun by compressed air as shown in FIGS. 70, 7b, 7c. The arrangement shown in FIG. 7a is similar to FIG. 6 but the belt 132 and motor 134 are removed. The belt is replaced with a source of compressed air. The rotors are replaced by turbines to spin as the air flows across them. These air driven turbines consist of a housing cage 152 holding a plurality of curved radial vanes 154. The curvature of the vanes will determine the direction of rotation of the shaft 126. At the side of the turbine 150 is an air supply 156 consisting of a rectangular box-like outlet 1S8 fed by air, with a plurality of parallel partitions 160 to guide the air flow. As the turbine approaches the air supply 156 it starts to rotate and continues to rotate well past the air supply 156. The container is removed at the end of the run by the device of FIG. 4 while the trunnion cup 128 and shaft 126 pass under the air supply. The turbine is at the center of the belt and clears the axle connecting the gears driving the belt.

The instrument of FIG. 3 can also be modified to spin the cups by compressed air. In this case, the friction drive 61 and motor 57 (shown in FIG. 3c) are removed and replaced by the arrangement shown in FIG. 7c. The small rotors 47 are replaced with fan blades or turbines 147. A source of compressed air 156a blowsover the turbines while they are in the centrifugal field. In this mode, the trunnion cups are not turned over. The compressed air is released from radial chambers 157a defined in a horizontally disposed drum 157. The centrifugal field may be defined by blocking off some of the chambers by a blank 157b.

As a variation of this design, the drum delivering the compressed air can rotate. This is shown in FIGQ7d. The drum 159 delivering the compressed air is fed by a compressed air supply 15Gb. The drum 159 is mounted on a sleeve l56c which rotates while feeding air out of the drum through nozzles 1590. The centrifugal field is again defined this time by a shoe l59b. In carrying the foregoing concepts into practice, the bmbodiment depicted in FIG. 7e is quite useful. The compressed air supply is fed through a rotating central system into passages 160 which carry the-compressed air to a position under the'turbine where it is blown at the turbine by a vertical passage 162. The travel path of the apparatus is in the horizontal plane'as shown in FIG. 3. The drive is by means ofa chain 239 driven by a sprocket arrangement, part of the arrangement of sprockets 235 being shown in FIG. 7e driving the chain. Held by the chain is a bracket type bearing arrangement 241 holding a turbine 250 at the bottom and a trunnion cup 251 over the bearing arrangement so that the compressed air coming out of vertical passage 162 will'hit the turbine 250 and turn the trunnion cup 251. Mounted in the trunnion cup 251 is a centrifugal cup lock 253. The container 15 is placed in the trunnion cup 251 and as long as it is not spinning, the cup lock 253 will not latch on to the container 15. However, the cup lock 253 is formed of an engaging portion and a heavy tail and is pivoted towards the engaging portion. As the trunnion cup. starts to spin, the heavy tail will tend to fly outwardly pushing the engaging portion against the container 15 held in the trunnion cup. The engaging portion will engage a flange or indentation and hold the container tight. When the spinning stops the engaging portion will release and allow the container to be removed.

The automated centrifuge may also be used as an automated micro hematocrit centrifuge. In this case, capillaries containing blood are disposed in recesses on a plate supported on spinners. Rotation drives the red cells to the bottom of the capillaries and the hematocrit may then be measured when the carriers emerge from the centrifuge. Another application is a micro centrifuge. In this case a plate with holes angularly bored on the plate spins on the rotors. Small plastic test tubes with lips having a capacity of about 0.1 to l milliliter are inserted into these holes. A precipitate contained in the micro test tubes is driven to the bottom as the spinners pass through the automated centrifuge.

A variation of the instrument shown in FIG. 8 which eliminates the use of a chain uses a metal disc 802. The supports for the trunnion cup 804, shaft 806, and fan assembly 808, are mounted at the periphery of this metal disc 802. The metal disc 802 is rotated slowly by means of a gearmotor or belt drive assembly from below or above the disc. Compressed air from an air inlet 810 and air passages 811 blows across the fans during their travel over 3/5 of the circumference of the disc. The trunnion cups 804 and containers 815 contained therein rotate at high speed as they pass the compressed air area. They then slow down, their rotation being damped by the spinning blades in air, and come to rest when they move out of the air jet flow area. In this mode the trunnion cup assembly moves in a circle.

The turbine and jet assembly is also practical in this arrangement. The jets come from a series of pipes radially disposed from the central disc which rotates and moves along with the fans maintaining their relative position. When these turbine assemblies have moved through 3/5 of the circle, the air jet flow in the pipe activating them is interrupted so that the rotation ceases and the cups can be removed. The containers are held by a centrifugal lock 817 having an inwardly biased spring 819 and a locking piece 820. The extent of centrifugal work field may be defined by an air cut off shoe 822.

What is claimed is:

1. A process for the sequential centrifugation of liquid chemical samples comprising the steps of depositing the samples in a series of containers each having a peripheral side chamber, causing each of said containers to spin sequentially on its own substantially vertical axis for a predetermined time period so as to separate at least one component of the samples into said chambers and decelerating the rotation gradually until said containers come to rest without remixing of the components.

2. An apparatus for the sequential centrifugal treat ment of liquid samples, comprising in combination:

a. a movable carrier having bearing means mounted thereon, said carrier having a travel path;

b. at least one vertical shaft rotatably mounted on said bearing means, said shaft having a shaft rotator at the lower end thereof and a trunnion cup at the upper end thereof; and,

c. a work station, rotation means at said work station along said travel path to rotate said shaft rotator as dwells in said work station.

3. An automated centrifuge arrangement for use in an automated system of analysis comprising in combination a plurality of holders to hold containers, said holders including a central bearing, a cup shaped container receiving section over said bearing and a rotating portion below said bearing,-means for supporting said holders; and,

a work station including rotation means for rotating said holders about the central axis of said container receiving section, and means for decelerating and bringing said holders gradually to rest.

4. An arrangement as claimed in claim 3 including two opposed vertically turning wheels, said travel means comprising an endless travel line traveling between said two opposed vertically turning wheels at least one of which is the driver wheel.

5. An arrangement as claimed in claim 3, including a turbine, said rotation means being an air jet directed at said turbine said air jet moving along with said turbine maintaining its relative position to said turbine for a preset distance, said air jet then being interrupted to allow said holder to come to rest,

6. An arrangement as claimed in claim 3, including travel means for bringing and removing said holders to and from said work station.

7. An arrangement as claimed in claim 6 wherein said travel means comprises an endless travel line turning in the horizontal plane.

8. An arrangement as claimed in claim 7 wherein said travel means includes a driven and a driver sprocket and said travel line comprises a chain.

9. An arrangement as claimed in claim 7 wherein said holders rotating portion comprises an outwardly tapered roller and said rotating means comprises a rotating disc, said roller being gradually engaged by said disc as it enters the field, said rollers rotational speed increasing as the engagement by said disc continues and gradually decreasing as said roller leaves said field. I

10. An arrangement as claimed in claim 6, said holders including a vertically disposed shaft disposed in said central bearing with upper and lowershaft portions, said cup-shaped container receiving section being mounted on said upper portion and said rotating portion being mounted on said lower portion responsive to said rotating means.

11. An arrangement as claimed in claim 6 wherein said holders rotating portion comprises a roller and said rotating means comprises a rotating disc, said roller being gradually engaged by said disc as it enters the field said roller's rotational speed increasing as the engagement by said disc continues and gradually decreasing as said roller leaves said field.

12. An arrangement as claimed in claim 6 wherein said holders rotating portion comprises a blade means and said rotating means comprises gas jet means disposed for directing an air jet at said blade means, said blade means gradually turning as said gas jet means hits the blade means entering the field, increasing through the field and decreasing as the blade means leave the field.

13. An arrangement as claimed in claim 6, wherein said travel means comprises a circular .disc which rotates on its axis.

14. An arrangement as claimed in claim 6, including means for'bringing and removing said containers to and from said holders.

15. An apparatus for the sequential centrifugal treatment of liquid samples comprising in combination.

a. travel means moving along a horizontal path of travel ast a work station b. a cen rifuging field worlt station including a plurality of gas feed lines each terminating in a jet section;

c. at least one holder mounted on said travel means including a central bearing connected to said travel means; lower blade means which will rotate as said holder enters said field because of the jet of gas thereon and an upper cup-like section having a pivoted clip therein, said clip having an engaging upper section and a weighted lower section, said lower section flying outwards upon the rotation of said holder to cause said engaging upper section to engage and hold a container in said holder.

16. An apparatus as claimed in ciaim 15 said gas feed lines being defined in rotating radial lines.

17. A process for the separation of a multiplicity of samples of a two phase system, where the two phases are of different density, at least one of the phases being a liquid which comprises the steps of depositing the samples in a series of containers each having a peripheral side chamber, mounting said containers on a carrier, moving said containers continuously past a centrifuging zone, rotating the containers around their central substantially vertical axes to separate at least one component and removing the containers from the carriers at a terminal zone.

18. The process of claim 17 being performed in an automated system of chemical analysis, where samples of the supernatant are removed after separation of phases for further processing.

UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent No. ,7 0 D t d March 27, 1973 Inventofls) SAMUEL NATELSON It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 12, lines 57-59, should read as follows:

-- c. a work station, rotation means at said work station along said travel path to rotate said shaft ro'tator as it dwells in said work station Signed and sealed this 20th day of November 1973.

(SEAL) Attest:

EDWARD M.FLE'ICHER,JR. I RENE D. 1'IEG'IMEYER Attesting Officer Acting Commissioner of Patents FORM PC3-1050 USCOMMDC 60376-P69 I O U.S GdVERNMENT PRINTING OFFICE Z 969 0-356-334,

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U.S. Classification494/11, 118/52, 422/918, 198/377.1, 494/47, 494/24, 494/31, 494/84, 494/37, 422/561
International ClassificationG01N35/02, G01N35/10, B04B5/04, G01N35/00, B01L3/14, G01N35/04, G01N15/04
Cooperative ClassificationG01N2035/00495, G01N35/1004, G01N15/042, G01N2035/0465, B04B2011/046, G01N35/02, B01L3/5021, G01N35/021, G01N35/1083, B04B5/0407
European ClassificationB01L3/5021, B04B5/04B, G01N15/04B, G01N35/02B, G01N35/02