ANALYZER HAVING A ROTATABLE SAMPLE RACK CARRIER

Abstract: An automatic chemical analytical apparatus for analyzing liquid samples. In order to provide a fully automatic transport of sample tubes containing samples to be analyzed the apparatus comprises a sample processing unit (61), sample transport means for transporting the sample racks (16) from a rack supply unit (18) to a rotatable sample rack carrier (19) in the sample processing unit and vice versa, and means for controlling and coordinating the operation of the sample transport means and the automatic pipetting unit (11). Sample processing unit (61) comprises an automatic pipetting unit (11) and a rotatable sample rack carrier (19) adapted to accommodate a plurality of sample racks (16), each sample rack (16) being adapted to accommodate a plurality of sample tubes (12).

Description: Analyzer having a rotatable sample rack carrier The invention concerns an automatic chemical analytical apparatus for analyzing liquid samples. The invention concerns in particular an automatic chemical analytical apparatus comprising - an automatic pipetting unit for aspirating a sample portion from a selected sample tube that forms part of an array of sample tubes located in a sample tube area , and for delivering said aspirated sample portion to a selected reaction tube that forms part of an array of reaction tubes located in a reaction tube area, each sample tube carrying on it an identification readable by a reader device, - a plurality of elongated sample racks each of which has a length axis and is adapted to accommodate a plurality of sample tubes each sample tube being filled with a sample, each sample rack carrying on it an identification readable by a reader device, - a rotatable sample rack carrier located in said sample tube area , said rotatable sample rack carrier being adapted to accommodate a plurality of said sample racks within a space delimited by a circumference , said sample racks being arranged along said circumference with the length axis of each of said sample racks substantially orthogonal to said circumference. An analytical apparatus of this kind is described in European Patent specification No. EP 0325101 Bl. This document contains no description of any means for automatically transporting sample racks from a rack supply unit to the rotatable sample rack carrier and for positioning the sample racks on that rack carrier or for automatically removing the sample racks from that carrier and transporting them back to the rack supply unit. Therefore, according to EP 0325101 Bl the latter transport and positioning and removing operations have to be done manually. In order to improve the reliability of the operation of such an analytical apparatus and more in general in order to improve the overall performance of such apparatus it is desirable to avoid as far as possible any manual operations for the transport of the sample tubes. The aim of the invention is therefore to provide an analyzer of the above mentioned kind wherein the transport of the sample tubes is completely automated. According to the invention this aim is achieved with an automatic analytical apparatus of the above mentioned kind which comprises: (a) an automatic pipetting unit for aspirating a sample portion from a selected sample tube that forms part of an array of sample tubes located in a sample tube area , and for delivering said aspirated sample portion to a selected reaction tube that forms part of an array of reaction tubes located in a reaction tube area , each sample tube carrying on it an identification readable by a reader device, said automatic pipetting unit comprising a pipetting needle and means for moving said needle in 3 directions which are orthogonal to each other, (b) a plurality of elongated sample racks each of which has a length axis and is adapted to accommodate a plurality of sample tubes each sample tube being filled with a sample, each sample rack carrying on it an identification readable by a reader device, (c) a rotatable sample rack carrier located in said sample tube area , said rotatable sample rack carrier being adapted to accommodate a plurality of said sample racks within a space delimited by a circumference , said sample racks being arranged along said circumference with the length axis of each of said sample racks substantially orthogonal to said circumference , (d) sample transport means for transporting said sample racks from a rack input device of a rack supply unit to said rotatable sample rack carrier , and for selectively transporting said sample racks from said rotatable sample rack carrier to a rack output device of said rack supply unit , said rack input device and said rack output device being each adapted to accommodate a plurality of said sample racks , said sample transport means including means for effecting a step-wise rotation of said rotatable sample rack carrier , said step-wise rotation comprising rotation intervals and rotation stop intervals, during which said sample rack carrier is at rest, (e) said automatic pipetting unit being adapted to aspirate a portion of a sample contained in a selected sample tube located in a selected sample rack carried by said sample rack carrier at a point of time within a time interval during which said rotatable sample rack carrier is at rest, and for delivering said aspirated sample portion to a selected reaction tube in said reaction tube area , and (f) means for controlling and coordinating the operation of said sample transport means and said automatic pipetting unit. The main advantage of an analytical apparatus according to the invention is that it includes means which provide a completely automatic transport of the sample tubes, and that these means makes possible to attain simultaneously two aims: - on the one hand to provide such automatic transport at a relatively low cost and with a simple structure which facilitates service work and thereby reduces service expenses, and - on the other hand to coordinate such automatic transport of sample tubes with the necessary sample pipetting operations, and to enable selective random-access to any of the sample tubes in the sample area for carrying out those pipetting operations. Achievement of these aims contributes to optimize/increase the number of samples the analytical apparatus is able to analyze per unit of time. Moreover, since according to the invention the sample racks remain on the rotatable sample rack carrier as long as analysis of any of the sample tubes contained therein is not yet completed, the sample rack carrier serves also as buffer for sample racks, and in this way the instant invention eliminates the need for a separate sample rack buffer. Preferred embodiments of the invention are described hereinafter more in detail with reference to the accompanying drawings . Fig. 1 shows a schematic partial top view of an analyzer system according to the invention. Fig. 2 shows a schematic side view of one of the racks 16 shown by Fig. 1 and of sample tubes 12 contained therein. Fig. 3 shows a schematic cross-sectional view of mechanical means for moving a sample rack 16 along transfer line 23 shown by Fig. 1. Fig. 4 shows a schematic cross-sectional view of the mechanical means shown in Fig. 3 in a plane perpendicular to the plane of the cross-section represented in Fig. 3. As shown by Fig. 1 an embodiment of an automatic chemical analytical apparatus according to the invention comprises: a) a sample processing unit 61 comprising: - an automatic pipetting unit 11, and - a rotatable sample rack carrier 19, adapted to accommodate a plurality of said sample racks 16, each sample rack 16 being adapted to accommodate a plurality of sample tubes 12, b) sample transport means for transporting sample racks 16 from a rack supply unit 18 to rotatable sample rack carrier 19, and for selectively transporting sample racks 16 from rotatable sample rack carrier 19 to rack supply unit 18, and c) means for controlling and coordinating the operation of the sample transport means and automatic pipetting unit 11. Rack supply unit 18 comprises a rack input device 17 and a rack output device 21. In a preferred embodiment rack supply unit 18 is located outside sample tube area 13 and comprises a stationary rack input device 17 and a stationary rack output device 21. In a preferred embodiment rack supply unit 18 is a separate module which is adapted to cooperate with sample processing unit 61 as described hereinafter, but which is not a part of the latter unit. For this purpose rack supply unit 18 is so configured that sample racks 16 located in are accessible for transport to and from sample processing unit 61. A preferred embodiment of automatic pipetting unit 11 comprises a pipetting needle and transport means for moving the pipetting needle in 3 directions X, Y, Z which are orthogonal to each other. Such an transport system of the pipetting needle enables a random-access to samples contained in sample tubes carried by rotatable sample rack carrier 19. In a preferred embodiment sample processing unit 61 comprises a sample tube area for receiving sample tubes to be analyzed and a reaction tube area for receiving reaction tubes where the necessary reactions of the samples with suitable reagents take place. In a preferred embodiment the sample tube area 13 includes space reserved for accommodating one or more additional sample tube racks which are manually positioned on a stationary support, that is sample tube racks which are not transported by the sample transport means of an analytical apparatus according to the invention. Automatic pipetting unit 11 is adapted for performing pipetting operations such as e.g. aspirating a sample portion from a selected sample tube 12 that forms part of an array of sample tubes 12 located in a sample tube area 13, and for delivering the aspirated sample portion to a selected reaction tube 14 that forms part of an array of reaction tubes 14 located in a reaction tube area 15. Automatic pipetting unit 11 is controlled by suitable control means in order to perform such pipetting operations successively with respect to a plurality of sample tubes, respectively reaction tubes. Each sample tube 12 carries on it an identification readable by a reader device 27. Rotatable sample rack carrier 19 is located in sample tube area 13 and is adapted to accommodate a plurality of sample racks 16 within a space delimited by a circumference 22. Sample racks 16 are arranged along circumference 22 with the length axis of each of sample racks 16 substantially orthogonal to circumference 22, that is, the length axis of each of the sample racks 16 is radially oriented with respect to the axis of rotation of rotatable sample rack carrier 19. As can be appreciated from Figures 1 and 2 each sample rack has an elongated shape and a length axis and is adapted to accommodate a plurality of sample tubes 12 containing each a sample to be analyzed. As shown by Fig. 2 sample tubes 12 can have different sizes, e.g. 4 ml or 7 ml as indicated for some of the sample tubes shown by Fig. 2. On the right side of Fig. 2 lengths in millimeters are indicated. Each sample rack 16 carries on it an identification readable by a reader device 27. In a preferred embodiment sample tubes 12 are arranged substantially in a row along the length axis of sample rack 16. The sample transport means is adapted for transporting sample racks 16 from a rack input device 17 of rack supply unit 18 to rotatable sample rack carrier 19, and for selectively transporting sample racks 16 from rotatable sample rack carrier 19 to a rack output device 21 of rack supply unit 18. Rack input device 17 and rack output device 21 are each adapted to accommodate a plurality of sample racks 16. The sample transport means includes means for effecting a step-wise rotation of rotatable sample rack carrier 19. This step-wise rotation comprises rotation intervals and rotation stop intervals, during which sample rack carrier 19 is at rest . In a preferred embodiment the sample transport means are adapted for transporting sample racks 16 one-by-one from rack input device 17 to rotatable sample rack carrier 19. In a further preferred embodiment the sample transport means are adapted for selectively transporting sample racks 16 one-by-one from rotatable sample rack carrier 19 to rack output device 21. A typical pipetting operation effected by automatic pipetting unit 11 is e.g. aspiration of a portion of a sample contained m a selected sample tube 12 located m a selected sample rack 16 carried by sample rack carrier 19 at a point of time withm a time interval during which rotatable sample rack carrier 19 is at rest, and delivery of the aspirated sample portion to a selected reaction tube 14 m reaction tube area 15. The control means which control and coordinate the operation of the sample transport means and the automatic pipetting unit 11 include e.g. a computer which receives all necessary information from the different parts which constitute the analytical apparatus, which generates corresponding command signals for controlling automatic pipetting unit 11 and various parts of the sample transport means according to a suitable program which provides an optimized operation of the system components which participate to the transport of the sample racks 16 for a predetermined range of number of samples processed by the system by time unit. In a preferred embodiment the sample transport means include - a transfer line 23 for effecting the transport of sample racks from rack supply unit 18 to rotatable sample rack carrier 19 and vice versa, - means for moving serially and one-by-one sample racks 16 from rack input device 17 to transfer line 23, - means for moving one-by-one sample racks 16 from transfer line 23 to rack output device 21, - means for moving one-by-one sample racks 16 from transfer line 23 to rotatable sample rack carrier 19 and vice versa, - means for effecting a step-wise rotation of rotatable sample rack carrier 19, and - a reader device 27 for reading the identification of each sample rack 16 and the identification of each sample tube 16 contained therein during their transport from the rack supply unit 18 to the rotatable sample rack carrier 19. In a preferred embodiment the sample transport means further comprise means for moving a sample rack 25 containing at least one sample that requires urgent analysis from a rack input position 26 for such kind of rack to transfer line 23 in order that such sample rack 25 can be transferred to rotatable sample rack carrier 19 with high priority. In a preferred embodiment transfer line 23 is a single transfer line 23 for transporting sample racks 16 in two opposite directions, that is, from rack supply unit 18 to rotatable sample rack carrier 19 and vice versa. Figures 3 and 4 show schematic cross-sectional views of mechanical components which form part of an embodiment of transfer line 23 described herein as example. These components cooperate with each other for moving a sample rack 16 along transfer line 23 shown by Fig. 1. As can be appreciated from Figures 3 and 4, a sample rack 16 is displaced on a support plate 49. Transport of sample rack 16 in a desired direction is achieved by means of a carriage 41 and a transport chain 45. Carriage 41 is removably connected to sample rack 16 by means of a pin 42. The upper part of a pin 42 of carriage 41 is removably lodged in a corresponding cavity of the bottom wall of sample rack 16. As shown by Fig. 7, guiding rolls 43 and a guiding rail 44 guide movement of carriage 41. A chain guide 46 guides movement of chain 45. A base plate 48 supports guiding rail 44 and mechanical components which cooperate with it. As shown by Fig. 6, a carrier bolt 51 connects carriage 41 to chain 45. Pin 42 is fixed to carriage 41 by means of a set screw 53. Carrier bolt 51 is fixed to carriage 41 by means of a set screw 52. The means for effecting a step-wise rotation of rotatable sample rack carrier 19 include e.g. a D.C. motor and a encoder. This D.C. motor is controlled by the above- mentioned control means. The means for effecting a step-wise rotation of rotatable sample rack carrier 19 operate in such a way that the step- wise rotation of rack carrier 19 comprises rotation intervals and rotation stop intervals, during which sample rack carrier 19 is at rest. The step-wise rotation of rack carrier 19 is effected so that at the end of each rotation step a selected one of the sample racks 16 is aligned with and is ready to be transferred to transfer line 23 for its transport to rack output device 21 of rack supply unit 18, or a free position 24 available to receive a sample rack 16 on sample rack carrier 19 is aligned with transfer line 23 for receiving a sample rack 16 arriving to sample rack carrier 19 via transfer line 23. For this purpose the length axis of the end part of transfer line 23 is preferably radially oriented with respect to the axis of rotation of rotatable sample carrier 19. Each rotation step includes rotation of sample rack carrier 19 of an angle determined by the control means, e.g. an angle smaller than 180 degrees. The means for rotating rack carrier 19 are so configured that carrier 19 can be rotated in any of two opposite senses, i.e. in clock-wise sense or in a sense opposite thereto. The means for moving one-by-one sample racks 16 from transfer line 23 to rotatable sample rack carrier 19 and vice versa include means which serve for moving a selected sample rack 16 arriving via transfer line 23 to a free position 24 on sample rack carrier 19, during one of the rotation stop intervals, and for moving a selected sample rack 16 from its position on the sample rack carrier 19 to the transfer line 23, during another one of the rotation stop intervals. The selection of a sample rack 16 to be removed from rack carrier 19 is taken by the control means on the basis of the information available on the status of the analysis operations with respect to every sample tube on carrier 19. Every sample rack 16 remains on rack carrier 19 as long as analysis of a sample tube in that rack has not yet been completed or has to be repeated, because validity of results is deemed to be doubtful. Rack carrier 19 performs therefore also the function of a buffer. A separate sample rack buffer is therefore not necessary. When the analysis of all sample tubes in a sample rack 16 is completed, the control means select that rack and provide the necessary commands in order to remove that rack from rack carrier 19 as fast as possible. Therefore, every sample rack 16 remains on rack carrier 19 only during the minimum time interval required for enabling analysis of the samples on that rack. The identifications carried by the sample tubes 12 and the sample racks 16 are e.g. bar-code labels readable by a barcode reader 27. In the embodiment shown by Fig, 1 bar-code reader 27 is fixedly disposed in the analyzer and is used to read the bar-code labels of each sample rack and of each sample tube contained on each vessel holder as these components pass before the bar-code reader and cross the reading path thereof during their transport on transfer line 23 from rack input device 17 to sample rack carrier 19. List of reference numbers 11 automatic pipetting unit 12 sample tube 13 sample tube area 14 reaction tube 15 reaction tube area 16 sample rack 17 rack input device 18 rack supply unit 19 rotatable sample rack carrier 21 rack output device 22 circumference 23 transfer line 24 free position 25 sample rack (for urgent analysis] 26 rack input position 41 carriage 42 pin 43 guiding roll 44 guiding rail 45 chain 46 chain guide 47 48 base plate 49 support plate 51 carrier bolt 52 set screw 53 set screw 61 sample processing unit Numerous modifications and alternative embodiments of an analytical apparatus according to the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Details of the apparatus may be varied substantially without departing from the spirit of the invention and the exclusive use of all modifications which come within the scope of the appended claims is reserved. -

Claims: Claims 1. An automatic chemical analytical apparatus for analyzing liquid samples comprising (a) an automatic pipetting unit (11) for aspirating a sample portion from a selected sample tube (12) that forms part of an array of sample tubes (12) located in a sample tube area (13) , and for delivering said aspirated sample portion to a selected reaction tube (14) that forms part of an array of reaction tubes (14) located in a reaction tube area (15), each sample tube (12) carrying on it an identification readable by a reader device (27), said automatic pipetting unit (11) comprising a pipetting needle and means for moving said needle in 3 directions (X, Y, Z) which are orthogonal to each other, (b) a plurality of elongated sample racks (16) each of which has a length axis and is adapted to accommodate a plurality of sample tubes (12) each sample tube (12) being filled with a sample, each sample rack (16) carrying on it an identification readable by a reader device (27), (c) a rotatable sample rack carrier (19) located in said sample tube area (13) , said rotatable sample rack carrier (19) being adapted to accommodate a plurality of said sample racks (16) within a space delimited by a circumference (22), said sample racks (16) being arranged along said circumference (22) with the length axis of each of said sample racks (16) substantially orthogonal to said circumference (22), (d) a sample transport means for transporting said sample racks (16) from a rack input device (17) of a rack supply unit (18) to said rotatable sample rack carrier (19), and for selectively transporting said sample racks (16) from said rotatable sample rack carrier (19) to a rack output device (21) of said rack supply unit (18), said rack input device (17) and said rack output device (21) being each adapted to accommodate a plurality of said sample racks (16), said sample transport means including means for effecting a step-wise rotation of said rotatable sample rack carrier (19), said step-wise rotation comprising rotation intervals and rotation stop intervals, during which said sample rack carrier (19) is at rest, (e) said automatic pipetting unit (11) being adapted to aspirate a portion of a sample contained in a selected sample tube (12) located in a selected sample rack (16) carried by said sample rack carrier (19) at a point of time within a time interval during which said rotatable sample rack carrier (19) is at rest, and for delivering said aspirated sample portion to a selected reaction tube (14) in said reaction tube area (15), and (f) means for controlling and coordinating the operation of said sample transport means and said automatic pipetting unit (11) . 2. An apparatus according to claim 1, wherein said sample transport means are adapted for transporting said sample racks (16) one-by-one from said rack input device (17) to said rotatable sample rack carrier (19. 3. An apparatus according to claim 1, wherein said sample transport means are adapted for selectively transporting said sample racks (16) one-by-one from said rotatable sample rack carrier (19) to said rack output device (21. 4. An apparatus according to claim 1, wherein said rack supply unit (18) is a separate module which is not part of said sample processing unit (61) and which comprises a stationary rack input device (17) and a stationary rack output device (21. 5. An apparatus according to claim 1, wherein said sample transport means comprises (i) a transfer line (23) for effecting said sample rack transport from the rack supply unit (18) to said rotatable sample rack carrier (19) and vice versa, (ii) means for moving serially and one-by-one sample racks (16) from said rack input device (17) to said transfer line (23), (iii) means for effecting a step-wise rotation of said rotatable sample rack carrier (19), said step-wise rotation comprising rotation intervals and rotation stop intervals, during which said sample rack carrier (19) is at rest, said step-wise rotation being effected so that at the end of each rotation step a selected one of the sample racks (16) is aligned with and is ready to be transferred to said transfer line (23) for its transport to said rack output device (21) of said rack supply unit (18), or a free position (24) available to receive a sample rack (16) on said sample rack carrier (19) is aligned with said transfer line (23) for receiving a sample rack (16) arriving to said sample rack carrier (19) via said transfer line (23) , (iv) means which serve for moving a selected sample rack (16) arriving via said transfer line (23) to a free position (24) on said sample rack carrier (19) , during one of said rotation stop intervals, and for moving a selected sample rack (16) from its position on the sample rack carrier (19) to the transfer line (23) , during another one of said rotation stop intervals, (v) means for moving one-by-one sample racks (16) from said transfer line (23) to said rack output device (21), and (vi) a reader device (27) for reading the identification of each sample rack (16) and the identification of each sample tube (12) contained therein during their transport from the rack supply unit (18) to the rotatable sample rack carrier (19. 6. An apparatus according to claim 5, wherein said transfer line (23) is a single transfer line (23) for transporting said sample racks (16) in two opposite directions, that is, from said rack supply unit (18) to said rotatable sample rack carrier (19) and vice versa. 7. An apparatus according to claim 5, wherein said sample transport means further comprises means for moving a sample rack (25) containing at least one sample that requires urgent analysis from a rack input position (26) for such kind of rack to said transfer line (23) in order that such sample rack (25) can be transferred to the rotatable sample rack carrier (19) with high priority. 8. An apparatus according to claim 1, wherein said sample tubes (12) are arranged substantially in a row along the length axis of the sample rack (16. 9. An apparatus according to claim 1, wherein said sample tube area (13) includes space reserved for accommodating one or more sample tube racks manually positioned on a stationary support.

Inventors: ROSENBERG BURKARD, SCHACHER GOTTLIEB, ROSENBERG, BURKARD, SCHACHER, GOTTLIEB
Applicants: HOFFMANN LA ROCHE, ROSENBERG BURKARD, SCHACHER GOTTLIEB, F. HOFFMANN-LA ROCHE AG, ROSENBERG, BURKARD, SCHACHER, GOTTLIEB
Application year: 2000
Main classification: G01N35
IPC codes: G01N35