Chemical analyzer

• US 5,250,262 A
• Filed: 12/06/1991
• Issued: 10/05/1993
• Est. Priority Date: 11/22/1989
• Status: Expired due to Fees

• Current Assignee: IDEXX Laboratories Incorporated
• Original Assignee: Vettest SA
• Inventors: Clampitt, Roger, Heidt, Thomas, Will, Henry, Rhodes, Greydon, Plasensia, Armand
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/806,071
• Time in Patent Office: 669 Days
• Field of Search: 422/63, 422/64, 422/82.05, 436/46, 436/54
• US Class Current: 422/64
• CPC Class Codes: G01N 2035/00049 for loading/unloading a carousel
• CPC Class Codes: G01N 2035/00079 Evaporation covers for slides
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 2035/00376 Conductive heating, e.g. heated plates
• CPC Class Codes: G01N 2035/00752 bar codes
• CPC Class Codes: G01N 2035/1034 Transferring microquantities of liquid
• CPC Class Codes: G01N 35/00029 provided with flat sample substrates, e.g. slides G01N35/028 takes precedence
• CPC Class Codes: G01N 35/00594 Quality control, including calibration or testing of components of the analyser
• CPC Class Codes: G01N 35/00712 Automatic status testing, e.g. at start-up or periodic
• CPC Class Codes: G01N 35/025 having a carousel or turntable for reaction cells or cuvettes
• CPC Class Codes: G01N 35/10 Devices for transferring samples or any liquids to, in, or from, the analysis apparatus, e.g. suction devices, injection devices G01N35/0099 takes precedence
• CPC Class Codes: G01N 35/1004 Cleaning sample transfer devices
• CPC Class Codes: Y10T 436/112499 with sample on test slide

Abstract

A chemical analyzer includes a transport mechanism having a rotatable turntable adapted to hold a plurality of reagent test slides, a sample metering device, an incubator or temperature controller, a reflectometer and associated electronics and software. The rotatable turntable preferably holds up to twelve slides about its circumference, which slides are loaded onto the turntable by an inserter mechanism. The turntable positions the reagent test slides under the metering device, which device deposits a predetermined amount of sample onto each slide. The turntable also carries the slides above a reflectometer. After testing has been completed, an ejector mechanism automatically removes the reagent slides from the turntable.

Claims

1. A chemical analyzer, which comprises:

a test slide transporter, the test slide transporter including a rotatable turntable for holding a plurality of reagent test slides;

a slide inserter, the slide inserter being positioned adjacent to the circumference of the rotatable turntable for loading reagent test slides onto the rotatable turntable;

means for controlling the temperature of the rotatable turntable, the temperature controlling means including a heating element, the heating element being thermally coupled to the rotatable turntable to conduct heat from the heating element to the rotatable turntable, and a temperature sensor, the temperature sensor being thermally coupled to the rotatable turntable to conduct heat from the heating element to the rotatable turntable, and a temperature sensor, the temperature sensor being thermally coupled to the rotatable turntable;

a sample metering assembly positioned above the rotatable turntable for depositing a predetermined amount of sample onto each reagent test slide while the reagent test slides remain mounted on the rotatable turntable, the rotatable turntable being disposed for positioning the reagent test slides under the sample metering assembly;

a reflector, the reflectometer being positioned below the rotatable turntable, the rotatable turntable being disposed for positioning the plurality of reagent slides above the reflectometer;

a slide ejector, the slide ejector being positioned in proximity to the rotatable turntable for removing reagent test slides from the rotatable turntable; and

a cover mounted above the rotatable turntable, the cover being at least partially rotatable with respect to the rotatable turntable so as to cover and uncover the reagent test slides carried by the rotatable turntable.

2. A chemical analyzer as defined by claim 1, wherein the sample metering assembly includes a pipette assembly, the pipette assembly including a pipette for holding a predetermined amount of sample, a pump assembly, the pump assembly being coupled to the pipette assembly and providing air pressure to the pipette to force a predetermined volume of sample from the pipette onto the plurality of reagent test slides, and a pipette lifting assembly, the pipette lifting assembly being positioned above the plurality of reagent test slides for moving the pipette of the pipette assembly in a vertical reciprocating manner to allow the pipette to approach a reagent test slide and deposit a quantity of sample on each reagent test slide.

3. A chemical analyzer as defined by claim 1, wherein the reflectometer comprises a plurality of light emitting diodes, each light emitting diode emitting a light of a different frequency, the plurality of light emitting diodes being positioned below the plurality of reagent test slides and situated with respect to the plurality of reagent test slides to emit light on the plurality of reagent test slide;

at least one ultraviolet fluorescent light source, the at least one ultraviolet fluorescent light source being positioned below the rotatable turntable and situated with respect to the plurality of reagent test slides so as to emit an ultraviolet light onto the plurality of reagent test slides; and

at least one light sensor, the at least one light sensor being positioned below the plurality of reagent test slides to receive light reflected by the plurality of reagent test slides, the at least one light sensor providing a voltage which varies in correspondence with the light reflected by the plurality of reagent test slides.

4. A chemical analyzer as defined by claim 1, which further comprises a keyboard for inputting information regarding the tests to be performed by the analyzer and for controlling the operation of the analyzer, a display, the display providing test results and analyzer operational instructions to the user of the analyzer, a computer for controlling the operation of the analyzer, an interface circuit, the interface circuit being connected between the keyboard, the display, and the computer, and an analog-to-digital converter circuit, the reflectometer providing a signal to the analog-to-digital converter circuit, the analog-to-digital converter circuit converting the signal to a digital code signal which is provided to the computer for further processing.

44. A chemical analyzer as defined by claim 4, wherein the reflectometer further includes means for mounting the plurality of light emitting diodes and for mounting the at least one light sensor which receives light reflected by the plurality of test slides the mounting means having formed therein a plurality of first bores, the plurality of light emitting diodes being received by the plurality of a first bores, and a second bore, the at least one light sensor being received by the second bore, the first bores being arranged with respect to the second bore such that light emitted by the plurality of light emitting diodes will impinge on a test slide carried by the rotatable turntable, and at least one light reflected by the test slide will be received by the light sensor mounted in the second bore.

5. A chemical analyzer for analyzing reagent test slides onto which a fluid sample is metered, which comprises:

a rotatable turntable for holding a plurality of test slides in a circular arrangement;

means for inserting test slides onto the rotatable turntable, the slide insertion means being situated adjacent to the circumferential periphery of the rotatable turntable;

means for metering out a predetermined volume of fluid sample and for depositing the predetermined sample volume onto each test slide carried by the rotatable turntable while the test slides remained mounted on the rotatable turntable, at least a portion of the sample metering and depositing means being positioned in alignment with the test slides carried by the rotatable turntable;

a slide cover, the slide cover being positioned above the rotatable turntable and being at least partially rotatable relative to the rotatable turntable to cover and uncover test slides carried by the rotatable turntable;

a reflectometer, the reflectometer having a portion which is situated below the rotatable turntable and positioned in alignment with the plurality of test slides carried by the rotatable turntable the reflectometer including at least one source of at least one light of a predetermined wavelength, the light source being positioned with respect to the plurality of test slides carried by the rotatable turntable so as to direct light onto the plurality of test slides while the test slides remain mounted on the rotatable turntable, and further including at least one light sensor, the at least one light sensor receiving light reflected by the plurality of test slides carried by the rotatable turntable; and

means for removing test slides carried by the rotatable turntable, the test slide removing means being situated in proximity to the rotatable turntable to engage the plurality of test slides carried by the rotatable turntable and remove the plurality of test slides.

6. A chemical analyzer as defined by claim 5, wherein the rotatable turntable includes a top surface and a peripheral edge, and has formed in the top surface a plurality of recesses, the plurality of recesses being spaced apart from each other circumferentially about the rotatable turntable, each recess defining a receiving slot for receiving a test slide.

7. A chemical analyzer as defined by claim 6, wherein the rotatable turntable includes a plurality of receiving slot sidewalls, the receiving slot sidewalls being spaced apart on opposite sides of the receiving slots and partially defining the receiving slots;

and wherein the rotatable turntable includes a plurality of leaf springs, each leaf spring being mounted in a corresponding receiving slot and situated adjacent to a respective receiving slot sidewall, each leaf spring being resilient and exerting a force on a test slide received by the corresponding receiving slot to force the test slide against the corresponding opposite receiving slot sidewall.

8. A chemical analyzer as defined in claim 6, wherein the peripheral edge of the rotatable turntable includes a bevelled portion, the bevelled portion facilitating the mounting of test slides onto the rotatable turntable.

9. A chemical analyzer as defined in claim 6, wherein the rotatable turntable further includes a plurality of openings formed through its thickness, each opening being situated in a respective receiving slot, the opening allowing light from the at least one light source of the reflectometer to impinge on the plurality of test slides carried by the rotatable turntable.

10. A chemical analyzer as defined by claim 6, wherein the rotatable turntable further comprises a plurality of radially extending slots formed through the thickness of the rotatable turntable, each radially extending slot being in communication with a corresponding receiving slot.

11. A chemical analyzer as defined by claim 10, wherein the slide removing means includes a motor, an elongated member coupled to the motor, the elongated member being rotatable the elongated member being situated with respect to the rotatable turntable such that the elongated member, when rotated, partially extends through a corresponding radially extending slot of a slide receiving slot and engages a test slide carried by the slide receiving slot, thereby pushing the test slide out of its respective slide receiving slot.

12. A chemical analyzer as defined in claim 11, wherein the slide removing means further includes means for determining a first position of the elongated member, the elongated member position determining means including an optical sensor mounted adjacent to the elongated member when the elongated member is in the first position.

13. A chemical analyzer as defined by claim 6, wherein the slide cover is mounted on the top surface of the rotatable turntable and concentric therewith, the cover including a plurality of radially extending plate finger members, adjacent plate finger members defining a slot therebetween, the slide cover being at least partially rotatable relative to the turntable.

14. A chemical analyzer as defined by claim 5, wherein the slide insertion means comprises a guide plate, the guide plate including a surface having a recess formed therein to define a track, the track having a width which is at least slightly greater than the width of a test slide so that a test slide may be received by the track for loading onto the rotatable turntable;

and wherein the slide insertion means further comprises a slide inserter plate, the slide inserter plate being mounted on the guide plate and having a main body which is received by and reciprocatingly slidable in the track formed in the guide plate, the slider inserter plate exerting a force on a test slide placed in the track to move the test slide in the track in order to transfer the test slide from the slide insertion means to the rotatable turntable.

15. A chemical analyzer as defined by claim 14, wherein the slide insertion means further comprises means for determining at least a first position and a second position of the slide inserter plate relative to the guide plate.

16. A chemical analyzer as defined by claim 15, wherein the inserter plate position determining means comprises an arm which is mounted to and extends from a side of the main body of the slide inserter plate, the arm being L-shaped and having a downwardly extending leg portion, the guide plate further having an elongated slot formed through its thickness, the downwardly extending leg portion extending through the elongated slot and being reciprocatingly slidable within the elongated slot with movement of the slide inserter plate within the track.

17. A chemical analyzer as defined by claim 16, wherein the inserter plate position determining means further comprises a first optical sensor positioned alignment with the downwardly extending leg portion when the slide inserter plate is in the first position, and a second optical sensor positioned in alignment with the downwardly extending leg portion when the slide inserter plate is in the second position.

18. A chemical analyzer as defined by claim 14, wherein the slide insertion means further comprises means for orienting the test slides received by the guide track, the slide orientation means defining an opening and being disposed above the guide track, wherein test slides must pass through the opening of the slide orientation means prior to the test slides being positioned in the guide track.

19. A chemical analyzer as defined by claim 14, wherein the slide insertion means further comprises means for providing friction between the guide plate and the slide inserter plate.

20. A chemical analyzer as defined by claim 19, wherein the friction providing means includes a resilient leaf mounted on the guide plate, the resilient leaf being disposed to contact the slide inserter plate and exerting a force thereon.

21. A chemical analyzer as defined by claim 5, which further comprises means for aligning the slide cover with the rotatable turntable in a first position, in which test slides carried by the rotatable turntable are at least partially uncovered by the slide cover, and in a second position, in which test slides carried by the rotatable turntable are substantially covered by the slide cover.

22. A chemical analyzer as defined by claim 21, wherein the slide cover and rotatable turntable alignment means includes at least one pair of spaced apart detents formed in a surface of one of the rotatable turntable and slide cover, and at least one ball bearing mounted on the other of the rotatable turntable and slide cover, the at least one ball bearing being biased toward and cooperating with the detents of the pair to maintain the position of the slide cover with respect to the rotatable turntable.

23. A chemical analyzer as defined by claim 5, which further comprises means for partially rotating the slide cover with respect to the rotatable turntable.

24. A chemical analyzer as defined by claim 23, wherein the slide cover rotating means includes a first pin member fixedly mounted on the slide cover, a drive motor, a second pin member coupled to the drive motor and being movable upon energization of the drive motor, the second pin member being disposed with respect to the first pin member to engage the first pin member and cause the slide cover to rotate relative to the rotatable turntable.

25. A chemical analyzer as defined by claim 5, which further comprises means for maintaining the temperature of test slides carried by the rotatable turntable.

26. A chemical analyzer as defined by claim 25, wherein the temperature maintaining means includes a heater element and a heat sensor, the heater element and heat sensor being thermally coupled to the rotatable turntable.

27. A chemical analyzer as defined by claim 25, wherein the temperature maintaining means includes a heat spreader plate mounted on the underside of the rotatable turntable and thermally coupled to the rotatable turntable, the heat spreader plate having a recess formed in a surface thereof, a heater element mounted in the recess formed in the heat spreader plate, and a heat sensor, the heat sensor being at least partially mounted in a recess formed in the rotatable turntable and thermally coupled thereto.

28. A chemical analyzer as defined by claim 5, wherein the sample metering and depositing means includes a pipette assembly, the pipette assembly including a pipette having a main body and a tip portion removably mounted on an end of the main body, the tip portion defining a chamber for receiving and holding a fluid sample, and having an opening formed in an end thereof, the opening being in communication with the chamber, the main body having a bore formed therein and communicating with the tip portion chamber and opening, the pipette assembly further including a fluid conduit, the fluid conduit extending from the main body and being in communication with the bore.

29. A chemical analyzer as defined by claim 28, wherein the pipette assembly of the sample metering and depositing means further includes an electrical switch, the electrical switch being mounted on the main body of the pipette.

30. A chemical analyzer as defined by claim 5, wherein the sample metering and depositing means includes a pipette assembly, the pipette assembly including a pipette having a main body and a tip portion removably mounted on the main body;

and further including means for supporting the pipette above and in alignment with the test slides carried by the rotatable turntable.

31. A chemical analyzer as defined by claim 30, wherein the sample metering and depositing means further includes means for raising and lowering the pipette with respect to the test slides carried by the rotatable turntable, the pipette raising and lowering means including a motor, a rotatable cam member operatively coupled to the motor, a rocker arm having a first lever arm and a second lever arm, the first and second lever arms being angularly disposed to each other, the first lever arm engaging the rotatable cam member, and the second lever arm engaging the pipette supporting means.

32. A chemical analyzer as defined by claim 30, wherein the sample metering and depositing means further includes means for raising and lowering the pipette with respect to the test slides carried by the rotatable turntable, the pipette raising and lowering means including a motor, a first gear coupled to the motor, a second gear engaging the first gear, the second gear having an eccentric hub, a rocker arm having a first lever arm and a second lever arm, the first and second lever arms being angularly disposed to each other, the first lever arm engaging the eccentric hub of the second gear, the pipette supporting means including a collar fixedly supported in position above the plurality of test slides carried by the rotatable turntable, the collar having a bore extending therethrough, a pipette support ring received by and reciprocatingly slidable in the bore of the collar, the pipette support ring having an outwardly extending flange, the second lever arm engaging the flange of the pipette support ring.

33. A chemical analyzer as defined by claim 31, wherein the sample metering and depositing means further includes means for sensing a first position of the pipette with respect to the test slides carried by the rotatable turntable, the pipette position sensing means including a member mounted on and extending from the rocker arm and movable with the rocker arm, and an optical sensor positioned adjacent to the rocker arm extended member.

34. A chemical analyzer as defined by claim 30, wherein the sample metering and depositing means includes a motor, a rotatable lead screw operatively coupled to the motor, a member engaging the lead rotatable screw and movable in an axial direction with respect to the lead rotatable screw upon rotation of the lead screw, a syringe having a central bore, a plunger partially received by the syringe bore and reciprocatingly slidable therein, the plunger being mounted on the lead rotatable screw engaging member and movable therewith, the syringe being operatively coupled to the pipette assembly.

35. A chemical analyzer as defined by claim 34, wherein the sample metering and depositing means further includes at least one guide rode, the at least one guide rod being positioned in parallel with the rotatable lead screw;

and wherein the rotatable lead screw engaging member is mounted on the rotatable lead screw and engages the at least one guide rod, the at least one guide rod preventing the rotatable lead screw engaging member from rotating on the rotatable lead screw.

36. A chemical analyzer as defined by claim 34, wherein the sample metering and depositing means further includes means for sensing a first position of the rotatable lead screw engaging member, the first position sensing means including an optical sensor mounted adjacent to the rotatable lead screw engaging member when the rotatable lead screw engaging member is in a first position.

37. A chemical analyzer as defined by claim 5, which further comprises a bridge member, the bridge member being mounted over the rotatable turntable, at least a portion of the sample metering and depositing means being mounted on the bridge member.

38. A chemical analyzer as defined by claim 37, wherein the bridge member is pivotable between a first position, wherein it is positioned substantially horizontally over the rotatable turntable, and a second raised position, wherein it uncovers the rotatable turntable to facilitate access to the rotatable turntable and slide cover.

39. A chemical analyzer as defined by claim 5, wherein the at least one light source of the reflectometer is a fluorescence lamp;

and wherein the reflectometer further includes means defining an opening positioned adjacent to the fluorescent lamp, the opening defining means being positioned below the rotatable turntable and with respect to the test slides carried by the rotatable turntable such that light emitted by the fluorescent lamp will pass through the opening of the opening defining means and will impinge on a test slide and be reflected thereby, and a reference optical sensor, the reference optical sensor being optically coupled to the fluorescent lamp to receive light emitted by the fluorescent lamp.

40. A chemical analyzer as defined by claim 39, wherein the reflector further includes a filter, the filter being interposed between the fluorescent lamp and a test slide on which light emitted by the fluorescent lamp impinges, and a lens, the lens being mounted below and in alignment with a test slide carried by the rotatable turntable.

41. A chemical analyzer as defined by claim 40, wherein the reflectometer further includes a hollow cylindrical tube, the hollow cylindrical tube being interposed between the lens and the at least one light sensor which receives light reflected by the test slides.

42. A chemical analyzer as defined by claim 41, wherein the reflectometer further includes an optical stop, the optical stop being positioned in the hollow cylindrical tube.

43. A chemical analyzer as defined by claim 5, wherein the at least one light source of the reflectometer includes a plurality of light emitting diodes, each light emitting diode emitting a light of a different wavelength, the plurality of light emitting diodes being situated below the rotatable turntable and with respect to the plurality of test slides such that light emitted by the plurality of light emitting diodes will impinge on a test slide and be reflected thereby.