GB2068543A - Methods and apparatus for cleaning reaction vessels - Google Patents

Abstract

In automatic analysis apparatus in which photometric measurements are made through translucent wall portions of reaction vessels or cuvettes, there is provided a cuvette washing system for sequentially washing and testing the cleanliness of the reaction vessels or cuvettes. The cuvette washing system 10 comprises probes 22 depending from plate 24 which is associated with vertically movable plate 26. Oscillatable temperature measuring probe 40 may be included. Probes 22 are operable to evacuate each cuvette, to wash it, and to dispense into the washed cuvette a blank sample, when the optical characteristics are tested at the just completed test wavelength and compared with the stored results of that cuvette tested at the same test wavelength prior to the introduction of the sample and reaction fluids. If the vessel fails the comparison test, the analyzer will inhibit the use of the cuvette until it is cleaned again or until it has been replaced and passes the cleanliness test. Once the cuvette passes the comparison test at the old test wavelength, the cuvette is tested at the wavelength at which the next reaction in that particular cuvette will be tested and then the blank is removed and the cuvette dried by evacuating through a probe 22 in preparation for receiving the new sample and reaction fluids. The probes may have substantially the same outer configuration as the inside wall configuration of the cuvettes with the washing fluids flowing between the outsides of the probes and the inside walls of the cuvettes. <IMAGE>

Description

SPECIFICATION Methods and apparatus for cleaning reaction vessels The invention relates to methods and apparatus for cleaning reaction vessels and more particularly but not exclusively to cleaning the reaction fluids from a renewable supply of cuvettes or reaction vessels.

In a chemical analyzing system it is desirable to replenish the cuvettes such that an endless array is provided for operation of the analyzer. In such analyzers, it is preferable that the cuvettes or reaction vessels be renewed without physically replacing the cuvettes in the system while ensuring that the cuvettes are clean and not contaminated with previous reaction fluids. Further, it is preferable that these functions be handled in the smallest number of cuvette positions so that the analyzer is free to utilize the remaining positions to observe the reactions of the sample fluids placed in the cuvettes. Further, it is preferable that the cleaning and blanking operations operate automatically in the cleaning station.

The analyzers typically supply sample aliquots to the reaction vessels which are then monitored by measuring the absorbance of electromagnetic radiation at a particular wavelength or wavelengths by the fluids in the cuvette. Sample fluids placed in the cuvette typically may be body fluids related to a specific patient with one or more tests conducted on the sample fluids from each patient. Therefore, it is extremely critical that the cuvettes which are reused be clean and free from any carryover from the previous reaction fluids placed therein which generally would be from the sample fluids of a different patient.

An example of a chemical analyzing system is to be found in United States Patent Specification No. 4,234,538 (corresponding to British Patent Specification No. 2,000,284), the disclosure of which is incorporated herein by reference.

Disadvantages of prior art cuvette cleaning systems and techniques are overcome in accordance with a first aspect of the present invention by providing a cleaning and testing station which evacuates the expended fluids from the cuvettes, washes the cuvettes, tests the cuvettes at the completed test wavelength, inhibits the use of a cuvette if it fails the test and if it passes the test, tests the vessel and blank therein at a new test wavelength; removes the blank and dries the cuvette to prepare the cuvette for the new test fluids to be added therein. The cuvettes preferably are placed in an array which sequentially is moved through the cleaning and testing station to provide a substantially endless supply of cuvettes to the chemical analyzer.

According to a second aspect, the present invention concerns the evacuation and washing of each cuvette, adding a blank to the cuvette to test the cleanliness of the cuvette and removing the blank and drying the cuvette to reuse the cuvette with the next sample and reaction fluid in a chemical analyzer.

According to a third aspect of the invention, there is provided: A method of cleaning reuseable reaction vessels, each having an open top and a closed bottom, comprising: A. evacuating and washing a vessel in a cleaning station; B. dispensing a blank into said vessel; C. testing the optical characteristics of said blank and vessel at the last test wavelength; D. comparing the results of said test to predetermined limits based on the results of the last test at said test wavelength on said vessel in said cleaning station; and E. one of i. If it fails said comparison test inhibiting the use of said cuvette at least until it is cleaned again, and ii. If it passes said comparison test, testing the optical characteristics of said blank and vessel at a new test wavelength; and F. removing the blank and drying said reaction vessel for the new test.

2. A method as claimed in claim 1 including: evacuating and washing each vessel in a first wash position in said cleaning station; and evacuating washing and dispensing said blank into each vessel in a second wash position in said cleaning station.

According to a fourth aspect of the invention, there is provided: A washing apparatus for cleaning reuseable reaction vessels, each having an open top and a closed bottom, comprising: A. means for evacuating and washing a vessel in a cleaning station; B. means for dispensing a blank into said vessel; C. means for testing the optical characteristics of said blank and vessel at the last test wavelength; D. means for comparing the results of said test to predetermined limits based on the results of the last test at said test wavelength on said vessel in said cleaning station; and E. control means for one of i. if it fails said comparison test, inhibiting the use of said cuvette at least until it is cleaned again, and ii. if it passes said comparison test, testing the optical characteristics of said blank and vessel at a new test wavelength; and F. means for removing the blank and drying said reaction vessel for the new test.

By way of example only, illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a washing apparatus embodying the invention and a partial perspective view of a chemical analyzer; Figure 2 is a top plan view of the cuvette washer; Figure 2a is a top plan view of an oscillating element of the cuvette washer; Figure 3 is a front plan view of the cuvette washer; Figure 4 is a side plan view of the cuvette washer and a partial sectional view of a chemical analyzer and cuvette; Figure 5 is a rear plan view of the cuvette washer; Figure 6 is an enlarged side plan view of one of the wash probes of the cuvette washer; Figure 6a is a side plan view of the wash probe of Figure 6; Figure 6b is a bottom plan view of the probe of Figure 6;; Figure 7 is an enlarged side plan view of a cuvette drying probe of the cuvette washer; Figure 7a is a side plan view of the probe of Figure 7; Figure 7b is a bottom plan view of the probe of Figure 7; Figure 8 is a block diagram of one cuvette test arrangement of a chemical analyzer; and Figure 9 is a hydraulic schematic of the operations of one example of the cuvette washer.

Referring now to Figure 1, an apparatus constructed in accordance with the invention is designated generally by the reference character 10. The cuvette washer 10 is illustrated in operation with a chemical analyzer 12 (partially shown). The analyzer 12 includes a plurality of cuvettes or reaction vessels 14 which are at least partially translucent and are, for example, separate cuvettes placed into or molded into a rotor 16 of the analyzer 12. The rotor 16 can be rotated or indexed by, for example, a conventional drive mechanism (not shown) engaging a plurality of teeth or gears 18 on a periphery of the rotor 16.

The cuvettes 14 also could be mounted into a chain type drive which again could be stepped through the positions of the cuvette washer 10.

Preferably, the cuvette washer 10 and the rotor 16 are mounted on a baseplate 20 of the analyzer 12.

The cuvettes 14 or the cuvette positions each are identified with a separate location number 1, 2, 3, etc. up to the number of cuvette positions 14 in the rotor or other drive such as location number 120. Assuming that the rotor 16 is advanced in the direction shown by the arrow "A", then the positions 1 through 5, etc. and 120 are shown having passed through the cuvette washer 10 and are now ready to have new sample aliquots and reagents placed in them for respective tests to be preformed therein. The cuvettes 107, 108 and 109 are just approaching the first position in the washer 10 and will have expended reaction fluids therein to be evacuated therefrom, assuming they previously have passed through the fluid dispensing stations (not shown) after passing the cleanliness test in the cuvette washer.Even if empty, the cuvettes will be washed and tested before they are used.

The washer 10 includes a plurality of probes 22 depending from a probe mounting plate 24 to perform the various required functions of the washer 10. Each of the probes are connected through conventional fittings and coupled to the required supply and discharge lines, shown diagrammatically in Figure 9, but otherwise not illustrated.

As may best be seen in Figure 2, the mounting plate 24 is mounted offset on a drive plate 26; however, there is no criticality in the positioning of the plates 24 and 26 and the plate 24 can be made integrally with the plate 26 if desired. The only criticality is that the alignment of the probes 22 must be such that each of the probes will simultaneously fit within a separate one of the cuvettes 14 in the cuvette array whether it be on an arc as shown on the rotor 1 6 or in a different alignment in another type of analyzer. The mounting plate 24 is adjustably mounted on the drive plate 26 by a pair of screws 28. The mounting plate 24 includes a plurality of slots (not shown) in which the probes 22 are fitted.The probes 22 are fitted within the slots in the plate 24 with the tops of the probes being accessed through a plurality of apertures 30 in a probe retainer plate 32. The connections and lines (not shown) are aligned with and extend through the apertures 30. The retainer plate 32 is mounted to the mounting plate 24 by a pair of screws 34. The probes 22 are captured and prevented from coming out the front of the slots by a retainer plate 36 which is mounted to one of the plates 24 and 32 by a pair of screws 38.

It may be desirable to obtain a final temperature reading of the reaction fluids in the cuvettes when they reach the first position in the cuvette washer 10. In that case, a temperature probe 40 (best seen in Figure 3) is mounted in a tee-shaped plate 42 (Figure 2a) which has a slot 44 in which is rotatingly engaged an eccentric pin 46.

The eccentric pin 46 is driven by a motor 48 which is mounted on tip of the retainer plate 32.

As the motor is operated the temperature probe 40 is oscillated back and forth by the operation of the eccentric pin 46 engaged in the drive slot 44 in the tee-shaped plate which is retained in a groove or pair of tracks 49 in the plate 32 to oscillate the probe in the longitudinal direction in the cuvette 14. The oscillation of the temperature probe 40 overcomes any thermal barriers between the probe 40 and the fluids in contact therewith.

Typically, the probe will be a stainless steel probe with a thermistor sealed therein. The probe 40 will extend through a pair of aligned slots in the plates 24 and 32.

Referring now to Figures 1 and 3 through 5, the probes 22 and drive assembly of the cuvette washer 10 may best be described. The drive plate 26 is mounted on a pair of drive rods 50 and 52 which extend through a C or channel shaped drive housing 54. The housing 54 is preferably mounted to the base plate 20 or another fixture to which the analyzer 12 is mounted, such that the probes 22 are aligned directly above the cuvettes 14 for the operations described hereinafter.

The drive housing 54 includes an upper and a lower housing plate 56 and 58. The drive rods 50 and 52 extend through both the upper and lower plates 56 and 58 and are biased in an upward rest position by a pair of biasing springs 60 and 62.

The springs 60 and 62 respectively are mounted around the rods 50 and 52 between the upper and lower plates 56 and 58. The drive rods 50 and 52 include a transverse drive rod or pin 64 secured to or inserted through respective openings therein.

The pin 64 is preferably utilized to retain the upper portions of the biasing springs 60 and 62. The drive rod or pin 64 has a drive block 66 mounted thereon near the center thereof between the rods 50 and 52.

The drive block 66 has a drive shaft 68 of a pneumatic or hydraulic drive cylinder 70 screwed therein or otherwise secured thereto. In operation, the probes 72 are driven into respective cuvettes 14 by the actuation of the pneumatic cylinder 70 which retracts the shaft 68, hence driving the drive plate 26 and probes 22 downward into the cuvettes 14 as shown in Figure 4. The probes 22 are utilized to take the temperature, evacuate, wash, insert a blank, evacuate and dry each of the cuvettes 14 prior to the cuvette leaving the cuvette washer 10.

Referring to Figure 3, the first position optionally is the temperature probe 40, previously described, which measures the temperature of any fluids in the cuvettes 14.

A second one of the probes 22 is, for example, a wash and evacuating probe 72. This probe withdraws fluids from near the bottom of the probe with wash fluid being cascaded down around the probe to provide a turbulent washing action between the probe 72 and the inside of the cuvette 14. The probe 72 has essentially the same external configuration as the internal configuration of the cuvette 14, but is slightly smaller than the cuvette 14 to provide a scouring type action by the water flowing from the upper portion of the probe 72 to the bottom of the cuvette or vice versa. The details of the probe and hydraulic operation thereof will be described in Figures 6, 7 and 9.

The number of probes 72 is not critical, with the only criticality being that the previous reaction fluids be completely removed from each cuvette 14 before the next sample is introduced therein so that there is no carryover or contamination in the cuvette 14. As illustrated in Figure 5, there may be only one wash and evacuate probe 72 or there may be a second wash and evacuate probe 74 as shown in Figure 3. The wash and evacuate probe 74 will provide a similar wash and evacuate function as described with respect to the probe 72, but in the next or adjacent cuvette 14. Each of the probes 22 preferably, simultaneously is carrying on its respective operations in separate cuvettes 14.

The probe 74 is preferably operated to dispense the fluids from the bottom of the probe and evacuate them from near the top of the probe associated with the top of the cuvette 14. With this operation, when the wash cycle is over prior to stepping the rotor 1 6 to move the cuvettes 14 one position in the direction A (Figure 1), the water such as deionized (DI) water is preferably left on as the probe 74 is withdrawn to leave a predetermined amount of wash fluid in the cuvette 14. The fluid then can be utilized as a blank in the cuvette 14 during the time it takes for it to be stepped between the position of the probe 74 and that of a drying probe 76.

The drying probe 76 preferably also will have a configuration essentially the same as the internal configuration of the cuvette 14; however, it is preferable that the drying probe 76 remove the moisture from the bottom of the probe 76 and hence the bottom of the cuvette 14. Air will flow from outside the cuvette 14 around the probe 76 to suck all the moisture out of the cuvette 14 to prepare it for the next sample to be introduced therein after it is moved out of the cuvette washer 10. The testing of the blank in the cuvette 1 4 as it is stepped between the position of the last wash probe 72 or 74 and the drying probe 76 will be described with respect to Figure 8. The drying probe 76 also can be one or more probes as necessary or desirable.

The drive housing 54 preferably also includes a pair of optical readers 78 and 80 mounted on a back wall 82 of the housing 54. The optical readers 78 and 80 preferably will be convential U-shaped readers which generate a signal when the light path extending between the arms of the U is interrupted. The block 66 preferably includes an L-shaped extension 84 which will travel with the drive shaft 68 to activate the readers 78 and 80.

In the rest position the extension will block the reader 78 to provide a signal indicative that the cuvette washer 10 is in the uppermost rest position with the probes 22 removed from the cuvettes 14, so that the analyzer 12 can step the rotor 1 6 without breaking or damaging the probes 22 by the transverse motion of the rotor 1 6.

The extension 84 will block the light path in the optical reader 80 when them drive shaft 68 is fully retracted indicating that the probes 22 are in their lowermost position in the cuvettes 14. This signal is utilized to operate the functions of the probes 22 or can be utilized merely to check that the cylinder 70 is operating correctly.

One wash and evacuate probe, for example 72, is best illustrated in Figures 6, 6a and 6b. The probe 74 and other wash and evacuate probes are of an identical construction. The probe 72 has an upper mounting flange 86 which has a width greater than the width of an upper main body 88 of the probes 72. The thickness and width of the body 88 is substantially identical to the inside dimensions of the cuvette 14 being only sufficiently smaller to ensure that the probes 72 easily can be inserted into the cuvettes 14 and removed therefrom in operating the cuvette washer 1 0. The mounting flange 86 is wider than the slot in the mounting plate 24 and the retainer plate 32.When assembled, the plate 32 preferably bears against the top of the probe 90 and the plate 24 will bear by its upper surface on a lower flange portion 92 to secure the probes 72 in the cuvette washer 1 0.

Each of the probes 22 preferably includes a mounting flange 86 so that they can be mounted in a similar fashion in the cuvette washer 10. The probe 72 includes a lower body portion 94 having a width and thickness slightly smaller than the dimensions of the main body portion 88. The main body portion 88 includes a plurality of spacing ribs 96 extending from the main body 88 onto the lower body 94. At the bottom of the probe 72 are another plurality of spacers 98 having the same thickness as the ribs 96. The probes 72, 74 and 76 preferably are formed from a plastics material and the ribs and other portions 96 and 98 are molded therein as a unitary probe unit.

The probe 72 includes a plurality of passageways each communicating with the top 90 of the probe. A first central passageway 100 extends centrally through the probe 72 from the top 90 and opening at the bottom 102 of the probe 72. The passageway 100 has an upper recess 104 into which a fitting for the fluid line may be inserted. The probe 72 also includes a pair of outer passageways 106 and 110 which are bored or molded into the probe 72 and extend only part way therethrough. The outer passageways 106 and 110 terminate in a plurality of transverse openings 112, each passageway opening to three sides of the probe.

In operating the probe 72, the outer passageways 106 and 110 both will be coupled to a vacuum source or to a source of fluid with the center passageway 104 oppositely coupled to the source of fluid or the vacuum source. Describing first the operation of the probe 72 with the passageway 104 coupled to a source of vacuum and the passageways 106 and 110 coupled to a wash fluid source or sources, the probe 72 is inserted into the cuvette 14 preferably with the vacuum source coupled to the passageway 100 switched on before it arrives in the top of the cuvette 14 or with the source always on. As the probe 72 is inserted into the cuvette 14, the reaction fluids therein is sucked up the passageway 100 from the probe bottom 102.

Preferably, the probe 72 is inserted into the cuvette 14 so that the reaction fluids therein do not reach the bottom of the spacing ribs 96 and the top of the cuvette is above the openings 112.

The probe 72 can have the wash fluid pumped through the passageways 106 and 110 to flow down the sides of the lower body portion 94 between the walls of the cuvette 14 and the body walls of the portion 94 where it will be sucked up along with the reaction fluids through the probe bottom 102 through the passageway 100. The close spacing between the body portion 94 and the walls of the cuvette 14 ensure a turbulent scouring action to remove all the reaction fluids and foreign matter from the cuvette 14. Further, the spacers 98 are of a virtually minimal surface area so that they provide a virtually minimum surface area for fluid carryover or contamination of the next cuvette 1 4 in which they will be inserted.

The wash probe 72 preferably operates automatically by providing a pad or cuvette seal 114 (Figure 5) around an upper portion of the probe above the openings 112, which engages the top of the cuvette 14 and automatically draws the wash fluids through the openings 112 by the action of the vacuum source coupled to the passageway 100.

The probe 72 also can be operated in the opposite mode of operation by coupling the outerpassages 106 and 110 to the negative pressure source and the central passage 100 to the wash fluid source. In this case, the wash fluid passes through the passageway 100 exiting at the probe bottom 102 and rising along the walls of the portion 94 to exit through the openings 112 to the vacuum source or vacuum pump coupled thereto.

This operation preferably is done with the second wash and scavenge probe 74, which when provided with the sealing pad 114, automatically leaves the blank wash fluid aliquot in the cuvette 14 as it is withdrawn. The blank is left as soon as the seal is broken since, the fluid will stop flowing down the passageway 100, but there will be an amount left since the fluid is being evacuated from the upper openings or ports 112.

Referring now to Figures 7, 7a and 7b, the details of the drying probe 76 will be described.

The drying probe 76 is formed in a similar manner to the wash probe 72 and the same numbering will be utilized to describe similar elements of the probe 76. The probe 76 includes the spacing ribs 96 extending from the upper body portion 88 onto the smaller lower body portion 94. The portion 94 does not have the spacers 98. The probe 76 also does not include the sealing pad 114 and the passageway 100 is only connected to the vacuum source to evacuate the blank fluid from the cuvette 14, as well as to dry the cuvette prior to insertion of the next sample fluid.

Each of the probes 22 is preferably somewhat flexibly mounted in the cuvette washer 10 by inserting a flexible mounting pad 11 6 (Figure 4) between the tops of the probes 90 and the bottom of the probe retainer plate 32. Further, although the plate 32 has been shown as a unitary plate one or more of the positions are preferably on separately adjustable portions or plates to facilitate the alignment of the individual probes 72, 74 and 76, so that they easily will be inserted into and removed from the respective cuvettes 14.

Referring now to Figure 6, the photometric testing and control circuit is shown in a block diagram fashion. The chemical analyzer 12 typically includes a control 11 8 which determines whether the cuvette 14 is clean, that there is a cuvette located in the position, that the cuvette;is not broken or the light path therethrough otherwise obscured. As previously described, the cuvettes 14 provide a light path through at least a translucent bottom portion of each cuvette 14. For example, a light source 122 provides a beam of light 124 which passes through the cuvette 14 and any fluids therein each of which absorb a portion of the light resulting in a transmitted light beam 126 which is detected by a detector 128.

The detector 128 generates a signal indicative of the intensity of the light received from the light beam 126, which then is coupled on a line 130 to the control 118.

The transmitted light beam 1 26 preferably passes through a filter or filter array 1 32 which allows only the wavelength of interest to be received by the detector 1 28. In operation, the analyzer 12 reads each of the cuvette positions 1 through 120 both empty and with the blank fluid such as deionized water therein and stores each of the values received by the control 11 8 for the respective cuvette positions in a store or memory 134.The analyzer 12 then has a normal value for each cuvette 14 and each of the positions 1 through 1 20 stored in the memory 1 34. Each of the cuvettes in the positions 1 through 1 20 is tested and the value stored, since each of the cuvettes whether molded or separate from the rotor 1 6 have slightly different physical characteristics, different alignments in the rotor 16, different optical paths between the light source 122 and the detector 128 and different integration or measuring windows in the detector 128.

Thus in operation referring to Figure 3, a cuvette such as one in the position 109 arrives at the cuvette washer 10. In the first cycle or step the cuvette in position 109 is moved to be aligned with the temperature probe 40, if the temperature probe is being utilized. The cylinder 70 is activated and the probes inserted in their respective cuvettes with the probe 40 inserted in the cuvette 109 to measure the temperature of the reaction fluids in the cuvette if any have been placed therein. At the end of this cycle or step, the cylinder 70 is turned off and vented allowing the springs 60 and 62 to drive the plate 26 and probes 22 upwardly out of the cuvettes 14 or the cylinder 70 itself can be utilized to return the probes 22 to the uppermost position.The rotor 1 6 then is stepped one position and the wash probe 72 then is inserted into the cuvette in position 109 to evacuate the reaction fluids and to wash the cuvette with the Dl water to completely remove the reaction fluids from the internal surfaces thereof, so that the cuvette 14 can be utilized again for the next sample fluid.

In the next step the probe 74 is inserted, assuming that the probe 74 is being utilized, and the cuvette 14 is further washed until the end of that cycle wherein a quantity of wash water can be left in the cuvette in position 109 to serve as the blank fluid. A separate blank insertion nozzle also could be utilized. In the steps or cycles between the probe 74 and the probe 76, the detector 128 gencrates a signal on the line 1 30 which then is compared by the control 118 in a compare block or comparator 1 36 to determine if the cuvette in position 109 is clean as determined from the stored value for that cuvette position from the store 1 34. The value measured and the stored value are the same or within predetermined limits for the cuvette position 109 to pass the cleanliness test.

The filter 1 32 or filter array can be changed as the cuvette 14 is stepped from position to position or a plurality of light sources can be utilized which can be rotated independently on the rotor 1 6 at a different rate than the stepping of the rotor 16 to provide a plurality of detectors 1 28 each with different filters to obtain signals at different wavelengths of interest from each cuvette position. If the cuvette in position 109 passes the cleanliness test comparison between the value after it is washed and the value previously stored for it at that wavelength, the cuvette in position 109 will be evacuated by the drying probe 76.The cuvette than can have a new sample fluid inserted in it in the sample insertion position of the analyzer 1 2. The cycle then repeats itself the next time the cuvette in position 109 arrives at the cuvette washer 1 0. The cuvettes are evacuated whether they pass the cleanliness test or not.

If; however, the cuvette in position 109 does not pass the cleanliness test it will be noted by the control 11 8 and the analyzer 1 2 is inhibited from adding any sample fluid thereto. There are numerous reasons why the cuvette might not pass the cleanliness test on one passage through the cuvette washer 10, but then would pass the cleanliness test on the next passage through the cuvette washer 10 and therefore could then again be utilized by the analyzer 12. The detector 128 may not transmit the correct signal, the cuvette may not be properly washed, the light path itself may be momentarily biocked so that the cuvette would fail the test, but might pass the test the next time it has been passed through the cuvette washer 10.Preferably, each cuvette is tested at a plurality of wavelengths by one or more detectors 128 and both the wavelength of the test just completed is checked as well as the wavelength for the next sample fluid and test to be placed in the cuvette by the analyzer 1 2. This new test wavelength can be updated in the store 1 34 each time it is taken or it also just can be compared with the test results at that wavelength stored therein. By testing the cuvettes 14 several times, between the wash probe and the drying probe, transient errors can be eliminated.

The fluid circuit for the preferred embodiment illustrated in Figure 3, is shown in Figure 9. The washing and blanking fluid are preferably Dl water provided in a container or source 138. The vacuum or negative pressure is provided by a bellows or other high speed pump 140. The wash source 138 is coupled through a line 141 to a pair of lines 142 and 144 coupled respectively to the passageways 106 and 110 in the wash probe 72.

The wash source 138 is also coupled by a single line 146 to the passageway 100 in the wash and blank probe 74. Each of the lines is coupled through a check valve 148 to ensure that fluid does not flow back into the source 1 38.

The wash probe 72 has its passageway 100 coupled to the bellows pump 140 by a line 1 50.

The passageways 106 and 110 in the wash and blank probe 74 respectively are coupled to the vacuum pump 140 by a pair of lines 1 52 and 154.

The single passage 100 in the drying probe 76 is coupled to the pump 140 by a line 156. The probes 72 and 74 include the cuvette sealing pad 114 which seal the probes 72 and 74 into their respective cuvettes 14 in the cuvette positions 108 and 109 when they are driven into the cuvettes 14 by the mounting plate or platform 24 and the pneumatic cylinder 70. The drying probe 76 does not include a seal and each of the cuvettes 14 preferably has upperwardly inclined upper edges 1 58 which facilitate the insertion of the probes. In this system the source of deionized water 138 is coupled to the probes 72 and 74 and the vacuum or drain pump 140 is coupled to each of the probes and is left on so that the vacuum is maintained in each of the lines 1 50, 1 52, 1 54 and 1 56 at all times.The fluids removed through these lines are pumped through the bellows pump 140 to a drain 160.

This embodiment enables an automatic operation of the cuvette washer 10, because as the probes are inserted into their respective cuvettes 14 in the cuvette positions 108, 109 and 113, the fluids therein will immediately be sucked up through the vacuum lines upon contact with the fluids in the cuvette by the respective passageway openings. As the probes 72 and 74 are seated into the cuvettes in the positions 108 and 109, the pads 114 will seal the tops of the cuvettes and the pump 140 then will draw the Dl wash water through the check valves 148 and the respective wash lines to wash the cuvettes in the positions 108 and 109.

The probe 76 does not include a sealing pad and provides a high speed flow of air around the sides of the probe 76 to suck all of the moisture out of the cuvette in the position 113 to dry the cuvette. The vacuum source 140 also will draw the wash water around the sides of the probes 72 and 74 to provide a sheath flow closely confined between the probe and the walls of the cuvette which will turbulently pass therebetween to scour the cuvettes. The vacuum created by the sealing pads 114 also could be utilized to turn on a pump if desired to pump the wash fluid through the fluid circuit. The wash probe 72 essentially will completely drain the cuvette in the position 108 when the pad 114 is removed breaking the seal, since the vacuum is being applied at the probe bottom 102. The probe 74 at the same time is delivering fluid at the bottom of the probe through the passage 100 and removing it from the ports 112 of the passageways 106 and 110 spaced above the bottom of the probe. The probe 74 therefore automatically will leave a small predetermined amount of fluid to serve as a blank in the cuvatte in the position 109 when the seal 114 is broken as it is removed from the cuvette.

Many modifications and variations of the present invention are possible. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims (32)

1. A method of cleaning reuseable reaction vessels, each having an open top and a closed bottom, comprising: A. evacuating and washing a vessel in a cleaning station; B. dispensing a blank into said vessel; C. testing the optical characteristics of said blank and vessel at the last test wavelength; D. comparing the results of said test to predetermined limits based on the results of the last test at said test wavelength on said vessel in said cleaning station; and E. one of i. if it fails said comparison test inhibiting the use of said cuvette at least until it is cleaned again, and ii. if it passes said comparison test, testing the optical characteristics of said blank and vessel at a new test wavelength; and F. removing the blank and drying said reaction vessel for the new test.

2. A method as claimed in claim 1 including: evacuating and washing each vessel in a first wash position in said cleaning station; and evacuating, washing and dispensing said blank into each vessel in a second wash position in said cleaning station.

3. A method as claimed in claim 1 or 2 including: inserting a wash probe into said vessel having substantially the same external wall configuration as the internal wall configuration of said reaction vessel closely spaced from the walls of the vessel; turbulently flowing wash water between the walls of the probe and the internal walls of the vessel; evacuating said wash water and any remaining reaction fluids therein from the vessel; and dispensing a blank by removing said probe and leaving a quantity of wash water to serve as a blank therein.

4. A method as claimed in claim 1,2 or 3 including: inserting and sealing a wash probe into said vessel to automatically evacuate and wash said vessel and removing said wash probe seal to automatically dispense said blank into said vessel.

5. A method as claimed in any preceding claim including: taking the temperature of any reaction fluids in said vessel prior to evacuating and washing said vessel.

6. A method as claimed in claim 5 including: taking the temperature by inserting a temperature probe into said vessel and oscillating said probe to overcome thermal barriers between the probe and fluids in contact therewith.

7. A method as claimed in any preceding claim including: washing said vessel by turbulently flowing wash water in at least one confined sheath stream closely spaced from the inner walls of said vessel in a closed path from near one end of the vessel to the other.

8. A method as claimed in any preceding claim including an array of reaction vessels including: evacuating, washing and dispensing a blank into each vessel in a first wash position in said cleaning station; testing each vessel in a testing position; removing the blank and drying each vessel at a drying position; and passing each vessel in sequence through each of said positions.

9. A method as claimed in claim 8 including: inserting a wash probe into each said vessel in said first wash position having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the walls of the vessel; turbulently flowing wash water between the walls of the probe and the internal walls of the vessel; evacuating said wash water and any remaining reaction fluids therein from the vessel; and dispensing a blank by removing said probe and leaving a quantity of wash water to serve as a blank therein.

10. A method as claimed in claim 9 including: sealing said wash probe into the vessel when inserting it therein to automatically evacuate and wash the vessel and removing said wash probe seal to automatically dispense said blank into the vessel.

11. A method as claimed in claim 8 including: evacuating and washing each vessel in said first wash position; and evacuating, washing and dispensing said blank into each vessel in a second wash position in said cleaning station.

12. A method as claimed in claim 11 including: inserting a first wash probe into each said vessel in said first wash position having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the walls of the vessel; turbulently flowing wash water between the walls of the first probe and the internal walls of the vessel from the top portion of the vessel to the bottom of the vessel; evacuating said wash water and any remaining reaction fluids therein from the bottom of the vessel; inserting a second wash probe into each said vessel in said second wash position having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the walls of the vessel;; turbulently flowing wash water between the walls of the second probe and the internal walls of the vessel from the bottom of the vessel to the top portion of the vessel; evacuating said wash water and any remaining reaction fluids therein from the top portion of the vessel; and dispensing a blank by removing said second probe and leaving a quantity of wash water to serves as a blank therein.

13. A method as claimed in claim 12 including: sealing said first probe into each vessel when inserting it therein to automatically evacuate and wash the vessel; and sealing said second probe into each vessel when inserting it therein to automatically evacuate and wash the vessel and removing said second probe seal to automatically dispense said blank into the vessel.

14. A method as claimed in claim 13 including: inserting a drying probe into each vessel in a drying position having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the walls of the vessel and removing the blank through the bottom of the probe.

1 5. A washing apparatus for cleaning reuseable reaction vessels, each having an open top and a closed bottom, comprising: A. means for evacuating and washing a vessel in a cleaning station; B. means for dispensing a blank into said vessel; C. means for testing the optical characteristics of said blank and vessel at the last test wavelength; D. means for comparing the results of said test to predetermined limits based on the results of the last test at said test wavelength on said vessel in said cleaning station; and E. control means for one of i. if it fails said comparison test, inhibiting the use of said cuvette at least until it is cleaned again, and ii. if it passes said comparison test, testing the optical characteristics of said blank and vessel at a new test wavelength; and F. means for removing the blank and drying said reaction vessel for the new test.

16. An apparatus as claimed in claim 15 wherein said evacuating and washing means include: first means for evacuating and washing each vessel in a first wash position in said cleaning station; and second means for evacuating, washing and dispensing said blank into each vessel in a second wash position in said cleaning station.

17. An apparatus as claimed in claim 1 5 or 1 6 wherein said evacuating and washing means include: means for inserting wash probe means into said vessel, said probe means having substantially the same external wall configuration as the internal wall configuration of said reaction vessel and means for closely spacing said probe means walls from the walls of the vessel; means for turbulently flowing wash water between the walls of the probe means and the internal walls of the vessel; means for evacuating said wash water and any remaining reaction fluids therein from the vessel; and means for dispensing a blank by removing said probe means and leaving a quantity of wash water to serve as a blank therein.

18. An apparatus as claimed in claim 1 5, 1 6 or 1 7 wherein said evacuating and washing means include: means for inserting and sealing wash probe means into said vessel to automatically evacuate and wash said vessel and means for removing said wash probe sealing means to automatically dispense said blank into said vessel.

19. An apparatus as claimed in claim 15, 1 6, 17 or 18 further including: means for taking the temperature of any reaction fluids in said vessel prior to evacuating and washing said vessel.

20. An apparatus as claimed in claim 19 wherein: said means for taking the temperature include means for inserting temperature probe means into said vessel; and means for oscillating said probe means to overcome thermal barriers between said probe means and fluids in contact therewith.

21. An apparatus as claimed in claim 1 5, 1 6, 17, 18, 19 or 20 wherein said evacuating and washing means include: means for washing said vessel by turbulently flowing wash water in at least one confined sheath stream closely spaced from the inner walls of said vessel in a closed path from near one end of the vessel to the other.

22. An apparatus as claimed in claim 21 wherein said washing means include: probe means biased in a rest position above said vessel, said probe means having substantially the same external wall configuration-as the internal wall configuration of said vessel and adapted to fit therein; and means for overcoming said bias to insert said probe means into said vessel, said probe means including means for closely spacing the walls of the probe means from the internal walls of the vessel.

23. An apparatus as claimed in claim 1 516, 17, 18, 19,20,21 or 22 further including an array of reaction vessels wherein: said means for evacuating, washing and dispensing a blank into each vessel are located in a first wash position in said cleaning station; said means for testing each vessel are located in a testing position; said means for removing the blank and drying each vessel are located at a drying position; and including means for passing each vessel in sequence through each of said positions.

24. An apparatus as claimed in claim 23 wherein said evacuating and washing means include: means for inserting wash probe means into each said vessel in said first wash position, said probe means having substantially the same external wall configuration as the internal wall configuration of the reaction vessel and means for closely spacing said probe means walls from the internal walls of the vessel; means for turbulently flowing wash water between the walls of the probe means and the internal walls of the vessel; means for evacuating said wash water and any remaining reaction fluids therein from the vessel; and means for dispensing a blank by removing said probe means and leaving a quantity of wash water to serve as a blank therein.

25. An apparatus as claimed in claim 24 further including: means for sealing said wash probe means into the vessel when inserting it therein to automatically evacuate and wash the vessel and means for removing said wash probe sealing means to automatically dispense said blank into the vessel.

26. An apparatus as claimed in claim 23 wherein said evacuating and washing means include: first means for evacuating and washing each vessel in said first wash position; and second means for evacuating, washing and dispensing said blank into each vessel in a second wash position in said cleaning station.

27. An apparatus as claimed in claim 26 wherein: said first means include; means for-inserting first wash probe means into each said vessel in said first wash position, said probe means having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the internal walls of the vessel, means for turbulently flowing wash water between the walls of the first probe means and the internal walls of the vessel from the top portion of the vessel to the bottom of the vessel, means for evacuating said wash water and any remaining reaction fluids therein from the bottom of the vessel; and said second probe means include; means for inserting second wash probe means into each said vessel in said second wash position, said probe means having substantially the same external wall configuration as the internal wall configuration of the reaction vessel closely spaced from the internal walls of the vessel, means for turbulently flowing wash water between the walls of the second probe means and the internal walls of the vessel from the bottom of the vessel to the top portion of the vessel, means for evacuating said wash water and any remaining reaction fluids therein from the top portion of the vessel, and means for dispensing a blank by removing said second probe means and leaving a quantity of wash water to serve as a blank therein.

28. An apparatus as claimed in claim 27 further including: means for sealing said first probe means into each vessel when inserting it thereinto automatically evacuate and wash the vessel; and means for sealing said second probe means into each vessel when inserting it therein to automatically evacuate and wash the vessel and removing said second probe sealing means to automatically dispense said blank into the vessel.

29. An apparatus as claimed in claim 28 further including: means for inserting drying probe means into each vessel in a drying position, said probe means having substantially the same external wall configuration as the internal wall configuration of the reaction vessel adapted to fit closely spaced from the internal walls of the vessel and means for removing the blank through the bottom of the probe means.

30. An apparatus as claimed in claim 29 wherein: each of said means for inserting include drive means biased above said vessels and having said first and second wash probe means and said drying probe means mounted thereon, said drive means reciprocally mounted for movement of the probe means into and out of said vessels in tandem spaced from one another.

31. A method of cleaning reuseable reaction vessels, each having an open top and a closed bottom, the method being substantially as herein described with reference to and as illustrated by the accompanying drawings.

32. A washing apparatus for cleaning reuseable reaction vessels, each having an open top and a closed bottom, the apparatus being substantially as herein described with reference to and as illustrated by the accompanying drawings.