Analyzer featuring a circular track of cartridges centered on an incubator, and method of use

201~647 --2-ANALYZER FEATURING A CIRCULAR TRACK OF CARTRIDGES OENTERED ON AN INCUBATOR, AND METHOO OF USE FIELD OF THE I~TIO~ ;

This invention relates to an analyzer and a method ~or the economical a~aying of compon~nt8 of a body llquid, particularly deisigned ~or high volume throughput occupying a minimum amount o~ space.

BACKGROUND OE~ Large liquid analyzers such as the blood analyzers described in U.S.

Patent No. 4,512,952 have been very successful in testing body liquids using dried test elements isometimes identified as "slides".

One of the reasons for this has been the high throughput that such analyzers provide, and the high degree of accuracy and precision that i8 possible. On the other hand, there remain some minor disadvantages. These stem from the fact that there have been used in such analyzers, three different kinds of slide test elements ~ colorimetric end-point types, hereinafter "CM" types; rate types; and potentiometric types, hereinafter "PM" types. Each type has needed its own incubation and reading station. Examples are shown in, e.g., the aforesaid U.S.

Patent. Due to the need for three incubators and ~heir separate read stations, such analyzers have taken up considerable ~pace. ~urthermore, triplicating the incubators and read stations has added considerably to the cost.

A fur~her disadvantage of some analyzers has been the amount~of space required. E~ery time an additional ~unction is added, the apparatus for ~hat ¦ function has been simply "added on", producing a ! machine wherein no attempt is made to use space most efficiently.

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~3~ 201 4647 .

Japanese Kokai 61/209341 describes a rotating incubator, Fig. 5, which is said to be useful, p. 14, for CM type test elements or rate-type. However, PM types are not mentioned, nor are the test elements supplied from sources that provide for maximum utilization of space in the analyzer.

Therefore, prior to this invention, there has been the need for a blood analyzer having high throughput, accuracy and precision as in the abovenoted prior analyzer, but using fewer stations in a more efficient manner to require less room and less cost.

RELATED APPLICATIONS Commonly-owned Canadian Application ' 20 #8900611225 filed 09/13/89 entitled "Flexible Pusher ,i Blade and Housing", describes a pusher blade for , loading test elements from test-element cartridges , mounted to move along parallel paths.

The invention 3 therein is not claimed, however, as occupying concentric rings around a central incubator.

Commonly-owned Canadian Application #8900606811 filed 07/27/89 and #8900610546 filed ~ 09/07/89 and entitled "Reciprocating Transfer Mechanism j and "Incubator and Analyzer with Improved Cap Raising Means", respectively, provide for an incubator that will incubate both CM type and PM type test elements.

However, there is no disclosure of cartridges or their mounting means of any type to supply test elements to the incubator.

1 35 SUMMARY OF THE INVENTION 3 We have constructed an analyzer that allows all three of the above-mentioned types of dried test ¦ elements to be assayed on one incubator, and which ` solves the above-noted problems.

' .f-`; ' ~ ,~..!'.' , ``~ 201~47 More ~pecifically, in accord with one aspect of the invention, ~here i3 provided an analyzer for assaying for analyt2s of a body li~uid on dried test elements, the analyzer including means for temporarily storing a plurality of s~acks of dried test el2ments, the test elements in any one atack being for the same asxay while each stack i8 generally for a differen~ a~Qay selected from any one of potentiometric, colorimetric or rate-type test 10 elements, an incubator for test elements taken from a ~;

stack, and means for detecting a change in a test element after incubation in the incubator. The analyzer is improved in that it further includes means defining at least one generally circular, horizontal path generally centered on the incubator, first moving means for moving the ~tack-storing means around the at-least-one path, means for temporarily holding a ætack on the moving means, the holding means comprising being capable o~ at least two alternate states, one which holds a cartridge on the path and the other which releases a cartridge from the path, means for alternating the holding means between the two states, and means for transferring a test element to the incubator from any stack held on the path, whereby the incubator can be used to incubate all three types of test elements.

In accord with another aapect of the ~invention, that analyzer is improved in that the above-noted holding meanæ comprises a member mounted on the track to move between a first position that holds a cartridge for the stack and a second position that releases a cartridge, ~econd moving means being provided for moving the holding member between the two positions.

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201~6~7 --5- In accord with yet another a~pect of the invention, there i8 provided apparatus for temporarily storing a stack of planar, ~lide-like element6 in a predetermined vertical po~ition. The apparatus comprises meang defining at least one generally circ~lar, horizontal path and first moving means for moving a stack of elements around the at-lea~t-one path, mean~ ~or temporarily holding a stack on the first moving mF!ans, said holding means comprising a member mounted on the moving means to move between a first position that holds a cartridge for the stack and a second po~ition that releases a cartridge, and second movin~ means for moving the holding member between the positions.

lS In accord with still another aspect of the invention, there is provided apparatus for temporarily supporting a stack of planar, slide-like elements, in a predetermined vertical direction. The apparatus comprises a member configured to fit generally around a cartridge containing a stack of the elements, meang for moving the member along a generally circular path around a center, mean~ fitting under a cartridge ~or supporting a cartridge, and means for slidably moving the supporting means between two position~ on a radius of the circular path, one of the positions being one in which the supporting means are too close together to allow a cartridge to fall bet~een them, and the other of said ~;

pogitions being one in which the cartridgesupporting means are far enough apart to cause a cartridge to fall between them.

A ~urther aspect of the invention comprises a method ~or supplying a test element from any one of three different kinds to an incubator. This method 3s comprlses the steps o~ ''~ . ., .

..... .... , .: . - . . ~ . . .. . . . . . .

20~47 --6 supplying slide-like test element~ selected -:

~rom CM-type, rate-type, and PM-type elements9 a~ a plurality of stacks ~herein the test el~ments of each stack are identical within the stack, mounting the stacks on at least one generally circular path sur:rounding a central lncubator, moving the stacks around the path until a selected stack reaches a predetermined position, nd transferring a test element fro~ the stack at the predetermined position to the incubator.

Accordingly, it is an advantageous feature of the invention that an analyzer for all three types of test elements i3 provided that minimizes the space needed, without sacrificing through-put.

It is a related advantageous feature that such an analyæer is laid-out in a highly efficient configuration that requires less space.

It is another advantageous feature of the ~ :

invention that apparatus and a method are provided for efficiently and easily loading any one of three different kinds of test elements into a single incubator.

Other objects and advantages will become j~ apparent upon reference to the following description of the preferred embodiments, when read in light of the attached drawings.

BRIEF DESCRIPTION OF T~E DRAWINGS Figure 1 is a perspective view of an ~:

3~ analyzer constructed generally in accordance with the invention;

F:igure 2 is a partially schematic, plan view depicting the general arrangement of the part3 of the analyzer, the cover and rotor of the incubator having been removed for clarity;

Figure 3 is a fragmentary perspective view of a portion of the cartridge-mounting means of the .. ~ ¦ invention, nesting frames having been removed for .~ ` ~ clarity; ~- 20~46~7 ,..~ Figure 4 iB a fragmentary e~ploded section view taken generally along the line IV-IV of Figure 3, with the nesting frames added;

Figure SA is Pragmentary section view taken generally along the line VA-VA of Figure 4;

Figure 5B i8 a frag.mentary sectlon view taken generally along the line VB-VB of Figure 4;

Figure 6 i~ a section view taken generally along the line VI-VI of Figure 5;

Figure 7 i8 an exploded ~ection view taken generally along the line VII-VII of Figure 6, but without the ~pring (for clarity~;

Figure 8 ig a fragmentary elevational view in section, taken from behind transfer device 400 a~ 15 ~een in Figure 1, illustrating the cartridge-mounting ~ ~:

means assembled in place to cooperate with a pusher ;:

blade of device 400 to dispense test elements to the incubator;

Figure 9 is a fragmentary elevational view in section similar to Figure 8, but illustrating tbe parts in the cartridge-release position; :

Figure 10 is a fragmentary elevational view similar to a portion of Figure 8, but illustrating an alternate embodiment;

Figure 11 is a fragmentary plan view taken generally along the line XI-XI of Figure 10;

Figure 12 i8 a fragmentary elevational view similar to that o~ Figure 10, but of yet another ~.

alternate embodiment;

Figure 13 i8 a fragmentary elevational view ~.

in section of a`mechanism for loading cartridge~ into the mounting means ~hown in Figure 8; :~ :

Figure 14 is a fragmentary elevational view : :

in section of a pu~her blade, housing and drive ~eans ..

useful with this invention;

Figure 15 i8 a fragmentary elevational view ..

in ~ection of an incubator u~eful in this invention;

2~14647 -8Figure 16 i8 a fragmentary plan view looking up, of a mechanism for unloading cartridges from the mounting means shown in Figure 8, uaing the doors partially shown in Figure 10; and Figure 17 i~ a schematic illustration of a preferred re~lectometer useful in the invention.

DESCRIPTION OF T~ PR~E~ED E~BODIM~ The invention i8 hereinafter de~cribed in . detail with respect to preferred embodiments featuring certain kind~ of dried test elements, and preferred specific mechanisms a) for supplying and dispensing body liquid for assaying, b) for unloading test elements from cartridges, and c) for incubating -such test elements after body liquids are dispensed thereon. In addition, the invention is useful regardless of the chemistries u~ed in the drled test elements, and the type of cartridge, and regardless ~of the body li~uid assayed or the specific mechanisms contributing the noted functions of supplying and dispensing body liquid, and unloading and incubating test elements.

I Orientations such as "up", "horizontal", "level" and the like are used herein with respect to the orientations preferred during normal usage.

The preferred test elements for use in this invention are the dried test elements identified in patent3 such as U.S.

Patent Numbers 4,336,091 (PM - type), and 3,992,158 and 4,258,001 (for both ~ ~ CM-type and rate type).

Useful elements also include ` ~all three noted types as they are available under the trademark "Ektachem" slides from Eastman godak ! - Company.

The test elements are provided as stac~s within the storage means described below, each ~tack preferably comprising identical test elements for a single assay. Any method of providing r~uch stac~s is :

2~146~7 _9_ useful. Preferably, each ~tack i8 housed in a cartridge, the term hereinafter used. Most preferably, such cartrid~es ,are constructed a~ described in any of U.S.

Patlent Numbers Re. 30,595;

5 4,187,077; 4,151,931; and 4,190,420. Additionally, the cartridges available under the trademark "Ektachem" slide cartridges for ~pecific a88ay6, from Eastman Kodak Company, can be used.

In accordance with the invention, analyzer 20 compri~e~, Figures 1 and 2, means for temporarily storing a plurality of stacks of test-elements are ~ provided in the form of cartridges C. Means are further provided to define at least one, and preferably two, concentrically disposed paths 22 and 24, preferably centered on point c, Figure 3, the center of the incubator and of the analyzer. That is, each path 22 or 24 extends around a single incubator 500 that i8 disposed 80 as to be generally centered within the paths, thus optimizing the use of space in the analyzer. A cartridge-loading station 300, Figures l and 2, i8 disposed above the paths to one side of incubator 500. An electrometer 360 i8 di~posed above the paths at another side of incubator 500, and a test-element transfer device 400 i8 provided above the paths at yet another side of incubator 500 to load a test element into incubator 500 from any cartridge on the paths. A stationary support surface 510 is provided as an annular ring between path 24 and incubator 50Q, to cooperate with ;

a liguid-di~pensing probe, described hereinafter.

The analyzer controls, not shown, comprise one or more microprocessors connected to suitable input and output device3, as is conventional.

Referring more specifically to paths 22 and 24, each of these is separately housed within a ~rame comprising fi~ed exterior ~alls 26 and 28, ;~ ....... . ~ .. : : . . . . . ., . .. . , :, .. - .. . .. . .

201~647 --10-respectively, Figures 1 and 8. Mo~t preferably, walls 26 and 28 can be combined to provide a single common wall 28' between the paths, Figure 8.

To move car~ridges around each path, within each housing for each path, an annular ring 30 or 32 i8 rotatably mounted, Figur~es 3-5 and 8. ~ollower ~ollers 34 or 36, respectivlely, are strategically placed on frame portion 37 of the analyzer, ~igure 4, to partially constrain the rings on the horizontal and vertical directions. The final constraint i8 a drive motor 38 or 40, respectively, Figures 3 and 4.

Each drive motor is biased by a conventional spring 42, Figure 4, mounted on a frame member 43 of the analyzer to exert a radial force F2 or Fl against the ring, Figures 3 and 4. The drive connection is via a ring gear 44 mounted on the outside of ring 30 and the inside of ring 32, and a pinion gear 46 on the drive motor. Motors 38 and 40 are preferably conventional pitch-line motors-that is, in addition to the pinion gear, there is a smooth roller 48 mounted integrally with and above the pinion gear, and the radius "r", Figure SA, of this roller is adjusted to insure that teeth 50 of the pinion gear always engage teeth 52 of the rin~ gear on the pitch ` .

line. Additionally, each motor 38, 40 preferably includes a rotating disk 54 that provides underlying vertical support of the ring, Figures 3 and 4. :~ Each of the rings 30 and 32 has cut-out ;~ portions 60 shaped and sized to accommodate a test-element cartridge, Figure 8. In ring 30, thirty-five such cut-outs are preferably placed, with a fewer number in ring 32, Figure 3.

In accordance with another aQpect of the invention, holding means are included with each of paths 22 and 24, and with each ring 30 and 32, to temporarily hold a cartridge on the ring, preferably in a vertical orientation. The holding means are ~, 20~4647 con~tructed to opera~e between at least two alternate s~ates; one o~ which holds the car~ridge~ as noted, and the other of which release~ the cartridge from the ring, pre~erably to fall away from the ring.

! 5 Any ~uch holding means can be used. ~ighly :

~ preferred i8 one which csoperates with the upper portion of each ring and ~hich moves with respect thereto to release a cartridge.

More specifically, an upper, horizontal support surface 61 iB provided lO on each ring around each cut-out portion, Figure 4.

Sidewall 59 of each cut-out 60 i8 generally orienged radially with respect to the center of ring 30 or 32, Fi~ure 3.

As seen in detail in plan, Figure 6, each cut-out portion includes at the outer end, a pair of 15 shoulder~ 63 projecting out into the overall area normally occupied by a cartridge's upper end, Figure 8.

At ~he inner end of the cut-out, two diagonally ~haped guide flanges 65 sre provided, Figures 4 and 6.

Shoulders 63 thus act as meanQ for holding vertically a cartridge, when such shoulders are correctly spaced with respect to a nesting frame member discu~sed hereinafter.

Most preferably, the cartridges are temporarily held in each ring by "hanging" them in .

25 the cut-out portions, Figure 8. A preferred form of :

such holding or "hanging" means comprises nesting frame members 62 for each cut-out portion, Figures 4 and 6-8, that cooperate with shoulders 63. More specifically, each such ne6ting member 62 comprises a generally rectangular frame having two generally vertical side wàlls 66,68 and two generally vertical end walls 70, 72, Fi&. 4. Each side wall has preferably two projections 74, Figures 4 and 6-7, that serve to ride on the upper supporting surface 61 of the ring, Figure 7, to keep frame member 62 from falling through cut-out portions 60. In additisn, each side wall preferably includes two spring fingers ':'',,~ ;

2Q14~7 -1276 that have a latch shoulder 78, Figure 5B. The finger~ are biased outwardly to relea8ably hold frame mem~er 62 ~ithin cut-out portions 60.

To provide part of the mean~ vertically :

supporting a cartridge, end wall 70 includes at least one and preferably a pair of cartridge ~upport ~houlders 80 with a supporting surface 82, Fig. 6.

Surface 82 is positioned below top surface 64 of frame member 62 a distance "h", Figure 4, that equals 10 the distance from top surface 64 to support sur~ace : :

61 of rings 30 and 32. Shoulder 80 and surface 82 thus project into cut-out portion 60 at generally the same horizontal level as surface 61.

When the ~:

opposite end wall 72 i~ pushed over the exposed ~houlder 63 of surface 61, ~urface 82 of nest frame 62 i8 thus aligned and coacts with surface 61 of shoulder 63 to hold up a cartridge, Figure 8. : Opposite end wall 72 includes a ~: :

downwardly-depending pusher lip 84, Figures 4 and .

7-8, that cooperates with override means 36 mounted on common wall 28~ and wall 26 of the paths, Figure 8.

The means 86 can be a ~olenoid, as shown, or a motor-actuated lever, or any automatic conventional actuator.

To bias the nesting frame into the "normal~ or "hanging" position shown in Figure 8, spring means are mounted from end wall 70, Figure 4.

Most preferably, the spring means comprise a compression leaf spring 90 having two interior legs 92, Figure 6, connected to a body portion 94, from which protrudes upwardly a middle leg`96, Fig. 4.

The ends of legs 92 engage apertures 98 of end wall 70, Figures 6 and 7, whereas the end of leg 96 rests on surface 61 at~ ::

position 99 between the two guide flanges 65, Fig. 4. .

Alternatively, spring 90 can be an integral part of frame 62.

2~4647 -13 In use, Figure 8, ~pring 90 (~hown schematically in this Figure) ~normally~' biases nesting frame 62 towards the outside of the ring, generally along a radius of the ring, 80 that one edge of cartridge C is supported or ~hung" by æhoulder surface 63 of the ring, and the other is supported by shoulder 80 of nesting frame 62. The exception occurs when overrlde means 86 i8 actuated in either path 22 or 24. When that occurs, arrow 101 of Figure 9, ne~ting frame 62 i~ moved leftward to compress spring 90. The upper lip of cartridge C is pushed off eurface 61 at lip 63 by ieftward-moving lip 84 of nesting frame 62. as the frame 62 -~ continues to move leftward, the opening between oppositely-paired shoulders 80 and 63 gradually increases until the spacing ~IWll is sufficient to - allow cartridge C to fall through, arrow 103.

Complete exiting of this cartridge from the ring requires, however, the actuation of an exit door 326, discussed hereinafter.

Alternatively, (not shown), cut-outs 60 and frame members 62 could be rotated 90 80 as to slide relative to each other (to hold or release a cartridge) along an arc, that is, along a portion of ?5 the path traversed by the ring carrying the frame.

Notches 105 are preferably included on the outside flange edge of ring 32, and the inside flange edge 107 of ring 30, Figure 3, to allow a sensor (not shown) to sense that a particular cartridge is in fact at a particular location, e.g., the cartridge load/unload station 300. Most preferably, each notch is aligned with the middle of the corresponding eut-out portion 60, Fig. 4, although other locations are also useful. (Only a portion of flange edge 107 ~ is shown in Fig. 3.) Each of the cut-out portions 60 can be tracked by the analyzer by flagging one of them as a home position, as is conventional, and then counting the number of offsets from "home~.

' ~ 201~6~7 Still further, the holding member for the cartridges need not be a full frame that sits and moves within cut-outs in the ring. Instead, as shown in Figures 10 and 11, it can be ~imply solenoid-actuated finger~ that hold up the cartridge. Parts similar to those previously described bear the same reference numeral, to which the distinguishing suffix A is appended.

Thus, each ring such as ring 30A can have cut-out portions 60A, that are larger in their interior dimensions, Figure 11, than the outside dimensions of the upper end of cartridge C. As a result, none of surface 61A surrou~ding the cut-out portions 60A is used to support the cartridge.

Indeed, except for the fingers hereinafter described, cartridge C would fall right through the opening of ! portion 60A.

In this embodiment, the cartridge-holding means comprise oppositely disposed fingers 110,112, actuated by solenoids 114,116. When in the solid position shown in Figure 10, the fingers are extended and hold up a cartridge. When withdrawn to the dotted position, arrow 118, they are separated tov far apart to hold a cartridge, so that gap G causes the cartridge to fall through. Alternatively, not shown, one of fingers 110 and 112 can be fixed in the extended position and the other withdrawable a sufficient distance as to create said gap G.

Such solenoid-activatable fingers require a brush-less connection between the rotating ring and a power source. Alternatively, the fingers 110 and 112 can be pivoted so as to be cammable between two ~ positions by a solenoid mounted on the stationary !' i frame.

Parts similar to those previously described J bear the same reference numeral, to which the , 35 distinguishing suffix B is appended.

Thus, ring 30B has a cut-out portion 60B, ~, Fig. 12, through which a cartridge C will fall, as in Figure 10, except for opposed fingers llOB and 112B that are pivotably mounted at 119 to move between two .

20~647 -15alternate 8tate8.

In one state, as ~hown in 301id lines, they project into ~he path of the cartridge to catch and hold the cartridge. The fingers are right-angled, with one end 120 locatable under the cartridge and opposite end 122 positioned 90 around and below pivot 119. Spring bia~ing means 3uch as a compression ~pring 124, or a torsion spring, preferentially hold fingers llOB and 112B as ~hown.

However, when ring 30B iR positioned at the cartridge unload station 300, Figure 1, the fingers pass by solenoids 126,128 mounted on the stationary frame, Fig. 12. Such solenoids include arms 130 that are in position to pa~s outwardly beyond ends 12~, without disturbing them, but al~o to press outwardly against ends 122, arrows 132, forcing the fingers to pivot, arrow~ 134, to the phantom positions. This in turn cause~ the ~ingers to release the cartridges C, which ~hen fall out of position in the ring. A trap door in station 300, describcd hereafter, allows the falling cartridge to be completely released from its track housing.

Alternatively (not shown), paths 22 and 24 can be defined by circular tracks on which a train of member~ 62 is caused to ride.

An electric motor suitably connected to the analyzer controls can drive such a train on such a track.

To load and unload cartridge with respect to each of paths 22 and 24, load and unload station 300 is provided. Figures 1 and 13. Station 300 comprises a housing 302 that its on the housing of the two paths, Figure 13. An opening 304 and 306 i9 formed in the top ~urface of housing 302, Fig. 1, each positioned to be aligned with an aperture of the ring below ;t, when the ring is appropriately centered. Positioned below opening3 304 and 306, Figure 13, is a horizontal wall 310 with an aperture 312 that can be made to be in alignment with cut-out 2~4~47 -16portion 60 of the ring, and that i~ aligned with opening 304 or 306. An annular ~houlder 314 ri~es from aperture 312, on which a bar cvde reader 316 is mounted. The bar code reader can be conventio~al, and i8 positioned to ~can a bar code on an incoming cartridge, as shown.

Aperture 312 i8 normally closed by a door 320 operated automatically by a motor 322 and any suitable linkage 324 between door 320 and its motor. When an empty portion 60 in ring 32 i~ positioned in place as sho~n, wi~h a cartridge Cl in position on door 320, motor 322 i8 actuated to open the door. Cartridge C' falls into place into ring 32, aæ ~upported by the structure described for Figure~ 6-12. Ring 32 can then be advanced to move a cartridge into place at the transfer device 400.

Spent cartridges, on the other hand, are removed by using door 326, described hereinafter.

To transfer a test element from a ~tack of elements E or E' in a cartridge C, device 400 is uYed, Figure~ 1, 8 and 14. Referring especially to Figure }4, such a device ~eatures a housing 352, and .

movable within a slot 350 ln housing, a pusher blade 414. Any kind of pusher blade iB useful, but the fol~owing is preferred: All of blade 414 is ~lexible, except for the front end 412, which is rendered rigid by one or more ribis 416 that extend along the length of the blade. The flexible portion of the blade featureiR notches or a rack 426 that mate with a pinion gear 432 driven in portion 430 of hou~ g 352. As a result, the fle~ible portion of blade 414 can bend through the curve of slot 350, caused by housing 352 to have a radius of curvature R. This in turn minimizes the lateral space occupied by device 400, Fi8ure 1.

:s , ,:~ ,~ ~: ~ 20~ 4647 -17- :.. Blade 414 follows path 198 above the stacks of elements E or E~ presented by cartridges C or C~.

These are in turn alternatively moved up into the page 198, arrows 470, 472, or down, depending on which type of element is desired.

The cartridge in turn is selected by rotating the holding rings (not shown in Figure 14) about incubator 500 and stationar~r surface 510.

Referring again to Figure 8, it is desirable that the atmospheres for rings 30 and 32 be controlled, and further, that they be controlled separately. For example, relative humidity can be controlled by any mechanism. For most of station 20, this is easily done by wall 28' being a complete barrier between the two paths 22 and 24. However, as described and claimed in commonly-owned Canadian Application #0002036725 filed 02/20/91 entitled "Analyzer Having Humidity Control Apparatus", to keep the atmospheres different, intermixing of atmospheres needs to be prevented when each path necessarily intersects the blade path 198.

Thus, it is desirable that a seal be maintained at the top, in conjunction with the blade passage, to ensure that there is minimal air mixing between the two paths 22 and 24. A preferred embodiment to achieve these results is as follows:

The top portion 201 of the housing accommodates the passage of blade 414 and a test element dealt off the top of a stack from ring 30 or 32.

More specifically, top portion 201 has a blade entrance port 202 and an exit port 204 fixed in the housing, and floating members 210, 212.

The floating members are displacably seated on annular valve seats 214 disposed around an opening 216 that will allow a cartridge to be raised up into the path 198 to be :; :

; ` 2~14647 -18 engaged at groove 217 by blade 414. Members 210 and 212 are each biased downwardly against 8eat8 214 by an expansion ~pring 218. Because each member 210 or 212 serves a~ a ~ubstitute blade guide if itB cartridge i8 not rai~ed up, a ~roove 220 horizontally extends through the member. Because each member i~ pu~hed up out of blade path 198 if its cartr;dge is rai~ed up, a space 228 is formed in portion 200 to accommodate member 210 or ~12 when spring 218 iæ compressed. (Movement upward of a stack elements E by rod 234 al80 causes cartridge C to be raised up against member 210 and 212.) Although not essential, member 210 or 212 can be con~tructed so that top portion 230 thereof, from which boss 231 extends to receive spring 218, can be easily removed from bottom portion 232 (not shown), whereby any test element jams can be readily fixed.

' ~lements E or E' are transferred by device 400 to support surface 510, Figures 1 and 8, where a dispensing probe 550, Fig. 8, is used to dispense a patient sample onto the te~t element 80 transferred.

Any such probe 550 can be used, including those automated probes conventionally used on analyzers available under the trademark "Ektachem E-700" Analyzer from Eastman Kodak Company. ' ~;

The manner in which the sample is obtained by the sample-dispensing probe is not critical to this invention. The ~ample dispensing probe preferably.includes pre~surizing means, not shown, which can be in'tegral with the rest of the analyzer described herein, or it can be provided by a separate stand-alone sample supply station that i8 coordinated to act in conjunction with thi~ analyzer. For example, the sample-dispen~ing means and the m~chanisms for loading it, described in -19- 201 q6~7 ...";

commonly-owned Canadian Application #8900593733 filed by James Shaw on 03/15/89 and entitled "Analyzers Using Linear Sample Trays with Random Access" can be used.

' In any event, any convenient apparatus for moving the probe from the sample location exterior of analyzer 20, to station A, arrow 560, Figure 1, can be used.

A dispenser (not shown) similar to 550 is used to dispense reference liquid onto a PM element, at the same location at station A as is used by probe 550.

Such reference liquid dispenser is preferably conventional.

The probe first moves ho~izontally, arrow 560, Figure 1, from another portion of the analyzer handling patient samples, not shown, or from a different apparatus that supplies such samples to position "A". The probe then moves downward, arrow 562, Figure 8, to be in position to dispense the sample.

' Thereafter, blade 414 from device 400 pushes the test element further, arrow 570, into incubator 500, Figure 1.

i ~urning next to incubator 500, it is ,~ preferably a rotating incubator with stations around its circumference each for holding a test element. Any l such incubator can be used, there being a variety that ¦ 30 are known in the art.

Most preferably, it comprises, Figure 15, an incubator of the type described in commonly-owned Canadian Application #8900611227 filed 09~13/89 entitled "Universal Evaporation Cover".

More ~ specifically, incubator 500 preferably has a rotor 604 ~;

journaled at 612 on a shaft 614. Appropriate heating ~ elements, not shown, are dispersed throughout incubator j 500.

Of the plurality of stations formed in the rotor, station A' is depicted. A spring 620 is captured at the station and is biased to press down on a cover 640 with a .

~, ,~r,i 20~L~6~7 -20force F. Such a spring comprise~ a cover - engaging leg 621, a bias leg 622, and a vertical leg 624, leg 622 being captured behind a ridge 628 o~ rotor 604.

A bos 8 650 can be mounted on the top of cover 640 to releasably engage an aperture 652 in leg 621.

Vertical leg 624 rests on a support plate 662 that i8 apertured at 664 for the reading of colorimetric or rate-type test elements. Plate 662 i8 al80 the support of the test elements E and E~, at the other stations. The undersurface of plate 66~ ix caused to ride over three gpaced-apart buttons 670, in stationary surface 672, apertured at 666. The buttons are positioned to carefully control the height of the test element vis-a-vis a re~lectometer 6~0, positioned to read a test elemen~ through apertures 664 and 666. Sensor 682 and flag 684 can be used to accurately sense when the station are in their correct positions, e.g., for reading. As is conventional, reflectometer 680 preferably comprises a light source 686 and a detecting station 688 that senses the reflected light, arrow 690, from element `~ E'.

In order for single incubator 500 to be acceptable for all three kinds of test elements (CM, rate and PM), incubator 500 is preferably modified in several ways to accommodate all three. For example, read station, so that the reflectometer is mounted to read rate and CM test elements while still on the incubator. Because each station at the incubator may have any one of the three types of test elements present, portions such as the evaporation cover at ~ each station are modified so as to be effective regardless of the type of test element present.

Becau~e some CM elements may involve end-point chemistries sen~itive to light, preferably a chopper (not shown) i8 disposed between light ~, ~ :.:

-21- 2~ 47 - 5 Source 686 and each aperture 666 to allow the light beam to strike a CM type element at any station only ~; when it is at endpoint.

Regarding evaporation cover 640, Figure 15, this cover is preferably grooved at 692 to provide clearance for liquid drops L on a PM type test element (element E that is sho~n), while at the same time providing for a sufficient length "i" to rear edge 692 that will ensure that non-grooved surface portion 693 seals over the lif~uid-bearing portion of a CM or ratetype test element, as is described and claimed in ourcommonly-owned Canadian Applicatio~ #8900611227 filed 09/13/89, entitled "Universal Evaporation Cover".

(Because no li~uid protrudes from such a CM or ratetype element, no clearance groove is needed). Most preferably, surface portion 693 and indeed all of cover 640 is manufactured from a non-porous material such as f polyethylene.

¦ Any suitable reflectometer 680 can be used.

J Highly useful is a diffraction grating reflectometer ' 25 680', Figure 17.

Such a reflectometer features a ~, conventional holographic diffraction grating 700, that uses a slit 702 in mask 704 to direct a line exposure of the light reflected from element E from the light source 706. (Fiber optics, not shown, can be sued to carry the light images.) Grating 700 in turn breaks ¦ the image into a continuous spectrum of wavelengths 1 through ~n~ which fall as a linear array on an image plane 710. A suitable array of imaging detectors 712 is used to detect the array of wavelengths, wherein each element of the detector 712 detects only one of the wavelengths ~i~ and the entire image within the I wavelength.

The signal from detector 712 is processed by an A/D converter 714 and sent via ..

'2 ''`' ', ~,' .. :.".. ', 3 -`~ ,2 '~, 201464 ~ -22computing means 716 to a suitable I/0 unit 718, ~uch as a CRT display.

Further details on dif'fraction grating reflectometers can be found in U.S.

Patent No. 4,544,271.

Not all test elements are read by reflectometer 680.

Specifically, PM type test elements require an electrometer 360, Figures 1 and 2.

Such an electrometer i~l conventional, and uses two electrical probes, not shown, that are pushed down into contact with a PM test element moved out of the incubator, arrow 362, onto support sur~ace 510, by a conventional pusher blade 363, Figure 2.

.. After a PM test element ii8 readi, it i8 moved to an aperture 364 in ~upport surface 510, where it falls out of the analyzer. A similar dump aperture 366 is provided for spent CM or rate test elements.

Those are pushed from the incubator, arrow 368, to aperture 366 by a conventional pusher blade 369.

The final station of' analyzer 20 to be encountered by a cartridge, during its residence in the analyzer, is the diæcharge portion of station j 300, Figures 13 and 16.

This portion f'eatures a door ;~ `! 326, 326' for each of the two paths 22 and 24, as is , especially 3hown in Figure 16.

Each such door opens and closes aperture 327, and is independently ~, operable by a motor 330, Figure 13.

Alternatively, `; they could be operated together even thou~h it is j unlikely both would be needed to discharge a spent : cartridge at the same time.

A useful construction of doors 326 and 326', , Figure 16, includ~es the following: Floor member 332 ., of housing 302 hangs a motor 330 from its underæur~ace, Fig. 13, that operates a pinion gear 336 off it~ drive shaft 338, Fig. 16.

Gear 336 in 35 turn operates a rack 340 that has a post 342 at one end.

Post 342 bears on a portion of door 326 or 326', alternatively, to push such door to operate ~ .

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2014647 : -23against tension spring 344 that bia~3eæ its respective door closed. Sensors 346 sense the position o~ door 326 or 3Z6', and sensor 348 senses a flag 349 or 349 in rack 340. In thi~3 fashion, a single motor can independently operate two independent doors for the discharge of cartridges.

The invention has been described in detail with particular re~erence to certain preferred embodiments thereof, but it will be understood that variations and modification~3 can be effected within the spirit and scope of the invention. ~.

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