CA1097942A

CA1097942A - Disposable cuvette array

Info

Publication number: CA1097942A
Application number: CA280,129A
Authority: CA
Inventors: Frederick C. Bullock; Alvin Engelhardt; Thomas J. Cirincione; Joseph A. Williams
Original assignee: Alfa Wassermann Inc
Current assignee: Alfa Wassermann Inc
Priority date: 1976-06-09
Filing date: 1977-06-08
Publication date: 1981-03-24
Also published as: AU2600377A; AU510059B2; JPS5748975B2; IT1062253B; NL7706292A; CH615755A5; SE7706742L; DE2726219A1; GB1565561A; BE855559A; AT367908B; DE2726219C2; JPS5316968A; ATA411977A

Abstract

DISPOSABLE CUVETTE ARRAY

ABSTRACT OF THE DISCLOSURE
A cuvette array including a plurality of compartments circumferentially spaced about a central point, in which the array is disposable and formed from upper and lower discs of flexible thermoplastic material. The lower disc is formed with compartments, and the upper disc is bonded to the lower disc, closing off a portion of each of the compartments. A
locator ring is removably positioned upon the upper disc in one of a plurality of registered positions, and has portions thereof varying in light transmissivity that are used for signal processing purposes and to denote a primary one of the compartments. Preferably the locator ring is slotted on its outer periphery for signal processing purposes; alternatively, the assembly of upper and lower discs may terminate in an outer circumferential flange extending radially outwardly from the compartments and which is slotted.

Description

BACKGROUND A~D B~IEF
DESCRIPTION OF THE INVENTION

The present invention relates to cuvette arrays for centriEugal analyzers. The particular object of the invention is to provide a disposable cuvette array which is simple to manufacture and simple to useO
Cuvette arrays for centrifugal analyzers are known, which are typically formed from rigid materials. Such cuvette arrays are secured in place to the rotor assembly of an analyzer. The arrays are not disposable, and must be cleaned after each use. Further, they are of-ten held in place on the rotor assembly in cumbersome fashion, requiring time-consuming assembly and disassembly operations whenever it is desired to conduct tests with the analyzer.
In the present invention a cuvette array of flexible thermoplastic material is provided, which array is disposable.
The array is simple to manufacture and simple to use. Briefly, the array is ~ormed from upper and lower discs of flexible thermoplastic material. The lower disc is formed with compartments that are circumferentially spaced about a central point. The upper disc is bonded to the lower disc, and closes of~ at least a portion of each of the compartments. Each compartment may extend radially outwardly relative to the central point. A locator ring may be removably positioned upon the upper disc in one of a plurallty of registered positions. The locator ring may have portions thereof varying in light transmissivity that are used for signal processing purposes and to denote a primary one of the compartments.
Preferably, the locator ring may be slotted on its outer periphery for these signa] processing and compartment denoting purposes. Alternatively, the assembly of upper and lower discs may terminate in an outer circumferential flange

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`that extends radially outwardly from the compartmen-ts and which is slotted on lts periphery. The outer circumferential flange may be an outer circumferential part of the upper disc.
The lower disc of the cuvette assembly with its compartments may be easily produced by thermoforming of thermoplastic sheet material. The upper disc may also be produced from such sheet material, by simple stamping. The two discs may be bonded together by heat sealing along adjacent surfaces in contact with each other. The locator ring, a separate item, may be advantageously produced by injection molding.
The lower disc of the cuvette array may include a central hub portion with the compartments extending radially outwardly from the hub portion. The side walls of adjacent compartments would then be spaced apart from each other. The side walls may be joined together at least in part by a flat section of thermoplastic material. The lower disc may terminate in an outer circumferential flange and the upper disc may be bonded to the flange and the flat section of thermoplastic material. These two latter elements may be coplanar and the upper disc may be a flat annulus bonded to the flange and the flat section of the thermoplastic material.
The upper disc may include cut-away portions in registry with the compartments to provide for the introduction of fluids , into the compartments. Each compartment may have inner and outer compartments communicating with one another with a cut-away portion of the upper disc in registry with an individual pair of inner and outer compartments.
In use, the cuvette array may be easily positioned upon the rotor assembly of the centrifugal analyzer, wi-th the ~Q~7~
`:
locator ring being indexed thereon in appropriate position.
Although the cuvette array is of flexible thermoplasticmaterial, it may be held in place by rigid complementary parts of the rotor assembly. Such a cuvette array is thus easily fabricated and easily used, and is disposable so that it may be discarded after use. These are decided advantages over the rigid cuvette arrays currently in use which are not disposable, which are not simple to use, and which must be cleaned after each use.
The invention will be more completely understood by reference to the following detailed description.

BRIEE` DESCRIPTION OF THE DRAWING
Fig. 1 is a plan view of a cuvette array and locator ring embodyingthe invention.
Figs. 2 and 3 are sectional views taken along the sections 2-2 and 3-3 in Fig. 1.
Fig. 4 is a plan view of an alternative cuvette array and locator ring in accordance with the invention.

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Figs. 5 and 6 are sectional views taken along -the sections 5-5 and 6~6 in Fig. 4.
:
DETAII.ED DESCRIPTION

Referring to Figs. 1 to 3, a cuvette array 10 is shown~
The array is formed from flexible thermoplastic material, and includes a lower disc 12 and an upper disc 14. A separate locator ring 16 is also employed as a separate item, which is positioned upon the upper disc 14.
The lower disc 12 and the upper disc 14 are preferably formed from polyvinyl chlorideO This material is particularly useful, since it is inert to most fluids used for test purposes, it is of good light transmissivity for the proper transmission of light therethrou-Jh during a test, and is of sufficient strength to retain its confiyuration while undergoing forces cxeated during rotation of the cuvette assembly. Typically thermoplastic material in sheet form is utilized, which may be thermoformed into the configuration of the lower disc 12. As an example, the sheet material may be approximately 0.03 centimeter in thickness prior -to thermoforming, and is then stretched during the thermo-forminy of the lower disc 12 so that various parts thereo may be only 0.018 centimeter in thickness, while otherr non-stretched parts, remain at approximately 0.03 centimeter in thic~ness.
The relatively thinner parts of the lower disc 12 are typically found in the lower surface 12a thereof. It is to be understood that these dimensions are exemplary, and in no way limiting of the invention.
The lower disc 12 is formed into a plurality of compartments 18. These compartments 18 are circumferentially spaced about a central point 20, and extend outwardly in the radial direction.
The compartments 18 constitute a series of radially inner eompartments 18a and a series of radially outer compartments 18b.
Each radially inner compartment 18a communicates with an individual one of the radially outer compartments 18b, and is separated therefrom by dividing wall struc-ture 22, which includes an inclined wall 22a and a vertical wall 22b The lower disc 12 includes a central hub portion 24 which bounds the inner periphery of the compartments 18 by inclined wall structure 24a.

Each compartment 18 includes side walls 26 and 28. The adjacent side walls 26, ~8 of adiacent compartments 18 are spaced apart from each other, as at 30, and are joined together by flat 1, seetions of thermoplastic material 32 and 34. ~s shown in Fig.

3, these flat sections of thermoplastic material are at different ~
levels, joined together by an inelined portion 36, although this partieular eonfiguration is exemplary. The lower disc 12 terminates in an outer circumferential flange 38 which is coplanar with the flat section 34 of the lower disc structure which joins together the adjacent side walls 26, 28. The upper disc 14 is bonded to the lower disc 12 in the regions of these flat sections 34 and outer flange 38 of the lower disc 12. The bonding together of the upper disc 14 to the lower disc 12 is in the cross-hatched region 40 of Fig. 1. The bonding together of the two discs rnay he by radio frequency heat sealing, for example, and the sealing as shown isolates adjacent compartments 18 from each other, preventing undesirable crossover of fluid from one compartment to another.
The upper disc 14 is a flat annulus, which is typically produced by stamping from thermoplastic sheet material. As an example only, the thickness of thxt sheet material may be approxi-mately 0.05 centimeter. The upper disc 14 closes off at least a part of the compartments 18, depending upon the radial extent 33 of the upper disc. The upper disc 14 includes cut~away portions 14a thereof in registry with the compartments 18. In particular, the cut~away portions 14a extend radial].y over both compartment sections 18a and 18b for the purpose of introducing fluids into those compartments. To render -the cut-away portions 14a clearly visible, these portions of the upper disc may be rimmed with opaque material 42, such as by silk screening the upper disc.
It will be appreciated that the thermoplastic material constituting the upper disc 14 and lower disc 12 are typically transparent, and it may be difficult to visually percei~e the cut-away portions 14a.
The rimming of these opaque portions overcomes this problem.
To aid in positioning the upper disc 14 with respect to the lower disc 12 prior -to the bonding together of the two discs, nipples 44 may be employed forming a part of the lowër disc 12.
There are four of such nipples 44 shown in Fig. 1, although this number is representative, and they are equiangularly spaced about the periphery of the lower disc 12. The upper disc 14 includes corresponding holes 46 therein which re~ister with the nipples 44 and provide proper registry of the upper and lower discs, .
particularly so that the cut-away portions 14a are positioned over the center regions of the compartments 18 and so that the slots in the periphery of the upper disc 14, about to be described, are appropriately registered with respect to the compartments.
The upper disc 14 termlnates in an outer circumferential ~flange 14b which extends radially outwardly from the compartments 18 in the lower disc 12. That flange may be rendered opaque by the addition of opaque material 48 thereto, as by silk screening~
for example. The flange 14b is slotted, as at 50 and 52, to render it varying in light transmissivity in portions thereof used for signal processing purposesO It will be noted that the slots 50 are slightly wider in the circumferential direction and slightly longer in the radial direction than the slots 52. The slo-ts 50 a]ign with the central regions o~ the compartments 18, while the slots 52 align with the regions of the side walls 26, 28 of these compartments. As the cuvette assembly is rotated during use in a test in a centrifugal anaiyzer, the slots 50 and 52 interrupt a light beam, and this interruption is used for signal processing purposes.
The locator ring 16, described briefly above, is used to denote that one of the compartments 18 which is considered to be a primary compartment. The ring 16 may itself be made of thermo-plastic material, by injection molding, for example, and is in the shape of an annulus. The ring ]6 includes a series of holes 16a therein, certain ones of which engage the nipples 44 that extend upwardly rom the lower disc 12 through the upper disc 14.
To aid in locating ~he nipples 44, the upper disc 14 may be ringed with opaque material 54 about each nipple. The locator ring 16 is formed with numerals thereon. In the representative form shown in Fig. 1, the locator ring includes the numerals 2 through 20. Each numeral is adjacent a correspondiny opening 16b in the locator ring. The ring includes an arrow 56 formed thereon adjacent that one of the openings 16b constituting a pximary opening. Also adjacent that opening, in the periphery of the locator ring, is a single slot 16c. That slot 16c registers with one of the slots 50 in the periphery of the outer flanged portion 48 of the upper disc 14. In this fashion, one of the slots 50 is selected as a primary slot, and the corresponding compartmenk 18 is selected as the primary compartment~ The r~maining ones of the slots 5G are cover~d in part by the locator ring 16 so that one of the slots 50 selected as the primary slot is uncovered for its full radial extent by the slot 16c in the locator ring. It --7~

will be noted that the locator ring can be moved by the oper-ator of the centrifugal analyzer so that any one of the compart-ments 18 is designated as the primary compartment. In this fashion, the cuvette array may be used partially in a particular test, with only a few of the compar-tments 18 being utilized. For another, different test, the locator ring 16 is removed approp-riately to designate a new primary compartment, and previously unused compartments 18 are then used for the subsequent test.
By thus removably positioning the locator ring upon the upper disc 14 in any one of a plurality of registered positions, the cuvette array may be reused until all compartments 18 have been utilized in various tests~
The locator ring 16 is typically opa~ue. The openings 16b therein constitute windows which are in registry with the outer compartments 18b to permit the passage of light through the outer compartments for the testing of the fluids therein.
The locator ring 16 also includes tabs 58 about the inner periphery thereof which are used to retain the locator ring against the upper disc 14. In use, the centrifugal analyzer includes a part of the assembly which bears against the locator ring tabs 58 to retain the ring in place.
Figs. 4 to 6 show a slightly different version of cuvette array ancl locator disc with respect to the assembly of Figs. 1 to 3. In Figs. 4 to 6, the same re~erence numerals have been used to designate the same parts of the assembly of Figs. 1 to 3. The only change in the assembly of Figs. 4 to 6 is to remove the outer, slotted peripheral flange portion l~b of the upper disc 14 shown in Figs. 1 to 3 and to make it a part of the locator ring 16. The nipples 44 are sufficiently engaged by thesides of the holes 16a in the locator ring 16 so that the assembly of upper and lower discs 14 and 12 is held by the locator ring. Thus, as shown in Figs. 4 to 6, the locator ring 16 a~
lncludes an outer, peripheral por-tion 16d which is slotted, as at 50 and 52. The peripheral portion 16d may be of slightly less thickness than the remainder of the locator ring, as shown in Figs. 5 and 6, to provide for the close positioning of equipment in the centrifugal analyzer adjacent to the locator ring. In this case, the locator ring 16 includes only a single slot 50a of greater raclial extent than the remaining slots 50, used to designate the primary compartment 18.
By locating the slotted member on -the locator ring 16 rather than the upper disc 14, the fabrication of the upper disc is greatly simplified. ~xpensive silk screening of the outer periphery is no longer required, and the cost of the upper disc is greatly reduced. It is nonetheless still possible to retain the size and slotting of the upper disc 1~ as in Figs. 1 to 3, even though the silk screening is not present.
The locator ring 16 may also extend further inwardly in the radial direction than shown, in which case it may be slot-ted in registry with the cut-away portions 14a. In such a case, all sil]c screening on the upper disc 14 may be eliminated.
As noted above, the flexible array is formed of flexible thermoplastic material. The completed array may be flexed, and is retained in place on the rotor of the centrifugal analyzer by parts of the rotor which fit against the various outwardly exposed surfaces of the lower disc 12. The cuvette array is thus retained in place and will not undergo deformation cluring rotation of the rotor. Additionally, the side walls 26, 2~ add rigidity to the cuvette array, resisting radially directed forces which are imposed upon the array during rotation of the centri-fuge rotor.
It will be appreciated that the presently preferred embodi-ments of the invention disclosed and described above are subject to modification. Accordingly, the invention should be -taken to be defined by the following claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A cuvette array that includes a plurality of compartments circumferentially spaced about a central point, characterized in that the array is disposable and is formed from upper and lower discs of flexible thermoplastic material, said lower disc is formed with said compartments, and said upper disc is bonded to said lower disc and closes off at least a portion of each of said compartments.

2. A cuvette array according to claim 1, in which said lower disc includes a central hub portion, said compartments extend radially outwardly from said hub portion, and the side walls of adjacent compartments are spaced apart from each other

3. A cuvette array according to claim 2, in which each pair of adjacent side walls of said lower disc compartments are joined together at least in part by a flat section of thermoplastic material.

4. A cuvette array according to claim 3, in which said lower disc terminates in an outer circumferential flange, and said upper disc is bonded to said flat section and said flange of said lower disc.

5. A cuvette array according to claim 4, in which said outer circumferential flange and said flat section of said lower disc are coplanar, and said upper disc is a flat annulus bonded to said outer circumferential flange and said flat section of said lower disc.

6. A cuvette array according to claim 1, in which said upper disc includes cut-away portions thereof in registry with said compartments to provide for the introduction of fluids into said compartments.

7. A cuvette array according to claim 6, in which said compartments of said lower disc constitute a series of radially inner and a series of radially outer compartments circumferentially spaced about said central point, each radially inner compartment communicates with an individual one of said radially outer compartments, and each of said cut-away portions of said upper disc is in registry with an individual pair of communicating radially inner and outer compartments.

8. A cuvette array according to claim 1, in which the assembly of said upper and lower discs terminates in an outer circumferential flange extending radially outwardly from said compartments and of a light transmissivity varying in portions thereof and used for signal processing purposes.

9. A cuvette array according to claim 8, in which said outer circumferential flange is an outer circumferential part of said upper disc.

10. A cuvette array according to claim 1, in combination with a locator ring removably positioned upon said upper disc in one of a plurality of registered positions.

11. A cuvette array according to claim 10, in which said locator ring has portions thereof varying in light transmissivity that are used for signal processing purposes and to denote a primary one of said compartments.

12. A cuvette array according to claim 11, in which said locator ring is slotted on its outer periphery, said slots are in registry with said compartments, and one of said slots is of unique configuration to denote said primary one of said compartments.

13. A cuvette array according to claim 11, in which said locator ring includes tabs on the inner periphery thereof used to retain said locator ring against said upper disc.

14. A cuvette array according to claim 11, in which said upper disc includes nipples extending therethrough from said lower disc and removably engaged by said locator ring in one of a plurality of positions for providing variable positioning of said locator ring upon said upper disc.

15. A cuvette array according to claim 11, in which said upper and lower discs are of substantially the same diameter, and said locator ring is of greater diameter.

16. A cuvette array according to claim 1, wherein each said compartment extends radially outwardly relative to said central point.

17. A cuvette array according to claim 1 or 16, adapted for installation on the rotor of a centrifugal analyzer, wherein said compartments are adapted to hold samples for in situ centrifugal analysis.