MODULAR RESERVOIR SYSTEM

Abstract: A modular reservoir system which has a plurality of interchangeable fluid containment receptacle modules (14, 16, 18, 100), secured within the perimeter of a base frame (12). The frame (12) provides support and positioning for a user selectable configuration of modules (14, 16, 18, 100) to allow the user to perform a scientific experiment where a number of different reagents may be contained in close proximity for use by a pipettor or bulk dispenser. The modules are (14, 16, 18, 100) stand-alone components; or, they may be user selectably configured within the base frame (12) to enhance the usage of an automated fluid transporting and measuring work station. In an alternative embodiment, the invention discloses test tube support rack (80) and microtiter plate (102) modules for use in conjunction with the fluid reservoir modules (14, 16, 18, 100). In still another alternate embodiment, the invention discloses a pipette tip support rack module (122) for use in conjunction with the fluid reservoir modules (14, 16, 18, 100).

Description: MODULAR RESERVOIR SYSTEM Field of the Invention This invention relates to fluid reservoir containment systems and in particular to a modular fluid reservoir containment system for use in the performance of biological and chemical assays. Background of the Invention Biological and chemical research require the use of fluid containing reservoirs to conduct experimentation. Typically, these reservoirs contain biological specimen suspended or dissolved in a solvent; or, the reservoirs may be used for containing a reagent which reacts with the specimen previously aliquoted among a number of microtiter plate wells. Heretofore, chemical and biological research used fluid containment reservoirs of a fixed rectangular dimension which were essentially of elongated box construction. Alternatively, multiple reservoir containers have conventionally been designed which have a plurality of fixed compartmental partitions dividing the reservoir into segments for the storage of a plurality of reagents or other bulk used fluids. An example of such conventional laboratory fluid receptacles include the receptacles exhibited in a product catalog published 1983 by Flow Laboratories pharmacies of Helsinki, Finland; and a reagent reservoir sold by COSTAR of Cambridge, Massachusetts (Oct. 1, 1985 catalog). A typical application of the conventional reservoir has been for use in conjunction with a single tip or multichanneled pipettor. The pipettor may be manually operated or be a part of an automated laboratory work station. In any event, the conventional pipette reservoir is designed to accommodate a complete row of a multichannel pipette tool so that an experiment which requires the pipetting of a reagent simultaneously to a number of different microtiter plate wells can be accomplished through conventional pipetting techniques. Heretofore, fluid reservoir design has been limited to fixed volume arrangements which do not always accommodate the many types of reagent fluids in use to conduct experimental assays. Typically, conventional reservoirs have flat bottoms which does not assure that all the fluid contained within a reservoir will be aspirated by a pipettor system. Also, conventional reservoirs are not of uniform height to insure uniformity of liquid aspiration by a manual or automated pipettor. Conventional reservoirs have heretofore not been scaled to accommodate and assure optimum usage of an automated pipettor or fluid transport system. In the conventional art, U.S. Patent 4,154,795 discloses a microtest plate comprising means for enabling each microtitration well to be individually removable from the plate. Each well has side walls which engage compartments of a well holding tray, so the tray supports each removable well in an upright position. The wells may be joined by an interconnecting stem, so that the compartments of the tray are arranged in straight runs at right angles relative to one another. U. S. Patent 4,319,841 discloses a microcuvette unit having a plurality of cuvette components fitted into a frame for use in facilitating the identification of samples. Although this patent and the '795 patent disclose fluid containment systems which have removable components joined together by a frame structure, neither of these patents are directed to large volume fluid reservoir modular systems. An International Application, published under the Patent Cooperation Treaty, No. WO84/02775, published July 19, 1984, claiming priority on U.S. Application No. 830056, filed January 7, 1983, discloses a microcuvette set having several cuvettes arranged in matrix form along a frame to be handled as one unit. The matrix cuvette members snap into a frame which supports the unit. Heretofore, pipette tip racks, for holding disposable pipette tips, have conventionally been configured as a large rectangular surface, with conventional supporting walls along the perimeter of the rack, where the surface has a matrix of open container holes for holding the tips. A conventional rack allows adjacent tips to contact each other, with a resultant cross-contamination. This cross-contamination of one fresh pipette tip by an adjacent used tip may occur by physical contact of one tip to another, or by a phenomenon known as "aerosolizing" which can lead to contamination without direct contact. "Aerosolizing" contamination arises when a used tip is returned to the conventional rack and small quantities of residual fluid "fly" off the tip as part of the tip ejection process, especially in an automated system. The airborne fluid may then land onto clean tips leading to contamination. Additionally, conventional racks are generally not of sufficient strength to withstand flexing when vertically loaded on the top surface with sufficient force to fully seat pipette tips on a multiple tip pipettor. Should the top of the rack deflect under vertically directed loading conditions, not all of the pipette tips will seat at the same positional height along the pipettor nozzles. This problem is of greater significance in automated pipettor systems where the computer programming the automated pipetting relies on a uniform fit of tips on nozzles to carry out the desired fluid transfers. Conventional tip racks are not necessarily designed to be securely placed within a compartment of a movable table of an automated pipettor system. Conventional racks have a tendency to become loose when placed upon a moving support platform. What is needed is a pipettor tip rack which minimizes cross-contamination among adjacent tips and which has sufficient strength and stability for adaptation into an automated pipettor and fluid transportation system. Summary of the Invention A modular reservoir system is provided wherein a plurality of custom-made reservoirs are supported along a common perimeter of a base frame structure to create an adjustably configured reservoir assembly which may be user selectively targeted to the particular requirements of an experimental assay. In particular, each modular unit of the modular reservoir system are of the same heights and are symmetrical about their center lines. All the bottom surfaces are slanted in a central "vee" configuration to allow for maximum fluid aspiration. Due to their size and configuration, the modular reservoirs are easily adaptable for use in an automated analytical chemistry work station system for the performance of experimental assays. Each module has a pair of support walls which allow each component of the modular system to function as a self-supporting reservoir. The reservoirs may be made of a clear organic polymer or other transparent material and are of width sufficient to accommodate a standard eight channel pipettor. When a user desires to assemble a plurality of modular components into a uniform configuration, the components may be placed adjacent side to side and secured within a rectangular base frame which supports each modular unit through the use of a 'plurality of extended tabs which are capable of resting on the surface of the system frame. The frame also has a plurality of notches for receiving key shaped protrusions of the modular reservoir units such that each unit is keyed into a particular position along the perimeter of the reservoir system base frame. An article containing rack module, for holding elongated articles such as test tubes, is disclosed which has a base and a plurality of circular compartments depending from the base for receiving the test tubes. If the diameter of a particular test tube is substantially less than the inner diameter of the compartment, ' an insert member is provided for insertion into at least one of the compartments for supporting the test tube. The insert member is a form-fitting sleeve shaped to accommodate the outer diameter of the test tube, so that the narrow diameter tube may be supported with a compartment of said test tube rack. A multiple pipette tip containment rack is disclosed having a plurality of enclosed pipette tip containment cells matrixed across its flat rectangular surfaces. The tip containment cells depend downward from the surface and are connected by a network of ribbed members which reinforce the upper surface. In a preferred embodiment, the rack fills one compartment of a movable table of an automated system, having a foot ledge for supporting the rack. In a module embodiment, the rack is supported by extended tabs resting on the base frame. Brief Description of the Drawings Fig. 1 shows a perspective view of the modular reservoir system which is the subject of this invention. Fig. 2A shows a top view of a narrow single compartment reservoir. Fig. 2B shows an elevational cross-sectional view of the single compartment reservoir module, taken along 2B-2B of Fig. 2A. Fig. 2C shows a cross-sectional side view of single compartment reservoir taken along line 2C-2C of Fig. 2A. Fig. 3A shows a top view of a dual compartment reservoir module. Fig. 3B shows an elevational cross-sectional view of the dual compartment module of Fig. 3A, taken along line 3B-3B of Fig. 3A. Fig. 4A shows a top elevational view of a wide body fluid reservoir module with central baffles. Fig. 4B shows an elevational cross-sectional view of the fluid module shown in Fig. 4A, taken along line 4B-4B of Fig. 4A. Fig. 5 is a cross-sectional side view of a test tube or article holder, taken along line 5-5 of Fig. 6. Fig. 6 is a top view of an article holder or test tube supporting module. Fig. 7 is a cross sectional view of an article holder or test tube compartment insert taken cross sectionally along line 7-7 of Fig. 6. Fig. 8 is a perspective view on an alternative embodiment and arrangement of the modular reservoir system. Fig. 9A is a perspective view of a pipette tip supporting rack. Fig. 9B is a perspective view of the underside of a portion of Fig. 9A. Fig. 9C is a cross-sectional elevational view taken along line 9C—9C of Fig. 9D. Fig. 9D is a plan view of the underside of Fig. 9a, showing the preferred embodiment of ribbing members connecting the pipette tip containment cells. Fig. 10A is a cross-sectional view of an alternative embodiment of the tip rack of this invention taken along line 10A—10A of Fig. 10b. Fig. 10B shows an underside plan view of an alternative embodiment of the tip rack of this invention showing a diamond pattern reinforcement webbing connecting the pipette tip containment cells. Fig. 11 is a perspective view of another alternative arrangement of the modular reservoir system including a pipette tip rack module. Detailed Description of the Preferred Embodiment With reference to Fig. 1, a generally rectangular base frame 12, in the preferred embodiment, forms a perimeter around a plurality of modular fluid reservoir containers 14, 16, and 18. The base frame 12 is a rectangular box having its top removed to define an area slightly under the size of a standard 96 well microtiter plate. The outer diameter of the base frame 12 is dimensioned to be carried on a movable table of an automated work station, fitting within a designated compartment of the movable table. A ledge 17 is formed on top of the framebase 12, which circumscribes the entire border of the top of the base frame 12. This ledge 17 provides support for modules 14, 16, and 18. For purposes of illustration, three different types of reservoirs are shown in Fig. 1 surrounded by the base frame 12. A reservoir 14 is a single compartment fluid reservoir having a generally rectangular cross- sectional frame and a substantially vee-shaped bottom 20 portion. The reservoir 14 is capable of being used in a free-standing position apart from the base frame 12 and is supported by a pair of side panels 24 and 26. The reservoir 14 is symetrical along its entire length and is vee-shaped (see 20) in order to accommodate a manual or automatic pipettor (not shown) that is aspirating liquid from the reservoir 14. The vee-shaped bottom 20 assures that a pipettor will aspirate a maximum amount of fluid contained within the modular reservoir 14 up into the pipettor's disposable tip. Fluid receptacle reservoir 16 is shown to be a two compartment reservoir of greater width than reservoir 14 separated by partition wall 28. A generally double folded vee-shaped bottom 30 extends orthogonal to the partition wall 28 symetrically dividing the reservoir 16 along a line forming the vee 30 parallel to the supporting side panels 32 and 34. Baffles 31 are positioned along boundary lines 33 and 35 (Fig. 4A) to provide vertically extending blockage, reducing spillage when reservoir 16 is positioned on a movable table of an automated liquid transport system. The third reservoir 18 is shown to also have two compartments, but unlike reservoir 16, these compartments run along the length of the reservoir 18, parallel to side panels 38 and 40. A partition wall 36 separates reservoir 18 into two compartments. Each compartment has a symetrically arranged vee-shaped bottom and the entire reservoir 18 is supported by the supporting side panels 38 and 40. The twin vee-shaped bottoms 42 and 44 serve the same purpose as the vee-shaped bottoms 20 and 30, of reservoirs 14 and 16, by allowing a maximum amount of liquid to be pipetted during aspiration. The reservoirs as shown in Figs. 2A, 3A and 4A are supported respectively, by extended support tabs 52, 54, and 56 at one end and tabs 58, 60, and 62 at the other end, when the modules 14, 16, and 18 are seated within the frame 12; the tabs extend laterally outward from the body of the individual modular reservoir components and rest atop the lateral perimeter of the frame 12 (see Fig. 1). In addition to this extra support provided to the modular reservoirs by the extension tabs, locater keys 64, 66, 68 and 70 of Fig. 1 key into locater notches of the base frame 12, located along the frame ledge 17, to accommodate and guide the positioning of the modular reservoir units into frame 12. The top view of the reservoirs shown at Figs. 2A, 3A and 4A illustrate that the single compartment reservoir 14 has one symetrical vee-shaped groove 20 along its bottom, while the twin compartment reservoir 18 has twin vee-shaped grooves 42 and 44 along its bottom wall (See Figs. 2B, 3B, and 4B) . The wider body reservoir of Fig. 4A may have a single vee-shaped groove 30 which is folded again along lines 33 and 35 for maximum access to fluid contained within the receptacle. Figs. 2B, 3B and 4B provide a cross-sectional view of the profile of vee-grooves 20, 42, 44 and 30, respectively, and the additional folding along lines 33 and 35 (Fig. 4A) of the bottom of Fig. 4B. A partition wall 36 is shown dividing Figs. 3A and 3B into a twin compartment reservoir module. The supporting side panels, like 24 and 26, (of Fig. 2B) are slightly bowed inward at a 2° angle to allow the module reservoir 14 to securely slide into its berth at the base frame 12 (Fig. 1). Fig. 2C shows the notch locator keys 70 and 73 as integral with support tabs 58 and 52. The height 75 of the reservoir 14 along its central axis is uniform from tab 58 to tab 52, allowing liquid transfers to be made in an automated system. The distance between adjacent vees of the same size modules (like 18), when placed side to side in the frame 12, are the same. The fluid containment compartments of the fluid reservoir containers 14 and 18 are dimensioned to accommodate a standard eight channel pipettor, such that all eight channels of the pipettor may simultaneously aspirate and dispense fluid from any reservoir compartment. The containment compartments of reservoir 16 may each accommodate four tips of the eight channel pipettor. The modular fluid reservoir containers 14, 16, or 18 may be made from transparent or opaque organic polymers such as polystyrene or polypropylene. This design is intended to allow the containment reservoirs to be disposable and capable of lower cost manufacture. Fig. 5 shows an alternative modular component rack 80 which may serve as a rack for holding articles or test tubes. This component has a shallower base 81 than the fluid reservoir modules 14, 18, and 16. The rack 80 is capable, as shown in Fig. 8, of supporting a plurality of articles of elongated articles or test tubes, as 83 and 87. When it is necessary to support a test tube 87 which is of a diameter substantially smaller than the compartment 92, a concentric insert member 94 (Figs. 6, 7, and 8) made of resilient organic or polyethylene material may be placed in a particular containment compartment 96 to securely position narrow diameter article or test tube 87. The compartment 92 depends from the upper surface of the rack 80 and has a hole 97 through the bottom to allow optical density measurements to be undertaken. Fig. 7 shows a cross-sectional view of the concentric insert 94 wherein the hollow sleeve defined by said insert member 94 is configured to snuggly fit within the greater diameter of the compartment 96, yet accommodate the telescoping of a narrow diameter tube within its inner diameter 85. The insert member 94 has a shoulder 95 which hangs over the surface 99 (Fig. 8) of the rack 80 for improved support and ease of removal. The article container or test tube rack 80 may be made to encompass the entire cross-sectional area of frame 12 and is either free-standing or supportable within the frame 12 like the modular reservoir units. Alternatively, an article container or test tube rack 80 which is shown at Fig. 8 which is half the size of the area encompassed by frame 12, so that a reservoir 100 may be positioned within the frame 12. A microtiter plate module 102 may be structured for positioning between the reagent fluid reservoir module 10 or test tube rack 80. In this manner, a reservoir 100, microtiter plate 102, and a tube rack 80 may be carried by a common frame 12 on an automated laboratory workstation allowing a close transport of fluid sample or reagent. With reference to Fig. 9A, a multiple pipette supporting rack 104 is shown. A matrix formation of a plurality of enclosed pipette tip containment cells 106 covers the upper surface 108 of the pipette tip rack 104. A row of pipette tips 109 may be vertically supported, each tip in a separate enclosed compartment which prevents cross-containment between the pipette tips 109 positioned in separate tip-containment cells 106. A supporting foot ledge 110 is provided with a notch 111 which may be matably received in a compartment of a movable table on an automated pipettor system. In this manner, stable support may be provided to a plurality of pipette tips positioned on a rack 104 which is seated on a movable table of an automated pipettor system. Alternatively, the pipette tip supporting rack 104 may stand alone and be supported on top of a conventional laboratory work station. Turning to Fig. 9B, the underside of Fig. 9A is shown revealing the separate enclosed compartments formed by the pipette tip containment cells 106. A single pipette tip and its entire volume of fluid may be held within each pipette tip compartment 106 so that cross- contamination between adjacent pipette tips 109 is substantially avoided. With reference to Figs. 9C and 9D, it will be noted that in the preferred embodiment a plurality of ribbed reinforcement members 112 connect a plurality of tip-containment cells 106 to reinforce and strengthen the upper surface 108 of the pipette tip rack 104 and prevent flexing of the upper surface 108 when a multiple tip pipettor is pressed against the upper surface of the tip rack to secure tips. Fig. 9C shows a cutaway detailed view of how the ribbed matrix containing a plurality of ribbed reinforcement members 112 is formed. A cutaway view 114 through the center of a plurality of containment cells 106 shows that the ribbed members 112 are integral with the upper surface 108 and depend downward from the upper surface as much as one half the length of the containment cells. Fig. 9C shows that the containment cells 106 become an intersection for the meeting of a plurality of orthogonally positioned ribbed reinforcement members such as 112'. Fig. 9C also shows that the support foot ledge 110 is shaped in an L-shaped manner to provide maximum stability for the upper surface 108 of the pipette tip supporting rack 104. The ribbed reinforcement members 112 provide a great degree of strength, stiffness, and stability to the upper surface 108 of the pipette tip rack 104 heretofore not available in conventional pipette tip racks. The pipette tips 109 rest loosely within the containment wells 106; however, when one wishes to secure the pipette tips 109 to the end nozzles of a multiple tip pipettor mechanism, especially for an automated laboratory work station system, a great deal of force will be applied vertically downward in order to friction fit the pipette tips 109 to the ends of the multiple tip pipettor nozzles. This additional force, which was not present in manual pipettors, was strong enough to flex or bow the upper surface of a conventional pipette tip rack so that the pipette tips 109 did not necessarily uniformly seat along a plurality of nozzles on a multi-tip pipettor mechanism. Thus, in the preferred embodiment of this invention, the matrix of ribbed reinforcement members 112 integral with the upper surface 108 of the pipette tip rack 104 provide a degree of strength which assures that, when a multiple nozzle pipettor mechanism is used to retrieve a plurality of pipette tips 109, the pipette tips 109 will be uniformly seated at the nozzle ends of the pipettor mechanism. Figs. 10A and 10B show an alternative embodiment pipette tip rack 116 which has ribbed reinforcement members 118 joining at the containment cells 120 to form a diamond-shaped pattern. Fig. 10A shows the underside of the alternative -embodiment which stresses a diamond- shaped configuration of ribbed reinforcement members 118. The cross-sectional view of Fig. 10A shows the ribbed reinforcement members 118 extending at least two- thirds down the length of pipette tip containment cells 120. This greater length of the ribbed reinforcement members provides greater strength for the support of larger volume pipette tips. Fig. 11 shows a pipette tip supporting rack module 122 positioned along the rectangular base frame 12 and adjacent a microtiter module 102 and a bulk reservoir 18. The pipette tip supporting rack module has extending tabs 124 and 126 (one tab 126 partially shown) with integral notch locator keys such as 128, for positioning the pipette supporting rack module within the rectangular base frame 12 of the modular reservoir system. In this manner, an automated laboratory work station having a multiple pipettor mechanism may retrieve pipette tips from the pipette tip supporting rack module 122 by press- fitting pipette tips 130 onto the nozzles of the pipettor mechanism so that the disposable pipettor tips 130 may be used to transport fluid, for example, from modular reservoir 18 into microtiter plate module 102. Also, different size tips may be placed within the same frame 12, where modules which hold large volume tips may be placed adjacent modules which hold smaller capacity tips. It should be noted that the preferred embodiment is only illustrative of one form, with some variations, of a modular reservoir system. The scope of the invention is not necessarily limited to the preferred embodiment. Structural changes are possible, such as providing a rounded, parabola-shaped bottom channel along the central axis of each module; also, module 18 might have an orthogonal wall mid-length replacing wall 36 as shown in Fig. 1; also, the wall 28 of module 16 might be removed, leaving a module with baffles but no partition wall as in Fig. 4B; or, a single modular reservoir with no partition walls might fill the entire frame 12. These changes are intended to be within the scope of the invention. Consequently, the specific structural and functional details of this modular reservoir system are merely representative, yet they are deemed to afford the best embodiment for purposes of disclosure and for providing support for the claims which define the scope of the present invention.

Claims: What- is claimed is: 1. A fluid reservoir module, comprising: at least one fluid storage compartment, said compartment having a plurality of walls and a bottom surface; said bottom surface being symetrically disposed along at least one axis, and forming a channel along said axis; at least two of said walls being parallel to said axis, said at least two walls forming support legs to allow said reservoir module to be supported in a stable free-standing position. 2. The fluid reservoir module of claim 1, wherein the channel formed along at least one axis is an inclined vee-shaped channel. 3. The fluid reservoir module of claim 1, including a partition parallel to said at least two walls, and positioned in the same plane with said axis, said partition dividing said reservoir into at least a plurality of compartments. 4. The fluid reservoir module of claim 1, including a partition orthogonal- to said at least two walls, dividing said reservoir into at least a plurality of compartments. 5. The fluid reservoir of claim 1, including a plurality of vertical baffles to contain and control the flow of fluid resident in said reservoir fluid storage ■ compartment. 6. A modular reservoir fluid containment system, comprising: a base frame, said frame having a plurality of sides; a plurality of fluid reservoir modules; said frame providing support for and surrounding said modules; said modules being supported by at least two of said sides. 7. The modular reservoir system of claim 6, wherein the modules have laterally extended module tabs for support upon said base frame. 8. The modular reservoir system of claim 7, wherein at least two of said sides of said frame include locator notches for positioning said modules within said base frame. 9. The modular reservoir system of claim 8, wherein the modules include key means integral with said module tabs for fitting into said locator notches of said base frame, whereby said modules may be positioned within said base frame. 10. The modular reservoir fluid containment system of claim 6, wherein the modules are all of uniform height, said uniform height defined as a distance from the top of any of said modules to a deepest point along the bottom of said reservoirs. 11. The modular reservoir fluid containment system of claim 6, including a plurality of article-containing rack modules, each rack module having at least one compartment for supporting an elongated article. 12. The modular reservoir fluid containment system of claim 11, wherein the compartment for supporting an elongated article is integral with the surface of said rack module and is shaped to conform to the shape of said article. 13. An article containing rack module comprising: a base; a plurality of circular depending compartments on the surface of said base for receiving and supporting a plurality of elongated articles; a plurality of article supporting insert members, each of said insert members form fitting within each of said circular compartments and defining a sleeve telescoped within and concentric with each of said compartments, said insert member providing support for an article within a compartment where the cross-sectional diameter of the article is substantially less than the cross-sectional diameter of the compartment. 14. An article of manufacture for supporting elongated articles within an article supporting rack, said rack having a plurality of circular compartments, said article of manufacture comprising: an insert member for insertion into at least one of said circular compartments of said supporting rack, said insert member being a form fitting sleeve shaped to accommodate an outer diameter of an elongated article, said sleeve providing support for said article when the outer diameter of said article is substantially smaller than the diameter of one of said compartments. 15. The modular reservoir fluid containment system of claim 6 including: a microtiter plate module, having a plurality of wells, said microtiter plate module being structured for interchangeable placement in said base frame, so that a user may place one of said fluid reservoir modules adjacent said microtiter plate module within said frame. 16. The modular reservoir fluid containment system of claim 6, including: a multiple pipette tip containment rack module, said module further including: a rectangular rack having an upper surface; a plurality of enclosed pipette tip containment cells, each cell capable of containing a disposable pipettor tip and any fluid contained in said tip; a plurality of ribbed reinforcement members, each ribbed reinforcement member being integral with said upper surface of said rack and at least one of said members connecting at least any two containment cells; said module being supported at any two sides of said frame. 17. A pipette tip supporting rack comprising: a rectangular upper surface; a plurality of enclosed pipette tip containment cells; a plurality of ribbed reinforcement members, integral with and depending downward from said upper surface; at least a plurality of said ribbed reinforcement members interconnecting any two of said containment cells; and. means for supporting said upper surface. 18. The pipette tip supporting rack of claim 17, wherein said upper surface supporting means further comprises: side walls along the perimeter of said upper surface; each of at least two of said side walls having a support foot ledge, so that the rack provides stable support for said tips. 19. The pipette tip supporting rack of claim 17 wherein the ribbed reinforcement members intersect to form a matrix defining squares on the underside of said upper surface. 20. The pipette tip supporting rack of claim 17, wherein the ribbed reinforcement members form a plurality of diamond-shaped structures, across the underside of said rack, said diamond-shaped structures forming a rigid supporting matrix for the upper surface.

Inventors: KELLER BRENT WARD, MURRAY DONALD STORRS, PFOST DALE R, KELLER, BRENT, WARD, MURRAY, DONALD, STORRS, PFOST, DALE, R.
Applicants: BECKMAN INSTRUMENTS INC, BECKMAN INSTRUMENTS, INC.
Application year: 1987
Main classification: B01L3
IPC codes: B01L3, B01L9, B65D1, G01N1, G01N35