NZ232064A - Fluid containing cell: flexible pressure wall nests within delivery wall when cell is empty - Google Patents

Description

232064 Priority Date(s): .. 2&iSv.lST?.- Publication Date: ..#$1.. P.O. Journal. No: Under the provisions of Regu-joiion 23 (1) the Specification has been anfe-dated to. 19 ££~ initials Patents Form No. 5 PATENTS ACT 1953 COMPLKTK SPECIFICATION FLUID INJECTION SYSTEM FLUID CONTAINERS AND FLUID PACKAGING METHODS Xf/We SURGIKOS, INC. a corporation organised undfer the laws of the State of New Jersey, United States of America, of 2500 Arbrook Boulevard, Arlington, Texas 76010, United States of America do hereby declare the invention for which i/we pray that a Patent may be granted to ihc/us. and the method by which it is to be performed, to be particularly dcscribcd in and by the following statement: Dated (followed by page la) 232064 The present invention relates to fluid containers or cells for use in a system for injecting or dispensing controlled volumes of fluid, the system being particularly useful for automated injections of very small amounts of fluid into a sterilizing chamber for items such as medical instruments- Background of the Invention New Zealand patent specification No 216563 discloses a sterilization system in vhich an agent such as hydrogen peroxide Is introduced Into an evacuated sterilizing chamber wherein It Is vaporized and allowed to disperse onto the items to be sterilized. After a desired period of time, electrical energy is then applied in the chamber to Ionize the gas to form a plasma at a power level sufficient to achieve sterilization. These steps can be performed in different chambers.

The system is proving to be very effective, and also has a number of advantages over other known systems. Consequently, the system is being commercialized and a need exists for apparatus providing the proper quantity of the desired fluid In a safe, convenient and practical manner. Also, an injection system must perform its function accurately and reliably without providing a leak path for the introduction of unwanted air or other naterial to the sterilizing chamber. In addition to preventing leaks, the accuracy requirement includes the need for minimizing the volume of fluid that remains in the system between injections.

When the system is used with sterilizing apparatus in a medical environment such as in a hospital, it is likely to be operated on a repeated basis throughout the day by personnel having a widely varying range of understanding of the apparatus employed. Hence, it is important that the system be simple to operate, be fully automated and m 232064 have adequate safeguards with respect to human error in view of the critical nature of sterilization o_f medical items. Minimizing the chance of human error is thus important. Also, the apparatus must have adequate reliability for heavy usage of the apparatus over an extended period of time.

Prior fluid injection systems in sterilizing apparatus do not provide the desired features. In one known system, ethylene oxide gas is sealed under its own pressure in a TO container and then dispensed as needed. This approach is not practical with a liquid delivery system in that a gaseous propellent contained in the liquid is not acceptable in the sterilizing process. Also, delivery pressure decays during the delivery process, which can j5 result in an undelivered dead volume, and degradation in the quality of atomization of the fluid as it enters the chamber.

Thus, a need exists for an improved system.

Brief S""»"ary of the Invention 20 The entire improved system is disclosed herein, however, basically only the fluid containers or cells and /S method of packaging fluid are claimed. Briefly stated, the Invention claimed comprises a fluid delivery cassette having relatively rigid vails defining a compartment and a 25 fluid containing cell sealed within the compartment. The compartment is formed with a hole in a delivery vail through which fluid may be ducted out of the cell, and an aperture in a pressure vail of the compartment through vhich pressure may be applied against a movable wall of the cell to force fluid out of the cell.

Preferably the cell movable wall is flexible and is formed with a recess which conforms to the shape of the delivery vail so that the flexible vail may be inverted against the delivery vail to ensure that substantially all 35 of the fluid is forced out of the cell, thus providing - >■*'-"■ ;232064 ;-3- ;o desired accuracy in the process in which the fluid is used. - ;Preferably the cassette includes walls forming a plurality of compartments and there is a cell positioned 5 in each compartment. Conveniently, these cells are formed from two sheets of plastic having mating recesses therein, and the peripheries of the recesses are bonded together to form a series of compartments held together as a single cell pack. This cell pack is captured between mating 10 portions of the cassette so that each cell is securely gripped and each compartment is sealed from the others. The cassette preferably is in the form of a generally flat, elongated, rectangular configuration such that it can be easily handled, and inserted into a pumping 15 mechanism. Advantageously, the cost of the cassette is such that, it is practical to dispose of it when all cells have been used. ;The cassette is provided with various indicating features to perform a number of different functions. An 20 indicator label initially extends over the opening in each compartment. If any of the cells leak, the indicator label vill change its appearance so that the user vill observe this and thus discard the cassette. There is also a code that is read by means in the pumping mechanism, 25 identifying the material in the cells and indicating the date of packaging. The primping mechanism will not function unless the machine has been programmed for the proper material and the cell material is fresh enough. Indicia on the side of the cassette such as a hole vill be 30 observed by a suitable sensor to control means for properly positioning the cassette and moving the cassette wiLhin the pumping apparatus. When a cell Is pierced during its emptying operation, a separate indicator foil in an aperture adjacent the cassette is also pierced, and 35 the presence or absence of the foil in a particular opening indicates whether an associated cell is still ;232064 ;-4- ;intact, and thus the foil helps position the cassette for successive fluid injecting operations. ;In accordance with the method of the invention, fluid to be dispensed is .packaged by forming a closed cell with a known quantity of fluid sealed therein; positioning the cell in a cassette having a compartment formed therein for enclosing the cell; forming a hole in a wall of ; the compartment through which fluid from the cell may be dispensed and forming an aperture in a wall of the compartment to which pressure may be applied to force fluid up out of the cell. ;The cell pack itself may be conveniently formed by forming a plurality, of shallow recesses in one flexible sheet; forming mating, opposing shallow recesses in another flexible sheet; and bonding the sheets together around the peripheries of the mating recesses thereby forming a plurality of interconnected, shallow, sealed cells. Further, the method includes capturing such sheets between . the mating sections of a cassette with the periphery of each cell being clamped between cassette sections. ;Other features of the fluid handling system disclosed herein are claimed in New Zealand Patent Specifications 224,539, 224540, 224541, and 224542. ;Brief Description of the Drawings ;Fig. 1 is a perspective, somewhat schematic view of sterilizing apparatus illustrating the system of the invention. ;Fig. 2 is a top perspective view of. ♦■.he cassette or cartridge of Fig. 1 containing the fluid to be dispensed. ;Fig. 3 is a bottom perspective view of the cassette of Fig. 2. ;Fig. 4 is a top perspective view of a pack of fluid cells contained within the cassette of Figs- 2 and 3. ;Fig 5. is a top plan view of the forward end of the cell pack of Fig. 4. ;232 0 64 ;-5- ;Fig. 6 is a cross-sectional view on the line 6-6 of Fig. 5. ;Fig. 7 is a cross-sectional view of the cassette on line 7-7 of Fig. 2. ;Fig. 7a is a fragmentary perspective view of an alternative construction for a portion of a cell pack. ;Fig. 8 is a top, perspective, partially cutaway view of the cassette positioning and compressing mechanism of Fig. 1. ;Fig. 9 is an exploded perspective view of the injector valve assembly of the invention. ;Fig. 10 is an exploded perspective view of the cell piercing and floating seal mechanism which is a portion of the assembly of Fig. 9. ;Fig. 11 is an enlarged perspective view of the Injector valve assembly. ;Fig. 12 is a cross-sectional view of the injector valve assembly on line 12-12 of Fig. 11, together with a cross-sectional view of the air delivery system for compressing a fluid cell in the cassette. ;Figs. 13, 14 and 15 are schematic views of the fluid injection system in operation. ;Detailed Description of the Preferred Embodiment ;Referring to Fig. 1, there is schematically illustrated a cylindrical chamber 10 having a door 12 on one end. The chamber is connected to a suitable vacuum source by way of a conduit 14. The chamber is adapted to receive items to be sterilized, such as surgical instruments, in accordance with a method outlined in the above-referenced patent, wherein a liquid such as hydrogen peroxide is introduced into the chamber. For delivering such fluid, in accordance with the present invention, there is provided a fluid injection system 16 positioned adjacent to the chamber 10. ;The system includes a cassette or cartridge 18 containing the fluid to be Injected, a cassette receiving, ;232064 ;-6- ;positionlng and clamping mechanism 20, and a fluid injector valve assembly 22 mounted on and interconnected with the chamber. The fluid injector system 16 can be thought of as a pump in which the cassette 18 is inserted into the cassette receiving mechanism 20 and doses of the media contained in the cassette are automatically injected into the chamber during automated sterilizing cycles. Cassette ;The cassette 18 is in the form of a flat, rectangular rigid structure preferably made of plastic or other suitable material. The form of the cassette illustrated Includes an upper housing section 24 which mates with the lover section 26 to capture and enclose a cell strip assembly 28 or cell pack. The sections are held together by fasteners or other suitable means. The pack assembly has a rectangular shape, with slightly smaller dimensions than that of sections 24 and 26 such that the pack fits within the confines of the outer sections, as may be seen from Fig. 7. ;The cell pack Includes a plurality of fluid cells 30 arranged in the form of two rows of spaced cells with the cells of one row being offset in a lengthwise direction from the cells of the adjacent row and partially positioned between the cells of the adjacent row. Such an arrangement provides ten cells in the example shown in a compact space. When considering the sequence of the cells in the longitudinal direction of the assembly, this places the first cell in one row and the second cell in the other row, etc. ;As seen from Figs. 5 and 6, each cell is formed by a pair of flexible vails Including a delivery vail or side 34 and a pressure vail or side 32. As seen from Fig. 5, these walls have a spherical exterior and are bonded together around their periphery, forming a joint or seam 36. These walls 32 and 34 are preferably each formed or molded In a plastic sheet on a spherical radius. The ;232064 ;-7- ;radius 35 of the pressure side 32 is slightly smaller than the radius 33 of the delivery side 34 in an amount equal to the formed film thickness so that the pressure side vill nest perfectly into the delivery side vhen the cell is emptied. This contributes to the accuracy of the amount of fluid delivered and avoids dead volume. The cells are filled vith liquid 31 of a precisely known volume- Advantageously, the liquid is unpressurized in the cell such that volumetric accuracy is simplified, as are leakage problems. Preferably, cell filling is done in conjunction vith the operation of bonding the peripheries of the layers of the cell. In the example of the sterilizing method referred to in the above-referenced patent, the liquid sealed vithin the cell is hydrogen peroxide but, of course, other materials can be used; and the cassette and cell structure is useful for delivering fluid in connection vith operations other than in connection vith sterilizing apparatus. ;The lower cassette section 26 is formed vith a plurality of vails 38 forming a plurality of internally facing spherical recesses 39 matching the shape of the delivery side 34 of a cell 30. The cassette upper section 24 is formed vith a plurality of circular vails 40 vhich, in cooperation vith the vails 38, form a plurality of circular compartments 42 each of vhich confines a cell 30. The lover section has a flat annular vail stir face 44 surrounding the recess 39 vhich vith the lover circular edge of the vail 40 securely holds the cell bonded joint 36 to seal the compartment 42 in that area. The recess 39 is likevise sealed in this manner. The pliability of the plastic material forming the joint 36 assists in forming a seal. If the material forming the cell pack is not adequately pliable or resilient, a suitable gasket may be added. ;As may be seen, the pressure side of 32 of a cell is spaced from the flat vail of the upper housing section 24 ;232064 ;-8- ;so that a space or pressure cavity is formed thereby. The pressure side of each compartment 42 i6 formed vith an aperture 46 that interconnects the compartment 42 vith the exterior of the cassette. Ten of these apertures 46 may be seen in Fig. 2. Each aperture 46 is located near the periphery of its compartment 42 on the side of the compartment that is adjacent to the other rov of cells and compartments. This arrangement creates a single rov of apertures 46. ;The rov of apertures 46 is covered by an indicator 8trip 47 having a lover layer 47a vhich engages the cassette surface and is exposed on one side to the compartment 42. This lover layer 47a is treated chemically such that if it is exposed to hydrogen peroxide, it vill change color, thus indicating that the cell 30 in that compartment is leaking. Of course, if material other than hydrogen peroxide is confined in the cell, the layer 47a vill be treated vith an appropriate material vhich vill indicate the presence of that fluid. An upper layer 47b is a film of plastic to protect the indicator layer 47a from material other than the fluid in the cell and to trap any fluid that has escaped. ;The lover cassette section 26 is formed vith a hole 49 vhich is centrally positioned in the recess 39 and vith respect to the cell 30 in the compartment 42. This creates tvo rows of holes 49 vhich may be seen in Fig. 3. In addition, there is formed a socket 50 in the lover housing section 26, spaced laterally from each hole 49, thus positioning such socket betveen a pair of compartments in the adjacent rov. Since a similar socket 50 is laterally aligned vith the hole in each socket, this creates tvo rovs of sockets 50, each aligned vith a rov of holes 49, as may be seen from Fig. 3. These sockets extend inwardly about half vay into the cassette, the sccket upper surface, as viewed in Fig. 7, being approximately flush with the annular wall 44 surrounding each compartment. ;232064 ;-9- ;Both cassette sections are formed with a plurality of aligned openings 52 arranged in a row thq£ extends parallel to the longitudinal edge of the cassette, spaced inwardly a short distance from the right edge, as viewed in Figs. 2 and 7. Also formed in this same row is a slot 54 that extends through both sections. The slot is at the entry end of the cassette at the end of the row of openings 52. A transparent edge portion 56 of the cell pack intersects the openings 52 and the slot 54. More specifically, the upper cassette section 24 is formed with a series of projecting wall portions 58 vhich define the portions of the slot 54 and openings 52 vhich are in the upper section. These projections 58 engage the strip portion 56 and capture it against the inner surface of the cassette lover section 24. ;A layer of foil 62 is positioned on the plastic sheet 56 in that location and may be seen through transparent plastic. The foil is perforated as an indicator when an associated cell 30 is used, as will be described below. ;The cassette is further formed vith a plurality of spaced grooves 64 on one edge of the upper surface of the cassette upper Beet ion 24, the grooves being transversely aligned vith the openings 52 and extending from the openings to the edge of the cassette. The spacing betveen the grooves and betveen the openings is equal to the spacing betveen the apertures 46 and holes 49 in the cassettes. There is a groove 64 transversely .aligned vith each compartment 42. Hovever, it is not necessary that they be aligned; only that one groove is associated vith each compartment, and that an offset (if any) is constant. In addition, there is a groove on the entry end of the cassette vhich is spaced forvardly from the first compartment, and three grooves on the trailing end of the cassette vhich extend beyond the last compartment 42. In the particular system disclosed, the first two and the last one groove are included for aesthetic reasons only. ;232064 ;-10- ;Also positioned on the surface of the cell strip portion 56 is a bar code 66 located at the entry end of the cassette. This bar code vhich identifies and dates the cell pack is aligned vith the slot 54 so that the bar code can be read through the slot. The date is preferably the date the cells vere filled vith fluid or the safe use expiration date of the fluid. ;An indicator strip or label 67 is attached Co the lover surface of the cassette and covers the holes 49, as veil as the sockets 50, the openings 52 and a portion of the slot 54. A window 69 in the label 67 permits partial viewing of the bar code 66. A strip layer 67a indicates the existence of cell leakage, and a plastic layer 67b seals the area and protects the indicator layer. ;As seen from Fig. 3, there is provided a sensing hole 68 on the edge of the cassette near the trailing end of the cassette. This hole is used as a stop or indicator in connection vith the positioning of the cassette in the dispensing mechanism, as to be subsequently described. ;The cassette 18 provides a convenient package for presenting measured quantities of the fluid to be dispensed. Although the structure uniquely Includes many features, it is Inexpensive in mass production, and thus is practical as a disposable item. In addition to providing a convenient vehicle for the fluid to be dispensed, it protects operating personnel from being exposed to fluid in the cassette. Likevise, it presents a safe and protected storage means for the fluid so that it is not contaminated. ;Cassette Receiving and Clamping Mechanism ;The mechanism for receiving a cassette 18 includes an outer hollov frame 70 vhich is mounted on the sterilizing chamber 10, preferably by being positioned on the injector valve assembly 22, as seen in Fig. 1. Positioned vithin this frame 70 is a platen 72 vhich 16 adapted to receive a cassette 18, as seen in Figs. 1 and 8. The platen is ;232064 ;-11- ;forced upward by suitable springs 74. A clamping plate 76 is pivoted to the rear portion of the frame JO and is forced upward by suitable springs 78 so as to create a space vith the platen 72 for receiving the cassette 18. A clamp saddle-member 80 straddles a cassette 18 and is pivotally mounted by pins 81 carried on arms 76a depending from the clamping plate. ;Positioned on the top side of the clamp plate 76 is a roller 82 vhich supports the forward end 84a of an elongated cam 84. The cam further includes a central section 84b vhich slopes dovnvardly and rearvardly, and a trailing horizontally extending section 84c vhich is at a lover level than the forvard section 84a. The cam is mounted on an actuator rod 85 extending from an actuator housing 86 vhich in turn is supported on a fixed structure such as the frame 70 by suitable means (not shown). The actuator is in turn connected to a source of pressurized fluid by a conduit 87, as seen in Fig. 1 but, of course, could be energized by other means, such as electric. ;On the saddle clamp 80 is a clamp assembly 83 for pressurizing or forcing fluid 31 out of a cell 30. The clamp assembly 83 includes a generally cylindrically shaped clamp 88 vhich extends through the clamp saddle 80 and includes a flat lover surface adapted to engage the upper surface of a cassette 18. An annular spring element 89 captured In a groove in the clamp 88 extends outvardly and dovnvardly to react against the top surface of the clamp saddle 80 to hold the clamp 88 in position on the saddle 80. An O-ring 90 positioned vithin a shallov recess in the face of the clamp 88 extends slightly belov the face. A tubular piercing needle 91 is mounted vithin a passage 92 in the clamp 88, vith the piercing tip of the needle extending slightly belov the lover surface of the clamp and the O-ring 90. The' passage 92 in the housing is in turn connected by a suitable flexible conduit 93 to a source of pressurized air. ;232064 ;-12- ;To position the cassette 18, there is a provided a drive roller 94 rotatably mounted on the frame .70, which frictionally engages the upper surface of the cassette, the roller being driven by a motor 95 also mounted on the frame 70. For stopping the cassette in proper position vith respect to a cell 30, there is provided a spring loaded pawl 96 vhich cooperates vith the grooves 64 on the upper surface of the cassette. The pawl i6 movable by a solenoid 97 mounted on the frame 70. Also provided is a sensor or detector 98 for reading the bar code 66 in the cassette positioned below a hole (not shown) in the platen 72 to be aligned vith the openings 52 and the slot 54 vhen a cassette is inserted into the mechanism 20. Also positioned on the frame 70 is a detector 99 (not shown in detail) located to observe the edge of the cassette as it moves vithin the cassette positioning mechanism. A schematically indicated microprocessor 21 connected to the detectors controls the operation of the mechanism 20. Injector Valve Assembly ;Turning now to Figs. 9, 10, 11 and 12, it may be seen that the injector valve assembly 22 includes a mounting body 100 which is welded or otherwise suitably secured to a vail 11 of the chamber 10. The injector body 100 has a cylindrical interior in vhich is positioned mating sections 102 and 104 forming a valve body or housing. These sections are clamped together by a spanner nut 106 or other suitable means vhich threads into the interior of the body 100, vith a vasher 108 positioned betveen the nut 106 and an outvardly extending flange on the upper valve housing section 102. ;The primary housing section 104 includes a centrally located, upvardly extending annular valve seat 110 surrounding the entry to an elongated valve outlet passage 111 in the primary section that is covered or closed by a large, flat flexible diaphragm 112 vhich forms a movable, pressure-responsive valve element for controlling flow ;232064 ;-13- ;through the valve. The diaphragm 112 fits within a circular, flat recess 114 formed in the primary housing section 104. The recess 114 is flush with the valve seat 110. Formed in the central portion of the recess 114 is a smaller diameter shallow annular recess 116 surrounding the annular valve seat 110 and forming a portion of an inlet passage to the valve seat 110. The radial dimensions of the recess 116 is quite large relative to its depth such that a large valve opening force is generated with negligible fluid volume. For example, in one form of the invention the recess 116 depth is about .007 inch and the recess diameter is about .9 inch creating a volume of about .004 in3. ;Also formed in the lower housing section 104 are a pair of radially extending, circumferenttally spaced, shallow passages 120 vhich open on their radially inner ends to the inlet recess 116. The radially outer ends of these passages are aligned with openings 113 formed in the flexible diaphragm 112 and aligned with small diameter passages 122 extending in an axial direction through the upper valve housing section 102 radially outvardly from the central space 131. A pair of positioning pins 124, shovn in Fig. 9 (only one of vhich is shorn in Fig. 12), extend through radially outer portions of the valve housing sections 102 and 104, the outer periphery of the diaphragm 112 and into a socket in the valve assembly body 100. These pins 124 orient the diaphragm 112 in the upper housing section 102 so that the holes in the diaphragm and the passages in the upper housing section are aligned vith the radially outer ends of the passages 120. They also align the entire Injector body assembly to the cassette receiving mechanism. ;An outer O-ring 126, positioned vithin a groove in the upper housing section 102, seals the valve inlet passage radially outvardly from the passage 122. Correspondingly, an inner O-ring 128 prevents fluid flow betveen the upper ;232064 ;-14- ;side of the diaphragm 112 and the upper housing section 102. _ ;Positioned on top of the diaphragm 112 is a movable piston 130 located within a suitably formed, centrally located space 131 in the upper housing section 102 which is open to ambient pressure. A lower head portion 130a of the piston 130 engages the top side of the diaphragm 112 opposite from the valve seat 110. A compression spring 132 surrounds an upper cylindrical portion of the piston 130 and reacts against a shoulder 130c to force the piston 130 into valve closing position against the diaphragm 112 and the valve seat 110. The other end of the spring 132 reacts against a retainer plate 136 which is attached by suitable fasteners 138 to the upper end of the upper valve housing section 102. ;Positioned on the lower end of the lower valve housing section 104 is an atomizing nozzle 140 clamped against a filter 142 and an O-ring 144 by means of a surrounding sleeve nut 146. An atomizing finger 148 secured to the nozzle 140 is aligned vith an opening through the nozzle and vith the valve outlet passage 111 to facilitate the atomizing of fluid ejecting from the outlet. ;Cell Piercing/Floating Seal Assembly ;Still referring to Figs. 9-12, the injector valve assembly further includes a cell opener assembly or a cell piercing and floating seal assembly 150. The assembly 150 vhich forms a fluid coupler includes a conduit in the form of a tubular needle 152. The needle is secured to a surrounding needle support member 154 positioned vithin a socket 156 formed in the upper surface of the upper valve housing section 102. The socket is adjacent to but spaced radially outvardly from the central space 131. The lower portion of the needle fits closely vithin the inlet passage 122, vhile the sharp upper end of the needle extends upvardly in position to pierce a fluid cell 30. A resilient tubular seal element 158 having an axial bore ;232064 ;-15- ;thereln surrounds the upper portion of the needle 152. A tubular follower 160, made of material more rigid than the seal 158, engages the lower portion of the seal 158. A tubular sleeve or guide 162 surrounds the seal 158 and extends through an opening 161 in the retainer 136. The guide 162 is provided with an outwardly extending flange which engages the lower surface of the plate 136, and the lower surface of this flange engages an outwardly extending flange 158a on the lower end of the seal 158. ;A compression spring 164 extends between a flange 160a on the follower 160 and an outwardly extending flange on the lower end of the needle support 154. This spring biases the follower 160, the seal 158 and the guide 162 upwardly against the retainer plate 136. The spring also biases a small O-ring 166 into a groove in the housing section 102 surrounding the needle 152 so as to prevent fluid flow between the passage 122 and the socket 156. ;The upper end of the seal 158 includes an upwardly extending annular face portion 158b vhich engages the lower surface of a cassette 18 to form a seal therewith. The bore vithin the seal 158 includes an invardly extending seal portion 158c on its lover end which resiliently engages the exterior of the needle 152 to form a seal at that location. The central protuberance on the lover end of the seal 158 surrounding the portion 158c has a conical shape that fits vithin a mating conical recess in the upper surface of the follower 160. These mating surfaces, together vith the force of spring 164, bias the seal portion 158c into engagement vith the needle to form a good sliding seal. ;As seen from Figs. 9 and 11, there are a pair of cell piercing assemblies 150 circumferentially spaced from each other on the housing section 102. ;Operation ;Vhen the system of the invention is to be employed, articles to be sterilized are placed vithin the chamber 10 ;232064 ;-16- ;through the opening covered by the door 12, after which the door is securely closed. A cassette 18 containing a fresh cell pack 28 is selected to be manually inserted into the injector mechanism 20. Before the cassette is inserted, the indicator strips 47 and 67 are observed to see whether they indicate that any of the cells are leaking hydrogen peroxide. If a leak exists, the indicator strip on the leak side will have a color indicating such condition, and the cassette should not be used. If the cassette is in proper condition, the strip 67 is removed by way of a suitable pull tab 67c and the cassette is inserted. ;As the cassette is being inserted, a number of events occur. The sensor 99 aligned with the edge of the cassette detects the presence of the cassette. A signal from the control 21 starts the motor 95 to rotate the drive roller 94 in a direction to move the cassette into the mechanism. As the cassette is driven in, the bar code 66 is read by the sensor 98 by way of the slot 54 and the information transmitted to the control 21. If the cassette is inserted backwards or inverted, the absence of bar code information will cause the mechanism not to accept the cassette. If the cassette is properly oriented but the strip 67 has not been removed, only a portion of the code is seen through the window 69 in the strip 67, causing the solenoid 97 to release the pawl 96 and causing the motor 95 to reverse direction to eject the cassette. ;The bar code indicates the nature of the fluid in the cassette, vhich is necessary since cassettes containing different sterilants or sterilants of different volumes may be utilized vith the apparatus of the invention. Also, the bar code vill tell the date on vhich the sterilant - pack 28 has been filled. If vrong material is used or the date is beyond ar acceptable shelf life for the material, the dispensing mechanism vill eject the cassette as above, and the control 21 vill cause to be ;232064 ;-17- ;provided a suitable varning to indicate Co the operator that a new cassette should be utilized. _ ;Assuming the cassette is acceptable, the motor 95 will continue to drive the cassette into the mechanism. As the cassette reaches a fully inserted position, the sensor 99 detects the cassette interruption at the hole 68 in the edge of the cassette. The sensor 99 signals the motor 95 to stop and reverse its direction causing the drive roller 94 to rotate in a direction to move the cassette a short distance out of the mechanism, to position the cassette so that the first cell 30 on the trailing end of the cassette is properly aligned to be pierced. The spring loaded pawl 96 permits such movement until it encounters the grooves 64. The cassette is stopped by the pawl one station before the first cell. The detector 98 senses whether the foil 62 in the opening 52 associated with the first cell to be utilized is still intact. If the foil has been broken, the cassette vill be advanced to the next cell. The foil will again be examined and the process repeated as necessary until an intact cell is located or the entire cassette is ejected. Assuming the foil is intact, the cassette is then advanced to the first cell position. ;Before the hydrogen peroxide is injected, a vacuum is applied to the chamber 10 by way of the conduit 14. To initiate the fluid injection process, pressurized fluid is applied through the conduit 87 to extend the actuator rod 85 and thereby move the cam 84 from its position wherein its surface 84a is engaging the roller 82 onto the sloping cam section 84b and then into the section 84c. ;Before the cam movement starts, the cassette 18 and the adjacent components are poeitioned, as indicated schematically in Fig. 13. There is some clearance between the cassette 18 and the adjacent sealing members, and the needles 91 and 152 have not penetrated the cassette. Movement of the cam to a position wherein the lowest portion of the cam slope 84b is engaging the roller 82 as ;232064 ;-18- ;seen in Fig. 14, forces the clamp plate 76 downwardly, which in turn presses the saddle 80 downwardly_moving the clamp 88 into engagement with the upper surface of the cassette 18. This downward movement occurs against the upward forces of the springs 74 and 78. Also, as the lower surface of the cassette engages the upper sealing ring 158b of the seal 158, that seal is moved downwardly against the force of the spring 164. ;Several functions have occurred as a result of this downward movement. The O-ring 90 on the top side of the cassette, has been compressed against the cassette to create a seal in that location. That O-ring, of course, surrounds the aperture 46. Also, the needle 91 has pierced the indicator strip 47 and partially entered the aperture 46. Thus, the needle 91 is in communication with the compartment 42 Including the space above the pressure side 32 of the cell. The sealing ring 158b surrounds a hole 49 leading to a cell 30, in the lower surface of a cassette to create a seal at that location by compression of the ring 158b. Further, the seal member has been moved downwardly sufficiently far that the needle 152 extends upwardly into the hole 49 and pierces the delivery side 34 of the cell 30. The internal seal 158c on the lower end of the seal member slides on the needle 152 but maintains a seal at that location. ;Since a pair of cell piercing assemblies are provided, the cassette has also been moved onto the other piercing assembly 150. This creates a seal in that area and the needle 152b harmlessly extends into the socket 50. Also, a blade 168 positioned on the frame 70 adjacent the lower side of the cassette along one edge is aligned to enter the hole 52 and rupture the foil 62 to provide an indication that the cell associated vith that hole has been pierced. ;Continued extension of the actuator rod 85 moves the cam 84 off the section 84b onto the section 84c which does ;232064 ;-19- ;not depend as far as the section 84b, as indicated schematically in Fig. 15. This allows the sprang 74 to urge the platen 72 and the cassette 18 to return upwardly a small amount, vhich is sufficient to move the cassette avay from the needle 152 so that it no longer is extending into the cell 30. The seals produced around the hole 49 and the aperture 46 in the cassette remain intact, however, since the cassette is still under downward pressure* Movement of the cam to its fully extended position actuates a suitable sensor (not shown) to initiate the flov of pressurized air through the flexible conduit 93 through the needle 91 into the compartment 42 creating pressure against the pressure side 32 of the cell, forcing it dovnvardly against the fluid 31 in the cell. The fluid is thus forced out of the cell through the hole 49 and into the needle 152. The pressure side 32 of the cell fully inverts against the inner surface of the delivery side 34 of the cell so that the entire volume of fluid vithin the cell is forced out of it. The outlet from the cell is formed at its lovermost point so that all of the liquid contained in the cell is emptied even if air is present in the cell. Fluid flowing out of the cell 30 is forced dovnvardly through the needle 152 through the opening 113 in the diaphragm 112, through the radial passage 120 into the valve inlet recess 116 surrounding the valve seat 110.

The pressure applied by the pneumatic air pressure against the pressure side 32 of the cell is sufficient to overcome the valve closing force on the diaphragm 112, vhich includes the dovnvardly urging force of the injector valve spring 132, the ambient air pressure, and also the small effect of the vacuum applied to the central dovnstream side of the diaphragm. It should be noted that the area of the diaphragm receiving the inlet pressure is relatively large. The diaphragm 112 moves avay from the 232 0 64 valve seat 110 so that £luid can flow through the outlet passage 111 and the nozzle 140 into the chamber. 10. This injection of the fluid takes place very quickly, and as soon as the fluid has been injected, the spring 132 immediately reacts against the piston 130 to move the valve element once more into its normal valve-closed position. Although the passages on the upstream side of the valve seat are properly sealed, it is desirable to positively close the valve as quickly as possible so as to minimize the possibilities of the vacuum in the chamber being affected.

The air pressure through the flexible conduit 93 is then withdrawn, and the cam 84 is retracted. The detector 98 has observed through a hole 52 that the next cell in line has not been used. Thus, the solenoid 97 is actuated to release the pawl 96, and the motor 95 is energized to cause the roller 94 to move the cassette outvardly one position, at vhich time the pavl 96 once more engages a groove 64 to hold the cassette in proper position for the next cycle.

It should be appreciated that the fluid in the cell 30 vas positively and quickly injected into the chamber vith volumetric accuracy. The only fluid not Injected is that remaining in the fluid passages betveen the cell vail 32 and the valve seat 110. This quantity is very small in relation to the volume of the cell 30, even though the cell volume is small. Moreover, this dead volume is only for the first cell, in that injection of the fluid in the second cell vill inject most of this small remaining amount and leave a similar remaining amount, so that volumetric accuracy is obtained.

The next step in the sterilizing cycle i8 that the injected hydrogen peroxide is alloved to permeate onto all the surfaces of the items being sterilized, and elcctrical energy forming a plasma is eventually applied. Further details regarding such process are set forth in the above- 232 0 64 referenced patent. The cassette and the fluid dispensing mechanism are in position to repeat the cycle upon receipt of an appropriate signal applied to the actuator which moves the cam. All of the cells vithin a cassette can be sequentially used in this manner. The microprocessor 21 controlling the operation counts the cells as they are used, and when all have been used, the spent cassette is automatically ejected. Alternatively, the absence of foil in a hole 68 can be used to indicate that all of the cells within the cassette have been used'.

While the invention has been described in connection with injecting liquid into a chamber for a sterilizing cycle, it should be understood that the system is useful for injecting any type of liquid into a chamber. Further, the injection does not have to be in connection with a sterilizing cycle. Also, the Injection system can be useful for injecting liquids into containers other than vacuumized chambers, although the injector valve is particularly useful in connection with a vacuum chamber.

Although the preferred form of the cassette and the dispensing from the cell has been described above, there are, of course, other alternatives. For example, the cell piercing element need not be a tubular needle. Instead, liquid could flow around a puncture element. Also, the need for such an element can be eliminated by bursting a cell. Referring to Fig. 7a, a cell delivery wall 34a is formed with a weakened or thinned central section 34b that vill burst or rupture at a predetermined pressure. In addition to eliminating the piercing tip, the corresponding seal needs and cassette positioning steps can be simplified. The wall section 34b can be formed by coining a regular wall or by forming the vail thinner. Related to the foregoing, the wall 34 can be eliminated by forming and filling a cell using the vail 39 as the bottom vail of the cell and forming a thin section at the outlet location that is either pierced or burst. Also o •a®"1 232064 r^; alternatively, Che section 34b may be a separate layer bonded to the cassette wall 39. ^ O G 232064

Claims (8)

WHAT WE CLAIM IS:

1. A container for containing fluid comprising a delivery- wall and a pressure wall, said delivery wall having a concave inner surface with a first spherical radius; said pressure wall having a concave inner surface with a second spherical radius, having a periphery sized to mate with the periphery of said delivery wall, the peripheries of said walls being bonded together with their concave walls facing each other to define a sealed container, said pressure wall being flexible and said first spherical radius being larger than said second spherical radius so that, once an aperture is formed in a weakened section of said delivery wall, said pressure wail can be pressed into engagement with said delivery wall and said pressure wall will nest precisely within said delivery wall to force substantially all of the fluid out of said container when said container is emptied.

2. The container of Claim 1, wherein said walls are each formed of plastic which is flexible but substantially inelastic.

3. The container of Claim 1, wherein said walls are formed in plastic sheets having one or more additional pairs of mating walls to form additional containers thereby creating a pack of containers interconnected by said shee - 24 - 232064

4. A cell pack comprising means defining a plurality of the containers of Claims 1 or 2 interconnected in spaced relation.

5. The cell pack of Claim 4, wherein said means comprises a pair of sheets each having a plurality of concave recesses, with the recesses of one sheet being joined about their peripheries to the recesses of the other sheet to form said containers»

6. The cell pack of Claim 4 or 5, wherein said containers are interconnected by a base sheet.

7. The cell pack of Claim 6, wherein a machine readable code is provided on said base sheet providing information about the identity and filling date or safe use expiration date of said fluid.

8. A method of manufacturing the cell pack of any one of Claims 4 to 6, comprising the steps of: forming a plurality of shallow recesses in one flexible sheet; forming mating shallow recesses in another flexible sheet; and bonding the sheets together around the peripheries of said mating recesses with the recesses facing each other, thereby forming the cell pack of any one of Claims 4, 5 and 6. W.Z. PATENT OFFICE 16 APR 1991 " ATTORNEYS FOR THE APPUCAtff -