CA1336246C - Fluid injection system pump and pumping methods - Google Patents

Abstract

A pumping apparatus is described for use in a fluid injection system. The pumping apparatus receives an unpressurized container having a predetermined quantity of liquid therein. An outlet valve is also provided and has an inlet passage, a valve seat, an outlet passage, a flat flexible, pressure responsive valve element, engaging the valve seat, and exposed on one side to the passages. A spring urges the element into closed position on the valve seat. A mechanism cooperates with the container for forcing fluid out of the container into the valve inlet passage so as to open the valve element temporarily and permit fluid to flow into the valve outlet.

Description

FLUID INJECTION SYSTEM PUMP AND PUMPING METHODS
Field of the Invention The present invention relates to 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, and more particularly, to a pumping apparatus for use in the injection of the fluid.
Background of the Invention U.S. Patent No. 4,643,876 discloses a steriliza-tion system in which 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 com-mercialized 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 material 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.

- la - 1 3 3 6 2 4 6 ._ 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 have adequate safeguards with respect to human error in view of the crit~cal nature of sterilization of medical item6. Minimizing the chance of human error i6 thu6 important. Al~o, the apparatus mu6t haYe adequate reliability for heavy u6age of the apparatu6 over an extended period of time.
Prior fiuid in~ection sy6tems in steriliz~ng spparatu~
do not provide the desired features. In one known sy~tem, ethylene oxide gas is sealed under its own pressure in a container and then dispe~6ed a6 needed. This approach is not practical with B liquid delivery sy~tem in that a ga~eou~ propellant contalned in the liquid is not acceptable in the sterilizing process. Also, delivery pressure decayfi during the ~elivery proce6~, whlch can resul~ in an undelivered dead volume, and degradation in the quality of atomization of the fluid 88 it enter6 the chamber.
Thu~, a need exists for an improved ~ystem.
Summary of the Invention Briefly stated, pumping appsretus for the fluid in~ection system disclo6ed herein provide6 a fluid supply in the form of a prepackaged closed cell containing a know~ volume of fluid. The apparatus further includes a Dechsnism for receiving and po~itioning the cell, a~d a cell opener assembly cooperating with the mechanism for penetrating the cell to form an outlet from the cell. A
devlce cooperating with the cell and the receiving mechanism forces the entire volume of fluid out of the cell, thus providing a convenient pumping apparatus for providing 8 known quantlty of fluid.
Preferably, the cell ~ 8 Qne of a serie~ of cell~
formed on a connecting flexible sheet wherein the sheet i6 c~ptured between ~at~ng sect'ons of a rlgid cassette.
This enable~ the fluid for ~the pumping &pparatus to be provided ~n a form to be automatically acted upon by other component~ of that apparatu~. Preferably the cell opener assembly includes a tubular needle ~hich enter~ through a hole in the cs66ette to pierce a cell and form an outlet. As a convenient me~n~ for forcing the fluid out of the cell, pneumatic pressure i8 applied through aperture in the ca~sette 80 that pre6sure formed in a S compartment in the cassette ~d~ace~t the cell force~ the fluid out of the cell. The cell opener assembly include~
e seal sl~rrounding the needle which sealingly engage6 the ca~ette around the hole in the cassette. On the other side of the cassette, a sealing element engages the ca~sette~ surrounding the sperture through which pneumatic pre6sure is applied to the exterior of the cell within the ca~sette.
The pumping spparatu6 slso includes a mechanism for pressing the css~ette onto the needle to pierce the cell. A cam control6 the pre~sing operation 80 a~ to f1rst csuse the needle to pierce the cell delivery wall, snd then allow the ca~sette to be retracted slightly 80 that the pressure wall on the opposite side of the cell i~
not pierced a8 it is inverted into engagement with the 2~ delivery wall as the fluid is being forced out of the cell. As the cassette withdraw~ to this slightly retracted position, the cam initiate~ the application of pneumatic pressure to force the fluid out of the cell.
At the completion of a cell emptying operation, the cam returns to its initial position, and an ~rrangement is provided for moving the csssette to a second po6ition wherein 8 second cell in the casBette iB located 80 a~ to cooperAte ~ith the cell piercing and fluid forcing apparatus. The cassette positioning compo~ents preferably include a positioning pawl which ~olds the caesette in a de6ired position and which is then r~le~sed to allow a roller engaging the cassette exterior to slide the csssette to a s2cond position wnere it 18 held bv the pawl.
The pumping mechanism further includeg an in~ector valve having it~ inlet connected to the needle ~hich ducts ~_ 1 336246 the fluid from the cell. The injector valve employs a pressure responsive element that is urged by a spring into closing position. The fluid forced out of a cell is ducted into the injector valve where it reacts against the valve element to move the element into open position allowing the fluid to be ejected from the valve. The valve element which is in the form of a flexible diaphragm has one side which engages the valve seat as well as an inlet passage surrounding the valve seat. The other side of the diaphragm is exposed to ambient pressure and the force of the valve closing spring.
Pumping methods provided by using the pumping apparatus are also part of the invention.
According to a further broad aspect of the present invention, there is provided a pumping apparatus for a fluid injection system and comprising means for receiving an unpressurized container having a predetermined quantity of liquid therein. An outlet valve having an inlet passage, a valve seat, an outlet passage, a flat flexible, pressure responsive valve element, engaging the valve seat and being exposed on one side of said passages is also provided. A spring urges the element into closed position on the valve seat. A mechanism is also provided for cooperating with the container for forcing fluid out of the container into the valve inlet passage so as to open the valve element temporarily and permit fluid to flow into the valve outlet.
According to a still further broad aspect of the present invention, there is provided a pumping apparatus which comprises means for receiving a cassette containing a plurality of individual sealed cells containing fluid. A fluid coupler is provided `` 1 336246 _ 4a -_.
for temporary connection to the cell. An injector valve having an inlet is joined to the coupler and a normally closed pressure responsive valve element is urged by inlet pressure to be opened. Means cooperates with the cassette and the coupler to allow the coupler to communicate with a cell within the cassette. Means cooperates with the cassette to apply pressure to a flexible wall of the cell to force fluid out of the cell through the coupler to open the valve and allow the fluid to be forced out of the valve.
Other aspects of the fluid injection system disclosed herein are claimed in separate copending applications.
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 the 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 fuid 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;
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. l;

~5~ 1 3 ~6246 Fig. 9 i6 sn exploded per~pective vlew of the in~ector valve as6embly of the invention.
Fig. 10 is an exploded per6pective view of the cell piercing Rnd floating ~eal mechanism which is ~ portion of the assem~ly of Fig. 9.
Fig. 11 is an enlarged perspective view of the ln~ector valve assembly.
Fig. 12 is a cross-sectional ~iew of the in~ector valve as6embly on line 12-12 of Fig. 11, together with a cro~6-sectional view of the air delivery system for compressing a fluid cell in the cassette.
Fig~. 13, 14 and 15 are schematic views of the fluid ~n~ection system in operation;
Detalled De~cription of the Preferred Embodiment Referring to Fig. 1, there i~ schematically illu6trated a cylindrical chamber 10 having a door 12 on one end. The chamber i8 connected to e suitable vacuum source by ~ay of a conduit 14. Ihe chamber i8 adapted to receive items to be 6terilized, such as surgical instruments, in accordance ~ith a method outlined in the above-referenced patent, wherein e liquid such 88 hydrogen peroxide i8 introduced into the chamber. ~or delivering such fluid, in ~ccordance with the pre&ent invention, there is provided a fluid in~ection system 16 po6itioned ad~acent to the chamber 10.
The system includes ~ cassette or cartridge 18 containing the fluid to be in~ected, a cassette receiving, positioning and clamping mechanism 20, and ~ fluid in~ector valve 88 sembly 22 ~ounted on ~nd lnterconnected with the chamber. The flu~d in~ector system 16 can be thought of a8 A pUmp ln which the cassette 18 is in~erted into the cassette receiving mechanism 20 ~od doses of the ~edi~ ~ontained in the cassette ~re ~utom~ically in'ected into the chamber during automated sterili~iog cycle~.

Ca~sette The cas~ette 18 is ln the form of 8 flat, rectangular rigid structure preferably made of pla~tic or other suitsble m~teriAl. The form of the c~ssette illustr~ted includes an upper housing section 24 ~hich mates with the lower section 26 to c~pture and enclose a cell strip ~ssembly 28 or cell pack. The sectio~s-are held together by fssteners or other suit~ble means. The pack ~ssembly ha6 a rectangul~r shape, with sllghtly smaller dimension than that of ~ections 24 snd 26 such that the pack fits within the confines of the outer section~, as ~ay be seen from Fig. 7.
The cell pack includes a plurality of fluid cells 30 arranged in the form of two rows of sp~ced cells with the cells of one row being offset in a lengthwise direction from the cells of the ~d~scent row and parti~lly positioned between the cells of the Ad~acent row. Such an errangement provides ten cells in the example shown in a compsct space. When considering the sequence of the cell~
in the long~tudinal direction of the assembly, this plsce~
the first cell in one row and the second celL in the other row, etc.
As seen from Fig6. 5 and 6, each cell is formed by a pair of flexible walls lncluding a delivery ~all or side 34 ~nd a pre~sure vall or side 32. As seen from Ffg. 5, these walls have a 6pherical exterior and sre bonded togetber sround their periphery, forming a ~oint or seam 36. These walls 32 and 34 are preferably each formed or molded in a plastic sheet on a spherical radius. The rsdius 35 of the presfiure side 32 is ~lightly 8maller than the radius 33 of the delivery ~ide 34 in ~ ~mount equal to the formed film thickness 80 that the presEure si~e ~ill nest ~er~ectly into the delivery side when the cell is emptied. ThiB contributes to the ~ccur~cy of the amoun~ of fluid delivered and avoids desd volume. The cells ~re filled vith l~quid 31 of a precisely known 1 3~62~6 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 with 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 within 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 with operations other than in connection with sterilizing apparatus.
The lower cassette section 26 is formed with a plurality of walls 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 with a plurality of circular walls 40 which, in cooperation with the walls 38, form a plurality of circular compartments 42 each of which confines a cell 30. The lower section has a flat annular wall surface 44 surrounding the recess 39 which with the lower circular edge of the wall 40 securely holds the cell bonded joint 36 to seal the compartment 42 in that area. The recess 39 is likewise 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 32 of a cell is spaced from the flat wall of the upper housing section 24 so that a space or pressure cavity is formed thereby. The pressure side of each compartment 42 is formed with an aperture 46 that interconnects the compartment 42 with 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 row of cells and -8- ~ 33 6 ~ 4 6 compartments. This arrangement create6 8 Bingle row of apertures 46.
The row of aperture6 46 i8 covered by an indicator strip 47 having a lower layer 47a which engages the S cassette surface aDd iB exposed on one side to the compartment 42. This lower layer 47a is treated chemically such that if it i6 exposed to hydrogen peroxide, it will change color, thus lndicating that the cell 30 in that compartment is leaking. Of course, if 10 material other than hydrogen peroxide i6 confined in the cell, the layer 47a will ~e treated with ~In appropriate ~aterial which will indicate the presence of that fluid.
A~ upper layer 47b i6 a fil,m of pla6tic to protect the iodicator layer 47a from meterial other than the fluid in ~5 the cell and to trap any fluid that has escaped.
The lower ca~sette section 26 is formed with a hole 49 which i8 centrally po6itioned in the rece6s 39 and Witil re6pect to the cell 30 in the compartment 42. Ttli6 creates two rows of holes 49 which may be ~een in 20 F~g. 3. In addition, there iB formed a socket 50 in the lower housing section 26, spaced laterally from each hole 49, thufi positioning such ~ocket between a pair of compartments in the ad~acent row. Since a similar 60cket 50 i8 laterally aligned ~ith the hole in esch socket, thi6 25 creates two rows of socket6 50, each aligned wlth a row of holes 49, a6 may l~e seen from Fig. 3. These sockets extend inwardly a~out half way into the cassette, the socket upper surface, as ~ie~ed ln Fig. 7, being approximately flush with the annular wall 44 surrounding 30 e~ch compartment.
Both caBsette 8ection6 are formed with 8 plurality of aligned openings 52 arranged in a row that extends parall~l t~ the longitudinal edge of the cas6ette, ~paccd inwardly a ~hort distance from the right edge, a8 viewed 35 in Figs. 2 a~d 7. Al~o formed in this same row i8 a 6lot 54 that extends through both section6. The 610t i~ at the -9- 1 ~ 36 246 entry end of the ca66ette ~t the end of the row of opening~ 52. A tran6parent edge portion 56 of the cell pack inter6ect~ the openingE 52 and the slot 54. More specifically, the upper cassette section 24 i6 formed with a serie~ of pro~ecting ~all portions 58 which define the portion6 of the slot 54 snd opening~ 52 which are in the upper section. The6e pro~ections 58 engage the strip portion 56 and capture it against ~he inner surfsce of the cassette lower section 24.
A layer of foil 62 i8 positioned on the plastic sheet 56 in that locstion snd mày be seen through transparent plastic. The foil is perforsted a6 an indicator when an ~8~0ciated cell 30 i8 used, a8~will be de6cribed below.
The ca~sette is further formed with e plurallty of sp2ced groove~ 64 on one edge of the upper surface of the cassette upper section 24, the grooves being transver6ely aligned with the opening~ 52 ~nd ~xtending from the openings to the edge of the c~sette. The spacing between the grooves and between the openings is equal to the spacing between the apertures 46 and holes 49 in the c~ssettes. There is a groove 64 transversely sligned with each compartment 42. However, it is not necessary that they be aligned; only that one groove is ~ssociated with each compartment, and that an offset (if sny) is constant. In addition, there i8 a groove on the entry end of the ca~sette which i8 spaced forwardly from the first compartment, snd three grooves on the trsiling end of the ca~sette ~hich extend beyond the last compartment 42. In the particular system disclosed, the first t~o and the last one groove ~re included for aesthetlc ressons only.
A180 po6itioned on the surface of the cell strip portion 56 i~ ~ ~sr code 66 located at the entry end of t~e cassette. Thig bar code ~hich identifies ~nd date~
the cell pack is sligned with the slot 54 80 that the bar code csn be read through the slot. The date is preferably t 336246 - 1 o -the date the cells were filled ~ith fluid or the safe u~e expiration date of the flu~d.
An indicator 8 trip or label 67 ~B attached to the lower surfsce of the cassette and covers the hole6 49, ~
~ell as the sockets S0, the openings 52 and 8 portion of the slot 54. A window 69 ln the lsbel 67 permit6 partial viewing of the bar code 66. A strip layer 67a indicate6 the existence of cell leakage, and a plastic layer 67b Reals ~he ares and protects the indicator layer.
~8 seen from Fig. 3, there is provided a sen~lng hole 68 on the edge of the ca~sette near the trailing end of the cassette. Thi8 hole i~ used as 8 stop or iodicator in connection vith the positioning of the csssette in the dispensing ~echanism~ a~ to be subse~uently described.
1~ The cassette 18 provides a convenient package for presenting mea~ured quantities of the flu~d to be dispensed. Although the structure uniquely lncludes many features, lt i6 inexpen6ive in mass production, and thus ~8 practical a~ a dlsposable ~tem. 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. Likewise, it present~ a ssfe and protected storage means for the fluid 80 that it i8 no~ contAminated.
Càssette ReceivinR and Clamping Mechanism The ~echanifim for receiving 8 cassette 18 includes an outer hollo~ fra~e 70 ~hich is mounted o~ the-sterilizing chamber 10, preferably by being positioned on the in~ector ~alve assembly 22, a8 seen in Fig. 1. Positioned within this frame 70 is ~ platen 72 which is ~dapted to receive a cassette 18, as seen in Fig~. 1 and 8. The platen i8 forced upward by suitable spri~gs 74. A clamping plate 76 is rivoted to the rear portion of the fra~e 70 and is forced up~ard by suitable ~prings 78 BO as to create a space ~ith the platen 72 for receiving the cassette 18. A
clamp saddle-member 80 ~tr~ddles a csssette '8 and i6 pi~otally mounted by pin~ 81 carried on arms 768 depend$ng from the clamping plAte.
~ o~itioned on the top side of the clamp plate 76 i~ a roller 82 which support~ the forw~rd end 84a of an elongated cam 84. The cam further includes a central section 84b which slopes downwardly and rear~ardly, and a trailing horizontally extending section 84c which i6 at a lower level than the forward sect$on 84a. The cam is ~ounted on an actuator rod 85 extending from an actuator housing 86 which in turn i6 supported on a f$xed structure such as the frame 70 by suitable means (not shown). The actuator i8 in turn connected to a source of pressurized fluid by 8 conduit 87, as seen in Fig. 1 but, of cour6e, could be energized by other ~eans, such a8 electric.
15On the ~addle clamp 80 i~ a clamp assembly 83 for pres6urizing or forcing fluld 31 out of a cell 30. The ~ clamp assembly 83 includes a generally cylindrically shaped clamp 88 which extends through the clamp saddle 80 and includes a flat lower surface adapted to engage the upper surface of a css6ette 18. An snnular spring element 89 captured in a groove in the cla~p 88 extends outwardly and downwardly to react sgainst the top 6urfsce of the clamp saddle 80 to hold the clamp 88 in position on the saddle 80. An 0-ring 90 positioned within a shallow 2~ reces~ in the face of the cl~mp 88 e~tend6 slightly below the face. A tubular piercing needle 91 i8 mounted within a pss~age 92 in the clamp 88, with the piercing tip of the needle e~tending slightly below the lower surface of the clamp and the 0-ring 90. The passage 92 in the housing is 3~ n turn connected by a suitable fle~ible condu~t 93 to a source of pres~urized sir.
To po~itio~ the casset~e lB, there is a provided a drive rolier 94 rGtstably mounted on the fr~me 70, which frictionally engages the upper surface of the cassette, the roller being driven by a motor 95 al80 mounted on the frame 70. For stopping the cassette in proper pos$tion -12- ~ 33 6 ~4 6 with re6pect to a cell 30, there i6 provided a spring lo~ded pawl 96 which cooperate~ wlth the groOVeB 64 on the upper surface of the ca~sette. The pawl ~8 ~ovable by 8 soleDoid 97 ~ounted OD the frame 70. Al60 provided i6 a S ~ensor 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 with the openings 52 and the slot 54 when a ca6sette is inserted into the mechanlsm 20. Al60 po6itioned on the frame 70 is a detector g9 (not shown in 1Q detail) locsted to observe the edge of the ca66ette a6 it moves within the cas6ette positioning mechsnism. A
schematically indicated microprocessor 21 connected to the detector6 control6 the operati~n of the mechanism 20.
In~ector Valve A~6embly lS Turning now to Figs. 9, 1~, 11 and 12, it may be seen that the in~ector ~alve as6embly 22 includes a mounting body lO0 which is ~elded or otherwise ~uitably secured to a wall 11 of the chPmber 10. The in~ector body 100 hss a cylindrical interior in ~hich is positioned ~ating sections 102 and 104 forming a valve body or hou6ing.
The6e sections are clamped together by a spanner nut 106 or other suitable means which thresd6 into the interior of the body 100, vith a washer 108 positioned bet~een the nut 106 and an outwardiy extending flange on the upper ~alve housing section 102.
The primary housing ~ection 104 includes a centrally located, upwardly extending anDular valve seat 110 surrounding the entry to an elongated valve outlet pas6age lll in the pr~mary sectio~ that iB covered or closed by a large, flat flexible diaphragm 112 which forms a ~ovable, pressure-responslve valve element for controlling flow through the valve. ~he diaphr&gm 112 fit6 within a circular, flat recess 114 formed in the primary hou6ing section 104. The recess 114 is flush with the valve seat 3~ 110. Formed in the central portion of the rece~6 114 i8 a smaller diameter shallow annular rece66 116 surrounding -13- 1 3 36 2 4b the annular ~alve seat 110 and forming a portion of an inlet passage to the valve seat 110. The radial dimension6 of the recess 116 i8 qu~te large relatlve to its depth such that a lsrge valve opening force i6 generated with negligible fluid volume. For example, in one form of the invention the recess 116 depth is about .007 inch and the recess dismeter is about .9 inch creating a volume of about .004 in3.
Also formed in the lower hou6ing section 104 are a 1o pair of radially extend~ng, circumferentially ~paced, shallow pa~sage~ 120 which open on their rsdi~lly inner end~ to the inlet recess 116. The radially outer ends of these ps6sage~ are aligned ~it~ openings 113 formed in the flexlble di~phragm 112 and aligned ~ith ~mall diameter 1~ passages 122 extending in an a~ial direction through the upper valve hou~ing section 102 radially outwardly from the central space 131. A pair of positioning pins 124, shown in Fig. 9 (only one of which i8 shown in Fig. 12), e~tend through radislly outer portions of the valve housing section~ 102 and 104, the outer periphery of the diaphragm 112 snd into a socket in the valve assembly body 100. These pins 124 orient ~he di~phragm 112 in the upper hou6ing section 102 80 that the holes in the diaphragm and the pa~sage6 in the upper housing section are sligned with the radially outer ends of the psssage~ 120. They al~o align the entire in~ector body assembly to the cassette receiving mechanism.
An outer 0-ring 126~ positioned within 8 groove in the - upper hol~sing section 102, sesls the ~alve inlet pAsssge radially out~ardly from the passage 122. Correspondingly, an inner 0-r~ng 12~ prevents fluld flow bet~een the upper side of ~he diaphragm 112 and the upper hous~ng section 1~2.
Positioned on top of the di~phragm 112 is ~ movsble 3~ piston 130 located within a suitsbly formed, centrally located space 131 ~n the upper hou~ing ~ection 102 which -14- 1 33 6 2 ~6 i~ open to smbient pre~sure. A lower head portion 130a of the piston 130 engage~ the top side of the diaphragm 112 opposite from the valve seat 110. A compression spring 132 surrounds ~n upper cylindrical portion of the piston 130 and react~ against a shoulder 130c to force the pl~ton 130 into valve clo~ing ~osition ~gain~t 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 fastener~ 138 to the upper end of the upper valve houEing section 102.
Positioned on the lower end of the lower valve housing ~ection 104 is an ~tomizing nozzle 140 clsmped ~gainst a filter 142 and an 0-ring 144 by me~ns of a surrounding 61eeve nut 146. An atomizing finger 148 secured to the nozzle 140 i6 aligned with an opening through the nozzle and with the valve outlet passage 111 to fac~lit~te the fitomiZing of fluid e~ecting from the outlet.
Cell Piercing/Flo~ting Seal As~embly Still referring to Figs. 9-12, the in~ector valve assembly further includes a cell ope~er assembly or a cell piercing and floating seal assembly 150. The assembly 150 which forms a fluid coupler include~ a conduit in the form of a tubular needle 152. The needle i8 secured to ~
~urrounding needle ~upport ~ember 154 positioned within a ~ocket 156 formed in the upper surface of the upper valve hou~ing section 102. The ~oeket is ad~acent to but spaced radially outwardly from the central ~pace 131. The lower portion of the needle fits closely within the inlet passsge 122, ~hile the sharp upper end of the needle extends up~ardly $n po~ition to pierce A ~luid cell 30. A
resilient tubllla seal element 158 having ~n a-.ial bore therein ~urrounds the upper portion of the needle 152.
tubular sol!ower 1~0, msde o ~aterial more rigid ~han the 6eal 158, eng&ges the lower portion of the seal 158. A
tubular sleeve or guide 162 surrouDds th~ seal 158 end extends through an opening 161 in the retainer 136. The -lS- I 33 6 24 6 guide 162 i~ provided with an outwardly extending flange ~hich engage6 the lower surface of the plste 136, and the lower surf~ce of thi~ flange engages an outwardly extending flange 158a on the lo~er end of the seal 158.
A compres~ion spring 164 e~tends between a flange 160~
on the follower 160 and an outwardly e~tending flange on the lower end of the needle support lS4. Thi~ spring biase~ the follower 160, the ~eal lS8 and the guide 162 upwardly ~gain6t the retainer plate 136. The spring also bia~es a small 0-ring 166 into a groove in the hou6ing section 102 surrounding the needle 152 80 as to prevent fluid flow bet~een the passage 122 and the soc~et 156.
The upper end of the se~l 158 includes an upwardly e~tending ~nnular face portion lS8b ~hich engages the lo~er ~urface of a cassette 18 to form a seal therewith.
The bore within the seal lS8 include6 ~n inwardly e~tending seal portion 158c on its lo~er end which resiliently engages the exterior of the needle 152 to form a seal at that location. The central protu~erance on the lo~er end of the seal 158 surrounding the portion lS8c ha~
a conical shape that fits ~ithin a ~ating coDical recess in the upper Qurface of the follower 160. These ~ating surface~, together with the force of 8pring 164, bias the seal portion 158c into engagement ~ith the needle to form a good sliding seal.
AB see~ from Fig~. 9 and 11~ there are 8 pair of cell ~iercing assemblies 150 circumferentially spaced from each other on the housing section 102.
Operation When the system of the invention i~ to be employed J
articles to be 6terilized are ~laced ~thin the chamber 13 through the opening covered by the doo_ 12, ~fter ~hich the door is secureiy closed. A c~s~e~te 1~ contalning a fresh celi pack 2& is selected to be nanually inserted ~5 into the in~ector nechan~ 8~ 20. Before the ca~ette is inserted, the indicator strips 47 and 67 are observed to -16~ 6 24 6 6ee ~hether they indicste thst any of the cell~ are leaking hydrogen peroxide. If a leak exists, the indicator strip on the leak side will have a color ~ndicating such condition, and the ca66ette should not be used. If the cassette i6 in proper condition, the strip 67 is removed by wsy of a suitsble pull ta~ 67c and the cassette is lnserted.
As the cas~ette i~ being inserted, a number of e~ent6 occur. The sensor 99 aligned with the edge of the ca~sette detect6 the presence of the cassette. A signal from the control 21 start~ 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 i8 read by the sensor 98 by way of the slot 54 and the information tran~mitted to the control 21. If the cassette iB inserted backward~ or inverted, the absence of ~sr code information will ceuse the mechanism not to sccept the cassette. If the ca~sette is properly oriented but the strip 67 hss not been removed, only a portion of the code iB seen through the window 69 in the strip 67, causing the ~olenoid 97 to release the pawl 96 and cau6ing the motor 95 to reverse direction to e~ect the cassette.
The bsr code indicates the nsture of the fluid in the cs~sette, which i8 necessary ~ince cassettes containing different sterilants or sterilants of differing volume~
may be utilized with the apparatus of the invention.
Al&o, the bsr code will tell ~the date on which the sterilant pack 28 hss been filled. If wrong material i8 used or the date is beyond an 6cceptable ~helf life for the materisl, the dispensing mechanism wlll e~ect the cassette ax abo~e, and the control ~1 will cause to be provided a ~uitable warning to iDdicate to th~ operstor that a new cAssette shou'd be utillzed.
Assuming the cassette is acceptsble, the motor 95 will continue to drive the cassette into the mechanism. A~ the ca6sette resches a fully inserted pos~tion, the sensor 99 ` -17- 1 33 6 2 46 detects the cassette interruption at the hole 68 in the edge of the cassette. The sensor 99 signals the motor 95 to stop and rever~e its direction csusing the drive roller 94 to rotate in a direction to ~ove the cassette a short S distance out of the mechani~m, to position the cassette 80 that the f-r~t cell 30 on the trailing end of the cs~ette is properly aligned to be plerced. The spring loaded pawl 96 permits such movement until it encounter6 the groove6 64. The cas~ette i8 stopped ~y the pawl one station before the fir~t cell. The detector 98 sense~ whether the foil 62 in the opening 52 assoc~ated with the first cell to be utilized ~8 8till intact. If the foil ha~ been broken, the ca6~ette will be.advanced to the next cell.
The foil will again be examined, and the proces~ repeated tS as neces~ary until an intact cell is located or the entire cassette ~ e~ected. A~6uming the foil is intact, the csssette is then advanced to the first cell po~ition.
Before the hydrogen peroxide is in~ected, a vacuum i~
applied to the chamber 10 by way of the conduit 14. To initiate the fluid in~ection process, pres~urized fluid i~
spplied through the conduit 87 to e~tend the actuator rod 85 and thereby ~cve the csm 84 from lts po~ition wherein its surfsce 84a is engaging the roller 82 onto the sloping cam 6ection 84b and then into the section 84c.
Before the cam ~ovement start6, the csssette 18 and the ad~acent components are positioned, a8 indicated schematically in Fig. 13. There is some clearance between the csssette 18 and the ad~acent sealing members, ~nd the needles 91 and 152 have not penetrated the cassette.
Movement of the cam to a position wherein the lowe~t portion of the cam slope 84b i8 engaging the roller 82 as ~een in Fig. 14, forces the clamp plate 76 downwardly, ~hich ln turn presse~ the ~sddle 80 dow~w~rdly moving the clamp 88 into engagement with the upper surface of the 3; cassette 18. Thi~ dow~ward ~oveme~t occurg against the upward force~ of the spring~ 74 and 78. Algo, a~ the lower surface of the ca~ette engages the upper ~ealing ring 15~b of the seal 158, that seal i8 moved do~nwardly aga~nst the force of the spr~ng 164.
Several functions have occurred a8 a result of this downward movement. The 0-ring 90 o~ the top slde of the cassette, ha~ been compressed aga~n~t the csssette to create a seal ln that location. That C-ring, of course, surround~ the aperture 46. Also, the needle 91 has pierced the indicator strip 47 a~d partially e~tered the aperture 46. Thu~, the needle 91 is in communication with ehe cQmpartment 42 includi~g the space above the pressure side 32 of the cell. The 6eal~ng ring 158b surrounds a hole 49 lead~n~ to a cell 30,.in the lo~er surface of a cassette to create a ~eal at that locat~on by comprefi6ion of the ring 15gb. Further, the &eal ~ember ha~ been ~oved dow~ardly sufficiently far that the needle 152 exte~ds upwardly into the hole 49 and pierce~ the delivery side 34 of the cell 30. The internal ~eal 158c on the lower e~d of the seal member slides on the needle 1~2 but maintain~
a seal at that location.
Since a pair of cell piercing assemblie~ are provided, the cassette has also been 20ved o~to the other piercing assembly 150. This create~ a seal in that area and the needle 152b harmlessly extends into the socket 50. A1BO, a blade 168 posltioned on the frame 70 ad~ace~t the lower ~5 side of the cassette along one edge ~8 alig~ed to enter the hole 52 and rupture the fo~l 62 to provide an lndication that the cell associated ~ith that hole has been pierced.
Continued extension of the actuator rod 85 moves the ~ cam 84 off the ~ection 84b onto the 8eCt~011 84c which doe~
not depend as far a6 the section 84b, a8 indicated schema~icall7 in Fig. 15. This allovs the ~prl~g 74 to urge ~he platen 72 and the cassette 18 to return .~pwardly a s~all amount, ~hich ~8 suff~cient to move the cas~ette away from the needle 152 80 that it no longer ~8 extending -19- 1 33 6 ~ 4 6 into the cell 30. The seal6 produced around the hole 49 and the sperture 46 in the ca6sette remain intact, however, 8 ince the ca6~ette i6 still under downward pres6ure.
Movement of the c~m to it~ fully extended po6ition actuate~ a suitable sensor (not shown) to initiate the flow of pressuri2ed air through the fLexible conduit 93 ~hrough the needle 91 into the compartment 42 creating pre~6ure against the pre6sure ~ide 32 of the cell, forcing ~o it downwardly again6t the fluid 31 in the cell. The fluid i~ thus forced out of the cell through the hole 49 and into the needle 152. The pre6sure side 32 of the cell fully invert~ again~t the inner 6urface of the delivery side 34 of the cell 80 that the entire volume of fluid within the cell i~ forced out of it. The outlet from the cell i~ formed at it~ lowermo~t point 80 that all of the liquid contained in the cell is emptied even if eir i6 present in the cell. Fluid flowing out of the cell 30 i8 forced downwardly 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 vslve seat 110.
The pre~6ure applied by the pneumatic air pres~ure aBain6t the pres6ure 6ide 32 of the cell i8 sufficient to overcome the valve closing force on the diaphragm 112, which includes the downwardly urging force of the in~ector valve spring 132~ the ambient air pres6ure, and also the small effect of the ~acuum applied to the central downstream s~de of the diaphragm. It should be noted that the area of the diaphragm receiving the inlet pressure i6 relatively large. The di~phragm 112 moves away from the valve ~est 110 B0 that flu~d can flow through the outlet psssage 111 and the nozzle 140 into the chamber 10. Ihis in~ection of the fluid takes place very quickly, and 86 3~ 800n a8 the fluid has been in~ected, the spring 132 immediately reacts again6t the piston 130 to move the -20- t 3 36 246 valve element once more i~to it~ normsl valve-clo~ed po6ition. Although the pss~age~ on the upstream side of the valve seat are properly sealed, it i8 desirable to positively close the ~alve a6 quickly as possible 80 as to 5 minimize the pos~ibilities of the vacuum in the chamber being fiffected.
The air pres6ure through the fle~ible conduit 93 i8 then withdrawn, and the cam 84 i~ retracted. The detector 98 ha6 ob6erved through A hole 52 that the next cell in 10 llne has not been used. Irhu8, the solenoid 97 i~ actuated to relea~e the pawl 96, and the motor 95 i6 energized to cau6e the roller 94 to s~ove the cassette outwardly one posltion, at which time the pawl 96 once more engage6 groove 64 to hold the cassette in proper position for the 15 next cycle.
It should be appreciated that the fluid in the cell 30 wa~ po~itively snd quickly in~ected into the chamber with ~olumetric accuracy. The only fluid not in~ected i8 that rem~ining in the fluid pagsages between the cell wall 32 and the valve seat 110. This quantity i8 very 8m211 in relation to the volume of the cell 30, even though the cell volume is small. Moreover, thi~ dead volume is only for the first cell, ln thst iD~ection of the fluid in the second cell will in~ect mo6t of thi~ small remaining 2~ amount and leave a similar remaining amount, 80 that volumetric accuracy is obtained.
The next step in the sterilizing cycle is that the in~ected hydrog,en pero~cide is allowed to permeste onto sll the surfaces of the items being sterilized, and electrical energy forming a pla6ma is eventually spplied. Further details ~egarding such process are set forth ln the above-re~erenced patent. The cassette and the fluid dispen6ing ~echQnism are in position to repeat the cycle upon recei?t of an appropriate signal applied tc the ~ctuator which moves the CQm. All of the cells ~ithin a ca~sette can be sequentially u6ed in this manner. l~e ~icroproces~or 21 ~ - 21 -1 3362~6 _ 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 weakend or thinned central section 34b that will 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 wall thinner. Related to the foregoing, the wall 34 can be eliminated by forming and filling a cell using the wall 39 as the bottom wall of the cell and forming a thin section at the outlet location that is either pierced or burst. Also alternatively, the section 34b may be a separate layer bonded to the cassette wall 39.
This application is a division of Canadian Patent Application Serial No. 567,140 filed May 19, 1988.

Claims (10)

1. Pumping apparatus for a fluid injection system, comprising:
means for receiving an unpressurized container having a predetermined quantity of liquid therein;
an outlet valve having an inlet passage, a valve seat, an outlet passage, a flat flexible, pressure responsive valve element, engaging the valve seat and being exposed on one side to said passages, and a spring urging said element into closed position on said valve seat; and a mechanism for cooperating with said container for forcing fluid out of said container into said valve inlet passage so as to open said valve element temporarily and permit fluid to flow into said valve outlet.

2. The apparatus of claim 1, including a fluid coupling assembly for connecting said container to said valve inlet.

3. The apparatus of claim 2, wherein said container is in the form of a closed cell containing fluid, and said assembly includes means for penetrating said cell.

4. The apparatus of claim 3, wherein said assembly includes a tubular needle which is adapted to pierce said cell and permit fluid to be conducted under pressure through said needle to said valve inlet.

5. The apparatus of claim 3, wherein said mechanism includes means for pressing said cell into said penetrating means.

6. Pumping apparatus, comprising:
means for receiving a cassette containing a plurality of individual sealed cells containing fluid;
a fluid coupler for temporary connection to said cell;
an injector valve having an inlet joined to said coupler and a normally closed pressure responsive valve element urged by inlet pressure to be opened;
means cooperating with the cassette and the coupler to allow the coupler to communicate with a cell within the cassette; and means cooperating with said cassette to apply pressure to a flexible wall of said cell to force fluid in the cell out of the cell through said coupler to open said valve and allow the fluid to be forced out of said valve.

7. The apparatus of claim 6, including means for automatically advancing said cassette from a first position at the completion of a cell emptying operation to a second position to force fluid out of a second cell.

8. The apparatus of claim 7, including means for sensing information on said cassette as to whether said cassette is properly inserted in said receiving means and as to the identity and dating of said fluid.

9. The apparatus of claim 6, including means for sensing whether fluid has been emptied from said cell.

10. The apparatus of claim 6, including means for rupturing a layer of indicator material in said cassette as an indication that fluid has been emptied from an associated cell.