CA1099218A - Pneumatically actuated electronic control for a fluid mixture adsorption separator - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A control system for sequentially communicating a source of pressurized fluid mixture to first and second beds of adsorption material to separate at least one component from the fluid mixture and produce a product fluid. A pressure trans-ducer connected to a supply conduit develops a switching signal corresponding to a predetermined fluid pressure in the fluid mixture communicated to the first and second beds of adsorption material. An electronic controller responds to the switching signal to sequentially develop first and second electrical sig-nals. The electronic controller allows the first and second electrical signals to overlap for a predetermined controlled time period. Valve electrical sequentially respond to the first and second electrical signals to prevent communication of the fluid mixture to one of the first and second chambers while allowing communication to the other of the first and second chambers. A first branch of an outlet conduit connects the first bed of adsorption material to a storage chamber while a second branch of the outlet conduit connects the second bed of adsorption material to the storage chamber. An equali-zer valve located in an intermediate conduit between the first and second branches of the outlet conduit, reacts to overlap of the first and second electrical signals to allow the fluid pressure in the first and second beds of adsorption material to equalize when the communication of fluid mixture to the first and second beds of adsorption material is interrupted to complete a cycle of operation.

Description

~ A~O~ h[ I~ENTION

Oxygen separators such as disclosed in U. S. Patent rlo. 3,880~616, separate fluid mixtures into first and second component parts through the reten~ion of one component in a bed of adsorption material while allowiny the other components to flow therethrough. In order to provide for continuous operation, it is common practice to use two beds of adsorption material simultaneously adsorbing one bed while desorbing the other bed. A firs~ series of solenoid valves associated with the two beds allow ~he ~luid mixture to ~reely flow to a firs~ of the two beds where one component is retained while a product effluent fiows to a storage container through a conduit. At the same time a portlon of the product effluent enters a second of the two be~s and purges the same of the one component prev10usly retained therein. After a fixed period of ti~e, a sTgnal from a timing mechanism deactivates the F}rst series oF solenoi~ valves and activates a sccond series of solenoid valves to reverse the communicat10n oF the fluid mixture from the first of ~he two beds to the second. The flrst bed of adsorption material previously producing the product eff1uant is now purged by a portion of the produc~ effluen~ produced in the second becl~
Theoretically3 the volume o~ fluid mixture passing ~hrough the first and second beds of adsorption material should be equal. ~IoweYer in practice it has been observed that the beds of adsorption materials are nearly always different. Such difference can result from minute changes in stze between the beds, variations in the density oF the beds, and variations in the quality of the ~eds such as porosity and moisture content. In addition, a ~ew seconds change in the operation oF the solenoid con~rol valves by the timing mechanism can cause a degradation of the beds.
Thus, one of the two beds is always produc1ng ~ore o~ a product effluent than the other. The overproduclng bed experiences a component breakthrough wnich dilutes the product efFluent during its aclsorption part of the operational cycle while the underproducing bed has an excessive amount :~ .

of the component retained therein at the initiation of its adsorption cycle. The underproducing bed never reaches ~ts output potential since the adsorption cycle is terminated before the product effluent output peaks.
One method o~ pro~iding identical beds re-~uires the testing of the adsorption capaci~y of the beds as they are produced and thereafter selecting matching beds of the same capacity for each unit.
Unfortunately, this type of quality control does not lend itself for rapid manufacturing production.
Another method of acquir;ng optimum output from an oxygen separator requires the use of an electrical timer whereby the operation of the solenoid control valves can be varied to match the adsorption capacity of the beds. The undexproducing bed cycle of adsorption is lengthened while the overproducing bed cycle is shortened until ~oth beds are operating ; at top efficiency. EIowever~ this solu-tion is only temporary since after an extended period of time the beds become unbalanced in the opposite direction since the retained component is never completely purged from the one bed.
In copending Canadian Patent Application 296,823 filed February 13th, 1978 a pneumatic logic sequencer is disclosed for controlling the transfer of the pressurized fluid mixture between the first and secoIId beds of adsorption material. A first pressure sensor connected to the first bed of adsorption material and a second pressure sensor connected to the second bed of adsorption material supply the logic sequencer a pneumatic signal representative of the fluid pressure in the first and second beds of adsorp-~. ~ h .

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tion material, respectivel~. In xesponse to a predetermined pressure differential, the logic sequencer transfers the pressurized fluid mixture to the bed of adsorption material having the lower fluid pressure.

SUMMA:RY OF q'HE INVENTION
In evaluating the operation of the oxygen separator apparatus, it was discovered that the fluid pressure in the supply conduit varied as a :Eunction of the rate of adsorption of components by the adsorp-tion material and the fl~w of the fluid mixture through a bed of adsorption material being pressuri~ed.
Thereafter, it was determined that an oper-ational s~gnal could be derived from a single pressure transducer placed in the supply conduit to control the se~uential transfer oE the operation suppl~ of fluid mixture between the first and second beds of absorption material whenever a predetermined fluid pressure con-dition was present in the supply conduit. The oper-ational signal from the pressure transducer activates an electronic controller mechanism wherein first and second electrical signals are séguentially produced.
The duration of the first and second electrical signals being a function of a fixed time period plus the duration of the operational signal as determined ~y the fluid pressure of the mixture in the suppl~ conduit. Thus, the first and second electrical signals overlap for the - fixed time period. A first series of valves responds to the first electrical signal to prevent the flui~
mi~ture from flowing into the first bed of adsorption material and a second series of valves responds to the second electrical signal to prevent the Eluid mixture from ~lowing into the second bed of adsorption ~aterial.

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An outlet condui.t connected to the ~irst and second beds o~ adsorp-tion materials communicates any produc-t fluid produced to a storage chamber. A third valve located in an intermediate conduit connected to the outlet conduit responds to the simultaneous operation of the first and second series of valves caused by the overlap of the first and second electrical signals to provide for pressure equalization between -the first and second beds of aclsorption materials prior to the shift in the fluid mixture between the first and secon~ beds~ With a single pressure transducer con-trolling the communication of the fluid mixture to both the first and second beds of adsorption material, a shift in the trip or actuation point within the transducer in establishing the operational signal ec~ally effect b~th the first and second beds without affect-ing the efficiency of the oxygen separator.
In summary of the a~ove, therefore, the pre-sent invention may be seen to provide i.n a system having first and second valves sequentially operated to communicate a pressurized fluid mixture from a supply conduit to first and second beds of adsorption material, respectively, wherein a product fluid is produced through the re.tention of at least one element in the fluid mixture in the first and second beds, control means for operating the first and second valves comprising:
sensor means responsive to a predetermined rate of adsorptio~ of the element by the adsorption ma-terial for establishing a switching signa].; and controll.er means connected to the sensor means and responsive ko the switching signal for developing first and second siynals for operating the first and second valves to produce ~ ., P~ 5 ~

2~8 the optimum product fluid from each of the first and second ~eds of adsorption material.
- These and other objec-ts should be apparent from reading this specification and viewing the draw-ings.

BRIEF DESCRIPTION OF THE DR~WINGS
Figure 1 is a diagrammatic illustration of a molecular sieve fluid separator system having a pneu- -matically actuated electronic cycle control made accoxd-ina to the principles of this invention;
~igure 2 is a block diagram of the electronic cycle control of Figure l;
Fia~ure 3 is a loaic diagram illustrating the operation of the components in the electronic cycle con-trol; and Figure 4, appearing on the same sheet as Figure 1, is a sec-tional view of a secondary balancing yalve for use with the electronic cycle control for use in the fluid separator system.
DETAILED DESCRIPTION OF THE INVENTION
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The fluid separator system, shown in Figure 1, includes a source of a pressurized fluid mixture which is sequentially supplied to first and second beds 14 and 16 of an adsorption material ~y a pneumatically actuated electronic controller 52 to produce a substan-tially continuous suI~ply of breathable fluid for distri-bu-tion to a recipient.
The source of pressurized fluid mixture is generated from air drawn through a filter 20 by a com-pressor 12. The filter 20 is designed to remove dust, and other airborne particles which may be harmful to operator of the compressor and beds of adsorption ma-terial.

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: To assure that the pressure oF the fluid rnixture does not exceed an unsafe level a pressure relief valYe 28 connected to the supply conduit 24 has a resiliently positionsd poppet 30 that moves away ~rom seat 32 and allows a portion of the fluid mixture to flow to the surrounding environment whenever the ~1uid pressure in the supply conduit exceeds a predetermined pressure leYe1.
To further condition the fluid mixture any heat generated in the compressor 12 is removed by a heat exchanger 26 which consists oF a plurality of fins : that surround the supply conduit 24. The heat exchanger 26 is sized such that the temperature of the pressurized fluid mixture in the supply conduit 24 is no greater than 50F above the surrounding environment.
The supply conduit 24 communicates the flu7d mixture from the compressor 12 to a surge tank 22. The surge tank 22 is connected to tirst and second beds 14 and 16 of adsorption materTal retained in containers 34 and 36~
A first series of valves consisting of a first solenoid valve 38 a first intake valve 40 and a first exhaust valve 42 control the communica~ion of the fluid mixture from the supply conduit 24 into the first bed 14 of adsorption material retained in container 34.
A second series of valves consisting of a second solenoid valYe 44, a second intake valve Lt6 and a second exhaust valve ~8 control the communication of the fluid rnixture from the supply conduit 24 into the seco d bed 16 of adsorption material retained in container 36.
The operation of the first and second solenoid val~es 38 and 44 is controlled through an electrical signal developed in an electronic controller 52 in response to switc~ing signals produced in a first pressure transducer 50.
In more particular detall~ the flrst pressure transducer 50 includes a housing 514 with a pressure chamber 56 created thereln by dtaphragm 58 separating inlet port 60 from atmosphertc ports 62 and 64. A spring 66 connected to wall 68 of the housing 54 urges the diaphragm 58 toward the pressure chamber 56 to hold an electrical contact 7~ on stem 70 away from another e7ectrical contact in switch 74. A lead line 76 connects switch 74 in the first pressure ~ransducer 50 with the electronic controller 52.
The components in the electrontc controller 52 are illustrated in block diagram Form in Figure 2 and respond to a switching signal from swi~çh 74 to control the deYelopmen~ of a ~irst electrical signal ~or operating the first solenoid valve 3~ and a second electrical signal for operating the second solenoid Ya lve 44.
The components in the electronic controller 52 includes a ~irst buffer 78 connected to lead 76 to a delay timer 80~ The delay timer 80 provides an ou~pu~ signal for activating the.balance timer ~2 and an inhibtt timer 84. If the switching signal communlca~ed through lead 76 remains on for a predetermined time period equal to a ~ixed delay tirne of tne delay timer 80, the inhibit timer 84 activates a switch in buffer 78 to inhibi~
the output of buffer 78 and ~hereby protect the system from ~alse triggering when the pressure swi~ch resets from closed ~o opened during sequent al pressurization of the Firs~ and second beds. The. balance timer 82 simultaneously trlggers flip-~low trigger timer 86, a retriggerable 15 second timer 88 in the malfunction warning system, and supplies either buffer 90 or bu~fer 92, dependtng on the operational state of flip-flop 94, with an electrical operational signal.

Bu~fer 90 is designed to respond to the electrical opelatlonal stgnal and supply so1enoid drîver 39 with an operattonal signal, Solenotd drtver 39 in turn supplies solenoid valve 3~ with sufficient electrical current from source 112 to move plunger 94 into coil 96 tn opposition to spring ~7 and tnterrupt the f10w path of atr through port 98 when face 100 on poppet 104 engages seat 102. Thereafter, the pressurtzed fluld mixture ~lows through conduTt 106, past seat 110 and Tnto chambar 108 ~or distribution to the firs~.
intake and exhaust valves 40 and 42 respectively throu~h conduit 113.
Simllarly buf~er 92 Is deslgned to r~spond to the electrtcal operat10nal stgnal and supply solenotd drlver 45 wtth an operattonal stgnal. So1enold drtver 45 in turn supplies solenoid valve 44 with su~Ficlent electrical curren~ From source 112 to move plunger 114 into coi1 116 by overcoming spring 130. Initial movement of plunger 111~ moves ~ace 124 on poppet 1~6 away from seat 128 to al1Ow ~he pressurT~ed flu7d mixture to flow in corldui~
132, 1nto chamber 120~ When pl~nger 114 approaches ~ha center o~ coil 1~6 face 134 on poppet 126 engages seat 136 ~o prevent communTcation of the pressurize fluid mixture from ~he chamber 120 to the atmosphere throu~h port 118 a~d tnittate communicatton from chamber120 through port 122 Tn houstng 138 wlth ~onduit 140 going to the second intake and exhaust valves 48 and 46, respectively.

The first intake valve 40 has a housing 142 connected to the supply conduit 24 by conduit 143 and to the first container by conduit 159. The housing 142 has a first chamber 141~ separated from a second chamber 146 by a diaphra~m 148 A first port 150 in housin~ 142 connects chamber 1~ w;i:h conduTt 143 and a second port 152 connects chamber 146 with condult 113~ A
spring 154 located in chamb~r 146 urges diaphragrn 11~8 toward seat 156 through the co~nunication of th~ pressurized ~luid mixture through chamber 141I to port 1580 Por~ 158 is connected by conduit 159 to port 160 Tn container 34 and in sequence wi~h the speration o~ solenoid valve 44 provides a flow path for the pressurized ~luid mixture to bed 14.
The ~irst exhaust valve 42 has a housing 162 connected to the second con~ainer 36 by conduit 164, to an exhaust conduit 166, and to conduit 113 coming from solenoid valve 38. The housing 162 has a First chamber 167 separatecl from a second chamber 168 by a dlaphragm 170. The first chamber 167 Is connected to condult 164 through port 172 while the second chamber 168 is connected ~o conduit 112 through port 174, A spring 176 located in chamber 167 urges th diaphragm 170 away from seat 178~ When solenoid valve 38 is acti~ated, the fluid mlxture acts on diaphragm 170 to prevent ~ommunication between the ~nterior o~ container 36 and the surrourldlng envTronm~nta however, when solenold valve 44 is ac~ivated, sprtng 176 moves the dtaphra~m 170 aw~y frorn seat 178 ~nd allows ~ree communtcatton between bed 16 and the atmosphere.

The second intake valve 46 has a housing 180 connected to the supply conduit 24, to the second contatner 3G through conduit 184, and to the seeond : solenotd valve 44 through conduit 140. The housin9 180 has a ftrst charnber 186 connec~ed to condutt 140 through port 1~8 and a second chamber 190 ccnnect~d ~8-to supply conduit 12 through port 192, and to conduit 184 through port 194. A diaphragm 196 a-ttached to housing 180 separates the first chamber 186 from the second cham-ber 190 to prevent communication oE the fluid mixture from the supply conduit 24 to the atmosphere ox surround-ing environment through conduit 140. A spring 198 locat-ed in chamber 186 urges the diaphragm 196 toward a seat 200 to inhibit fluid communication between the supply conduit 24 and the conduit 184 connected to container 36.
The second exhaust valve 48 has a hou.sing 202 with a port 206 connected to the first container 34 th.rough conduit 204, a port 208 connected to conduit 140, and a port 210 connected to exhaust conduit 166. A dia-phragm 212 fixed in housing 202 separates a first chamber 21~ associated with port 206 from a second chamber 216 associa-ted with.port 208. A spring 218 in chamber 214 urges diaphraym 212 away from seat 213. When solenoid valve 38 is activated, the fluid mixture acts on dia-phragm 212 to prevent fluid communication between bed 14 and the surrounding environment, however, when solenoid valve 38 is deactivated, spring 218 moves diaphragm 212 away from the seat surrounding port 206 to allow free communication between bed 14 and the surrounding environ-ment through exhaust conduit 166. In addition, when both solenoid valves 38 and 44 are deactivated, springs 176 and 218 move diaphragms 170 and 2].2 away from seats of ports 172 and 206~ respectively to prevent the creation of a vacuum in either heds 14 or 16 which could draw air and any airborne contaminant into con-tainers 34 and 36 which may deteriorate the adsorption material in beds 14 and 16.

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In order to assure that the entire volume of fluid mixture from the supply conduit 24 is pre-sented to the *irst and second beds 14 and 16 of adsorption material end caps 220 and 240 are attached to containers 34 and 36,respectively, through threaded connections 222 and 242 to seal the first and second beds 14 and 16 from the surrounding env;ronment.
End cap 220.has a central opening 224 for connecting a first branch 238 of outlet conduit.244 with the first container 34. A tube 226 which extends from opening 224 to a point adjacent the bottom 248 of bore 247 in container 34 connects outlet branch 238 to a flow distribution chamber 230. A first O ~

retainer 228 is attached to the end of ~ube 226 and wi~h tne container 34 defines the flow distribution chamber 230 adjac~nt end 248. A second re~ainer 234 wh7ch surrounds tu~e 226 is held against bed 14 of adsorp~ion material by a spring 236 to define a f~ow dTs~ribution chamber 237 adjclcent end cap 2~0. Retainers 228 and 234 each have a series of perforations 232 and 233, respect;vely, thereon which retains the particles oF adsorption material in a bed 14 while allowing the product fluid resulting from the ~luid mixture to ~low into tne flow distribution chambers230 and 237. The flow paths through the particles in bed 14 of the molecular sieve or adsorption material reMains substantially constant since spring 23~ continually urges retainer ~34 ~oward retainer 22~ to establish a fixed volume for bed 14. Thus, the density in the bed 14 does not change after repeated cycling and the particles do not de~regate through size changes associatecl with movement oF the particles.
Similarly, the density of the adsorption particles in bed 16 remains substantially constant since spring 250 continually urges retainer 248 ~oward retainer 246. The fluid mixture flows through inlet port 252 in end cap 240 and into ~he flow distribution chamber 251~ for communication ~o ~he partîcles of the adsorption materTal in bed 16 by passing through perfora~ions 256 in retainer 248. A component Tn the fluid mtxture is retained in bed 16 oF ~he 20 adsorptlon materia1 as a product fluid passes through perforations 258 in retainel- 246 into a flow distribution chamber 260. The product fluld from the distribution chamber 260 flows into tube 262 and out port 26~ for distr;bution through the second branch 266 to the outlet conduit 2l~4 going to the supply chamber 267.
The flrst branch 238 and the second branch 266 of the outlet conduit 244 are connected to each other through an intermediate conduit Z68. Fi~st and second valves 270 and 274 located in the intermediate conduit 268 con~rol the communication of breathable Fluld between the first branch 238 and the second branch 266.
The first valve 270 has a housing 276 with a cavlty therein dlvided into a pressure chamber 278, a flow through chamber 280 and a distrtbution chamber 232. A first diaphragm 284 separates the, pressure chamber 278 from tne flow through chamber 280. rhe pressure chamber 278 is connected to conduit Z~L8 112 by a conduît 272 attached to port 288. The flow through chamber 2Bo has a port 290 connected to the intermediate conduit 268 and the distrTbutio~
chamber 282 is connected to the first branch 238 through port 292.
A wall 296 which separates port 290 from port 292 in the flv~ through chamber 280 has an annular seat 298. A spring 300 located in the atmospheric chamber 282 pro~ides a constant force that urges face 294 on poppet 28~
~oward seat 298 to inhibit fluid communication between the ~low through chamber 280 and the ftrst branch 2381 A stem 30~ attached to poppet 286, in ~sponse to a pressure in chamber 278, moves face 294 aw~y from seat 2~ to al~w free communication between conduit 26~ and branch 238.
The second valve 27~ has a housing 304 with a cavity ~herein divided Into a pressure chamber 306, a flow through chamber 3089 and a distribution chamber 310. A first diaphragm 312 separates ~he pressure chamber 306 from the flow throu~h chamber 308. Pressure chamber 306 is connected to conduit 140 by condult 316 attached to port 318. Distr;hution chamber 310 has a port 320 connected ~o ~he second branch 266 and the flow through chamber 30~ is connected to the in~ermedtate condui~ 268 through port 322. A w~ll 324 in the flow through conduit 30~ which separates port 320 from port 322 has an annular seat 326. A spring located 1n the distribution chamber 31~ acts on poppet 31II to ur~e face 330 toward sea-t 326 to prevent f1u7d comrnunicatton between chamb~rs 30~ and 310. Diaphragm 312 is also moved by spring 328 sTnce stem 332 is attached to both diaphragm 312 and poppet 314. Since condu7~ 140 and pressure chamber 306 are connected to the atmosphere through the second solenoic valve 44, sprTng 328 seats face 330 of poppet 314 on seat 326 to prevent fluTd commun~cation between conduit 268 and brar~ch 266 tn the outle~ canduit.
~owever9 branches 238 and 266 o~ the outlet conduit 244 are constan~l~
connected through restricted oriFices 340 and 342 to permlt a portion ~f ~he resultant product fluld produced in the first and second beds 14 and 15 to purge the component from the bed not receiv7ng the Fluld mixture from the 3G supply conduit 24~
The outlet conduit 21~4 is connected to storage container 26~ through an entrance port 344 in cap 346~ A tube 350 which extends through exi~ por-t 348 in cap 346 connects the storage container 267 with a pressure regulator 352. The pressure regulator 352 controls the pressure at whtch ~he produ~t fluid is supplied to the recipient ~hrough condui~ 354.
The pressure regulator 352 has a housing 356. The housing 356 h3s a contro7 chamber 358 connected to a pressure chamber 360 by a passage 362~ A
port 364 conneCts the pressure chamber 360 with conduit 366 at~ache~ to o~tlet port 3lI8 1n the stor~ge container 267. A diaphragm 368 attached to housing 356 separates the control chamber 358 from tne atmosphere. A stem 370 at.ached to diaphragm 368 extends through bearing wall 372 and into pressure chamber 360. A ball 374 which Ts fixed to stem 370 and urged toward seat 376 by a spring 378. However, spring 380 acts on diaphragm 368 to urge ball 374 away from saat 376. As the pressure tn the pressure chamber 358 builds up, spr;ng 380 is overcome and ball 374 is urged against seat 376 ~o interrupt ~he fl~w of produc~ fluid into passage 362. HousTng 356 also has port 3~2 which connects passage 362 with a filter 384 in the supply conduit 354. Element 386 in filter 384 is designed to rernove harmful bacterla ~hat may be carried by the produ~t fluido In addition, a ~10w selector 3~ has a pluralTty of different orifices 390, 392, 394, 396 which control ~he rate of flow oF the prodwct fluid from the supply conduit 354 to provide ~he recipient with a produc~ fluid at a constant pressure.
In order to check the operation oF the operation of the first and secand beds 16 and 18, the pressure oF the product fluid is continual1y monitored through the use of a second pressure transducer 400. The second pressure transducer 400 has a housing 402 with a pressure chamber 404 connec~ed ~y coI~du~t 406 to the outlet condu;t 244 through port 408. A dlaphragm 410 separates pressure chamber 404 from an atmospheric chamber 412 to allow spring 4lLl to hold a contact on stem 416 away from a contact in electrical switc~
418. Switch 418 is connected to electronic controller 52 by lead 1I20. As shown in figure 2, lead 420 is connected to a buffer 422. Buf~er 422 amplifies any failure signal from switch 41~ and provides an indica~or 424 such as a bell~ light, buzzer, etc. , with an actuation signal of a low pressure or failure oondition present in the breathiny s~/stem 18. In addition if the retriggerable timer 88 if allowed to "time out" also signals a malfuncsi~n in the oxygen separator, In this condition, either one or the other bed 14 and 16 is taking too long a time to pressurize and thereafter the timer ~8 supplies buffer 422 with a failure signal. This failure signal in turn ~lso operates indicator 424.

MODE OF OPERATION OF THE INVENTION

The fluid separator system 18, shown in Figure 1, is placed i~
an operational condi~ion upon closure of swith 426 to supply compresso~ 12 and electronic controller 52 with electrical energy from source 1120 Fllp-flop 94 is either supplying buffer 90 or buffer 92 with an electrical operational signal, therefore, even upon initial actuation either solenoid valve 38 or 41I is being supplied with electrical energy. For illustrative purposes 3ssume the electrical si~nal from flip-flop 94 is being communicated to buffer 30.
Thus, the first solenoid valve 3~ is supplTed with a first electrical er~argy signal suf~icient ~o move plunger 94 into coll 90 and position Face 100 ~n seat 102 to prevent communTcation between chamber 105 and the surrounding environment.
At the same time compressor 12 is drawing air from the environment and pressuri~ing the same to produce a pressurized fluid mixture tnat is communicated to the supply conduit 24 and surge tank 22. The pressurized fluid mixture in the supply conduit 24 is simultaneously transmitted to ~he first intake valve 40, and first exhaust valve 42 through the condui~s 106, chamber 105, and conduit 113.

The ~orce o~ ~he pr~ssuri~ed fluid mixture Tn chamber 146 of the first intake valve 40 is combined with spring 154 and acts on diaphragm 148 to seal seat 156 to prevent the communicatton of pressurized fluid mixtur~
through port 1500 At the same tTme, the pressurized fluid mlxture in cha~ber 163 of the first intake valve 42 overcomes spring 176 to urge diaphragm 170 against seat 178 and prevent fluid communication from bed 16 ~o the atmo~phere through port 172.

tn addition, the pressurized fluid mixture Tn conduit 113 ~s communicated through canduit 272 to chamber 278 of first valve 270. The pressurized Fluid mixture in chamber 278 acts on diaphraym 284 to move face 294 of poppet 286 away from seat 298 and allow fluid communication from intermediatc conduit 268 to the first hranch 238.
At the same time, since the second solenoid valve 44 is de-energized and spring 130 moves face 124 on poppei 126 fixed to plunger 114 against seat 128 to prevent the communication of the pressurized fluid mixture through port 129. In this condition, spring 218 in the second exhaust valve 48 moves diaphragm 212 away from the seat of port 206 and allows free communication of bed 14 in first container 34 with the atmosphere through exhaust conduit 166. However, spring 328 in the second valve 274 moves face 330 of poppet 3?4 against seat 326 to prevent communication from the second branch 266 of the outlet conduit 244 to the intermediate conduit 268, Thereafter, the pressurized fluid mixture in the supply conduit 24 flows past seat 196 in the second inlet valve 46 and into the second bed lG
of adsorption material by way of conduit 184 and flow distribution cnamber 254. The fluid mixture passes through the particles of adsorption material in the second bed 16 where a component or components are adsorbed as a product fluid passes into flow distribution chamber 260. The product fluid flows from distribution chamber 260 tnrough tube 262 and into the second branch 266 fo; distribwtion through outlet conduit 244 to the supply container ~66.
At tne same time a portion of the product fluid in outlet conduit 244 flows past restriction 340 and through the first branch 238 to flow distribution chamber 230. The pressurized product fluid flows past retainer 228 and through the particles of adsorption material in bed 14 where the reta7ned component or components are desorbed from the particles and carried to the atmosphere after passing through distributiorl chamber 237, port 160 in end cap 220, conduit 204, exhaust valve 48 and exhaus~ conduit 166, To reduce any noise that may occur tn the cornmunicatlon of the purge mixture to the environment, a muffler 428 is at:tached to the end of the exhaust conduit 166.

As more of the component or components in the ~luid mixture afe retatned by the particles of adsorption material in bed 16, the fIuid pressure in the supply conduit 24 builds up and follows a curve as illustrated on curve 430 in Figure 3. The tncrease in the fluid pressure in the supply condult 24 is communicated ~o chamber 56 in the first transducer 50. When the fluid pressure reaches a predetermined pressure leYel as illustrated by point 432~
spring 66 is overcome and diaphragm 58 moves contact on s~em 66 into eng~gement with electrical contact on switch 74.
WitIl the closure of switch 74 an electrical signal is carried on ]o lead 76 to buffer 78. The electrical signal when received by buffer 7~ chan~es the logic state of ~he buffer 78 from high to low as illustrated by line 431J inFlgure 3. The ~elay timer 80 is triggered by the buffer 78 for a predetermined time period, illustrated by the interval between points 436 and 43~ in line 440 in Figure 3. I~hen the delay ~imer 80 "times ou~", illus~rated by se~tion 434 Ofcurve44li, a triyger signal is communicated to the one second timer 82 and inhibit timer 84. The inhibit timer 84 follows a curve iliustrated by line 446 and after the time period Interval between points 436 and 438 prevents the buffer 78 from being cycled until a time perisd equal the time ;nterval between points 41~ and 450 has p~ssed.
At the same time timer 82 suppltes buffer 92 with a transfer electrical sign31 for a time period equal to the ;nterval between points 452 and 454 on .;
curve 456. At point 454, timer 82 initTates actuation of flip-flop trigger 86 and reset timer 8~.
When buffer 92 receives the transfer electrical signal from timer 82, a second electrical signal flows from buffer 92. The second electrical signal has an amplitude tllustrated by point 458 in curvs 460 in Figure 3~
The second electrical signal is transrn1tted to solenoid driver 1~5 which in turn energizes coil 116 in the second solenoid valve 1~4 for a time period illus~rated by the time interval between point 462 and 1~64 on curve-466.
With coil 116 energized, plunger 114 moves to the center of coll 116 and urges face 134 onto seat 136 to interrupt comrnunication of chamber z~

120 with the surrounding environment through port 118, Thereafter, fluid mTxture in the supply condui~ 24 flows into conduit 140 and acts on diaphragm 196 in the second intake valve 46 and seats dtaphragm 196 on sea~ 200 t~
inhlbit the ~low of the fluid mlx~ure through inlet port 192 of the second intake valve 46. A~ the same time, th7s fluid mix~ure flows into chamb~r 216 of the second exhaust valve 4~ and urges dlaphragm 212 a~ainst the seat o~
port 206 to interrupt ~lu;d eommun;cation ~rom bed 14 to ~he atmosphere throu~h exhaust conduit 166. In a~ditTon, thls same fluid m1xture f10ws in~o chamber 306 of the second va1ve 274 and acts orI dTaphragm 312 to move f~ce 33~ on poppet 31l1 away from seat 326 and open fluid commwnicatton between the inter~
me~late condui~ 268 and th~ second branch 2660 Since solenold valve 3g is stlll energlzed, the pressurlzed flu;d mlxture still holds face 294 of the ~irst valve 270 away from seat 298 to allow free communication between branches 238 and 266 an~ allow the fluid pressure In the ~irst and second beds 1l~ and 16 to equal1za during the simul~aneous actuation of the ~irst and second solenold valves 3~ and 44.
At the end of the time Interval illustrated between points 452 and ~I54 on llne 456, flip-flop trlg~er timer ~,transmits a spilce signal 468 illustrated by curve442 tn Figure 3 to fltp-flop 94. Th~.reafter, the eleç~ricalo stgnal from flip-flop 94 switches from buffer ~0 to buffer 92 to sustain the amplltude of the se~cond electrical slgnal 458 from buffer 90. At the same time, the output from buffer 90 i5 reduced to z~ro as illustrated by point 470 on curvelI72. With the electrlcal signal from buffer 90 interrupted, coil 96 of solenoid valve 38 is deanerglzed and Follows a curve 711ustra~ed ~y ~ine 474 in Figure 3J
During ~he tTme interval illustrated between points 452 and 454, the fluid pressure In the supply conduit 2'i and surge tank 22, builds up to ~o point 476. When coil 96 o~ solenoid valve 3n is deenergtzed~ spring 97 ~oves face 103 on plunger 94 against seat 110 to tnterrupt commwnic~tlon From sup.p1y conduit 24 through conduit lOG. Thereafter, sprlng 176 In the first exh3ust valve 42 moves diaphragm 170 away from seat 178 to initiate communication of bed 16 to the atmospnere ~1rough flow dis~ribution chamber 254 and exha~st conduit 16G.
Thereafter, the pressure of the fluid mixture acts on diaphragm lL18 in the first inlet va~ve 40 to allow the fluid mi~cture to flow past seat 156 for distribution to the first bed 14 of adsorption material. A
component or components is retained in bed 14 as a product fluid passes into flow distribution chamber 230 for transmtssion to the outlet conduit 244 through branch 238.
Initial communication of the product breathable fluid mixture from 10 the supply concluit 24 causes a reduction in the fluid pressure in concluit 24 as illustrated by point 478 on curve430. Thereafter~ as the component or components are retained in the particles of adsorption material in bed 14, the fluid pressure in the supply conduit 2lI again starts to increase and when the pressure equals thae illustrated by point 432'~ the pressure transducer 52 again activa~es switch 74 to initiate the transfer of the supply of fluid mixture to i~ed 16. Thereafter, the one second timer 82 supplies buffer 90 with an electrical signal as illustrated by point 471 oncurve472 ;n Figure ~r

3. Thus, so1enoicd 38 is supplied with electrica1 current for a lime interval illustrated by points l~73 and 475 on curve474 in Figure 3. As seen in Figure 20 3, the solenoid va1ves 38 and 44 are simultaneously energi~ecl to again allo~valves 270 and 274 to operate and permit the pressures in beds 14 ancl 16 to equalize before the fluid mixture in the supply conciuit 24 is sequential1y transferred. This cycling continues as long as the breathing system 18 is in operation.
In an effort to reduce the number of components in breathing system 1~, valves 270 and 274 ir, the intermedia~e conduit 268 were replaced by a single valve 500 illustrated in Figure 4, The single val~re 500 has a housin~ 502 wl~h a pressure chamber ~04 directly connec~ed to the supply concluit 24 by conduit 506 and a flow through 3~ chamber 507 connected to branch 238 of the outlet concluit 24lI by conclui~ 5B8 and to branch 266 by conduit 510. A wall 512 separates the port 514 from port 516 whil~ diaphragm 518 separates the pressure chamber 50l~ frorn an atmo~pheric chamber 519. A stem 520 a~tached to diaphragm 518 ex~ends through wal 1 513.
A poppet 522 attacr,ed to stçm 520 is located in chamber 506. A sprin~ 5~3 connected to wall 513 urges poppet 522 against seat 524 to prevent fluid communication between the first branch 238 and the second branch 266 thrDugh the intermediate conduit, Thereafter during a cycle of operation when switch 52 is activated at pressure 432, and the solenoid valves 33 and 44 are simultaneously activated, spring 522 is overccmc by the pressure build-up in the supply conduit 24. Fluid communication exists between the first branch 23g and ~he second branch 266 during the time period that the pressure increases from point 433 to point 476. Thereafter, when the electronic controller 52 s~ltches the communication of the supply of fluid mixture between the first and second beds 14 and 16, the pressure in the supply conduit drops to point 47e, thereafteI-~ spring 523 urges poppet 522 onto seat 524 to interrupt communication between the ~irst and second branches 238 ar,d 266 and allows ~he product fluicI
:` to flow to the storage container 267, Thus~ the transfer of the operational communication of the fluid mixture is dependent on the fluid pressure developed in the supply conduit 24. However, if the operational time period that either beds 14 or 16 exceeds a predetermined time period as estab1ished by timer 88, a siynal is transmitted to buffer 422 and malfunction indicator 424 is activated to inform an operator of a potential ~ailure condition in the breathing system 18.
It should be noted that the extraction system 18 can be utilized to produce either oxy9en or nitrogen as the product Fluid simply by changing ~he type of adsorption material in beds 14 and 16.
In addition the adsorptlon material in beds 14 and 16 can be seleeted to remove water prior to the retentior, of the adsorable COMpOnent. In this case a screen 15 and 17 are placed 7n beds 14 and 16 ~o separate material ~
from material B. Thus, the adsorption material under such conditions is always presented as a dry fluid mixture and the possibi1ity of deterioratiorI oF the adsorption material further reduced.

Claims (25)

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

1. In a breathing system wherein a breathable fluid is separated from a source of fluid mixture through the retention of at least one element in the fluid mixture by an adsorption material located in first and second chambers, control means for regulating the sequential communication of the fluid mixture to the first and second chambers comprising:
a supply conduit for communicating the fluid mixture from the source to said first and second chambers, the pressure of the fluid mixture in said supply conduit varying with the rate of flow and adsorption of the element of the fluid mixture in said first and second chambers;
first transducer means connected to said supply conduit and responsive to a predetermined fluid pressure in the fluid mixture for establishing a switching signal;
electronic means connected to said first trans-ducer means and responsive to said switching signal for sequentially developing a first electrical signal and a second electrical signal, said electronic means permitting said first and second electrical signals to overlap for a predetermined time period;
first valve means connected to said supply con-duit and responsive to said first electrical signal for preventing communication of the fluid mixture to the first chamber and allowing communication of the fluid mixture to the second chamber during a first mode in a cycle of operation; and second valve means connected to said supply con-duit and responsive to said second electrical signal for preventing communication of the fluid mixture to the second chamber and allowing communication of fluid to the first chamber during a second mode in a cycle of operation, said overlap of the communication of the first and second electrical signals allowing the fluid pressure of the fluid mixture in the first and second chambers to equalize before proceeding to the first and second modes in a cycle of operation.

2. In the breathing system, as recited in claim 1, further including:
an outlet conduit having a first branch connect-ed to said first chamber and a second branch connected to said second chamber for communicating the breathable fluid to a storage container;
second transducer means connected to said out-let conduit for generating a failure signal corresponding to a predetermined minimum fluid pressure in the breath-able fluid; and an indicator connected to said second transducer, said failure signal activating said indicator to inform an operator of said minimum fluid pressure con-dition in the breathable fluid.

3. In the breathing system, as recited in claim 2, wherein said electronic means includes:
switch means connected to said indicator for resetting said indicator with a shift in operation be-tween the first and second modes of operation to nullify the failure signal with an increase in the fluid pressure of the breathable fluid above the minimum fluid pressure.

4. In the breathing system, as recited in claim 2, further including:
an intermediate conduit for connecting said first branch with said second branch of the outlet conduit; and third valve means located in said intermediate conduit and connected to said supply conduit, said third valve means being responsive to the pressure of the fluid mixture in said supply conduit during the simul-taneous operation of said first and second valve means for allowing unrestricted communication between the first and second chambers.

5. In the breathing system, as recited in claim 4, wherein said third valve means includes:
a housing having a cavity therein with a first port connected to said first branch, a second port connect-ed to said second branch, and a third port connected to said supply conduit;
wall means for separating said third port from the first and second ports to establish a pressure chamber within said cavity; and resilient means connected to said housing for urging said wall means toward one of said first and second ports to prevent fluid communication through the intermediate conduit, the fluid pressure in the supply conduit during the simultaneous operation of the first and second valves overcoming the resilient means and moving said wall means away from said one of the first and second ports to permit the fluid pressure of the fluid mixture to equalize in the first and second chambers.

6. In the breathing system, as recited in claim 4, wherein said first valve means includes:
a first solenoid valve connected to said electronic means for regulating the communication of a first pressure signal in response to said first electrical signal;
a first exhaust valve connected to said first chamber and responsive to said first pressure signal for communicating the first chamber with the surrounding environment; and a first intake valve connected to said supply conduit and responsive to said first pressure signal for preventing the flow of the pressurized fluid mixture from said supply conduit into said first chamber of adsorption material.

7. In the breathing system, as recited in claim 6, wherein said second valve means includes:
a second solenoid valve connected to said electronic means for regulating the communication of a second pressure signal in response to said second electrical signal;
a second exhaust valve connected to said second chamber and responsive to said second pressure signal for communicating the second chamber with the surrounding environment; and a second intake valve connected to said supply conduit and responsive to said second pressure signal for preventing the flow of the pressurized fluid mixture from said supply conduit into said second chamber of adsorption material.

8, In the breathing system, as recited in claim 7, wherein said third valve means includes:
a housing having a cavity therein with a first port connected to receive said first pressure signal from said first solenoid valve, a second port connected to receive said second pressure signal from said second solenoid valve, a third port connected to said first branch of the intermediate conduit, and a fourth port connected to said second branch of the intermediate conduit;
first equalizer valve means located in said cavity for limiting the communication of said first pressure signal to a first chamber adjacent said first port;
first resilient means for urging said first equalizer valve means toward a first seat to prevent communication from the cavity to the first branch through said third port;
second equalizer valve means located in said cavity for limiting the communication of said second pressure signal to a second chamber adjacent said second port; and second resilient means for urging said second equalizer valve means toward a second seat to prevent communication from the cavity to the second branch through said fourth port, said simultaneous communication of the first and second pressure signals to the first and second chambers moving said first and second equalizer valve away from said third and fourth ports to allow unrestricted fluid communication through said cavity to permit said pressure equalization to be achieved in said first and second chambers.

9. In the breathing system, as recited in claim 8, wherein said electronic means includes:
timer means for inhibiting said switching signal for a predetermined time period to prevent the creation of a false switching signal caused by a resetting of said first transducer means by the fluid pressure of the fluid mixture in the supply conduit.

10. In the breathing system as recited in claim 2 further including:
a first restriction located in said first branch; and a second restriction located in said second branch, said first and second restrictions causing a back pressure to develop in said bed of adsorption material receiving the fluid mixture to con-trol the rate of adsorption of the component in the fluid mixture.

11. A fluid separator system comprising:
a source of fluid mixture under pressure;
a first container having a first chamber therein for retaining a quantity of adsorption material, said first chamber having a first port and a second port;
a second container having a second chamber therein for retaining a quantity of adsorption material, said second chamber having a third port and a fourth port;
a supply conduit for connecting said source of fluid mixture with said first and third ports, the fluid pressure in said supply conduit being a function of the rate of flow of said source of fluid mixture through said first and second chambers and rate of adsorption of an element in said fluid mixture by the adsorption material;
first transducer means connected to said supply conduit and responsive to a predetermined pressure of the fluid mixture in said supply conduit for developing a switching signal;
electronic means connected to said transducer means and responsive to said switching signal for sequent-ially developing first and second electrical signal, said first and second electrical signals overlaping for a pre-determined time period;
first valve means connected to said supply con-duit and said electronic means, said first valve means being responsive to said first electrical signal for preventing the communication of the pressurized fluid mixture through said first port while allowing communication of the fluid mixture through said third port, said fluid mixture flow-ing through said third port and into said second chamber where at least one element of the fluid mixture is re-tained by the adsorption material to produce a product fluid during a first mode in a cycle of operation;
second valve means connected to said supply conduit and said electronic means, said second valve means being responsive to said second electrical signal for preventing the communication of the pressurized fluid mixture through said third port while allowing communication of the fluid mixture through said first port, said fluid mixture flowing through said first port and into said first chamber where at least one element of the fluid mixture is retained by the adsorption material to produce a product fluid during a second mode in a cycle of operation; and an outlet conduit having a first branch connected to said second port and a second branch connected to said fourth port, said product fluid flowing through said outlet conduit to a storage container, a portion of said product fluid flowing through said first branch past said second port and into said first chamber for purging the adsorption material of any retained element during said first mode of a cycle of operation and through said second branch past said fourth port and into said second chamber for purging the adsorption material of any retained element during said second mode of a cycle of operation, said overlaping of the first and second electrical signals simultaneously operating said first and second valve means to prevent the flow of the fluid mixture to the first and second chamber while allowing pressure equalization in the first and second chamber through the communication of said second and fourth ports with said outlet conduit.

12. The fluid separator system, as recited in claim 11, further including:
second transducer means connected to said outlet conduit and responsive to a minimum fluid pressure of the product fluid for developing a low pressure warning signal; and indicator means connected to said second transducer means and responsive to said warning signal for informing an operator of a minimum fluid pressure condition in the product fluid.

13. The fluid separator system, as recited in claim 12, wherein said electronic means includes:
timer means connected to said indicator means and responsive to said switching signal from said first transducer means to inform an operator whenever the first and second electrical signals which operate the first and second valves, respectively, exceeds a preset time.

14. The fluid separator system, as recited in claim 11, further including:
a housing having a cavity with a first pressure port connected to said first valve means, a second pressure port connected to said second valve means, a first flow through port connected to the first branch of the outlet conduit, and a second flow through port connected to the second branch of the outlet conduit;
a first diaphragm means fixed to said housing for defining a first pressure chamber adjacent said first press-ure port, said first diaphragm responding to the operation of said first valve means to only allow fluid communication from the cavity to said first branch;
and a second diaphragm means fixed to said housing for defining a second pressure chamber adjacent said second pressure port, said second diaphragm means responding to the operation of said second valve means to only allow fluid communications from said cavity to the second branch, said first and second diaphragm means responding to the simultaneous operation of said first and second valve to allow communication between said first and second branches of the outlet conduit through said cavity and thereby per-mit the fluid pressure in the first and second chambers to equalize.

15. The fluid separator system, as recited in claim 14, further including:
a first tube extending from said second port in said first container through said quantity of adsorption material retained therein;

a first retainer attached to said first tube and cooperating with said first container to establish a first distribution chamber within said chamber adjacent the end of said tube;
a second retainer surrounding said tube and cooperating with said first container to establish the volumetric limits for a first bed of adsorption material;

a first cap attached to said first container for sealing said first container from the surrounding environment; and a first spring connected to said first cap for urging said second retainer toward said first retainer to place a uniform force on said first bed of adsorption material and thereby maintain substantially the same density of the adsorption material after repeated cycles of operation.

16, The fluid separator system, as recited in claim 15, further including:
a second tube extending from said fourth port in said second container through said quantity of adsorption material retained therein;
a third retainer attached to said second tube and cooperating with said second container to establish a third distribution chamber within said second chamber adjacent the end of said second tube;
a fourth retainer surrounding said second tube and cooperating with said second container to establish the volumetric limits for a second bed of adsorption material;
a second cap attached to said second container for sealing said second container from the surrounding environment; and a second spring connected to said second cap for urging said fourth retainer toward said third retainer to place a uniform force on said second bed of adsorption material and thereby maintain substantially the same density of the adsorption material after repeated cycles of operation.

17. The fluid separator system, as recited in claim 11, further including:
a first screen located in said first chamber; and a second screen located in said second chamber, said first and second screens separating a first adsorption material from a second adsorption material, said first adsorption material removing moisture from said fluid mixture to produce a dry fluid mixture to the second adsorption material where the element is removed to product the product fluid.

18. The fluid separator, as recited in claim 17, further including:
a filter located in said outlet conduit for removing any air borne bacteria from the product fluid that could harm a recipient of the product fluid.

19. In a system having first and second valves sequentially operated to communicate a pressurized fluid mixture from a supply conduit to first and second beds of adsorption material, respectively, wherein a product fluid is produced through the retention of at least one element in the fluid mixture in the first and second beds, control means for operating said first and second valves comprising:
sensor means responsive to a predetermined rate of adsorption of the element by said adsorption material for establishing a switching signal; and controller means connected to said sensor means and responsive to said switching signal for developing first and second signals for operating said first and second valves to produce the optimum product fluid from each of the first and second beds of adsorption material.

20. In a system having first and second valves sequentially operated to communicate a pressurized fluid mixture from a supply conduit to first and second beds of adsorption material, respectively, wherein a substantially identical product fluid is produced through the retention of at least one element in the fluid mixture in the first and second beds, said first and second beds being connect-ed to an outlet conduit for distributing the product fluid control means for operating said first and second valves comprising:
a single sensor located in said supply conduit and responsive to a predetermined change in the fluid pressure of the fluid mixture caused by the adsorption of the element by said adsorption material for establish-ing a switching signal; and electronic means connected to said sensor and responsive to said switching signal for developing first and second signals for sequentially operating said first and second valves, said first and second signals over-lapping for a predetermined time period to allow the fluid pressure in the first and second beds to equalize before the fluid mixture is presented thereto.

21. In the system recited in claim 20 further including:
an indicator in the outlet conduit for informing an operator of a minimum fluid pressure in the product fluid.

22. In the system recited in claim 21 further in-cluding:
switch means connected to said indicator for resetting said indicator with an increase in the fluid pressure of the product fluid resulting from a shift in the communication of the fluid mixture from one of the first and second beds to the other.

23. In the system recited in claim 22 further in-cluding:
timer means for inhibiting said switching signal for a predetermined time period to prevent the creation of a false switching signal caused by pulsations in the fluid pressure of the fluid mixture in the supply conduit.

24. In a system having first and second valves sequentially operated by a control to communicate a pressurized fluid mixture from a supply conduit to first and second beds of adsorption material, respectively, wherein a substantially identical product fluid is pro-duced through the retention of at least one element in the fluid mixture in the first and second beds, said product fluid being communicated from the first and second beds by an outlet conduit, the improvement comprising:
a single sensor located in said supply conduit and responsive to the change in the fluid pressure caused by the sequential adsorption of the element by said adsorption material in said first and second beds for establishing a substantially identical switching signal;
means for inhibiting said switching signal to prevent the creation of a false switching signal caused by pressure surges in the fluid pressure of the fluid mixture; and electronic means connected to said sensor and responsive to said switching signal for operating said first and second valves to assure that the product fluid is substantially the same consistency at all times.

25. In the system, as recited in claim 24 further including:
an indicator in the outlet conduit to inform an operator of the pressure of at least a minimum fluid pressure in the product fluid.