US2620740A - Valve - Google Patents

Description

Dec- *957771952 H. u. GARRETT ET AL VALVE 2 SHEETS-SHEET l Filled-sept. 24, 1949 /4 TTOH/VEKS Dec. 9, 1952 H. U. GARRl-:TT ET AL 2,620,740

` VALVE Filed Sept. 24. 1949 2 SHEETS- SHEET 2 sa V l 34 Henry U. Garre C`//ffor0 M Peers INVENTORJ ATTORNEYS 3, ing in section one of the valves of the Fig. 1 system and illustrating an embodiment of this invention,

Fig. 3 is a View similar to Fig. 2, but executed upon a still larger scale, and illustrating the valve or" Fig. 2 with the valve member in open position,

Fig. 4 is a view taken along the lines 4 4 in Fig. 3 in the direction of the arrows,

Fig. 5 is a view taken along the lines 5--5 in Fig. 3 in the direction of the arrows, and

Fig. 6 is a view taken along the lines 6 5 in Fig. 3 in the direction of the arrows.

Referring to the drawings and more particularly to Fig. 1, the well bore is shown to be equipped with a string of casing 'I and a flow string of tubing 8 which at its lower end may be equiped with a well screen 9. A seal is provided between these strings of well pipe by the packer I5 adjacent the lower end of the well bore. At the ground surface ya seal is provided by the usual wellhead equipment between the two strings of well pipe and the inner string or flow string connects with a flow fitting I I while a fitting I2 is connected with the interior of the casing for supplying a lifting fluid or pressure fluid thereto.

The flow string of tubing isvequipped with a series of valves I3 for admitting this pressure uid into the interior of the flow pipe at preselected levels therein. It is to be understood that the arrangement of these Valves relative to the two strings of pipe may be reversed so that the pressure fluid is introduced into pipe II and the well uids will be produced through the pipe I2. The pilot operated valve of this invention is especially adapted for this type installation for it-will permit charge of large Volumes of gas into the tubing-casing annulus. However, the arrangement shown in the drawings is the preferred arrangement in most instances.

v The individual valve I3 may all be of the same type and construction and may all have a pressure responsive motor with the same resilient element for controlling opening and closing of the valve. The preferred embodiment of the valves I3 is illustrated in Figs. 2 to 6 inclusive.

VReferring to Fig. 2, it will be seen that the entire valve may be enclosed in a single housing made up of several inter-connecting parts. The upper portion of the housing may be considered as `enclosing a pressure responsive motor for controlling a valve which controls a passage communicating between the interior of the tubing string 3 and the annulus between the tubing string and casing. This valve and passage may be utilized to charge lifting gas or fiuid directly into the tubing or may be primarily for the purpose of providing a pilot operation for governing the opening and closing of `a second valve controlled passage, which may be of large crosssectional area, to accommodate the injection of large volumes of gas into the iiow conduit.

Referring in detail to the drawings, the portion of the housing enclosing the motor includes va nipple I flto which is attached a cap I5 at its upper end and a fitting I6 at its lower end. Within the cap I5 is housed a resilient element which may be -a bellows II providing a sealed chamber within the cap which may be charged, at least in part with compressible iiuid under pressure. The lower end of the bellows may be sealingly secured to the upper surface of nipple I4 and the upper end of the cap may include a tting for charging pressurev fluid into the presproviding a chamber 25 within a fitting 3| sesure dome, this tting being shown schematically at I8 in the interest of simplicity.

The upper end of the bellows is sealed oi by a head piece I9. The head piece I9 may carry a washer 2Q secured thereto by screw 2| and the washer is adapted to engage the underside of an apertured partition 22 carried` interiorly of the cap. This engagement limits upward movement of the head piece or part I9 and the washer provides ya seal between the partition and the head piece. If desired, an incompressible fluid, such as water, may ll the space between the bellows and the cap below the apertured partition 22 but the level of liquid will be just above the apertured partition so as to leave ample volume for a compressible fluid, as gas, to provide for reciprocation of the head piece or part I9 under the inuence of pressure differential thereacross. This liquid provides an incompressible backing, when the washer seals between the head piece and the partition 22, to prevent a build up of pressure interiorly of the bellows from distorting it to the point of rupture,

It will be seen that the head piece IQ may be considered as a motor part which is adapted to be actuated by the force of pressure within the pressure dome acting against its upper surface urging the part in a direction to collapse the bellows and the forces transmitted to the head piece opposing the force of the resilient element or pressure dome. The tting I5 has a plurality of openings Ia allowing access of pressure fluid in the tubing-casing annulus to the bellows, which acts against an area or surface of the head piece to urge it in a direction opposing the force due to the pressure within the pressure dome. However, it is seen that the head piece is connected and may be integral with a stem 23 which extends through an axial bore in fitting IIS and has a sliding seal therewith. This sliding seal may be eiected by an O-ring 24 ina groove in the periphery of stern 23. Thus, the area against which the pressure exteriorly of the housing acts against to urge the stem and part I9 in the direction opposing the resilient element is equal to the annular area within the sealed connection of the bellows to the head piece less the area of the periphery of stem 23 at the seal provided by the O-ring.

In order that the motor may be 'responsive to both the pressure of the gas to be chargedfrom one container into the other and the pressureV within the latter container, provision is made t0 expose a surface to the pressure within the latter container in such manner that the force of this pressure acting against this surface may be transmitted to the motor part so as to oppose the resilient element. This may be accomplished by housing and may be secured, as by welding, to the tubing. O-rings or the like seal between the valve housing and coupling on each side of the space 26.

This annular space 25 communicates through aY port 28 with the interior of the tubing. This outlet port may have a screen 29 across it to p-revent debris from entering into the space 2t and cham- Vvber 25.

The chamber 25 will be seen to communicatel aecomo I.through port 3 lb with the exterior of the-valve housing". This port maybecontrolled by :azvalve member 30 carried at theflowerendlof stemj. The total crosssectional area of` port 3 lfb isconsiderably less than the area. across sternv 23r.at'the AOgring 24 so that there'is a,substantial-fareagexposedY to the pressure `within lchamber S25 ceven vwhen the valve `is seated. vl The passage between the interiorofchamber -25 and 'the exteriory of kthe .valve'housi'ng' is'con.4

stricted relative tothe passage vbetween Vchamber 25 andthe interior or the'-flow-'stringr of tubing f8.. Thus, with the Valvemember130'open,the-pressure within chamber"25 willstill be..substantially that within the tubing string for most'of the pres sure dropf'w-ill occur across the constrictiong 'f It'-isjcontemplated that the mechanism thusffar disclosed vmay be considered as constituting a complete valve for charging. perssure fluid into `the tubing V8. In this case,` the-'openingilb orinletl tdv chamber 25 andl theoutlet port- 28 serves -to pas" alln of the huid' to be charged into"'the"` tubins- L;Y l

'In many Vinstallations,@it is desired to 'have lrather"large port openings for injectingY pressure HuidY intof'the container to'V becharge'd.V Also', little spaceis available toA accommodate large valve mechanisms, andfit is therefore desirable to maintain 4the actuating mechanism for/the valve as small" as possible. For this reason,4 it is'- preferred in'.tiiesefinsta11ations,to utilize the portion of the valvrnechanism just'-described primarilvas a pilotvalvior'controlling opening and closing of a second valve in resp'onseto the pressure of the ii'uidtobe charged and the pressure Within thecmtainer into which the'. sind is tplbeinjected.

To accomplish this, there'is-secured-to-the lower .d

end" of tting? 3l acylindrical sleeve 32'nha'vin'g 'a piuraiityfoflpoftsfss communicating wthanan;

'maar .hallbe'r niereflyfof coeplinef which -'surrounds'the-valve housing-and is s'ecnredto the tubingbyrweldingor thelike. Seal-s areprovide' between n the Wcoupling and the housing nboth Sides Of. the? Cb'lmbe1`34fSl1P-asoiflgsas ShQWn* LThe coupling 35 hasa major outletfopening or port g j 36 registering with .port 3T rin fthe j tubing string, The passage provided by the ports 3 6 and A,3 1 .may be protected'byVagscreen `to prevent pas; Asage of `debris..from.interior-of thetubing string 'Bj' into the internalmechanism ofv thervalve inthe 'eventxthe ,pressure withinjthe tubing/should fex- 'ceedthe pressurewithin the valve atany time.

frneports. 3.6. andai. aswenias there@ ra'f' thea-ports 33g, Vmay be constructedso astolirovide alare@ urnes offri-luid to be .injected intotheytubing These portsareI connected toa major .inletv open:

passa-ge for accommodation-of large'vol'f j arid'hence wth@ exterior-ofthe musing-brie passage which includesthe interior pillow piece 3 9. Y This iiow piece may carry a' Part 4l) tofwhich a screen 1 having many perforation; may be rattacheid; as .Shownlat 4 l A Beati-ring. mythe h'eljd Aagainst'a shoulder 4,3, extending interiorly oi 'fitting 39, by Ypart 40,v against which ball valve rnember44v isadapted to seatto prevent ii'owof fluid. from A interiorly ofthe conduit into the cas'- fing-tubing annulus. Y d, 'I .The seconda valvezbfo'r.controllingiiowjoruid to be injected into the-tubing s is -shownat 45 and ist adapted fio seat. against 'the vereren@ `0f flew piecev 39'., Major valve yelement or member 45=is secured to a :cylindrical guide partV 46 Ywhich has al'sliding seal within al reduced diameter,punition of thebore in sleeve 32. This seal may be provided br the O-ring'41- in the-peripheral groove of cylin- 6. drical partl. Thus, 'the interior: ofxthezcylindri'- cal f sleeve 132* is ydivided. into ytwo i chambers which are' sealingly' separated .and wththe valve-mem'- berv 45 'closedpthe' lower `of these chambers communicates onlywith the interior of tubingstring 8whi1e theupper of thesechambers communicates with Athe exterior ofjthe housing through a passageV which may be provided centrally of the vvalve 4.5, the part 46. andthe' guide stem .48, :secured to the part JIS.r This' passage has "aconstriction, as shown at 49 therein. 4A resilient element or coilY spring,r .'50, surrounding the stem 48, is'compresse'd between the lowerA end of tting 3l and` the upper edge of part 46 .to urge the valve member 45 towards seated position; This spring is weak butserves to seatthe valve inthe .event the Ipressure across the part 4B' isequalized.' It -will be seen that with 'the pilot valvef seated tot close the port 3Ib the-pressure within the' upper chamber of cylinder`32n Will'buildzup izo-be equaltojtliat eXteriorly-.of' 'the' housing. Thus, `the pressureV across thefseal 41,with"ltlie valve member 45 unseated, will be substantially v equal on' both sides and the spring 50 `Will close theA valve.- `However, the choke Apassage 49. vis smaller than thepas'sage controlled by valvei'30 solthat whenv the pilot valve opens, thepressure in the upper chamber of cylinder 321 will reduce to'substantially that within the tubing 'string' .8. Thus-when the pressure exteriorly of .the .valve housing, acting against one surface ofv the. head piece I9 of Athe-pilot valve motor, plus the force due to the pressure Within v.chamber 25- acting' against the annularfareaof stemf23ex`ceeds the force due to the resilient element :of the motol the-.pilot valve will f open" to bleed fthe pressure within thevv chamber surrounding` the-sternV 48 .and

`supplementing the pressure charge within the cap l5, which urges the part ina. direction tending tia-seat thevaive su. Howeven-opposingtms force is the force 'duetothe pressurefexteriorly of the valve housing, which enters Vportmlilija,

"passes-about the stem Sil-into theinteriornfthe bellows and'facts against an area equalirto the-.an-`

nular[surface represented by the difference .in

area of the interior'of the'sealedfupper end'ofthe v bellows Aas it joins the head piece :and the *area offstem'f'23 at the seal providedbyxoering 524.

Also, the force due to the pressure exterior of the housing-acting againstthecentral surface of valve member Suis. in an unse'atirig.'direction-butv the area of port .3|b, wherethe valve is to be used as a pilot valve, maybe/so small as -to be practicallynegligible vin its veiect on the. operation of the Valve. Then theiorce-of the pressure .x Within chamber .25.' Which-will be substantially that Within :the tubing .string .8,acting against a surface upon the valve 'membervequal to v.the

area of stem Z3 at 'the .O-ring `24 'less theyareaf 'j oi valve member Bexposed interiorly'of'portlb, urges the. stemfandxthe motor A.part l9y-invan1unseatingdirection. 5 my;

When "these total. unseating` .forces-marev-less 7 than the force of the resilient element, the member 30 will be closed, but when these forces exceed the force of the resilient means, the valve member 30 will be forced open. When this occurs, a direct passage from the exterior of the housing to the interior of the tubing string 6 is opened, which includes a choke passage e9 upstream from chamber and Valve member 3l?. Thus, while pressure iiuid will pass through the choke passage 49, ports 3Ib, chamber 25, ports 3Ia, and port 28 into the tubing string, nevertheless, due to the choke or constricted characteristic of passagedg, relative to the other portions of this passage, the pressure Within chamber 25 will be substantially that Within the tubing string 8. Thus, the motor will still be aiected in part by the pressure within the tubing string so that when this 'pressure falls below some predetermined value, as will be the case when the column of well fluid above the port 28 is lightened by the injection or gas into the liquid, the resilient means will cause the valve member 33 to reseat.v v

As heretofore indicated, it is preferred in many installations to keep the motor mechanism small and to provide a large port for accommodating large volumes of lifting gas. For this reason, it is preferred to use the Valve 3i) primarily as a pilotvalve to control opening and closing of a main or secondary valve 45. The valve member 45 is subjected to the force of gravity, the force of spring 5E), and the force of press-ure above and below the seal ring il and the arrangement is such that these pressuresmay be varied so as to produce a pressure diierential thereacross. it is this Variance of pressure that is relied upon to open and close the main valve l5 at selected intervals.

When the valve member 38 is closed, the pressure in the upper chamber within cylindrical sleeve 32 will'build up to equal the pressure eX- teriorly of the valve housing. If the valve member 45 is opened, the force of spring 59 will then cause the valve member 45 to seat. When this happens, the pressure within the lower chamber of cylindrical sleeve 32 will quickly become that of the tubing string 8 so Vthat only the reduced area of valve 45 Within the seat is exposed to the lcasing pressure. Thus, there is a differential area exposed to the pressure or" the gas to be charged into the tubing string, which tends to keep the valve member 45 closed. However, when the valve member 3i] opens, the pressure within the ,upper chamber of sleeve 32 quicklybleeds down to substantially that within the tubing string 8, because of the constricted character of passage 49 relative to the remainder of the passage communicating with the interior of the conduit 8. 'Ihen the force due to the pressure to be charged acting against the valve memberl5 urges `the valve member against the spring 5S, which is relatively weak, forcing it to its raised position lvalve member closes, the pressure across seal 41 will substantially equalize and spring 53 will cause positive seating of the valve 135. l

Takingup the operation of the system, it will be assumed for purposes of discussion that each of ithe three valves I3 shown in Fig...l hasa pressure charge which, when tested at-the ground, will cause the valves to open at 600 lbs. gauge pressure exteriorly of the devices. Where the preferred valve arrangement, utilizing the bellows having its interiol` sealed to the stem, is employed, the actual pressure within the pressure dome will be less than 600 lbs., and where the bellows have a cross-sectional area of substantially one inch and a wall thickness of 12j/1000 of an inch, the actual pressure charge within the dome will be about 525 lbs. gauge pressure. The temperature of the well fluids in most of the deep production of today is elevated and will in effect increase the pressure required to open the valves, but each of thevalves will open at substantially the same pressures. However, if pressure fluid is injected into the casing-tubing annulus, so as to raise the pressure within the annulus adjacent the wellhead to, say, 600 lbs., the weight of the column of fluid in the lower levels at which the valves are installed will increase the pressure at these levels to substantially evenly counteract the effect of an increased temperature.

It will be assumed that the liquid level within the casing-tubing annulus is above the Iirst or uppermost valve I3. The pressure uid or gas lift medium is introduced into the annulus through conduit I2, and where continuous ow is desired, the fluid will be metered through a choke or other suitable means at a constant rate. The total cross-sectional area of the passage for injecting gas into the tubing 8 of each of the valves I3 is gradually increased at successively lower levels because the Volume requirement of the lifting gas is greater at lower levels than at higher levels. However, the arrangement is such that when any two of the Valves I3 are open, the total areas of the passages for charging gas into the conduit 8 of the two valves will be greater than the area of the choke supplying the conduit I2 so as to produce adrop in the pressure within the casing-tubing annulus. This pressure drop will cause at least the uppermost of the two or more open valves to close.

The pressure within the casing 1 increases upon the closing of all but at least one of the valves and this forces the liquid leveldownwardly to uncover the highest one of the valves I3. Inasmuch as the control pressure at each of the valves is greater than 600 lbs., all of the valves will be open, and when the uppermost valve is exposed to the gas, the gas will ow into the tubing string 8 to stimulate production of well liquids within that conduit. At the same time, the liquid level will be lowered because more gas is being introduced into the casing than the single open valve I3 exposed to the gas can accommodate. When the second valve has been uncovered, gas will pass into the tubing through both the top two valves to aerate the column and produce the well fluids. However, this will bleed oi the casing pressure until the total forces tending to open the uppermost valve are not suicient to maintain the valve open. Thus, the uppermost valve will close due to both a drop in the casing pressure and a drop in the tubing pressure. The drop in the tubing pressure, of course, would be due to the lighteningy of the column of iluid above theV upper valve. The liquid level will then commence to drop toward the `third valve. When thisV valve is uncovered, the casing pressure will again drop until the second valve is closed and the dumping will continue until only the lowermost valve is open.

, When the hydrostatic head of well liquid has they feed from the earth formation into the well.l bore, the corresponding pressure drop interiorhof the chamber 25 and surrounding valve 30 willl cause the pilot valve to close.- However, immediately upon an increase of the tubingpressureV adjacentthe valve, the valve will open. It isvevident then that by proper regulation of the amount ofI gas charged into the casing, the

lowermost valve I3 will operate substantially con-v tinuously to stimulate production of the well fluids. t f v Thecontinuous ow of well fluids is desirable iny those vwells having a rapid rate of. production ofwell fluids from the'. well formation into the bottomof the hole. On the other hand, where thisrate of production is low, it is desirable' to permit time to accumulate a head of well liquids andto inject lifting gas intermittently. lIt has` been found'that these valves `may be caused-to operate intermittently whenever the column of Well 'liquid within theow conduit 8, above-a given Valvev I3 has been reduced in weight apredtermined amount. This reduction of the weight of the column of well liquids by aeration or injection of lifting gas, vmay be relied upon to effectithev intermittent opening of the lower or working valve. However, if desiredv for intermittent operations the valve or valves,V which may be relied upon as intermitters, may have their resilient means set to operatey at about 25 lbs. lessthan the dumping valves. By this expedient, the well may be produced intermittently with the elimination of any possibility of the opening of the upper valves and withfbut very small reduction in operating y pressure at the workingva'lves Qbviously, when` an fails duringthe working of the 'well so' as to open, it isthe n necessary to p ull ther stringfoftubing and repair -the upper valve. These pulling operations are veryexpensive and require a shutting in of the well during this time; However, with theV valve of this-invention, if the bellowsfails onan upper or dumpingv valve, the pressure within the bellows will not bleed off. but rather the casing pressure will bleedinto the bellows for itwill actually. be somewhat greaterthan the pressure charge within the cbellows. Thus, the vrvalvevmember; 301Will'be `held rmly against its seat even though thebellows should faiL'ranci this will pre ventzuntimely--opening of onev of the `upper or dumpinglv'alves. Y

1" InA goingI i'ntoa Well yfor the first time with gasA lift equipment, it is often impossible to determine in advain'eat just whatv ylevel the working, valve should-1 bef-installed'. 1 yIn` the 'installations'in 'accordance-Withthis invention, if it is determined thatthewellcanbe produced at one ofthe higher level' valves, this-may be accomplishedat a continuous flow bymetering the gas intoithe casing at la'rateequal'to .the capacity of the valve at the higher level for charging gas into Vthe conduit 8... From the foregoing it. will-be seen thatA this inventions 'one wen adapted to attain au 'ofthe I endsfand objects hereinabove-.set forthtogether upperfor dumping valve-v with other advantages .which are obvious and whichiare inherent to the structure. -Y

It/will be understood that certain features and subcombinations are of utility and may heemployed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. Y i y t.

As many possible embodimentsmay be made of lthe invention without departing from theV scope thereof, it is to be understood that all mat-' ter herein s'et'forth or shown in the accompanying drawingsis toV be interpreted as illustrative and notin'a li'mitingsense. This application isV a continuation-in-part'of Serial No. 80,792, filed March 11, 1949.

The-invention having been described, what'is claimed is:

4l. A gas lift valve comprising a housing having inlet andoutlet openings, a motor means within the housing, a resilient means urging a part of' member, and its actuatingconnection providingy an eifectivepressure face of substantial area'eX-. posedftov thevalve housing outlet with the valve member seatedwhereby it is subjectedto a pressure substantially that within the conduit into whichfthe valve will discharge when open, said.

face being so disposed that said last mentioned pressure will urge `said valve member toward open position and'of greater area than any so disposed effective faceof the valve member exposed to the valvel inlet with the valve member seated, said inlet being. constricted to a cross-section area smaller than the flow area past said valve member when the valve is open, said actuating connectionA arrangedto transmit the force of such pressure against such pressure face to the motor in a` direc.-

tion to oppose the resilient means. L

.2. In a gas lift -valve a housing, apressure re-j sponsive motor means ,therein with a part urged.

by avresilient element in one direction, said part havingl a-surface exposed to the pressure exterior ofthe housing and urged thereby in a direction.:

opposing the resilient means, said housing having a-chamber ltherein remote from the motor. means, anY outlet for the chamber and a relatively restrictedinlet, `a valve member and seat there-- for within the chamber for controlling iiowtherethrough, a rod `connecting the valve memberfto. the .motor part-and a sliding seal between :the Vhousing, and rodfto seal between the -,chamber; and motor means, `and an effective pressure-,facev provided by .the valve member and connecting;

rod-exposed, when the valve member is in closed position,-to.pressure within the chamberandtso disposedV that it will be urged .thereby in aHd-irec-ftion providing a force opposing the resilientfelement, said face being` of greater area gthajngl any so disposed effectiveface of. the valve member exposed to the chamber inlet with the valvem'emloeriseated..l i g f als' 3f. Apressureresponsive gas lift valveV comprising lfa housing, a fport;l with ,a seattherein, fa valve member-adapted ,toengage theseat to control! W therethrough; a :resilient means within they hous- .ing and :connected to the? valve member tof'urgey 1t toward seatedV` position;v said lresilient'- means havingapartfmovablymounted i' within 'the cas-J ing to provide a variable capacity sealed chamber therein with one surface exposed to the fluid exterior of the valve, said port being included in a passage sealed off from the resilient means and communicating with the exterior of the valve, a constriction in the passage relative to the port, intermediate the port and the exterior of the valve, the connection between the valve member and resilient means having a moving seal with the housing to seal on? the passage, the valve member having effective pressure area exposed, with the valve member seated, to a pressure substantially that downstream of the port and so disposed that said last mentioned pressure will urge said valve member toward open position, said area being greater than any so disposed effective area of the valve member exposed to the pressure exterior of the valve with the valve member seated.

4. A pressure responsive gas lift valve comprising a housing having a port with a seat therein, a valve member adapted to engage the seat to control flow therethrough, a resilient means within the housing and connected to the valve member to urge it toward seated position, said resilient means having a part movably mounted within the housing to provide a variable capacity sealed chamber therein with one surface exposed to the fluid exterior of the valve, said housing having a passage sealed oi from the resilient means and communicating with the exterior of the valve and including said port, the passage having a constriction therein relative to the port, said constriction being intermediate the port and the exterior of the valve, the connection between the valve member and resilient means having a moving seal with the housing to seal off the passage, the valve member having an effective pressure area exposed, with the valve member seated, to a pressure substantially that downstream of the port, said area being so disposed that said last mentioned pressure will urge said valve member toward open position, and being greater than any so disposed effective area of the valve member exposed to the pressure exterior of the valve with the valve member seated.

5. In a gas lift valve a housing having a chamber therein with major inlet and outlet openings and an intermediate valve seat, a major valve element controlling the seat and slidably mounted in the chamber with seal means about the major valve element within the chamber sealing oi part of the chamber from the major outlet opening, a resilient means urging the major valve element toward the seat, and means for selectively introducing to the chamber on the side of the seal remote from said major inlet and outlet openings, pressures substantially equal to the pressures exterior of the housing'and interiorly of a conduit with which the major outlet opening is to be connected respectively, said latter means including a pressure responsive pilot valve controlling a passage which includes the chamber and has an outlet port adapted to be connected to said conduit into which the valve is to be discharged, the passage communicating between the exterior of the housing and said outlet port, the pilot valfve comprising a valve member having an eiective pressure face exposed, with the valve member seated, to substantially the pressure within sucha conduit, said face being so disposed that said last mentioned pressure will urge said valve member than any-so disposed eiective face of 'the' valve from the said openings by a part carried by thev major valve element for selectively providing a pressure dierential across the major valve element to open and lclose same, said meansincluding a pressure 4responsive pilotvalve controlling a vent passage, which passage includes the latter part of the chamber and communicates between the exterior of the housing and a port connectible to a conduit into which the valve is to discharge, the pilot valve havingY a motor part having onesurjface exposed to pressure exteriorly of the housing and another surface exposed with the pilot valve in closed position, to pressure substantially equal to the pressure atrsaid port, the` said surfaces being so disposed thatboth of said pressures will act in a direction toopen the valve.

and saidY surface so exposed to the pressure of such port beingof greater area than any surface of the pilot valve which is exposed to the pressure exteriorlyof the housing with the pilot valve closed and to a different pressure with the pilot valve open, and a resilient means acting against the motor part inthe opposing direction.

'7. A gas lift valve comprising a housing, a motor means within the housing having a part urged by a resilient means in one direction, said part having a Asurface exposed to the pressure exterior of the housing to urge it in the other direction; a port in the housing, a valve member controlling said port, an actuating connection between the motor part and valve member, a substantial area of said valve member being subject, when the valve memberis in closed position, to a pressure substantiallyvthat within a conduit into which the valve will discharge when open, said area being so disposed that said pressure acting thereon Will tend to move the valve member to open position and being greater than any so disposed effective area of the valve member exposed to the pressure exterior of the housing with the valve member in' closed position, said actuating connection arranged to transmit the force of such pressure against such area to the motor part in a direction -to oppose the resilient means.

8. In a gas lift valve adaptable for use in conjunction with two well conduits for controlling injection of a lifting gas from one conduit into the other conduit to stimulate flow of well iiuids through the latter conduit, comprising a housing' with two separate chambers therein, `a pressure responsive means within one chamber of the housing, said means having va part urged in opposite direc-tions by a resilient element and: by'

the pressure exterior of the housing respectively, the other chamber constituting a part of a passage means adapted to establish communication between the conduits, said passage means being constricted betweenthe chamber and the exterior of the housing to the extent that substantially al1 of the pressure drop in fluid flowing through said passage means occurs across the constriction, a

valve member controlling flow through the latter chamber and having a power transmitting actuating connection with said part of the pressure responsive means,V said valvefmember having a surface exposed when the valve member. is in closed position to pressure substantially that within the conduit to be charged, said surface being so disposed that when said pressure acts therein it will tend to move said valve member to open position and being of greater area than any so disposed effective face of the valve member exposed to the pressure exterior of the housing with the valve member closed, and the force due to the pressure acting against said surface being transmitted by the valve member and its actuating connection to said part of the pressure responsive means to urge it in a direction opposite the direction in which it is urged by the resilient element.

9. A gas lift valve including a tting with a passage therethrough adapted to provide for flow of fluid under pressure from the exterior of the valve into a iluid container to which the fitting may be attached, a port with a seat therein making up part of the passage, a constriction in the passage relative to the cross sectional area of the port, such that substantially all of the pressure reduction in uid passing through the passage takes place across the constriction of the valve in operation, said constriction positioned intermediate the port and the inlet end of the passage, a valve member adapted to engage the seat to control flow through the port and having an effective area subject to pressure downstream of the port when in closed position and so disposed as to be urged by said pressure toward open position, said area being greater than any so disposed area of the valve member exposed tothe valve inlet with the valve member seated, and a pressure responsive motor connected to the valve member for actuating same, said connection including a rod extending from the fitting with a moving sealed connection therethrough, said motor having a part exposed to the pressure of fluid exterior of the valve and sensitive to varia- .tions therein and in the pressure downstream of said port to open and close the valve member.

10. In a valve adaptable for use in conjunction with gas lift operations in producing well liquids through a conduit by selective injection of gas under pressure into the liquid Within the conduit, a means for controlling flow of gas into the conduit in response to pressure within said conduit and the pressure of the gas to be injected therein including, a motor means having a part urged by a resilient element in one direction, a housing having a port communicating with the conduit to be charged, a valve member controlling the port, a connection between the valve member and motor part, the connection and motor part providing an area exposed to the pressure of the gas to be injected to provide a force opposing the resilient element, the valve member and its connection with the mot-or part providing a substantial area exposed at all times to a pressure substantially that Within the conduit to be charged, said last mentioned area being so disposed that said last mentioned pressure will urge -said valve member toward open position and, with the valve member seated, being of greater area than any so disposed effective face of the valve member exposed to the pressure of the gas to be injected.

11. In a gas lift Valve a housing having a chamber rtherein with major inlet and outlet openings and an intermediate valve seat, a major valve element controlling the seat and slidably mounted in the chamber, seal means about the major valve element within the chamber sealing 01T part of the chamber from said major outlet opening, a resilient means urging the major valve element toward the seat, and means for selectively introducing to the chamber on the side of the seal remote from said major inlet and outlet openings. pressures substantially equal to the pressures exterior of the housing and interiorly of a conduit with Which the outlet is to be connected respectively, said latter means including a pressure responsive pilot valve controlling a passage which includes the chamber and has an outlet adapted to be connected to said conduit into which the valve is t-o be discharged, the passage communieating between the exterior of the housing and said passage outlet, a constriction in the passage upstream from the chamber and a valve member included in the pilot valve with an effective face exposed, with the valve member in closed position, to substantially the pressure within said passage outlet, said face being so disposed that said last mentioned pressure will urge said valve member toward open position and being of greater area than any so disposed eiective face of the valve member exposed to the valve inlet with the valve member seated.

HENRY U. GARRETT. CLIFFORD M. PETERS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,342,301 Peters Feb. 22, 1944 2,385,316 Walton Sept. 18, 1945 2,391,605 Walton Dec. 25, 1945 2,465,060 Carlisle Mar. 22, 1949

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