w. c. TRAUTMAN Erm. FLow EQUALIZER ' Filed April 2s, 1945 55 2,413,896 ‘ 2 Sheets-Sheet 1 \ „y ' A. A. MEDDOGK Ar ron/vx ` .ii 2,413,896 “i”, i947 STATES PATENT OFFICE n 2,413,896 FLOW EQUALIzEn Walter C. Trautman, Los Angeles, and Alvin A. _ Meddock, North Hollywood, Calif., assignors to Bendix Aviation Corporation, South Bend, Ind., a oorporationot Delaware Application April 23, 1945, Serial No. 589,772 7 Claims. (Cl. IS7-»165) 1 2 A _ This invention relates to equalizer valves for Fig. l is an exterior view of a valve in accord equalizing ñuid ñowin a pair of branch lines, and ance with the invention. more particularly to a reversible equalizer valve of the ltype disclosed in application of Walter C. Trautman, Serial No. 502,877, illed September 18, Fig. 1. 1943, which equalizes the flow in a pair of branch lines irrespective of whether the ñow is from the of Fig. 2. common line into the branch lines, or from the branch lines into the common line. An object of the invention is to provide a re of Fig. 1: and - Fig. 3 is a section taken in the plane III-III ß A Fig. 4 is a section taken in the plane IV-IV ' Fig. 5 is a vsection taken in the plane V-V of Fig. 2, which is at right angles to the section of Fig. 4.A The valvedisclosed comprises a housing or cas ing consisting ot a body ID and a pair of end plates Il and I2, respectively, which are secured to op posite ends of the body by 4cap screws I3. The body defines a main cylinder I4, the opposite ends versible ñow equalizer valve that is particularly simple in construction and easily assembled and disassembled. ' Fig. 2 is a section taken in theplane lI-II of , Another object is to provide a reversible flow equalizer valve oi such construction that it` can be readily and inexpensively manufactured.' Other more speciñc objects and features of the of which are closed by the end plates II and I2 invention will become apparent from the de and which contains a main piston I5 which has tailed description to follow of a preferred embodi four check valves therein, to be described later. ment of the invention. The `main cylinder I4 contains two annular 20 The present invention is'an improvement of the grooves> I8 and I'I which are in constant commu valve disclosed in the aforementioned application nication with a pair o! outlet ports I8 and i9 " adapted to be connected to branch lines 20 and 2| Serial No. 502,877, which contains a shuttle valve consisting oi a short, pressure-responsive piston respectively. The piston I5 has a pair of an oi substantial diameter working in a relatively 25 nular grooves 22 and 23 cooperating with the cyl short cylinder and having a pair of piston valves Inder groove I6 to variably control now therein oi substantially smaller diameter extending from and also a pair of annular grooves 24 and 2li co its opposite sides into valve cylinders of corre operating with the cylinder groove I1 to control l sponding diameter. A reversible ñow equalizer flow therein. ~ valve also incorporates check valves for directing 30 The piston I5 contains four check valves for ñow to one set of ports controlled by the piston selectively communicating the different piston grooves 22, 23, 24, and 25 with opposite ends oi ‘ valves when .the flow is from the common line to the branch lines and for directing the fluid to the main cylinder. other ports controlled by the piston valves when the dow is from the branch lines into the common end 26 of the piston through a cylindrical pas line, and in the earlier application these check valves were positioned in the body of the valve sage 30. exterior of the piston.- , - - l . Thus. the groove 23 communicates with thelei't This passage 30 has a seat at its inner ’ " end which is normally closed by a check valve 2l, which is slidable inthe passage 30 and is urged into closed position by a helical compression spring 28 compressed between the left end ci' the valve 21 and a split retaining ring y2! in a groove provided therefor in the passage 30. Fluid can, therefore, flow from the piston groove 23 to the left end face 26 of the piston, but re 45 verse ñow is prevented. in accordance with‘the present invention, the structure oi the earlier application has been slm plii'ied, while preserving the same general mode of operation, by employing a single piston of sub stantial diameter and length as the piston valve, and utilizing the opposite ends of this piston as the pressure faces against which the controlling pressures are applied. Further simplification is effected by locating the check valves within the piston itself. This not only makes possible the ~ A passage 3| aligned with passage 30 extends ' into the piston from the right end face 32 .there of, but this is a blind passage provided primarily use of a much simpler and less expensive valve to lighten the piston, although it also saves an ad body, but facilitates the assembly of the check 50 ditional purpose to be described later. valves and reduces the weight oi the piston. A The piston groove 22 (Fig. 5) is also connected light piston is desirable because it has less iner to the left end 26 of the piston through cylin tia and responds more quickly to correct any drical passages 33 and 3| in the piston. The ' tendency toward inequality in the rates of flow. passage 33 extends into the piston from the right ln the drawings: 55 end 32 thereof, but it is closed at its right end 2,413,898 by a plug 35 having a groove containing a seal ing ring 31, the plug 35 being retained in posi~ tion by a split retaining ring 38. A check valve common line 55, and the rear end of the piston is exposed to the pressure existing in the passage 1 I, which is transmitted through a small passage 3S urged to the left by a helical compression 16 to the rear end of the piston. The result is spring flo compressed between the rear end of that when the pressure in the common line 55 the valve 39 and the plug 36 prevents ilow of exceeds the pressure in passage 1I by an amount fluid from the groove 22 to the left end of the suñicient to overcome the force of spring 65, the piston while permitting ñow in the reverse di piston 53 is moved to y:the right" to uncover the rection. ports 14 and 15 and permit ilow therethrough to The groove 2A in the piston is connected to the passages 10 and 1I. Since the differential the'rlght end of the piston through a cylindrical pressure must overcome the force of the spring passage ill containing a check valve 42 similar to 64 before the piston 63 is moved to uncover the the check valve 21, so that ñuid can flow from ports 14 and 15, the spring-actuated piston func the groove 24 to the right end 32 of the piston tions to produce pressure drops between the but cannot flow in the reverse direction. A hole 15 common line and the passages 10 and 1I when 44 entering the piston from the left end is pro the flow is from the common line 55 into the vided in alignment with the passage 4I to lighten valve. the piston, and provide a connection to be de When the ñow is from the valve into the com scribed later. mon line 55, the pressure in the passage 1I ex The groove 25 is communicated with the right 20 ceeds the pressure in the common line and this end 32 of the piston through a'passage 45 and . differential pressure acting against the right end a passage 135 similar to the pasages 33 and 34 of the sleeve 58 overcomes the force of the spring 59 and moves the sleeve to the left until the ports 14 and 15 are uncovered. respectively. A closure plug 41 having a sealing ring 68 prevents fluid flow between the passage 55 and the left end of the piston, and a check 25 The spring-controlled piston and sleeve, there valve 49 urged to the right by a spring 50, pre fore, function to introduce a desired pressure vents fiuid ñow from groove 25 to the right end drop at the ports 14 and 15, irrespective of the of the piston, while permitting reverse flow. direction of flow. The main piston I5 controls flow between the The valve functions as follows when the direc branch lines 20 and 2I and the opposite ends of 30 tion of flow is from the common line 55 into the the main cylinder I4, and the opposite ends of branch lines 20 and 2 I: the cylinder are connected to a. common line 55. Fluid entering the passage 56 from the com Thus, referring to Fig. 2, the common line 55 mon line 55 moves the piston 53 to uncover the communicates with one end of a> cylindrical ports 14 and 15 and permit fluid ñow through the passage 55 which extends through the body 35 passages 10 and 1I to the end chambers 12 and transversely with respect to the main cylinder 13 of the valve. If the flow through both pas it. The mid-portion of the passage is slightly sages 10 and 1I is equal, then the pressure drops reduced to form a cylinder 51 which slidably through the ports 14 and 15 are equal, and equal receives a sleeve 58 which is urged to the right pressures exist in the chambers 12 and 13, the by a helical compression spring 59 compressed 40 pressures being slightly less than that in the between the left end of the sleeve and a retainer common line 55 because of the pressure drops at ring 65, the latter being held by a split ring 6I. the ports 14 and 15, ' - The sleeve 58 has a shoulder 62 at its left end, Pressure fluid in chamber 12 functions to seat which shoulder seats against the shoulder at the the check valve 21 so that no ñow occurs there left end of the cylinder 51 to limit movement 45 past. However, the pressure opens check valve of the sleeve by the spring 59.. 39, permitting fluid to flow into the piston groove There is positioned within the sleeve 58 a 22 and past the shoulder 22a of this groove into piston 53 which is urged into the right end of the body groove I6 and thence into the branch the sleeve by a helical compression spring 64 line 20. At the same time, the pressure fluid in compressed between the piston and a closure 50 the chamber 13 holds the check valve 42 on its plug 65 which is screwed into the right end of seat, but opens the check valve 49 permitting the passage 55 and has a sealing ring 65 for ' fluid to now into the piston groove 25 and past effecting a fluid seal. The piston 53 has a Shoul the shoulder 25a thereon into the cylinder groove der 61 on its right end which abutts against I1 and thence to the branch line 2i. the shoulder at the right end of the cylinder 55 S0 long as the pressures are equal in chambers 51 to limit movement of the piston by the 12 and 13, the piston I5 will be centrally located spring S5. and the resistance to ñow from piston groove 22 Referring now to Figs. 3 and 5, the cylinder 51 past shoulder 22a into cylinder groove I6 will be is intersected by a pair of aligned passages 10 ~ equal to the resistance to flow from piston groove and 1I which extend to thel opposite ends of the 60 25 past shoulder 25a into the cylinder groove I1. body I ti (Fig. 5) and communicate with cham »Howeven if the fluid tends to ñow faster into bers ‘i2 and 13 deñned by the body member I5 branch 2i than into branch 20, the pressure drop and the end closure members II and I2, respec through port 15 (Fig. 3) will be greater than the tively'.V Suitable seais III and I2I are provided pressure drop through port 145, and the pressure to effect a fluid-tight closure between the cover 65 in chamber 13 will become less than that in plates il and I2 and the body. As is apparent, chamber 12, moving the piston I5 t0 the right the chamber 12 communicates with the left end and causing shoulder 25a to increasingly throttle of the piston I5 and the chamber ‘E3 communi flow into the branch line 2I and causing shoulder cates with the right end. 22a to decreasingly throttle flow into the branch Referring again to Fig. 3, the sleeve S8 has a 70 line 2û. The result is that the iiows are again pair of ports 1li and 15 in its wall, which ports substantially equalized by the movement of the are in constant communication with the passages piston, since the movement will be of whatever 1G end ’îI respectively, but are normally blocked extent is necessary to bring the pressures in the by the piston 63, The front end of the piston chambers 12 and 13 back to equality. 53 is exposed to the pressure of fluid in the 75 Of course, if the increased fiow occurs in the 2,413,390 6 _ ‘ . . branch 2li rather than 2l, the pressures are re versed and the piston moves in the opposite di is connected to the left end of the piston through rection to increasingly throttle flow from piston connected to the right end of the piston through groove 22 into the cylinder groove I6 and de creasingly throttle flow from the piston groove 25 into the cylinder groove I1. a port 8| (Fig. 4) and the hole 3|. Obviously, ‘ therefore, groove 18 always contains fluid at the same pressure existing at the left end of the pis ton, and the groove 19 always contains fluid at a port 80 and the hole 44, and the groove '19 is When the direction of flow isfrom the branch , lines into the common line, fluid entering the branch passages I8 into the cylinder groove I1 cannot iloW through piston groove 22 to the left end of the piston because check valve 3B is then seated. Hence, fluid flow from cylinder groove I6 can voccur only through the piston groove 23 and past the check valve 21 to chamber 12. Like wise, .fluid flowing from the branch line 2| ,into cylinder groove I1 cannot flow through piston groove 25 to the right end of the piston because l check valve 4Q is seated, and, hence, ñow can only occur from groove l1 through the piston groove 2li and past check valve 42 to chamber 13. Fluid howirfg through the chambers 12 and 'I3 passes through the passages 10 and 1| and out through the ports 14 and 15 to the common line 55, the ports 14 and ‘l5 being maintained open by pres sure transmitted from passage ‘II through pas sage 16 to the right end of the sleeve 58. The ports ‘lil and 15 introduce a pressure drop propor tional to the flow, and as long as the flows from the two branch lines 20 and 2| are the same, equal pressures exist in the chambers 12 and 13 and the throttling eiîect of shoulder 24a from cylinder groove Il to piston groove 24 is equal to the pressure existing at the right end of the pis- , ton. Except while the piston is movingto com 10 pensate for changes in resistance to flow in the twoy branch lines 20 and 2|, the pressures at the opposite ends of the piston are substantially equal. Whenever there is a substantial differ ence in the resistance to flows in the two branch 15 lines 20 and 2|, the pressures in the grooves I6 and I1 will be substantially different, and with out the grooves "I8 and 19, there would be a cross ilow of leakage fluid through the clearance be tween the piston and cylinder between the 20 grooves 23 and 24. However, the grooves 18. and 'I9 prevent such cross flow because the pressures in grooves 18 and 19 are always substantially the f same.' - » - -» As an example, assume that as a' result of sub 25 stantial increase in the resistance to flow through the branch line 20 as compared to the branch line 2|, ther piston I5 moves in such direction as to permit relatively :tree now from the piston groove 22 into the groove IB while greatly throttling 30 flow rfrom the piston groove 25 into the groove I1. ‘Under these» conditions, the pressure in cylinder groove I6 will be high compared to the the throttling effect of shoulder 23a to fluid flow ' pressure in cylinder groove I1, and withoutthe from cylinder groove I6 to the piston groove 23. grooves 18 and 19, there would be leakage of- fluid However, if fluid tends to flow into the valve fas-_ 35 from cylinder groove I6 into piston groove 423, ter from branch 2| than branch 20, the pressure thence along the clearance between the piston will become higher in chamber 13 than in cham and cylinder into the piston groove 24 and thence ber l2, moving the piston to the left to increas into the cylinder groove I1 and the line 2|. 'Ob ingly throttle iiuid flow at shoulder 24a and de viously, therefore, the ñuid entering the line 2| creasingly throttle fluid flow at shoulder 23a un-- 40 'would consist in part of ñuid ñowíng through til equality of flow is again restored. If the 110W the metering port 14 instead o1' consisting solely into the valve from branch line 20 becomes 1 of fluid iìowingv through the metering port 15, greater than the :dow from branch 2|, the re~ Vas it should be. However, such cross flow as verse condition prevails, the pressure in cham has been described is rendered impossible- by the "ber 12 rising above that inV chamber 13, and mov 45 groove 18 and 19 because those grooves are al `ing the piston to the right to increasingly throt Ways ñlled with ñuid that is at higher pressure tie How past shoulder 23a and decreasingly throt tling iiow past shoulder 24a. y ' ` It will be apparent Á‘that the placing of the _ check valves in the main piston provides a sim Aple ,structure that can be readily «manufactured» y and serviced. Furthermore, it provides a very simple body structure, requiring lmuch less ma than the pressure in either the cylinder groove ' I 6 or the cylinder groove I1 so that whatever leakage there is, is from the groove 18 »to the groove I6 and from the groove 19§to` the groove I1. As a result, regardless of the"'unavoidable leakage along the piston. all of the ñuid entering the branch line 2U ñows through the metering l , chine work than the valves of this type previous port 14 and all of the fluid that enters the branch ly ufactured. _ 55 line 2| ilows through the metering port 15. Ob lit is important in a valve of this type, partic viously, the grooves 18 and 18 could -be located in ularly when the flow is from the common line 55 the cylinder wall instead of the piston, but it is into the branch lines 2li and 2|, that all of the easier to place them in the piston. y huid entering one branch line 2li pass through If it is not necessary to control fluid now in the metering port it and that allof the fluid 60 both directions, the valve can be simplified by entering the other branch line 2l pass through eliminating all the check valves in the piston and the other metering port fi5„_._,_This means that one set of grooves on the piston. Thus, if it is there should be no lealragealongthe surface of necessary only to handle :dow from the common piston it from one body groove .i6 to the other line 55 to the branch lines 20 and 2|, the piston body groove il, or vice versa'. However, in p. 65 grooves 23 and 24 can be omitted. On the other hand, if now is only from the branch lines 20 tightly in' the cylinder that there is no leakage and 2| to the common line 55, the piston grooves whatsoever. We, therefore, maire provision that 22 and 25 can be omitted. - Hence, the same body whatever leakage there is along the piston into can be'used for both reversible and non-reversible _ grooves it ‘and l1 'will be from that end of` the ‘models of the valve. thereby reducing production piston adjacent the groove. This is done by pro cost, and enabling conversion of valves in the > practical valve, the piston cannot be ilttediso viding a pair of annular grooves i8> and 19 near the middle of the piston and connecting each groove to the end oi _the piston to which it is held by merely changing the pistons. We claim: ` . i 1. A new proportioning valve comprising a closest. rlFhus, referring to Fig. 5, the groove ‘I8 75 body having a common fluid connection and a 2,413,896 8 pair of branch connections and deñning a cylin ~der having a pair of longitudinally-spaced ports in its cylindrical wall respectively connected to said branch connections, said body also having fluid passages respectively connecting said com mon connection with the ends of said cylinder; means for producing pressure drops in said pas sages proportional to ñuid flow therein; a piston in said cylinder movable in response to the djf~ ference in pressure acting on opposite ends of said cylinder in either direction from a neutral posi tion of flow is from said main connection to the branch connection. 4. A valve as described in claim l in which said fluid passages in said body connecting said com mon connection with both ends of said cylinder comprise: a first passage extendingr through said body and connecting at its opposite ends to oppo site ends of sai‘d cylinder, a second passage ex tion, said piston having a pair of annular grooves tending through said body at an angle to and intersecting said first passage, one end of said second passage constituting said common iiuid connection, means closing the other end of said cooperating respectively with said cylinder ports second passage, a sleeve reciprocal in said second and having passages therein communicating one passage having a pair of diametrically opposite ports communicating with opposite ends of said groove with one end face and communicating the other groove with the other end face of the piston; each of said piston grooves and its as first passage, a piston reciprocal in said sleeve to cover and uncover the ports therein, spring means urging said sleeve in one direction and sociated cylinder port being so positioned relative separate spring means urging said piston in the to each other as to equally throttle fluid flow at said two ports when said piston is in said 20 opposite direction to normally cover the ports in said sleeve, one end of said sleeve and one end neutral position and to unequally throttle duid of said piston being exposed to fluid pressure ñow at said ports when the piston is displaced in said one end of said second passage, and means either way from said neutral position, the ar for applying fluid pressure from one end oi’ said rangement being such that movement of said pis- ' ton in response to departure of the pressures at 25 ñrst passage to said other end of said second pas sage, the construction and arrangement of said opposite ends of the piston from equality variably sleeve, piston, and springs being such that said throttles flow through said ports in such direction piston is displaced to uncover said sleeve ports as to nullify said departure and maintain the in response to pressure in said one end of said 2_A valve as described in claim 1 in which 30 second passage exceeding the pressure in the other end and said sleeve is moved to uncover said said body comprises a main member having two sleeve ports in response to pressure in the other parallel passages extending longitudinally there end of said passage exceeding the pressure in through and a, pair of detachable end closure pressures equal at the opposite ends of the piston. said first end thereof. . members in sealing relation with said main mem 5. A valve for proportioning the ñow rates in ber "for interconnecting adjacent ends of said 35 a pair of ducts connected in parallel relation to parallel passages, one oi.' said parallel passages constituting said cylinder and the other of said parallel passages having connection intermediate each other and in series with a common duct containing means for circulating fluid in either direction therethrough said valve comprising: a its ends with said common connection through 40 body member deñning a, cylinder having a pair said means for producing pressure drops. of longitudinally-spaced ports in its cylindrical 3. A flow proportioning valve comprising a wall adapted to be connected to said pair of ducts, body having a main fluid connection and a pair and having a common connection adapted to be of branch connections connected by branch pas connected to said common duct; means in said sages to said main connection and having iiow body connecting said common connection with resistance means in each branch passage and opposite ends of said cylinder and producing pres throttling means in each branch passage re sure drops proportional to flow in response to sponsive to departure of the pressures ther‘ein fluid iiow between the said common connection between the flow resistance means and the and opposite ends of said cylinder; a piston in said throttling means from a given ratio for varying 50 cylinder reciprocal in either direction from a said throttling means so as to nullify said de neutral position, a iirst pair of annular grooves parture and maintain the iiows in the two branch on said piston associated with said respective passages in constant ratio, in which: the ' cylinder ports and connected by passages through throttling means comprises a cylinder having a said piston to opposite ends thereof for inversely pair of ports respectively connected to said branch 55 throttling fluid ilow from said respective cylinder connections; a piston movable in said cylinder ports to opposite ends of said cylinder in response in either direction from a neutral position and to movement of said piston, the arrangement of having four annular grooves thereon, two on op tbe grooves being such with respect to their asso posite sides of one cylinder port, and two on ciated cylinder ports that the flow in each port opposite sides of the other cylinder port when 60 ' is increasingly throttled in response to an in said piston is in neutral position, said piston hav crease in the pressure in the end of said cylinder ing separate passages therein connecting the two connected to that port relative to the pressure grooves of one pair to one end face of the piston in the other end when the direction of flow is and connecting the two grooves of the other pai! from said ports to said common connection; check to the other end face of the piston; check valve 65 valves in said piston passages preventing flow means in said piston passages restricting ñow in therethrough from the ends of said piston to said the two passages communicating with each end first pair of piston grooves; a second pair of of the piston to opposite directions; the arrange annular grooves on said piston associated _with ment being such that the flow in either cylinder said respective cylinder ports and passages in said port is increasingly throttled in response to an 70 piston connecting said grooves to opposite ends increase in the pressure in the end of said cylinder of the piston, for inversely throttling fluid flow connected to that port relative to the pressure in from opposite ends of said cylinder to said respec the other end of the cylinder when the direction tive cylinder ports in response to movement of the of flow is from the branch connections to said piston, the arrangement of said second pair of main connection and vice versa when the direc 75 grooves being such with respect to their asso~ - annesse t@ eyiinder :norte that the iiiovv in each port piston when the piston moves in response to diii’erences in the pressure drops through said resistance means, said cylinder and piston hav de easine'iy throttled in response to en in crenae in the pressure in the end o1’ said cylinder cenneeted to that port relative to the pressure in, the other end when the direction of ?iovv is from said common connection to said ports, and cheer: valves in said last-mentioned piston pas ing cooperating sliding surfaces separating said ports and providing a leakage path between said ports, a pair of annular grooves in one of said surfaces interrupting said leakage path, and pas ior ereventine9 tiow therethrough from said sage means connecting each groove to the aci» second ïoair ot grooves in the piston to the ends ’ " i grieten., nive tor the distribution of üuids com' nrieing: means for dividing a fluid ñovr along two patire, means in each oi said paths adapted to oder a resistance to ñuid ñow, a cylinder having its ends communicating with said paths, a. piston in the cylinder, and ports in the cylinder provid ing a continuation of said paths, said ports being throttled by said piston and being adapted tohave their tree creas inversely varied by the i’ . M jacent end of said cylinder. 7. A valve as described in claim i having a second pair of annular grooves interrupting the ` leakage path through the piston cylinder clear ance between said cylinder ports, and means pro viding fiuid connection between each groove of said second pair and the end or said cylinder ad jacent that groove. ' WALTER‘C. TRAUTMAN. ALVIN A. MEDDOCK.