US2625177A

US2625177A - Pilot operated quick opening control valve

Info

Publication number: US2625177A
Authority: US
Inventors: Joseph F Ziskal
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1947-11-19
Filing date: 1947-11-19
Publication date: 1953-01-13
Anticipated expiration: 1970-01-13

Description

Jan. 13, 1953 J. F. zlsKAl.

PILOT OPERAIEO QUICK OPENING CONTROL VALVE Filed Nov. I9, 1947 f/wezifof nfosejokp Patented `lan. 13, 1,953

PILOT OPERATED QUICK OPENING CONTROL VALVE Y Joseph F. Ziskal, Cicero, Ill., assignor to lInterv national Harvester Company, a -corporation of New Jersey Applicatie November 19, 1947 Serial. Nef 786@8 2 Claims.. 1

'This invention has to do with a control for connecting the output of a constant delivery pump with a place for delivery of liquid at rel-a'- tively low pressure uponV termination of the connection of the output with a place for delivery of 'liquid at a, relatively high pressure, the control employing a by-pass passage and a bypass valve therein which is opened for providingcommunication between the pump output and the place for delivery at low pressure.

This invention constitutes an improvement over by-pass valve control mechanism disclosed in the copending application of` Clarence A. Hubert and Joseph F. Ziskal, Serial No. 689,732, filed August 10, 1946, for Hydraulic Ram and Control Therefor, nowV abandoned, and continuation led June 18, 1 952, Serial No. 294,394. Such improvement concerns an improved plunger of a fluid actuated control actuator of the apparatus for opening Vthe by-pass valve, and it is the general object of this invention to provide an improved plunger structure wherein there is a spring which is energized by an initial advancement of a part of such structure for developing a force which is subsequently for effecting wider opening Qf the ey-Dess Yell/e @han would @Geur Witheet. the Pieenee ei ihe'epfiig- A by-pass valve operating plunger employing independently axially' iiieiiabie parte ef," which one is operable when axiallyadvanced to unseat a seated member 'o'fftlembygpass valve for open? in'gsuch valve, and theotler of such parts being advan'ceable under fluid pressure lfor compresf sing ua spring duringan initial'advancement of such other 'part' andthereby energizing the spring for enabling it to project the valve meinber farther from' its seat subsequent to an initial unseatingl thereof While the spring reacts against said otherl part; and ,the lprovision of a new Huid actuated plunger heffing aie-.ily eX- pandable and :ontractable'parts together with a partially compressed spring tlienebetween urging said parts `into"an expanded condition and means for limiting the degree of expansion of said parts under the force of said spring.

These and other desirable objects inherent in and encompassed by the-invention will become apparent from the ensuing specification and the drawings, wherein:

Fig. 1 is a partially diagrammatic view of a hydraulic system employinga constant delivery pump and by-pass valve and illustrating a bypass valve operating plunger constituting a pre'- ferred embodiment efiiie ieveiitiee. fer iiiieeeiiiie 'a' seatable member of such valve.

Fig. 2 is a fragmentary sectional View taken on a plane which extends axially through a multiple-spool valve of Fig. 1, and illustrating such valve in an operating position in contrast to the neutral positionv shown in Fig. l.

With continued reference to the drawings, the invention is there illustrated in conjunction with a hydraulic circuit whichY is adapted to selectively deliver fluid under high pressure conditions from the output side of a constant delivery pump I Ito either end ofv a two-way operable hydraulic ram I2 or to diverttlie fluid from the pump at relatively low pressure tol a reservoir (not shown) upon the rain piston I3 reaching a predetermined position in the ram cylinder under force of theVV high pressure iiuid. The significant structural differences in the hydraulic system herein disclosed and the disclosure in said copending application, Serial No. 689,732, is con'n'ed'to a plunger structure It which is advanceable'in a cylinder |5 to the position illustrated in l for unseating a bypass valve ball member 'I6 from a seat I'I of a byvpass valve I8. The corresponding plunger structure disclosed in the copending application 1S e Solid er rigid eieiiieiiiiii eeritreei' ie the febiieeied eiiiieifiii'e '.4 Whielieiiieleye e periieilv compressed spring I9 held captive between tele'- scopically assc ated parts 2| and 22. The part 2| is a cup-shped member having a central bea-ries eren' 2132111 .its .betteln er left end# A cylindrical.' side wall of the part 2| slides as a piston in the cylinder I5. yThe part 22 comprises a stem 24 "having a pilot ange 25 projecting radially from acentra'l-` portion thereof for slidingva'xially upon the'cylindrical inner periphery 'of the part 2 I'.

The left end of the stern 2.4 projects through and is piloted in thev bearing opening 23, and a retaining pin ZS'entending diametrically through the leftend portion of the stem 24 is abuttable against the left end of the part 2| for holding the partially compressed' Vspring I9 captive between the ange 25 and the bottom of the cuplike part 2|. 'A' breather opening 2'I in the flange 25 facilitates expansion and contraction of the parts 2| and A22A. enplanation of the mode of operation of this plunger'structure appears hereinafter in conjunction withA the opn eration of the entire system of which it forms an element operating in sequence with other elements.

A spool valve structure 3| comprises a multipleported cylinder 3,2 in which a multiplefepool Valve element 33 is axially slidable An annular inlet chamber 34'within the cylinder s2 between lands and 36 of the element 33 is connected with the output side of the pump II through diagrammatically illustrated conduits 29 and 3D and a cylinder port 38. When the spool valve element 33 is in the neutral position illustrated in Fig, l, the fluid in the chamber 34 can escape through neither the admission valves 35-39 nor `iii-41. Consequently, uid of the constant delivery pump II is discharged through the conduit Also communicating' with the control chamber 46, through a portion of the passage 43, is a control passage 4l which has branches 4la and 4l!) leading respectively to ports 4S and 49 of control valves 43-5I--52 and 49-53-54. With the spool valve element k33 in the neutral position or" Fig, l, each of the control valves 43--5I-52 and 4-53-54 is closed, wherefore the fluid entering the transfer passage 43 from the by-pass passage 42 is effective for creating uid p-ressure in the control chamber 46 equal to the pressure in the 11p-stream portion of the by-pass passage 42, that is, that portion of the by-pass passage 42 which is on the up-stream side of the by-pass valve seat VI. Since the plunger structure I4 presents an area to the control chamber 46 in eX- cess of the area circumscribed by the by-pass valve seat I'I, a unit pressure of fluid in the chamber 46 equal to and in fact somewhat less than the unit pressure of fluid in the up-stream portion of the ley-pass passage I42 will be effective L for advancing the plunger structure I4 to the right to unseat the by-passvalve member I6 and maintain the same unseated against pressure of fluid in said up-stream passage portion in the manner illustrated in Fig. l.

Prior to the unseating of the valve member I6, the entire plunger structure I4 will be somewhat to the left of the position illustrated in Fig. l. The spool valve element 33 will then be either to the left or the right of the neutral position of Fig. l. Assuming the valve element 33 to have been moved to the left of neutral as illustrated in Fig. 2 by a manual force applied to the lower end of a lever by a pivotally connected control rod 56 while the upper end of the lever 55 is constrained against movement by a pivotal connection 5l with a piston rod 58 of the hydraulic ram I2, the control valve 4B-5I-52 will have been opened. This permits escape of fluid from the transfer passage 43 to the reservoir through a conduit 59. Such escape of iiuid through this control valve causes a diminution of the fluid pressure in the control chamber 45 because the escape of such fluid is at a substantial rate compared to the replacement capacity of the small bore 45 in the plug 44. With this diminished pressure of the fluid in the control chamber 46, the pressure of fluid in the up-stream portion of the by-pass passage 42 together with the force of a compression spring 6i, will prevail over the force of fluid pressure upon the left end of the plunger structure I4 and cause seating of the by-pass valve member I6.

With delivery or output of the constant delivery pump thus precluded from escaping past the by-pass valve I8, and only an inconsequential 4 quantity of the output capable of escaping through the small bore 45 in the uid transfer passage 43, essentially the entire output of the pump is delivered through the conduit 3B and the port 38 into the valve chamber 34. However, since the spool element 33 is then in a position wherein the delivery valve 35--33 is open, the fluid introduced into the chamber 34 is discharged through the port 39 and a conduit 62 into the left end of the hydraulic ram I2. Thus the ram piston I3 is moved to the right, causing discharge of iluid through a conduit 63 and the port 4I of the then opened control valve 36-4I, thence through an axial bore 54 in the valve spool, thence through'the port 52 and the conduit 59 to the reservoir.

Movement of the ram piston I3 to the right under the circumstances just explained, causes movement of the upper end of the lever 55 to the right while the lower end of said lever is held against movement by the set control rod 55. This pivoting of the control lever 55 causes retraction of the valve stem 33 toward neutral, and concurrently with the piston I3 having moved to the right a distance correlated with the amount of manual movement initially imparted to the lower end of the control lever 55 for displacing the spool element from the neutral, said valve spool element will be returned to neutral. The delivery valve 35-39 will then be closed as will the delivery valve 35-4I, hydraulically locking the piston I3 against further movement. The control valve 48-5I-52 will also be closed, precluding further escape of the fluid entering the transfer passage 43, wherefore pressure quickly builds up in the control chamber 45. As the pressure is thus caused to increase in .the control chamber 46, an increasing force is applied to the left end of the control plunger part 2|, causing this part to move to the right, the by-pass valve member I6 then being seated at I'I. Concurrently, the pressure of fluid in the up-stream portion of the by-pass passage 42 together with the force exerted by the spring 6I will be urging the valve member I6 seated and will prevail over the initial force transmitted from the fluid ofV increasing pressure in the chamber 46 against the plunger part 2| through the'compressible spring I9 and the part 22 in an up-stream direction against the valve member I6. During this ephemeral time that the pressure in the up-stream passage portion prevails over the pressure in the control chamber 46, in maintaining the valve member I6 seated, the part 22 will be constrained by the seated valve member against advancement to the right While the part 2 I, which is being advanced by the increasing pressure of iluid in the chamber 46, causes the spring I9 to be compressed and energized.

Eventually the force transmitted to the valve member I6 through the compressed spring I9 and the part 22 will reachV a magnitude exceeding that of the combined force of the uid in the up-stream passage portion and of the spring 6I and cause unseating of the member. The initial unseating of the valve member I6 will allow escape of fluid therepast over the seat II and outwardly of a down-stream portion of the passage 42 and a conduit 55 to the reservoir. Such escape of fluid through the cracked (initially opened) by-pass valve diminishes the pressure in the up-stream portion ofthe passage 42, enabling the compressed spring I9 to instantly expand to its captive limit 'determined by abutment of the stop pin 26 ywith the left end of the part 2l; While 'so'expandig the spring IQ reacts against the'part 2l, "whicli'is maintained in position by theinon-compressible liquid, and projects theV part 22 and the valve member IB sufficiently far to open the by-pass lvalve widely. Such wide opening ofthe by-pass valve I8 enables the iiuid from the constant delivery pump to escape throughA the by-pass passage at lower pressure than ifv such valve'were less widely opened. Diminished by-pass pressure involves less heating of the by-pass liquid and also requires less energy for driving thev constant de livery pump.

The fabricated plunger I4v employing the spring I9 is capable of causing wider opening. of the by-pass valve than a one piece or rigid plunger in identical systems where such plungers are installed. If a rigid plunger were substituted for the plunger` structure I4, the increase of pressureA of the liquid in the control chamber 46 would eventually reach a magnitude for bodily advancing the entire rigid` plunger for initially unseating the by-pass valve member I5 at the same chamber pressure required for causing the plunger structure I4 to initially unseat such valve member. However, because of the noncompressible character of the liquid in the control chamber and because of the rigid character of the previously employed plunger, this initial cracking of the by-pass valve and the diminution of pressure inthe up-stream portion of the bypass passage would not be followed by an accelerated projection of the by-pass valve member into a wider opened position. The rigid plunger and the valve member would be more gradually advanced to the right by the increased volunieor non-compressible liquid accumulating in the control chamber until a balanced status is reached wherein the combined fforce of the uid in the Lip-stream portion of Vthe by-pass passage and the spring 6I acting in a down-stream direction upon the by-pass valve member equals the force exerted in an up-stream direction upon said valve member by liquid in the control chamber 45. This balanced status is eventually reached because diminution of pressure in the up-stream portion f the by-pass passage directly controls the pressure in the control chamber 4S through the transfer passage 43. But when the fabricated plunger structure herein disclosed is employed, a greater quantity of fluid is introduced into the control chamber 46 prior to cracking" the by-pass valve because of the permissible advance of the plunger part 2| by the compressible spring I9. After cracking of the by-pass valve, the energy in the compressed spring' projects the valve member I6 off its seat a distance which is greater than otherwise in an amount proportional to the additional volume of iiuid in the control chamber 4S. 'I'his results in all of the displaceable parts, the structure I4 and the member I6 being displaced to the right a greater distance than if the spring I9 were not present, and the consequent lower pressure in the up-stream portion of the discharge passage 42 does not subsequently retract the valve member I and the plunger structure I4 to a position that would be occupied thereby if a plunger not employing the spring i9 were used. With the valve member I6 initially projected farther from the seat I'I by the spring I9 a corresponding initial lower pressure will prevail in the up-stream portion of passage 42, causing lower pressures to obtain in bothl thS passage portion and in the control chamber at which a balanced position is established for said valve member. Substitution ofa plunger structure like I4 for a rigid plunger in a cylinder I5 of apparatus like that illustrated in the present drawings has caused reduction of by-pass pressure from approximately- 45 lbs. per square inch to approximately l0 lbs. per square inch.

Movement ofv the valve spool element 33 from the neutral position of Fig. 1 in the opposite direction to that illustrated'in Fig. 2 will commence a sequence of operations similar to that described above but causing the iiuid from the valve chamber 34 to be discharged through the port 4I and the conduit 63 into the right end of the ram cylinder I2 and discharge of iiuid from the left end ofsaid cylinder through the conduit S2, port 39, valve spool passage 64, and thed port 54 to the reservoir. This opposite movement of the valvel spool element will also cause the control valve 49-53-54 to establish communication between the control chamber 46 and the reservoir with the eifect ofv the control valve 48`5I52 as explained above. The principal difference in the operation ofv the apparatus is to cause movement ofthe ram pistonl I3 in the opposite direction, and upon the spool valve element 33 being returned to` neutral when the movement of the ram piston is completed, the closing of theA control valve 49-53-54 will terminate escape of fluiddelivered into the transfer passage 43 and cause the building up of pressure in the control chamber 46 for again opening the byfpass valve I8.

A pressure relief valve 'I-I is normally inoperative. This relief valve comprises a plunger 12 urged to the right by a spring 73- which normally maintains a perforated stem 14 in the position illustrated in Fig. 1, but responsive to abnormal pressure in the by-pass passage 42, this plunger and the stem 'I4 will be forced to the left to carry holes 'I5 of the stem 'I4 into communication with a passage 'I6 which is communicative with the reservoir through the conduit 65.

Having thus described a single preferred form or" the invention with the view of clearly and concisely illustrating the same, I claim:

l. In apparatus for controlling the flow of liquid through a by-pass passage; a by-pass valve disposed in said passage between up-stream and down-stream portions thereof and including a valve seat circumscribing said passage, and a valve member seatable in a down-stream direction upon said seat for closing such seat; means for unseatng said valve member comprising a control cylinder, a plunger structure blocking off a control chamber in the cylinder and comprising vparts which are individually advanceable axially of the cylinder by the force of liquid under pressure in said chamber, and captive spring means between and distortable by said parts for exerting a valve-opening force through one of said parts against the valve member in an up-stream direction to displace the same from said seat pursuant to advancement of the other of such parts by the force of liquid under pressure in the chamber; a liquid transfer passage communicating between said chamber and upstream passage portion, said plunger structure having a transverse area subjected to the liquid in the chamber exceeding the area embraced by the Valve seat wherefore an advancing force exerted on the plunger structure by liquid in the chamber Will exceed a seating force exerted on the valve member by liquid in the up-stream passage portion without the unit pressure of liquid in the chamber necessarily exceeding that of the liquid in saidvpassage portion; a control passage communicative with said chamber and a place for liquid delivery at low pressure relatively to the pressure in the up-stream passage portion; and a control valve in said control passage, said control valve having ports and passages arranged when in open position to cause diversion of said liquid through the control passage at a rate diminishing the pressure of liquid in the chamber suiciently that the pressure in the up-stream passage portion prevails in holding the by-pass valve member seated and when in closed position to trap the transferred liquid in said chamber and increase the pressure therein suiciently to cause said advancement of the plunger structure parts.

2. In apparatus for controlling the flow of liquid through a by-pass passage; a by-pass valve disposed in said passage between up-stream and down-stream portions thereof and including a valve seat circumscribing said passage, and a valve member seatable in a down-stream direction upon said seat for closing such valve; means for unseating said valve member comprising a control cylinder, a plunger structure blocking oi a control chamber in the cylinder and comprisf ing axially expanded telescopic parts which are advanceable axially of the cyiinder by the force of liquid in said chamber, spring means disposed between said parts and partially compressed thereby, and means precluding further expansion of the telescopic parts by force of the compressed spring while accommodating further contraction of the parts to further compress the spring, the force of said further compressed spring being exerted through one lof said plunger parts against the valve member in an up-stream direction to displace the same from said seat pursuant to advancement of the other of such parts by the force of .liquid under pressure in the chamber; a liquid transfer passage communicating between said chamber and the up-stream passage portion, said plunger structure having a transverse area subjected to the liquid in the chamber exceeding the area embraced by the valve seat wherefore an advancing force exerted on the plunger structure by liquid in the chamber will exceed a seating force exerted on the valve member by liquid in the up-stream passage portion Without the unit pressure of liquid in the chamber necessarily exceeding that of the liquid in said passage portion; a control passage communicative with said chamber to deliver liquid at a low pressure relatively to the pressure in the up-stream passage portion; and a control valve in said control passage, said control valve having ports and passages arranged when in open position to cause diversion of said liquid through the control passage at a rate diminishing the pressure of liquid in the chamber suiciently that the pressure in the Lip-stream passage portion prevails in holding the by-pass valve member seated and when in closed position to trap the transferred liquid in said chamber and increase the pressure therein suiciently to cause said advancement of the plunger structure parts.

JOSEPH F. ZISKAL.

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

UNITED STATES PATENTS Number Name Date 546,441 Vogt Sept. 17, 1895 1,546,243 Kimmerling July 14, 1925 2,091,596 Kluppel Aug. 31, 1937 2,362,713 Mott Nov. 14, 1944 2,399,756 Mott May 7, 1946