US2417217A - Fluid flow control device - Google Patents

Description

v 1 2a4 2 254 :5 8 g m 282 INVENTOR,"

2/! y HENRY ScHREOK Mil-ch 11, 1947. H. S CHRECK 2,417,217 FLUID FLQW CONTROL DEVICE Filed May 8, 1943 III 27 z r 4 FIG. I. 4 v

ATTORNEY Patented Mar. 11, 1947 I 2,417,217 FLUID FLOW CONTROL DEVICE Henry Schreck, Beloit, Wis., assignor to Fairbanks, Morse & of Illinois 00., Chicago, Ill., a corporation Application May 8, 1943, Serial No. 486,193

1 Claim. (Cl. 277-29) This invention relates to fluid impulse operation of mechanism such as valves and the like, and refers in particular to an improved fluid flow control device for hydraulic actuating systems such as that disclosed in my copending application entitled "Hydraulic operation of mechanism, filed May 8, 1943, and bearing Serial No. 486,192, now being Patent No. 2,396,392, issued March 12, 1946. I

An object of the invention is to provide a control valve device for operative association with a fluid flow line of a fluid pressure actuating sys tem such as that shown in said Patent No. 2,396,392, wherein the control valve is adapted for opening the flow. line in response to fluid pressure such as to permit substantially unrestricted I fluid pressure delivery through the line, and for. throttling return flow of fluid through the valve.

An object of the invention is to provide a relatively compact and effective control valve device for the punpose indicated, which may be readily and closely adjusted for regulating the release or return flow of fluid pressure therethrough to any desired degree.

Further objects and advantages of the present improvements will appear readily from the following description of a preferred embodiment of tihe device as exemplified by the accompanying drawings.

While the impro"ed control device providing the subject of the present application, may be readily employed in fluid pressure systems generally, wherein control devices of this character are required or preferred to afford predetermined desired fluid flow characteristics, the device is particularly suited to hydraulic valve actuating systems for internal combustion engines and the like. Accordingly, it is preferred herein to describe andillustrate the device in operative association with an engine valve actuating system of hydraulic impulse type, of the form and arrangement disclosed in Patent No. 2,396,392 heretions of the pump inabove mentioned, the material parts of which are incorporated In the drawing: Fig. 1 is an assembly view, in elevation, of an engine shown in part only, incorporating a hydraulic valve actuating system including the fluid flow control device of the present invention, and Fig. 2 is an enlarged sectional elevation of the control valve, at the head end of the pump shown in Fig. 1.

Referring first to Fig. 1 of the-drawings, there are illustrated certain portions of an internal combustion engine, generally designated by the herein by this reference.

numeral Ill, including in the portion thereof shown, a cylinder assembly II extending above the engine crankcase (not shown), Mounted on the engine camshaft casing shown in its upper portion 22, and adjacent the cylinder II is an actuator pump 23 preferably of reciprocating plunger type, which is cam-actuated preferably from the engine camshaft 26 within the casing 22. The pump is supplied with operating fluid from a source provided by a tank or fluid pump indicated diagrammatically at 21, through a supply header 28. A feed pipe 30 connects the source 21 to one end of the header 28, while the opposite end of header 28 is connected to source 21 by a return pipe 32. When the source of operating fluid is provided by a tank, as at 21, it may be somewhat elevated relative to the header 28, as shown, in order to provide a desired initial fluid-pressure head in the header. There is thus provided a closed fluid system with fluid circulation therein maintained during engine operation, either by the pressure delivery function of the fluid source 21 when constituted by a fluid pump, or by the suction and fluid discharge func- 23, as will appear more fully hereinafter.

Associated with the cylinder head 35 of the cylinder II is a valve assembly embodying a valve (not shown) which is actuated by a hydraulic motor indicated generally at 40 incorporated in the valve assembly as a part thereof. Actuating fluid is delivered to the motor 40 by the pump 23, through a conduit 42 and the control valve device 43 forming the subject of the present invention and hereinafter to be described, the latter by preference being arranged at the discharge end 44 of the pump.

Turning now to the fluid pump and control valve unit 23-43 the pump thereof includes a supporting frame or casin I54 having a mounting flange I 55 near its lower end, for assembly securementupon the upper wall of the camshaft casing 22 (Fig. 1), as by mounting studs or bolts I58. The pump plunger (not shown) within casing I54 includes a cam-follower frame I12,

the latter operatively supporting a cam-follower roller I15 which engages a cam I16 of a predetermined preferably symmetrical contour not here illustrated, fixed upon the engine camshaft 26 referred to hereinbefore. A suitable compression spring not shown, is provided to urge the pump plunger and cam follower downwardly as for maintaining cam-following engagement of the roller I15 with the cam I16.

The fluid pressure delivery from the pump 23 engine operation is directed through the valve device 48 presently to be described, and through conduit 42 (Fig. 1) to the pressure chamber of the valve motor 4...

and upon pressure release of the fluid delivery to extent, whereby to prevent oscillatory surging of by the pump.

pump back into the supply has secured thereto as by set screw control or knob 286 by which the the fluid column between the pump and valve a motor upon pressure release by the pump, as

otherwise a hydraulic ramming or so-called hammer efiect wouldor might be produced upon the engine valve, with attendant disruption of smooth by reason of fective valve-closure. By thus throttling the fluid return flow upon pump pressure release, the fluid pressure on the valve motor is relatively gradually released, which thereby allows 9. correspondingly gradual or attenuated closure of the engine valve in a positive and relatively quiet manner,

As shown by Fig. 2, the valve device 43- comprises a casing 2l4 formed'to provide a fluid chamber 256 open at the casing end l, the open end of the chamber normally being closed by a threaded head or cap fluid leakage at the opening by a suitable gasket 254. In the intermediate zone of the chamber 256, the casing is formed to provide an annular bevelled shoulder 255 constituting a valve seat for the valve head 256 of a valve element 258, As controlled by valve element 258, the seat 255 may be said to define the main valve port of the device. The valve element which is of substantially tubular form bore or passage spidered rearwardly 259, and is externally flanged or from the valve head 256, is

movable longitudinally in chamber 256, being guided in such movement by engagement of its flanges with the casing wall portion 266 of reduced diameter near the inner end 262 of the chamber. A suitable compression spring 263 bearing at one end against the cap 252 and at its opposite end against a seat 264 on the valve head 256, serves to bias the valve element inwardly of the chamber 256 to seat the valve head on the chamber seat 255. The valve passage 259 at one end 266 thereof, is outwardly bevelled to form an aperture or port opening 261 for cooperation with the pointed end 268 of a needle-valve 216, formed of a thermally-sensitive material such as an aluminum alloy, for a purpose to appear, extending axially into' the chamber 256 through a casing guide passage 21l. The needle-valve passage 2" the resulting inef element 252 sealed against to provide a central longitudinal upward or leased for return through valve is internally threaded as at 215, to provide a threaded seat for an enlarged threaded portion 219 on the needle-valve 216. The threaded portion 219 may be provided by a separate collar suitably secured on the needle-valve 216, or as presently preferred, may be formed as an integral part of the valve. As will appear now, the needle-valve 216 is thus mounted for longitudinal adjustment through its threaded portion 219- in the threaded seat 215, efiected upon rotation-of the needle-valve element, so as to regulate the position of the port controlling end 268 thereof relative to the port 261 in the valve 258 when the latter is seated to close the main valve port 255.

Packing means 282 arranged in the casing 2l4 for preventing fluid leakage along the needle- I valve, is retained and suitably compressed thereabnormal wear of 284, ahand needle-valve may be manually rotated for effecting adjustment thereof. .In order to indicate externally of the valve device, the relative position of the valve tip 268 on needle-valve 216, and the port 261 controlled thereby, in any adjusted position of the needle-valve, a pointer 281 may be carried by the knob 288 for cooperation scale (not shown) 'on the outer end 288 of the casing. Additionally, a readily removable cover or ,cap 296 may be threaded onto the 288 for protecting the manual control end of the needle-valve.

Fluid communication between the valve chamber 256 at the inner end 262 tl erect, and the dischargepassage of the-pump is effected by the passage 2 the zone of the cap element 2| site side of the valve 258 and of chamber 256, is a fluid passage 292 extending from the chamber through a valve casing extension or lateral boss 294, and communicating with this passage is one end of the conduit 42 extending to valve motor 46. Connection of the conduit 42 to the casing extension 294 may be effected by a, suitable coupling 295' (Fig. 1). In addition, a relief port 296 is provided in a side wall portion of the valve 258, for a purpose which will appear presently.

Turning, now to the operation of the presently I. On the opponear the end,25l

described control valve, it will be observed that upon the suction or down stroke of the pump plunger, fluid under the pressure head afforded by the fluid supply source 21, will flow into the pump cylinder and therethrough to the valve chamber 256 through the passage 2l8. As the engine camshaft through cam I16 thereon, efiects delivery displacement of the pump plunger, the fluid ahead of the plunger will be placed under considerable pressure and will react against the valve 258 to displace the same against the bias of valve spring 263, for establishing full fluid discharge through the main port 255, .The fluid under pressure thus passing 255 and about valve element 258, and thence through conduit 42 to the engine valve motor 46, causes motor operation to open the engine valve.

Upon pressure release by the pump as the pump plunger approaches or attains the end of its delivery stroke, the fluid in conduit 42 will be redevice 43 and the pump, to the supply header 28. By reason of the restriction or throttling actionof the fluid return flow by the valve device 43, as will be presently described, sudden closure of the engine valve is eflectively prevented. If such were permitted, a rapid fluctuation or surging of the fluid column between the valve motor and pump, normally would be present, which would tend to produce a fluid hammer effect upon the motor and there through, upon the engine valve, tending to or per haps causing rapid partial opening and closure of the valve, with attendant disadvantages of the valve parts and a noisy valve operation.

Upon pressure release in the system, the spring 263 of valve assembly 43, displaces valve 258 to port-closing position (Fig. 2) relative to the main port 255. 'However, when this occurs the return flow of fluid to the pump is established at a greatly reducedor attenuated rate of flow, the valve passage 259 and the with an appropriate casing end l8 laterally in the valve casing 2 in,

through port through port opening 261. The restriction of fluid return-flow through p rt 261 as determined and controlled by the adjustself-adlustable .in

able needle-valve 210 through regulated projection of its port control tipen'd'268 in the bevelled port opening 261, thusresults in retarding closing-movement of the engine valve to an extent which corresponds relatively closely to the degree of return-flow restriction imposed by the coacting port 261 and needle-valve 270 in any adjusted position of the latter. tion of the fluid returned through the pump, normally will be by-passed-about the needle-valve controlled port 261 through the small lateral opening 296 in the serves principally-as apressure relief expedient, and serves also to dampen oscillations or surges, hence acts to prevent'local pressure build-up in the fluid return line from'the valve motor 40, in the event the needle-valve 210 is projected inwardly inadvertentlyor otherwise, to an extent such as to close thethrottling port 261 by the valve tip 268. In normal operation, the small leakage at the opening 296maybe readily compensated for by proper adjustment of the needlevalve. The ports 26'! and 296, because small in effective area; exhibit a marked effect in damping out line surges, particularly just after closing of the associated engine valve.

As hereinbefore indicated, the needle-valve 210 is formed from a thermally-sensitive material such as a suitable aluminum alloy, whereby to provide for automatic or self-adjustment in the return-flow throttlingfunction of the valve device, attained responsively to and in accordance with temperature differences in the actuating fluid employed in the system. For! example, during initial or starting operation of the engine embodying the present valve-actuating system, the valve-actuating fluid may be relatively cool and hence subject to a greater flow-inertia than obtains when the fluid is relatively warm or at a higher temperature. The thermal contraction of needle-valve 210 resulting from and in direct proportion .to the low temperature of the actuating fluid, thus aifords an increased'opening of the return-flow port 261 by the retractive displacement of theneedle-valve tip 268 relative to the port-opening 261, whereby to compensate for the greater flow-inertiaof the fluid throttled in its return-flow through the valve device. Normally and as a result of continued engine operation, the temperature of the actuating fluid may rise to an appreciable degree, in consequence whereof, the needle-valve element 210'will undergo thermal expansion in proportion to the rise in fluid temperature, to increase therebyand in corresponding degree, the return-flow restriction efiected by the needle-valve at the port 261.1 Accordingly, the needle-valve control is thus manually adjustable for regulating the return-flow throttling function of the valve device 43 in accordance with given conditions of engine operation, and any control setting of the needlevalve, to compensate for temperature differences of the actuating fluid latter as now appears, serves to equalize the throttled return-flow of. fluid through the valve device, as changes occur in the temperature of the actuating fluid.

During the throttled return flow of fluid from the valve motor, a certain portion of the fluid normally will be returned throughthe pump to the supply header 28, under a pressure determined in part, by' the pressure exerted on the fluid by the action of the valve motor 40 inclosing the engine valve. That portion of the Although a very small porvalve 258, the opening 296 valve body having an inlet seat in said body providing communication between the inlet and the outlet, a valve coacting t I Number inthe system. The

Name 2,004,904 Peo Junell, 1935 1,716,497 McCaskell- June 11, 1929 4. 10 Psachos Jan. 4, 1921 ,981,913 Fielden l. Nov. 27, 1934 2,144,861 Truxell Jan. 24, 1939 2,169,554 Buchanan Aug. 15, 1939 2,213,743 Miner Sept. 3, 1940 2,124,390 Anderson July 19, 1938 1,828,446 Rossman Oct.- 20, 1931 1,914,677 Shultz .i June 20, 1933 1,964,638 Kreidel June 26, 1934 1,972,170 Spencer Sept. 4, 1934' 1,972,907 ShaW' Sept. 11, 1934 FOREIGN PATENTS Number Country. Date 21,965 Dutch Oct. 15, 1930 562,923

fluid attaining the header 28 is, however, under suflicient pressure to maintain fluid flow along the header and into the return pipe 32, for return to the fluid source 21. r

The foregoing indicates thev character of hydraulic engine valve actuation attained by the presently described exemplary systemand the control function therein of the throttling valve device forming the subject of this invention. The control of valve closure afforded by the device .43 upon pump release of fluid pressure on the engine valve, is of particular advantage in the attainment of smooth, quiet and eflicient valve operation.- While the improved control valve assembly has been described and illustrated herein in association with a tem for engine cylinder valves, the application thereof is not so limited, as the device maybe readily employed in fluid pressure systems for actuating or controlling the actuation of mechanism other than valves and the like, and for the damping of unwanted oscillation in hydraulic systems generally. I

It will be understood, of course, that certain changes or modifications in the several elements of the control valve mechanism and in the arrangement thereof may be eifected without departing from the spirit and full intendedscope of the invention, as defined by the appended'claim.

I claim:

In a discharge valve assembly for a high pressure plunger type pump, a .structure forming a and an outlet, a valve with said seat, a spring urging the valve into closing position on said seat, said valve having a passage extending therethrough, and an adjustable throttling element mounted in, the inlet of the valve body coacting with said passage when the valve approaches seating position, the valve being so formed as to provide a second passage therein establishing a fluid flow through the by to prevent complete throttling element, or of thevalve.

valve at all times, whereobstruction of flow by the otherwise, in any position v HENRY SCHRECK REFERENCES CITED UNITED STATES PATENTS Date French Sept. 17, 1923 fluid impulse actuating syscontinuously open path for

Images