US3776266A

US3776266A - Engine starter valve

Info

Publication number: US3776266A
Authority: US
Inventors: J Bass; R Smith
Original assignee: Parker Hannifin Corp
Current assignee: Parker Intangibles LLC
Priority date: 1972-09-22
Filing date: 1972-09-22
Publication date: 1973-12-04
Anticipated expiration: 1990-12-04

Abstract

An engine starter valve for regulating engine starter air pressure to thereby control air flow in connection with the starting of aircraft turbine engines and the like characterized in that it has a main air flow control valve member which is actuated by a double acting actuator; a pressure sensor which senses air pressure downstream of the main valve member; and a modulator or pilot valve which is actuated by the sensor and which modulates the air flow from the upstream side of the main valve member to create differential pressure on opposite sides of the double acting actuator thus to move the main valve member to increase or decrease air flow through the valve. The valve herein is further characterized in that the modulator circuit embodies a pressure rise rate control valve therein to limit to desired value the rate of increase of air pressure downstream of the main valve member.

Description

United States Patent Ba s et al, Dec. 4, 1973 l ENGINE STARTER VALVE 57 ABSTRACT [75] Inventors: James H. Bass, Irvine; Robert P. An engine starter valve for regulating engine starter Smith, Newport Beach, both of air pressure to thereby control air flow in connection C lif. with the starting of aircraft turbine engines and the like characterized in that it has a main air flow control [73] Asslgnee: parker'uanmfin Corporawn valve member which is actuated by a double acting ac- Clevcland Ohio tuator'; a pressure sensor which senses air pressure [22] Filed: Sept. 22, 1972 downstream of the main valve member; and a modulator or ilot valve which is actuated b the sensor and [21] Appl 291236 which i nodulates the air flow from th e upstream side of the main valve member to create differential pres- [52] U.S. Cl. 137/489 sure on opposite sides of the double acting actuator [51] Int. Cl. Fl6k 31/383 thus to move the main valve member to increase or [58] Field of Search 251/58; 137/489 7 decrease air flow through the valve. The valve herein is further characterized in that the modulator circuit [56] References Cited embodies a pressure rise rate control valve therein to UNITED STATES PATENTS limit to desired value the rate of increase of air pres- 2,31s,912 4 1943 Udale 137/489 x sure downstream the main Valve member- 3,l36, 333 6/1964 GliSWOid 137/489 Claim, 8 Drawing Figures Primary Examiner-J-lenry T. Klinksiek Attorney-Walter Maky PATENTED DEC 4 I975 SHEET 2 BF 2 l n I l In one form of widely used regulator a spring loaded diaphragm or piston has one side thereof exposed to regulated pressure downstream of the main valve member and is so arranged that movement of the diaphragm or piston upon decrease or increase of regulated pressure actuates the main valve member so as to maintain desired regulated pressure. One disadvantage of this type of regulator is that the regulated pressure decreases with increased flow because of progressive decrease in spring load during the opening of the main valve member. Other types of regulators are well known in the art, such as, for example, the pilot operated type in which opposite sides of the main valve actuator diaphragm or piston is exposed to regulated pressure and control chamber pressure, the control chamber pressure being maintained at desired value by means of a pilot regulator.

Known forms of regulators, as aforesaid, are not generally sensitive to small changes in regulated pressure because the correspondingly small changes in main valve actuating forces must first overcome flow and friction forces before the main valve member can partake of opening or closing movements.

In engine starting applications, it is essential that there be accurate control of the starter acceleration and that the engine starter control valve be sensitive to small changes in the controlled pressure downstream of the main control valve member but yet provide large forces for controlling the position of the main valve member to satisfy changes in flow demand, thereby to minimize the effect of flow and friction forces.

In such engine starting application it is also desirable to limit the pressure rise rate to achieve accurate control of starter acceleration by decreasing the rate of opening of the main control valve member, this being a feature not embodied in known regulators.

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an engine starter valve which accurately regulates the pressure to thereby control the flow of engine starter air.

It is another object of this invention to provide a valve of the character indicated in which a pilot modulator circuit including fixed orifices and variable area orifices creates different pressures on the opposite sides of a double acting actuator for the main control valve, the 1 pilot circuit including a pressure sensor which senses and accurately controls air pressure downstream of the main control valve member.

It is yet another object of this invention to provide a valve of the character indicated which has associated with the pressure sensor of the modulator, a pressure rise rate control valve to limit the rate of air pressure increase downstream of the main control valve member to apredetermined value.

Other objects and advantages will become apparent as the following description proceeds.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view of apreferred form of engine starter valve showing in cross-section the main valve member which controls air flow in the turbine starter circuit.

FIG. 2 is an end elevation view as viewed from the left hand side of FIG. 1;

FIG. 3, 4 and are cross-section views taken substantially along the lines 33, 4-4, and5--5 of FIG. 1;

FIG. 6 is a cross-section view taken substantially along'the line 66 of FIG. 3;

FIG. 7 is a schematic diagram of the engine starter valve shown in FIGS. 1-6; and

FIG. 8 is a schematic diagram similar to FIG. 7 except illustrating a modified form of engine starter valve.

DETAILED DESCRIPTION OF THE. PREFERRED EMBODIMENTS Referringnow in detail to the drawing and first to FIGS. 1-7 thereof, the engine starter valve 1 comprises a valve body 2 having an inlet 3 and an outlet 4, and a main valve member 5 movable in said body 1 to regulate the flow of air from the inlet 3 to the outlet 4, said main valve member 5 herein illustratively being a butterflyvalve member which is turned in the body 1 between open and closed positions as by means of the link 6 clamped to the shaft 7 thereof which link 6, in turn, is connected to the double acting actuator piston 8 by the link 9 and pivots 10 and 11. The shaft 7 of the butterfly valve member extends through the upper housing 12 and has a visual indicator 14 to indicate the fully closed and opened positions of the butterfly valve member 5 and the intermediate positions where flow is controlled according to demand. The actuator piston 8 is biased by spring 15 in a direction tending to hold the main valve member Sin closed position and reciprocates in a cylinder assembly 16 having

passages

17 and 18 leading to opposite sides of the piston. The end of the actuator piston 8 is engaged by the lever 19 of a position switch 20 which is closed when the main valve member 5 is 6 or more open.

As shown in FIGS. 1, 3, 6 and 7, the valve body 1 has a passage 21 exposed to air pressure upstream of the main valve member 5'via a filter 23, such upstream air pressure being conducted to the

actuator chambers

24 and 25 via the

passages

21, 17 and 18 and the

fixed orifices

26 and 27. The air pressure in the

passages

17 and 18 ismodulated by means of variable area orifices28 and 29 through which air is variably bled when the solenoid-operated" bleed valve 30 is energized as shown in FIG. 7.-When the solenoid 31 is dc-energized, the bleed valve 30 is in closed position as shown in FIG. 5 whereby equal pressures in the

passages

17 and 18 will effect movement of the actuator piston 8 to close the main valve member 5 by the influence of pressure on the larger area of the piston 8 in. chamber 24 and the effect of the biasing spring 15. I

The modulator or pilot valve 32 is moved to vary the area of

orifices

28 and 29 by a pressure sensor 34 which senses air pressure downstream of the main valve member 5 through the passage 36 and tube 37.

Referring now to FIGS. 4 and 7 when the main valve member 5 is in closed position, the variable area orifice 28 will be closed or substantially closed by the pilot valve 32 and the variable area orifice 29 will be open owing to lack of downstream pressure acting on the diaphragm 38 of the sensor 34 whereby, when the solenoid 31 is energized to open the bleed valve 30, the pressure inthe actuator chamber 24 will be decreased relative to the pressure in the chamber 25 and when the differential pressure is of predetermined magnitude, the actuator piston 8 will be moved in a direction to open the main valve member 5 with attendant increase in downstream pressure until the downstream pressure is sufficient to actuate the diaphragm 38 against the adjustable loading spring 39 thus to permit movement of the modulator or pilot valve 32 to increase the area of the variable area orifice 28 and to decrease the area of the other variable area orifice 29 until the pressures in the chambers 24 and are so related as to satisfy the flow demand of the starter circuit.

In the operation of the engine starter valve 1 herein in its regulating mode, air pressure downstream of the main valve member 5 acting on the area of the diaphragm 38 via the passages and 41 positions the modulator 32 so that the flow from the

chambers

24 and 25 of the actuator 8 establishes a pressure differential in the

chambers

24 and 25 so as to position the main valve member 5 to satisfy the flow demand of the system. The pressure control in the

chambers

24 and 25 of the actuator piston 8 is achieved by a flow balance between the fixed

inlet orifices

26 and 27 which are located upstream of the modulator 32 and the

variable area orifices

28 and 29 defined between the modulator 32 and the

seats

42 and 43 at opposite ends thereof.

As evident, a minute change in the controlled downstream pressure produces a minute change in the position of the modulator 32 which in turn creates a large change in the actuator piston 8 differential pressure in

chambers

24 and 25. A large force is thus made available to reposition the main valve member 5 to satisfy such minute change in flow demand. This power amplification or high gain in the control loop of the 'valve 1 is desirable in order to achieve accurate regulation by overcoming static and dynamic friction forces and flow forces on the main valve member 5. By way of example, the actuator area 25 and the load of the biasing spring 15 may be arranged to permit the main valve member 5 to open fully at an inlet pressure of 35 PSIG.

The pressure rise rate control valve 45 herein included limits downstream pressure rise rate to less than 22 PSI/sec. The diaphragm sensor 46 is set to uncouple the modulator 32 from the main pilot valve sensor 34 at pressure rise rates exceeding for example, 18 PSI/- sec.

Both sides of the rate control diaphragm 46 are connected to the downstream sensing passage 36 and in the case of the upper side of the rate control valve diaphragm 46 as viewed in FIG. 7 or the right hand side of said diaphragm 46 as viewed in FIG. 4, has restricted communication as through the sliding fit of the stem 47 in the bore of the housing 12 to create a time delay for filling and exhausting the chamber 48. The other side of the rate control diaphragm 46 has unrestricted communication with the downstream sensing passage 36 and therefore responds to downstream. pressure instantaneously. When the differential pressure across the rate control diaphragm 46 exceeds 3 or 4 PSIG, the diaphragm 46 moves against its small spring 49 preload independent of the pilot valve sensor 34 and drives the modulator 32 in the reverse direction. This feedback movement arrests the decaying pressure in the actuator chamber 24 and increases it to a value required to decrease the speed of valve opening and hence the downstream pressure to less than 18 PSI/sec. Since a dynamic condition exists, the downstream pressure will continue to increase but it cannot exceed the allowable rise rate. In other words, the rate control valve 45 will not tolerate a condition in which the pressure on its lower chamber exceeds by 3 or 4 PSIG the pressure on its upper chamber 48. Once the downstream pressure is within the regulation band, the rate control valve 45 normally does not operate. The rate control valve 45 will only control when its differential pressure exceeds 3 or 4 PSIG and the pressure rise rate exceeds 18 PSI/- sec. The rate control valve 45 functions in the manner of a viscous dashpot damper for all step increases above 4 PSI.

When the solenoid 31 is de-energized the bleed valve 30 will close to allow the

actuator chamber

24 and 25 pressures to equalize at the upstream value. The projected pressurized area of the actuator piston 8 exposed to pressure in chamber 24 and the actuator piston spring 15 preload then moves the main valve member 5 to closed position. With the solenoid 31 energized, the bleed valve 30 will open and the main valve member 5 will be actuated to fully open position at inlet pressures greater than 35 PSIG for example, and will be in the regulating mode at inlet pressures above PSIG.

The engine starter valve 55 shown in FIG. 8 is substantially the same as that shown in FIGS. l-7, except that the pressure rise rate control valve 45 has been omitted and a restrictor valve 56 has been incorporated in association with the actuator piston 8 to assure initial slow movement of the actuator piston 8 and main valve member 5 to control movement at desired rate to increase or decrease the air flow rate through the valve 55. This is accomplished by the restricted flow opening 57 in the restrictor valve 56 which controls the rate of movement of the actuator piston 8 in opposite directions, i.e., the pressure rise rate in the chamber 25 for opening of the main control valve member 5 is restricted by the restricted'passage 57 in the restrictor valve 56, and conversely, the downward movement of the actuator piston 8 for effecting closing movement of the main valve member 5 is controlled by the restricted exhaust from the chamber 25 via the restricted passage 57.

I therefore, particularly point out and distinctly claim as my invention:

1. A valve comprising a body having a passage for flow of fluid therethrough; a main valve member movable in said passage to control flow of fluid therethrough; a double acting actuator operatively connected to said main valve member to move the latter as aforesaid; said body having passage means in fluid communication with said passage upstream of said main valve member and with chambers on opposite sides of said actuator whereby said actuator may be moved in opposite directions by differential fluid pressures in said chambers; a pilot valve member movable in said body to selectively differentially vent said passage means through a vent passage in said body thereby to establish difierential fluid pressures in said chambers whereby said main valve member is moved in opposite directions by said actuator to increase or decrease fluid flow through said passage; and a pressure sensor in fluid communication with said passage downstream of said main valve member operative to move said pilot valve member as aforesaid in response to fluctuations in fluid pressure in said passage downstream of said main valve member thereby to maintain a substantially constant fluid pressure in said passagedownstream of said main valve member.

2. The valve of claim 1 wherein said passage means has fixed orifices therein upstream of the respective chambers and upstream of said pilot valve member.

3. The valve of claim 1 wherein the opposite sides of said actuator exposed to fluid pressure in the respective chambers are of unequal area so that said main valve member is moved to passage closing position upon equalization of fluid pressures in said chambers.

4. The valve of claim 3 wherein a bleed valve in said body is operative to open said vent passage for selective differential venting of said passage means by said pilot valve member and to close said vent passage to effect equalization of fluid pressures in said chambers.

5. The valve of claim 4 wherein spring means acting on said actuator further assists in movement of said main valve member to passage closing position when said vent passage is closed by said bleed valve.

6. The valve of claim 1 wherein a bleed valve in said body is operative to open said vent passage for selective differential venting of said passage means by said pilot valve member and to close said vent passage for equal ization of fluid pressures in said chambers; and wherein spring means acting on said actuator moves said main valve member to passage closing position when said vent passage is closed by said bleed valve.

7. The valve of claim 6 wherein said bleed valve is solenoid operated and closes said vent passage except when the solenoid thereof is energized.

8. The valve of claim 1 wherein said main valve member is a butterfly valve member having a shaft portion rotatable in said body; and wherein said actuator comprises a piston operatively linked to said shaft portion to turn the latter in opposite directions responsive to reciprocation of said piston. I

9. The valve of claim 8 wherein said shaft portion has visual indicating means thereon externally of said valve body to denote the position of said butterfly valve member in said passage.

10. The valve of claim 1 wherein a pressure rise rate control means is exposed to fluidl pressure in said passage downstream of said main valve member and is operatively connected to said pilot valve member to retard decay of fluid pressure in one of said chambers in response to rapid increase in fluid pressure downstream of said main valve member.

11. The valve of claim 10 wherein said control means has a lost motion connection with said pressure sensor to respond to predetermined rise rate of fluid pressure in said passage downstream of said main valve member.

12. The valve of claim 10 wherein said body has dashpot means to retard the rate of actuation of said control means.

13. The valve of claim 1 wherein said passage means has restrictor means to control the movements of said actuator.

14. The valve of claim 13 wherein said restrictor means is in the flow path into the chamber which effects opening of said main valve member by said actuator and from said chamber when said main valve member moves in passage closing direction.

Claims

1. A valve comprising a body having a passage for flow of fluid therethrough; a main valve member movable in said passage to control flow of fluid therethrough; a double acting actuator operatively connected to said main valve member to move the latter as aforesaid; said body having passage means in fluid communication with said passage upstream of said main valve member and with chambers on opposite sides of said actuator whereby said actuator may be moved in opposite directions by differential fluid pressures in said chambers; a pilot valve member movable in said body to selectively differentially vent said passage means through a vent passage in said body thereby to establish differential fluid pressures in said chambers whereby said main valve member is moved in opposite directions by said actuator to increase or decrease fluid flow through said passage; and a pressure sensor in fluid communication with said passage downstream of said main valve member operative to move said pilot valve member as aforesaid in response to fluctuations in fluid pressure in said passage downstream of said main valve member thereby to maintain a substantially constant fluid pressure in said passage downstream of said main valve member.

6. The valve of claim 1 wherein a bleed valve in said body is operative to open said vent passage for selective differential venting of said passage means by said pilot valve member and to close said vent passage for equalization of flUid pressures in said chambers; and wherein spring means acting on said actuator moves said main valve member to passage closing position when said vent passage is closed by said bleed valve.

8. The valve of claim 1 wherein said main valve member is a butterfly valve member having a shaft portion rotatable in said body; and wherein said actuator comprises a piston operatively linked to said shaft portion to turn the latter in opposite directions responsive to reciprocation of said piston.

10. The valve of claim 1 wherein a pressure rise rate control means is exposed to fluid pressure in said passage downstream of said main valve member and is operatively connected to said pilot valve member to retard decay of fluid pressure in one of said chambers in response to rapid increase in fluid pressure downstream of said main valve member.