US1732812A - Governor - Google Patents

Description

A. T. KA$LEY GOVERNOR Filed June 9, 1924 2 sheets'-shee1; 1

H; Ilmsi'e INVENTOR I AW RN EV Oct. 22, 1929. KASLEY 1,732,812

GOVERNOR Filed June 9, 1924 2 Sheets-Sheet 2 N mm WITNESSES: 1 INVENTOR ATTORNEY Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE ELECTRIC & MANUFACTURING COMPANY, A

CORPORATION OF PENNSYLVANIA GOVERNOR Application filed June 9, 1924. Serial No. 718,984.

My invention relates to pressure-operated speed governors and has for an object to provide apparatus of the character designated which shall be of simple construction, reliable in operation and sensitive to varying load conditions.

More particularly, my invention has for its object to provide a spring loaded pressure-responsive element in a governing mechanism with a constant fluid-pressure load in addition to the spring, whereby a lighter spring may be employed, giving a greater range of movement to the pressure responsive element for a given variation in pressure.

Another object of my invention is to provide apparatus of the character designated with means for adjusting the constant fluidpressure load on the pressure-responsive element and thus to regulate the speed of the apparatus or machine being governed.

Apparatus made in accordance with my invention is illustrated in the accompanying drawings, in which 1F ig. 1 is a VlQW, in elevation, showing a steam turbine having my improved governor applied thereto; Fig. 2 is a sectional view of the governor drawn to a larger scale; and Fig. 3 is a fragmentary sectional View showing a simpler apparatus embodying my invention.

As is welhknown in the art, diliiculties have been encountered in the design of pressure-operated speed governors in providing a spring for acting against the pressure-responsive element in opposition to the var able governing pressure that would permit a suiiicient range of movement for a given variation in pressure and at the same time be of sufficient strength to withstand the rel atively high fluid-pressure necessary to operate the governing mechanism. The use of a single spring without any other compensat ing element to oppose the force of the fillld pressure has been found to be impractical due to its inordinate length.

1n the application of Henry F. Schmidt, Serial No. 604,033, filed November 29, 1922, (now Patent No. 1,533,766, issued April 14, 1925), for an improvement in governors, and assigned to the Westinghouse Electric &

trolled or operated thereby Manufacturing Company, there is illustrated and described a governor having a pressureresponsive element loaded with two springs, one being a relatively heavy spring of the floating type under substantially constant tension for a given adjustment and moving with the pressure-responsive element to its different positions, the other spring being relatively light and having one end fixed, constituting a scale spring for the pressureresponsive element, permitting a wider range of movement for a given variation in.

pressure.

My invention is particularly applicable to such a governor as is described in the application aforesaid and provides a simpler apparatus for obtaining a wide range of movement of the pressureresponsive element for a given variation in pressure. In accordance with my invention, the pressure-responsive element is loaded with a single spring to compensate for variations in pressure and in addition thereto, a constant fluid-pressure load is imposed thereon.v "By this means the spring employed may be of any scale to give the desired deflection tor a given variation in pressure. it also provide means for regulating the fluid-pressure load imposed whereby the speed of the apparatus governed may be regulated.

My invention is also applicable to the simpler i'orm of governing apparatus such as is employed for example, irt regulating the speed or small turbines, and may be employed in such apparatus with the part condirectly connected to the pressure-responsive element.

Referring now to the drawings for a better understanding of my invention, I show in Fig. 1 an elastic-fluid turbine 10, which is provided with an inlet valve 11, said inlet valve being operated by my improved governing apparatus at 12. The governing apparatus 12 acts in response to the pressure or fluid developed by a pump 13 or other suitable means driven by a shaft 14 of the turbine 10. Fluid is supplied by the pump 13 to the governor device 12 by means of a conduit 16 shown in Fig. 2 and fluid which is exhausted or leaks oil from the governor with a branch 28 of the conduit 18.

is returned by conduit 18, which communicates with a storage receptacle 19, which is in turn, connected by a conduit 21 with the inlet to the pump 13. The governor 12 comprises'a cylinder 22 within which is disposed a hollow operating piston 23. *The piston 23 is provided with ports 24 and 26 leading from-the interior thereof to its upper and lower faces, respectively. Between the ports 24 and 26 an exhaust port 27 leads from the interior of the piston 23 and is in all positions of the piston in communicatlipln e piston 23 is provided at its upper and lower ends with stem portions 29 and 31 which extend through covers 25 and of the cylinder 22 and form a fluid-tight joint therewith. Attached to the stem portion29 is a rod 32 for actuating the admission valve 11 through a lever 33. An upward movement of the piston 23 moves the admission valve 11 in a closing direction while a downward movement of the piston 23 moves the admission valve in an opening direction.

Disposed within the hollow operating piston 23 and controlling its movements is a hollow pilot valve 34. The pilot valve 34 is provided with ports 36 and 37 adapted to admit fluid under pressure to the ports 24 or 26. of the operating piston23 upon movement of the pilot valve. When the turbine is'running at a constant speed the ports 24 and 26 are covered by means of two annular shoulders 38 and 39 on the pilot valve 34. Between the annular shoulders 38 and 39 of the pilot valve 34 is a reduced portion 41, which is in communication at all times with the exhaust port 27 The lower end of the pilot valve 34 is open to permit fluid under pressure to pass to the interior thereof while the upper end is closed by means of a cap 42. The stem portion 31 of the-piston 23 extends downward through the cylinder cover 30 into a chamber 43 which serves as a pressure chamber for the pilot valve 34. In operation, fluid under pressure developed by the pump 13 is delivered to the chamber 43 and is therefore always present within the hollow'of the pilot valve 34. Upon an upward movement of the pilot valve 34, fluid under pressure passes through the ports 37 and 26 to the under side of the piston 23, forcing it upwardly. The

piston 34 moves upwardly until the port 26 is again covered by the shoulder 39 of the pilot valve 34. Upon a downward movement of the pilot valve 34, fluid under pressure is admitted through the ports 36 and 24 to the upper side of the piston 23 forcing it downwardly until the ports 24 are again covered. During its downward movement, fluid beneath the piston 23 passes through the port 26 around the reduced portion 41 of the valve 34 and thence to the exhaust through the port 27. During upward movement, fluid above the piston 23 passes through the port 24 around the reduced portion 41 and through the port 27 to the exhaust.

It will be seen from the drawings that the force of the fluid pressure acting against the pilot valve 34 tends to force it in an upward direction. To counteract this force acting against the pilot valve and to control this movement, I have provided a spring 76 and a chamber 86. The spring 76 is in tension between the cap 42 and an abutment 77 at the lower end of the chamber 43 and opposes the variable fluid pressure tending to force the pilot valve 34 upwardly. The pilot valve 34 is arranged to permit a restricted flow of fluid thereby into the chamber 86, which is formed in the upper stem portion 29 of the operating piston 23. This may be done by providing a restricted opening 87 in the cap 42, as shown, or by loosely fitting valve 34 in piston 23.

At the upper end of the chamber 86 is an outlet 78, through which fluid flowing by the valve 34 is permitted to pass to a passage 79, from whence it passes to sump 81 and thence through a conduit 82 and the drain conduit 18 to the fluid reservoir 19. Controlling the flow of fluid through the outlet 78 is a valve 83. The valve 83 is weighted, or biased as by a spring 84, having an adjustable abutment 85. By this means, the fluid in the chamber 86, above the valve 34 in passing through the outlet 78 has pressure imposed thereupon, off-setting a certain part of the pressure acting to force the valve 34 in an upward direction. The valve 34, therefore, is actuated in an upward direction by the vari'able fluid pressure developed by the pump 13 and in a downward direction by the spring 76 aided by the constant pressure imposed upon the fluidwithin the chamber 86 above the valve 34. The spring 76 may be termed a scale or governing spring; that is, it is a spring which is variably deflected and whose scale determines the position of the pilot valve in accordance with the variable fluid pressure acting thereon. It will be apparent that any desired pressure may be imposed upon the fluid above the valve 34 and that a spring 76 may be thereby selected to give the desired range of movement for a given variation in pressure.

The operation of the apparatus so far described is as follows: Fluid under pressure is developed by the pump 13, driven by the shaft 14, of the turbine 10. As the speed of the turbine varies, a pressure varying as a function of the speed is developed. This fluid under variable pressure is conveyed to the chamber 43 and to the interior of the pilot valve 34. The valve 34 permits a continuous restricted flow of fluid thereby which passes to the outlet 78 in the upper end of the chamber 86. The loaded valve 83 controls the flow and imposes a constant pressure upon the fluid passing through the outlet and thus oifsets a part of the variable pressure acting to force the valve 34 in an upward direction. The spring 76 exerts a force proportional to its deflection in opposition to the variable pressure beneath the pilot valve 34 to offset the remainder of said variable pressure. If the turbine is operating at a normal speed the parts assume the position shown in Fig. 2. lipon an increase in speed and a consequent increased pressure beneath the valve 34, the pilot valve 34 moves upwardly, further tensioning the spring 7 6 to compensate for the increased force exerted by the pressure of the fluid. As the loaded valve 83 maintains a constant pressure above the valve 34 the upward movement thereof is opposed both by the spring 76 and by the constant fluid pressure above it. Upward movement of the pilot valve 31 is followed by an upward movement of the piston 23 and a movement of the admission valve 11 in a closing direction as already described.

Upon a decrease in speed of the turbine and a consequent decrease in pressure developed by the pump 13, the spring 76 aided by the offsetting effect of fluid pressure above the valve 3-;l, forcesit in a downward direction, followed by the piston 23, which movement opens the admission valve 11 wider.

To regulate the speed of the turbine, the adjustable abutment 85 of the spring 84 is moved to increase or decrease the pressure exerted by the spring and consequently to increase or decrease the pressure imposed upon the fluid above the valve 34. By increasing this pressure. a higher speed and higher variable pressure is required to operate the governor mechanism. By reducing the pressure above the valve 34. a lower speed and a lesser variable pressure is required to operate the governor mechanism to close the admission valve 11.

In Fig. 3 is shown a simpler form of governing apparatus embodying my invention, comprising a cylinder 61 having an inlet 62 for variable fluid pressure, a piston 63 against which the variable fluid pressure acts to force it upward and a spring 64 opposing the fluid pressure beneath the piston. The piston 63 is "Eonnected by a rod 66 to a'lever 67, fulcrumed at 68, which controls the movements of an admission valve 69. The piston 63 is arranged to permit a flow of fluid thereby which passes through an outlet 71 controlled by a weighted valve 72 and thence out through a conduit 73.

The operation of apparatus made in accordance with this embodiment is similar to that described for the pilot valve 34. in Fig. 2 and need not be repeated. The only difference between the embodiment illustrated in Fig. 3 and that illustrated in Fig. 2 consists in connecting the pressure-responsive element d1- rectly to the part to be controlled without the interposition of a second piston to exert the force necessary for governing, in other words, without the interposition of a relay action.

From the foregoing, it will be apparent that I have invented a fluid-pressure governor wherein the pressure-responsive elementis opposed by a spring and by a predetermined constant fluid pressure, whereby a spring of lighter scale may be employed, and the pressure-responsive element have a wider range of movement for a given variation in pressure.

IVhile I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior artor as are specifically set forth in the appended claims.

What I claim is:

1. In a governing mechanism, the combination ofa piston operated by fluidunderpressure, a pilot valve controlling the operations of said piston and actuated in one direction by variable fluid pressure, scale spring means associated with the valve and opposing the variable fluid pressure, and means associated with the resilient means for imposing a fluid pressure resistance to the variable fluid pressure to enable the use of spring means of suitably light scale.

2. In a governing mechanism, the combination of a piston operated by fluid under pressure, a pilot valve controlling the operation of said piston and actuated in one direction by variable fluid pressure, scale spring means associated with the valve and opposing the variable fluid pressure, and means associated with the resilient means for imposing a predetermined fluid pressure resistance to the variable fluid pressure to enable the use of spring means of suitably light scale.

3. In a governing mechanism for a prime mover, the combination of means for developing fluid pressure varying as a function of the speed of the prime mover, an operating piston actuated by the variable fluid pressure, a pilot valve controlling the movements of the operating piston, said pilot valve being actuated in one direction by the variable fluid pressure, scale spring means for actuating the pilot valve in the opposite direction, and means for imposing a constant fluid pressure on the pilot valve in opposition to the variable fluid pressure to enable the use of spring means of suitably light scale.

4. In a governing mechanism, the combination of an operating piston actuated by variable fluid pressure, a pilot valve controlling the movements of the operating piston, said pilot valve being actuated in one direction by the variable fluid pressure, a scale spring associated with the pilot valve for providing a variable resistance to the fluid pressure, and means associated with the spring for imposing a predetermined constant fluid pressure resistance to the variable fluid pressure to enable the use of a spring of suitably light scale.

5. In a governing mechanism fora prime mover, the combination of means for developing fluid pressure varying as a function of the speed of the prime mover, a pilot valve actuated in one direction by the variable fluid pressure and in the other direction by a scale spring, means comprising'fluid pressure for off-setting a predetermined part of the force exerted on the pilot valve by the variable fluid pressure to enable the use of a spring of suitably light scale, and an operating piston actuated by fluid pressure and'controlled by the pilot valve.

6. In a governing mechanism for a prime mover, the combination of means for developing fluid pressure varying as a function of the speed of the prime mover, a pilot valve actuated in one direction by the variable fluid pressure and in the other direction by a scale spring, means for imposing upon the pilot valve a predetermined constant fluid pressure in opposition to the variable fluid pressure to enable the use of a spring of suitably light scale, and an operating piston actuated by fluid pressure and controlled by the pilot valve, said operating piston following the movements of the pilot valve.

7. In a fluid-pressure actuated governor for an elastic fluid motor having an admission valve, the combination of means for developing fluid pressure varying as a function of the speed of the elastic fluid motor, a cylinder having an operating piston disposed therein actuated by fluid pressure for controlling the admission valve, a valve controlling the operation of said piston, said valve being actuated in one direction by the variable fluid pressure and biased in the opposite direction by a spring, and permitting a restricted flow of fluid thereby to an outlet, and means disposed within the outlet for imposing a pressure on the fluid flowing by the valve and through said outlet, which pressure is exerted on the valve in opposition to the variable fluid pressure.

8. A variable fluid-pressure actuated governor mechanism comprising a hollow piston closed at one end and operated by fluid pressure, a pilot valve within the piston and actu-' ated by the variable fluid pressure, a spring within the pilot valve and attached at one end to a fixed abutment and at the other end to the pilot-valve for opposing the variable fluid pressure, said pilot valve permitting a restricted flow of fluid thereby into the closed 'end of the operatin piston, and an adjustable spring weighte valve for controlling the flow of fluid from the closed end of the operating piston and for imposing a pressure thereon, which pressure is exerted on the pilot valve in opposition to the variable fluid pressures.

9. In avariable fluid-pressure governing apparatus for controlling the admission of fluid to a prime mover, the combination oi means providing a fluid pressure varying as a function of an operating condition of said prime mover, an element actuated in one direction by said variable fluid pressure, means for applying other fluid pressure to said element in opposition to the first-mentioned fluid pressure, a scale spring acting on said element to oppose the difference of said fluid pressures, and means controlled by said element for controlling the admission of motive fluid to the prime mover.

10. In a variable fluid-pressure governing apparatus for controlling the admission of fluid to a prime mover, the combination of means providing a fluid pressure varying as a function of an operating condition of said prime mover, an element actuated in one direction by said variable fluid pressure, means for applying other fluid pressure to said element to offset a part of the force exerted on said element by the variable fluid pressure, a spring acting on said element to offset the remainder of said force, and means controlled by said element for controlling the admission of motive fluid to the rime mover.

11. In a variable fliiid-pressure governin" apparatus for controlling the admission 0 fluid to a prime mover, the combination of means providing a fluid pressure varying as a function of an operating condition of said prime mover, an element subjected on one side to the variable fluid pressure, means for providing and regulating a second fluid pressure derived from the variable fluid pressure, said second fluid pressure being exerted on the opposite side of said element, a spring for biasing said element in opposition to said variable fluid pressure, and means controlled by said element for controlling the admission of motive fluid to the prime mover.

12. In a fluid-pressure governing apparatus for a prime mover, means for developing fluid-pressure varying with the speed of the prime mover, an element actuated in one direction by the variable fluid pressure, means for applying a fluid pressure on said element in opposition to the first mentioned fluid pressure and for regulating the second-mentioned fluid pressure, a single spring exerting a force on said element in opposition to the first-mentioned fluid pressure, and means controlled by said element for controlling the admission pressure in one direction and to the pressure in said enclosed space in the opposite direction, and effecting a governing action on said machine, and a spring biasing said pressureresponsive means in opposition to the variable fluid pressure.

14;. A fluid pressure governor for a prime mover comprising means for developing a fluid pressure varying as a function of the speed of the prime mover, a pressure-responsive element subjected to said variable pressure, *means providing an enclosed space, means permitting a restricted floW of fluid from said variable pressure into the enclosed space, means controlling the escape of fluid from said enclosed space and imposing a back pressure on, the fluid therein, said back-pressure acting on the pressure-responsive element in opposition to said variable fluid pressure, a spring for biasing said'pressure-responsive element in opposition to the variable fluid pressure, and means controlled by the pressure-responsive element for controlling the admission of motive fluid to the prime mover.

15. In a fluid pressure governor for a prime mover, the combination of means for developing a fluid pressure varying as a function of the speed of the prime mover, a pressure-responsive element subjected to said variable pressure, a spring biasing said element in opposition to the variable fluid pressure, means providing an enclosed space, means permitting a restricted flovv of fluid into said enclosed space, a valve controlling the escape of fluid from said space and imposing a back pressure on the fluid therein,

said valve being biased in opening direction by said back pressure and in closing direction by a spring, and means for controlling the force exerted by said last-mentioned spring, the fluid pressure in said enclosed space acting on said pressure-responsive ele ment in opposition to said variable fluid pressure, and means controlled by said pressure responsive element for controlling the admission of motive fluid to the prime mover.

16. In a fluid pressure governor for controlling an operated member in response to a variable force, the combination of means providing an enclosed space, means provid ing a restricted flow of fluid 1nto said space, a valve controlling the escape of fluid from said space and imposing a pressure on the fluid therein, said valve being biased in opening direction by the pressure in said space and in closing direction by a spring, means for adjusting said spring, a pressure-responsive element subjected to said variable force and to the pressure in said enclosed space, and means controlled by the pressure responsive element for actuating the operated member.

17 In a governing apparatus for controlling an operated member in response to a variable fluid pressure, the combination of an element subjected on one side to the variable fluid pressure, m'eans providing an enclosed space, means providing a restricted floW of fluid into said enclosed space, a valve for controlling the escape of fluid from said enclosed space and imposing a pressure on the fluid therein, the pressure in said enclosed space acting on said pressure-responsive element in opposition to the variable fluid pressure, a spring biasing said element in opposition to one of the fluid pres- .sures acting thereon, and means controlled by the pressure-responsive element for actuating the operated member.

18. In a fluid pressure governing mechanism for a prime mover, the combination of means for developing a fluid pressure varying as a function of the speed of the prime mover, means providing an enclosed space, means providing a restricted flowof fluid into said enclosed space, a valve for controlling the escape of fluid from said enclosed space and imposing a pressure on the fluid therein, a pressure-responsive element subjected to the variable fluid pressure in one direction and to the pressure in said enclosed space in the other direction, and means controlled by the pressure-responsive element for controlling the admission of motive fluid to the prime mover.

19. In a fluid pressure governor for a prime mover, the combination of means for developing a fluid pressure varying as a function of the speed of the prime mover, a pressure-responsive element subjected to said variable fluid pressure, means for applying a substantially constant fluid pressure to said element in opposition to the variable fluid pressure for cit-setting a portion of the load thereof, a relatively light spring for oflsetting the remainder of said load and providing relatively great deflections upon variations in fluid pressure, and means controlled by said element for controlling' the admission of motive fluid to the prime mover.

20. In a fluid pressure governor for a prime mover, the combination of means for developing a fluid pressure varying as a function of the speed of the prime mover, a pressure responsive element subjected to said variable fluid pressure, means for applying a second fluid pressure to said element in opposition to the variable fluid pres sure for offsetting a portion of the load thereof, means for controlling said second fluid pressure, a relatively light spring for offsetting the remainder of said load and providing relatively great deflections upon variations in fluid pressure, and means controlled by said element for controlling the admission of motive fluid to the prime mover.

21. In a fluid pressure governor for a prime mover, the combination of means providing a fluid pressure varying as a function of the speed of the prime mover, means including and controlled by an element subjected to said fluid pressure for controlling the admission of motive fluid to the prime mover, means for applying other fluid pressure to said element to offset, in part, the variable fluid pressure, and sprlng means acting on said element to provide variable resistance to the variable fluid pressure, the deflection of said spring means being proportional to the difl'erence of said fluid pressure to provide a force to balance the same.

In testimony whereof, I have hereunto subscribed my name this. first day of May ALEXANDER T. KASLEY.

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