US1814631A

US1814631A - Fluid pressure governor

Info

Publication number: US1814631A
Application number: US285673A
Authority: US
Inventors: James L Ray
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1928-06-15
Filing date: 1928-06-15
Publication date: 1931-07-14
Anticipated expiration: 1948-07-14

Description

July 14, 1931. 11.1w 1,814,631

FLUID PRESSURE GOVERNOR Filed June 15, 1928 V G3 3 62 g 52 39 1'1 1 Q32 l5 4 QE 4 49 29 4 55 45 a 31 51 4 3 4 5| 4| z u I 11 I 5 3 1:: 2: a: s2,

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WITNESSE I 4 J I I E v 6. I n Y I fi BY QXPQ ATTORNEY Patented-Jul 14, 1931 UNITED sTATEsrAT'ENT OFFICE v JAMES L. RAY,'OI' SWARTHMOBE, PENNSYLVANIA, ASSIGNOR T WESTINGI-IOUSE ELEC- TRIC & MANUFACTURING COMPANY,

A CORPORATION OF PENNSYLVANIA FLUID rnnssunn GOVERNOR Application filed June 15,

My invention relates to governors, more particularly to fluid-pressure governors for prime movers-and it has for its ob ect to provide a governor affording improved reg- Inaccordance with my invention I pro-.

deflection.

I also. provide, in accordance with my in: vention, a pressure transformer of simple and inexpensive design.

Apparatus exemplifying my invention is.

illustrated in the accompanying drawings, in which: I

Fig. 1 is a diagrammatic view of my governor as applied to a prime mover, with the parts thereof shown in section; and

Fig. 2 is a sectional view of a modified form of pressure transformer.

Referring to the drawings in detail, I show a turbine 10 having a steam chest 11 and a shaft 12. A pump is provided which includes a casing 13 andan. impeller 14 mounted 1928. Serial No. 285,673.

directly on the shaft 12. The pump is supplied with fluid, preferably a liquid, such as lubricating oil from a reservoir 64 through a conduit 65, and'provides a fluid ressure varying as the square of'the spec of the shaft 12, as is well known of centrifugal pumps. The pressure developed by the pump is transmitted through a conduit 15 to a pressure-transforming device 16.

The device 16 includes a casing 17 having a partition 18 therein dividingthe easing into two compartments 19 and 2], Abore portion 22 is formed in the partition 18, and loosely fitted in this bore portion is a piston portion 23 which is an integral extension of a pressure-relief valve 24. Asmall passage 25 also extends through the partition 18 and is disposed in close proximity to the bore portion 22. An adjustable needle valve 26 provides. a restricted orifice 27 in thepassage 25. The conduit 15 communicates with the chamber 21 of the pressure transformer and supplies governing fluid pressure thereto, which pressure is effective on thelower end of the piston portion 23.

The passage 25 communicates with an annular groove 29 in. the partition 18, said groove being concentric with the bore 22. The valve 24 has a flange 31, which seats on the partition 18 outwardly of the groove 29, and which forms a recess 59 with the piston portion 23'. The valve 24 is biased to closed position by a compression spring 32, interposed between the valve and a spring holding member 62. The position of the latter may be adjusted by a screw 63 to vary the force exerted by the spring 32. A passage 33 is formed in the partition 18 and provides communication between the groove 29 and a conduit 34.

The conduit 15 communicates with a branch conduit and the conduits and 35 communicate with a relay valve casing 36 I which returns the discharged fluid to the reservoir 64. The casing is further provided with ports 43 and 44, communicating with the 11 per and lower ends, respectively, of a cylin er 45 in which isdisposed an operating piston 46, The pistonf46 is connected to and operates the valves of the steam chest 1 1 through any suitable means, such means being here shown as a rod 47.

A pilot valve 48 is disposed and operates within the cylindrical casing 36. The pilotvalve is provided with piston portions 49 and \51 which normally covertheports 43 and 44, respectively. Piston

portions

52 and 53 are also provided at the ends of. the pilot valve beyond the discharge ports 39 and-41,..re-

specti'vely; The pilot valve 48 is formed with a hollow interior and is closed at the upper end. A tension spring 54 isdisposed within the hollow interior, having one ,end secured to the closed upper end-of the pilot valve and having its other end secured to the upper end of a stem 55, which extends through thelower end of the casing. The

stem 55 is connected at its lower end to a lever-- 56 intermediate the ends of the latter. The

lever 56 isconnected at one end to a station ary pivot 57, and at its other end is to the rod 47 as indicated at 58. n

Thedrain conduit 42 also communicates with the chamber 19. r

The operation of this embodiment of-my invention is as follows:

pivoted The pump provides a governing fluid pressure which is transmitted to the lower end of the relay casing 36 and biases the pilotvalve 48 upwardly against the force of the spring 54.

The governing fluid pressure 'is also transmitted to the chamber 21 of the pressure transformer 16, and a small quantity thereof flows through the passage 25 and the re,- stricted orifice 27 to the groove 29. 1

The upper end of-the cylindrical casing 36, the conduit 34, the passage 33, the groove 29, and the recess 59 provide anenclosed,

space in which thefluid flowing to the groove 29 is received. The restricted flow of fluid. into this space is controlled by adjustment of. the needle valve 26. and builds up the pressure thereinuntilthe pressure in the recess 59 acting on the valve 24, together with the governing fluid pressure onthepiston 23,

overcomes the force of the spring 32, when the valve 24 liftsand permits escape of fluid from the enclosed space to the chamber 19;

sure, the increased pressureacting'on the piston 23 raises the valve 24 slightly, permitting fluid to escape from the enclosed space until the pressure therein is reduced to offset the increased force exerted against the spring 32. Upon a decrease in governing fluid pressure, pressure on the piston 23 is reduced and the spring 32 moves the valve 24 to closed position until the pressure in the enclosed space builds up to again balance the spring 32 together with the pressure on the piston 23.

Upon an increase in speed of the prime moverthe pressure developed by the pump increases", increasing the pressureacting on the lower end of the pilot valve 48 and decreasing the pressure acting downwardly on the upperend. The sum of these pressure changes moves the pilot valve 48 upwardly until theincreased tension of the spring 54 equals the sum of the pressure changes. The port 43 is now in communication with the port 37, and fluid pressure is supplied to the upper end of; the cylinder 45, m0vi-ng the piston 46 downwardly to close the valves'in the steam chest 11. The port44 is placed in communication with the discharge port .41

and the fluid beneath the piston 46 is dis-. v

is decreased bya force-equal tothe sum of the pressure changes, The port 44, is placed in communication with the pressure supply port 37 andthe port 43 is placed in communication withthe-discharge port '39. The piston 46, therefore, moves upwardly to open the valves in the steam chest, and the leverv 56. moves upwardly until the piston portions 49 and. 51 again cover the ports 43 and 44. i

The speed setting of thegovernor maybe changed by turning the screw. 63 to vary the;

force-of the spring 32, and,therefore, the value of the fluid pressure in the enclosed vFrom the above description it will be apparent that I provide greater variations in the fluid-pressure acting on the pilot valve 48, whereby adequate movements of the operat- The pilot valve 48, moves downwardlyuntil the spring tensioning piston 46 may be obtained for a given j change in speed. .It will also be notedthat by increasing thegovern-ing action on the pilot valve 48, a greateropening of. the ports'43 I and .44, andhence a'morerapid operation of 1 the steam chest valves, 15 obtained. Upon an increase in governing fluid pres- Referring particularly to the pressure transformer, it "will be noted. that it isof It is also pointed out that the variations in fluid pressure above the pilot valve may be greater than the variations in the governing fluid pressure, and that the ratio thereof is determined by the inverse ratio of the areas in the pressure transformer on which the fluid pressures act. In the device shown on the drawing, for example, the area of the piston portion 23 is approximately twice the area of the-recess 59. Upon a given change in the governing fluid pressure acting upon the piston portion 23, therefore, there must be twice as great a variation in the fluid pressure in the recess 59 to offset the change in force opposing the spring 32. It is thus possible, by a choice of said areas, to obtain any magnitude of pressure variation on the pilot valve 48 for a given change in speed.

In Fig. 2, I show a modified form of pressure transformer 16, in which the governing fluid pressure is admitted through a conduit 15 and an orifice 61, and applied to a central recessed area 23 of a relief valve 24. A restricted flow of fluid passes from the conduit 15 through an orifice 27 to a conduit 34 and to an annular groove 29 in the casing 17',

where its escape is controlled by the relief valve 24'. Fluid escaping from the recessed portion 23 and from the groove 29, is discharged to a drain conduit 42.

The operation of the pressure transformer 16 is similar to that of the device shown in Fig. '1, a pressure varying inversely with the governing fluid pressure being transmitted through the conduit 34.

While I havecshown' 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 from said enclosed space and thereby controlling the pressure therein inversely to the first-mentioned fluid pressure, valve operating mechanism for controlling the admission valve and including a pressure responsive element and a spring biasing the element. said mechanism operating upon change in spring deflection to provide a valve movement proportional to the change in spring deflection, means for applying the first-mentioned fluid pressure to the pressure responsive element in valve closing direction,

and means for applying the fluid pressure in said enclosed space to said element in opposition to the first-mentioned fluid pressure so that the variations in the former fluid pressure assist the variations in the latter fluid pressure to provide increased spring deflection and consequent increased valve move ment.

In testimony whereof, I have hereunto subscribed my name this 7th day of June, 1928.

JAMES L. RAY.