US2385201A - Governor apparatus - Google Patents

Description

Sept 18, .1945. M. GOTTLIEB GOVERNOR APPARATUS Filed May 26, 1943 I NVENTOR Amy/00s GOTTA/EB BY 01/, (f5 M ATTORNEY Patented Sept. 18, 1945 UNITED STATES PATENT OFFICE GOVERNOR APPARATUS Manious Gottlieb, Philadelphia, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 26, 1943, Serial No. 488,590

4 Claims.

In the application of my prior Patent No. 2,239,602 of April 22, 1941, assigned to the West-- inghouse Electric 8; Manufacturing Company, to situations where sudden changes in speed are required, as with the governor applied to the propulsion turbine of an electric drive ship installation and in connection with which it is desired to provide for crash stop operation, the compensating pressure should be relieved to obtain the desired quick response of the governor valve.

In the electric drive installation, delay in opening the governor valve is encountered for the reason that, when the control lever is moved rapidly in the slow speed direction, pressure is maintained or builds up in the compensating chamber and opposes quick opening of the turbine admission valve. In accordance with the present invention, the governor compensator is equipped with a relief feature which becomes effective immediately upon movement of the control lever in the slow speed direction rap dly, in which event the rapid decrease in loading of the governor load spring is accompanied-by an unbalanced centrifugal force or effect used to open the relief feature and therefore to prevent the maintenance or building up of compensating pressure hindering rapid opening of the governor-operated turbine admission valve. The modification of the governor to satisfy these rapid speed change conditions does not impair its effectiveness in responding in a speed-compensated manner to more gradual speed changes.

Therefore, it is the object of the invention to provide a governor of the type referred to wherein provision is made for relief of the compensating pressure in the event of rapid adjustment to the slow speed position.

This and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a diagrammatic view showing the invention applied to an electric drive installation;

Fig. 2 is a sectional view showing the governor mechanism more in detail; and

Fig. 3 is an enlarged detail sectional view showing the compensator relief.

The application of the invention to an electric drive installation will be clear from a consideration of Fig. 1 and the application of Schwendner, Serial No. 470,555, filed December 30, 1942, assigned to the Westinghouse Electric & Manufacturing Company. The admission of elastic fiuid,

hereinafter referred toas steam, to the turbine II is controlled by a governor, at H. The turbine drives a generator l2 synchronously connected to the propulsion motor l3, Operation of the turbine and the electfic drive are under control of control mechanism, at l4, including a speed lever ii.

The lever It operates, through a suitable servomotor (not shown), to adjust the speed changer of the governor.

The governor, at H, is of the fiyweight transformer-type and it includes a spindle I 8 operatively connected to rotate with the turbine. The spindle carries a diametrically-extending leaf or strap spring is to which is attached flyweights 20. Between the flyweights and in axial alignment with the spindle,'the spring is formed with a thrust abutment portion 2|, preferably attached to the supporting disc 22 for one end of the load spring 23. The disc is formed with a central cup 24 within which is disposed the thrust ball 2!, engaging the lower end of the valve or thrust rod, at 28. Preferably the central portions of the leaf spring is and of the disc 22 are attached by a screw 21 whose threaded shank 28 engages the ball and whose head 29 is adapted to engage the abutment 30 to confine movement of the governor within a desirably small range.

The upper end of the load spring 23 is engaged by an abutment ring 32. A roller thrust bearing II is interposed between the abutment ring and the speed changer ring 34, which is adjustable axially of the barrel 35 of the stationary body structure to change the loading of the load spring. As shown, the ring 34 is threaded to the barrel and is turned by means of suitable gearing, at 36, operatively connected to the lever IS.

The body structure is formed to provide 9. cylindrical chamber 31 with which cooperates a disc 38 to provide an annular supply orifice 39 whose upstream side is open to a supply passage 40 connected to any suitable pressure source. The lower end of the cylindrical chamber 31 is open to the valve chamber 4| formed to provide a valve seat 42 bounding the lower end of the cylindrical chamber. A cup valve 43 has a, rim 44 cooperating with the seat to define an annular escape oriflce 45. Thus, it will be seen that the supply oriilce 38 and the escape orifice 45 define a pressure space 46 in which the pressure is a function of the rate of escape through the orifice 45 controlled by very small adjusting movements of the cup valve toward and from its seat.

The cup valve 43 is attached to the stem structure, at 26, to form a valve body and the stem structure includes an upper cylindrical portion 48 and a lower cylindrical portion 49, the portion 48 being of larger diameter than the portion 49 and such portions fitting cylindrical bores 50 and respectively, formed in the barrel 35. The upper cylindrical portion is tubular. The upper cyiindrical portion 48 provides an annular piston area or face 52 exposed to the compensator chamber 53 formed in the body.

A transformed pressure supply passage 54, forming a part of the transformed fluid pressure space 46, is connected to a pressure-responsive device 55 of the turbine valve operating servomotor 58. V

The transformed fluid pressure space 46 is connected to the compensator chamber 53 by passages including the passage 51, the chamber 58 and the passage 58.

'The passage 51 has a needle valve 60 and the chamber 58 is bounded in part by a spring-expanded bellows GI whose interior communicates with external space by means of the oriflce 82. There is thus provided an accumulator whose action is timed by means of the orifice'provided by the needle valve 60 so as to render the chamber 53 effective in a compensatory manner, as more fully described in the patent aforesaid.

As pointed out in said patent, the compensator compensates for the speed change due to load change. A change in load results in operation of the governor in the normal way,- that is, a deviation in'speed is used to modify the motive fluid admission to suit the load; however, this deviation or change in speed is only temporary for the reason that the compensator uses the speed change or deviation to effect further modification of motive fluid admission to reduce the speed change. With full speed correction, the governor is isochronous.

Assuming the load to decrease, the first effect is for increase in centrifugal force of the flyweights 20, causing slight movement of the cup valve 43 to restrict the escape orifice 45 with in-. crease in transformed fluid pressure and reduced admission of steam to the turbine until the change in force of the fluid acting on the cup valve balances the change in centrifugal force. However, just as soon as the transformed fluid pressure starts to increase, the pressure in the compensator chamber also begins to increase but so at a much slower rate depending upon the needle valve adjustment and characteristics of the accumulator. As the compensator pressure increases, the force of such pressure acts upward- 1y on the piston area 52 to move the cup valve further in a closing direction to secure further increase in transformed fluid pressure and further reduction in motive fluid admission to reduce the turbine speed to bring about reduction in speed change due to load change. Thus, the change in transformed fluid pressure due to load change is used to effect further change in transformed pressure to reduce the speed change due to load change.

If there is an increase in load, the reverse operation takes place, the temporary reduction in transformed fluid pressure pursuant to reduction in speed being followed by reduction in pressure at a very much slower rate in the compensator chamber, thereby allowing increase in escape area of the escape orifice to further reduce the transformed fluid pressure with proportionate increase in motive fluid admission in order to reduce the speed change due to load change.

Where the speed change is relatively small, the

piston area 52 may be so chosen that the force of compensator pressure acting thereon may balance the force of transformed fluid pressure acting on the cup valve, in which case compensation provides for isochronous operation. On the other hand, in variable speed situations, the speed change from no load to full. load is increased as the operating speed is reduced; and, as pointed out in the aforesaid patent, the piston area 52 is made sufficiently larger than the cup valve pressure area to compensate for the scale effect of the load spring 23 so that the speed changer ring 34 may be operated over a very wide speed range with minimum speed change due to load change at each speed setting.

While the aforesaid governor is well suited for control of a marine propulsion turbine operating over a wide speed range, nevertheless the required response does not have the desired rapidity under extraordinary operating conditions, such as a crash stop. If the speed control lever I! is moved quickly to reduce the speed, this movement being accompanied by upward movement of the speed changer ring 34, and if the valve stem structure, at 28, and the valve body were a unitary construction, the latter would respond quickly under the influence of centrifugal force to restrict the escape orlflce 45 to increase the transformed fluid pressure, this increase in transformed fluid pressure being accompanied by increase in compensating pressure, Now, if it is desired to secure quick opening of the governor-controlled motive fluid admission valve for the turbine, the pressure in the compensator chamber 53 delays this operation excessively.

Therefore, means is provided to prevent maintenance or building up of compensating pressure when low speed adjustment is quickly made.

Instead of the valve or thrust stem structure, at 26, being unitary with the valve body, it is constructed so as to have telescopic shortening movement against the force of a spring. The stem structure includes the upper and lower cylindrical portions 48 and 49 which are made hollow to provide, respectively, the chamber St and the cylindrical guide 65, the lower end of the upper cylindrical portion being formed to provide a bottom wall 86 for the chamber 6 3. A thrust rod or stem 51 fits the guide 65, to provide for telescoping of the stem structure. The lower end of the rod 61 normally abuts the ball 25 and the upper end thereof is attached to a disc 68 in the chamber 64 and which is adapted to abut the bottom wall 68 to limit the maximum or normal operating length of the stem structure. The maximum or normal operating length of the stem structure is maintained by a spring 69 in the chamber 64 and abutting the disc 68; however, in the event of upward force of the rod exceeding the opposing force of the spring, the latter yields to allow for shortening of the stem structure.

The disc 88 normally covers ports 70 formed in the bottom wall 66 and open to a compensator chamber 53. The upper end of the chamber 64 is in open communication, by means of passages ll formed in the valve body 43, with the exhaust space 4|.

If movement of the stem 61 occurs with sufflcient rapidity, as would be the case when the control lever I5 is moved quickly to slow speed position for a crash stop, then such rod moves relatively to the hollow portions 48 and 69 of the stem structure and opens the by-pass port or ports 10, thereby relieving or preventing presassasoi sure accumulation in the chamber 53, with the result that the latter is conditioned to permit rapid downward movement of the cup valve, 43 to reduce the transformed pressure and-open the admission valve, whereby excessive delay in opening the governor valve and due to pressure in the chamber 53 is avoided.

As already pointed out, I prefer to use a governor capable of adjustment over a wide speed range with good regulation at each speed setting from no load to full load; and, to provide for a small percentage of regulation over a wide speed range, the piston area 52 is made enough larger than the pressure area provided by the cup valve to compensate for change in scale of the load spring for the full range of adjustment thereof. To keep the valve aggregate in abutting relation with the thrust ball 25, any suitable biasing means may be used for this purpose. As shown, pressure acting on the upper face of the orifice-forming disc 38 serves this purpose.

The governor illustrated is more generally claimed in my aforesaid Patent No. 2,269,602 and such governor with the telescopic valve stem feature is disclosed and claimed in my prior Patent No. 2,332,910, granted October 26, 1943. The present invention involves the by-pass or relief valve feature constituted. for example, by the port I0 and'the valve disc 68, as above described, applied to the governing arrangement of the first patent and to the stem arrangement of the second patent if the latter is used.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various'changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically setforth in the appended claims.

What is claimed is: I

1. In governing apparatus, means providing a transformed liquid pressure space having an escape port, a valve body including a cup valve cooperating with the first means to provide an escape orifice for the port, means providing a compensating chamber, said valve body having a pressure area exposed to the interior of the compensating chamber and which is disposed in opposed relation to the pressure area provided by the cup valve, a passage connecting the transformed pressure space and said compensator chamber, means providing an orifice in said passage, an accumulator communicating with the passage between the orifice and the compensator chamber, a thrust rod, a spring acting on'the valve body and thrust rod to maintain a predetermined distended relation thereof, valve means opened in response to movement of the thrust rod relative to the body to provide a by-pass for the compensating chamber, a thrust member in thrust-transmitting engagement with the thrust rod, means for developing and applying thrusts to the thrust member including flyweights subject to centrifugal force and a load spring, and a movable member for-varying the loading or the load spring.

2. In governing apparatus, a body structure providing a transformed liquid pressure space having an escape port for discharge of liquid to an exhaust space; a valve aggregate comprising a cup valve and a stem construction attached thereto; said cup valve being in covering relation with respect to the escape port and coopcrating with the body structure to provide an escape orifice for said transformed liquid pressure space; said stem construction including a tubular element and a thrust rodtelescopically arranged with respect thereto; said tubular element comprising upper and lower cylindrical portions joined by a radial wall portion; a head attached to the upper end of the thrust rod and arranged in overlapping relation with respect to said radial wall portion; a spring arranged within the upper cylindrical portion and exerting force on the head to maintain the latter in abutting relation with respect to the radial wall portion; said body structure providing cylindrical guides for said upper and lower cylindrical portions of the tubular element and a compensating chamber to which said radial wall portion is exposed; means providing an accumulator; passages connecting the transformed liquid pressure space and the compensating chamber with the accumulator; means providing a restricted orifice in the passage between the transformed liquid pressure space and the accumulator; said upper cylindrical portion of the tubular element having a passage affording communication of its interior with the exhaust space and said radial wall portion having one or more ports operative to afford communication between such interior and the compensating chamber and normally closed by said head; a thrust-transmitting member in abutting relation with respect to the lower end of said thrust rod; flyweights operative under the influence of centrifugal force to exert thrust on the thrust-transmitting member; said thrust rod and its head movin relative to the tubular member with compression of the spring within said uppercylindrical portion to open the port or ports'in said radial wall portion to place the compensating chamber incommunication with the exhaust space when the thrust due to centrifugal force increases at a rate sufilcient to compress such spring; a load spring exerting .force on the thrust-transmitting member in opposed relation to the centrifugal force exerted thereon by the flyweights; and means for varying the loading of the load spring.

3. In governing apparatus, a body structure providing a transformed liquid pressure space having an escape port for discharge of liquid to an exhaust space; an orifice for supplying fluid from a suitable source to the transformed liquid pressure space; a valve aggregate comprising a cup valve and a stem construction attached thereto; said cup valve being in covering relation with respect to the escape port and cooperating with the body structure to provide an escape orifice; said stem construction including a tubular element and a thrust rod telescopically arranged with respct thereto; said tubular element comprising upper and lower cylindrical portions joined by a radial wall portion; a head attached to the upper end of the thrust rod and arranged in overlapping relation with respect to said radial wall portion; a spring disposed within the upper cylindrical portion and acting on the head to keep the latter in contact relation with respect to the radial wall portion; said body structure providing cylindrical guides for the upper and lower cylindrical portions of the tubular element and a compensating chamber to which said radial wall portion is exposed; means providing an accumulator; passages connecting the transformed liquid pressure space and the compensating chamber with the accumulator; means providin a restricted orifice in the passage between the transformed liquid pressure space and the accumulator; said upper cylindrical portion 01' the tubular element having a passage affording communication of its interior with the exhaust space and said radial wall portion having one or more ports operative to aflord communication between such interior and the compensating chamber and normally closed by said head; a thrust-transmitting member cooperating with the lower end of said rod; fiyweights operative under the influence of centrifugal force to exert thrust on said thrust-transmitting member; said thrust rod and its head moving relative to the tubular member with compression of the spring within said upper cylindrical portion to open the port or ports in said radial wall portion to place the compensating chamber in communication with the exhaust space when the thrust due to centrifugal force increases at a rate sufllcient to compress such spring: a load spring exerting force on the trust-transmitting member in opposition to that exerted thereon by the iiyweights; means for varying the loading of the load spring; said radial wall portion having such diameter that the piston area provided thereby and exposed to the compensating chamber is sufllciently larger than the pressure area f the cup valve to compensate for the varying scale effect or the load spring; and means for exerting biasing force

Images