US1621084A

US1621084A - Assighob to westinghouse

Info

Publication number: US1621084A
Authority: US
Publication date: 1927-03-15
Anticipated expiration: 1944-03-15

Description

March 15,1927. 84

J. P. RIGSBY AUTO STOP GOVERNOR Original Filed June 9, 1920 5 9 no .mflfj 7-; a

38 35 A, /g I! in as as 20 52 5 33 H l5 as I2 3? ATTORNEY Patented Mar. 15, 19217.

UNITED STATES PATENT OFFICE.

JOHN E. RIGSBY, OF ESSING'ION, PENNSYLVANIA, ASSIGHOB- TO WESTINGHOUSE ELECTRIC AND MANUFACTURING OOMEANY, CORPORATION OF PENNSYLVANIA.

AUTO STOP GOVERNOR.

Application filed June 9, 1920, Serial No. 387,520.

My invention relates to improvements in governing mechanism for steam turbines, and more particularly to that class of governing mechanism employed to automatically shut off the steam supply to the turbine when a predetermined overspeed is reached.

The object of my invention is the provision of manually controlled means whereby the governor mechanism may be made to operate at a speed below that for which it is adjusted, so that the condition of operation of the mechanism may be readily determined, and is especially intended for the purpose of testing the mechanism at any desired time.

I attain these objects by the mechanism illustrated in the accompanying drawing, in which Fig. 1 is a sectional view through the turbine shaft and housing showing the details of the governing mechanism; Fig. 2 is a sectional view showing the oil bath for the governing mechanism; and Fig. 3 is a view in elevation showing the governing mechanism applied to a steam turbine.

The overspeed governing mechanism, here after referred to as the auto stop governor, is mounted ina turbine-driven element or cap 10 having a thread 11 so that it may be screwed onto the end of the turbine shaft. The cap 10 is provided with an extension 12 having a diametral recess 13 with two shoulders 14-. and 15, the top of the recess being threaded at 16 to receive the retainer 17 whichis provided with a guide opening in which the weight 18 may slide. The retainer 17 holds the spring 19 in place and due to the threaded connection thereof to the recess, the tension of the spring 19 may be readily adjusted. The spring 19 also bears against piston 20 of weight 18 to maintain the piston in contact with shoulder 15. The collar 21 tightly fits in the recess 13 against the shoulder 14 and overhangs the latter in order to limitthe travel of the piston 20. The

' weight 18 is thereby prevented from passing beyond the point necessary to trip the lever 22 which acts through a suitable mechanism to shut off the steam supply to the turbine. The weight 18 has its center of gravity, indicated, for example, at 18, arranged at one side of the axis of rotation of the rotor shaft so that it is responsive to centrifugal force to move out and trip the element 22 in the usual way.

An axial passage 23 in the end of the Renewed December 28, 1923.

extension 12 of the cap 10 communicates through the passage 24 with the passage 25, the latter being parallel with the axis of the turbine driven element and giving a free passage from the clearance space 26 below the piston 20 to the outside. Preferably the weight 18 should fit loosely in the guide way of the retainer 17 and the piston 20 of the weight 18 should likewise be freely movable in the recess 13 in order to obviate all danger of sticking of the tripping weight. A slight leakage of fluid by the piston 20 is not objectionable but rather does it tend to equalize the pressures of oil above and below the piston 20 during normal-speed operation of the machine to which the autostop governor is attached.

In the housing 30 adjacent to the member 12 is mounted a mechanism whereby the end of the passage may be closed. This mechanism consists of a rod 31 provided at one end with a collar 32 and provided at the other end with a knob 33. The rod 31 is packed with reference to the casing by means of a stufling box consisting of packing 3d and compressing nut 35. A spring 36 is mounted on the rod 31 between the knob 33 and the compressing nut 35 in order to keep the mechanism in the disengaged position. On the end of rod 31 is mounted an annular member 37 which can be pressed against the end of the member 12 thus shutting off communication with the passage 25. The member37 is provided with a recess 38 to receive the collar 32 on the end of the rod 37. The end of the recess is threaded at 39 in order to receive the nut 40 which holds the collar 32 in place.

Referring now to Fig. 3, I show a steam turbine at having a well-known form of steam supply valve at 51, said steam supply valve being adapted to be automatically closed upon release of a tripping member 52 associated therewith. The tripping member 52 is pivoted at 53 and has a link 54 attached to its outer end. The link 54 is connected at its lower end to the lever 22 which is pivoted at 55. Upon the attainment of a predetermined speed by the turbine 50, the weight 18 protrudes outwardly in a manner already described, striking the lever 22 and causing a downward movement of the link 54. Upon a downward movement of the link 54, the tripping member 52 is disengaged and the valve 51 is closed.

The main governor of a steam turbine may not always function properly, and in such a case it is desirable to have an automatic stop governor to shut oil the steam supply in case the turbine acquires too high a speed. An auto-stop governor is generally designed to become effective at about 10% overspeed. If a turbine has been running at very nearly constant speedfor a long time and the main governor has been working properly, the auto-stop governor will not have been called upon to operate, and in such a case it is not uncommon for the auto-stop governor to get stuck which of course renders it practically useless. This might cause serious damage to the turbine on account of overspeeding.

In order to determine the working condition of the governor, the testing mechanism has been devised as herein described. This mechanism will function only when the end of the turbine shaft is immersed in oil. hen the annular member 37 is in the disengaged position as shown, oil will enter the passage 23 and will have a free passge through 24 and out at 25. in order to test the auto-stop governor. it is simg ily necessary to press the knob 33 until the annular member 37 engages with the member 12 thus preventing oil from escaping through the end of the passage 25. This will mean that oil entering at 23 will fill the passages 2a and 25. Due to the centrifugal force caused by the rotation of the turbine shaft, pressure will be built up in the column of oil in passage 24- and will be transmitted through the oil to the clearance space 26 below piston 20. This pressure acting a ainst the piston 20 together with the centrifugal force acting on weight will be sufficient to cause the weight 18 to move out and trip the lever 22 thereby shutting off the steam supply to the turbine. If after pressing knob 33 causing the annular member 37 toengage with member 12, the oil pressure built up does not cause the mechanism to operate, it will mean that the governing mechanism is not in the proper working condition and the cause of the trouble must be investigated.

Fig. 2 shows how the governing mecha nism may be immersed in oil or other suit able fluid to secure the operation referred to.

lVhile I have shown my invention 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 other changes and inodifications, without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are speciti cally set forth in the appended claims.

hat I claim is 1. An auto-stop governor comprising a rotary element, a trip clement carried by the rotary element and capable of moving to ripping position in response to centrifugal force, adjusting means cooperating with the trip element to secure trippin at a predetermined speed, and centrifugal fluidrc-developing means to render the trip clement operative at a speed below the predetermined speed and including means to control the operation of the pressuredeveloping means.

in auto-stop governor comprising a rotary element, a trip element carried there by and having a piston at one end, said trip element ec entrically weighted, adjustable tensioning means coopcrat'ng therewith to secure tri )ping at a predetermined '-controlled centrifugal fluidping m ans cooperaring with effective at .--;need.

-5. in auto-stop governor comprising a a speed below the predetermined turbine-driven element adapted to be immersed in oil, a trip element contiguous thereto, an eccentrically weighted element carried by the turbine-driven element move out to engage the trip element, said weighted element having means upon which a pressure tinid may act, said driven element having passages communicating with said means and terminating in inlet openings at the exterior of said element, one eccentrically disposed with reference to the other, and n anual means for closing said eccentric opening.

l. in auto-stop governor for a rotor shaft comprising a driven element adapted to be immersed in oil and provided with a transverse recess closed at one end and with a passageway in communication therewith near the closed end, said element also having and axial passages in communicaeccentric tion with each other and with the other par-sage, an eccentrically weighted trip element within said recess, a piston carried said elen ent, and an annular member adapted to close the eccentric passage.

in auto-st0p governor, the combinaon of a turbine-driven element adapted to immersed in oil, a weight element carried said turbine-driven element and having center of gravi y eccentric to the axis of otation, said weight element being capable f movement to tripping position upon the rttainrnent of prccetermined overspeed of "he turbine driven element, and said turbinelrivcn element leing provided with fluid "ranslat ng passages, one cccentrically disposed with relation to the other, to transtiuid from the exterior thereof to the w ight therein to cause tripping action at a speed below the predetermined overspeed, and a manually controlled member to close the eccentric passage.

6. In a turbine stop-governor an eccentrically displaceable element provided with a piston at one end, a turbine-driven element having a recess to receive the centrifugally displaceable element and adapted to run in oil, said turbine-driven element having axial and eccentric passages communicating between the exterior thereof and the recess below the piston of the trip element, and manually controlled means for closing the eccentric opening.

7. An auto stop governor comprising a rotary element, the rotary element adapted to be run in oil and provided with a recess, an eccentrically weighted element within the recess and responsive to centrifugal force, said rotary element having fluid translating passages communicating between the recess below the trip element and the exterior thereof. one of the passages being eccentrically disposed with relation to the other, a member to close the eccentric passage, and manual means for controlling the position of the member.

8. The combination with an auto-stop governing mechanism including an eccentrically-weighted tripping member and means to restrain movement thereof, of means to develop centrifugal force of fluid for application to the tripping member in opposition to said restraining means and means to control the fluid for the purpose of developing pressure.

9. The combination with an auto-stop governing mechanism adapted to operate at a predetermined speed, of means cooperative with said governing mechanism for develop ing centrifugal force of fluid, and means for at will applying said developed force of fluid. to secure operation of the auto-stop governing mechanism at speeds below said predetermined speed.

10. The combination with an autostop governor adapted to operate upon the attainment of a predetermined speed, of means for at will tripping said governor at speeds lower than said predetermined speed comprising means for developing a centrifugal force of fluid normally ineffective to trip said governor, and manually operable means for rendering said force of fluid effective to trip said governor.

11. The combination with an auto-stop governor adapted to operate upon the attainment of a predetermined speed, of means for at will tripping said governor at speeds lower than said predetermined speed comprising means tending to develop a centrifugal force of fluid operative to trip said governor and normally ineffective, and manually operable means to render effective the last-mentioned means in developing an operative pressure.

12. In an auto-stop governing mechanism the combination of an eccentrically-vveighted tripping member, a spring to restrain movement of the tripping member, means c0- operative with the governing mechanism for developing a centrifugal force of fluid, and means for at will applying said developed force of fluid in opposition to the force of said spring to secure operation of the said governing mechanism.

13. In an auto-stop governing mechanism, the combination of a rotary shaft of a machine with which the governing mechanism cooperates, an eccentrically-weighted tripping member carried by the shaft, a spring effective to resist movement of the tripping member outwardly in response to centrif ugal force, means for developing a centrifugal force of fluid normally ineffective to trip said governing mechanism, and manually operative means for rendering said force of fluid effective to trip said governor.

14-. In an auto-stop governing mechanism, the combination of a rotary shaft of a machine with which the governing mechanism cooperates, an eccentrically-weighted tripping member carried by the shaft, a spring effective to resist movement of the tripping member outwardly in response to centrifugal force, means associated with said shaft for developing a centrifugal force of fluid, and means for at will applying said developed force of fluid to said tripping member in opposition to the force of said spring.

15. In combination with the rotary shaft of a machine, an auto-stop governor for the machine comprising an eccentrically-weighted tripping member carried by the shaft and a spring effective to resist movement of the tripping member outwardly in response to centrifugal force, and means for at will tripping said governor comprising means associated with the shaft for developing a centrifugal force of fluid and manually operable means for applying said force of fluid to the tripping member in opposition to the force of the spring.

16. In combination, a prime mover, means controlling the flow of operating fluid thereto, an emergency governor operated by centrifugal force for effecting the actuation of raid means when the speed of the prime mover reaches a predetermined high value, and means operable while the prime mover is running for effecting an increase of the centrifugal force acting on the governor whereby it will actuate said means at a speed lower than that for which it is set.

In testimony whereof, I have hereunto subscribed my name this 4th day of June, 1920.

JOHN P. RIGSBY.