US1622100A

US1622100A - Governing mechanism for steam turbines

Info

Publication number: US1622100A
Application number: US387538A
Authority: US
Inventors: Warren B Flanders
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1920-06-09
Filing date: 1920-06-09
Publication date: 1927-03-22
Anticipated expiration: 1944-03-22

Description

W. B. FLANDERS GOVERING MECHANISM FOR4 STEAM TURBINES March 22, 1927. USZZJO() Original Filed` June 9; y1920 NVE TOR.

W.B.F om am:

Patented Mar. 22, 1927 nutren sraras Partnr ortica.

WARREN B. ELAN F PHILADELPHIA, PENNSYLVANIA, .SSIGNOB T0 WESTING- HOUSE ELECTRIC AND `ll/IANFA('J'IEUItING COMPANY, A CORPORATION 0F PENN- SYLVANIA.

GOVERNING MECHANISM FOR STEAM TUB/EINES.

Application filed .Tune 9, 1920,'Seria1 No. 387,538. Renewed January 9, 1926.

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

The object of my invent-ion is the provision ot manually controlled means where* by the governor mechanism may be made to operate at a speed below that for which it is adjusted. so that the condition oi 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

ltl

which Fig. 1 is a sectional view through av turbine shaft and housing showing details of a governing mechanism with my unprovement applied thereto; Fig. 2 is a detail' view showing parts oi' my improvement in a diderent operative position; and Fig. 3 is a sectional view showing the iiuid bath for my improved governor.

The overspeed governing mechanism, hereafter referred to as the autostop governor, is mounted on a turbine-driven shaft 10. The end ot the turbine-driven shaft 10 is 30 provided with an extension 11 having a diametral recess 12. The recess 12 has two

shoulders

13 and 14 and is threaded at`15 to receive the retainer 16. which is provided with a guide opening in which the weight r 17 may slide- The retainer 16 holds the spring 18 in place. and due to the threaded connect-ion thereof to the recess` the tension ot the spring 18 maybe readily adjusted. The spring 18 also bears against piston 19 of the weightor trip element 17 to maintain the piston in contactwith shoulder 14. The collar 2O tightly lits in the recess 12 lagainst the shoulder 13 and overhangs the latter in r order to limit the travel ot the piston 19. o The weight or trip element 17 is thereby prevented from passing beyond the point necessary to trip the lever 21 which acts througha suitable mechanism to shut off the steam supply to the turbine. The weight 17 has its center ot gravity, indicated. for example, at 17', arranged to one side of the axis of rotation of the sha-ft 10 so that it is responsive to centrifugal torce to move out and trip the element 21. A

A clearance space 22 is provided below the piston 19 which communicates with the eX- terior of the turbine'driven shaft through the eccentric passage 23. A similar eccentric passage 24 is provided on the opposite side of the shaft l() which communicates with the passage 23 through the passage 25. rlhe axial passage 26 communicates between the exterior of the shaft 10 and the passage 25 and is chamtered at its entrance as shown. In the casing 30, adjacent to the end of the turbine shaft 10, is mounted a mechanism' whereby the ends of the

passages

23 and 24 may be closed. This mechanism consists of a rod 31 provided at one end with a threaded extension of diminished diameter 32 and at the other end with a flange 33. The rod 31 is supported with reference to the casing by means of the two bushings 34 and 35. In the space 36 between bushings 34 and 35 and on rod 31 is mounted a spring 37 rest ing against bushing 34 and pressing againstV collar 38 of rod 31. Mounted on the end of rod 31 is an annular member 39 flexibly connected to the flange 33 by means of the diaphragm 40. The diaphragm 40 is secured to the annular member 39 by a series of screws 41 and to the flange 33 by a washer 42 and rivet or other means 43. The annular member 39 is provided with one or l more entrance passages 44 which permit oil to enter the space between the inside of the annular member 39'and the diaphragm 40.

The spring 37 pressing against collar 38 ot rod 31 serves to keep the annular member 39 inl contact with the end of the shatt 1() thereby closing'the ends ot the passages v23 and 24. In this position the annular member 39 is prevented from rotating with -the shaft 10 by means of the pin 45 mounted in rod 31 and engaging two slots 46 cut in opposite sides ot' the bushing 34. On the extension 32 of rod 31 may be mounted a until pin -15 clears thc face ot' bushing 3-l and then turn rod 3l until pin 45 can rest against the solid face oi bushing 534e.

The main governor ot a steam turbine. may not al ays function properlyT and in such a case it is desirable to provide n automatic stop governor to shut oil the steam supply to the turbine when too hi gli a spec-l is reached` An auto-stop governor Yfrenerally designed to become effective at about 10% overspeed. It the turbine has been running at constant speed for a long time and the auto-stop governor has not been called upon to operate, it is not uncommon :tor the auto-stop governor to eet 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' conditions of the auto-stop governor. the testing' mechanism has been devised as herein' dcscribed. rllhis mechanism will function only when the end ot the turbine shaft is run in oil. `When the annular member is in the disengaged posit-ion, oil Will enter par.- sage and Will have a tree path through passage 25 and out through passages 28 and Q4. In order to test the auto-stop lgovernor it is simply necessary to turn handle l? until pin 45 registers with slots 4G. rllhe spring 3l' Will then `torce the annular member Si) against the end of the turbine shaft l0 thereby closing passages 23 and Q4 @il entering through passage 26 Will then till passages 23,724. 25 and the clearance space belenv piston 19. Due to the centrifugal force caused b v the rotation of the turbine shaft` pressure will be built up in the column of oil in passage 25 which vvill be transmitted through the oil to the clearance space 22. his pressure acting' against piston 19 together with the centrifugal torce acting);

on Weight 17 will be sutiicient to cause the Weight 17 to move out and trip the element 2l thereby7 shutting' ott the steam supplv to the turbine. If the oil pressure does not cause the mechanism to operate it Will mean that the governing` mechanism is not in the proper Working' condition. and the cause ot the trouble must be investigated.

Ililhile I have shoivn my invent-ion in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible ot various vother changes and modilications, Without departing; trom the spirit thereof. and I desire. therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or are speciiically set forth in the appended claims.

What I claim is l. In an auto-stop governing; mechanisrm the combination of an eccentrically Weighted tripping' member, means :tor resisting' movement of the tripping member in response to centrifugal force, means for developing;` ccntritug'al force of Huid for application to the tripping member in opposition to said resisting means, controlling means lor rendering the centrifugal fluid n'cssure developing means eii'ective or ineffective` and means ttor maintaining the latter means .nornnilhv in inetfect-ive `position.

2. rl`hc combination with an auto-stop lgovernor having an eccentrically Weighted tripping' meniber and a spring' tor resisting movement ot the latter in rcsponfe lo centrifugal torce, of means i'or developing ceutrifugal torce ot' tluid pressure tor application to the tripping' member in opposition to the spring, controlling` means ttor rendering the centrifugal Huid pressure developing means eltective or ineiective, and a spring for maintaining the latter means in ineiiective position.

3, An auto-stop governor'comprising a rotaryY element having; a diametral recess and axial and eccentric nassageu'avs in communication therewith, an eccentrically Weighted trip element Within said recess and having` a piston 'connected thereto, adjustable tensioning' means to secure operation ol Vthe trip element at a predetermined speed,`

an annular member adapted to close the eccentric passage, and means cooperating with the annular member to maintain it either in operative or inoperative position 4. An auto-stop governor comprising a rotary element adapted to be immersed in a liquid, an eccentricalli Weighted trip elenent carried therein7 and capable ot movingv to tripping' position on attaining` a predetermined speed, va piston secured to said trip element7 said rotary element having' axial and eccentric passages communicating with the space beneath the piston, a ring element adapted to close the Veccentric passages and havingl ports to ati'ord communication or" the axial passage With the exterior When the ring is in close-d position, a flexible diaphragm connected to the ringiand manually controlled means connected to the diaphragm for moving' the ring into and out ot position.

5. In a governor mechanism the combination of a rotary element having' a recess With apiston chamber at the lower end, an eccentrically Weighted element Within the recess and having` a piston fitting Within the piston chamber, spring` means associated With said element to secure movement thereot to tripping' position upon attainment ot a predetermined speed by the rotar)7 element, said rotar)7 element having` axial and eccentric passap'es in comnmunication With the undersurtace ot' the pi `ton and means to close the eccentric passages including a member having' ports to alilord communication between the axial passage and tue exterior of the rotar)T element7 a iiexible diaphragm secured to the member, a spring pressed means to exert pressure` against the diaphragm to maintain the member in contact with. the rotary element to clef-fe the eccentric passages.

(i. An autostop governor comprising a rotary clement having` a diametral recess with a` piston chamber and clearance space at the bottom thereof, an eccentricallyr weighted trip element within the recess and having a piston {ittingg vithin -the piston chamber, ,adjusting means cooperating with the trip element to secure trippinc' at a predetermined speed, said rotary element having axial and eccentric passages communicating with the yclearance space, a ring adapted to close the eccentric passages and having one or more ports to afford communication between the axial passage and the exterior' of the ring, manual means to withdraw the ring from closing position, and spring means to maintain the ring in the closing position.

7. An auto-stop governor comprising` a rotary element. adapted to be immersed in a liquid having' a diametral recess with a piston chamber and clearance space at the bottom thereof, an eccentrically weighted trip element within the recess and having a piston fitting within the piston chamber, adjusting means coopera-ting` with the trip element to secure tripping` ata predetermined speed, said rotary element having axial and eccentric passages in communication with the clearance space below the piston, means to close the eccentric passages, pressure means to maintain the closure means in closed position, and means to move and maintain the closure means in inoperative position.

8. An auto-stop governor comprising a rotary element adapted to be immersed in a fluid and having a diametral recess withV a piston chamber and clearance space at the bottom thereof, and eccentrically weighted trip element within the recess and having a piston portion fitting within the piston chamber, adjusting means cooperating with the trip element to secure tripping at a predetermined speed, said rotary element having axial and eccentric passages in communication with the clearance space beneatn the piston portion, a ring to close the eccentric passages and having passages to afford communication between the axial passage and the exterior thereof, a iexible diaphragm secured to the ring, and spring-pressed contro; means connected to the diaphragm.

9. An auto-stop governor coimorisingl a rotary element having` a diametral recess with a piston chamber and clearance space at the bottom thereof and adapted to be immersed in a liquid` an eccentrically weighted trip element within the recess and havingl a piston portion [ittina` within the piston chamber, adjusting means cooperat ing with the trip element to secure tripping at a predetermined speed, said'rotary element having` axial and eccentric passa-ges in communication with the clearance space be neath the piston portion, closure means for the eccentric passages, control means flexibly` connected with the closure means`v spring means to maintain the closure mea-ns in active position, and means to position the control means to maintain the closure means in inoperative position.

l0. An auto-stop governor comprising a rotary element having a recess with a piston chamber and clearance space, an eccentrically Weighted trip element within the recess and having a piston portion fittingr within the piston chamber, said rotary element having' eccentric and axial passages within the end thereof and in communication with the clearance space beneath the piston portion, closure means for the eccentric passages having' ports to afford communication between the axial passage and the exterior thereof, control means for the closure means flexibly connected thereto, supporting means for the control means, spring means carried by the supporting means and cooperating with the control means to maintain the closure means in active position. pin-andslot means cooperating with the control means and the supporting means to maintain the closure means in an ineffective position.

11. An auto-stop governor comprising a rotary element having a recess with a piston chamber and clearance space at the bottom thereof and adapted to be immersed in a liquid, an eccentrically weighted trip ele ment within the recess and having a piston portion fitted within the piston chamber, adjustin means cooperating with the trip element to secure tripping at a predetermined speed, said rotary element having eccentric and axial passages in communication with the clearance space beneath the piston portion, a closure ring for the eccentric passage and having passages to afford communica- Y tion between the axial passage and the exterior thereof, a flexible diaphragm connected to the ring.y a spring control means connected to the diaphragm to maintain the closure ring in effective position, and means cooperating with the last named means to withdraw the closure means and maintain it in ineffective position.

12. An auto-stop governor comprising a rotary element having a recess with a piston chamber and clearance space at the bottomy thereof and adapted to be immersed in a liquid,A a casing element for the rotary element, an eccentrically weighted trip element within the recess and having a piston portion fitting the piston chamber, adjusting means cooperating with the trip element to secure tripping at a predetermined speed, axial and eccentric passages in communication with one end of the rota-ry element and with the clearance space beneath the piston portion, a closure ring tor the eccentric pasa: ges and haring passages adapted to afford communication between the axial passage and the exterior thereof, a flexible diaphragm connected to the ring, a rod Connected to the diaphragm and passing through the easing' element, means acting on the rod to maintain the ringjr in closingr position, and means associated with the rod whereby it may be withdrawn and retained in such a position as to maintain the closure ring' ineffective.

13. in auto-stop governor comprising` a rotary element having a recess with a piston chamber and clearance space at the bottom thereot and adapted to be immersed in a liquid, a easing,- element therefor, an eccentrically weighted trip element within the recess andY havinp` a piston portion iitting,` within the piston chamber, adjustingmeans cooperating;` with the trip element to secure trippingl at a predetermined speed, said rotary element having` axial and eccentric passages affording eonnnunication between one end thereof and the clearance spare beneath the piston portion, a closure ring for the eccentric passages and having` passages adapted to afford communication between the axial passages and the exterior thereof, a control rod flexibly connected to the closure ring, and passing;` through the easingl element to be operative from the outside, an abutment on the rod, a spring` between the abutment and a portion of said easing element to exert pressure on the rod to cause the closure rintgto be maintained in closing position, means `for retraetingv the rod and means cooperating` with the rod and the springl to maintain the rod in retracted position when the latter is withdrawn and turned.

la. The combination with an auto-stop governor having an eeeentrically weighed tripping; member and means for resisting movement of the tritugal force, of means adapted to develop centrifugal :torce of fluid pressure and adapted to be normally ineffective, and biased means adapted to be manually operated to render said means effective.

ln testimony whereof, have hereunto subscribed my naine this 4th day ot June, 1920,

VRREN B. FLANDERS.

latter in response to een-y