US822256A - Governing mechanism for turbines. - Google Patents

Description

IMP 822,256. PATENTED JUNE 5, 1906.

W. L. R. EMMET. I

GOVERNING MECHANISM FOR TURBINES.

, APPLICATION FILED APH.1904.

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'PATBNTED JUNE 5, 1906.

No. 822,256. I

W. L. R. EMMET. GOVERNING MEGHANISM'POR TURBINES.

APPLICATION FILED APR. 5, 1904.

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UNITED STATES PATENT OFFICE.-

WILLIAM L. R. EMMET, OF SCHENEOTADY. NEW YORK, ASSIGNOR TO.

GENERAL ELECTRIC OOMPANY,A CORPORATION OF NEW YORK.

GOVERN-ING ME CHANISM FOR TURBINES.

Specifi oation of Letters Patent.

. Patented June 5, 1906.

Application filed April 5, 1904. Serial Nb. 201.747.

- isms for Elastic-Fluid Turbines, of which the following is a specification.

Certain types of turbines as commonly constructed are provided with separatelyf actuated nozzle-valves, each valve-being capable of opening and closing independently of every other valve. Each nozzle-valve is operated by a fluid-actuated motor, and in orderto control the. motors, and therefore the valves, arelay orauxiliary valve is providedfor each motor, the relay-valves in turn being controlled by a device responsive to load changes-such, for example, as a fly-ball governor. As constructed the nozzle-val es, motors, and'relay-valves are included in the same structure. Practice has demonstrated that owing to the frequency with which the nozzle-valves are opened and closed b the motors the force exerted by each motor as a tendency to break the stem or connection be-.

tween it and the valve.

In order to start the motors from a position of restand in a direction to close the valve, springs are employed, which are located between the head of the motor Iston and the cylinder-head- I have foun that these'springs are liable to lose their temper when subjected to superheated steam or other fluid and also that with the constructions heretofore employed they are too short unless the mechanismas a whole is made unduly large. Some difiiculty has also been experienced in operating the relay-valves.

The present invention has for its object to improve the governing mechanism of elasticl'luid turbines by obviating the objections set forth above. The means by which these objections are obviated will be set forth more fully hereinafter, to ether-withcertainother features of improve construction.

In the accompanying drawings ,which illustrate one embodiment of my invention, Figure 1. is a view in side elevatlonof an elasticfluid turbine of the multistage jet type.' Fig. 2 is an enlarged sectional view through the valve-chest and a nozzle-valve. Fig. 3 is an enlarged sectional detail view of a relay-valve for controlling the motor which actuates the Mounted upon the casin nozzle-valve; and Fig. 4 is adetail view of the cam-cylinders situated on opposite sides of the turbine, with means for transmitting motion from one to the other.

1 represents the base of the machine, which is connected to a condenser or atmosphere by the, conduit 2. Mounted above the base is the casing 3, which includes one or more bucket-wheels, as the case may be. Usually a number of valves will be provided. is a stool 4, that su ports the dynamo e ectrlc machine or ot er load device 5.

The upper end of the dynamo is provided with a cover, which supports the dome 6, the

latter surrounding the speed-responsive device 7 and carrying the lever 8 for transmitting motion from said device to the mechanism for controlling the relay-valves. speed-responsive deviceis attached to the upper end of the turbine-shaft, which also carries the revolving member of the dynamo. Mounted on top of the turbine-casing are one or more steam-chests 9, containing a plurality of individual nozzle-valves which have an open and a closed position, but no intermediate. evenly about the wheel, I prefer to arrange the nozzle and other controlling valves 1n groups. In the present illus atio two groups of nozzles are shown, eac comprising a plurality of sections, twelve being shown in the present illustration. Steam, or other elast;c fluid is delivered to the chest b. a condu.t 10, which surrounds or partia ly surrounds the stool. The conduit is in turn spplplied from the pipe 11, leading from the Referring to Fig; 2, the construction and arrangement of the nozzle-valves and their actuating mechanism will be described. Since all of the parts are duplicates, a. description of one of them will be sufficient. '9 represents the steam or valve chest, which is pro-' vided with front and rear curved walls'tomake it conform tothe shape of the turbinecasing and stool. In Fig. 2 the left-hand wall of the chest is the front wall in Fi 1. The interior of the chestis cored out to form a chamber 12, which is or may be common to all of the valves. Extending downwardly from the chamber are as. many nozzle-passages 13 as there are nozzle-sections. These passages are formed in the projection 14, that In order to distribute the strain The:

log

constitutes an extension of the bottom wall l pressure steam; but as the lever 47 decreases of the chest. To the lower end of the projection is bolted or otherwise attached a sectional-nozzle 15, comprising a plurality of chrvlyassociated nozzle-sections, each of Whit l is provided with a well-rounded bowl i6 and a throat and zlischarge-ori'lice of suitable shape. These sections should have the same angle oi" delivery and the same ratio of expansion where expansion is necessary.

Each passage 13 may supply one or more seei.i-; ns of the nozzle, desired, and each noz- .zcle -passagc may and preferably does cover re thanonebucket-space. Tl'ieupperwall oi the chestis bored out to form a cylinder or the motor-piston 18, which opens and closes the nozzle-valve 19. The valve pro vided. with a removable seat 20, that carried by the lowcr part of the valve-chest. 21 represents the head of the cylinder, which is provided. with an elongated projection :22, that enters the barrel 23, that connects he n'iotorpist m it; and the valve 19. The projection is provided with. a vcrti'cally-exteml-- ing passage 24. which conveys high-pressure fluid to the inside ol the barrel. It is'also provided with one or more transverse passages 25, which communicate with the vertical passage and .dischar e steam into the cylinder l7 behind the piston. 'lhc piston is provided with a suitable packing-such, for

exalnr as a plurality oi groovcs-and on the inside makes a closc lit with the cylindri al surl'n c on the up; #2 end of the projection 2- 1 Surroundihg the proicctirm and lo cated bctwccn it and l he barrel is a compres- 'sion-spring o, which tends at all times to closc the valve against the pressure exerted upon the piston b thc'lluid in tlu.* chambcr l2. liy placing the spring inside ol' the barrcl it is in a incasurc protwrted l'rom the hot steam in the chest and by rcasonol' its having considerable length it is not so liable to injury as a short spring. lt is more reliable in operation, since it easier to make a long sprii'ig with the desired scale than it is a short one. Situated in 'the cylinder and above the piston is a spring-platcZT, that serves to reduce the shock caused by the o wning oi thcvalvc. As the piston lllUVOs upwardly and passes the ends oi the transverse passage a certain amount of motive fluid is trapped in the cylinder, which. lluid acts as a cushion lor the o eningvalvc.

in order to control tlurorwning and closing ol' the nozzlcw alvcs corresponding relayvalves 28 are provided, each val-'vc being straight in a hmgitudinal direction instead o'l' curved, like the steam-chest. 'llos is done in mounted in a suitable valve-chest 25), that is i order that a single can] will be saillicicnt to opcralc all of the valws and also lhat'thc rela. ,'-valves may be 01' corresponding lcngt h. When the rclay-valvc r. on its lower seal, a relatively small arm is exposed to the luglk the pressure on the spring 44 by a certain amount the steam-pressure thereon will be sul'licient to start the valve, and since the exposed area suddenly increases the valve will open. with a sudden movement or jump, and thus prevent cutting of the valve or its seat. The relay-valve chest is provided with as many cylindrical openings as there are relayvalves, and each opening is provided with a cover 30, which has a projection on its under side, the said projection being provided with a valve-seat 31, Fig. Extending transversely and just above the valve-seat is a passage 32, that communicates with the exhaust 33. In addition. to the transverse passage is a circumferential groove that connects with the ends of the passage and opens into which communicates with the source of high pressure such, for example, as the pipe 37, the latter being connected to the chamber 12. in addition to the passage 36 two or more vertically-extending passages 38 are provided, which when the relay-valve 28 is raised from its seat admit high-pressure fluid into the passage 39, tl'ielatter being connected by the pipe 40 withthepassage 24' and the upper sid of the motor-piston. In the pipe 40 and in a position where it is readily accessible is a cut-ofi valve41, byuneans oi which any given motor and its nozzl'ewalve can be cut out of service.

The relay-valve chest mounted on two or more posts 42, which support it at a point some distance from the nozzle-valve chest. By.this arrangementthe parts are rendered easily accessible and the heat from the noz-v zle-valvc chest is not imparted to it. By keeping the temperature of the relay-valve chcst down the troubles due to overheating are reduced to a minimum. To each relay} valvc is attached a stem 43, which passes through to the cover30 and the projection thereon and terminatesin a head that is' adapted to receive. the lower end of the com; pression-spring 44. The lower end of the spring is secured to the headby any suitablenon-alincmcnt ol' the parts is prevented. On

the lcl't-hand side of the valve-chest is an upright 41;. that carries the lulcruml'or the honzontall -extending lever 47. The outer end of the ever is provided with an ahtifrictionroller that engages with a projection 48 on the cam-roller. On the lever at the point directly over the cap 45 is a rojection which en ages with the latter or actuating it. Bo ted or otherwise secured to the righthand side of the relay-valve chest are two or more uprights 49, that carry bearin s for the opposite direction by'anextension-spring 53,

turbineshaft.

which is attached to one end of the band and to a stationary abutment, the said band being suitably secured to the roller. As the position of the balls changes, due to changes in speed, the cam-cylinder is rocked forward or backward, as occasion demands. Under normal load conditions certain of the relay valves will be depressed, certain of the other valves will be in a raised position, and one valve will be doing the governing. From this it follows that certain of the nozzlevalves will. be closed, while others are open, and that one nozzle-valve is opening and closing to govern the machine. The camcylinder isso arranged that all the nozzlevalves may be cut into or out of service.

i In Fig. 4 are shown two cam-cylinders 48, which are located on opposite sides of the On one end of each cylinder is a gear or pulley 50, that is connected to the corresponding gear or pulley on the opposite cam cylinder by a chain or belt 51. By means of this arrangement motion imparted to one cylinder is transmitted to the opposite cylinder. It is referable to so arrange the projections on the cam-cylinders that a nozzle-valve will first open on one side of the machine-and a second nozzle-valve open on the opposite side of the machine, and so on. To state the matter in a different way, the projections on the two .cylinders are staggered. In this manner the load is distributed evenly over the wheel. If desired, however,

several nozzle-valves may be operated suc-v cessively in one group, and then some or all of the valves in the second group, after which the valves in the first group will be acted upon by the governor.

Assuming the parts to be in the position shown, the nozzle-valve 19 is supposed to be in the act of opening and the cam-cylinder has depressed the relay-valve 28. The su ply of high-pressure fluid to the back of t e motor-piston is now cut 0H and the relayvalve has been moved away from the seat 31, which controls the passage of theexhaust. The steam which has been in the cylinderspace 17 and in the space within the barrel is now permitted to pass through the i e 40 and the passage 39 the direction ot itlie arrow and past the. valve 28 and its up er seat into the exhaust 33 in the direction 0 the arrow. This means that the pressures on opposite sides of the motor-piston are unbal anced, the pressure on the face adjacent to the steam-containing chamber 12 exceeding that on the u per side. As soon as the valve opens slight y the motor-piston is unbalanced to a greater degree, because the steam then has access to the under side of the valve. Hence its area is added to that of the piston. On the other hand, assuming that it was necessary to close one of the nozzle valves, the projection on the cam-cylinder would pass off of the roller on the actuating-lever 47 and the steam-pressure'on the under side of the valve 28 would cause it to rise with a jump and enga e the seat 31 and out off the passage to the exhaust. High-pressure steam would then pass from passa e 36 past the valve into passa e39 in the direction of the dotted arrow, t ence through the ipe 40 into the barrel of the nozzle-valve an motorpiston. The pressure exerted by the fluid plus that of the spring will start the valve into operation, and as soon as the passage 25 is uncovered the additional area ofthe piston thus ex osed is added to that already in service or moving the nozzle-valve toward its seat.

The nozzle-valve and the mechanism for actuating it form the subject-matter of a divisional application, which division was made subject to the requirement of the Patent O'fiice under the rovisions of Rules 41 and 42 and bears Seria No. 279,310, filed September 20, 1905.

In accordance with the provisions of the patent "statutes I have described the princivalves, a chest therefor separate from the nozzle-valve chest, conduits for conveying fluid from one chest to the other, and means for operating the relay-valves.

2. In a governing mechanism for elasticfluid turbines, the combination of a chest, a plurality of nozzle-valves. in the chest, pistons for moving the valves, relay-valves for controlling the pistons, levers for o )erating the relay-valves, and a yielding me ium between the valves'and the levers.

3. In a governing mechanism for elasticfluid turbines, the combination of a support,

'vers in their proper sequence.

a plurality of valves mounted therein, levers for'operating the valves, a cam which moves the levers in a predetermined manner, and an elastic medium between each valve and lever.

4. In a governing mechanism for elasticfluid turbines, the combination of a'nozzlevalve chest which is shaped to conform to that of" the casing, a relay-valve chest which is straight and which is separated from the nozzle-valve chest to prevent the transfer of heat, cam which extends parallel to the relay-valve chest, a plurality of valves in each chest, levers for operating the relay-valves which are moved by the cam, and motors under the control of the relay-valves for actuating the nozzle-valves.

5. In a governing mechanism for elasticfluid turbines, the combination of a chest containing nozzle-valves, a relay-valve chest supported in a definite position with relation to the n ozzlevalve chest but separated therefrom by a space to prevent the transfer of heat, a plurality of relay-valves for controlling the nozzle-valves, and a cam for actuating the relay-valves in the proper sequence which is supported by the r lay-valve chest.

6. In a governing mechanism for elastic? fluid turbines, the combination of a valve chest, a plurality of individual valves mounted therein, levers for actuating the valves, a spring carried by eachvalve-stem which. engages a lever, and a means for moving the le- 7. In a governing mechanism for elasticiluid turbines, the combination of a valvechest, a plurality of valves therein, a stem for each valve which extends through the chest, a plurality of levers which extend across the chest, a' yielding medium interposed between each stem and its lever, fulcrums for the levers located at one side'of the chest, and a means for actuating the levers located on the opposite'side of the chest.

8. In a governing mechanism for elasticfluid turbines, the combination of a valvechest, a plurality of valves each mounted in a separate opening, a cover for each opening through which the valve-stem extends, a yielding medium which is attached to each stem, levers-for actuating the valves that extend transversely of the chest, and a cam located at one side of the chest For actuating the levers. I

In a governing mechanism for elastic fluid. turbines, the combination of a chest con 1 .Witnesscs:

taining valves, means for actuating them, a second chest containing relay-valves, means for actuating the valves, conduits for conveyva ves for rendering the nozzle valves inoperative.

10. In agoverning mechanism for elasticfluid turbines, the combination of a chest containing valves, means for actuating them, a second chest containing relay-valves, a support for the second chest which separates it from the first to prevent the transfer of heat, conduits for conveying fluid from one chest to the other, and cut-out valves which interru t the passage of fluid from one chest to the other.

'11. In a governing mechanism for elasticfluid turbines, the combination of valves hich are divided into grou s and are arranged to open and close to a mit fluid to the turbine, cams for operating the valves arranged in sets, and means for transmitting motion from one set of cams to the other.

12. In a governing mechanism for elasticfluid turbines, the combination of valves which are divided into groups and are ar ranged to open and close to admit fluid to the turbine, cams for operating the valves ar ranged in sets, means for transmitting motion from one set of cams to'th e other, and a speed-responsive device for actuating one set of cams.

111 fluid between the chests, and cut-out 13. In a governing mechanism for elastic fluid turbines,,the combination of valves which are divided into groups and are arranged to open and close to admit fluid to the turbine, cam cylinders for operating the valves, means for driving one cylinderfrom the other, and a speed-responsive device for imparting movement to the cams.

14. In a governing mechanism forelasticfluid turbines, ,the combination of valves which are divided into groups and are arranged to open and close to admit fluid to the turbine, cams arranged in sets, the cams of the sets being staggered to actuate the valves in the groups alternately, and ameans for operating thecams. 5

In witness whereof I have hereunto set my hand this 4th day of April 904. i

WILLIAM 1;. a. EMMEP/ B. B. lll I.l.,' [Imam ()m onn.

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