US822887A

US822887A - Governing mechanism for elastic-fluid turbines.

Info

Publication number: US822887A
Authority: US
Inventors: William L R Emmet
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1904-04-05
Filing date: 1905-09-20
Publication date: 1906-06-05
Anticipated expiration: 1923-06-05

Description

Inventor;

PATBNTEDJUNB 5, 190e.

W. L. R. EMMET. Y GOVERNING MECHNISM PUR LASI'IG FLUID 1"UR13I'NBS.V

` nPIgIUATIoN Hum s321220. teer WlHiarn LREmmet. WM um I Il UNITED STATES PATENT OFFICE. i

WILLIAM L. R. EMMET, OF SOHENECTADY, NEW YORK, SSIGNOR TO GEN- ERAL ELEUIEIC COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANlSNi FOR ELASTiC-FLUID TURBINES.

Specification of Letters Patent.

Patented J une 5, 1906.

Original application filed April 5, 1904, Serial No. 201,74 'L Divided and this application tiled September 20, 1 B06. Serial No. 2 7 .3 l0.

,To @ZZ tvhom it, may concern:

Be it known that I, WILLIAM L. R. EMMET, a. citizen of the United States, residing at- Schencctad county of Schenectady, State of Newr Yor have invented certain new and useful lnlirovements in Governing' Mechanisms for astio-Fluid Turbines, of which the following is a specication.

The present invention is a division of my pending application, Serial No. 201,747, filed Afpril 5, 1904 and is made at the requirement o the United States Patent Office underthe provisions of Rules 41 and 42.

Certain types of turbines as commonly constructed arev provided with se aratelgyactuated nozzle-valves, each valve being/raei pablo of opening and closing inde endently of every other valve. Each nozz e-valve 1s operated by a {hdd-actuated motor, and in order to control the motors, and therefore the nozzle-valves,v a relay-valve is' provided for each motor, the relay-.valves in turn bei controlled by a device responsive to lolal ,changes-such, for exam le, as a flyhaii governor. Practice has emonstrated that owing to the. requenc with which the nozzlevalves are opened an closed by the motors the force exerted by each motor has a tendency to break the stem or connection netween it and the valve.

In order to'start the motors from a position of rest and in a direction to close the valve, springs are employed which are iocated between the head of the motoriston and the cylinder-head. I have foun that these springs are liable to lose their temper when subjected to euperheated steam or other Huid andalso that 'with the construetion heretoforeI employed they are too short unless the mechanism as a whole is made um duly large. Some difficulty has aise been experienced With rela -valves andthe mechamsm for operating t em.

The present invention has for its object to im rove the governing mechanism of eaeticfluid turbines by obviat' the ob'ections set forth above. The means whic these ob- 'ections are obviated will e set forth more iully hereinafter, to ether with certain other features of improv eonlttuctlen.

A In th ccomgmn drawings, which illustrate em n t of my invention, Figure 1 is an e sectional view through the valve vchest, nozzle -valve, iand relayprovided with a suitab valve mechanism, and Fig. 2 an enlarged sectional detail view of a relay-valve for con trolling the motor which actuates the nozzlevalve.

In practice the nozzles or fluid-disohar e passages are arranged in groups around t e `wheel-casing ofthe turbine an motive' iuid issuppliedto each group from a chest. These chests are segmental in horizontal section, so as to conform to thecurvature of the wheelcasing upon which they are supported.

1 represents a steam-chest ving a front or convex Wa 2, a rear or concave wall 3, and a iianged Vbase 4, by which latter it is bolted to the turbine-casing.' The chest is cored out to form a chamber 5, which contains the nozzle-valves.

Extending from the chamber are as many nozzle-passages 6 as there are nozzle-sections. These passages are formed in the projection 7, that constitutes an extension ofthe bottom Well of the chest. To the lower end of the projection is bolted or otherwise attached a nozgzie 8, comprising a plurality of closelyassociated nozz e-sections, each of which is providedlwith a well-rounded bowl 9 and a throat and discharge orifice of suitebie shape. These sections should have the same angle of deliveryl and the .same ratio of expansion Where expansion is necessary. Each assage 6 may supply one or more sections of t e noz sie as desired, and each nozzle-passage may and preferably docs cover. more than one bucket-space. Since the nozzle-valves -and their operating mechanism are duplicates e description of one of them will be sufficient.

The upler wall of the chest is bored out to form a. cy

inder 1() for the motor-piston 11,l .which opens and closes the nozzle-valve 12.

A removable seat 13 is provided that is car-'' ried by the lower part of the valve-chest. 14 represents the head of the clyinder, which is provided with an elongated projection 15, that enters the barrel 16, thatV connects the motor-piston 11 and the valve 12. The projection is provided with a vertically-extending) 1'?, which conveys high-pressure ul to e inside of the barrel. It is also provided with one or more transverse 'pass 18, which communicate with the vertipassage Y? and discharge steam into the cylinder 10 behind the piston. The piston is e packing-such for example as a plurality of grooves-an on the inside makes a close fit with the cylindricai surface on the upper end of the projec-V ICO therhest and bvreasonofitshavingconsidcrable length ii is not so liable to in inr)Y as a` short spring. lt is' also more reliabli` in operation. A-inf'e i1 i easier to lnalie a long spring with the desired scale than it is a lshort one. Situated in the c linder and above the piston is asprinir-plnll ffl. that serves to reduce the shin-li rausml by the opening ol the valve zo A\.s1hepi.-iton moves v.ip'\\'a.rdl and passes the ends ol ille transverse passage 1N n certain.

amount ol' motive lluid is trapped in the cylinder. whit-li lluirlacts as a cushion for (he opening valve.

ln order to control the opening and closing of tln` nozzle-valve: coi'res|mmling relayvalves )l are provided. cach valve being `mounted in a suitable. valve-clwst 2;. that is .straight in a longitudinal direction instead of 3o curved, like the -steam-chest. This is done in order that a single cani will be sull'ieient to operate all of the valves and also that the relay-Valves may be oi' cmresponding length. The relay-valve chest is provided with as many cylindrical penings as there are relayvalves and each opening is provided, with a head or cover '23, which has a projection on its under `side` the said projectign being provided with a valve-scat 24, Fig.` 2. Extend- 40 ing transversely and just abovt` the valveseat is a passage 25. thatlconnnunicates with the exhaust 2G. In addition to the transverse passage is a circumferential groove 27, that connects with the ends of the passage and opens into the exhaust. Situated below the projection on the cover and seated on the valve-chest is a detachable piece 2S, containing a valve-seat ZSJ for the lower end of the relay-valve 21 and also a vertically-extending passage 30, which communicates with the source of high pressurc--suchJ for example, as the pipe b1, Fig. 1, the latter being connected tothe chamber ln addition to the passage 30 two or more vertically-extend- 5 5 ing passages 32 are provided in the piece 28, which when the relay-valve 21 is raised from its seat admit high-pressure fluid into the passage 33, the latter being connected by the pipe 34, Fig. 1, with the passage 17 and the 6o upper side of the motor-piston. In the pipe 34 and in a position where it is readily accessible is a cut-off valve 35, by means of which any given motor and its nomic-valve can be eutinto or out of service.

The relay valve-chest is mounted on two or more Vposts 3G, which support it at a point lsome distance from the nozzle\alve chest. liv this arrznigement the parts are rendered easily accessible and the heat Vfrom the noz- YAle-valve chest is not imparted to ii. By keeping the temperature o1' the relay-valve chest down the troubles due to overheating are reduced to a minimum, To each relayvalve is attached a. stem 37, which passes up through to the cover 2li and the projection thereon and terminates vin a head that is adapted to receive and retain the lower end of the con)pression-spring 3S. The stein 57 `should be packed to prevent the escape of steam. in the present instance the stein passes through a long hole and the water collected in the space between it and the adjacent walls is relied upon to act as a waterpacking. The upper end of the spring 38 is attached to the cap 3l). 'lhe spring forms the only connection between the stem 37 and the cap El), and in this manner all trouble due to binding and non-alinexnent of the parts is prevented. Vhen the relay-valve is on its lower seat, only a relatively small area is exposed to the high-pressure steam; but as the lever 41 decreases the pressure on the spring by a certain a mount the steam-pressure thereon will be sufficient to start the valve, and since the exposed area Vsuddenly increases the valve will open with a sudden movement or jump, and thus prevent cutting of the valve or its seat. The reverse action takes place when the lever compresses the spring to a point where it overcomes the steam-pressure. This action is assisted by the shapes of the valve' and seats. On the left-hand side of the valve-chest is an upright 4U, that carries the Fulcrum for the horizontallv-ex'tending lever 41. The outer end ol' the lever is provided with an imtilriction-n)ller that engages with a projection A2 on the cam-roller. On the lever at the point directly over the cap 3) is a projection which engages with the latter for actuating it.

Bolted or othervsfwl secured to the righthand Side of the relay-valve chest are two or more uprights 43, that carry bearings for the rock-shaft or spindle or the cam-roller. The cam-roller is provided with projections of progressively-inereasing lengths to cause successive operation of the valves. It is actuated by a rack-and-pinion gearing 44, the rack of which is connected with the Speedresponsive device 15. The i eed-responsive device may be mounted on t e turbine-shaft or on another Shaft driven by the turbine through suitable intermediate mechanism. As the governor is brought into )la y, due to changes in speed, the cam-cylinder is rocked forward or backward as occasion demands. Und er normal load conditions rertainol therelay-valves will be depressed. certain of the other valves will be in a raised position, and one valve will be doing the governing. From IOO IIC