US872377A

US872377A - Governing mechanism for turbines.

Info

Publication number: US872377A
Application number: US26321205A
Authority: US
Inventors: Frederick Samuelson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1905-06-01
Filing date: 1905-06-01
Publication date: 1907-12-03
Anticipated expiration: 1924-12-03

Description

PATENTED DEC, 3

APPLICATION FILED JUNEI, 1905.

/n ventor":

Witnesses:

eder/k Samue/son,

toll is connected by a pipe or passage with I UNITED s ATEs PATENT OFF FREDERICK SAMUELSON, OF RUGBY, ENGLAND ASSIGNOR TO GENERAL ELEOTB IGOOMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FORTURBINES.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed June 1, 1 905. Serial 1%. 263.212-

.To. all whom it may concern:

' Be it known that I, FREDERICK SAMUEL- the following is a specification.

This invention relates to the governing of elastic fluid turbines of the type describe'd in British Patent, No. 19,247 of 1896 in which the governing is eiiected by arying the quantity of steam delivered by the inlet nozzle or nozzles without change in the ratio' of expansion effected in the nozzles. In such turbines in order to work with the maximum economy under varying loads it is desirable to vary the capacity of the steam passage in the various stages of the machine "111 pro ortion to the variation in the qiiantity o steam admitted to the inlet nozzles for each load.

The purpose of this invention is to provide means for automatically accomplishing this object and to this end it'consists in providing motor operated valves controlling a portion of the inlets to one or more of the stages after the first and in causing these valves to be actuated automatically so as to maintain the desired pressures within the different stages ofthe machine. 4' I v v In carrying this invention into effect ac-' cording to one modification as applied to a tWO ,Stage turbine, I provide a number of slide valves. controlling a ortion of the inlet assageto the nozzles o the second stage. Each of these valves is normally held closed by means of a spring operating on one side of *a piston working in a closed'chamber fitted to the side of the turbine casing. The part of the chamberonthe other side of eachpisthe valve-controlled supplly chamber of one ormore inl'et nozzles of t e first stage'of the machine. The number of valves. provided on the second stage is arranged in accordance v with the load conditions to be fulfilled in practice."

Accordin to another modification, 'instead of a .shde valve for-controlling the inlet nozzles of the second stage I employ a iston valve. This .valve works in a chain )er or casingattached to the sideof the turbine and 7 controls -a passage between the exhaust of the first stage and a portion of the inlet nozzle supply chamber of the second stage.

, England, haveinvented cer-. 5 tam new an useful Improvements n Govermng Mechamsms for Turbines, of which binc,

This valve works verticallya'nd in its closed position is held up against its seat at the end .of a ring opening forming part of said passage by means of a spring. The spring is inclosed within a removable cap through the top of which an adjusting screw passes by means of which the spring pressure nay be regulated. i This cap also enables the valve to be readily removed from. its casing for examination or repair.

On the upper part-of the valve chamber;- directly above the/valve, is also fitted a cap forming the cylinder fora small piston the stem of which abuts against the top of the piston valve. The upper end of this chamber is connected to the supply chamber of an inlet nozzle or nozzle section by means of a pipe.

- When the steam supply to this'chamber is cut off the piston valve is held in its closed position by means of the spring but when steam is admitted to the first stage nozzlethe pressure passes to the small cylinder at the-top of the second stage valve casing,

forcing the small piston downwards and.

thereby opening the piston valve against the force of its controlling spring. Steam is thus admitted through the passage'from the first stage to the inletnozzlesof the second stage controlled by the piston valve, in accordance with the load condition.

The accompanying drawings illustrate means for carrying my invention into effect as ap lied to a two stage elastic fluid turure 1 being a sectional view of part of a tur ine in which the admission of fluid to the second stage is controlled by a valve operated by fluid from the inlet nozzle of the first stage; Fig. 2 is a similar view of a turbine in which the admission of fluid to. the

second stage is controlled bya iston valve which besidesbein o erated y the high pressure fluid as int c st modification'may. also on emergency be operated by the exhaust fluid from the first stage and Fig. 3 is a lan view of a vertical-shaft turbine showing the arrangement of the admission and stagevalve's'. 3

In carryin my invention into efiect according to t e modification illustrated in Fig. 1-, I provide an elastic 'fluid turbine ofthe type above referred to in which the velocity of .thefluid is extracted in two stages and caused to operate on two moving elements or wheels 1 and 2 arranged in separate chambers. Steam or other elastic fluid is admitted to the first stage through an inlet valve. 3 0i any well-known type and passes through the inlet nozzle f'to the wheel 1. After having passed tin -thigh and aperated on the wheel orwheels in the first stage the fluid passes through the nozzles?) into the second stage. Some of these nozzles 5 however are controlled by valves such as the slide valve 6 normally held closed by the action of a compression spring 7 surrounding the valve rod 8. p This valve rod passes into a hollow cylindrical casing 9 secured in any suitable manner in or formed integral with the turbine casing 10 and provided with a closing cap l1. Mounted within this cap on the 'end of the valve rod Sis a. iston 12 which slidingly fits the interior of t 1e casing 9 or cap 11 and against the inner side of which the spring 7 abuts so as normally to hold the valve 6 in its closed position. The interior of the casing 011 the opposite side of the piston from the spring is in communication through the pipe 13 with the fluid space 14 between the inlet valve 3 and the nozzle 4.01 the first stage. I 1 v It will be seen'from the above description that when the inlet valve 3 is closed, no fluid can pass through the pipe 13 to the outer side of the piston 12 and the spring will hold the piston in its outermost position there- .by maintaining the valve 6 closed. it however, the load on the turbine/be increased-so as to cause the valve 3 to open, some of the working fluid will pass through the pipe 13 to the interior of the casing 9 on the outer side of the piston. This fluid acting on the piston overcomes the pressure of the spring and causes the valve to uncover or partly uncover the inlet nozzle 5 of the second stage thereby -accommodating for the increased volume of. fluid admitted to the first stage,

by the opening of the valve 3, by providing increased passage area to the second stage. Itis to be understood that the valve 3 may only control the admission of fluid to one inlet nozzle or'to agroup of nozzles, and similarly, the valve6 may also control, one or a group of nozzles admitting fluid to the second stage of the turbine.

In the modification illustrated in Fig. 2,

' the valve controlling the admission of fluid from the first to the second stage is provided with a separate housing or casin 15 secured to the turbine casing. Inside t 's casing is a spring pressed piston valve 16 which is adapted to control the passage of fluid through a port 17 leading to the inlet'nozzles of the second stage. The upper end of this piston valve is directly in communication with the exhaust side of the first stage of the turbine through a port or passage 18 but the spring controlling it is so adjusted that normally it maintains the piston valve on its seat against the pressure of the exhaust. Should however'the pressure of the.

exhaust in the first stage rise beyond a predetermined amount the spring will be overcome causing the piston valve to move downwards and to uncover the passage to the nozzles oi" the second stage, thereby relieving the pressure of the exhaust Mounted. directly in line 'with the piston valve 16 is a cap or cylindrical casing 1.9 the lower end of which is open to the passage 18 and the made to open at any predetermined exhaustpressure. The operation of this modification 18 practically the same as zzescrihco above with reference to the first modification izz--- When valve 3 is opened toadmii more fluid: to the nozzles of the first stage. some of the fluid passes through the pipe 13 to the upper side .of the piston 20 causing it to move downward and withit the piston valve us through the pressure of the piston stem 21 on its upper side, therelry uncovering the port 17 and allowing fluid to pass from the exhaust'side-of the first stage through passage 1S and port 17 to the inlet nozzles ol the second stage.

Although I have descrihed my invention as applied to a two stage machine it villit'lze obvious. that it is equafly appiicahlc to the control of the various stages of a machine having more than two stages: it wizl fur ther he olivious that without departing from the spirit of the invention instead of actuating the stage controtling 'vaires 13y fluid pressure these valves may he otherwise automatically actuated. For example where the ya ives controllin the nozzles on the first stage are operateu by etectromagncts. S1111]- lar electromagnets may he conveniently employed for tiperating the valves lretween stages, the eiectromagnets of the first and succeeding stage valves lreing interlocked m a manner obvious to those skilled in the art.

In Fig. 3, which shows a plan view of a vertical-shaft turliine, 22 represents the governor-inclosing dome directly over the main shaft. Steam or other elastic fluid is admitted to the turbine by the branched conduit 23. Steam from the conduit enters the chests 24 containin the individual and sep arately actuated va.ves 3 which regulate the admission of motive fluid to the first-stage nozzles 4. 25 and 26 represent stage valves locatedi'n a-common casing which control the passage of steam or other motive fluid from the first to the second stage. These valves may be located directly under the admission valves or displaced therefrom. 27 and 28 represent stage valves located in independent casings Which control the passage The " and in what manner the same is to be performed, Ideclare that what I claim is 1 motive fluid through one of the stages, and a 'seat.

between two or more stages, said valve or va'l ves operating automatically 1n accordv of the first stage, substantially as described.

tiallyas described.

- creased or decreased as the conditions of servsaid valve receiving its operating fluid when hereinbefore referred to, a motor-operated of steam between successive sta es, as for The number of stages provided withthese valves can be inice'demand. Having now particularly described and ascertained the nature of my said invention 1, A turbine divided into stages with wheel. buckets for the sta es, in combination th a valve for controlling the passage of fluid actuated valve controlling the passage of motlve fluid through another stage, the

the' first mentioned valve moves from its 2. In a .multi-stage turbine of the type valve or valves controlling the fluid passage 'aiicje with the pressure within the valve controlled supply chamber of a nozzle or nozzles 3. in a multi-stage turbine, of the type hereinbefore referred to, a motor-operated valve or valves controlling the fluid passage between stages said valve or valves being normally held in the closed position by means of a spring and opened by means offluid pressure admitted from the supply chamber of a nozzle or nozzles of the first stage, substan- 4. A turbine comprising wheel buckets and fluid-discharging devices arranged in stages, in combination with a stage valve which is normally operated by hi h-pressure fluid but which opens automatica ly upon an increase in stage pressure above a certain amount. 5. A turbine comprising wheel buckets and fluiddischarging devlces arranged in stages, a stage valve which opens under a predetermined increase in stage pressure, a means for normally opening said valve by motive fluidfof a pressure above that of the stage, and a means for controlling the action of the motive fluid of higher pressure.

6. A turbine divided into stages, with wheel buckets and discharging devices fOll wheel buckets and dischargin.

' mentioned valves move from their seat.

7. A turbine divided into stages, with devices for the stages, admission valves 'or the hi hpressure stage, valves between stages whlch are normally governed by the admission valves, the said stage valves also opening in response to a definite increase in stage pressure, and means opposing the opening of the stage valves and causing them to operate successively.

8. A turbine comprising wheel buckets and fluid-discharging devices arranged in stages, in combination with admission valves, stage valves automatically opening under abnormal stage pressure, means responding to high pressure for normally opening the stage valves, and a device for closing each of the stage valves irrespective of whether it is opened by stage or high pressure.

9. A turbine divided into stages with wheel buckets for the stages, in combination with a valve controlling the passage of motive fluid through a stage, a second valve controlling the passage of motive fluid through another stage, a fluid actuated motor for moving the second valve in one direction, a mechanical motor for moving it in the opposite direction, and a conduit leading to the fluid actuated motor which i s controlled by the first mentioned valve.

10. A turbine divided into stages with wheel buckets for the stages, in combination with a nozzle, a controlling valve therefor, a stage nozzle, a stage valve controlling it, a fluid actuated motor for moving the stage valve in one direction, a spring for moving it in the opposite direction, and a conduit that communicates with the motor and the first