US2379770A

US2379770A - Elastic fluid turbine

Info

Publication number: US2379770A
Application number: US532606A
Authority: US
Inventors: Glenn B Warren
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1944-04-25
Filing date: 1944-04-25
Publication date: 1945-07-03
Anticipated expiration: 1962-07-03

Description

G; B. WARREN ELASTIC FLUID TURBINE Filed April 25, 1944 f July 3, 1945.

Inventor: A Gle'nnB. Warren, by Wfl/y "M g His Attcvney Patented Juy 3, 1945 ELASTIC FLUID TURBINE Glenn B. Warren, Niskaynna, N. Y., assignor to General Electric ICompany, a corporation of New York Application April 25, 1944, Serial No. 532,606

3 Claims. (Cl. 253-39) The present invention relates to elastic iluid turbines of the type constructed and arranged for partial admission of elastic fluid to the first stage.

More specifically the invention relates to thekind of turbines which' have a valve chest with a plurality of valves therein loosely supported on an actuating bar for controlling the flow of fluid to a plurality of separate sections of a first stage bucket wheel. The several valves have valve stems loosely projecting through openings in the actuating bar. Ordinarily the valve chest is arranged on top of the turbine casing so that stops on the free ends'of the valve stems always engage the bar in the open valve position due to` gravity of the valve members. Difficulties are experienced with this kind of arrangement when the valve chest is arranged on the bottom as is the case, for example, when the turbine includes two chests, one on the bottom, and one on the top of the casing. In such case the use of ordinary valves loosely held on a bar in the bottom chest may lead to severe hammering during operation. Further the valves may drop down against the bar when in a, partially open position, and then not go up to the proper closing position immediately upon the bar being moved in the closing direction, with the result that when a certain position is reached, the valve will be sucked up instantly to the fully closed position by the differential steam pressure across the Valve disk.

, The object of my invention is to provide an improved type of elastic fluid turbine, as above specified, whereby the aforementioned drawback is substantially eliminated.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates a part of an elastic fluid turbine embodying my invention; Fig. 2 is a section along line 2 2 of Fig. 1; and Fig. 3 shows a part of Fig. 1 in a different operating position.

The turbine comprises a casing I0 having a lower half with a valve chest I I integrally formed therewith and having an inlet opening I2 for receiving elastic fluid and a plurality of outlet openings I3 forming valve seats leading to channels I4 for conducting elastic fluid from the chest to separate sections of a rst stage bucket ,wheel I5 secured to a shaft I6. 'I'he channels I4 are in part formed by the turbine casing I0 and in part by a nozzle member or section I1 which has a plurality of partitions I8 and a` row of nomle plates I9 for. directing elastic fluid towards the bucket wheel I5. The nozzle member I1 in the present example is supported in the turbine casing and forced radially outward towards the valve chest by means of a plurality of radially disposed jack screws 20 secured to a ring or supporting member 2| which in turn is attached to the casing I0 by a plurality of axial bolts 22. 'I'his particular supporting arrangement for the nozzle section is more fully disclosed and claimed in the copending application of C. Fuerst, Serial Number 532,605, led on same date and assigned to the same assignee as the present application.

The lllow of elastic fluid from thevalve chest through the outlets I3 into the channels I4 is controlled by a valve mechanism including a separate valve 23 for each outlet opening I3. Each valve has a stem 24 with a nut or shoulder 25 at the outer end thereof. The stems 24 project loosely through openings 2E in an actuating member or bar 21. The bar 21 is actuated by means of two rods 28 having inner ends secured to the bar 21 and slidably projecting through openings I 28 in a cover 30 for the chest I2. The outer ends of the rods 28 are attached to the ends of a bar 3l which in turn may be moved .by means of a stem 32 attached thereto. 'Ihe stems 24 of the several valves 23 are of different lengths so that with the nuts 25 secured to the outer ends of the stems 24, different lost motion connections are formed -between the stems 24 and the bar 21, and during operation the valves 23 are opened successively. The valve with the shortest lost motion connection, in the present instance the shortest stem, will open first because its nut 25 is first engaged by the bar 21 upon downward movement thereof and the valve with the longest stem or longest lost motion connection with the bar 21 will open last because its stop or nut 25 is engaged last near the lower end position of the bar 21,

The arrangement so far described is known in the art. As pointed out above, difllculties are experienced when the valve chest is attached to ent example this means is in the form of a sep--l arate projection 33 for each valve 23 extending into the outlet opening I3 in the open valve position.

The projections 33 are of different lengths, depending upon and inversely proportional to the lengths of the respective lost motion connections between the valve stems and the bar 21. The length of the projection 33 of a valve is of the order of, preferably slightly greater than, the diierence between-the total movement or stroke of the bar 21 and the length of the lost motion connection between the particular valve and the bar 21. In the present instance the valve 23 at the left-hand end of the bar 21 has the shortest projection 33 and the longest lost motion connection between the stem and the bar 21. The valves attached to the center portion of the bar 21 have short lost motion connections but long projections 33. In closed position, Fig. l, all the projections 33 of the valves are located within the several channels I4 and with the valve mechanism in fully open position the several valves still extend into the outlets I3 of the chest. During operation the pressure in the outlets I3 and the channels I4 is lower than the pressure within the chest whereby a pressure drop is created along the valve which tends to force the valves towards the respective outlet opening I3, thereby maintaining engagement between the stops or nuts 25 and the bar 21 in the open position of any valve. In Fig. 3 all valves are open and all nuts 25 engage the lower side of the bar 21. The

force on the several valves created'by the pressure drop overcomes the force of gravity on the valve and forces each valve in the direction towards its seat. During opening operation the valve with the shortest lost motion connection opens rst. Once it is open, its stop or nut 25 is held firmly against the lower side of the bar 21. The valve with the longest lost motion connection opens last. During closing operation the valve with the longest lost motion connection and the shortest projection 3 3 closes rst and the valve with the shortest lost motion connection and the longest projection 33 closes last.

Thus, with my invention I have .accomplished an improved construction and arrangement of valve mechanisms including a plurality of separate valves disposed in the inlet chest of a turbine and having diierent lost motion connections with an actuating bar. The provision of means for creatnga pressure drop across the valves in the open position thereof assures rm engagement of the valve or valve members with the actuating bar in any position of the chest, particularly with the chest attached to the bottom of the turbine casing and the valves arranged in upside-down posiion.

thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Elastic iluid turbine having a casing, a valve chest with an inlet opening and a plurality of separate outlet openings attached to the casing, and a valve mechanism for controlling the ilow of elastic lluid through the several outlet openings comprising a bar disposed in the chest, a plurality of valves each having a stem loosely projecting through the bar and a stop at the outer end of the stem, the stems forming lost motion connections of different lengths with the bar, and

, means comprising an extension for each valve projecting into the respective openings in the fully open position of the valve to create a pressure drop across the several valves to maintain engagement between the stops and the bar in open valve position.

2. Elastic fluid turbine having a casing, a valve chest attached to the bottom of the casing and having an inlet opening for receiving elastic iluid and a plurality of outlet channels with valve seats, and a valve mechanism-for controlling the flow of elastic uid through said outlet channels comprising a plurality of valves each being cooperativelyiassociated 'with a seat and having a stem with al stop and a projection extending into the outlet channel, and means for actuating the valves comprising a bar having a. plurality of openings for loosely engaging the stems, the stems having different lengths and the stops thereon being arranged to eect successive openings of the valves upon actuation of said bar, and means for actuating the bar to open and close the valves, the projection of each valve having a length of the order of the difference between the total movement of the bar and the length of the lost motion connection of the particular valve.

3. Elastic iluid turbine having a casing, a chest attached to the bottom of the casing with an inlet :for receiving elastic fluid and a plurality of outlet channels for conducting uid to separate sections or a bucket wheel, and a valve mech- `anism for controlling the iiow of elastic iluid from channel and being of a length inversely proportional to the length of its lost motion connection with the bar in order to effect a pressure drop across the valve and maintain firm engagement Having described the method of operationA of my invention, together with the apparatus which I now consider to represent the best embodiment between the stops and the bar in the open valve GLENN B. WARREN.

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