US1553111A - Elastic-fluid turbine - Google Patents

Description

Sept. 8, 1925.

E. L. RICHARSCNv ELASTIC FLUID TURBINE Filed May l5, .1923 2 Sheets-Sheet 1 4J @SSL Sept. 8, 1925.

E.L.WCHARDSON ELASTIC FLUID TURBINE Filed May l5, 1923 2 Shees-Sheet 2 Inv ehbor 1 EIT-nest LRchardso'n,

His Attorheg Patented Sept. 8, 1925. Y'

UNITED STATES ERNEST L. RICHARDSON, F NARBERTH,

PENNSYLVANIA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

ELASTIG-FLUID TURBINE.

Application filed May 15,

To @ZZ w/uom t may concern:

Be it known that I, ERNEST L. BiermansoN, a citizen of the United States, residing at Narberth, in the county of Montgomery, State of Pennsylvania, have invented certain new and useful Improvements in Elastic-Fluid Turbines, of which the following is a specification.

The present invention relates to elastic fluid turbines of the'type in which elastic fluid is tapped from an intermediate stage for industrial purposes, such machin es being ordinarily termed extraction turbines, and has for its object` to provide an improved construction and arrangement in a machine of this character.

For a consideration of what I believe to be novel and my invention attention isdirected to the accompanying description and the claims appended thereto.

In the drawing, Fig. l is a `diagrammatic view partly in section of an elastic iluid turbine embodying my invention; Fig. 2 is a detail sectional view of certain parts; Fig. 3 is a transverse sectional view partly broken awa-y taken through the extraction stage of the turbine, and Fig. 4 is a detail longitudinal sectional view of a part of the turbine taken through one of the overilow or stage valves.

Referring to the drawing, indicates an elastic fluid turbine provided with an admission conduit 11 and a discharge conduit 12. Conduit 12 may be connected to a condenser in the well-known manner. In conduit l1 is a control valve 12a of any suitable type which is opened and closed by a fluid-actuated inotor 13 having its piston 14 connected to the stem l5 of valve 12a. The p-ilot valve of the fluid-actuated motor is indicated at 16 and its stem 17 is connected by a floating lever 18 and a link 19 to the governor lever 2O of speed governor 21 driven from the shaft of the turbine in the usual way.

' Floating lever 18 is connected at an intermediate point to valve stem thereby providing a usual form of follow-up device. The operation of a speed governor controlling a turbine admission valve through the intermediary of a. fluid actuated motor is well known and its operation well understood. The arrangement shown is to be taken as typical of any suitable arrangement for performing this function. Leading from an intermediate stage of the turbine is an 1923. Serial No. 639,207.

extraction conduit 22 through which elastic fluid of lower pressure may be drawn for industrial purposes.

In Fig. 4 the extraction stage is indicated by the reference letter A and the stage just beyond the extraction stage is indicated by the letter B. For example, A may be the lirst stage of the machine and B the second stage. Between turbine stages A and B is a diaphragm 23 provided with nozzles 24 through which elastic fluid is supplied to the bucket wheel 25 of turbine stage B. There are a number of groups of nozzles 24 as shown particularly in Fig. 3 and the admission of elastic l-uid to each group is controlled by a balanced valve 26 arranged in a steam chest 27, there being a steam chest for each group of nozzles 24 for supplying elastic lfluid to them. It will thus be seen that the ilow of elastic fluid from turbine stage A to turbine stage B is controlled by the several valves 26. The stems 28 of valves 26 project beyond the turbine casing and are provided at their outer ends with heads 29 provided with slots 30 in which are pivoted rollersy 31. Arranged between the outer ends o-f heads 29 and guide frames 32 are springs 33 which serve to bias valves 26 toward closed positions. Surrounding the turbine shell is a ring 34 carried on rollers 35 and passing through slots 30 in heads 29. On ring 34 are cams 36 adapted to engage rollers 31 for opening valves 26. As best shown in Fig. 3, the cams are arranged so as to successively open the valves,'the cam surfaces being spaced different distances away from the rollers. On ring 34 is a gear segment 37 which is engaged by a rack 38 carried on the lower end of the stem 39 of a fluid-actuated motor 40. The pilot valve of the fluid-actuated motor is indicated at 41 and comprises a casing 42 in which moves a valve stem 43 provided with the usual valve members 44 controlling the admission and discharge of actuating fluid to the main cylinder of the motor. The arrangement illustrated is a usual form of fluid-actuated motor, the operation of which is well understood.

Pilot valve stem 43 is connected to one end of a lever 45 pivoted on a fixed arm 46. The other end of lever 45 is connected by a rod 47 to the movable element of a pressure-responsive device here shown in the form of a flexible diaphragm 48 contained Cil in a casing 49. The casing 49 above diaphragm 48 is open to the atmosphere. rlhe casing below diaphragm 48 is connected by a pipe 50 to the extraction stage` ot the turbine. rThis means, therefore, that diaphragm a8 is subjected to the pressure existing at any time in the stage ot the turbine from which elastic fluid is being extracted for industrial purposes. On the outer end of rod 47 is a 'spring plug 5l with which is connected one 'end ot' a spring The other end of spring 52 is connected to a spring plug 53 which has threaded engage ment with screw threads 54; on a sleeve connected to the lower lend ot sleeve is a worm wheel 56 with which engages a worin 57 mounted on the shaft ot a reversing motor 58. With this arrangement it will be seen that when motor 5S is operated in one direction spring plug 53 will be moved upward to decrease the initial tension oi spring 52, while when operated in the other direction it will be moved downward to increase the initial tension on spring 52. ln this connection it will be noted that spring 52 is an extension spring in this instance. Motor 5S may be controlled manually or in any other suitable manner. According to one application of my invention, however, I preferably control it by means of mechanism responsive to the temperature in the apparatus to which extraction elastic 'fluid is supplied or to the temperature at any other desired point. To this end motor 58 is connected by lead wires 59 to a 'source of potential 60, the connections including a suitable reversing switch 5l which switch is adapted to be temperature controlled. in the present instance, l have illustrated diagrammatically an arrangement wherein the movable element of the switch is connected to an expansible diaphragm 62 which in turn is connected by a tube. 63 to a casing 63a which is subjected to the temperature at the point at which the. temperature is to be maintained constant. ln the present instance I have shown casing 63a located in the extraction conduit 22 at the point where it connects with al device to be heated. Tube 63 and casing` 63* are filled with a suitable liquid which as it expands and contracts due to temperature changes operates diaphragm 62 to release the connections of the reversing switch 6l. The tube G3 is made as short as possible for any particular instah lation and is suitably lagged to protect trom changes in room temperature., so that in substance the switch is operated by the expansion and contraction of the li .iid in casing 63'. Casing 63a is made sr iently large to give the desired operating range. AIt will be understood that the arrangement shown in the drawing is ot' a diagrammatic nature and that any suitable construction may be used 'for the purpose.

The operation ot the arrangement so tar described is as follows:

il ssunre that the turbine is ruiming and a certain amount ot elastic fluid is being extracted through conduit 22 tor industrial purposes, the remainder passing through valves 26 to the lower pressure stage-s ot the turbine. Some ot the valves 26 may be entirely open, another partly open, and others entirely closed. if now th-e pressure in the extraction stage A increases due, tor example, to the further opening ot valve l2, which may be caused by an increase in load on the turbine or a decrease in the demand for extraction steam, the pressure in the extraction stage will increase, thereby lifting diaphragm i8 against the action ot spring 52 and lowering pilot valve 4l so as to admit fluid pressure to the cylinder ot fluid-actuated motor l0 beneath the piston thereby moving the piston upward and turning ring 34e toward the lett as Iseen in Fig. 3. This opens further the stage valves 26 to permit more elastic fluid to pass 'to the` lower stages ot the turbine thereby decreasing the pressure in the extraction stage. On the other hand it the pressure in the extraction stag-e decreases below the desired value then a similar operation will taire place except in the opposite direction, valves 26 being closed to decrease the amount of elastic fluid which can flow from the `extraction stage. to the lower stages of the turbine and thereby increasing the pressure in the extraction stage. By 'this means the pressure in the extraction stage can be maintained substantially constant.

The pressure held by the fluid-actuated member i8 depends on the adjustment of spring 52 since it must operate against this spring in moving the pilot valve stem 43. As already stated, this spring may be arranged to be manually controlled it desired. N ith the temperature controlled arrangement shown in the drawing, in case the teinperature increases beyond a predetermind amount, reversing switch 6l will be moved to close circuit 59 to operate motor 58 in a direction to decrease the tension of spring 52 which means of course, that the extraction pressure is decreased. A decrease in the extraction pressure means, of course, that less elastic fluid will fiow to the heating device whereby less heat will be supplied to it. This is due to the fact that at any instant the resistance opposing the flow has a fixed value so that the amount of flow is a function of the pressure. On the other hand it the temperature falls too low, operation in the opposite direction will take place increasing the tension of spring` 52 and hence the extraction pressure and the flow of fluid to the heating device. Ot course with changes in pressure there is a change in the temperature of the elastic fluid extracted lll) but the amount is comparatively small for the pressures dealt with, the major effect in the temperature control being that due to increase and decrease in the amount of fluid supplied to the heating device due to the pressure changes. Y

When a change in stage pressure occurs in the extraction stage causing the valves 26 to open or close to admit more or less elastic fluid to the lower pressure stages of the turbine, the power ratio of the high pressure and low pressure stages is disturbed which requires that valve mechanism 12a be moved to admit more or less steam. In other words, assuming that the load on the turbine remains the same, if more elastic fluid is extracted the high pressure valve 12:l nust be opened somewhat in order to supply this additional elastic fluid, while if less elastic fluid is extracted, the high pressure valve mechanism 12a must be closed somewhat to decrease the amount of high pressure elastic fluid admitted to correspond to the lesser amount extracted. In order to control more promptly the operation of the high pressure valve mechanism 12a, when a change in the position of valves 26 takes place, I provide fluid-actuated motor 13 with an additional pilot valve 64, which is moved by pressure-responsive device 48. This additional pilot valve may be formed, with advantage, as a part of the pilot valve 41 and have its valve members 65 connected to the same pilotl valve stem 43. 66 and 67 are conduits connecting pilot valve 64 to the cylinder of fluid-actuated motor 13, the one connection being above piston 14l and the other below piston 14, in the usual manner. TWith this arrangement it will be seen that whenever pilot valve 41'is raised so as to admit motive fluid above the piston of motor 40 thereby moving the piston downV and valves 26 toward closed position, pilot valve 64 will be simultaneously raised so as to admit motive' fluid through pipe 66 to the underside of piston 14 to effect a corresponding opening movement of the high pressure valve mechanism so as to admit more elastic fluid to the turbine and thus maintain its speed. On the other hand, when pilot valve 41 is lowered to effect an opening movement of the valves 26 then pilot valve 64 will be simultaneously lowered to admit motive fluid through pipe 67 to the upper side of piston 14 to effect a closing` movement of the high pressure valve mechanism 12L thereby decreasing the amount of'elastic fluid admitted to the turbine. By this means valve mechanism 12a is controlled independently of the speed governor to take care of variations in the stage pressure due to the opening' and closing movements of valves 26. This means that the speed of the turbine can be maintained more nearly constant than would otherwise be the case.

In this connection it will be noted that whenV piston 14 moves in response to a movement Yof pilot valve 64, pilot valve 16 in a direction to eiect a counteracting movement of piston 14 thus effectingl an equalization of' pressure n opposite' sidesor" piston 14 pending a storing of pilotl valves 64 and 16 by the pressure responsive diaphra 'n 48 and governor 21 respectively. rIhis operation will be bestunderstood by a specific example. Assume that the machine is operating, the various parts being in bala ced positions with the pilot valves closed, and that decrease in the quantity of fluid extraction occurs which tends to increase the stage pressure. Diaphragm 48 is raised thereby lowering pilot valve 41 to effect an opening of the stage valves and a decrease in the stage pressure and also lowering pilot valve 64 to l effect a closing movement of valve 12Ll already explained, actuating fluid being admitted to the upper side of piston 14 through pipe 67 and discharged from the other side through pipe 66. As piston 14 moves downward it lowers pilot valve 16 so as to admit actuating fluid to the underside of pist-on 14 and permits it to discharge from the upper side, pilotv valve 16 thus operating eX- ctly oppositeto pilot valve 64. The pressures on opposite sides of piston 14 thus become balanced and the piston remains stationary pending the movements of the pilot valves back to normal positions by the speed governor and diaphragm. v

The use of internal balanced valves for cont-rolling the flow of elastic finid from the extraction stage to the next lower stage is of advantage in that it. enables elastic fluid of any desired pressure to be extracted without aiilecting the operation of the valves. rllhis is of particular utility when elastic fluid of high pressure is to be extracted for under such conditions if the valves not balanced it becomes very difficult to operate them. The use of an external ring' for operating the valves brings such mechanism Voutside the turbine shell where it is not subjected to diiiiculties arising from expansion and heating of the parts.

In accordance'with the provisions of the patent statutes, I have described the principle of' operation of' my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be. carried out by other means. K

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

1. In a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from a stage of intermediate pressure, a nozzle diaphragm between the it moves v ico extraction stage. and the next lower stage, a plurality of balanced valves controlling the flow of elastic fluid through said diaphragm, stems for said valves which pro-ject outside the turbine casing, and a ring surrounding the turbine casing and carrying means engaging the stems for opening said valves.

ln a multistage elastic fluid turbine, the combination of conduit for extracting elastic fluid from an intermediate stage, a diaphragm between the extraction stage and the next lower stage, a. plurality of groups oi nozzles in said diaphragm, separate balanced valves controlling the flow of elastic fluid to each group of nozzles, and means for successively opening and closing said valves.

3. ln a. n'iultistage elastic fluid turbine, the combination of a conduit for extracting elastic. fluid from an intermediate stage, a diaphragm between the extraction stage and the next lower stage, a plurality of groups of nozzles in said diaphragm, separate balanced valves contro-lling the flow of elastic 'luid to each group of nozzles, and cams located outside the turbine casing for successively opening and closing said valves.

l. ln a multistage elastic fluid turbine, the combination of a valve for admitting high pressure elastic fluid, al conduit for extracting elastic fluid from an intermediate stage, a valve controlling the flow of elastic fluid from the extraction stage to the next lower'stage, a fluid-actuated motor for each of said valves, a speed governor for actuating the motor for the first-named valve, and means responsive to the extraction stage pressure for actuating both said motors.

5. ln a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from. an intermediate stage, a diaphragm between the extraction stage and the next lower stage, a plurality of groups of nozzles in said diaphragms, separate balanced valves controlling the flow of elastic fluid to each group of nozzles, cams located outside the turbine casing for successively opening and closing said valves, and means responsive to the extraction stage pressure for moving said cams.

6. lin a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from an intermediate stage, a diaphragm between the extraction stage and the nex lower stage, al plurality of' groups of nozzles in said diaphragms, separate balanced valves controlling the flow of elastic fluid to each group of' nozzles, cams located outside the turbine casing for successively o-pening and closing said valves,

means responsive to the extraction stage pressure for moving said cams, and temperature responsive means for adjusting said pressure responsive means.

7. ln a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from an intermediate stage, valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, means responsive to the extraction stage pressure for operating said valve means, and temperature responsive means for adjusting the settino of said pressure responsive means. Y

8. In a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from a stage of intermediate pressure, a nozzle diaphragm between the extraction stage and the nextlower stage, a plurality of balanced valves controlling the flow of' elastic fluid through said diaphragm, stems for said valves which project outside the turbine casing, a ring surrounding the turbine casing and carrying means engaging the stems for opening said valves, a fluid-actuated motor for moving said ring, a movable abutment subjected to the extraction stage pressure for controlling said motor, a spring which opposes the movement of said abutment, and temperature responsive means for varying the setting of said spring.

9.*ln a multistage elastic fluid turbine, the combination of a conduit for extracting elastic fluid from an interni diate stage, valve means controlling the flow of elastic fluid from the extraction stage to the next lower stage, means responsive to the extraction stage pressure for operating said valve means, and temperature responsive means for modifying the action oi' the pressure responsive means on said valve means.

l0. rlhe combination with a multistage elastic fluid turbine, of a valve for admitting high pressure elastic Huid thereto, a conduit for extracting elastic fluid from an intermediate stage, valve means controlling the flow of elastic fluid through said conduit, a fluid-actuated device for moving said valve, a pilot valve controlling the flow of operating fluid thereto, a fluid-actuated device for moving said valve means, a. second pilot valve which controls the flow of operating fluid to both said fluid-actuated devices, and means responsive to a condition of the extracted elastic fluid for actuating said second pilot valve.

In witness whereof, l have hereunto set my hand this tenth day of May, i923.

ERNEST L. RCHARDSON.

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