US2116385A - Elastic fluid governing mechanism - Google Patents

Description

y 3, 1938. R. H. COLLINGHAM 2,116,385

ELASTIC FLUID GOVERNING MECHANISM Filed Dec. 15, 1936 Inventor: Robert H. Col in ham by K Hi Attorney.

PatentedMay 3, 1938 I r i 2,116,385

ELASTIC FLUID GOVERNING MECHANISM Robert H. Collingham, RugbyQEngla-nd, assignor tcGeneral Electric Company, a corporation of New York 7 Application December 15, 1936, Serial No. 116,026

lln Great Britain December 17, 1935 1 Claim. (Cl. 137158) The present invention relates to elastic fluid Theright-hand end of the leverZfi' is pivoted to turbine governing mechanisms, more specifically a bellows 2'! and the left-hand end of the lever to the kind of governing mechanisms which con- 26 is connected by follow-up means including a trol the inlet valve of the turbine in response to link 28 and a forked member 28% to the sleeve I'I. changes in the vacuum of the turbine condenser. The bellows 21 communicates with the condenser 5 Such arrangements are important in order to pre- I2 through a pipe 29. The pressure in the belvent excessive blowing-01f from the boilers in case lows is counteracted by means of an adjustable it is necessary to disconnect the turbine from the spring 30. boiler during failure of the vacuum. During normal vacuum condition the bellows 0 The object of my invention is to provide an 2'! is in its maximum depressed condition and improved construction and arrangement for autothe pilot valve head 25 of the auxiliary pilot valve matically controlling the flow of elastic fluid to is in its bottom position so that no force is exerted turbines in response to pressure changes in the by oil pressure on the bottom of the sleeve II. exhaust, that is, in response to changes of the The latter then is held in its bottom position by vacuum in the condenser of such turbines. the action of a spring 3I. The pilot valve I6 may 15 This is accomplished in accordance with my be normally controlled by a speed governor 3Ia invention by the provision of an improved pilot connected to the valve I6 and the motor I3 by valve arrangement for controlling the flow of a fo ow-up lever 3") W th t arrangement actuating fluid to a servo-motor for moving the an increase in speed causes downward movement admission valve. The pilot valve according to of the left-hand end of the floating lever 3Ib and my invention has an element which is controlled consequently downward movement of the valve 20 in response to changes in vacuum in the conmember iii whereby communication is established denser to effect closing of the turbine inlet valve between the inlet port 20 and the conduit I5, peras the vacuum in the condenser drops, and vicemitting the supply of actuating fluid to the hyversa. draulic motor i3 and resulting in closing move- 5 For a better understanding of what I believe ment of the turbine inlet valve II. Similarly, a to be novel and my invention, attention is directed drop in spe causes opening m v m n of h to the following description and the claim apvalve II. As long as the sleeve I1 is in its lower pended thereto in connection with the accomposition, the governor 3Ia for normally controlpanying drawing which illustrates an embodiling the flow of elastic fluid to the turbine can 30 ment of a preferred arrangement of my invention. effect complete opemng of the admission valve I I.

The arrangement shown in the drawing com- If now for some reason the vacuum falls below a prises an elastic fluid turbine it which has an predetermined value fixed by the tension of the.

inlet valve II for controlling the flow of elastic spring 30, the bellows is expanded and thereby fluid thereto. The exhaust of the turbine is concauses upward or opening movement of the auxdensed in a condenser I2. The valve II is moved a y pilot V e 25 until actuating flu u d 35 by means of a servo-motor I3 to which actuating pressure is admitted to the chamber 22. This fluid such as oil is supplied by a pilot valve I4 causes upward movement of the sleeve II until connected to the servo-motor I3 by a conduit I5. the follow-up mechanism between the sleeve I1 The pilot valve M has a movable valve member and valve member 25 restores the auxiliary pilot 40 I6 disposed within a sleeve or bushing I1, which valve to its normal neutral position. Upward latter has a number of ports I8 and is movably movement of the sleeve I'I establishes connection disposed within a cylinder or casing I9. Actuatbetween the port 20 and the conduit I5 and thus ing fluid for operating the servo-motor or motors permits the flow of actuating fluid to the lower I3 is conducted to the pilot valve through port 20 part of the hydraulic cylinder I3. This efiects 45 and discharged therefrom through a port 2I. upward movement of the piston of the servo- The sleeve I1 and the lower portion of the casing motor I3, resulting in closing movement of the I9 form a chamber 22 to which oil or like actuatinlet valve I I and consequently a decreased flow ing fluid under pressure is conducted to effect of elastic fluid to the turbine Iii. The closing 5 movement of the sleeve. The flow of actuating movement of the inlet valve II is automatically 5 fluid to the chamber 22 and the discharge of fluid effected without any change in the main govertherefrom is controlled by an auxiliary pilot valve nor setting, not shown, and the portion of the 23 which has a casing 24 attached to the casing load thrown ofi by the setting may be transferred I9 and a movable valve member 25 with a stem to other turbines operating in parallel.

connected to an intermediate point of a lever 26. If the vacuum drops further, the operation de- 55 scribed above is repeated until the turbine is carrying such a load that any further reduction might cause dangerous heating of the low pressure end of the turbine. Preferably, therefore, the vacuum trip is set to operate automatically to effect shutting off of the steam supply at this load. Actuating fluid leaking along the outer surface of the sleeve is discharged through an opening 33 into a channel 34.

With my above invention I have accomplished an improved construction and arrangement of governing mechanism for elastic fluid turbines, especially useful in connection with arrangements where a plurality of turbo-alternators are connected to the same electrical system. My improved arrangement permits the reduction of the load of any particular turbo-alternator with infinite fineness of graduation.

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

An elastic fluid turbine arrangement including the combination of a turbine having an inlet valve for controlling the flow of actuating fluid thereto, a condenser for condensing elastic fluid exhausted from the turbine, and means for positioning the inlet valve in response to changes in vacuum in the condenser, said means comprising a servomotor for moving the valve, a pilot valve for the servo-motor, the pilot valve including a valve member, a sleeve forming ports and surrounding the valve member and a stationary casing surrounding the sleeve, the sleeve and the stationary casing forming a chamber, means for controlling the flow of actuating fluid to the chamber in response to changes in vacuum in the condenser to efiect movement of the sleeve, said means comprising an auxiliary pilot valve, a device responsive to changes in vacuum for moving the auxiliary pilot valve and a follow-up mechanism connected between the auxiliary pilot valve and the sleeve.

ROBERT H. COLLINGHAM.

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