US1213791A - Fluid-pressure engine. - Google Patents

Description

J. N. BAILEY.

FLUID PRESSURE ENGINE.

APPucATloN msn MAY I7, i909.'

Patente Jan. 23, 1917.

I II I I @I W9 I I INVENTOR,

Im. II@ @who-.l *im WITNESSES ORNEY IN FACT.

l,in the supply mains and JAMES NICOLSON BAILEY, OlE STRJETFORD tilt I ENGLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 THE COLONIAL TRUST COMPANY, TRUSTEE, 0F PITTSBURGH, PENNSYL- VANIA, CORPO t1 TION 0F PENNSYLVANIA.

' FLUID-PRESSURE ENGINE.

T0 all whom it may concern.'

Be it known that li, JAMES NICoLsoN BAILEY, a subject of the King of Great Britain, and a resident of Stretford, England, have made a new and useful Invention in Fluid-Pressure Engines, of which the following is a specication.

My invention relates to fluid pressure engines and in particular to valve mechanism for use in connection with machines of this description adapted to be driven by motive fluid supplied at relatively low pressure. ln cases in which the exhaust steam of a turbine or other machine, adapted to be driven by steam at high pressure, is utilized, it is desirable that the connection between the turbine and the exhaust main feeding the low pressure engine should be broken if the steam pressure in this main falls below a predetermined value, otherwise the vacuum which exists in the low pressure engine will work back into the supply mains, and when the' pressure in the supply mains is belowv the pressure of the atmosphere there is likely to be a considerable leakage of air into-these mains. lllhis air impairs the vacuum in the condenser so that the turbine calls for moresteam and the pressure in the mains is still further reduced. Moreover, in cases in which the exhaust steam from a reciprocating engine-is utilized it is possible that, if a vacuum exists in the reciprocating engine exhaust, that is to say in the mains leading to the low pressure machine, the engine may continue to run after the steam is cut 0H, thus rendering it impossible to obtain good intermittent working of the engine and cause damage by not stopping when anticipated.

According to this invention, ll provide a system of valves interposed between the low pressure engine and the exhaust mains leading from the exhaust of the high pressure turbine or reciprocating engine, so arranged that the inlet of steam to the low pressure engine depends upon the pressure existing a fall in the steam pressure below a predetermined limit operates to eut od connection between the low pressure engine and the exhaust mains of the high pressure turbine or reclprocating engine, thus obviating the disadvantages before explained.

The accompanying drawing is a diagram- Specication of Letters Patent.

Patented dan.. 23, 191W..

Application led May 17, 1909. Serial No. 496,621.

matic view of a, system of valve gear controlling the admission of steam to a low pressure engine arranged in accordance with my invention.

The low pressure engine 1 is shown supplied with fluid under pressure from the supply mains 2 leading to the exhaust of a high pressure engine. A stop valve 3 controls the supply of steam to the low pressure engine and preferably operates as a nonreturn valve. For this purpose the stem of the valve 3 is connected by means of a link 4 to a lever 5 fulcrumed at 6 and adapted by means of a weight 7 attached to one end of said lever to normally balance and maintain the valve 3 in an open position when the pressure before the valve 3 exceeds the pressure on the delivery side. The opposite end of the lever 5 is attached to the movable member of a dash pot 8 to prevent chattering of the valve. Located in the supply mains 2 between the valve 3 and the low pressure engine 1 is a valve 9 preferably of the two-seated type, so that the pressure existing on the undersideof said valve does not interfere with its operation. The stem of the valve 9.is pivotally connected to a double slotted link 10 connected by means of pins to two levers 11, 12 adapted to control the operation of said valve. The lever 12 is fulcrumed at 13 and is connected at one end to a link 13 attached to the stem 14 of a weighted piston 15 sliding within a cylinder 16. rlhe lower portion of the cylinder 16 is connected by means of pipe 17 to the low pressure mains 2 so that the pressure existing on the under side 0f said piston corresponds to the pressure existing in the supply mains 2. rlihe lever 12 is normally retained in an inoperative position, that is to say in a position in which the valve 9 will be permitted to open, by reason of the pressure existing on the underside of the piston l5 and the weight of the piston 15 is so determined that under normal conditions the pressure on the underside of said piston is sufficient to maintain the piston l5 in a raised position.

ln order to obtain a variation in the degree of pressure necessary to raise the piston 15 and permit the valve 9 to open, a spring 18 is provided adapted to increase or decrease the weight imposed upon the end of tached to the opposite end ofsaid leveris adapted to retain the. valve 9 in a closed position. The lever 11,y however, is connected by means of a link 21 to one arm of a bell crank lever 22 adapted to engage with .a trigger 23 which will maintain the lever 11 in an inoperative position against the action of the spring 20. The trigger 23 is adapted to be tripped when the speed of the low pressure engine has exceeded a predetermined degree by reason of the movable member 24 of a centrifugal governor 25 being brought into engagement therewith. Leading into the lower portion of the cylinder 16 in which the piston 15 works is a pipe 26 forming a siphon leading into a receptacle 26 with a suflicient head of water to prevent the pressure from the low pressure supply mains 2 escaping through the pipe-26, at the same time permitting the condensed steam to be withdrawn from said cylinder. Between the valve 9 and the low pressure engine 1 is a similar valve 27 the stem of which is connected by means of a link 28 to a governor (not shown) adapted to control the position 'of valve 27 and so to vary the amount of steam admitted to the low pressure engine in accordance with the load in the well known manner. Live steam from a reducing valve may be'admitted to the mains 2 through a branch pipe 30.

The operation of the apparatus is as follows: When the pressure in the supply mains 2 has fallen to an extent suilicient to enable the piston 15 to fall to the bottom of the cylinder 16, the lever 12 will be rotated and acting through the double slotted link 10 will close the valve 9. A similar closure of the valve 9 will follow when the speed of the low pressure engine has reached a predetermined rate suiicient to bring the movable member of the governor 25 into engagement with the trigger 23 the arm 22 will be released and permit the lever 11 to be rotated on its pivot under the action of the spring 20 which, as before explained, is normally maintained under tension, and the valve 9 will be closed. It will thus be seen that the valve 9 has two separate and `dis tinct functions, viz: to cut olii' the supply of steam to the low pressure engine when the pressure in the supply mains falls a predetermined amount, and also when the peed of the engine exceeds a predetermined lmit.

The invention is specially intended for application to low pressure turbines driven by exhaust steam, but may also be used in the case of reciprocating en 'nes and also with turbines designed to utllize both high and low pressure steam either separately or simultaneously but in the latter case the non-return valve 3 and stop valve may be dispensed with the engine supplying the steam to be used 1n the low pressure en (gine. It will be understoo that the particular construction of the valves is immaterial and various forms of valves and means for operating the same may be used without exceeding the scope of the invention.

Havl'ng now particularly described and ascertalned the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. In combination with a turbine, a su ply main, a valve for delivering motive fluid to the turbine, a governor for controlling the operation of the valve, a second valve between the main and the first mentioned valve, and means responsive to fluid ressure within the supply main for contro ling the operation of the second valve.

2. In combination with a turbine, a supply valve for delivering motive fluid to the turbine, a governor for controlling the operation of said valve, and a pressure responsive valve for controlling the delivery of motive fluid to said first mentioned valve.

3. In a low pressure turbine two independently actuated valves and their casings, the casing of one being in communication with the other, means for actuating one of the valves in response to the speed of the turbine, and means for causing the other valve to cut of the supply of iluid to the turbine when the pressure falls below a determined value.

4. In combination with a low ressure turbine, two independently actuate valves, the casings of which communicate with each other, means for actuating one of the valves in response to variations in the speed of the turbine, and means for causing the other valve to cut ofi the supply of fluid to the speed responsive valve when the pressure falls below a determined pressure. I

l5. In a iiuid pressure turbine, a supply main, a valve, a speed responsive device for controlling said valve tov determine the amount of steam admitted tosaid turbine, another valve normally unseated, and means for seating said last named valve when they pressure in the main falls below a determined value.

6. In a low pressure turbine, a supply main, a cut oil' valve in the supply main, a

maratea speed responsive device controlled valve for governing the amount of steam admitted to the turbine, and a valve in the main having a closing movement when the pressure in the main falls below a determined value.

7. lln combination with a low pressure turbine, two independently actuated valves for controlling the delivery of motive fluid to the turbine, a speed responsive governor for controlling the operation of one of said valves, a pressure responsive mechanism and an independent speed responsive device for controlling the operation of the other valve.

8. ln combination in a turbine, a fluid supply main, a load responsive valve for proportioning the delivery of fluid from said main to said turbine, a pressure actuated valve responsive to variations in the fluid pressure within said main for controlling the delivery of motive Huid to said iirst mentioned valve.

9. lin combination with a turbine, a motive fluid supply main, a load responsive valve for proportioning the delivery of motive fluid from said main to said turbine, a second valve for controlling the delivery of fluid from said main to said first valve, a system of operatin mechanisms for actuating said second va ve, a pressure responsive device for actuating said mechanisms, and a speed responsive device for actuating said mechanisms.

10. ln combination in a turbine, a Huid supply main, a load responsive valve for controlling delivery of Huid from the main to the turbine, a valve responsive to the pressure of Huid within the main for cutting off the supply of `fluid to the turbine when the pressure in the main falls below a determined pressure, a source of high pressure motive fluid communicating with the main, a source of low pressure motive fluid communicating with the main, and a non-return valve in the main between the point of communication with the source of high pressure motive fluid and the point of communication with the source of low pressure motive fluid. 11. lln combination with a low pressure turbine, a supply main communicating with the turbine, a load responsive valve for controlling the delivery of motive fluid from the main to the turbine, a cut-off valve for closing communication between the main and the turbine when the turbine exceeds a determined speed, a high pressure main communicating with the supply main, and a non-return valve in the supply main, between the point of communication with the high pressure main and the source of low pressure fluid. i

lln testimony whereof, I have yhereunto subscribed my name this 30th day of April,

JS NllCOLSN BAHJEY. itnesses:

JAS. Enma, JAS. STEWART BnoADFooT.

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