US1806065A - Steam turbine apparatus - Google Patents

Description

May 19 1931. K. FREY 1,806,065

STEAM TURBINE APPARATUS File d March 4, 1926 Patented May 19, 1931 UNITE' STATES PAT NT-osmos- KARL FREY, OF ENNETBADEN, SVIITZERLAND, ASSIGNOR TO A. G. BROVJN BOVERI & CIR, OF BADEN, SWITZERLAND, A JOINT-STOCK COMPANY STEAM TURBINE APPARATUS I Application filed March 4, 1926, Serial No. 92,309, and in Germany March 20, 1925.

This invention relates to the operation of back-pressure turbines, and has to do with control of the exhaust pressure of the machine.

The general object of the invention is the provision of an arrangement which will control automatically the exhaust pressure conditions in such fashion as to avoid power losses and overheating incident to operation of the turbine under low load.

Other objects will be indicated or pointed out hereinafter, or will be obvious toone skilled in the art upon an understanding of the present disclosure.

In the drawings forming a part of this specification I show in diagrammatic fashion certain embodiments of the invention, but the same are presented for illustration only and are not to be regarded as exhaustive of JllQ structural forms the invention may take, or to be construed in any fashion to limit the appended claims short of the true and most comprehensive scope of the invention in the art. In sait drawings,

Fig. 1 is a diagrammatic representation of a sectional elevation of a turbine and control device, the scales of the two being disproportionate, and

Fig. 2 is a sectional elevation of an alter- 3 native arrangement of the control device.

lVhen back-pressure turbines are run light the friction of the steam and the consequent lost power and overheating become serious sources of trouble, particularly when the hack-pressure is high. The purpose of the present invention is to avoid this serious disadvantage without affecting the readiness of the turbine for immediate starting up.

According to the invention this is achieved by automatically disconnecting the turbine from the back-pressure pipe when running light or with a small quantity of steam only, and allowing it to work with a lower exhaust pressure. The exhaust may be to atmosphere or to a condensing apparatus if one is available. The change-over may be accomplished in various ways by means of valves on the turbine itself or in the exhaust pipe.

Fig. 1 shows a possible arrangement for controlling a valve of this kind. The valve casing a contains a disc valve 6 controlled by the piston (Z through the valve stem 0. The space above the piston d communicates by means of a pipe 6 with the interior of the turbine T, preferably the first nozzle chamber 2?. When running with normal steam sup ply, the pressure on piston (Z' holds spring f compressed and valve disc Z) in the lower po-' sition shown dotted, placing the exhaust pipe 9 in communication with the back pressure connection it. Should the pressure in the admission chamber 6 fall consequent on the closing of the admission valve, the spring 7". beneath thepiston (Z isable to force the-disc b upwardsto the position shown, thus con necting the exhaust pipe 9 of the turbine to an auxiliary pipe i instead of to the back pressure pipe h. This auxiliary pipe'c ommunicates with thelower pressure. When the pressure in the nozzle chamber again rises, the piston (Z is forced down against the action of the spring f and the disc 6 returns. to its normal position.

lVhen the turbine is governed by hydraulic means suchv as an oil pressure regulator of the well known type in which the pressure of oil in a servo line is varied incident to changes of the engine speed, the piston (Z may, with advantage, be operated with the pressure oil, the change-over of the exhaust from back pressure to atmosphere or lower pressure he performed in the manner described above when the oil pressure in the servo systemfalls to a certain valueincident to decrease in load and steam admission to the engine.

iiccording to Fig. 2, the steam pressure in the nozzle chamber acts on the piston controlling, by means of the small valve Z, the pressure oil which is supplied by pipe m and operates the piston d. The oil is supplied from the oil pump on the turbine. Various other arrangements may be utilized for effecting the operative connection. The invention, it will be observed, qualifies the turbine to control its own back-pressure conditions so as to avoid interference from that source, with its effective operation.

What I claim is:

1. In apparatus of the character described, a fluid-pressure motor having a fluid-inlet and a fluid-outlet, means providing a plurality of fluid passages, valve means operable to provide for selective communication of said fluid outlet with said passages, and means responsive to high and low-pressure conditions at said fluid-inlet and being operable upon existence of such conditions to effect selecting action of said Valve means.

2. In apparatus of the character described, a fluid-pressure motor having a fluid-inlet and a fluid-outlet, means providing a plurality of fluid passages, valve means disposed for movement to a given position and being operable thereat toprovide for communication between said fluid-outlet and one of said passages and for movement to a different position and being operable thereat to provide for communication between said fluidoutlet and another of said passages, and means responsive to high and low-pressure conditions at said fluid-inlet and being operable at such high-pressure condition to effect movement of said valve means to said given position thereof and being operable at such low-pressure condition to effect movementof said valve means to said different position thereof.

3. In combination with'a fluid motor having an inlet for the flow of operating fluid of varying pressures thereto, and an outlet for the flow of fluid therefrom, of a plurality of passages for the flow of fluid from said outlet, and means responsive to variations in pressures of the operating fluid at said inlet for a selecting the passage for the flow of said fluid from said outlet. i

4. In combination with a fluid motor having an inlet for the flow of operating fluid of varying pressures thereto, and an outlet for the flow of said fluid therefrom, of a plurality of passages for the flow of said fluid from said outlet, and means automatically operative responsive to variations in pressure of said fluid at said inlet to selectively permit the flow of said fluid from said outlet through said passages. V

In testimony whereof I have hereunto subscribed my name at Zurich, Switzerland on the 9th day of February, A. D. 1926.

KARL FREY.

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