US1514986A - Method of operating gas-steam turbines - Google Patents

Description

Nov. 11, 1924- H. G. NISSEN METHOD OF OPERATING GAS STEAM TURBINES Filed July 23. 1920 WWI lizvezzi fifZSG/VZS flz /arny Patented Nov. 11, 1924.

STATES PATENT HANS G. NISSEN, OF BERLIN-STEGLITZ, GERMANY.

Application filed Judy 23, 1920. Serial No. 398,571.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1318.)

To all whom it may concern:

Be it known that I, HANS G. NISSEN, citizen of the Republic of Germany, residing at Berlin-Steglitz', Germany, have in" vented certain new and useful Improvements in Methods of Operating Gas-Steam Turbines (for which I have filed applications in Germany Dec. 3, 1913, Patent No. 319,951, and in England July 2, 1920, Patent No. 146,387), of which the followlng 1s a specification.

The present invention relates to a method of controlling gas-steam turbines, which consists in placing the steam space in communication with the combustion chamber concomitantly with the explosion of the gaseous fuel and more particularly in turbines wherein the heatproduced by the explosion of the gas mixture 1s, partly, conducted to a medium which is used to cool the explosion chamber, for the purpose of thereby producing steam.

I-Ieretofore, it has been proposed to supply steam and an explosive air-gas mixture to the combustion chamber in such a manner that the steam is conducted into the combustion chamber, only after the products of combustion therein are expanded to the entrance pressure of the steamy In such arrangements, the steam would have a duplex function, namely, to raise the output of the turbine, by keeping the changes in the velocity of the escaping fiuid acting on the turbine blades as low as ossible, and to r0- tect the vanes of the tur ine against a anerous overheating. Engines so arranged do not however, operate' with the degree of efficiency which is to be desired, This is probably because, in impact turbines the exhaust velocity increases with the tempera ture, and the pressure of the exhausting medium causes a substantial part of the heat of the products of combustion to pass into the vanes without beingutilized, and because in such arrangements the exchange of heat between the steam and the combustion gases is imperfect only, due to the fact that the products of combustion have expanded to entrance ressure of the steam at the moment when t e steam is introduced, and the temperature has, therefore dropped considerably. The steam will not be superheated to any appreciable extent.

I have found however, that if the steam which follows behind the combustion gases,

as the latter escape is superheated by direct contact with the internal walls of the combustion chamber. The outputof the turbine will therefore be further increased.

By reason of the simultaneous expansion of both media the cycle of operation of the turbine is both simplified and accelerated. This permits the construction of the turbine to be materially simplified because only a single Valve need be provided, and this is operated only once during each cycle. Further, the valve may be self-actin For carrying out the method 0% the present invention, a valve is provided between the combustion chamber and the steam and gas mixing chamber, respectively, to connect the combustion chamber with the gasmixing chamber during the charging period and simultaneously maintain the steam chamber out of communication with the combustion chamber, and, at the moment of explosion, to connect the explosion chamber with the steam chamber and simultaneously cut-ofi' the gas-mixing chamber. The combustion chamber is separated from the valve and consequently from the gas-mixing chamber by a long, narrow passage so as to protect the latter against the da-n erous ef fects of the high temperature of t e explosion gases.

The present invention also comprises means for carrying out the method herein disclosed.

In the accompanying drawings which show a constructional form of gas-steam'turbine according to the present invention by Way of example,

Figurel is a Vertical section through the respective parts of the turbine.

Fig. 2- is a section on the line 2-2 in Fig. 1. r

Fig. 3 is a detail showing the mouth of the combustion chamber and the turbine vanes in section.

As shown in Fig. 1, to the casing 1 of the turbine is fixed a combustion chamber 2. This casing 1 is so constructed as to provide a water jacket 3 surrounding the combustion chamber 2, the latter being provided with webs 1 to facilitate the conduction of heat from the combustion chamber to the water in the jacket 3, and this may be further increased by providing at the rear end of the combustion chamber 2, transverse tubes 5 through which the water may flow. The water chambers communicate by means of a non-return valve 6 with a supply-water chamber 7 which is kept properly filled by suitable means, such as a pump. The valve 6 is maintained closed by spring 6 the tension of whichmay be varied and which permits a flow from the chamber 7 to the water jacket 3 when the pressure in the latter lowers to a predetermined extent. Beyond the end of the cooling chamber 3, surrounding the combustion chamber, is disposed a collecting chamber 8 for the gas mixture. A pump P feeds the gas-and-air mixture un der pressure from the carbureter to this collecting chamber. In order to avoid difliculty in case the pump supplies more mix ture, and produces a higher pressure, than required, an overflow valve, not shown, may be provided in the collecting chamber 8, to conduct any excess of gas mixture back to the carbureter. Between the collecting chamber 8 and the combustion chamber is a non-return valve 9, to prevent passage of fluid back to the collecting chamber. The load on the non-return Valve is variable, so as to allow of adapting the pressure of the mixture to the various kinds of fuel. Located forwardly of the non-return valve 9 is a self-acting control valve 10 and casing 11 therefor, which connects the combustion chamber alternately with the gas mixture chamber 8 and the water or steam chamber 3, respectively. For preventing a dangerous overheating of the control valve 10, the neck of the combustion chamber is made lon and narrow.

T he arrangement of the control valves is as follows,-attention beingv called to Fig. 2 particularly The cylindrical, bored valve plug 10 is freely slidable in its casing 11, and has its terminal positions determined, on the side towards the explosion chamber 2 by means of stops 1.2, and on the side towards the mixture chamber 8 by its tapered end 13 engaging its seat 14:- The valve casing has longitudinal grooves 15 between which radial passages 16 are provided for connectifng the space inside the valve casing 11 with an annular chamber 17 surrounding the valve casing and having a pipe 18 which leads into the steam space above the water in the jacket 3. When the tapered end 13 of the valve is seated, the radial passages are open, permitting the steam produced in the water chamber to flow into the combustion chamber 2. When, however, the valve plug is engaged by the stops 12, the radial passages 16 are closed, but the valve seat 14 is open, the gas mixture being from the carbureter and is forced into the collecting chamber 8. As soon as the pressure is reached, which corresponds to the kind of fuel employed, the non-return valve 9 opens whereupon the gas mixture will force the valve plug 10 forwardly until engaged by the stop 12. The gas then flows around the plug and enters into the combustion chamber 2. At the moment, when the gas mixture reaches the sparking plug 19, which, in starting sparks continuously, it is ignited and explodes. The exploded gases now pass between the transverse tubes 5 and the ring of guide blades 20 of the turbine into the rotor 21, where they deliver their energy. The rotor is supported on a shaft 22. At the moment of the explosion, the control valve plug 10 is, by the pressure of the products of combustion, forced back against its seat 14, closing the same and opening the passages 16 of the valve chamber which communicate with the steam chamber of the cooling water jacket 3. The surplus of explosion heat is transmitted through the thin webbed wall and the transverse tubes 5 in the combustion chamber 2 to the cooling water. Therefore, there will be a continuous generation of steam.

Since the steam space and the combustion chamber communicate, the products of combustion and the steam will expand simultaneously, but each in its own place, the products of combustion passing through the turbine blades and the steam passing into the combustion chamber. "While passing throu h the combustion chamber 2 the steam wifi cool the inner walls thereof which are highly heated and will thereby be itself highly superheated. As soon as the steam in the cooling water jacket 3 has expanded so far that the pressure in the steam space and in the combustion chamber, respectively, is lower than the pressure in the gas mixture collecting chamber 8, the non-return valve 9 will open again causing the steam passages 16 to be closed; and the process is repeated in the same manner as above described. After the second or third cycle of operations the electric sparking plug 19 may be cut out since further explosions will then be produced by self ignition.

is the amount of water contained in the water jackets 3 is reduced by the generation and escape of steam, water is supplied through the self-acting non-return valves 6, so that the water level will remain constant. The valves 6, must, therefore, operate simultaneously with the stroke of the valves 9. As both must open against the pressure existing in the water acket their respective loads will obviously have to be identical.

I claim as my invention:

A gas-steam turbine, comprising a combustion chamber in communication with a rotor of the turbine; a fuel chamber, a water jacket surrounding said combustion chamber and forming a steam generator; a valve in the water jacket. and in direct com munication with both of said chambers and said water jacket; and tubes in said com bustion chamber communicating with said water jacket for generating steam therein, said valve being adapted to shut off the steam generator from communication with the combustion chamber while the fuel is fed into the combustion chamber, and shutting off the fuel supply concomitantly placing the combustion chamber in communication with the steam generator for the purpose of supplying a stream of energy to the rotor of the turbine.

In testimony whereof I have affixed my signature.

HANS G. NISSEN.

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