US2227980A - Mixed pressure extraction turbine plant - Google Patents

Description

55% QSQQ WHBQ k Er E 2 A. ROSCH MIXED PRESSURE EXTRACTION TURBINE PLANT Filed Sept. 19, 1939 Jan. 7, 1941.

Inventor:

Hls Attorney.

h C s O R P U h t P A Patented Jan. 7, 1941 I UNITED STATES 2,227,980 mxsn PRESSURE EXTRACTION TURBINE PLANT Arthur Bosch, Brieselang, near N auen, Germany,

assignor to General Electric Company, a corporation of New York Application September 19, 1939, Serial No. 295,688 In Germany February 17, 1939 3 Claims.

The present invention relates to mixed pressure extraction turbine plants including an elastic fluid turbine having a first stage to which elastic fluid is supplied from different sources and which also has an intermediate stage from which elastic fluid is extracted at a fixed pressure for heating, processing or some other industrial purpose. More specifically, the invention relates to the kind of arrangements in which the two sources of elastic fluid supply for the first stage comprise a Waste heat boiler and a normal boiler. In an arrangement of this kind it is desirable to use a maximum amount of fluid from the waste heat boiler and a minimum amount of elastic fluid from the normal boiler.

The object of my invention is to provide an improved construction and arrangement of turbine plants of the type above specified whereby such plants are automatically controlled normally to receive maximum amount of elastic fluid from the waste heat boiler and a minimum amount from the ordinary boiler.

For a consideration of What I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

The single figure of the drawing illustrates a mixed pressure extraction turbine power plant in accordance with my invention.

The arrangement comprises an elastic fluid turbine I6 which has an inlet stage connected to receive elastic fluid from a Waste heat boiler l I through a conduit I2 including a throttle valve I3 and from a normal boiler I4 through a conduit I5 including a throttle valve I6. An intermediate stage of the turbine is connected to ani extraction conduit H for conductin extraction fluid to a consumer, not shown. The flow of fluid from the intermediate stage to the lower turbine stages is controlled in normal manner by an inter-stage valve I8 whereby the pressure in the intermediate stage may be maintained constant during varying demand for extraction steam. Thus, if the demand for extraction steam increases, causing a drop in pressure in the conduit ll, the valve I8 is moved towards closing position as will be more fully described hereafter. The exhaust end of the turbine I3 is connected to a condenser I9 and the turbine shaft is coupled to drive an electric generator 20.

The arrangement includes a governing mechanism whereby the pressure in the extraction conduit I1 is normally maintained constant during varying load demand and the inlet valves I3 and I6 are controlled so that the turbine consumes primarily elastic fluid from the waste heatbciler II. The valves I3, IB and I6 are connected to hydraulic motors 2|, 22 and 23 respectively, each motor being controlled by a pilot valve 25, 2d and 26 respectively. The motor 22 with its pilot valve 24 is connected to a lever 21 which in turn is connected by a link 28 to the left-hand end of a main governor lever 29. The motor 2I with its pilot valve is connected to a lever 36 which has a right-hand end connected to an intermediate point of a link 3!. The upper end of the link 3| is connected to the'lefthand end of a lever 32' which has an intermediate point connected by a link 33 to the main lever 29; The motor 23 with its pilot valve 26 is connected to a lever 34 which has a left-hand end pivotally connected by a link 35 to the right-hand end of the lever 32. The link 35 has a cross-member 36 in cooperative relation with a stop 31,,1imiting upward movement of the link 35. The cross-member 36 engages the stop 31 when the valve I6 reaches its closing position. The lower end of the link 3| is connected by means including a iulcrumed lever 38 and a spring 39 to a pressure-responsive device 40, which latter has a pipe 4| connected to the discharge conduit I2 of the waste heat boiler ahead of the turbine inlet valve I3 as regards the direction of flow of fluid therethrough.

The right-hand end of the main lever 29 is connected by a link 42 and a fulcrumed lever 43 to a pressure-responsive device 44 which has a pipe 65 communicating with the extraction conduit H. An intermediate point of the main lever 29 is connected by a link 46 to a fulcrum lever 41, which latter has a left-hand end connected to a speed governor 48 driven from the turbine shaft.

The operation of the mechanism is as follows: An increase in speed due to a drop in mechanical load demand .on the turbine causes closing of the valves I3, I6, and I8, and, vice-versa, a drop in speed causes opening of these valves. More specifically, an increase in speed causes counterclockwise turning movement of the lever 4'! about its fulcrum whereby the lever 29 is moved upward about its right-hand end, thus causing upward movementof the links 28 and 33. Upward movement of the link 28 causes upward movement of the pilot valve heads 24 whereby operating fluid under pressure is supplied to the upper part of the motor 22 anddrained from the lower part, causing downward movement of the piston and resulting in closing movement of the valve IB. Upward movement of the link 33 similarly causes upward movement of the links 3I and 35 whereby the heads of the pilot valves 25, 26 are moved upward and cause supply of fluid under pressure to the upper portions of the motors 2| and 23 respectively and draining of fluid from the lower portions of these motors, thus resulting in closing movement of the valves l3 and I6.

Now closing movement of the valve I3, due

pressure in the conduit I2 causes, through the pressure-responsive device 40, downward movement of the lever 38 whereby the link 3| is moved downward through the intermediary of the spring 39 and effects downward movement of the pilot valve 25 whereby fluid under pressure is supplied to the lower part of the hydraulic motor 2I and discharged from the upper part thereof, resulting in opening movement of the turbine valve I3. Downward movement of the link 3I also causes turning movement of the lever 32 about its pivotal connection with the link 33 whereby the pilot valve 26 is moved upward to effect downward movement of the motor 23, resulting in closing movement of the turbine inlet valve I6.

Let us now assume that the demand for mechanical load from the turbine remains constant and the demand for elastic fluid from the extraction stage changes. An increasing demand for extraction fluid causes a drop in pressure in the conduit I'I whereby the pressure-responsive device 44, more specifically the diaphragm thereof, is moved upward and causes counter-clockwise turning movement of the lever 43 about its fulcrum. This in turn effects clockwise turning movement of the main lever 23 about its pivotal connection with the link 46, thus causing downward movement of the link 33 and upward movement of the link 28. Upward movement of link 28 causes similar upward movement of the pilot valve 24 to effect downward movement of the motor 22 and closing movement of the valve I8. Downward movement of the link 33 causes downward movement of the valves 25 and 26 to effect opening of both valves I3 and I6, as described above. In this case an increased amount of fluid will be supplied to the turbine through both conduits I2 and I5 to satisfy the demand for extraction fluid through the conduit I'I. Under this condition the mechanical load output remains constant. Opening of the valves I3 and I5, causing increased flow through the first part of the turbine, increases the mechanical load output from the first or high pressure part of the turbine, but the simultaneous closing of the interstage valve I8 reduces the flow of elastic fluid through the low pressure turbine part a corresponding amount. Increased flow of fluid through the conduit I2, due to opening of the valve I3, causes a drop in' pressure in the conduit I2 whereby the pressure-responsive device 40 moves the link 38 upward to effect closing of the valve I3 and opening of the valve I6. While it is desirable to use a maximum amount of elastic fluid from the waste heat boiler, it is at the same time desirable not to permit the pressure of the fluid supplied from the waste heat boiler to drop below a certain value. Thus, once the waste heat boiler supplies a maximum amount of elastic fluid, an increasing demand for elastic fluid has to be satisfied by the normal boiler I4.

A drop in demand for extraction steam causing an increase in pressure in the extraction conduit I'I effects clockwise turning of the lever 43 about its fulcrum whereby the link 42 is forced upward, effecting turning movement of the main lever 29 about its pivot with the link 46, thereby moving the link 28 downward and the link 33 updemand for extraction steam under such condition causes closing movement of the valve I3 and opening movement of the valve I8. More specifically a decrease in demand for the extraction steam causes: an increase in pressure in the conduit I'I whereby the pressure response device 44 effects clockwise turning movement of the fulcrumed lever 43. This causes counterclockwise movement of the lever 29 about its pivotal connection with the link 46 moving the link 28 downward and the link 33 upward whereby the lever 32 is turned counterclockwise about its left hand end. This operation will continue until the desired pressure has been reestablished in the extraction conduit IT. This results in opening movement of the valve I8 and closing movement of the valve I6.

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

1. Elastic fluid turbine plant comprising an elastic fluid turbine having a plurality of stages, a waste heat boiler, a conduit including a valve for conducting elastic fluid from the waste heat boiler to the first turbine stage, a normal boiler, a conduit including a valve for conducting elastic fluid from the normal boiler to the first turbine stage, a conduit connected to the turbine for extracting elastic fluid from an intermediate stage, means including a valve for controlling the flow of fluid from the intermediate stage to the lower stages, and a governing mechanism for automatically controlling the valves in response to speed changes and changes in demand for ex traction fluid, said mechanism including means normally to maintain the supply of elastic fluid from the waste heat boiler at a maximum and from the normal boiler at a minimum.

2. Elastic fluid turbine arrangement including a multistage elastic fluid turbine, a waste heat boiler, a conduit including a valve conducting elastic fluid from the waste heat boiler to the turbine, a normal boiler, a conduit including a valve for conducting elastic fluid from the normal boiler to the turbine, and a governing mechanism including pressure-responsive devices connected to an intermediate stage and to the first mentioned conduit ahead of the valve therein for controlling the valves inresponse to pressure changes in said first conduit and in the intermediate stage normally to maintain the pressure in the first conduit substantially constant.

3. Elastic fluid turbine arrangement including an extraction turbine having an inter-stage valve for controlling the extraction pressure, a waste heat boiler, a first conduit including a valve for conducting elastic fluid from the waste heat boiler to the turbine, a normal boiler, a second conduit including a valve for conducting elastic fluidfrom the normal boiler to the turnbine, and a governing mechanism for controlling said valves, said mechanism including a speed governor driven from the turbine, and devices responsive to the pressures in the extraction stage and in the first conduit normally to maintain the supply of elastic fluid from the waste heat boiler at a maximum and from the normal boiler at a minimum.

ARTHUR ROSCH.

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