US1021257A - Automatic regulation of mixed-pressure turbines. - Google Patents

Description

E. W. MIX. AUTOMATIC REGULATION OF MIXED PRESSURE TURBINES. APPLIUATIONV FILED DEC. 14, 1910.

1 ,021 ,257, Patented Mar. 26, 1912.

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fWitne-Sses v inventor:

Edg ar' W. ix

Hisb ttorney 5E. W. MIX. AUTOMATIC REGULATION OF MIXED PRESSURE TURBINES.

- APPLICATION FILED DE-6:14, 1910. I a 1,021,257. Patented Mar. 26,1912.

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Inventor-'2 'Ecigo rW-..Mix,

, turbine which is normally supplied with UNITED STAT ES PATENT OFFICE.

EDGAR W. MIX, OF PARIS, FRANCE, ASSIGNO-R TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

Specification of Letters Patent.

MIXED-PRESSURE ITURLBINES.

Patented Mar. 26, 1912.

Application filed December 14, 1910. Serial No. 597,261.

To all whom it may concern Be it known that I, EDGAR VV. Mix, a citizen of the United States, reslding at Paris, France, have invented-certain new and useful Improvements in Automatlc Regulation of Mixed-Pressure Turbines, of which the following is a specification.

-Tl1is invention relates to systems otteeding a turbine, or other similar prime mover, with elastic fluid at different pressures and from different sources, commonly employed in what are known as mixed pressure turbines, that is to say, a

low pressure steam from the exhaust of a reciprocating engine or other source, but is also arrangedto'take steam at boiler pressure whenever there is a failure of the low pressure supply, or in case greater power is demanded from the turbine than it can produce with low pressure steam. Consequently, with an increasing load on'the tur-' bine, the regulating device should at first progressively open thelow pressure steam valve or valves to substantially full flow capacity, and when necessary it should then progressively open the high pressure valve 'or valves. Moreover, if the load remains constant, but the pressure or supply of the crease in the admission of high pressure steam, and furthermore that it shall if necessary produce a throttling of the low pressure steam in order to moderate the lower ing of its-pressure, and possibly to maintain it at or above a predetermined minimum pressure, especially if a steam acacumulator is'employed between the high pressure engine and. the low pressure turbine. It is very evident that the same regulating device should be capable of producing the reverse operation in case of diminu tion of the load, or of augmentation of the pressure of the low pressure steam or of the available quantity of this fluid. In short, the regulating device for controlling the admission of low pressure and high pressure steam will comprise two pieces of apparatus: ('1) Apparatus to maintain the speed constant notwithstanding the variations of load, including a speed. or load responsive device which shall suitably modify the total amount of the two fiuidsjad- Initted, acting in the same manner on the Such systems are admission of both, whatever may be the part performed by each fluid in furnishing en- Jergy to the turbine. (2) Apparatus depend out upon the pressure or the amount of lowpressure steam which, under the action. of the variations of these physical-quantities, will produce upon the members controlling the admission of the two fluids the same actions as those produced by the speed-responsive device under the action of variations of speed, in such a manner as to avoid, tor example, at constant load, the occurrence of a reduction of speed after a reduction of the ,lowpressure steam supply. At the same time this last apparatus will cause. the throt tling of the low pressure steam mentioned above. I

The drawings accompanying the present description showby way of example a device which may b'eemployed for the regulation of a mixed pressure turbine. .Itpermits the maintaining of constant speed (within the limits of the variation admissible between speed at no loada-nd speed under 'load) regardless of the part performed by each of the two fluids in furnishing energy; and it insures at the same time the maintenance of a suflicient minimum' pressure of the low-pressure supply. 7 p

In the drawings, Figure 1 is a diagrammatic view of a high pressure reciprocating engine, an accumulator receiving the exhaust steam, a low pressure turbine taking steam from said accumulator, and govern-- ing mechanism embodying my invention; Fig. 2 is a diagram of the governing mechanism showing it in-detail; and Fig. 3 shows a modification.

7 High pressure steam supplied the boiler 1 to the reciprocating or other high example, a balanced valve 6, the action of.

which is made dependent upon that of the speed governor 7 and permits the latter to maintain constant speed at variable load. When the amount of energy required of the turbine exceeds that which can be fur- The speed governor may control through a servonnotor 1.0 which may be, for

example, a servo-motor employing oil under pressure. The servo-motor 1.0 is furnished with a piston 11; which, by the use of a rack 12 and a gear 1 5, gives to a shaft 14 a limited movement of rotation. The shaft 14 carries on one end a helicoidal cam 15 which actuates the valve 6 through an elbow lever 16, and also carries cams such as that shown at 17, Fig. 2, which lift the valves 9 bythe assistance of levers 1.8 fulcrumed at 19. The cams are disposed in such a man ner that in its ascending movement the pis ton 11 causes first the opening of the valve 6 and then that of the valves 9 in succes sion. The valves are closed in the reverse order. The servo-motor is controlled by a piston-valve 2O placed so as'to be controlled by the speed governor 7through the levers a b 0, cl e f connected-by the link b c.

It will be seen that a retardation of the turbine speed causes the lowering of the sleeve f of the speed governor 7 and, conse quently, causes the points 6 b a to be lowered since the points a and d are, temporarily at least, immovable and the lowering of a causes the admission of oil under pressure beneath he lower end of the piston 11. The latter th u rises producing, due to the movement of the point (2 about the point f, the

return of the valve 20 to the position of rest and prevents further movement of the piston 11. This action is repeated until the displacement of 11 is suflicient to open enough valves to cause the speed to become normal. It will be seen that these actions ,depend solely-upon the speed, if once for all thecams 15 and 17 have been fixed in such a relation that the high-pressure steam begins to be admitted starting from a certain opening for admitting low-pressure steam through the valve 6. i

In advance of the valve 6 is placed a throttling-device, for example, a throttle valve 21 which is dependent upon the pressure of the low-pressure steam, in order to reduce the delivery of this steam when its pressure ,falls; Different methods may be employed to control'this throttling arrangement. For example, observing that the steam in the accumulator is always saturated, that is to say, that its temperature depends solely upon its pressure, it is possible to control the throttle valve 21 by a metallic tlurrinouuder or an oxpansiblo liquid or volatile liquid or gas ihermonioloia it is also possible to make use ol a uiunoumter and a servoauolor, and this is what has been shown here. The manometer 22, oil' any desired type, may c nsist, for GXlLll'lPlG, of a vessel of variable ca ')aeity connected by the pipe 23 to the accumulator 3 and closed by a de'lormable wall 24; whose mo ement in one direction is opposed it necessary by a spring 25 and which controls through the lever g h 2' the valve 26 of the servo-motor When the pressure in the accumulator .l'alls the point 2' is lowered as well as the point 71, since the point 1 is, temporarily at least, iniinovablc; consequently, the valve 26 causes the admission of oil below the piston 28 which. rises producing the closure, more or less complete, oi. the throttle valve 21. The iminoineler and its controlling lever (7 71 '6 cause the arrest of the lllOVtl'llCllt) ot the throttle valve 21 soon as the pressure ceases to diminish in the accumulator. The lowering of the pressure of the low-pressure steam carries with it a diu'iinution out the energy furnished by it to the turbine. If, moreover, the reduced low-pressure steam is throttled, we lessen still further the amount of energy furnished to the turbine. It is necessary therefore, in order to prevent a retardation of the turbine speed, to furnish.

a certain amount of higlrprcssru-e steam,

that .is to say, that the high-pressure aclmission valve or valves) be opened as it would be opened under the control of the speed governor in case of retardation. A simple means of obtaining this result is to substitute the action of the manometer for that of the speed governor on the-admission controlling mechanism. result, it is only necessary to, arrange between the speed governor and the valveQO a connection which maybe actuated either by the speed governor or bythe manometer (or by a member the movements of which reproduce those of the manometer). This is what is indicated in the drawings.

The lever a. b is controlled by its con nectio'n to the speed governor at the point .1), and by its connection atthe point 0 to a To obtain this the servo-mot0r 27, which correspond to those of the diaphragm of the manometer 22. It will be seen that through the levers 29, 30 and the links 31, 32, a diminution of pressure at constant speed would produce on the valve '20 the same. downward dis placement by moving up the end 0 of the le-vera b c as would be produced by the speed governor acting on the point 6 when displacements of the speed governor andthe manometer, while preserving the independcnce. of these devices, it is clear that the manometer may be made to act directly .-upon the lever a 0, as shown in Fig. 3, and

then to control directly the servo-motor 27-, or even'to employ for this control "a secondmanometer (or thermometer).

- In accordance with the provisions of the patent statutes, I have describedthe prin cipleof operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that, the invention can be carried out bypther means.

1 VVhat-I claim as new and desire to secure by Letters Patent of'the United States, is,-

1 Means for regulating a mixed pressure turbine,;comprising a valve'admit-ting low-pressure steam, a valve admitting highpres'sure steam, means including a device responsive. to the speed of the turbine for opening said valves in successive order, a

throttle valve for the low-pressure steam,"

and means for actuating said throttle valve responsive to variations in the pressure of the low-pressure steam. i

2. Means for regulating a mixed pressure turbine, comprising a valve admit-ting 'low pressure steam, a valve admitting highpreSSI re steam, a throttle valve for the lowpressure steam, means for actuating said throttle valve responsive to variations in the pressure of the low pressure steam, and

means whereby said low-pressure responsive means also controls both admission valves.

3. Means for regulating a mixed pressure turbine,-com prising a valve admitting highpressure steam, a valve admitting low-pres sure steam, a speed responsive de'vicegcontrolling both of said valves, a throttlelvalve for the low-pressure steam, means for actuating said throttle valve responsive to a drop in pressure of the low-pressure steam, and means whereby sa1d low-pressure responsive means also controls both admissionvalves independently of the speed-responsive device.

4. Means for regulating a mixed pressure turbine, consisting of a valve admitting loW-. pressure steam, a valve admitting. high-.'

pressure steam, a motor for operating both valves in succession, a speed-respons1ve device' controlling saidmotor, a valve for con trolling the communication between the first valve and its source of supply, and a dev ce responsive to variations in the low-pressure steam for controlling the last valve and also exerting a control of said. motor independently of the speed-responsive device.

5. Means for governing 'a mixed pressure turbine, comprising a valve for regulating the admission of high-pressure steam, a valve for regulating the admission of lowpressure steam, a speed responsive device.

that controls both valves, a valve for controlling the communication betweenthe lowpressure valve and its source of supply, a device responsive'to the pressure of the lowpressure steam from said source for controlling the last valve, and'means whereby said pressure responsive device also controls the two admission valves.

6. Means for governing a mixed pressure turbine, comprising a valve for regulating the admission of high-pressure steam, a valve for regulating the admission of low-pressure steam, means including a speed responsive device that opens the low -.pressure valve first and then opens the high-pressure valve to supplement the low-pressure supply when necessary, a valve controlling the communi-- cation between the low-pressure valve and its source of supply, and a device responsive to the pressure of the low-pressure steam that controls, all three valves.

7. Means for governing a mixed pressure turbine, comprising a; valve,for regulating the admission of high-pressure steam, a,

valve for regulating the admission of lowpressure steam, a motor for actuating the valves, a controller for the motorfla speed governor that acts on .the controller, a valve for controlling the communication between the low pressure valve and its source of supply, a device responsive to the pressure of the low-pressure steam from said source for controlling the last valve, and means whereby said pressure responsive device also acts on the controller.

In witness whereof, I have hereunto set my hand. EDGAR W. MIX.

Wit-nessesz' L WERNERHILDEBRAND,

C. Coxn.

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