US874936A - Governing mechanism for turbines. - Google Patents

Description

No. 874,936. PATENTED DEC. 31, 1907.

J. G. GALLAN.

GOVERNING MECHANISM FOR TURBINES.

APPLICATION FILED JUNE 16. 1906.

2 SHEETS-SHEET 1 I Witnesses: I hve nhor;

by war. k/f/fl o uiy.

John G. Ca |lar1,

Be-it known that I, JOHN UNITED STATES PATENT orrron.

' JOHN G. cALLAN,-or. LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC ooMPANY, A CORPORATION or NEW Yonx.

GOVERNING EcHANIsM Foa TURBINES.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Application filed J1me 16.1906. Serial No. 321,993.

To all whom it may concern: v

G. OALLAN, a

j citizen of the United States, residing-atLynn,

county of Essex," State-of Massachusetts, have invented ,certainnewand useful Improvements in Governing Mechanism for Turbines, cation. h

:The present invention is an improvement over the construction shown in my patent No. 845,448 dated Feb. 26, 1907. In the valve gear referred to in said application it was found under certain circumstances that the load on the shaft governor was somewhat greater, under certain c0nditions, than it should be for very close regulation, as for example, where the turbine was used to drive a generator for a lighting circuit. I'ngother words, it required a greater change in speed at times than is desirable for certain kinds of work although the actionof the mechanism as a whole was satisfactory.

The present invention has for its object to improve the construction of the governing mechanism referred to, and also governing mechanisms" of a similar nature, and make them more sensitive to load-changes by providing a means for supplementing .theaction of the shaft governor whereby the change in speed required to move the controlling valve or valves ofthe turbine is decreased.

In the accompanying drawings which-are illustrative of one of the embodiments of the invention, Figure '1 is a view partially-in section of a turbine and its controlling valves; Fig. 2 is an axial sect1on of the hydraulic notor for .moving. the controlling valves and taken on line 22 of Fig. 4., toshow the inlet port and passages; Fig. 3-is a similar secof Fig tion taken on line 3-3 of Fig. 4, to show the exhaust pprt and passages; Fig. 1 is a trans.- versesectlon of the motortaken on line 4-4 2 Fig. 5 is an enlarged sectional view show ng the, pilot valve and the auxiliary actuating mechanism in one of its positions; Fig. 6 is a similar view showing the valve in a slightlyd-ifferent position; and Fig. 7 is a'sectionalview showing a slight modification.

of which the following is a specifipiston being normally substantially balanced. cg linder 8 of the motor is suitably su The porte as by the head of the turbine. T e

iston rod 6 is packed at the point Where 1t passes through the head of the motor. Mounted within the rod andthe piston, is a pilot valve 9, the latter being connected by a rod 10 with the lever 1 1 of the shaft governor 12, which responds to speed variations.

The inner end of the pilot valve is bored out to receive the auxiliary or supplemental device 13 which 006 crates with the shaft governor to move t e pilot valve. This device functions as a piston, or plunger, for

moving the pilot valve,.and also as a valve to' partially regulate thepas'sageof fluid withinthe cylinder-under certain conditions to be referred to later;

The construction and a1? rangement of the motor is such that the motive fluid, oil in the present instance, flows continuously therethrough. Movement of I the piston in either direction is obtained by restricting'the flow of fluid at one point or the other in its passage. When restricted or stopped at one'point, the piston moves to the right, and when restricted or stopped at another point the iston moves to the left, it

being understood t lat when one side is under high pressure the other side is open to a reduced pressure or the exhaust.

Referring now to Fi s. 2 to 6, inclusive,

the pilot valve has heads .14 and 15 between which there is always fluid under high pressure, the. cylinder spaces on opposite sides of the iston being connected to the exhaust In Fig. 2 the heads are shown in their'central position-opposite the ports 16 and 17, and fluid can freely flow right and left'from the inlet 18 and connecting passage past the pilot valve heads, 14 and 15 into the passages 20 and 21, Fig. 3, thence into the axially extending passage 22, thence into the outlet 19.

So long as the load remains the same the shaft, the governor will move the pilot valve stem to the right, thehead of the pilot valveseating just before the head 14, Fig. 5.

As the pilot valve moves to the right from its central positionit first tends to restrict the flow of oil around its side, and this restriction increases the velocity because the fiow of oil through the motor is constant or substantially so. This increase of the piston, which in velocity of the fluid reacts on the valve and prevents it from closing readily, hence theload on the governor would be temporarily increased were it not for the auxiliary device 13 cooperating therewith. This movement of the pilot valve results man increase in pressure in the cylinder space on the left pressure acting on the stem 23 of the auxiliary device 13, moves it to the right and compresses the spring 24 situated at its opposite end and thus assists the governor. This relation of parts is illustrated in Fig. 5, and it is to be noted that the heads seat one after the other which reduces the effort required to move the valve. The disk 25 carried by the stem 23 also serves as a valve to restrict the flow of oil around the head 14 of the pilot valve, and this in turn causes a still greater pressure in the left-hand cylinder space until the pilot valve finally closes and the piston starts into motion I toward the right, and in so doing opens one motion of the or more admission valves through the medium of the lever 5, cross-head 4, etc.

As soon as the piston starts into motion, nd this irrespective of the direction of pilot valve, it will ultimately overtake the latter, and when a midor substantially mid-position is reached the parts will come to rest, as in Fig. 2, until there is a change in load.- In event of the admission valves 3, acting without substantial opposition, as would be the case where they were not held to their seats by the steam pressure -1n the inclosing chest, the auxiliary pilot valve will move back and forth in response to the governor, the auxiliary device doing little or nothing to assist inthe operation under these conditions.- Just as soon, however, as the load on the motor increases beyond a certain point, then the auxiliary device comes into service. The. auxiliary evice for assisting the governor works in one direction only, in the present embodiment of the invention, because itis only necessary to assist the governor when the motor has to raise a controlling valve or valves 3, against the steam pressure. g If conditions require it, however, I may arrange a device to assist the governor upon conditions of decreasing load.

Assuming that the effect of the spring 24 head on the right-hand piston, the central is not quite sufiicient to return the device 13 to its normal position when thepressure 1n the left-hand end of the cylinder falls to normal, it will be aided by the action of the fluid in the system acting on the disk 25.

I have illustrated my improvement in connection with one type of valve mechanism because it has been found to possess material advantages when used therewith, but the invention is applicable to governing mechanisms of different constructions.

In the figures described, the effect of the compression spring 24 is transmitted to the speed governor 12, it bein understood that norma ly the piston is he (1 in a fixed and balanced position by a body of ll( uid on each side thereof. ln'order to avoid this, a flat spring 26, Fig. 7, is provided and arranged to engage the left-hand end of the portion of the spring eing secured to the auxiliary device 13. The action of the mechanism is.the same as. described above only there is no tendency for the spring to continually urge the governor in one direction.

In accordance with the provisions of the patent statutes, I have described the. principle of operation of my invention, together with the apparatus which I now consider to represent'the best embodiment thereof; but I desire to have itunderstood that the appa ratus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new, and desire to secure by Letters Patent of the United States, is, 100

1. In a governing mechanism, the combination of a regulator, a governor controllin it, and a device which cooperates with an assists in moving the governor in its action on the regulator.

2. In a governing mechanism, the combination of a regulator, a motor for moving it,

a governor for controlling the movements of the motor, and a device'cooperating with the governor to reduce the load thereon as it con- 110 trols the motor.

3. In a governing mechanism, the combination of-a'regulatdr, a motor for moving it, a means for controlling the motor, a governor for varying the position of said means as the load requirements chan e, and a device cooperating with and reducing the load on the governor as it acts on said means.

4. In agoverning mechanism, the combination of a regulator, a hydraulic motor for moving it, a pilot valve controlling the motor, a governor regulating the movements of the pilot valve, and a device cooperating with the governor to move the pilot valve.

5. In a governing mechanism, the combi 12-5 nation of a regulator, a motor for moving it, a speed governor controlling the motor, and a device responding to unbalanced pressures for assisting the governor.

6; In a governing mechanism, the combination of a regulator, a hydraulic motor for moving it, comprising a piston, cylinder and locate in-the motor piston so that the latter 'anced pressures created will "follow up the movements of the valve, and a device set into 0 eration by unbaly a movement of .the pilot valve, which acts on the pilot valve in con'unction with thegovernor.

8. n a governing mechanism, the combination of a regulator, a motor for moving it, comprising a moving and a stationary element, a speed governor for controlling the motor, a device for assistin vthe governor in i its action on the motor, and a spring opposmovable element of the motor,-

9 In a governing mech it sm, the'combinat1on' of a regulator, a piston-and cylinder for moving it, a pilot valvefor governing the motor, a overnor for controlling the action.

of the ,pi ot valve, a device responding to" fluid pressure'changes for assis'tin the gov L Y evice which engages the piston; 1

ernor in its action on the pilot va ve, and a 5 ring for opposlngthe movements of'said.

10. In a governing mechanism, the combination of a regulator, a fluid-actuated motor for moving it through which the fluid continuou'sly flows, a valve for creating an unbalanced condition as to pressure on the movable element of the motor when it is desired tomove the regulator, a means for moving the ilot valve, and a fluid-actuated device whi'ccooperates with the said means.

11. In a governing mechanism, the combination of a regulator, a hydraulic motor for actuating it, a pilot valve for controlling the motor, which is provided with heads, ports cooperating with they valve heads, the relation of parts being such that one head closes its port before another .to reduce the load on the actuator, and an actuator for moving the pilot valve.

12. In a governing mechanism, the combination of a regulator, a means for moving it,

a sgei J. governor for controlling said means, mg the said devlce that'is carried by the an 7 which assists-in moving the governor when a device actuated by fluid under pressure the speed of .the apparatus being controlled Witnesses JOHN A.,MCMANUS, Jr., I HENRY O. WESTENDARP,

JOHN G. CALLAN.

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