US848106A - Governing mechanism for turbines. - Google Patents

Description

No. 848,106. 7 YPATENTED MAR. 26, 1907 0.JUNGGRBN. GOVERNING MECHANISM FOR TURBINES.

APPLIOA'IION FILED JULY 25, 1906.

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GOVERNING MECHANISM FOR TURBINES.

APPLICATION FILED J'ULY'25, 1906.

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GOVERNING MECHANISM FOR TURBINBS. APBLIOATION FILED JULY 25, 1906.

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PATBNTED MAR. 26, 1907.

citizen of the United and readiness of access and UNITED STATES PATENT OFFICE.

OSCAR JUN GGREN OF SCHENECTADY, NEW YORK, ASSIGN OR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR TURBINES.

Specification of Letters Patent.

Application filed July 25. 1906. Serial No. 327.596-

To all whom, it may concern:

Be it known that I, OSCAR JUNGGREN, a States, residing at Schenectady, county of Schenectady, State of New York, have invented certain newand useful Improvements in Governing Mechanism for Turbines, of which the following is a specification.

This invention relates to mechanism for governing the speed of-steam-turbines; and its object is to modify existing structures with a view to securing greater compactness alsg to lessen the weight.

A further object is to correct a tendency to hunt, which has been observed in prior structures of this kind. g

In carrying out my invention I rovide one or more sets of nozzlevalves, eac valve arranged to be operated by its own' individual cam and the cams for each set arranged to operate 1n succession. A fluid-pressure motor actuates the cams and a pilot-valve controls the motor, saidvalve being itself under the control of a speederesponsive device driven by the turbine. Follow-up mechanism restores the pilot valve to its normally closed position to pr'vent the turbine from surgin above or below normal speed/ In t e present invention there are two sets of nozzle -valves arranged, preferably, on opposite sides of the turbine and actuated bya single motor, one set remaining idle untifthe other set has been operated, or, if preferred, one or more valves in one set may operate alternately with oneor more valves in the other set. The motor consists of "ac linder and piston, the cylinder being re erably horizontal and arranged substantially. on a level with the valve chestsi The exhaust from the pilot-valve is controlled by an interrupting device-such, for example, as a.

spring-closed pop-valve preferably in con-j junction with an air-chamber, in order to' prevent too rapidan escape ofv the fluid, and

thus overcome any tendencybf the motor'to. The interrupting device causes the hunt. fluid to be discharged in periodical increments, thereby keeping the motor system in a slight tremble.

In the aecompan I drawings, Figure 1 is a side elevation oi an upright turbine em-, bodying myj invention, the. casing being broken away in order to show the parts on a large scale.

Fig. 2 is a-top plan view of the same, partly in section. Fig. 3 is a longitudinal section of the motor for operating the nozzle-valves. Fig. 4 is an end elevation of the same. Fig. 5 is a crosssection of the same through the pilot-valve. Fig. 6 is a vertical section of a nozzle-valve and its operating parts. Fig. 7 shows the antihunting devices. Figs. 8 and 9 show the two sets of cams in end view, and Fig. 10 is a top plan view of a modification.-

Only the upper part-of the casing 1 of the turbine is shown. Located above it and supporting the generator 2 is a stool 3. The upper end of the generator is closed in by a head 4, which is provided with a dome 5, that surrounds the shaft-governor and sup orts the lever for transmitting motion from t e speedresponsive device to theficontrolling or pilot valve or regulator of the hydraulic or fluidpressure motor. Situated at convenient points on the turbine-casing are the valvechests. There are preferably two of these chests 6 6', located diametrically op osite to each other. Supported in suitable earings on each chest is a rock-shaft 7 7, to which is secured a bevel-gear 8 8. A-shaft 9 extends across the machine, passing through openings in the wallsoi the stool 3 and journaled in bearings on the valve-chests and in brackets 10, extending from the rear end of the motor cylinder 11. .The cross-shaft carries bevel-gears 12 12, meshing with the gears 8 8. A spur-gear 13 is secured to the shaft between the brackets 10 and meshes with. a

rack 14, "which can be reciprocated by the piston 15, working in the cylinder 11, and thereby causes the shafts 9 7 7 to rotate.

On each shaft is a set of cams 16 16, disposed one slightly behind the other. Each ;can engages with a lever 17, fulcrumed at 18 ,in a frame 19, erected on the valve-chest,

ring 23, mounted in the .upper art of the ame 19. The stem 21v passest ough a suitable stuffing-box 24 in the removab e top ,of the chest. 4 When a valve is in the closed position, its lever rests in the cut-away portion of its cam,

the walls of which are substantially tangential to the hub of the cam, soas to givea quick opening movement to the valve. The

Patented March 26, 1907.

and engaging with a cross-head 20 on the stem 21 of a nozzle-valve22, which is held to its seat in the chest by a compression-s earns 16 are cut away much more than the earns 16, so that none of the former will .01)- erate until all of the latter have opened their respective valves, the two setsoperating in succession and not simultaneously. It preferred, however, the cams may be so cut and arranged that the valves will operate alternately on opposite sides ot' the machine.-

.-The piston 15 in the motor-cylinder 11 is actuated, preferably, by liquid-pressure from any suitable source, such as that which supplies lubricant' to the bearings. The liquid fills the cylinder on both sides of the piston,

so that the latter is locked and cannot move floating lever is adjustably pivoted to a rod.

33, by which it is connected through a bellcrank lever 34 and link 35 with the lollow-up v lever 36.

This latter is fulcrumed at 37 on a hanger 38, depending from a bracket 10, and its upper end is connected by a link 39 with the piston-rod or rack 14 of the motor.

When the speed-responsive device actuates the lever 32, it moves the floating lever,

whlch'fulcrums on the upper end of the 'rod 33. This rod is at that instant immovable because the parts to which it is connected are locked by the liquid in the cylinder. The

Inovementof the floating lever opens the pilot-valve, thereby admitting liquid-pressure to one side of the iston and allowing it to escape from the ot ier. The consequent movement of the piston rotates the shafts 9 7 7 and operates one or more of the nozzlevalves, thereby varying the supply of steam to the turbine to correct the abnormal speed which caused the governor to operate. This in ltself wouldcause the pilot-valve to close again, but not until the turbine had passed to a condition-of speed on the other side of. To avoid this hunting action,

the normal. the follow-up device operates to close the pilot-valve in advance of too much change in the speed of the turbine. As soon as the piston 15 begins to move the follow-up lever 36 is carried with it, and through the link 35 and bell-crank 34 moves the rod 33 lengthwise, which in turn actuates the fio ating lever and causes it to return the pilot-valve to its, normal closed position, thereby stopping the piston 15. By this device only so many of the nozzle-valves will be operated as are necessary to -effect the proper regulation of the speed of the turbine. In order to'control' these operations still further and prevent any hunting of the piston owing to toosudden a release of the'pressure on one side of it,

spring-valve and the motor.

I provide an interrupting device in the escapepipe 40, whereby the liquid is compelled to escape in spurts instead of continuously. One mode of producing this eil'ect is shown in Fig. 7, which is merely a diagram and does not represent the actual construction or arrangement of the parts. A valve 4] is interosed in the escape-pipe with a spring 42, liolding it normally closed. An air-chamber 43-is connected with the pipe between the The valve is constructed like a pop safety-valve, so that when it opens it will remain open for an appreciable time until the pressure due to the air compressed in the air-chamber has been considerably reduced. The valve will then close and remain closed until the liquid-pressure has compressed the air in the chamber to.a point where the valve will open again. In place of the pop-valve I may use any other equivalent device in which the valve is operated by inertiasuch, for instance, as the wellknown clack-valve of the hydraulic ram. In any event the result is an intermittent flow of liquid through the escape-pipe,

keeping the system in a tremble, so to speak, and preventing the motor from overrunning in either direction by causing the piston to movein a series of short steps instead of continuously.

Fig. 10 shows a modified arrangement in which the motor-cylinder is laced at right angles to the valve-chests wit its piston-rod 44 passing through both ends and extended at each end to carry a rack 45, meshing directly with a pinion 46 on the cam-shaft, which is lengthened out and supported in a bracket 47. This is a somewhat simpler construction than the other, though both .have been found satisfactory in actual ractice. One advantage of these is that all t 1e working parts are on the same level as the valves, and therefore within easy range of inspection and accessible'ior adjustment and repairj- Another advantage is that there are no working parts above or near the generator-casing, so that the latter is not disfigured by the oil and dirt, which to a certain extent are inevitably present on the working parts.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the a paratus which I now consider to re resent t 1e best embodiment thereof; but I esire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out b Y other means.

What I claimas new, and esire to secure by Letters Patent of the United States, is

1. In a governing mechanism for elasticfluid turbines, the combination with the turbine, of sets of nozzle-valves, a eannshaft for actuating each set of valves, a liquid-pressure motor located at about the level of said valves, connections between said motor and actuating'each set of valves, a transverse pressure motor for rotating said transverse 'terposed between them, two'valye-ch'ests on hydraulic motor mounted outside of and extending into said stool and connected said cam-shafts, and speed-responsive devlces controlling sa1dmotor.

2. In a governing devlce for elastic-fluid turbines, the combination with the turbine,

shaft geared to said cam-shafts, a liquid-' shaft, and controlling devices for said motor responsive to speed changes of the turbine.

4. In a governing mechanism, for elastic fluid turbines, the combination with the turbine-casing and the generator, of a stool in" opposite sides of said stool, a card-shafton each chest, a transverse shaft eared to said. cam-shafts and passing through said sto'ol, a

for said motor connected to said transverse shaft, and controlling devices the speed-governor of the turbine.

5. In a governing mechanism for elasticfluid turbines, the combination with mechanically-operated nozzle-valves, of a liquidpressure motor for operating them and means for causing said motor to o erate by an intermittent motion instead 0 continuously.-

6. In a governing mechanism for elasticfluid turbines, the combination with mechanically-operated nozzle-valves, of a" liquidressure motor for operating them, and means or periodically interrupting the escape of the liquid from the motor when working.

7. In a governing mechanism for elasticfl'uld turbines, the combination w1th mechanically-operated nozzle-valves, of a liquid pressure motor for operating them, means for causing said motor to o crate by an intermittent motion instead 0 continuously, comprising-a valve offering a predetermined resistance to movement, and an air-chamber.

In witness whereof I have hereunto set In hand this 23d'day of July, 1906;

OSCAR JUNGGREN.

Witnesses:

M BENJAMIN B. HULL,. .FRA-NK J. Donn.

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