US957915A - Elastic-fluid turbine. - Google Patents

Description

E. THOMSON.

BLASTIG FLUID TURBINE'.

APPLIOATIQN FILED JULY a, 1907.

Wltmesses E. THOMSON.

.ELASTIG FLUID TURBINF APPLICATION FILED JULY 3, 1907.

Patented May 17, 1910.

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UNITED sTATEs PATENT AOFFICE.

'ELECTRIC COMPANY,

A CORPORATION F NEW YORK.

nLAsTrc-FLUID TURBINE.

To all whom it may concern:

1 3@ it known that I, ELrHU THOMSON, a citizen ofthe United States, residing at Swampscott, county of Essex, State of assachusetts, and useful Improvements in Elastic-Fluid Turbines, of whichfthe following is a specifrom the theoretical angles,

phase type.

ication.

My invention relates to elastic fluid turbines, and has for its object to improve their construction and at the saine time render them more eflicient.

In carrying out my invention in its simplest form two oppositely rotating bucketwheels contained in a casing are provided for the purpose of getting relatively high bucket-speed. In such a turbine as ordinaily constructed the wheel acted upon directly by the steam or other motive fluid issuing from the nozzle or nozzles develops a materially greater torque than does the second wheel which receives steam only after it has passed through the irst wheel; To overcome this objection and obtain equal or sub'- stantially equal work from each wheel I provide two sets of nozzles, one set delivering directly t-o one wheel and the other set to the opposite, the steam exhausting from one wheel passing through 'and acting on the buckets of the other. If, for any reason the y actual angles of the buckets and nozzles in such a combination have to vary too much I may use intermediate buckets between the wheel-buckets to insure the proper relation. The wheels in such a. turbine have a tendency to revolve at Idifferent and varying speeds, whereas they should either revolve at at the same speed or else one should revolve a certain definite percentage faster than the other. To connect the wheels for such operation electric generators are provided, one driven by each wheel and these are connected electrically in such manner that they preserve the speed relation. l

These generators may furnish alternatingcurrent, and, for example, be of the three- In this event the machines will be interconnected in the proper manner to make them assist each other in feeding the main lines. This constitutes an electrical gearing which takes the place of any mechanical gearing' and holds the turbines at proper speed.

For governing the turbine the yalve-chest Specification of Letters Patent. Application led July 3, 1907.

have invented certain. newl Patented May 1'7,v 1910. Serial No. 381,995. I

with advantage be located on one side of thewheel casing with parts or passa es extending through the casing to the nozz'rles on the opposite side of the wheels as well as to those cn the same side. The valves may be actuated in a variety of ways. As an illustration, I have shown the valves operated by cams through a ratchet and pawl mechanism that moves the cam shaft forward or back in a step-b -step manner under the control of a speed governor mounted on one of the turbine shafts. By preference a valve admitting steam to one wheel will l iirst be opened or closed as the case may be and then one to the other wheel, and so on. Since the wheels are compelled to run at the same speed by reason of the electrical gearingone emergencyV governing mechanism will suiiice for bot-h and the emergency speed governor may advantageously be mounted on the shaftthat does not support the ordinary speed governor. The emergency gov- -ernor is so arranged that when the speed exceeds a certain predetermined `limit it releases a latch and lets a weight or other motor close the main throttle valve of the turbine and thus shut the same down. I

I have referred to wheels having single rows of buckets, ideally simple, but wheels each greater number of rows of buckets employed. In both cases mentioned the velocity of the steam will be abstracted by successive fractions; but in the .latter case the number of operations will be greater, and other things being equal a lower shaft speed may be obtained. l

In thefaccompanying drawings which are .illustrative of one embodiment of my invention, Figure l is a view partly in section of a turbine and two generators driven thereby; Fig. 2 is a plan view of the valve mechanisin with a portion in section; and Fig. 3 is a diagrammatic view of the generator windings.

l indicates rthe bed-plate of the turbogenerator, and mounted thereon are two electric generators 2 and 3 of the alternating-current type, and the casing 4 of the turbine, the latter being connected to a condenser by the conduit 5. Each generator is provided with its own shaft which 1s united to one of the turbine shafts by the coupling 6. Each generator shaft has its aving a may be own bearings carried by the generator cas-v ing, and each turbine shaft has a bearing in the wheel casing with suitable collars 7 to prevent axial movement of the bucketwheels. The generators may be of any well known type and the rotating member may be the field or the armature as best suits the requirements. On each generator is a terminal board 8 carrying binding posts that are connected to its windings and to the conductors 9, 10, and 11 forming a part of the electrical gearing. From these same conductors current is supplied to the outside lines and the translating devices. In certain cases it may be desirable to insert a transformer in these conductors instead of.

making them direct as shown.

Each wheel has a single row of buckets 12 and mechanically is independent of the other. Steam or other elastic motive fluid is admitted to the wheels by a set of nozzles 13 on one side of the turbine and by a set 14 on the other side. These nozzles may be expanding or non-expanding in character as v pawls 22 and 23, one for moving the rockshaft forward, the other for moving it backward. On one of the wheel-shafts is an eccentric surrounded by a strap 24 by means of which and the connecting rod 25 the pawls and the arm carrying them are constantly vibrated. Loosely mounted on the rock-shaft-is a second arm 26 and this carries a shield-plate 27 The arm is connected by rods and bell-crank levers with the speed governor 28 mounted on the generator shaft. The governor changes the position of the shield-plate with changes in load, and said plate controls the action of the pawls on the ratchet-wheel and therefore the position of the rock-shaft, cams and valves.

Steam is admitted to the valve-chest by a throttle valve 29 which can be operated by hand for starting and stopping the turbine or. by a weight under emergency conditions.

`On thespindle of the valve is a drum and wound around the drum is a wire rope or cord 30 having a weight 31 attached to one of its ends. The throttle-valve is normally kept from turning by means of a cord 32 attached at one end to the drum or handwheel at one point and at the other end to a sliding rod 33. 4The end of the cord at- I tached to the hand-wheel is provided with a connector so arranged that the wheel can be set to any desired position by hand to gire any desired opening of the throttle. The rod 33 is held in tension by 'the weight 31 and the collar 311 on the rod engaging a stop 35 on the frame of the generator. Pivotally mounted on the generator is a lever 36 having a fork at the lower end engaging with the collar of a fly-ball emergency gov-.

ernor 37 mounted on the generator shaft. The other end is adapted to engage the rod 33, and release it from the stop 35 when the speed of the turbo-generator becomes abnormally higlnor, if desired, it could be set to trip the valve when the speed becomes abnormally low by proper modification. IVhen the sliding rod is released by being pushed upward the weight 31 overcomes the inertia o f the valve and its attached parts, and closes it.

In Fig. 3 is shown diagrammatically two armatures connected by a three-phase connection to form an electrical gearing be- -tween the two. This connection does not necessarily feed the work circuit as in Fig. 1. In this case the rings 38 and 39 may be taken to indicate `the armatures of directcurrent machines with the commutators and connections omitted. Instead of utilizing either alternating or direct-current machines, I may use one alternating and one direct-current machine with a multiphase connection between, and take off alternatingcurrent single or multiphase at one end of the machine and direct-current at the other.

It will be understood that the different sets of nozzles or the separate nozzle arcs on opposite sides of the pair of wheels are p'eripherally displaced with respect to each other so that there shall be no interference by the f team moving one way with the steam moving from the opposite side. In fact, where the arc lcovered by the nozzles is extended the nozzles on opposite sides of the pair of wheels may be so placed with respect to each other as to be diametrically opposite. If the nozzle are for one wheel should cover an angle of approximately from 120o to 180 this latter disposition would be of course" necessary.

In accordanceP 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 it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure byLetters Patent lof the United States, is,-

1. In an elastic'fluid turbine, the combinal tion of bucket-wheels mounted `to revolve in opposite directions and receive motive Huid one from the other, nozzles arranged on opposite sides of the wheels todischarge iuld through the wheels in opposite directions to las ,equalize the torque thereof, electrical gear- `ing for causing the proper speed relation of the Wheels to be maintained, and a governing mechanism that is common to both Wheels. l v

2. In an elastic fluid turbine, the combination of bucket-Wheels mounted to revolve in opposite directions and receive motive fluid one from the other, nozzles disposed on opposite sides ofthe Wheels and'arranged in sets, a valve-chest, passages extending from the valve-chest to the sets of nozzles, valves for varying the passage of fluid therethrough, and an actuating mechanism common to the valves.

3. Inan elastic fluid turbine, the combination of bucket-Wheels mounted to revolve in opposite `directions and receive motive fluid one 'from the other, nozzles disposed on `opposite y"sides of the Wheel and arranged in sets, a valve-chest, passages extending from the valve-chest to the sets of nozzles,

valves forfvarying the passage of fluid therethrough, an actuating mechanism common to the valves, and electrical gearing for causing-the proper speed-relation of the wheels tobe maintained. v

4; In an elastic Huid turbine, the combination of bucket-Wheels mounted to revolve in opposite directions and receive motive iluid one from the other, nozzles disposed on opposite sides of the Wheel and arranged in sets, a valve-chest located on one side of the Wheels, passages extending from the valvechestto the sets of nozzles, valves for varying the passage .of fluid therethrough, an actuating mechanism common to the valves, electrical gearing for causing the proper speed-relation of the Wheels to be maintained, and a. governor responsive to the speed of the electrically-geared Wheels for shutting oii the supply of motive iuid When the speed becomes abnormal.

In Witnesswhereot', I have hereunto set my hand this 28th day of June 1907.

^ ELII-IU THGMSON, Witnesses JOHN A. McMANUs, Jr., CHARLES A. BARNARD.

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