US1608565A

US1608565A - Controlling device for jet-impelled water turbines

Info

Publication number: US1608565A
Application number: US135669A
Authority: US
Inventors: Pitman Percy Hector
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-04-07
Filing date: 1926-09-15
Publication date: 1926-11-30
Anticipated expiration: 1943-11-30

Description

Nov. 30 1926. V 1,608,565

P. H. PITMAN GON'I'ROIQDING DEVICE FOR JET IMPELLED WATER TURBINES Filed Sept. 15. 1926 2 Sheets-Sheet l i P z cq 4 2 1R1 .1.5.4 a j z I 1 WW7? Nov. 30 19 6. I 1,608,565

P. H. PITMAN CONTROLLING DEVICE FOR JET IMPELLEP WATER TURBINES Filed Sept. 15 1926 2 Sheets-Sheet 2 Patented Nov. 30, 1926.

ED STATES OFF [C E.

PERCY HECTOR IITMAN, OF LONDON, ENGLAND;

CONTROLLING DEVICE FOR JET-IMiBELLED WATER TURBINES.

Application filedseptember 15, 1926, Serial No. 135,669, and in Great Britain April 7, 1925.

This invention relates to the controlling devices of impulse turbines of the Pelton wheel type ofthe kind provided with a jet deflector and has for its object improvements in the" construction thereof whereby the same can be operated with a minimum of power and efficient governing can be obtained.

Controlling devices of the kind referred to, as heretofore constructed, have employed a deflector consisting of an inclined plate carriedby pivotedarms connected to a governor by which the said plate was caused to enter the jetso as to divert a suitable proportion of the water from the blades of the turbinewhile the supply was being gradual- 1y curtailed in order to maintain the desired speed under different conditions of load;

Owing to the resistance to be overcome when. a deflector of the kind referred to is inserted into a high pressure jet considerable energy was required to actuate it and this necessitatedin the case of large units the employment of auxiliary apparatus which delayed its controlling action and rendered the governing less sensitive and ineflicient.

In order to overcome the foregoing difficulties'the present invention comprises a balanced deflector that is acted upon by the jet at two points in such a way as to tend to turn. it in opposite directions about its point of support. As the forces applied at these points are substantially equal they balance each other with the result that a minimum effort is required to turn the improved deflector.

In some cases the improvedwdeflector is coupled to a needle valve that controls the diameter of thewater jet. For this purpose the needle or spearisiprovided withmeans of :retarding: its movement in the direction to out oft 'thewater supply (so. as to avoid nalledon v trunnion bearings. is supported coaxially with the jet, which, when the turbine is running. with a full load passes centrally through the bore of the deflector.

When the deflector is turned in its bearings 'oneside of its outer surface at the end nearest the nozzle and the other side ofits inner surface at its opposite end are brought into contact with the jet so as to deflect more or less of the water. away from the buckets of the turbine according to the angle through which the deflector is turned. The contour ofthe inner and outer surfaces of the deflectors are of such configuration that the tendency of the jet to turn the deflector inrone direction by reason of its impinging against one end is counteracted by thetendency to turn it in the opposite direction by reason of the impingement ofthe said jet against the opposite end of the deflector.

The deflector may be operated by a hand lever mounted on or connected to one of its trunnions by suitable linkage or it may be operated by a hand wheel or a governor suitably connected to an arm secured to the deflector, This linkage may also impart longitudinal movement to the spear of a jet-controlling valve through a spring.

In order to prevent the too-rapid closing of the valve the spear is provided with a dash-pot or oil cylinder and has two shoul ders between which is situated a sleeve con nectedto a lever, hand wheel or governor through the aforesaid linkage. A spring is situated between the forward end of the sleeve andthe shoulder on that side so that when the linkage is operated in the direction to close the valve the spring will be compressed and will slowly urge the spear forward at a speed controlled by the dashp Then the movement'is in the opposite direction the sleeve will directly engage the rear shoulder and immediately withdraw the spear to the extent determined by its operating means.

I will now describe my invention more particularly with the aid ofthe accompanying. diagrammatic drawings in which *ig. 1' shows in vertical section one embodimentof the improved deflector and controlling gear in the-full load position, as applied to a Pelton wheel,

Fig. 2 is a similar view showing the parts in theirrespective positions after the load has beenremoved,

Fig. 3 is a-detail showing a similar view able device,

of the deflector in the position it takes up after the jet has been reduced by the controlling valve to suit the reduced load,

Fig. 4 is a'plan view of the deflector and jet nozzle and Fig. 5 is a front view of the defiectorwhen in the full load position. 7

According to the construction shown in the drawings a represents the buckets of a Pelton wheel and c the nozzle'by which a jet d of high pressure water is directed on to the said buckets so as to rotate the wheel and drive the turbine.

When the load is reduced the speed of the motor will increase unless the rod 6 be moved in thedirection ot the arrow in ,Fig. 1 so as to in ve the parts towards the position shown in Fig. 2.

The rod 6 may be operated by a lever, iand wheel or any suitable governor through suitable linkage as hereinbetore statec.

The deflector f is of tubular form and is provided with trunnions g journalled in bearings it (Big. l) formed integrally with or bolted to the nozzle 0, When the said defiector is turned onits truiinions in the direction indicated in Fig. 1 its inner surface 2' at its forward end will deflect the jet d in a downwarddirection away from the bucket-s a, and the rear edge 7' of the deflector will cut into the said jet and so divide it into two parts at and (Z v Darius this process the pressure of the jet (Z on the surface 2' will tend to turn the deflector in a countercloclm'ise direction'and the pressure of the jet (5 on the under sur face is or the said deflector which will tend to turn it iii a oloclzwise direction with an equal force that will counteract the effect oi the jet (Z on thesuriace 2 thus enabling the deflector to be actuated with a minimum 7 amount of energy.

in order to obtain a steady action of deflector the end or" the surfaces and edge j should not be too far from the point about which the deflector turns and so as to the produce the necessary compensating lift at 3' V ;to slide on the spear-rod which is provided with two shouiders s tend a springer. The spear rod has a head a at one end that co-operates with the aperture to in the nozzle 0 to regulate thean iount of water delivered .by

the jet and is guided by a bearing andp'asses out of the conduit y through the labyrinth packing a, a -glan-d or any othersuit the The opposite extremity of the spear-rod 1" is connected to the plungerl of an oil cylinder whose opposite ends are connected by a pipe 3 provided with a valve 4: to regulate the speed at which the oil can be transferred from the front end of the cylinder to the 7 rear. The plunger i is provided with one or more valves 5 which allows the oil to pass freely through them from the back to the front of the cylinder when the spear-head v is moved in the direction to increase the area of the aperture 10. The deflector f is provided with a stop 7 that engages a projection 7 formed on an adjacent part when the turbine is running with full load.

in operation the slee e is moved in the of the cyl nder whi h may be adjusted by the valve 2;

So se-on the speed of the turbine has been induced by the smaller quantity of water deliverec to the buckets by the nozzle 0 V the rod 6 will be moved automatically if a governor is employed or by hand, in therever a position in which the reduced et just escapes he edge of the surface 2' and the edge of the deflector; This movement will result in a read ustment the jet controllin valve until a position is reached in which the aforesaid reiationsl ip is maintained. When the sleevey is moved in' a rearward direction owing to an increase in the load, such movement is transmitted "directly through the shoulder 8 to the spearrod1j whose operation in hat direction is not re tarded by the oil in the cylinder2. fl claim: 7 f jj r 1. An improved. controlling device for impulse turbines comprising balanced tu bular jet defiector'supported in bearings and formed on opposite sides of its bore and of the axis of said bearing with deflecting se direction until the deflector f assumes direction to compress the spring'a when L-HE cylinder .Zcan be trans-1 ferred' through the pipe 3 to the rear end portions, said deflecting portions "being;

formed with cooperating surfaces to be operated upon bythe deflected portions of said et, so that such action on one said deflecting portion will counterbalance the action on the other said deflecting portion. H I

2. An improved controlling device for impulse turbines comprisinga balanced tu hula-r deflector throughthe bore of" the power etinormally passes coaxially,

transverse bearings to support said defleotor, said deflector having two intercepting portions situated on opposite sides o'f' flthe bore of said defiectorandon oppositesides of the axis of said bearing and moved into and out of said jet according to the direction and degree of movement of said deflector in its bearing, said intercepting portions having surfaces against which the deflected portions of said jet impinge so as to tend to turn the deflector in reverse directions and means of gradually inserting both intercepting portions into said jet at the same time to deflect a portion of said jet away from the turbine buckets and to balance the turning moments produced by the jet impinging on the intercepting portions of the. deflector substantially as set forth.

3. An improved controlling device for impulse turbines comprising a balanced tubular deflector through the bore of which the power jet normally passes coaxially, transverse hearings to support said deflector, said deflector having two intercepting portions situated on opposite sides of the bore of said deflector and on opposite sides of the. axis of said bearing and moved into and out of said jet according to the direction and degree of movement of said deflector in its bearing, said intercepting portions having surfaces against which the deflected portions of said jet impinge so as to tend to turn the deflector in reverse directions, means of gradually inserting both intercepting portions into said jet at the. same time to deflect a portion of said jet away from the turbine buckets and to balance the turning moments produced by the jet impinging on the intercepting portions of the deflector, a. jet controlling valve, a valve rod having two fiXGCl shoulders thereon, a sliding collar between said shoulders, a spring between said collar and the forward shoulder, a lever connected to said collar, a rod connected to said lever and to the deflector actuating means and means of operating said rod, substantially as set forth.

4. An improved controlling device for impulse turbines comprising a balanced tubular deflector through the bore of which the power jet normally passes coaxially, transverse hearings to support said deflector, said deflector having two intercepting portions situated on opposite sides of the bore of said deflector and on opposite sides of the axis of said bearing and moved int-o and out of said jet according to the direction and degree of movement of said defiector in its bearing, said intercepting portions having surfaces against which the deflected portions of said jet impinge so as to tend to turn the deflector in reverse directions, means of gradually inserting both intercepting portions into said jet at the same time to deflect a portion of said jet away from the-turbine. buckets and to balance the turning moments produced by the jet impinging on the intercepting portions of the deflector, a. jet controlling valve, a valve rod, a conical head at one end of said valve rod, a plunger connected to said rod, a cylinder in which said plunger is adapted to slide, fluid in said cylinder, a valve in said plunger to permit said fluid to pass in one direction, a channel to allow said fluid to pass from one end of said cylinder to the other in the opposite direction, a valve in said channel to adjust the speed at which said fluid passes, two fixed shoulders on said valve rod, a sliding collar between said shoulders, a spring between said collar and the forward shoulder, a lever connected to said collar, a rod connected to said lever and to the deflector actuating means and means of operating said rod, substantially as set forth.

In testimonyrwhereof, I have signed my name to this specification at 61 and 62 Chancery Lane, in the county of London, England, this 3rd day of September, 1926.

PERCY HECTOR PITMAN.