US803041A - Turbine valve mechanism. - Google Patents

Description

UNrrnn STATES 'Parleur nnrcn.

Specification of Letters Patent.

Patented Oct. 31, 1905.

Application filed April 8, 1905. Serial No. 254,482.

To tt tol/wmf it muy concern:

Beit known that I, JAMES WILKINSON, a citizen of the United States, residing at Birmingham, in the county of J eiferson and State of Alabama. have invented new and useful Improvements in Turbine Valve Mechanism, of which the following is a specification.

My invention relates to controller mechanism for elastic-Huid turbines.

Where turbines have been provided with a plurality of admission-nozzles, it has been found that a more efficient action of the motor iiuid is obtained when a separate valve, designed to have only open and closed positions, is provided for each of the nozzles. The purpose of this is to overcome the objections encountered in the prior practice, where a single valve was adapted to control a number of ports, which objections consisted principally in the wire-drawing action of the valve when partially closing one of the nozzle-ports and in the diiiiculty of operating the valve in the case of turbines of largepower having high initial steam-pressures, so that it would respond relatively to the movement of the governor throughout its travel. The necessity for providing independent motors and valves for each nozzle complicates the controller mechanism and increases the cost of construction. If substantially the same controlling action can be secured by the use of one or more valves, each of which controls a plurality of nozzles, the advantages of such a construction will be obvious. With this object in view I provide an improved valve mechanism illustrative of my present invention adapted to control a plurality of separate nozzles, which will to a large extent avoid the objections encountered in the previous practice above referred to. This mechanism comprises any desired form of valve, preferably a slide-valve and an actuating mechanism therefor, which with a constant initial power is capable of increasing this power as applied to moving the valve over the several ports it controls in a manner to compensate the increasing resistance of the valve as it becomes more and more unbalanced. The actuating mechanism employed in its preferred form consists of a cylinder in which the pressure is varied by the impact action of a fluid-jet under the control of a nozzle and of atoggle-transmission means interposed between the valve and its motor; but inasmuch as the application of a similar fiuidmotor and toggle device for actuating valves adapted to control single nozzles has been shown and claimed in a pending application it is my purpose in this application to secure and protect the advantages derived from such an actuating mechanism when applied to moving a valve over a plurality of ports. A further advantage which is gained by this construction is that the tendency of the valveactuating mechanism will be opposed to holding the valve in wire-drawing positions over any one of the nozzle-ports under its control, for the reason that the valve resistance due to its unbalanced condition and friction is due to equal or slightly exceed the toggle-power at points where more or less of the nozzles are fully closed, whereas when the valve attempts to occupy wire-drawing positions the toggle-power, which increases in a substantially constant ratio, exceeds the valves resistance, which does not increase materially during its movements in opening or closing a port, thus causing the valve to have a tendency to stop between ports and to move back and forth over the critical port with an action similar to the intermittent operation of the critical valve in the case where a plurality of independent governor-controlled valves are utilized.

According to the drawings, in which I have illustrated a preferred form of my invention, Figure l illustrates a partial section through the supply-head of a turbine, showing the nozzles and bucket-wheel in section and the valve and its actuating mechanism in side elevation, the motor and controller device being shown in section. Fig. 2 illustrates the transmission mechanism in a different operating position from that shown in Fig. l. Fig. 3 is a compound chart illustrating by lines and curves the power of the motor, the variable power exerted by the valve-actuating mechanism,

the variable valve resistance, and the combined chart of the several lines and curves.

Similar reference-numerals refer to the same parts throughout.

My invention, which is applicable to any type of multiple-nozzle turbine, is shown applied to an axial-iiow impact-turbine having a supply-head 1 and a bucket-Wheel 2, provided With buckets 3, against which Huid-pressure is discharged through nozzles 4, 5, and 6 formed in a casing 7, secured to the head. The ad mission-ports of the several nozzles are arranged closely together, and their discharge ends are formed in a detachable block 8, also secured to the head and provided with direc- TIO tor-plates 9. The casing 7 is formed with a valve-chest 10, to which theSmo'tor-luidp'ressure is admitted through a port 11. Aslidevalve 12 moves over the several nozzle-ports and is provided with a shoulder 13, to which a valve-stem 14 is connected by nuts 15. The valve-stem 14 projects through one end of the casing, being suitably packed by a gland 16. To the outer end of the stem is pivotally connected a pair of toggle-links 17, which in turn are swivelly connected to a pair oftoggle-levers 18. Links 19 connect the outer ends of the levers to the piston-rod 20. The two 1evers 18 are pivotally mounted upon two {ixed journals 21. If desired, they may be mounted upon the same journal.

The motor for actuating thevalve comprises a cylinder 22, a piston 23, to which the stem 20 is connected, and two passages 24 and 25, leading from opposite ends of the cylinder to acontroller-chamber 26. A controller-nozzle 27 is disposed above the admission ends of the passages 24 and 25 and ac ts to direct the fluid-pressure entering the controller-casing through the port 28 into one or the other, or both, of said passages. The jet of fluid-pressure acts with impact effect to create and maintain pressures at the opposite ends of said cylinder, and by moving the nozzle 27 by means of a lever 29 so that the impact of the jetft'akes more effect in one or the other of said passages pressures ot' different degrees will exist in ends of the cylinder and will unbalance the and `fall.

' described ina pending application.

piston 23, causing the same to be moved by a power equivalent to the dilferential 4between the pressures and through the transmission means to move the valve with an increased power to open or close more or less ofthe nozzle-ports. The controller-Huid pressure is conducted from the controller chamber through port 30, from whence it may be conducted to any desired point of use.

In ydescribing the operation of my invention reference will be made to Fig. 3, in which line a in chart A represents the dierence in the pressure on opposite sides of the `piston 23, which will be provided by the fluid-jet, as directed by the nozzle 'in Fig. 1. The position of the controller-nozzle determines this pressure, which may be raised or lowered on Aeither side of the piston to any desired point. The slight movement of the controller-nozzle, due to the action of the governor responsive to small speed variations, will have atende'ncy to 'cause "the cylinder-pressure to slightly rise Chart B by the line Z2 indicates the curve of the toggle-power applied to move the valve, which power increases 'and aug'ments the m'otors power'as the'angles betweent'he links "19and between the'links v17 and the toggle-levers vanish. 'This action i's more 'fully Chart C vby line .c indicates the valve-resistance-curve, it being noted thattheres'stan'ce 'of th'evalve increases by steps, which is due to the 'fact that its unbalanced condition increases with 'the .number of Eports held closed. Below this chart C is shown the several admission-ports forthe'n'ozzles 4, 5, and 6 to illustrate their relation to the chart. In chart D the lines a,

b, and c are shown combined. The togglepower will rise and fall in correspondencel with variation in the motor-power 'caused by oscillations of the controller-nozzle. These iiuctuations of power represented by the lines a and b are indicated by dotted lines on the chart D. The valve-resistance curve, however, is constant. In considering chart D it will be noted that the resistance of the valve equals the power exerted on it by the toggle only at the points in its travel where it holds one or more of the nozzles closed. Between these points the toggle-power rises considerably in excess of the valves resistance, asindicated by the parting of the lines b and c between the vertical columns e, which correspondin'width with thedivision-walls between the nozzles. Slight fluctuations of pressure producing the change in the position of the toggle-power curve (shown in the dotted lines) will alternately bring this valve resistance above and below the toggle-power, and the valve will be moved slightly back and forth across a division-wall between the nozzles without governing effect. Under these conditionsthe valve will not assume a'wire drawing position. Ii', however, the pressure on one side oi' the piston increases considerably above that on the other side, the valve will be moved across 'a nozzle-port; but by reason oit' the differential between its resistance and its actuating power its tendency while moving over a port will be to oscillate in a manner that will open and close a nozzle rather than Vto assume stationary positions in which it will wiredraw the nozzle. The ycontrollerlnozzle may be used to balance 'the pressure on both sides of the piston, and thus arrest its movement at any point in its travel.

The vto'ggletransmission means are designed to produce an increasing power in proportion to the increase of resistance ofthe valve, which enables the valve to respond with equal accuracy to the `governors regulation at all points in its travel.

The controller-nozzle may be operated by hand or by a governor, and it is my purpose to cover and protect in this application the use oi a plurality of sets of nozzles and valve mechanism therefor, Vpassages being -employed fior conductin the nozzle-controlled ressureto the severa valve-cylinders,which eing of varying dimension will respond successively thereto.

I-I-avin'g thus described vmy invention,what I claim as new, and desire to protect by Letters Patent, is-- l '1. In ja turbine, a rotatable bucket elementfa'plurality ofadmssion-ports discharging lfluidpressure against said element Yto ro- IOO tate it, a valve controlling the low of fluid through said ports, a motor, and a variablepower-transmission means between'said motor and valve.

2. In a turbine, a rotatable bucket element, a group of nozzles, a controller-valve therefor, a power device and a toggle for transmitting motion from said device to said valve to successively cut said nozzles into and out of service.

3. In a turbine, motor-Huid nozzles, a valve for successively cutting said nozzles into and out of service, means for operating said valve comprising a power device and a toggle-transmission means for augmenting the power of said device as applied to moving said valve, substantially proportionately with the increase of the valves resistance.

4. In a turbine, a plurality of nozzles, a valve for successively cutting them out of service, a motor operatively connected to said valve, and fluid pressure -impact controller means for arresting the movement of said motor at any point in its travel.

5. In a turbine, a plurality of nozzles, a valve for successively opening or closing them, a motor comprisingl a cylinder and piston for operating said valve, and a controlling device utilizing the impact action of a fluid-jet to balance said, piston at any point in its travel and unbalance it in either direction.

6. In a controller mechanism for turbines, a cylinder, ports leading from each end there- .of to a fluid-controller chamber, a piston, a

controller-nozzle utilizing the impact action of a luid-jet to control the pressure in each end of said cylinder, a valve moved by said piston, and a plurality of nozzles which are successively opened or closed by said valve.

7. In combination, a fluid-motor, a piston therefor, controller means for the pressure in said cylinder adapted to balance said piston at any point in its travel, a turbine-valve for controllinga plurality of ports, and a toggle connecting said piston and valve, said toggle being designed to increase the power of the motor as applied to said valve, substantially in proportion to the increase of said valves resistance at definite points in its travel.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JAMES WILKINSON. Witnesses:

A. R. FoRsYTH, WM. H. IIURTER.

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