US2353915A - Throttle valve mechanism - Google Patents

Description

July 1s, 1944.Y

THROTTLE VALVE MECHANISM v'Filed April 25, 1942 l '7 H lNvENToR A171mm H. MEYER.

Y BY

m/,mawMdJ j ATTORNEY F. A. yNn-:YE'R v 2,353,915 'V Patented July 18, 1944 Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,"a,corporation of Pennsylvania Application April 23, 1942, Serial N0. 440,153

6 Claims.

The invention relates to .throttle valves of the general type shown and described in the patent to Schwendner, No. 1,769,968, July 8, 1930, and it has for an object to provide apparatus of this character wherein control is easier because of the change in port area being made relatively less for a given movement, whereby better control of the oil pressure is had and the possibility of accidental tripping by sudden movements of the handwheel is diminished. l0

A further object of the invention is to provide apparatus of the above character which insures of an increased minimum oil pressure under the piston so as to insure of tripping of the valve at partial loadsespecially when it is located below the turbine or prime mover in which case the static head of oil may be equivalent to or almost equivalent to the pressure necessary to sustain the valve.

A further object of the invention is to provide apparatus of the above character wherein tripping of the throttle valve in open position due to surges in oil pressure is greatly minimized. Y

A further object of the invention is to provide a throttle valve operating cylinder with control and tripping valve features, the control valve including a spring which serves to urge the tripping valve into sealing position.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, Vforming a partl of this application, in which:

Fig. l is a fragmentary side elevational ,view

of a turbine showing the control and throttle valve features in section and drawn to larger scale; and

Figs. 2 and 3 are sectional detail views'showing the servo-motor controlling valve.

In the drawing, the turbine or prime mover 9 is supplied with a steam supply conduit I0 which has a throttle valve, at II, the latter being operated by means of the motor device, at I2.` An

impeller I3, or other suitable device, provides oil v46 under pressure supplied through the. orifice I4 to the motor device, at I2. The throttle valve includes a seat I6 with which cooperates the movable valve member II connected to the stem I8 by well-known pressure-balancing means, at I9, 50

facilitating opening of the valve. The stem I8 is connected to the movable element of the motor device, at I2. A pressure relief valve 20 fori the motor device is normally held closed but is opened I The motor device, at I2, includes a housing 2l having an inner 'cylindrical bore 22 containing the 'operating piston 23. Thev operating piston has a stem structure 24 attached by suitable coupling means 25 to the stem I8. Thus, the throttle valve is opened and closed by upward and downward movement of the piston 23.

Within the housing, there is disposed a spring 26 acting on the piston 23 to move the throttle valve in `a closing direction. The piston is 'moved against the force of the spring 26 by means of oil pressure admittedto the pressure space 28 at the side of the'piston opposite to the spring space 29, oil under pressure being supplied to the pressure space by meansof the orifice I4. It will be apparent, therefore, that; if the pressure in the space 28 is suddenly relieved, the rate of supply of oil thereto being limited by the orice I4, the spring 26 will be effective to move the piston and the throttle valvein a closing direction.

The piston 23 is formed with a passage 3l) which connects the space 28 withthe central opening 3I formed in the piston and whose discharge or upper end 32 is arranged to communicate with the spring space, the latter being provided with an oil drain or overflow opening 33. The discharge end 32 of the central opening is provided by means of a flat plate 34 having a flat seat 35 with which the cup valvev 36y cooperates. As long'as the annular lip of the cup valve 36 is in sealing engagementl with the at surface 35, then pressure of oil builds up underneath the piston 23 `to move the latter upwardly or in a direction to open the throttle valve. On the otherhand, if the cup valve 36 moves away from the seat, then the pressure of oil in the space 28 is suddenly released and the spring 25 closes the throttle valve.

The cup valve 36 has a sleeve portion 31 slidable on o r telescopically arranged with respect to the sleeve member 33.V TheA sleeve member has a central bore 39 which telescopically receives the lower end yof the stem 40. `A channel 4I vis formedin the sleeve member and extends longitudinally thereof, the upper end of the channel being in continuous communication with the spring space 29 andy its lower end 42 being arranged to be lapped by the slide valveelement 43 of the sleeve portion 31. A spring 44 encompasses the sleeve portion 31 and the sleeve member 38, the-upper end of the spring abutting the collar 45 and the lower end engaging the upper surface 45 of the cup valve 36 so as to exert force on the cup valve tending to move the latter into by the emergency or overspeed trip device, at 20a. A|55 sealing engagementl with the seating surface 35.

the threaded portion 50, the stem has a portion.

52 engageable with a handwheel 53 so that the stem may be turned. K

Assuming that the slide valve element 43 of the sleeve portion 31 laps the lower end42 of the channel 4|, then upward movement of the stem is followed by upward movement of the piston due to the pressure of oil acting therebelow. With the piston sustained by oil pressure, if the stem 40 is moved downwardly, then the sleeve` portion 38 moves with it to place the channel 4| in communication with the pressure space, wherelby oil will be by-passed from the pressure space and the spring will be effective to move the piston downwardly, such downward movement of the piston tending, because of the spring 44, to bring about the lapping condition of the slide valve portion 43 with respect to the lower end 42 of the channel. Thus, it will be seen that upward and downward movements of the stem 40 are accompanied by following movements of the piston 23, the piston being moved by the spring 26 in a closing direction, when pressure in the pressure space is relieved, and being moved in an opening direction upon upward movement on account of pressure building up in the pressure space due to restriction of escape through the channel 4| The housing 2| carries an adjustable sleeve 55 whose lower end cooperates with the seat 35 to limit upward or opening movement of the piston. The sleeve 55 is so adjusted that the lower end thereof is spaced from the seat 35, when the throttle valve is in closed position, such that, in relation to the spacing'of the stop collar 56 on the stem 40 from the nut 5|, with opening movement of the piston limited by the sleeve, continued upward movement of the screw 50 until its collar 56 engages the lower end of the nut 5| assures that, due to the spring 44, the sleeve valve portion 43 shall lap the lower end of the passage 42 by a slight amount, for example le of an inch (see Fig. 3). n

With the seat l35 spaced from the sleeveV 55 as just stated, it will be apparent that, with downward movement of the throttle valve element I8 then, with the cup valve 36 engaging the seat 35 the stem may be moved down further to move the sleeve member 38 downwardly relatively to the sleeve portion 31 to open the lower end of the channel 4|. As shown, the sleeve member 38 has an abutment 58 which is normally spaced a slight distance from the piston surface 59, for example, M3 of an inch. Thus, it is assured that with the piston 23 in its lowermost position and the abutment 58 engaging the piston surface 59, the lower` end of the channel 4| will be opened Re of an inch (see Fig. 2). In this'way, so long as the throttle valve is held in closed position by means of the stem, it is impossible, because of relief affordedj by the by-passing open channel 4|, for pressure to build up underneath the piston.

With the piston 23 in the throttle closing position, as shown, and with the stem 40 holding the abutment 58 in contact with the surface 59,

engaging thel seat |1.

piston 23 limited by the the first effect of upward movement of the stem is to cause the sleeve member 38 to follow it, the force of the spring 44 being effective for this purpose; and, just as soon as the valve portion 43 laps the lower edge 42 of the channel, then pressure of oil acting below the piston causes the latter Vto move upwardly.. Upward movement of thewpiston 'will continue so long as the screw is moved upwardly. If the screw is moved upwardvly only for a fraction of its stroke, then the position of the piston is determined by opposing forces of the spring 26 and of pressure of oil in the pressure space 28, upward movement of the piston opening the port area of communication of the channel 4| with the pressure space to bring about equlilibrium of fluid pressure and spring forces. i

In the event of sudden drop of pressure 1n the 4pressure spa-ce 28, due, for example, to operation of the overspeed trip device, the piston 23 is moved downwardly by the spring 26, and, as soon as its seat 35 leaves the cup valve 36, copious discharge area for oil is thereby provided with the result that the throttle valve is quickly closed by the spring.

While the invention has been shown` in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall vbe placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. Means for actuatingva throttle valve for a prime mover in response to an operating characteristic of the latter and comprising a cylinder, a piston in the cylinder, said piston dividing'the interior of the cylinder into a drainage space and a pressure space, av first spring exerting force on the piston, means including an orifice for Supply ing liquid from a suitable source to the pressure space to exert force on the piston in opposition to that of said spring, means for effecting sud# den release of lpressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston, means including a nut for supporting the stem from the cylinder, said 'pis'J ton having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space, a valve in covering relation with respect to the discharge end of the opening and cooperating with the piston to interrupt ow through the latter, a niember abutting theinner end of the stem, a second yspring between said member and the valve, a by# pass passage formed in the abutmentv member Vand continuously open to the drainage space of the cylinder, a valve portion carried by said valve and slidable with respect to the memberto overlap. the inner end of the passage to interrupt vcommunication thereof with the pressure chamber and to uncover the inner end of the passage vto provide for communication thereof with the pressure chamber, said slide valve portion cooperating with the inner end of the passage to provide an area of communication thereof with the pressure space which gradually increases or decreases with relative opening and closing movements of the slide valve portion and of the abutment member from and toward lapping position, and means for turning the stem.

2. Means for actuating a throttle valveY for a -prime mover in response to an operating char;

acteristic of the latter and comprising a cylinder; a piston in the cylinder; said piston dividing the interior of the cylinder into a drainage space and a pressure space; a iirstY spring exerting force on the piston; means including an orifice for supplying liquid from a suitable source to the pressure space to exert force on the piston in opposition to that of said spring; means for effecting sudden release of pressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston; means including a nut for supporting the stem from the cylinder; said piston having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space; Va valve in covering relation with respect to the discharge end of the openingr and cooperating with the piston to interrupt flow through the latter; a member abutting the inner end of the stem; a second'spring between said member and the valve; a by-pass channel formed in the abutment member and continuously open to the drainage space of the cylinder; a Valve portion carried by said valve and slidable with respect to the member to overlap the inner end of the channel to interrupt communication thereof with the pressure chamber and to uncover the inner end of the passage to provide for communication thereof with the pressure chamber; said slide valve portion cooperating with the inner end of the passage to provide an area of communication thereof with the pressure space which gradually increases or decreases with opening and closing of the slide valve and of the abutment member from and toward lapping position; a stop carried by the cylinder and adapted to contact with the piston to limit outward movement thereof; a stop carried by the screw for limiting its outward movement; means providing for location of the stop carried by the cylinder such that, With the outward position of the piston limited thereby and with outward movement of the screw limited by its stop, said slide valve portion will lap the inner end of the bypass passage; means for limiting continued inward movement of the screw after stopping of the piston due to seating the throttle valve in closed position so that the slide valve portion uncovers the inner end of the passage to place the latter in communication with the pressure space; and means for turning the stem.

3. Means for actuating a throttle valve for a prime mover in response to an operating characteristic of the latter and comprising a cylinder; a piston in the cylinder; said piston dividing the interior of the cylinder into a drainage space and a pressure space; a first spring exerting force on the piston; means including an orifice for supplying liquid from a suitable source to the pressure space to exert force on the piston in opposition to that of said spring; means for a effecting sudden release of pressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston; means including a nut for supporting the stem from the cylinder; said piston having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space; a sleeve member telescoping the inner end portion of the stem and closed at its inner end to abut the inner end of the stem; a valve member carried by the sleeve member and slidable longitudinally of the latter; said sleeve member having a passage continuously open t said drain space;l said valve member including Aacup valve portion and a slide valve portion; the cup valve portion cooperating with the piston to interrupt flowv through `the opening of the latter from thepressure space to the drain space and the slide valve portion cooperating with the sleeve member to lap the inner end of said passage to interrupt communication of the latter with the pressure space or to provide a variable area of communication therewith dependent upon relative movement of the sleeve and valve members; a second spring carried by the sleeve member and acting on the'valve member to urge the latter to move toward said piston; and means for turning the stern. f l

4. Means for actuating a throttle valve for a prime mover in response to an operating'V characteristic of the latter and comprising a cylinder; a piston in the cylinder; said piston dividing the interior of the cylinder into a drainage space and a pressure space; a rst spring exerting force on the piston; meansnincluding an orice for supplying liquid from a suitable source tothe pressure space to exert force on the piston in opposition to that of said spring; means for effecting sudden release of pressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston; means including a nut for supporting the stem from the cylinder; said piston having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space; a sleeve member telescoping the inner end portion of the stem and closed at its inner end to abut the inner end of the stem; a valve member carried bythe sleeve member and movable longitudinally of the latter; said sleeve member having a passage continuously open to said drain space; said valve member including a cup valve portion and a slide valve portion; the cup valve portion cooperating with the piston to interrupt flow through the opening of the latter from'the pressure space to the drain space andthe slide valve portion cooperating with the sleeve member to lap the inner end of said passage to interrupt communication of the latter with the pressure space or to provide a variable area of communication therewith dependent upon relative movement of the sleeve and valve members; a second spring carried by the sleeve member and acting on the valve member to urge the latter to move toward said piston; a stop carried by the cylinder and adapted to contact with the piston to limit outward movement thereof; a stop carried by the screw for limiting outward movement thereof; means providing for location of the stop carried by the cylinder such that, with the outward position of the piston limited thereby and with outward movement of the screw limited by its stop, the slide valve portion will lap the inner end of the passage; means for limiting continued inward movement of the screw after stopping of the piston so that the slide valve portion uncovers the inner end of the passage to place the latter in communication with the pressure space; and means for turning the stem.

5. Means for actuating a throttle valve for a prime mover in response to an operating characteristic of the latter and comprising a cylinder; a piston in the cylinder; said piston dividing the interior of the cylinder into a drainage space and a pressure space; a iirst spring exerting force on the piston; means including an orifice for supplying liquid from a suitable source to the pressure space to exert force on the piston in opposition to that of said spring; means for effecting sudden release of pressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston; means including a nut for supporting the stem from the cylinder; said piston having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space; a sleeve member telescoping the inner end portion of the s-tem and having its inner end closed to abut the inner end of the stem; a valve member carried by the sleeve member and movable longitudinally of the latter; said sleeve member havving a channel open to its outer surface and extending longitudinally thereof; said valve member including a cup valve portion and a sleeve valve portion; said cup valve portion cooperating with the piston to ,interrupt flow through the opening of the latter from the pressure space to the drain space and said sleeve valve portion being slidably mounted on the sleeve member and cooperating with the latter to lap the inner end of said channel to interrupt communication thereof with the pressure space or to provide a variable area of communication thereof with the latter dependent upon relative movement of the sleeve and valve members; a second spring carried by the sleeve member and acting on the valve member to urge the latter to move toward said piston; means carried by the sleeve member to retain the valve member thereon when the cup valve portion is separated from the piston; and means for turning the stem.

6. Means for actuating a throttle valve for a prime mover in response to an operating characteristic of the latter and comprising a cylinder; a piston in the cylinder; said piston dividing the interior of the cylinder into a drainage space and a pressure space; a first spring exerting force on the piston; means including an orifice for supplying liquid from a suitable source to the pressure space to exert force on the piston in opposition to that of said spring; means for effecting sudden release of pressure in said pressure space; a threaded stem having its inner end disposed adjacent to the piston; means including a nut for supporting the stem from the cylinder; said piston having an opening extending therethrough and providing for discharge of liquid from the pressure space to the drainage space; a sleeve member telescoping the inner end portion of the stem and closed at its inner end to abut the inner end of the stem; said sleeve member having spaced inner and outer collars; a valve member carried by the sleeve member and movable longitudinally between the collars of the latter; said sleeve member having a channel open to the exterior thereof and continuously open to said drain space; said inner collar being spaced inwardly from the inner end of the channel; said valve member including a cup valve portion and a sleeve valve portion slidable on the sleeve member; the cup valve portion cooperating with the piston to interrupt ilow through the opening of the latter from the pressure space to the drain space and said sleeve valve portion cooperating with the sleeve member to lap the inner end of said channel to interrupt communication of the latter with a pressure space or to provide a variable area of communication with the latter dependent upon relative movement of the sleeve and valve members; a second spring between the outer collar and the valve member for exerting force on the latter; a stop carried by the cylinder and adapted to contact with the piston to limit opening movement thereof; a stop carried by the stem for limiting outward movement; thereof; means providing for location of the stop of the cylinder Such that, with the outward position of the piston limited thereby and with outward movement of the screw limited by its stop, the sleeve valve portion will lap the inner end of the channel; means for limiting continued inward movement of the screw after stopping of the piston so that the sleeve valve portion uncovers the inner end of the channel to place the latter in communication with the pressure space; and means for turning the stem.

FRANK A. MEYER.

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