US2678659A - Valve mechanism - Google Patents

Description

y 8, 1954 R. c VAN SICKLE ET AL 2,678,659

VALVE MECHANISM Filed Feb. 7, 1950 Fig.4.

WITNESSES: INVENTORS Roswell C. Van Sickle and Curl G. Lenijes.

I ATTORNE Patented May 18, 1954 VALVE MECHANISM Roswell C. Van Sickle and Carl G. Lentjes, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 7, 1950, Serial No. 142,838

3 Claims.

This invention relates to valve mechanisms in general, and more particularly to valve mechanisms which have a dual function, namely, that of closing at relatively slight pressure and opening at an excessive pressure.

A more specific object is to provide an improved valve mechanism of compact size for a circuit interrupter of the fluid blast type in which the valve mechanism will serve the dual function of being a check valve and also being an overpressure valve.

A further object is to provide a normally open valve mechanism which closes at slight pressure utilizing therefor a relatively slight biasing means and opening at excessive pressure utilizing for the latter function a relatively heavy biasing means. By using two biasing means in the same valve mechanism for the separate functions, the selection of the springs have the desired characteristics is much eaesier.

A further object is to provide an improved dual functioning valve mechanism of compact size in which the selection of a relatively heavy biasing means is made easy by having the excess pressure acting only upon a relatively small portion of the valve.

Further objects and advantages will readily become apparent upon reading the following specification taken in conjunction with the drawings, in which:

, Figure 1 is a side elevational view in vertical section of a circuit interrupter embodying our improved valve mechanism with the tank fragmentarily broken away, the contacts being shown in the closed circuit position;

Fig. .2 is a side elevational view of the lefthand arc-extinguishing unit of Fig. 1, with the top portion in vertical section, the contact structure being shown at an intermediate point in the opening operation, and with the valve parts being in the position resulting from slight pressure; Fig. 3 is a fragmentary view, showing our improved valve mechanism in the position resulting from excessive pressure;

Fig. 4 is a view similar to Fig. 3 but showing the disposition of the several valve parts in the no pressure or static condition, this condition resulting either when the breaker is in the fully closed circuit position or in the fully open circuit position; and 1 Fig. 5 is a top plan view of the movable apertured valve seat of Figs. 2-4.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference numeral I designates a tank filled to the level 2 with a suittil able arc-extinguishing fluid 3, in this instance circuit breaker oil. Depending from the cover 4 of the tank I are a pair of terminal bushings 5, B to the lower ends of which are fixedly secured arc-extinguishing units, generally designated by the reference numeral I.

The two units "I are electrically connected into series circuit by a conducting bridging member 8 reciprocally actuated in a vertical direction by an insulating lift rod 9. The lift or operating rod 9 may be actuated by any suitable mechanism, which forms no part of our invention.

At the opposed extremities of the conducting bridging member 8 are a pair of upstanding rodshaped movable contacts III, which project interiorly within the arc-extinguishing units I, as shown more clearly in Fig. 2, into abutting engagement with intermediate movable contacts II. Suitable biasing means, not shown, biases the intermediate contact II downwardly to its lowermost position, as shown in Fig. 2. There is permitted upward movement from this lowermost position, as shown in Fig. 2, until it strikes a relatively stationary pressure-generating contact I2, the latter being pivotally mounted at I3 and biased downwardly by a compression spring I4 to a lower limiting position as determined by an adjustable stop bolt I5. Preferably, a flexible conducting strap IBis bolted, as at H, to the pressure-generating contact I2 so that the series current need not traverse the pivot pin l3. From the foregoing description, it will be apparent that in the fully closed circuit position of the interrupter, as shown by the full lines in Fig. 1, the lower movable interrupting contact II) has moved upwardly to strike the intermediate contact II carrying the latter upwardly until it strikes the relatively stationary pressure-generating contact I2, the compression spring I4 providing the requisite contact pressure between the several contacts.

During the opening operation, the aforementioned mechanism is responsive either to manual operation or to the existence of overload conditions existing in the controlled circuit to cause downward opening motion of the lift rod 9, the bridging member 8 and the interrupting contacts I0 secured thereto. The downward opening movement of the interrupting contacts I0 permits the intermediate contacts I i to move downwardly therewith for a limited distance, thereby causing a separation between the pressure-generating contacts I2 and the intermediate contacts II to establish pressure-generating arcs I8 therebetween. The pressure-generating are If! is established within a pressure-generating chamber I9 defined by a top dome casting 2c, the latter being bolted, as at 2i, to an adapter 22, the latter being threadedly secured and clamped to the lower end of the terminal stud 23 which passes interiorly through the terminal bushing 5.

Continued downward opening motion of the movable interrupting contact it) causes the intermediate contact H to come to its limiting lower position, as shown in Fig. 2. Further downward opening motion of the movable interrupting contact it causes a separation to occur between the contacts ill, H establishing an interrupting are 24 therebetween. Suitable passage structure provided by the plates iii, not pertinent to our invention, and which is described more fully in United States Patent 2,467,760, issued April 19,, 1949, to Leon R. Ludwig, Benjamin P. Baker and Winthrop M, Leeds, and assigned to the assignee of the instant application, is operative to permit oil under pressure generated at the pressure-- generating arc lit to flow through said passage structure in the direction of the arrows 28 toward the interrupting are 2'! to eilecu the latters extinction. Preferably, the oil after contacting the interrupting arc passes laterally out of the unit l through the vent passages 2?.

t is desirable to provide valve structure which will open upon the attainment of excessive pressure within the unit 7 to prevent possible ruptur ing of the unit. It is also desirable to provide valve structure which will be normally open under no pressure conditions, or under static conditions, so that accumulated gas present from previous interruptions may pass, together with any con-- U taminated oil, out of the unit 7 through such valve structure. The entrance of fresh oil within the unit 5' is desirable and follows from such circulation. However, it is also desirable to have such valve structure close during the existence of relatively low pressure conditions within the unit 1 so that the requisite quantity of oil under pressure may be directed from the pressuregenerating are it toward the interrupting are 24 to effect the latters extinction.

Prior constructions have utilized two separate valves to provide the aforementioned two functions of providing overpressure relief and also the check valve function. However, the use of two separate valves requires considerable space. Furthermore, when a side operating rod construction is utilized to actuate the pressuregenerating contact l2 at the same time as opera tion of the interrupting contact it, as set forth in the aforementioned patent, the space in the wall of the pressure-generating chamber l3, as provided by the casting 253, is at a premium; and it is distinctly desirable to conserve such wall space. In our improved invention, we combine the dual functions within a single valve mechanism, generally designated by the reference character 28.

The valve mechanism 23 comprises a movable apertured valve seat 29, more clearly shown in Fig. 5. The movable valve seat as, as shown in Fig, 5, has a plurality of apertures as provided therein and an upstanding flange portion 3i which is slidably guided by the Walls of a recess 32 formed within the casting it, as shown more clearly in Fig. 2.

The movable valve seat 29 is biased downwardly against a shoulder portion 33 of a stud 34 by a relatively heavy compression spring 3'5. The upper end of the stud 3i has a reduced portion 36, which isthreaded, thereby providing a second Psi 4 shoulder 3'! which engages the top portion 38 of an upstanding recessed portion 39 of the casting 26. Preferably, a nut 40 is threaded upon the threaded reduced portion 36 of the stud 34 to maintain the latter in a fixed position relative to the casting 20.

A movablevalve or valve plate 4| isslidable upon the lower portion 42 of the stud 34. The lower shank portion 42 has a reduced portion 43,

e which is threaded, and threadedly receives a nut 44 which limits the downward sliding travel of the valve plate 4i. Preferably, a relatively light compression spring, is interposed between the top surface of the valve plate 4! and the upper i' end 4t oi a recessed portion 41 integrally formed with the movable apertured valve seat 29.

The operation'of'our improved valve mechanism 28 will now be described. When the interrupter is in the fully closed circuit position, as indicated by the full lines of Fig. 1, or when the interrupter is in the fullyopen circuit position, indicated by the dotted lines 48. of Fig. 1, no pressure exists within the pressure-generating chamber I9, or in other words, staticconditions are present therein, and the valve plate Mr is maintained by gravity and spring 45 at its lower position resting upon the nut 44, as shown more *learly in Fig. 4 of the drawings.

In this static condition of the valve mechanism 28, as shown in Fig. 4; it will be observedthat there is a free venting of accumulatedgases and contaminated oil out of the pressure-generating chamber 59, as indicated by the arrows49 of Fig. 4.

During an opening operation, where relatively light currents are being interrupted, and the pressure generated within the pressure-generating chamber it is relatively slight, it is desirable to conserve this pressure in order to send the requisite quantity of fluid, in this instance oil, under pressure from the pressure-generating are it toward the interrupting are 24. Hence, itis desirable to close the valve mechanism-28 to conserve this pressure, and it will be. apparent that slight pressure within the pressure-generating chamber !9 will act upon the lower surface-of the valve plate 4|, and cause it to move slidably upwardly upon the shankportion 42 of the stud 34 so that it strikes the lower side of the valve seat 29, and closes the apertures 30 provided-in the movable aperturedvalve seat 29', asshown more clearly in Fig. 2.

This upward movement of thevalveplate 41 is opposed. by the downward biasing action exerted by the relatively light compression spring 45.

heavy currents are being interrupted, excessive pressures may be encountered within the pressure-generating chamber l9. It is desirable to vent the pressure generating chamber [9 under these excessive pressure conditions to prevent possible rupturing of the unit 1. It willbe ob served that a small annular area A at the lower end of the movable valveseat29is exposed to th'eexcessive differential pressure up *ahddotvn stream of the movable valve seat (since the valve plate 4! is already in its upward position), and the excessive pressure within the pressure-chamber is acting upon this exposed annular area A will cause the valve seat 29 to move upwardly against the opposition of the relatively heavy compression spring 35, thereby venting the chamber [9 around the periphery of the valve plate 4!, as indicated by the arrows 5! of Fig. 3, shoulder 58 on stud 34 preventing further upward motion of valve plate 4|. Fig. 3, therefore, illustrates the position of the several parts of the valve mechanism 28 during the existence of excessive pressures within the pressure-generating chamber l9, and illustrates how venting under such excessive pressure conditions takes place.

From the foregoing description of the valve mechanism 28, it will be apparent that we have provided a single valve structure, taking no more room than an ordinary valve structure, which is normally open, and which combines the dual functions of serving as a check valve and also as an overpressure valve. Wall space is conserved, which is especially important where a side operating rod construction is utilized. Merely for purposes of simplicity have we illustrated the invention as applied to a circuit interrupter of the sequential break type in which the pressure-generating contact I2 is of relatively simple construction. As mentioned, if the actuating means for the pressure-generating contact i2 is somewhat complicated, by the use of the side operating rod construction, and if the use of an inspection plate is desired, the remaining wall space for the pressure-generating chamber I9 is relatively small, and it is desirable to conserve such space. Accordingly, our improved valve mechanism 28, combining the dual functions within a single valve mechanism, provides a solution for this problem of conserving wall space.

It will be observed that the construction is simple and requires little wall space. The mechanism may be used either generally or in a circuit interrupter of the type shown in Figs. 1 and 2.

Although we have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. A normally-open valve mechanism including a movable apertured valve seat, a valve plate of smaller diameter than the movable valve seat positioned on the presure side of the movable apertured valve seat and spaced therefrom under no pressure conditions, means defining a stop for closing movement of the valve plate in one direction when it has just covered the apertures in the movable apertured valve seat, means biasing the movable valve seat in the opposite direction, means defining a stop for movement of the movable valve seat in said opposite direction, excessive differential pressure up and down stream of the movable valve seat acting only upon the differential area to raise the movable valve seat against the biasing action exerted by said biasing means to relieve the pressure, and the valve plate remaining stationary during such over-pressure movement of the valve seat.

2. A normally-open valve mechanism including 'a movable apertured valve seat, a valve plate of smaller diameter than the movable valve seat positioned on the pressure side of the movable apertured valve seat and spaced therefrom under no pressure conditions, means defining a stop for closing movement of the valve plate in one direction when it has just covered the apertures in the movable apertured valve seat, means biasing the movable valve seat in the opposite direction, means defining a stop for movement of the movable valve seat in said opposite direction, excessive differential pressure up and down stream of the movable valve seat acting only upon the diiferential area to raise the movable valve seat against the biasing action exerted by said biasing means to relieve the pressure, a second relatively light biasing means to bias said valve plate in said opposite direction, and the valve plate remaining stationary during such over-pressure movement of the valve seat.

3. A normally-open valve mechanism including a movable apertured valve seat, a valve plate positioned on the pressure side of the movable apertured valve seat and spaced therefrom under no pressure conditions, means defining a stop for closing movement of the valve plate in one direction when it just closes the apertures in the valve seat and is immediately adjacent thereto, means biasing the movable valve seat in the opposite direction, means defining a stop for movement of the movable valve seat in said opposite direction, a portion of the surface area of the movable apertured valve seat being exposed to excessive pressure to move the movable valve seat in said one direction against the biasing action exerted by said biasing means to relieve the pressure, the first said stop preventing following movement of the valve plate with the movable valve seat under such excessive pressure conditions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 246,858 Aitchison Sept. 13, 1881 1,803,957 Bragg May 5, 1931 2,016,278 Ehlers Oct. 8, 1935 2,299,367 Webb Oct. 20, 1942 2,420,889 Leeds May 20, 1947

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