US2288472A - Circuit interrupter - Google Patents

Description

June 30, 1942. J.B. MacNElLL ETAL CIRCUIT INTERRUPTER Filed Sept. 21, 1940 2 Sheets-Sheet l INVENTORS John B MaeNeill and WITNESSE1 401% Andrew H. Baldren.

BY vz/ ATTORITQEY June 30, 19 2. J. B. M NElLL ET AL ,4

CIRCUIT INTERRUPTER WITNESSES:

A RN

Patented June 30, 1942 2,288,472 CIRCUIT INTERRUPTER John B. MacNeill, Wilkinsburg, and Andrew H.

Bakken, Edgewood, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 21, 1940, Serial No. 357,674

8 Claims.

This invention relates to improvements in circuit interrupters, and more particularly to structure for controlling and conducting the flow of an arc extinguishing blast of gas in circuit interrupters of the gas blast type. In circuit interrupters utilizing a compressed gas, such as air, to extinguish the arc, it is desirable to provide an individual gas storage tank or reservoir for each breaker unit. A general arrangement of parts that has been found satisfactory is illustrated in A. H. Bakken application Serial No. 313,745, filed January 13, 1940, and assigned to the assignee of the instant application. In accordance with the aforesaid Bakken application, the gas storage tank is maintained at ground potential and basically constitutes a support for the contact structure, are extinguisher, and operating mechanism. The contacts and arc extinguisher must necessarily be insulated from the tank and are, therefore, preferably supported by insulating members carried by the tank. The conduit means for conducting the arc extinguished blast of gas to the arc extinguisher must contain sufiicient insulation to prevent flash-over from the contact structureto ground. In order to maintain as many of the mechanical moving parts as possible at ground potential, the gas blast valve is preferably located adjacent the gas storage tank.

Applicants have discovered that although the general arrangement of parts shown in the aforesaid application is desirable, the specific arrangement can be improved to provide for easier servicing of several of the separate parts constituting the interrupter without any considerable dismantling of the entire breaker structure.

The main object of the instant invention is to provide a compressed gas blast circuit interrupter, the various parts of which are so arranged so as to permit ready removal and replacement thereof without unduly disturbing the position of adjacent parts.

A more specific object of the invention resides in the provision of a gas storage tank for gas blast circuit breakers and conduit means for controlling and conducting a blast of pressure gas to the arc extinguisher from the tank so arranged that the blast control valve of the conduit means can be removed and replaced without disturbing the arc extinguisher or the contact structure, and likewise that the tank itself may also be removed without disturbing the arc extinguisher and the contact structure.

A furthehr object of the invention resides in the provision of gas blast conducting means including a gas blast valve for conducting and controlling a blast of arc extinguishing gas to the arc extinguisher of a circuit breaker so arranged that the gas under pressure in the breaker storage tank is used with maximum effectiveness. For example, this may be accomplished by providing a straight conducting gas blast passage from the storage tank through the valve housing to the arc extinguishing structure, and further, by shaping the valve so as to reduce turbulence in the valve housing to a minimum.

Other objects and advantages will appear in the following description when considered in connection with the accompanying drawings, in which;

Fig. 1 is a side elevational view partly in section of a circuit interrupter constructed in accordance with our invention.

Fig. 2 is a fragmentary sectional view on an enlarged scale illustrating the valve housing, valve, and the conduit coupling, and,

Fig. 3 is a plan view of valve housing and valve shown in Fig. 2, the conduit and coupling having been omitted to more clearly show the valve construction.

Referring to the drawings, the reference numeral I designates a framework for supporting the several elements of the breaker. Rising from the upper portion of the framework I are two insulating supports 3, only one of which is shown. The upper ends of the supports 3 carry an arc extinguishing structure 5, the lower portion only of which is illustrated. The are extinguisher 5 is further supported by a tubular conduit and insulator I, the lower end of which extends through a suitable opening in a channel member 9 carried by the upper cross members of the frame I. 1 may be provided at its lower end with a split ring II having an inwardly extending flange which projects into a suitable circumferential groove in the insulating member. A ring I3 of wedge-shaped cross section is adapted to encircle the split ring II and is bolted to the channel member 9 so as to clamp the ring ll tightly to the tubular support 1 and at the same time secure it to the channel 9.

The are extinguisher 5 houses the breaker contact structure comprising a stationary contact assembly I5 and a coacting movable contact ll of blade form and generally of C-sha,.e. The movable contact ll is hinged at I9 to a conducting bracket 2| which, in this instance, may be supported by the tubular insulator I and the insulating support members 3. The stationary contact assembly [5 has a line terminal connector More specifically, the tubular support 23 for making external connection to the breaker, whereas the conducting bracket -2| is provided with a similar connector 25 for the same purpose. Thus, when the breaker contacts are in the closed-circuit position, the circuit through the interrupter proceeds from the terminal 23 to the stationary contact assembly I5, the movable contact H, the conducting bracket 2|, and terminates at the terminal 25.

The movable contact I! is actuated to the open and closed circuit positions by an insulating operating rod 21 actuated by a bell crank 29 pivoted on the framefitifl, which is in turn actuated by a compressed air operated mechanism generally indicated at 3|. The operating mechanism 3| is actuated by gas under pressure such as air stored in a reservoir or tank 33 mounted upon the lower cross members 01' the framework I. Inasmuch as the specific form of operating mechanism is not peculiar to this invention, it will sufiice to say that the mechanism 3| includes suitable control valves for admitting air under pressure from the tank 33 to an air cylinder having a piston therein to efiect the opening and closing movement of the contact |'l.

During the opening operation of the interrupter under load, anarc is drawn between the contacts I and I1 across the discharge end 35 of the tubular insulator I. The tubular insulator I, in addition to serving as a support for the arc extinguisher 5, also serves as a conduit to direct a blast of arc extinguishing gas under pressure from the storage tank 33 upon the are playing in the extinguisher 5. The are extinguishing blast from the tank 33 is controlled by a valve having a valve head 31 disposed within a valve housing 39 secured by bolts 42 to a short flanged outlet conduit 4| extending from the tank 33. The valve housing 39 has a through passage 43 therein in axial alignment with the short outlet conduit 4|. The valve head 31 is adapted to seat against the lower side of the housing 39 and seals the passage 43. A suitable gasket 44 between the housing 39 and the outlet conduit 4| provides an air-tight seal for maintaining the pressure within the tank 33 between interrupter operations.

The upper end of the passage 43 is threaded and is adapted to receive a threaded sleeve 45 which, when screwed outwardly with respect to the housing 39, will be brought into abutting engagement with the lower end of the conduit 1. In order to facilitate rotation of the sleeve 45, the portions thereof above the threads may be provided with projections 45 or may have any other configuration which provides a convenient gripping surface for a wrench. The tubular sleeve 45 has an inside diameter substantially the same as the inside diameter of the tubular supporting conduit I and is in axial alignment with the passage in the tubular conduit 1. Inasmuch as the blast of air to extinguish the arc flows through the tubular member I only a very short time, the abutting engagement of the threaded sleeve 45 with the lower end of the tubular insulator 1 provides an adequate seal against the loss of compressed gas.

Operation of the valve head 31 for controlling the blast of air may be accomplished by a rocker arm 41 secured to a cross shaft 49 journalled in the valve housing 39. The portion of the rocker arm extending outside the valve housing 39 is provided with a roller 5| adapted to engage a cam 53, in this instance, forming a part of the bell crank 29 for actuating the contact H to the open and closed positions. A spring 55, operative between the rocker arm 41 and a suitable bracket 51 carried by the valve housing 39, normally maintains the valve in the closed position. It will thus be seen that as the moving contact I1 is actuated to the open-circuit position by the operating mechanism 3|, the bell crank 29 and also the cam 53 will be rotated in a counterclockwise direction so that the cam 53 engages the roller 5| whereby the rocker arm 41 is rotated in a counter-clockwise direction against the tension 01 the spring '55 to open the valve. It will be noted that since the short outlet conduit 4|, the passage 43 in the valve housing 39, the adjustable sleeve 45, and the tubular support I are all in alignment, a straight and direct passage for the arc extinguishing blast is provided. In order to further prevent the loss of pressure due to turbulence or air flowing from the tank 33 to the tubular support I, the valve head 31 is made of conical form and is provided with a plurality of, preferably 3, radially extending ribs 59 which extend outwardly to engage the wall defining the passage 43 so as to maintain the valve head 31 in alignment within the passage during its movement to the open and closed positions.

From the foregoing description, it will be ap-' parent that in the event it becomes necessary to inspect or repair the valve mechanism which controls the blast of air during interruption, it merely becomes necessary to screw the threaded sleeve 45 downwardly away from the lower end of the tubular insulator I and remove the bolts 42 which clamp the valve housing 39 tothe flanged outlet conduit 4|. The valve housing 39, including the valve head 31 and its operating mechanism, may then be removed without disturbing the interrupter contacts or the are extinguishing structure.

It will also be seen that the foregoing arrangement permits the storage tank 33 to be removed for inspection or repair without disturbing the interrupter contacts or the arc extinguishing structure.

Although wehave shown a specific circuit interrupter, it is to be understood that the same is for the purpose oi! illustration and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a gas blast circuit interrupter, as storage tank, separable contact means insulatingly said contact means, said gas conducting meansincluding a tubular member of insulating material mounted in fixed relation with respect to said tank and a valve housing disposed between said tank and said tubular member, said valve housing being removably mounted upon said tank and having an expansible portion adapted to be brought into unconnected abutting engagement with the end of said tubular member to seal the gas blast conducting means, said valve housing being remo'vable without disturbing the fixed mounting relation of said contact means and said tubular member andsaid tank.

2. In a gas blast circuit interrupter, a gas storage tank, a valve housing removably supported on said tank, said valve housing having a through passage communicating with said tank, a valve member normally closing said passage,

a conduit disposed in alignment with said passage and in fixed relation with respect to said tank, separable contact means fixedly mounted at the end of said conduit, said valve housing having an adjustable member adapted to be brought into unconnected abutting engagement with the end of said conduit to provide a sealed passage from said tank to said contact means, said adjustable member being readily movable out of engagement with said conduit to permit easy removal of said valve housing, said valve housing being removable without dismantling said contact means, said conduit, or said tank.

3. In a gas blast circuit interrupter, a tank I for storing gas under pressure, separable contact means for establishing an arc, and conduit means mounted in fixed relation with respect to said tank glfor conducting a blast of gas from said tank to said contact means to extinguish said arc, said conduit means including a valve housing forming a portion of the conduit and removablyimounted thereon, a valve member in said housing for controlling the. flow of gas to said contacts, said conduit means also including an expansible section expansible to provide an unconnected abutting joint between said valve housing and a portion of said conduit means on the low pressure side of said valve housing, said valve housing being removable without dismantling said contact means, said conduit means or said tank.

4. In a gas blast circuit interrupter, a fixed' mounted tank for storing gas under pressure, a valve housing removably mounted on said tank, said housing having a bore extending therethrough, a valve member normally closing the end of said bore adjacent to the tank, a tubular member fixedly mounted independently of said valve housing and in axial alignment with said bore and means adjustable from the outside of said housing at the other end of said bore for expanding into engagement with the end of said tubular member, and actuating means for opening the valve operative in accordance with opening movement of said contact to cause a blast of gas to fiow from said tank in a straight line to said contacts. 5. In a gas blast circuit interrupter, supporting means, a gas storage tank secured to said supporting means, separable contact means fixedly mounted in spaced relation to said tank and insulated therefrom, means for conducting a blast of gas from said tank to the region of separation 01 said contact means comprising a tubular member of insulating material rigidly mountiii ed on said supporting means and a valve housing disposed between said tank and said tubular member, said valve housing being removably mounted on said tank in gas tight relation therewith and having an expansible conduit portion adapted to be brought in unconnected abutting engagement with the end of said tubular member.

6. In a gas blast circuit interrupter, supporting means, a gas storage tank secured to said supporting means, separable contact means fixedly mounted in spaced relation to said tank and insulated therefrom, means for conducting a blast oi gas in a straight line path from said tank to the region of separation oi. said contact means comprising a tubular member of in sulating material rigidly mounted on said supporting means and a valve housing disposed between said tank and said tubular member and removably secured to said tank in a gas tight relation therewith, and a tubular conduit section having a threaded engagement with said valve housing whereby it is adapted to be brought in unconnected abutting engagement with the end oi. said tubular member to complete the gas blast ,conducting means.

7. In a gas blast circuit interrupter, a gas storage tank having an outlet therefrom, a valve for controlling the fiow of gas from said outlet, a pair oi. separable contacts and a conduit for directing a blast of gas thereto, said contacts and conduit being mounted independently of said valve with one end of the conduit fixed in spaced relation to said outlet, and said valve being removably mounted in the fixed space between said outlet and said end of the conduit and having expansible means adjustable to completely fill said fixed space.

8. In a gas blast circuit interrupter, a gas storage tank having an outlet therefrom, a valve for controlling the flow of gas from said outlet, a pair of separable contacts and a conduit for directing a blast of gas thereto, said contacts I, valve having expansible means adjustable from the outside thereof to completely fill said space between the outlet and the end of the conduit.

JOHN B. MAcNEIlL. ANDREW H. BAKKEN.

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