US3674957A

US3674957A - Gas blast switch

Info

Publication number: US3674957A
Application number: US144765A
Authority: US
Inventors: Gerhard Korner; Wolfgang Schmitz; Friedhelm Dabringhausen; Lothar Gruber
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1970-05-22
Filing date: 1971-05-19
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: DE2024988A1; DE2024988B2; CH514929A; GB1296642A; FR2093567A5; NL7103995A

Abstract

In the gas blast switch disclosed, a first contact member in a gas pressure chamber moves from an open position out of contact with a counter-contact member toward the forward position of the counter-contact member until it hits the latter and drives it backwards against the force of a spring. The counter-contact member forms a gas seal with a valve sleeve that the countercontact member pushes back against the force of a second spring. A spring actuated retaining mechanism holds the sleeve in the back position. When the first contact member is moved into the open position the sleeve is held and the first spring moves the counter-contact member away from the sleeve to open the seal. This releases a flow of gas from the chamber past the contact member. The gas flow strikes a vane in the retaining mechanism. The response of the vane is to release the sleeve. The second spring drives the thus released sleeve into engagement with the counter-contact member to cut off gas flow.

Description

United States Patent Kiirner et a1.

July 4, 1972 FOREIGN PATENTS OR APPLICATIONS 1,427,982 l/1966 France ..200/148 R Primary Examiner-Robert S. Macon Attorney-Toren & McGready [5 7] ABSTRACT In the gas blast switch disclosed, a first contact member in a gas pressure chamber moves from an open position out of contact with a counter-contact member toward the forward position of the counter-contact member until it hits the latter and drives it backwards against the force of a spring. The countercontact member forms a gas seal with a valve sleeve that the counter-contact member pushes back against the force of a second spring. A spring actuated retaining mechanism holds the sleeve in the back position. When the first contact member is moved into the open position the sleeve is held and the first spring moves the counter-contact member away from the sleeve to open the seal. This releases a flow of gas from the chamber past the contact member. The gas flow strikes a vane in the retaining mechanism. The response of the vane is to release the sleeve. The second spring drives the thus released sleeve into engagement with the counter-contact member to cut off gas flow.

11 Claims, 1 Drawing Figure [54] GAS BLAST SWITCH [72] lnventors: Gerhard Kiirner, Schriesheim; Wolfgang Schmitz, Birkenau; Friedhelm Dabringhausen, Mannheim-Wallstadt; Lothar Gruber, Dortmund, all of Germany [73] Assignee: Brown, Boveri & Cie AG, Mannheim, Germany [22] Filed: May 19,1971

[21] Appl. N0.: 144,765

[30] Foreign Application Priority Data May 22, 1970 Germany "P 20 24 988.1

[52] US. Cl ..200/148 BV, 200/148 B [51] Int. Cl. ..H0lh 33/86 [58] Field of Search ..200/148 R, 148 B, 148 BV [56] References Cited UNITED STATES PATENTS 3,475,575 10/1969 Floessel ..200/148 R 3,590,187 6/1971 Kane et a1 ..200/l48 BV P'A'TEN'TEDJHL "4 I972 3, 674. 957

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GAS BLAST SWITCH BACKGROUND OF THE INVENTION This invention relates to gas blast switches or air blast switches for opening and closing the electrical connection in a high-power line, and particularly to such switches in which, during opening of the switch, a blast of gas is directed across the contacts at the instant of separation in order to extinguish an arc.

Such switches are also called gas blast circuit breakers or air blast circuit breakers. Such switches may be opened and closed by directly moving one switching contact against a spring-loaded nozzle-shaped counter-contact which is forced back by the first contact as the switches close and which move with the first contact so as to remain engaged therewith during the first part of the latters opening movement as the switches open. Generally the movement of the first contact is expected to open an outlet valve which forms a gas blast during the opening movement so as to extinguish the arc. Special means may also be used to open and close the outlet valve at the proper time in response to movement of the counter contact.

It has been proposed to utilize the moving or trailing characteristic of the counter-contact for actuating the outlet valve when the counter-contact is in the shape of a nozzle. This helps buid up the required contact force and to produce separation of the contact at a defined velocity after the outlet valve had already been opened. This usually requires coupling of the trailing counter-contact with the auxiliary valve and simultaneously forming the valve body of the outlet valve into a differential piston. The outlet valve then opens briefly during the switching operation. Such control of the outlet valve by means of the counter-contact is complicated and expensive. The outlet valve and the great number of moving parts must be sealed from each other.-

An object of the invention is to avoid these disadvantages. A further object of the invention is to simplify the mechanism for controlling the outlet valve in response to the counter-contact so that the overall switch is easy to manufacture.

SUMMARY OF THE INVENTION According to a feature of the invention these disadvantages are obviated in a gas blast switch where the counter-contact moves part of the way with the first contact as it opens, by utilizing resilient means to press sealing means against the counter-contact so as to form a seal when the counter-contact is forced into the closed position, and by retaining the sealing means in position as the counter-contact follows the first contact during the opening movement so as to break the seal. Breaking of the seal allows gas flow past the contact.

According to another feature of the invention vane means respond to the flow of gas through the open seal and constrain the retaining means to release the seal means so that the resilient means force the seal means toward the counter contact and into sealing engagement therewith. In this manner the gas flow is stopped.

According to still another feature of the invention the sealing means includes a valve sleeve and the second contact includes a cylindrical portion having a round packing engaging an end of the valve sleeve.

According to yet another feature of the invention a high pressure gas chamber is formed around one side of the seal to form the gas flow.

According to yet another feature of the invention the retaining means includes stationary means in sliding engagement with the sleeve and a lock member associated with the sta tionary means and the sleeve.

According to yet another feature of the invention the retaining means include slide means coupled to the vane for causing the lock member to lockingly engage the sleeve and the stationary means when the slide means is in a rest position. Springy means slide the slide means into the rest position. The vane when actuated by movement of gas moves the slide means against the force of the springy means to release the engagement of the lock means with the stationary means and the sleeve.

According to yet another feature of the invention the slide means includes holding means for engaging the lock member so that the slide means is locked against the force of the springy means into an active position.

According to a more specific feature of the invention the retaining means includes a stationary tube having an opening therein and coaxial with the sleeve. The sleeve includes a groove. A ball in the opening engages the groove and a cylinder body slidingly mounted with respect to the tube has a straight portion for forcing the ball into the groove and a recess for receiving the ball. A spring urges the body to a position where the straight surface forces the ball into the groove so as to lock the sleeve in position when the counter-contact is forced by the contact into the closed position.

According to yet another feature of the invention the vane is moved by the gas through the open sea] and moves the body against the force of the spring until the recess can receive the ball.

According to yet another feature of the invention the sleeve includes inclined surfaces in the groove for forcing the ball into the recess when the recess is aligned by the gas with the opening so as to hold it there as the sleeve moves the groove out of alignment and the body is thus held in place against the force of the spring even after movement of the gas stops.

According to still another feature of the invention the recess includes inclined surfaces for forcing the ball into the groove when the fust contact aligns the groove and the sleeve with the opening so that the spring may move the body.

According to yet another feature of the invention the sleeve includes projections for preventing gas flow into the opening.

According to still another feature of the invention the vanes are composed of projections protruding radially outward from the body.

By virtue of these features simple means achieve opening and closing of the outlet valve in dependence upon the trailing movement of the counter-contact. In particular, only those packings or gaskets normally required for an ordinary outlet valve are necessary. The number of moving parts is small and they are simple to manufacture and assemble. The opening time of the seal means can be easily adapted to the require ments of gas flow on the switching zone by the shape of the various members and vanes and particularly by suitable selection of its flow resistance.

According to another feature of the invention a particularly simple embodiment is obtained by including as part of the seal means a sleeve about which the gas flows and which receives the spring that forces it to follow the trailing movement of the counter-contact on the inside. The retaining means are arranged along its outer circumference and are protected against the pressure gas current by means of radial projections. This results in a device having a relatively small circumference whose sensitive parts are protected.

According to another feature of the invention the balls used to lock the sleeve may be replaced by rotary pins. The balls or pins result in a reliable and easily detachable locking arrangement. The strength of this locking arrangement is variable to an extent by varying the number of balls or pins arranged circumferentially.

These and other features of the invention are pointed out in the claims. Other objects and advantages of the invention will become obvious from the following detailed description when read in light of the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a sectional view illustrating a gas blast switch embodying features of the invention, and showing above the center line the switch as enclosed in a metal and in the oft position, and below the center line as an open air switch in the on" position.

PREFERRED EMBODIMENTS OF THE INVENTION In the drawing, a directly driven noule-shaped contact member 1, of a so-called nozzle switch, is actuated by means not shown to move to the right. There the member 1 makes mechanically-resilient electrical! contact with a counter-contact member 2, as shown in the lower section of the drawing. The actuating means for the contact member 1 also withdraw the contact member 1 axially to the left, so as to break the electrical connection with the counter-contact member 2 as shown in the upper section. A spring cup 2a located centrally within the contact member 2 by means of fixed ribs 2b transmits an axial biasing force from a compressed contact spring 3 to the counter-contact member 2. In the connected position shown in the lower section of the counter-contact member 2 is thus resiliently biased against the contact member 1. When the contact member 1 is withdrawn the counter-contact member 2 is constrained by the spring 3 to follow the withdrawing contact member 1 over a distance a. The contact member 1 and counter-contact member 2 are located in a high pressure chamber 4 which is always filled with pressurized gas and which is formed by an enclosing wall 5 and an insulator 6 or by an insulator 7 and a switch chamber 22.

In the on" position the contact member 1 forces the counter-contact 2 to the right against the force of the spring 3 over the trailing distance a. An annular packing 8 carried in the rear end of the counter-contact member 2 cooperates with a valve sleeve 9 to close ofi the high pressure chamber 4. This is done with the aid of a biasing spring 10 that urges the sleeve 9 against the packing 8.

The springs 3 and 10 bear against a support plate 11. An inner guide tube and an outer guide tube project coaxially from the plate 11. The inner guide tube 12 forms a central guide for the valve sleeve 9. Bearings 14 mounted between the sleeve 9 and the guide tube 13 allow for free movement of the valve sleeve 9 over an air retaining packing 15.

At the open extremity of the guide tube 13, suitable bores receive locking balls 16. The guide tube 13 guides a flow responsive body 17 which a spring 18 always urges to the left. The valve sleeve 9 is provided with a groove 19 which is engaged by the balls 16 in the on" position illustrated in the lower section of the drawing. In that position the body 17 locks the sleeve 9 by holding the balls inwardly. A projection 20 limits leftward movement of the body 17 so as to allow the latter to bear inwardly on the balls 16.

In operation the means not shown drive the contact member 1 to the right against the counter-contact member 2 so as to press the latter resiliently to the position shown in the lower section. This compresses the spring 3 and shifts the sleeve 9 to the right against the force of the spring 10. The body 17 then presses the balls 16 into the groove 19 of the sleeve 9. When the actuating means not shown open the contact between the members 1 and 2 by moving the contact member 1 to the left the spring 3 causes the counter-contact member 2 to follow the contact member 1 over the distance a until the members disconnect. The interiorly pressed balls 16 engaging the groove 19 prevent the sleeve 9 from following the Countercontact member 2 toward the left. The packing 8 thus disengages from the left end of the valve sleeve 9. The pressurized gas stored in the high pressure chamber 4 can then flow into a low pressure chamber 21 and 21' through the nozzle-shaped counter-contact 2.

The shape of the spring cup 2a and the switch chamber 22 causes the pressurized gas flowing from the high pressure chamber 4 to the low pressure areas to strike an annular projection 23 on the body 17 and in the path of the flowing gas.

The resistance caused by the projection 23 causes the flowing gas to displace the body 17 to the right. The rightward movement of the body 17 lasts until the balls 16 can be forced outwardly into annular groove 24 on the body 17 by inclined surfaces in the groove 19. This releases the valve sleeve 9 so that the latter is moved to the left by the spring 10. The valve then closes.

When the means not shown again close the gas blast switch by moving the contact member 1 to the right the latter contacts the counter-contact member. It then moves the countercontact member 2 to the right over a distance a. This moves the valve sleeve 9 to the right. The balls 16 can then again engage the groove 19. Inclined surfaces in the groove 24 push the balls 16 into the groove 19 as the spring 18 moves the body 17 toward the projection 20 of the valve sleeve 9. The balls 16 are then retained in the rest position. The pressurized gas accumulating in the low-pressure chamber 21 or 21' is released to the outside through a line 25 or recirculated to the high pressure chamber 4 in a closed cycle through a compressor not shown.

It should be noted that the drawing shows two embodiments of a gas blast switch. One embodiment is shown above the center line and one below. In the embodiment above the center line the chamber 21 differs from the chamber 21' below the line. The switch which is common to both of these embodiments appears as being ofi' above the center line and on below the center line.

While embodiments of the invention have been disclosed in detail, it will be obvious to those skilled in the art that the invention may be embodied otherwise without departing from its spirit and scope.

What is claimed is:

l. A gas blast switch comprising first contact means mova ble between an open and a closed position, second contact means for contacting said first contact means in the closed position and movable partly toward the open position, resilient means for biasing said second contact means toward the open position so that said second contact means contacts said first contact means over a part of its path as said first contact means moves from the closed position to the open position, movable gas seal means for forming at a first position a gas seal with said second contact means when said first contact means forces said second contact means into the closed position, biasing means for urging said gas seal into sealing engagement with said second contact means when said second contact means is moved by said resilient means toward the open position of said first contact means, retaining means for holding said seal means in the first position whereby said second contact means opens the seal between it and said seal means when said second contact means follows said first contact means toward the open position, and vane means coupled to said retaining means and responsive to flow of gas through the open seal for releasing said seal means so said biasing means forces said seal means toward said second contact means and into sealing engagement with said second contact means.

2. A switch as in claim 1, wherein said seal means includes a valve sleeve having a sealing end and wherein said second contact means includes a cylinder-like portion having round packing means engageable with the sealing end of said sleeve.

3. A switch as in claim 1, wherein high pressure chamber means on one side of the seal formed by said seal means is adapted to hold gas under higher pressure than the gas on the other side of the seal.

4. A switch as in claim 2, wherein said retaining means includes stationary means in sliding engagement with said sleeve and a lock member associated with said stationary means in said sleeve.

5. A switch as in claim 4, wherein said retaining means includes a slide means coupled with said vane means for causing said lock member to lockingly engage said sleeve and said sta tionary means when said slide means is in a rest position, springy means for driving said slide means into the rest position, said vane when actuated by movement of gas moving said slide means against the force of the springy means to release the engagement of said lock means with said stationary means and said sleeve.

6. A switch as in claim 5, wherein said slide means includes holding means for engaging said lock member so that said slide means is locked against the force of said springy means to an active position.

7. A switch as in claim 4, wherein said retaining means includes a stationary tube having an opening therein and coaxial with said sleeve, said sleeve having a groove, a ball in said opening engaged with the groove, a cylinder body slidingly mounted with respect to said tube and having a straight portion for forcing said ball into said groove and a recess for receiving the ball, a spring for urging said body to a position wherein the straight portion forces the ball into the groove so as to lock the sleeve in position when the second contact means is forced by movement of the first contact means into the closed position.

8. A switch as in claim 7, wherein said vane is mounted on said body and where movement of gas through the open sea] moves said body against the force of the spring until the recess can receive said ball.

9. A switch as in claim 8, wherein said sleeve includes inclined surfaces in the groove for forcing the ball into the recess when the recess is aligned by the gas moving the sleeve with the opening and holding it there, whereby as said sleeve moves the groove out of alignment said body is thus held in place against the force of the spring even after movement of gas stops.

10. A switch as in claim 9, wherein said recess includes inclined surfaces for forcing the ball into the groove when said first contact means aligns the groove and the sleeve with the opening so that said spring may move said body and the ball into the groove and lock the sleeve.

11. A switch as in claim 10, wherein said sleeve includes blocking means for blocking movement of gas into the openmg.

Claims

1. A gas blast switch comprising first contact means movable between an open and a closed position, second contact means for contacting said first contact means in the closed position and movable partly toward the open position, resilient means for biasing said second contact means toward the open position so that said second contact means contacts said first contact means over a part of its path as said first contact means moves from the closed position to the open position, movable gas seal means for forming at a first position a gas seal with said second contact means when said first contact means forces said second contact means into the closed position, biasing means for urging said gas seal into sealing engagement with said second contact means when said second contact means is moved by said resiliEnt means toward the open position of said first contact means, retaining means for holding said seal means in the first position whereby said second contact means opens the seal between it and said seal means when said second contact means follows said first contact means toward the open position, and vane means coupled to said retaining means and responsive to flow of gas through the open seal for releasing said seal means so said biasing means forces said seal means toward said second contact means and into sealing engagement with said second contact means.

5. A switch as in claim 4, wherein said retaining means includes a slide means coupled with said vane means for causing said lock member to lockingly engage said sleeve and said stationary means when said slide means is in a rest position, springy means for driving said slide means into the rest position, said vane when actuated by movement of gas moving said slide means against the force of the springy means to release the engagement of said lock means with said stationary means and said sleeve.

8. A switch as in claim 7, wherein said vane is mounted on said body and where movement of gas through the open seal moves said body against the force of the spring until the recess can receive said ball.

11. A switch as in claim 10, wherein said sleeve includes blocking means for blocking movement of gas into the opening.