US3683141A

US3683141A - Gas blast interrupters

Info

Publication number: US3683141A
Application number: US49066A
Authority: US
Inventors: Cecil Arthur Fawdrey; John Robert Simms; Derek Kenworthy; Albert Roxburgh; David Hobbs
Original assignee: Associated Electrical Industries Ltd
Current assignee: Associated Electrical Industries Ltd
Priority date: 1968-12-23
Filing date: 1970-06-23
Publication date: 1972-08-08
Anticipated expiration: 1989-08-08
Also published as: AU1273970A; GB1282570A; GB1282569A

Abstract

A gas blast interrupter has two hollow contact assemblies enclosed in a housing which can be filled with compressed air. A main exhaust valve, when opened, discharges compressed air from the interior of one contact assembly and thereby brings about separation of its contact making part from the contact making part of the second contact assembly. A further exhaust valve, when opened, discharges compressed air from the housing through the second contact assembly. The interrupter has a control valve having a first operative position in which compressed air is utilized to bring about the sequential opening of the main exhaust valve and the further exhaust valve and to close those valves after their contact making parts have separated, and having a second operative position in which compressed air is utilized to cause the contact making parts to engage and the contact assemblies and the housing to be filled with compressed air.

Description

United States Patent Fawdrey et all.

[54] GAS BLAST INTERRUPTERS [72] Inventors: Cecil Arthur Fawdrey, Manchester; John Robert Simms, Stalybridge; Derek Kenworthy, Flixton; Albert Roxburgh, Appleton, near Warring ton, all of England; David Hobbs, deceased, late of Urmston, England by Jeanie Wright Hobbs, administratrix [73] Assignee: Associated Electrical Industries Limited, London, England [22] Filed: June 23, 1970 [21] Appl. No.: 49,066

[52] US. Cl. ..200/148 B, 200/148 D [51] Int. Cl. ..Hlh 33/86 [58] Field of Search ..200/l48, 148 B, 148 D [56] References Cited UNITED STATES PATENTS 3,278,711 /1966 Thuriesetal. ..200/148,B

[ Aug. 8, 1972 Primary Examiner-Robert S. Macon Attorney-Larson, Taylor and Hinds [57] ABSTRACT A gas blast interrupter has two hollow contact assemblies enclosed in a housing which can be filled with compressed air. A main exhaust valve, when opened, discharges compressed air from the interior of one contact assembly and thereby brings about separation of its contact making part from the contact making part of the second contact assembly. A further exhaust valve, when opened, discharges compressed air from the housing through the second contact assembly. The interrupter has a control valve having a first operative position in which compressed air is utilized to bring about the sequential opening of the main exhaust valve and the further exhaust valve and to close those valves after their contact making parts have separated, and having a second operative position in which compressed air is utilized to cause the contact making parts to engage and the contact assemblies and the housing to be filled with compressed air.

7 Claims, 3 Drawing Figures I 95 2725 i7 99l9 2i 5 l 13 57 B5 7' 83 79 A 1 1 co Waco?Assay micmax/,0 ice 9104707 5 43 1 49 CI-.22. 65 Ill/ 1 I/ I, l u ll a 01101 02 4 31,all $76; I I/ l I I I 5 7 1 l I 1529 312311 9 3337 74139 89 63 3 PATENTEDMJQ 81972 SHEET 3 BF 3 m mm 5 am .N 200 b MNR This invention relates to gas blast interrupters comprising two relatively movable contact assemblies enclosed in a housing which is normally filled with a compressed gas, usually compressed air, the gas being discharged to atmospheric pressure to bring about separation of the contact making parts of the two contact assemblies.

The contact assemblies of gas blast interrupters are formed by two hollow structures each having associated therewith anexhaust valve, the main exhaust valve which is associated with the movablecontact assembly being arranged to discharge compressed gas from the interior of the movable contactassembly and bring about separation of the contact making parts, and the exhaust valve which is associated with the stationary contact assembly being arranged to assist .the discharge of compressed gas from the interior of the housing through the hollow stationary contact assembly when the contact making parts have separated, and to cause a blast of the discharging gas to travel across the path of an are which forms between the contact making parts when they separate. The exhaust valves need to be opened andclosed inxthecorrect sequence and to this end elaborateelectrical or pneumatic control devices have been providedhitherto.

An object of the invention is to. simplify the operation and control of a gas blast interrupter.

According to the present invention a gas blastinterrupter comprises first and second hollow; contact assemblies enclosed in a housing adapted to be filled with a compressed gasa main exhaust valve openable to discharge compressed gas from the interior of the first contactassembly and bring about separation of its contact making part from the contact making part of the second contact assembly, a further exhaust valve openable to .assist the discharge of compressed gas from the housing through the second contact assembly, and a control valve having a first operative position in which the compressed gas is utilized to bring about the sequential opening of the main exhaust valve and the further exhaust valve and to close these valves after the contact making parts have'been separated, and having a second operative position in which the compressed gas is utilized to cause the contact making parts to engage and the contact assemblies to be filled with compressed gas.

The control valve may be a slide valve having a first operative position in which compressed gas within. the first contact assembly is diverted to operate a piston of the main exhaust valve and thereby open the main exhaust valve to atmosphere, the reduced pressure ensuing in the first contact assembly being utilized to separate the contact making parts and open the further exhaust valve to atmosphere. Both exhaust valves may be arranged to be reclosed by return springs which operate automatically when the pressure in the housing has fallen following the opening of the two exhaust valves. The second operative position of the slide valve causes a supply of compressed gas to be diverted into the first contact assembly and operate a piston adapted to move the contact making parts into. engagement, whereupon both contact assemblies are filled with compressed gas.

' port 47 which. communicates slide valve 61,

cantilever fashion froma verticallydisposed support column 3 and accommodates a first tubular. contact assembly 7 and a second tubular contact assembly 5. The second contact assembly 5 comprises a tubular contact member 9 which is slidably supported in a tubular sup :port member 11 and hasat its contact making end an air blast nozzle 13 which communicates with an air discharge port 15 by way of an exhaust valve 17 housed within the contact assembly 5. The exhaust valve 17, which is of the kind described in our co-pending US. Pat. application Ser. No. 61032, comprises a piston 19 secured to the contact member 9 and slidable within a chamber 21 formed in the support member 11. A plurality of ports 23 in the wall of thecontact member 9 lead from the part of the chamber 21 on one side of the piston 19 to the interior of the contact member 9. Further ports 25 lead from the interior of the contact member 9 to a further chamber 27 formed in the end of the support member 11 adjacent to the discharge port 15. A valve 29 carried on. the end of the contact member 9 is arranged to open and close the discharge port 15 and is urged towards the closed position by a helical spring 31 interposed between the piston 19 and the end wall of the chamber 21.

The first contact assembly 7.comprises a tubular contact member. 33 slidably mounted in a tubular support :member, 35 and connected by webs '37 to a tubular operating member 39 which extends axially within the supportmember 35. A helical spring 41 surrounding the operating member 39 is arranged to urge the contact member 33 towards the contact member 9. A "piston 43 connected to the operatingmember 39 is with a via port 57 with the interior of the support column 3. A further port 49 in the chamber 45 is arranged to be opened and closed by a valve 51 carried by rod 53 which extends into the operating member 39 and is urged towards the port 49 by a helical spring 55 housed within the operating member39. Aduct 59 leads from the port 49 to a slide valve 61 arranged to connecta port 63 at the end of the duct 59 to the interior of the column 3 or toconnect the port 63 to a further duct 65 leading to a main exhaust valve 67 at the top of the support column 3. The

which forms thecontrol valve of the interrupter, is arranged to be operated by a pull rod 69 which extends down the interior of the support column 3. The exhaust valve 67 comprises a piston 71 slidably mounted in a chamber 73 and urged downwards against a valve seat 75 by a helical spring 77. The lower end of the piston 71 is arranged to open and close an exhaust port 79 which connects the interior of the support member 35 to atmosphere through an airduct 81,

slidably mounted within a chamber 45 provided while the upper end of the piston 71 is arranged to open and close two

further ports

83 and 85 which connect the interior of the chamber 73 to atmosphere.

The air blast interrupter operates in the following manner. To close the

contact members

9 and 33, assume that the slide valve 61 has been moved from the position shown in FIG. 3 to the position shown in FIG. 1 so that air under pressure in the support column 3 enters the duct 59 through the port 63 filling the chamber 45 and thus balancing the air pressure across the piston 43 and causing it together with operating member 39 and contact member 33 to be urged to the left by the spring 41 until contact member 33 engages contact member 9. All parts of the interrupter with the exception of the two chambers connected by the duct 65 are now filled with air at full pressure.

To trip the interrupter the pull rod 69 is moved downwards against the pressure of the spring 91 so that the slide valve 61 moves to the position shown in FIG. 2 in which the duct 65 is connected to the duct 59 through the port 63. Compressed air from the chamber 45 enters the duct 65 and forces the piston 71 upwards against the pressure exerted by the spring 77, the upward movement being controlled by the escape of air through damping holes 93 provided in the wall of the chamber 73. The upward movement of the piston causes the compressed air inside the contact assembly 5 to discharge to atmosphere through the duct 81 and the exhaust port 79.

The pressure drop across the contact member 33 causes this contact member to retract into the support member 35, and during the initial part of this movement the contact member 9 follows contact member 33, being moved by the piston 19 which is actuated by the difference in the air pressures on the opposite sides of the piston 19 resulting from compressed air flowing through the ports 23 into the interior of the contact member 9. The movement of the piston 19 causes the valve 29 to move away from the air discharge port 15, allowing compressed air within the contact member 9 and support member 11 to be discharged to atmosphere through the port 15. The piston 19 comes to rest against the end wall of the chamber 21 and halts the movement of the contact member 9. When the

contact members

9 and 33 separate, compressed air from the space 87 within the housing 1 rushes into the nozzles 13 at the ends of the

contact members

9 and 33 so that a blast of air travels across the path of an are which forms between the

contact members

9 and 33 when they separate. Compressed air entering the nozzles 13 is discharged to atmosphere through exhaust ports 15 and 79 and is replenished by compressed air entering the space 87 through the port 89. The movement of the moving contact member 33 into the support member 35 moves the piston 43 to the right so that it closes port 47, thus shutting off the supply of compressed air to the chamber 45. The valve 51 closes the port 49 so that piston 43 acts as a damper, and the contact member 33 continues its movement to the right until the piston 43 engages with the seat 97. The separation of the contact members at this time is arranged to be such as to interrupt an electric current of given magnitude flowing between the

contact members

9 and 33. When the piston 71 has reached the full extent of its upward movement port 85 is uncovered so that the compressed air in the duct 65 is discharged to atmosphere. Since the compressed air supply to the duct 65 is cut off by the piston 43 and valve 51, the spring 77 urges the piston 71 downwards so that the exhaust port 79 is closed by the lower end of the piston 71. During the movement of the contact member 33 compressed air from behind the piston 19 flows through orifice 99 into the interior of the contact member 9 until the air pressures on opposite sides of the piston 19 are substantially equal. The piston 19 is then urged to the left by the spring 31, moving the contact member 9 to its original position and causing the valve 29 to close port 15. The separation between the

contact members

9 and 33 after the contact member 9 has moved to its original position as shown in FIG. 3, is arranged to be sufficient to withstand a given voltage between the contact members. The

contact members

9 and 33 are held open by the difierential pressure across the piston 43.

Controlling the separation and re-engagement of the contact making parts of the interrupter by means of a single slide valve considerably simplifies the operating mechanism required and enables a simple pull-rod arrangement to be utilized when the interrupter has to be actuated from a remote position.

We claim:

1. A gas blast interrupter comprising:

a. a housing for, during operation, containing a compressed gas;

b. first and second hollow contact assemblies disposed in the housing;

c. a main exhaust valve for, when open, discharging compressed gas from the interior of the first contact assembly and for bringing about separation of a contact making part thereof from a contact making part of the second contact assembly;

. a further exhaust valve for, when opened, assisting the discharge of compressed gas from the housing through the second contact assembly, and

e. a single control valve having a first operative position in which the compressed gas within the housing is utilized to bring about the sequential opening of the main exhaust valve and the further exhaust valve and to close both exhaust valves after the contact making parts have separated, and having a second operative position in which compressed gas from an external supply is utilized to cause the contact making parts to engage and the contact assemblies to be filled with compressed gas.

2. A gas blast interrupter as claimed in claim 1, wherein the control valve is a slide valve having a first operative position in which the compressed gas within the first contact assembly is diverted to operate a piston of the main exhaust valve and thereby open the main exhaust valve to atmosphere, the reduced pressure in the first contact assembly being utilized to separate the contact making parts and open the further exhaust valve to atmosphere, and having a second operative position in which the supply of compressed gas from the external supply is diverted into the first contact assembly and operates a piston adapted to move the contact making parts into engagement, and causes both contact assemblies to be filled with compressed gas.

3. A gas blast interrupter as claimed in claim 1, wherein the main exhaust valve is arranged to be reclosed by a return spring which operates automatically when the pressure in the housing has fallen to a predetermined value following the opening of the two exhaust valves.

4. A gas blast interrupter as claimed in claim 1, wherein the further exhaust valve is arranged to be reclosed by a return spring which operates automatically when the pressure in the housing has fallen to a predetermined value following the opening of the two exhaust valves.

5. A gas blast interrupter as claimed in claim 1, wherein the main exhaust valve comprises a piston slidably mounted in a chamber and movable to open and close an exhaust port which connects the interior of the first contact assembly to atmosphere, the piston being movable to open the exhaust port by supplying compressed gas to the chamber by way 'of the control valve.

6. A gas blast interrupter as claimed in claim 5, wherein further movement of the piston is arranged to open a further exhaust port through which compressed gas in the chamber is discharged to atmosphere, and a return spring is arranged to return the piston to its original position after the further exhaust port has been opened and the compressed gas in the chamber has been discharged to atmosphere.

7. A gas blast interrupter as claimed in claim 1, wherein the housing is supported on a vertically disposed column and the control valve is operated by a pull rod which extends down the interior of the column.

Claims

1. A gas blast interrupter comprising: a. a housing for, during operation, containing a compressed gas; b. first and second hollow contact assemblies disposed in the housing; c. a main exhaust valve for, when open, discharging compressed gas from the interior of the first contact assembly and for bringing about separation of a contact making part thereof from a contact making part of the second contact assembly; d. a further exhaust valve for, when opened, assisting the discharge of compressed gas from the housing through the second contact assembly, and e. a single control valve having a first operative position in which the compressed gas within the housing is utilized to bring about the sequential opening of the main exhaust valve and the further exhaust valve and to close both exhaust valves after the contact making parts have separated, and having a second operative position in which compressed gas from an external supply is utilized to cause the contact making parts to engage and the contact assemblies to be filled with compressed gas.

5. A gas blast interrupter as claimed in claim 1, wherein the main exhaust valve comprises a piston slidably mounted in a chamber and movable to open and close an exhaust port which connects the interior of the first contact assembly to atmosphere, the piston being movable to open the exhaust port by supplying compressed gas to the chamber by way of the control valve.