Valve (e.g., Blast Valve Or Pressure Relief Valve) Patents (Class 218/66)
  • Patent number: 11764012
    Abstract: A gas circuit breaker includes a first arc contactor electrically connected to a first lead-out conductor, a cylindrical guide portion provided on a second lead-out conductor side, a trigger electrode arranged to be movable between the first arc contactor and the guide portion, and igniting an arc along with a movement in a first half of a current breaking action, a compression chamber being formed by a cylinder having an outer wall and an inner wall both formed in a cylindrical shape, and a piston sliding between the outer wall and the inner wall, and an insulation nozzle guiding the arc-extinguishing gas to an arc ignited at the first arc contactor. The insulation nozzle is formed integrally with the inner wall of the cylinder.
    Type: Grant
    Filed: March 19, 2019
    Date of Patent: September 19, 2023
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Energy Systems & Solutions Corporation
    Inventors: Yuko Imazawa, Tomoyuki Yoshino, Toshiyuki Uchii, Takato Ishii, Akira Shimamura, Tomohiro Hasegawa
  • Patent number: 11380501
    Abstract: A high voltage electric switch includes contacts with graphite carbon electrode forming the arc gap. In addition, the carbon contacts are located in a chamber containing at least 60% carbon dioxide (CO2) as a dielectric gas to achieve improved arc interrupting performance. In conventional switches, the metallic contacts introduce metallic vapors into the arc plasma that inhibits the ability of the dielectric gas to interrupt high voltage, high current arcs. As the element carbon is inherently present in CO2 gas, the addition of vapors from the carbon electrodes into the dielectric gas does not significantly interfere with the dielectric arc-interrupting performance of the CO2 dielectric gas.
    Type: Grant
    Filed: December 29, 2020
    Date of Patent: July 5, 2022
    Assignee: Southern States LLC
    Inventors: Brian Berner, Joseph R Rostron, Brian Roberts
  • Patent number: 10755879
    Abstract: A circuit breaker including a stationary frame, at least a pair of arc contacts, an actuation rod, a compression chamber in which a portion of the dielectric gas is compressed; a cylinder and a piston connected with the rod, which are movable within the stationary frame along main axis, for compressing the portion of the dielectric gas in the compression chamber; a link mechanism connecting the piston to the rod, wherein the stationary frame includes a cylindrical portion with which each of the piston and of the cylinder are radially in gastight contact and which bounds the compression chamber together with the piston and the cylinder.
    Type: Grant
    Filed: May 18, 2018
    Date of Patent: August 25, 2020
    Assignee: General Electric Technology GmbH
    Inventors: Joel Ozil, Matthieu Barre, Cedrid Delhomme, Nadia Hasnaoui
  • Patent number: 10115548
    Abstract: A gas circuit breaker includes a rod-shaped fixed arc contact, a cylindrical movable arc contact to contact or be separated from the fixed arc contact, a heat puffer chamber storing an arc-extinguishing gas to be blown to an arc generated between the fixed arc contact and the movable arc contact, and an insulator received within a receiving hole formed in a distal end part of the fixed arc contact. An end surface of the insulator on a side of the movable arc contact faces the side of the movable arc contact via an opening end of the housing hole, the end surface on the side of the movable arc contact is disposed closer to the inside of the housing hole than the opening end is, and the insulator is made of an ablation material that is vaporized by heat of the arc.
    Type: Grant
    Filed: January 7, 2015
    Date of Patent: October 30, 2018
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yasunori Nakamura, Yuji Yoshitomo, Daisuke Yoshida
  • Patent number: 9865418
    Abstract: A circuit breaker having first and second electrical contacts configured to generate an electrical arc upon being separated, an arc chamber surrounding at least a portion of a space between the first and second electric contacts, at least one expansion chamber positioned proximate to the arc chamber, and an arc pressure control valve assembly configured to allow threshold-based flow into and out of the at least one expansion chamber. An arc pressure control valve assembly and method of operating a circuit breaker are described, as are other aspects.
    Type: Grant
    Filed: December 8, 2015
    Date of Patent: January 9, 2018
    Assignee: Siemens Industry, Inc.
    Inventor: Guang Yang
  • Patent number: 9704679
    Abstract: A gas circuit breaker including a pair of main contacts is openable inside an insulating tank. A pair of arc contacts is arranged on the inner side of the main contacts, and a puffer cylinder has the main contacts and the arc contacts at an end. A puffer chamber is formed inside the puffer cylinder, and a puffer piston is provided on the inner periphery of the puffer cylinder. An insulating nozzle part is mounted on an end of the puffer cylinder to surround the arc contact. The insulating nozzle part includes a split nozzle base part and a split nozzle end part, and the split nozzle base part has a throat part.
    Type: Grant
    Filed: April 18, 2014
    Date of Patent: July 11, 2017
    Assignee: Hitachi, Ltd.
    Inventors: Daisuke Nomura, Noriyuki Yaginuma, Yuuji Kaneko, Makoto Hirose
  • Patent number: 9640349
    Abstract: The gas circuit breaker is made up of a fixed contact, a movable contact, a sealed tank having the fixed contact and the movable contact therein, an operating mechanism for driving the movable contact, and a mechanism unit for housing a link mechanism for connecting the operating mechanism with the movable contact. The operating mechanism is made up of an opening spring and a closing spring, cases for covering respective peripheries of those elastic bodies, a control mechanism for holding and freeing the driving force of the elastic body, and a link mechanism for conveying the driving force of the elastic body to the movable contact. The opening spring is laterally disposed in the axial direction between the link mechanism and the control mechanism. An integral flange is provided on an opening spring case and a closing spring case.
    Type: Grant
    Filed: November 13, 2014
    Date of Patent: May 2, 2017
    Assignee: Hitachi, Ltd.
    Inventors: Hiroaki Hashimoto, Kenichi Okubo, Go Kobayashi
  • Patent number: 9496107
    Abstract: The present disclosure relates to a circuit breaker of a gas-insulated switchgear, and more particularly, to a self-blast circuit breaker of a gas-insulated switchgear, which reuses arc heat. A self-blast circuit breaker having a heat expansion chamber and a puffer chamber includes auxiliary intake valves which introduce a hot gas exhausted through an inside of an actuating rod, into the heat expansion chamber.
    Type: Grant
    Filed: December 19, 2014
    Date of Patent: November 15, 2016
    Assignee: HYUNDAI HEAVY INDUSTRIES CO., LTD
    Inventor: Hyung-Choon Kim
  • Patent number: 9147539
    Abstract: A high voltage gas circuit breaker, comprises: a fixed unit including a fixed arc contactor and a fixed contactor; and a movable unit including a movable arc contactor and a movable contactor, and configured to selectively contact or be separated from the fixed unit, and wherein the movable unit comprises: a fixed cylinder; a compression cylinder slidably-installed in the fixed cylinder; a movable rod penetratingly-coupled to the compression cylinder, and configured to transmit an adjusting force of an operator; a pressing member installed on an inner bottom part of the compression cylinder; and a compression plate supported by the pressing member, and up-down moving in the compression cylinder by a pressure of an expansion chamber.
    Type: Grant
    Filed: May 23, 2014
    Date of Patent: September 29, 2015
    Assignee: LSIS Co., Ltd.
    Inventor: Man Seung Yeon
  • Patent number: 9035211
    Abstract: A gas-insulated circuit interrupter is disclosed, the interrupter having an improved design for quenching electrical arcs. The interrupter includes a first contact and a second contact configured to alternatively connect to and disconnect from the first contact. One or both of the contacts are at least partially contained in an arcing chamber. The arcing chamber includes the point at which the contacts connect during current-carrying operation of the interrupter. The arcing chamber is at least partially surrounded by a heating chamber for accommodating a quenching gas. A channel connects the heating chamber and the arcing chamber and is positioned to direct the quenching gas toward the first contact and the second contact arcing area. One or more valves direct gas from the arcing chamber to the heating chamber when the interrupter is operated to interrupt a current.
    Type: Grant
    Filed: July 20, 2012
    Date of Patent: May 19, 2015
    Assignee: Pennsylvania Breaker, LLC
    Inventor: Daniel C. Schiffbauer
  • Publication number: 20150108091
    Abstract: A mechanical switch in the form of a bypass switch assembly is arranged between two electrical conductors (busbars) and stays open during normal operation. When a cell fault happens, the fault and bypass information is transmitted to an actuator (acting as a trigger circuit) which activates inter alia a gas generator producing huge volume of gas in a very short time. The gas pressure pushes a movable member to bridge the two electrical conductors with ultrafast speed.
    Type: Application
    Filed: June 13, 2012
    Publication date: April 23, 2015
    Applicant: ABB TECHNOLOGY LTD
    Inventors: Åke Öberg, Filippo Chimento, Jian Qin, Liwei Wang, Ola Jeppsson
  • Patent number: 8859925
    Abstract: An electric switchgear includes an interrupter unit having a first connecting line and a second connecting line. The interrupter unit is disposed inside a fluid-tight encapsulating housing that is filled with an electrically insulating fluid. The interrupter unit is further surrounded by a shielding housing in at least some sections. The first connecting line has a flow channel for the fluid. A first outlet opening of the flow channel leads to the shielding housing and a second outlet opening leads to the exterior of the shielding housing.
    Type: Grant
    Filed: February 7, 2011
    Date of Patent: October 14, 2014
    Assignee: Siemens Aktiengesellschaft
    Inventors: Norbert Lüthy, Tomasz Magier, Manfred Meinherz, Clemens Rüthnick
  • Patent number: 8822868
    Abstract: A simplified construction of a gas-insulated high-power circuit breaker with a saving of components is achieved by at least one hole and at least one leaf spring, which is fastened on one side and is elastically bendable in dependence upon the pressure of the insulating gas in the compression volume, being formed in a valve plate of the valve. The bendable spring closes off the hole when the circuit breaker closes and opens it when the circuit breaker opens as soon as the pressure of the compressed insulating gas in the compression volume exceeds the value of the gas pressure in the low-pressure chamber by at least two bar.
    Type: Grant
    Filed: September 17, 2013
    Date of Patent: September 2, 2014
    Assignee: ABB Technology AG
    Inventors: Timo Kehr, Olaf Hunger, Jurg Nufer, Daniel Ohlsson, Navid Mahdizadeh, Javier Mantilla, Stephan Grob, Mathias-Dominic Buergler, Nicola Gariboldi
  • Patent number: 8629366
    Abstract: Exemplary embodiments are directed to a medium voltage circuit breaker arrangement that includes at least one pole part housing for accommodating a pair of coaxially arranged electrical contacts, wherein one electrical contact of the pair of electrical contacts is axially movable via a jackshaft arrangement which is accommodated in a recasted sheet metal housing, and driven by an actuator unit. The sheet metal housing forms a suspension construction for the at least one pole part housing and the jackshaft arrangement and the corresponding actuator unit forming a module. An additional housing part is provided for covering at least the actuator unit of the module in order to define the outer geometrical dimensions of the circuit breaker arrangement.
    Type: Grant
    Filed: May 21, 2012
    Date of Patent: January 14, 2014
    Assignee: ABB Technology AG
    Inventor: Christian Reuber
  • Patent number: 8410388
    Abstract: A self-blowout circuit breaker is disclosed which includes contacts for connecting or disconnecting a circuit, a heating volume, a compression volume and an exhaust volume. The compression volume can be connected to the heating volume by at least one first valve, which heating volume is in turn connected to an arc zone. Upon the disconnection of the circuit, while a first arcing contact is being disconnected from an associated second arcing contact, an arc is produced between the two arcing contacts in the arc zone. The compression volume is separated from the exhaust volume by a combined filling and overpressure valve which is formed as at least one plate, and has at least one tab which is formed in the plate.
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: April 2, 2013
    Assignee: ABB Technology AG
    Inventors: Martin Kriegel, Daniel Ohlsson, Juerg Nufer, Navid Mahdizadeh, Olaf Hunger, Timo Kehr
  • Patent number: 8399791
    Abstract: The invention relates to an interrupter arrangement (1) having a switching tube (3) comprising a switch gas outlet opening (5). The switching tube (3) is connected to a coupling section (9) of a drive rod (10) in the region of the switch gas outlet opening (5). The coupling section (9) is protected from switch gasses emitted from the switch gas outlet opening (5) by means of a shield (15).
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: March 19, 2013
    Assignee: Siemens Aktiengesellschaft
    Inventors: Joachim Gericke, Ronald Puls
  • Patent number: 8299385
    Abstract: Disclosed are a valve for a gas circuit breaker, and a gas circuit breaker having the same. The gas circuit breaker comprises a cylinder constituting appearance of the gas circuit breaker, and providing a gas flow path therein, a partition plate having passing holes, and configured to partition inside of the cylinder, a sleeve concentrically disposed in the cylinder, a valve body inserted into the sleeve, and mounted below the partition plate so as to perform a reciprocation along the sleeve, an elastic means configured to upwardly apply an elastic force on a bottom surface of the valve body, and a blocking plate inserted into the sleeve, and mounted between the valve body and the partition plate so as to be moveable in upper and lower directions, wherein the valve body is provided with discharge openings, and the discharge openings are open and closed by movements of the blocking plate.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: October 30, 2012
    Assignee: LS Industrial Systems Co., Ltd.
    Inventors: Chae Yoon Bae, Joung Ung Choi
  • Patent number: 8232497
    Abstract: A relief valve for discharging a dielectric gas between two volumes (V1, V2) of a high-voltage or medium-voltage interrupting chamber. There is used as a closure member a flexible metal blade secured to the body, the closure member therefore being opened by deformation of the flexible blade from a closed position (FIG. 1) in which it is pressed against a closure member seat formed in the body to a fully open position in which it fits closely against a stop member secured to the valve body while remaining within its elastic limit, the open passage for the gas being open in this fully open position (FIG. 1A) and the return of the blade from its fully open position to its closed position being possible because of its flexibility.
    Type: Grant
    Filed: June 25, 2010
    Date of Patent: July 31, 2012
    Assignee: Areva T & D SAS
    Inventors: Cyril Gregoire, Roger Ledru, Wolfgang Grieshaber
  • Patent number: 8063333
    Abstract: A limited flash-over electric power switch uses a dielectric gas regulator and a flash-over arrestor to greatly diminish the occurrences of high voltage flash-over during operation of a circuit interrupter. The dielectric gas regulator prevents the flow of the dielectric gas into the arc gap during an initial portion of the opening stroke of the interrupter contacts. Once the arc gap is sufficiently wide to greatly diminish the likelihood of a high voltage flash-over, the dielectric gas regulator allows the dielectric gas to flow into the arc gap to extinguish the arc. The flash-over arrestor snubs out incipient flash-over that may occur as the arc attempts to reform across the arc gap. The flash-over arrestor may be a conductive ring located on the interior surface of the nozzle in the region of the orifice.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: November 22, 2011
    Assignee: Southern States, Inc.
    Inventors: Joseph R. Rostron, Bradley J. Schafer, Soung Hwan Lyu, Brian Roberts, Richard Burge
  • Publication number: 20110163069
    Abstract: The high-voltage switch exhibits a compression space of small dimensions, in which, on interruption of a current, insulating gas exhibiting quenching characteristics is compressed mechanically to form quenching gas with the aid of an operating mechanism of the switch. When a small current is interrupted, a sufficient quantity of quenching gas can thus be provided with little mechanical operating force. When a large current is interrupted, quenching gas communicates from the compression space into an expansion volume above a response pressure, keeping the operating force low, of a pressure relief valve. A large quantity of quenching gas is then available for successfully interrupting a large current whilst the operating force is kept low.
    Type: Application
    Filed: December 31, 2010
    Publication date: July 7, 2011
    Applicant: ABB RESEARCH LTD
    Inventors: Daniel Ohlsson, Martin Kriegel, Navid Mahdizadeh, Timo Kehr
  • Patent number: 7820933
    Abstract: A circuit breaker comprises a puffer volume (9) and at least one overpressure valve (16) for discharging gas from the puffer volume (9), if the pressure therein exceeds a given threshold. The overpressure valve (16) is formed by a piston (17) and a spring (19) as well as by a cavity (18) in the stationary support body (10) of the moveable contact assembly (2). The overpressure valve (16) is of compact and simple design, has low hysteresis and large cross-section.
    Type: Grant
    Filed: May 15, 2007
    Date of Patent: October 26, 2010
    Assignee: ABB Technology AG
    Inventors: Helmut Heiermeier, Kurt Kammerl, Timo Kehr, Stephan Grob
  • Patent number: 7202435
    Abstract: An exemplary circuit breaker includes at least one arcing chamber that is filled with isolating gas, extends along a longitudinal axis, is designed to be essentially radially symmetrical, contains an arc area and has at least two power contact pieces. At least one of the power contact pieces is in the form of a moving or stationery tubular hollow contact, which is provided for dissipating hot gases from the arc area into a concentrically arranged exhaust body. A deflection device, which interacts with at least one opening in the hollow contact, is arranged on the side of the hollow contact facing away from the arc area, and radially deflects hot gases into the exhaust volume, which is connected through at least one second opening to an arcing chamber volume. An increased disconnection rating is achieved by providing at least one intermediate body between the hollow contact and the exhaust body.
    Type: Grant
    Filed: February 23, 2005
    Date of Patent: April 10, 2007
    Assignee: ABB Schweiz AG
    Inventors: Max Claessens, Stephan Grob, Xiangyang Ye
  • Patent number: 6872907
    Abstract: This circuit-breaker has at least one arcing chamber which is filled with isolating gas, extends along a longitudinal axis, is designed to be essentially radially symmetrical, contains an arc area and has at least two power contact pieces. At least one of the power contact pieces is in the form of a moving or stationery tubular hollow contact, which is provided for dissipating hot gases from the arc area into a concentrically arranged exhaust body. A deflection device, which interacts with at least one opening in the hollow contact, is arranged on the side of the hollow contact facing away from the arc area, for the radial deflection of the hot gases into the exhaust volume, which is connected through at least one second opening to an arcing chamber volume. The aim is to increase the disconnection rating of this circuit-breaker. This is achieved by providing at least one intermediate body between the hollow contact and the exhaust body.
    Type: Grant
    Filed: September 12, 2003
    Date of Patent: March 29, 2005
    Assignee: ABB Schweiz AG
    Inventors: Max Claessens, Stephan Grob, Xiangyang Ye
  • Patent number: 6744001
    Abstract: A high-voltage circuit-breaker including a valve for decompressing a thermal blast chamber includes two contacts disposed in a breaking space which is delimited by a blast nozzle and contains a dielectric gas. It further includes a thermal blast chamber which communicates with the breaking space via a throat of the nozzle and with an expansion space via an evacuation passage which can be shut off by a valve. The valve opens when the pressure in the thermal blast chamber is greater than a particular threshold to evacuate the pressurized gas from the chamber. The evacuation passage is formed in the nozzle and defines a circular volume within the thickness of the nozzle, following its general shape, and opening into the expansion space downstream of the breaking space relative to the throat.
    Type: Grant
    Filed: March 12, 2003
    Date of Patent: June 1, 2004
    Assignee: Alstom
    Inventors: Denis Dufournet, Michel Perret
  • Patent number: 6730871
    Abstract: A hollow contact tube is provided in a compressed gas-blast circuit breaker in order to improve dielectric properties. The outlet (6) of said contact tube cooperates with a deflecting body (9) and is surrounded by a fixed substantially hollow cylindrical flow director (8).
    Type: Grant
    Filed: May 29, 2002
    Date of Patent: May 4, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventor: Friedrich Loebner
  • Patent number: 6207918
    Abstract: The invention relates to a compressed gas switch with two contact pieces, a contact element by-passing the contact pieces when in the on position, and two isolating distances connected to each other in series. The second contact piece opposing the first isolating distance is arranged axially by an annular piston to be displaceable forming a switching chamber. The switching chamber is separated from the heating chamber by a bulkhead partition having a current-dependent valve, and the second isolating distance is produced after opening of a blowing hole located between the second contact piece and the contact element.
    Type: Grant
    Filed: September 10, 1999
    Date of Patent: March 27, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Dieter Lorenz, Bernd-Ulrich Habedank
  • Patent number: 6163001
    Abstract: Arranged in the continuation of an arcing chamber (16) bounded by consumable rings (32a, 32b) are pressure chambers (25a, 25b) which are connected in each case to a heating volume (18), which concentrically surrounds the arcing chamber (16), via a return channel (28; 28b), which is rotationally symmetrical with reference to the switching axis and is at least initially of increasing cross section, and a non-return valve (29a; 29b). A circumferential blowout slot (19) opening into the arcing chamber (16) between the consumable rings (32a, 32b) issues from the heating volume (18). The pressure chambers (25a, 25b) are, moreover, connected via in each case a plurality of exhaust tubes (34a, 34b) to exhaust volumes (30a, 30b) and to one of them also via a pressure relief valve (37).
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: December 19, 2000
    Assignee: ABB Research Ltd.
    Inventors: Lukas Zehnder, Kurt Kaltenegger, Lutz Niemeyer, Thomas Schoenemann, Gunter Speckhofer
  • Patent number: 5898150
    Abstract: A gas-blast circuit-breaker includes a jacket filled with a dielectric gas. A mobile arc contact cooperates with a fixed arc contact within the jacket. The mobile arc contact is part of a mobile contact assembly which is displaceable axially in the jacket between a closed position and an open position. The mobile contact assembly includes a first tube carrying the mobile arc contact and a second tube, which is coaxial with the first tube, carrying a mobile permanent contact with a gas blast nozzle coupled thereto. A ring joins the first tube and the second tube to define a gas-blast chamber and a compression chamber on opposite sides of the ring. The compression chamber communicates with the gas-blast chamber. An annular piston having an annular recess closes the compression chamber. A compression spring influences the annular piston against a fixed front stop.
    Type: Grant
    Filed: May 9, 1997
    Date of Patent: April 27, 1999
    Assignee: Gec Alsthom & D Sa
    Inventors: Bernard Gallix, Roger Ledru, Antoine Tolossi
  • Patent number: 5898149
    Abstract: This power circuit-breaker has at least one cylindrically constructed arcing chamber which is provided with a stationary contact, with a moving contact and with a quenching zone between the two contacts. A shaft of the moving contact is permanently connected to a blowout volume which is closed off on the stationary contact side by an insulating nozzle through which at least one flow channel passes. The arcing chamber has a first compression volume which is operatively connected to the blowout volume and to a second compression volume. It is intended to provide a power circuit-breaker in which the blowing-out of the arc with pure SF.sub.6 gas is made stronger. This is achieved by providing a moving auxiliary piston between the first compression volume and the second compression volume and by the auxiliary piston being connected to the moving contact via a direction-changing device.
    Type: Grant
    Filed: June 12, 1996
    Date of Patent: April 27, 1999
    Assignee: Asea Brown Boveri AG
    Inventors: Ernst Berger, Christian Lindner
  • Patent number: 5808257
    Abstract: A gas-blast gas-insulated high-voltage circuit-breaker comprises a fixed main contact, a fixed arc contact and a mobile assembly comprising a main contact, an arc contact and a compression volume cooperating with a fixed piston and communicating with a blast volume leading to a blast nozzle. The compression volume is provided with a valve preventing the gas passing from the blast volume to the compression volume. The piston comprises openings for evacuating the gas from the compression volume during tripping, these openings being closed between the start of compression of the compression volume and the closure of the valve and open upon closure of the valve.
    Type: Grant
    Filed: July 22, 1997
    Date of Patent: September 15, 1998
    Assignee: GEC Alsthom T & D SA
    Inventor: Edmond Thuries
  • Patent number: 5589673
    Abstract: A self-blow-out switch having a compression device has a pressure chamber heated by electric arc energy connected to a compression space, optionally with valve control. The compression space is connected to a low-pressure space via a pressure relief valve and a refill valve. Two valve disks of the relief and refill valves, which are located between the compression space and the low-pressure space are designed as two concentric washers of different diameters, lying in direct contact with each other and partly overlapping each other, and integrated to form a single valve unit.
    Type: Grant
    Filed: May 15, 1995
    Date of Patent: December 31, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventors: Volker Lehmann, Heiner Marin, Ingolf Reiher
  • Patent number: 5561280
    Abstract: A compressed gas-blast circuit breaker including a pump cylinder which is moved along with a movable first contact piece. The pump cylinder surrounds a pumping space and a blast chamber, the latter of which is fluidly connected to a first blast nozzle surrounding the first contact piece. A pump piston is supported on a fixed support part via toggle levers, and a toggle joint of the toggle levers is pivoted to a drive rod via a rocker. At the start of a switch-off stroke, an initial bent position of the toggle lever is lessened, intensified after the straightened position has been passed, then lessened again and intensified again after the straightened position has been passed once more. The oscillation of the toggle lever about the straightened position permits the pump piston to be virtually stationary, while an intermediate bottom, which separates the pumping space from the blast chamber, approaches the pump piston in order to reduce the pumping volume.
    Type: Grant
    Filed: May 15, 1995
    Date of Patent: October 1, 1996
    Assignee: Gec Alsthom T&D AG
    Inventor: Johannes Blatter