US3745285A - Silencer for high-voltage gas-blast circuit breaker - Google Patents

Silencer for high-voltage gas-blast circuit breaker Download PDF

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Publication number
US3745285A
US3745285A US00254963A US3745285DA US3745285A US 3745285 A US3745285 A US 3745285A US 00254963 A US00254963 A US 00254963A US 3745285D A US3745285D A US 3745285DA US 3745285 A US3745285 A US 3745285A
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US
United States
Prior art keywords
gas
silencer
circuit breaker
expansion chamber
rubber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00254963A
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English (en)
Inventor
W Kramer
D Schnee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Switzerland
Original Assignee
Bbc Brown Boveri & Cie
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
Application granted granted Critical
Publication of US3745285A publication Critical patent/US3745285A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/53—Cases; Reservoirs, tanks, piping or valves, for arc-extinguishing fluid; Accessories therefor, e.g. safety arrangements, pressure relief devices
    • H01H33/58—Silencers for suppressing noise of switch operation

Definitions

  • a silencer for a high-voltage circuit breaker of the gasblast type includes an expansion chamber into which Foreign APPllcatmn Priority Data pressurized gas from the switch contact chamber flows June 9, 1971 Germany P 21 28 632.8 after passing through one of the contact members and a discharge valve.
  • Thewall of the expansion chamber [52] U.S. Cl. 200/148 C, 200/150 H is at least partially constructed from a rubber-elastic [51] Int. Cl.
  • the present invention relates to an improved construction for a silencer for use in conjunction with highvoltage circuit breakers of the gas-blast type for the purpose of reducing the level of the noise created by discharge of the pressurized gas to the atmosphere after performing its work in blasting the are generated by the circuit breaker contacts as they disengage.
  • the improved silencer structure features an expansion chamber for the gas, the wall of the chamber being made at least in part from a rubber-elastic material having pores which open up to pass the gas as backpressure builds within the chamber.
  • silencers are characterized by a very simple construction but their effect is insufficient.
  • the noise level achieved by such a silencer at a distance of 10 meters could be reduced only from approximately dB to l25 dB in a known air-blast circuit breaker operating with an operating pressure of 22 atm gauge, so that the threshold of pain was exceeded despite the presence of the silencer.
  • the invention is based on a silencer for high-voltage air-blast circuit breakers, of novel construction featuring an expansion chamber through which the pressurized gas escapes to atmosphere, and is principally characterized in that the wall of the expansion chamber is at least partially constructed as a rubber-elastic membrane provided with pores which open as back pressure is built up within the chamber.
  • the rubber-elastic membrane is disposed within a rigid, perforated vessel in order to limit the expansion of the membrane due to back pressure and thereby prevent possible damage to it due to excess expansion.
  • the silencer according to the invention is based on the principle that the sound power of a free nozzle is proportional to the square of the nozzle cross-section and the eighth power of air velocity. Since the air velocity may be reduced by a subdivision of a larger discharge cross-section into a large number of small crosssections it will be clear that the noise level may be substantially reduced while the first shock wave is absorbed by the rubber-elastic expansion of the membrane.
  • FIG. 1 is a view in central longitudinal section of a circuit breaker of the air blast type with a silencer attached thereto in accordance with the invention, this view showing the contact members and discharge valve in their closed positions, and
  • FIG. 2 is a view similar to FIG. 1 but with the contact members and discharge valve in their open positions.
  • the air pressurized chamber for enclosing the relatively movable, hollow contact members 2 and 3 is indicated at l.
  • a discharge valve which opens when the contact members are disengaged so as to permit discharge of the pressurized air to blast the arc and flow through the interior of contact member 3, is indicated at 4 and is springloaded to its closed position as depicted in FIG. 1.
  • valve 4 when valve 4 is opened as the contact members 2 and 3 disengage, the air flows through contact member 3 and the open valve 4 into an essentially annular expansion chamber 9 which surrounds the springload support mechanism of the discharge valve 4, the ends of this chamber being terminated by rigid flanged end walls 6 and 7.
  • the silencer component in accordance with the invention is constituted by the cylindrical wall portion 5 of the expansion chamber 9 and is made from a rubber-elastic material clamped at its ends to flanges provided on the rigid end walls 6 and 7 of the chamber.
  • the cylindrical rubber-elastic membrane can be made from a material sold by the Dunlop Company under the trade designation Membran .393.
  • the principal characteristic of such material is that it contains a large number of very small pores which open to a significant extent only when the cylindrical membrane 5 is expanded by the back pressure which is built up after the valve 4 has opened.
  • a cylindrical membrane having a length of approximately 40 cm. and a diameter of approximately 35 cm. can have from 50,000 to 200,000 pores.
  • there should be at least one pore per cm of surface and the diameters of the pores, in the expanded state of the membrane are preferably smaller than 1 mm.
  • Jacket 8 which therefore serves to limit expansion of the cylindrical membrane 5, can be constructed from perforated plate material but can also be made from wire or from a grid, in the form of a cage.
  • the rubber-elastic membrane 5 is depicted in its static state, i.e., at rest in a non-stressed position in which the pores are also closed.
  • FIG. 2 which depicts the contact members 2, 3 in their disengaged position and with discharge valve 4 open, pressurized air heated by the arc has already flowed into the expansion chamber 9 from the switch contact chamber 1 and has effected a bulge-like expansion of the rubberelastic membrane 5 in essentially a radial direction which likewise effects opening of the pores therein so that the air can now escape through the pores into the surrounding atmosphere, becoming partly silenced in the process of so doing. Since expansion of the membrane 5 increases with the increase in back pressure, the cross-section of the pores which open as expansion takes place, also depends upon the pressure; Optimum damping of the noise level therefore takes place at all times substantially independently of the pressure.
  • a silencer for a high-voltage circuit breaker of the gas-blast type comprising an expansion chamber into and through which pressurized gas flows from the contact chamber of the circuit breaker as the contacts disengage, the wall of said expansion chamber being at least partially constructed from an expandable rubberelastic material provided with a pore structure wherein the pores open as back pressure builds up within said expansion chamber and release the gas to the atmosphere.
  • a silencer as defined in claim 1 for a high-voltage circuit breaker of the gas-blast type wherein said expansion chamber includes a cylindrical wall portion made from said rubber-elastic material and rigid end walls having flanges to which the opposite ends of said cylindrical wall portionare secured.

Landscapes

  • Circuit Breakers (AREA)
  • Details Of Valves (AREA)
  • Exhaust Silencers (AREA)
  • Reciprocating Pumps (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
US00254963A 1971-06-09 1972-05-19 Silencer for high-voltage gas-blast circuit breaker Expired - Lifetime US3745285A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2128632A DE2128632C3 (de) 1971-06-09 1971-06-09 Schalldämpfer für Hochspannungs-Druckgasschalter

Publications (1)

Publication Number Publication Date
US3745285A true US3745285A (en) 1973-07-10

Family

ID=5810293

Family Applications (1)

Application Number Title Priority Date Filing Date
US00254963A Expired - Lifetime US3745285A (en) 1971-06-09 1972-05-19 Silencer for high-voltage gas-blast circuit breaker

Country Status (9)

Country Link
US (1) US3745285A (enExample)
JP (1) JPS5626928B1 (enExample)
CA (1) CA949108A (enExample)
CH (1) CH536024A (enExample)
DE (1) DE2128632C3 (enExample)
FR (1) FR2140466B1 (enExample)
GB (1) GB1358775A (enExample)
IT (1) IT959782B (enExample)
SE (1) SE369348B (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10794526B2 (en) 2015-01-21 2020-10-06 Deutsches Institut Fur Lebensmitteltechnik E.V. Sound absorber for vacuum grippers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2238657B2 (de) * 1972-08-05 1974-08-08 Brown, Boveri & Cie Ag, 6800 Mannheim Schalldämpfer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10794526B2 (en) 2015-01-21 2020-10-06 Deutsches Institut Fur Lebensmitteltechnik E.V. Sound absorber for vacuum grippers

Also Published As

Publication number Publication date
FR2140466B1 (enExample) 1977-12-23
SE369348B (enExample) 1974-08-19
DE2128632C3 (de) 1973-10-18
CA949108A (en) 1974-06-11
GB1358775A (en) 1974-07-03
DE2128632B2 (de) 1973-04-05
DE2128632A1 (de) 1972-12-14
CH536024A (de) 1973-04-15
IT959782B (it) 1973-11-10
FR2140466A1 (enExample) 1973-01-19
JPS5626928B1 (enExample) 1981-06-22

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