Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/38—Torches, e.g. for brazing or heating
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01M—CATCHING, TRAPPING OR SCARING OF ANIMALS; APPARATUS FOR THE DESTRUCTION OF NOXIOUS ANIMALS OR NOXIOUS PLANTS
  • A01M15/00—Flame-throwers specially adapted for purposes covered by this subclass
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details
  • F23D14/48—Nozzles
  • F23D14/52—Nozzles for torches; for blow-pipes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23Q—IGNITION; EXTINGUISHING-DEVICES
  • F23Q3/00—Igniters using electrically-produced sparks
  • F23Q3/002—Igniters using electrically-produced sparks using piezoelectric elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2207/00—Ignition devices associated with burner

Definitions

• the present invention relates generally to a gas appliance, comprising a burner, the combustion heat of which is consumed for various practical purposes, such as welding, cooking, etc.
• control member for a flow of combustible gas namely a regulator
• a burner comprising a member for admixing air which oxidises the flow of controlled combustible gas, a member for combustion of the air / combustible gas mixture, and a metal conduit for transferring said mixture, connecting the outlet of the control member, and 1 entry of the combustion member;
• a piezoelectric ignition member of said mixture comprising, on one side an electrode, insulated with respect to the metal conduit, and disposed at a distance from the latter, and on the other side said conduit connected to ground; as well as a piezoelectric generator connected to ground and to the electrode.
• the electrode constitutes a part or a component whose positioning requires precise positioning, since 1 beyond the breakdown distance, no ignition of the mixture to be burned takes place. This requires, on the one hand one or more precision machined parts, and on the other hand a controlled mounting operation.
• the present invention relates to a piezoelectric ignition member, particularly simple in its constitution and in its arrangement, without compromising
• the electrode belongs to and is disposed at the end of a semi-rigid electric wire, disposed inside the transfer duct, formed to provide, on the one hand, a bent part braced with the inside said conduit, and on the other hand an end branch moving away from the transfer conduit to provide between a stripped end and said conduit a predetermined breakdown distance.
• the transfer duct comprises at least two tubes, one internal at a proximal end of which the admixture member is arranged, and the other external at a distal end which is disposed the combustion member,
• the electrode of the ignition member is arranged inside and at the distal end of the internal tube.
• the length of the external tube is adapted to the maximum deflagration stroke, when igniting the burner, for transporting a combustion front from the proximal end of the external tube to the combustion member, and lighting the latter.
• FIG. 1 shows, in perspective, the functional part of a gas appliance according to the invention, to the exclusion of its other organs or components, including shell and chassis;
• FIG. 1 shows a sectional view of the burner belonging to the gas appliance according to Figure 1.
• a source independent of the appliance for example a gas tank, or from a container, for single use or not, for example cartridge connected to the gas appliance;
• a burner 3 comprising or assembling itself: * a member 4 for admixing primary air, or oxidizing, to the flow of controlled combustible gas, constituted as known per se, and better represented in FIG. 2, by an injector 12 and an opening 13 for introducing combustion air driven by the jet of combustible gas ejected by the injector 12;
• this transfer duct 6 comprises at least two tubes, one internal 6a, at a proximal end of which is disposed the admixtion member 4, and the other external 6b at a distal end of which is disposed the combustion member 5;
• a piezoelectric ignition member 7 of the burner mixture itself comprising:
• an electrode 8 disposed at a distance from the metal conduit 6, itself grounded, and more precisely inside and at the distal end of the internal tube 6a; * and a piezoelectric generator 9 connected to ground and to the electrode 8.
• the apparatus also comprises a telescopic member 10 for adjusting the length of the transfer duct 6, by sliding the external tube 6b on the internal tube 6a.
• the length of the external tube 6b is adapted to the maximum deflagration stroke, when the burner 3 is ignited, to transport a combustion front from the proximal end of the external tube 6b to the combustion member 5, and light the latter.
• the diameter of the internal 6a and external 6b tubes is less than a limit diameter below which the speed of passage of the mixture to be burned is greater than the speed of deflagration, when the burner 3 is ignited.
• the electrode 8 belongs to and is arranged at the end of a semi-rigid electric wire 11 itself comprising a heat-resistant sheath, for example made of silicone.
• This electric wire 11 is partly arranged inside the internal tube 6a, and is formed or preformed to provide: - On the one hand a bent portion 11a braced within one of the inner tube 6a; this bent part comprises three bends 11b, lie, lld, respectively and successively opposite, together determining two end points of support 11b and lld on one side, and an intermediate point of support links on the other side of the inner tube 6a ;
• an end branch 11b departing from the inner tube 6a to provide between its stripped end 8a and the inner tube 6a, a predetermined breakdown distance.
• the predetermined plating distance is between 4 and 6 mm and is preferably equal to 5 mm. Below 4 mm, the electric spark is not strong enough to ignite the gas, and above 6 mm, this distance is too great to obtain an electric spark.
• the arrangement described above is particularly advantageous in that it allows, with simple means, to fix a critical and precise distance between the electrode 8 and the internal tube 6a.
• the present invention can be applied to devices other than a thermal weeder, for example to devices of the torch type.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Insects & Arthropods (AREA)
• Pest Control & Pesticides (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Environmental Sciences (AREA)
• Catching Or Destruction (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9508517

Family Applications (1)

Country Status (4)

Families Citing this family (11)

Family Cites Families (7)

• 1997
  • 1997-06-23 FR FR9708068A patent/FR2764969B1/fr not_active Expired - Lifetime
• 1998
  • 1998-06-15 EP EP98924503A patent/EP0991897A1/de not_active Withdrawn
  • 1998-06-15 WO PCT/IB1998/000935 patent/WO1998059199A1/fr not_active Ceased
  • 1998-06-15 US US09/446,659 patent/US6190161B1/en not_active Expired - Fee Related

Non-Patent Citations (1)

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