Plasma torch provided with a ceramic protective cap
AssigneesLa Soudure Autogene Francaise, L'Air Liquide, Societe Anonyme a Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsRegis Augeraud, Michel Delzenne
Life of this patent
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Abstract
Protective cap for a plasma arc working torch, includes a cap body (7) having an opening (17) for the passage of plasma gas, the cap body (7) being made of at least one material of ceramic type. The ceramic is a silicon nitride or an aluminum silicate. Preferably, the ceramic cap body (7) is clad with boron nitride deposited on the external surface of the cap body, the thickness of the cladding of boron nitride being less than 3 mm. Torch provided with such a cap and its use in a steel plate plasma cutting operation.
Claims19
Protective cap for a plasma arc working torch, comprising a cap body (7) comprising an opening (17) for passage of plasma gas, at least one portion of said cap body (7) being comprised of at least one ceramic type material, characterized in that said ceramic is aluminum silicate formed of SiO2, Al2O3 and one or several additional constituents selected from TiO2, Fe2O3, CaO, MgO, K2O, Na2O and P2O5, in the following proportions:
- at least 60% by weight of SiO2, at least 25% by weight of Al2O3 and the rest being essentially one or several additional constituents selected from TiO2, Fe2O3, CaO, MgO, K2O, Na2O and P2O5, preferably the ceramic is aluminum silicate formed of 60 to 80% by weight SiO2, from 25 to 35% by weight of Al2O3 and the rest (up to about 100% by weight) one or several additional constituents selected from TiO2, Fe2O3, CaO, MgO, K2O, Na2O and P2O5.
Protective cap for a plasma arc working torch comprising a cap body (7) comprising an opening (17) for passage of plasma gas, at least one portion of said cap body (7) being comprised of at least one material of ceramic type, characterized in that said ceramic is silicon nitride having one or several of the following properties:
- a density of 2 to 4 kg/dm3,
- a thermal shock resistance greater than or equal to 600° C.,
- a volumetric resistivity of at least 1010Ω·cm,
- a coefficient of thermal expansion less than 6.10−6/° C.,
- a flexure resistance at 20° C. of at least 200 MPa,
- a compressive resistance of at least 650 MPa.
Protective cap for a plasma arc working torch, comprising a cap body (7) comprising an opening (17) for passage of plasma gas, at least one portion of said cap body (7) being comprised of at least one ceramic type material, characterized in that said ceramic is aluminum silicate, wherein said ceramic cap body (7) is at least partially clad with boron nitride deposited on the external surface of the ceramic cap body.
Dependencies are inferred from the claim text.