Method for producing heat exchanger tubes, which consist of half-tubes or complete tubes and which are provided for recuperative exhaust gas heat exchanger
OwnerLudwig Steinhauserinventor
Life of this patent
Estimating the term…
Abstract
In a process for the production of half-tubes or tubes of a recuperative waste gas heat exchanger using a precision casting process, the half-tubes or tubes consisting of a high-temperature-resistant metallic material have a plurality of elliptical openings passing through their surface.
Claims18
1-9. (canceled)
A process for producing one of (a) half-tubes and (b) a tube of a metallic, high-temperature-resistant material with a plurality of openings passing through a surface of the one of (a) the half-tubes and (b) the tube for fabricating heat-exchanger tubes for a recuperative waste gas heat exchanger, comprising:
- forming a model, destroyable by heat, of each of the one of (a) the half-tubes and (b) the tube;
- forming a mold shell by finishing with a conventional gate system and immersion of the model in a ceramic coating composition and sanding with a cast shell ceramic material, alternating in several cycles;
- melting-out of the model from the mold shell;
- hardening the mold shell by firing;
- producing a melt from the metallic, high-temperature-resistant material;
- casting the melt in the mold shell one of (a) by applying a vacuum and (b) under excess pressure of an inert gas;
- removing, after solidification of the melt, the one of (a) the half-tubes and (b) the tube from the mold by destroying the mold shell;
- cleaning and trimming the one of (a) the half-tubes and (b) the tube and removing a sprue;
- and
- post-treating, as necessary, the opening passing through the surface of the one of (a) the half-tubes and (b) the tube by one of (a) spark erosion and (b) blasting with an abrasive blasting agent.
A half-tube formed of a metallic, high-temperature-resistant material with a plurality of openings passing through a surface thereof for fabricating heat-exchanger tubes for a recuperative waste gas heat exchanger, comprising:
- forming a model, destroyable by heat, of the half-tube;
- forming a mold shell by finishing with a conventional gate system and immersion of the model in a ceramic coating composition and sanding with a cast shell ceramic material, alternating in several cycles;
- melting-out of the model from the mold shell;
- hardening the mold shell by firing;
- producing a melt from the metallic, high-temperature-resistant material;
- casting the melt in the mold shell one of (a) by applying a vacuum and (b) under excess pressure of an inert gas;
- removing, after solidification of the melt, half-tube from the mold by destroying the mold shell;
- cleaning and trimming the half-tube and removing a sprue;
- post-treating, as necessary, the opening passing through the surface of the half-tube by one of (a) spark erosion and (b) blasting with an abrasive blasting agent;
- wherein the openings are elliptical in shape.
A tube formed of a metallic, high-temperature-resistant material with a plurality of openings passing through a surface thereof for fabricating heat-exchanger tubes for a recuperative waste gas heat exchanger, comprising:
- forming a model, destroyable by heat, of the tube;
- forming a mold shell by finishing with a conventional gate system and immersion of the model in a ceramic coating composition and sanding with a cast shell ceramic material, alternating in several cycles;
- melting-out of the model from the mold shell;
- hardening the mold shell by firing;
- producing a melt from the metallic, high-temperature-resistant material;
- casting the melt in the mold shell one of (a) by applying a vacuum and (b) under excess pressure of an inert gas;
- removing, after solidification of the melt, tube from the mold by destroying the mold shell;
- cleaning and trimming the tube and removing a sprue;
- post-treating, as necessary, the opening passing through the surface of the tube by one of (a) spark erosion and (b) blasting with an abrasive blasting agent;
- wherein the openings are elliptical in shape.
Dependencies are inferred from the claim text.