| 摘要 |
570,900. Brazing radiators &c. CLIFFORD MANUFACTURING CO. Nov. 10, 1943, No. 18684. Convention date, Oct. 7, 1942. [Classes 83 (ii) and 83 (iv)] Thin-walled, tubular heat-exchangers for radiators, oil coolers, intercoolers, &c., are made by inserting the tubes 10 of uniform diameter in closely-spaced holes in headers 12, 14, applying limited amounts of brazing material or hard solder 32 in finely-divided or sprayed form to the parts, applying flux in small particles 34 above the brazing material and heating the assembly in a heated atmosphere to a temperature sufficient to melt the brazing &c. material. ' The parts may thus be brazed instead of soft soldered without damaging the tubes by the dissolution in a large mass of brazing material &c. The tubes may be of copper, brass, aluminium or other non-ferrous metal or alloy and the headers of copper, brass, aluminium or alloy thereof or the alloy sold under the Registered Trade Mark " Monel," headers of copper, brass or Monel metal being preferably used with copper tubes and headers of aluminium or alloy thereof with aluminium tubes. The assembly after brazing is placed in a tank or casing which is secured to the header flanges by torch brazing or line welding. The ends of the tubes are shaped to hexagonal form, either before or after the headers are secured in the casing. One or more intermediate headers 18 may be used for supporting long tubes or to serve as baffles. The tubes may be of the order of 0.005" to 0.007" in thickness. The tubes may be inserted in the header 10 and arranged vertically and loose granules 32 of brazing material of a size varying from a fine powder to 0.025", poured into the top of the header and flux 34 in fine particles and preferably of the same density, uniformly distributed over the brazing material. The assembly is preferably shaken to distribute the material uniformly, and is then placed in an oven in which the brazing material is melted by circulation of hot air therethrough. After one header is brazed the assembly is turned over and the other ,end treated in a similar manner, the downward currents of hot air or gas melting the brazing material at the top of the assembly without melting the brazing material at the other end. In a modification, the parts may be arranged as in Fig. 2 and the brazing material sprayed on to the surface by a metal spraying-gun and then covered with flux and heated as in the first method. U.S.A. Specification 2,298,996 is referred to. |
