| 摘要 |
1305291 Brazing AEROQUIP AG 24 April 1970 [14 May 1969] 19885/70 Heading B3R [Also in Division G1] In a method of brazing in which the temperature of the workpiece rises on the application of heat to a first peak at which the braze material begins to melt and flow, whereupon the temperature falls off somewhat before rising again to a desired brazing temperature below the previous peak, temperature sensing and control means are used to terminate the application of heat only in response to the second detection of the desired brazing temperature. Brazing apparatus for brazing together two workpieces, e.g. tubes 26, 28 includes a light tube or fibre-optic means 50 placed so as to sense changes in emission of light from the joint area upon heating and to transmit the light to a photo-electric cell 56 arranged to control the termination of heating at a preselected level of emission of light, i.e. at a preselected temperature. The brazing head 10 includes two jaws 20, 22 adapted to surround a sleeve member 30 which surrounds the workpieces 26, 28. Annular cavities 32, 34 in the sleeve 30 are provided to hold brazing material and an electrical heating coil (not shown) surrounds the cavity 38 in which the workpieces are held. The electrical control circuitry is arranged to ignore the first peak in temperature (the melting point of the braze material) and to cut off the current only when the temperature rises again to the preselected brazing temperature. |
