GB515251A - Improved process and apparatus for the heat treatment of steel rails - Google Patents

Abstract

515,251. Heat-treating rails. SANDBERG, C. P., and SANDBERG, O. F. A. April 12, 1938, No. 11191. [Class 72] In the heat treatment of railway or tramway rails by an accelerated cooling from a temperature above the control range by jets of cooling medium, a relative travelling movement is provided between the rail and the jets and also a grading of the rate of and degree of the cooling of the rail from the first to the last jet encountered is attained either by providing that the amount of cooling medium delivered by the successive jets or successive sets of jets diminishes or the spacing of the jets or the temperature of the cooling medium increases from the first to the last jet. The amount and temperature of the cooling medium delivered by any jet is constant during the treatment of any given rail or batch of rails. To equalise the temperature differences in the rail so that the rail is at a desired temperature before it is cooled, the rail is either placed in a heat-insulated chamber one end of which is close to the cooling jets or in a heat-insulated container, the insulation varying progressively along its length or is subjected to mild accelerated cooling the degree of which varies progressively along the length of rail so that each part of the rail as it comes in contact with the jets, is substantially at the desired temperature. The rail A is fed by rollers B<1>, B<2> to E<1> E<2> in the direction of the arrow R on to supporting rollers C<1>, C<2>, C<3> and is guided by rollers D<1>, D<2>, D<3>, D<4> in the form of cups which catch the water flowing off the head of the rail. The atomising nozzles J<1>, J<2> are fed by water mains I<1>, I<2>, the pressure in the main I<1> being greater than that in the main I<2>, air from a low pressure main H being supplied by a fan to the apertures P in the jets J<1> &c. The structure carrying the mains &c. is supported on columns N<1>, N<2> the height of which may be varied. The nozzles may be arranged to project the cooling medium vertically on the top of the rail head or may be in two staggered rows or both sets together. The rail may be fed head downwards above a row of nozzles directed upwards. Water flowing off between the rollers may be caught by catch plates K<1>, K<2>. After passing through the rollers E<1>, E<2> the rail is given a counter-camber by the rollers M<1>, M<2>. Specification 406,029 is referred to.