GB940863A - Improvements in or relating to tubes - Google Patents

Abstract

940,863. Rolling tubes. BABCOCK & WILCOX Ltd. April 16, 1962 [April 17, 1961; Sept. 11, 1961; Sept. 22, 1961], No. 14599/62. Heading B3M. [Also in Divisions F2 and F4] A method of forming a lenticular tube 1 (see Division F2) comprises passing a tube 1a through successive pairs of peripherally grooved rolls 6, 7, 8, the sections in which the wall thickness is greater passing generally in the regions of the rolls where the grooves have their least depth. The tube la may according to a further method, be passed through pairs of grooved rolls and die surfaces which may be fixed or peripheral surfaces of rolls, the rolls and die surfaces being in the same plane (Fig. 9, not shown). The two longitudinal projections of the circular crosssection tube 1a co-operate with guides of the roll assembly. The tube may be heated locally at the portion of increasing wall thickness, this heating being effected by applying heat to only the required area or otherwise to the whole tube and subsequently cooling the appropriate sections. A lenticular tube of uniform wall thickness may be provided with a wall of varying thickness by passing a die through its bore. If the grooves of the rolls are deep distortion of the tube may occur. The distortion, however, may be eliminated by forming the grooves as the collective peripheries of a plurality of independently rotating discs.