GB1248570A - Nozzles for cutting torches - Google Patents

Abstract

1,248,570. Burners. BRITISH OXYGEN CO., Ltd. 22 Nov., 1968 [6 Dec., 1967], No. 55581/67. Heading F4T. In a gas-fuelled cutting nozzle 2, the central longitudinal passage 16 for high purity oxygen has at its outlet end a cylindrical recess 22, and an insert 26 with a central passage 28 contiguous with passage 16, is secured in the recess 22 so that its outer surface defines therewith an annular passage 32 extending over an appreciable length of the insert, and several radially extending bleed holes 34 connect passages 32 and 28. The cross-sectional areas of the holes 34 are less than that of the passage 28, and the main oxygen stream is progressively accelerated by means of a restricted portion 20 of passage 16 and a frusto conical portion 30 of passage 32 so that an effectively annular screen of low velocity oxygen is formed about a high velocity cutting oxygen stream. A holder (not shown) fits over the end of the nozzle remote from the insert and cooperates with frusto-conical surfaces 4, 6 and 8 to define two chambers 10 and 12 for fuel gas e.g. acetylene, and oxygen, respectively, and the two gases are fed into and mixed within a circular series of preheat passages 18 or an annular passage arranged concentrically about the recess 22 to give an outer annular preheat flame. In a modification the insert has longitudinal grooves provided at its outlet end to define with the recess a series of passages for the screening oxygen, each connected to the central passage 28 via a bleed hole.