Cutting heavy steel plate etc. is carried out by jets of gas, e.g. oxygen, emitted from the periphery of a rotating disc. The jets are evenly spaced around the periphery of the disc, and each makes an angle of less than 90 deg. with the tangent to the disc, at the point where it emerges. Contrary to previous practice, the disc rotates in a sense opposite to the tangential components of the jets. Alternatively, cutting with the side of the disc where the jets point downwards, it rotates so that the jets cross the piece to be cut from bottom to top.
Reversing the rotation of the cutting disc gives a narrower cleaner cut than produced by the known technique, partic. at the underside of the metal. Less metal is wasted, and because the molten oxide can flow freely away, oxygen is only required to support combustion, and not to blow oxide clear. The method is claimed to show useful economics, and to work satisfactorily where a number of pieces of metal have to be cut in succession.
A distributor disc (1) has gas jets (a1-a7, etc.) evenly distributed around the periphery (2). Each makes an angle (Beta), less than 90 deg., with the tangent to the periphery where it emerges. They are supplied with gas through radial channels (c), a distribution control (t) ensuring that at any time a gp. of jets (a1 to a7 as drawn) receives gas. Arrow (F2) shows the direction in which the disc advances to cut into steel plate (3). Arrow (F1) shows the direction of rotation of the disc in previous practice. Under this invention it rotates in the opposite direction. As drawn the jets cross the metal being cut from bottom (5) to top (4). An auxiliary jet (b) may be used to heat the metal locally, prior to starting to cut.
