(a) The Universal metal cutting blowpipe is shown in Fig. 49, the sections being shown broken in the shank to enable views to be given on a larger scale.

The principle on which the cutting blowpipe heats is similar to that of the Company's Universal injector welding blowpipe. The oxygen under suitable pressure is made to draw the combustible gas (acetylene) into the blowpipe and then deliver both gases well mixed and under sufficient pressure through the nozzle D.

In the body f there are passages k and j, through which the supply of acetylene and oxygen required for heating respectively pass, and these passages are fitted with a separate tap and valve H and R, by means of which the proportions of the gases for heating purposes can be regulated. The body is also provided with screwed socket projections at the back into which the connector O for the main supply of oxygen and the tap H for the supply and control of acetylene are fixed, the gases being led to the blowpipe through rubber or other suitable tubing.

The combustible gas is conveyed through the passage k to the chamber p, while the oxygen is supplied to the underside of the valves R and by by each of which it is regulated and allowed to travel by the separate passages j and r through the pipes s and t to the nozzles D and C respectively. It will be seen on reference to the illustrations that the valve through which the supply of oxygen passes to the cutting nozzle is capable of double control, for it can be operated by means of the thumb-screw G, which acts upon the valve spindle ft, or the thumbscrew G can be screwed back in the handle lever P, after which the valve-spindle can be controlled by the lever. In this way great nicety of adjustment can be obtained.

The valve is held open by the spring e, which is contained in the body part f. At the end of the spring there is a washer g which presses on the shoulder h formed on the extended part of the valve spindle. A cap, which is screwed into a recess formed in the body f9 holds the spring in position. The upper part of the valve-spindle passes through a stuffing-box, as shown, and projects sufficiently for the thumb-screw G to act upon it. On the body part there is a fork, in which, by means of the pin i, the lever P is centred.

On the inside of the body there is a recess which receives the junction-piece v, in which are openings communicating with the passages j, k and r, as shown. The openings which communicate with j and r are prolonged through v, and into this prolongation are fitted the pipes s and t. The opening corresponding with the passage k is carried through the outer side of the junction-piece, and so communicates with the chamber p, which is in communication with the tube w, It will thus be quite clear that while the separate supplies of oxygen are conveyed through the pipes s and I for heating and cutting respectively, the acetylene is at the same time conveyed outside these pipes in-ide the tube w, .o the elbow-piece a, where, beyond the injector nozzle z, it meets the oxygen supply for heating, by which it has been drawn forward through the passages x and At the expansion orifice b1, which communicates with the annular space between the nozzles D and C, the gases are mixed. The oxygen used for cutting passes through the pipe f, which is also fitted to the elbow piece a. By this means there is a separate supply of oxygen obtained for cutting, which is capable of adjustment and control by means of the thumb-screw G or the lever P as already explained.