Components of oxy-acetylene outfit in gas welding

By using the proper tips, rods and fluxes, almost any metal can be welded, heated or cut using the gas welding process. There are many components that make up the oxy-acetylene outfit in gas welding such as cylinders, regulators, hoses etc. The following is an outfit listing each component with a brief description of each.

Cylinders. Oxygen and acetylene are stored under pressure in steel cylinders. All cylinders have valves and are fitted with a screw on steel cap that protects the cylinder valve when the cylinder is not in use. Acetylene cylinders contain a porous filler material which is wetted with acetone that allows the acetylene to safely be contained in the cylinder. Acetylene should never be used at a pressure that exceeds 15 psi as it becomes highly unstable which, depending on the condition, could cause it to decompose and explode.

Regulators. With the pressure in a full acetylene cylinder at 250 psi and a full oxygen cylinder at 2200 psi, a way is needed to lower these cylinder pressures to desired working pressures for use in the torch. This is accomplished by using an adjustable pressure reducing regulator. Basically, regulators work by admitting the high cylinder pressure through a valve which is operated by a flexible diaphragm. Turning the regulator adjusting knob or screw in or out causes a spring in the regulator to operate the diaphragm which opens or closes a valve in the regulator. This in turn regulates the outlet pressure and flow. There are two general types of regulators, single stage and two stage. Both perform the same function but the two stage regulator supplies a more constant pressure as the cylinder pressure falls by compensating for any drop in cylinder pressure better than the single stage unit.

Welding hoses. The cylinder regulators and torch are usually connected together by double line rubber hoses. The oxygen line is green, the fuel line is red. All hoses should be marked as to their service level (light, standard or heavy). Single line hoses are limited to a working pressure of 200 psi.

Check valves. For combustion to occur, fuel and oxygen have to mix. This should only happen in the torch mixer or the torch tip. Sometimes, due to improper operation, fuel and oxygen could feed back into the hoses and cause combustion in the hoses or regulators. Check valves when installed between the hoses and torch prevent this back flow as they close if a reverse flow starts.

Torches and welding tips. The torch assembly consists of the handle, oxygen and fuel gas valves and mixing chamber. Oxygen and fuel gas flow through tubes inside the handle which blend in the mixing chamber or tip. It is at the tip that the mixed gases are ignited. There are two basic mixer types, the equal or medium pressure type (also known as balance or positive pressure type) and the injector type. Oxygen and fuel gas enter the torch at almost equal pressures. The welding tip is mounted on the end of the torch handle and through it the oxygen and fuel gas mixture feed the flame. Tips are available in a variety of shapes and sizes to fit most any welding job and are identified by number. The larger the number, the larger the hole in the tip and the thicker the metal that can be welded.