Various Welding Equipment used in Gas Welding

 The most commonly used equipment for gas welding are :

 Welding Torch : 

 This is a tool for mixing oxygen and acetylene in correct proportion and burning the mixture at the end of   a tip. These are available commercially in two general types :

(1) Equal Pressure 

(2) Injector - Type 

The medium - or equal pressure welding torch is the more common of the two types of oxy-acetylene torches. The mixing chamber in the equal pressure torch allows both of the gases to flow together in equal amounts.

Welding Tip :

It is that portion of the welding apparatus through which the gases pass just prior to their ignition and burning. There is a great variety of  interchangeable welding tips differing in size , shape and construction. The tip sizes are governed by the diameter of the opening. The diameter of the tip opening used for welding depends upon the type of  metal to be welded, such as whether it is stainless steel, iron or brass, and the thickness of  the metal to be welded. 

Pressure Regulator :

The functions of a pressure regulator is to reduce the cylinder pressure to the required working pressure and also to produce a steady flow of gas (gas volumetric rate) regardless of the pressure variations at the source.

Regulators may be classified into four main types :

1.) The single - stage nozzle, type.

2.) The single - stage stem, type.

3.) The two - stage type.

4.) The high capacity high pressure line type. 

Regulators for different gases are basically the same, except the pressure that they control differ vastly.

Hose and Hose Fittings :

The hose of the welding torches should be strong, durable, nonporous, and light. The most common method of piping both oxygen and acetylene gas is the reinforced rubber hose, which comes in black, green and red. Green is the standard color of the oxygen hose , red for acetylene and black hose for other industrially available welding gases. Special hose fittings, or connections, are provided for attachment to the torch and pressure regulations. 

Goggles, gloves and spark lighters : Goggles fitted with colored lenses are provided to protect the eyes from harmful heat and ultraviolet and infrared rays. 

Gloves are used to protect the hands from any injury.

Spark-lighter provides a convenient and instant means for lighting the welding torch.

In addition to the above requirements , welding rods and fluxes are also employed.

Gas Cylinders :

Oxygen gas in cylinders are usually charged with about 40 liters of  oxygen at a pressure of about 154 Kg-f / cm2 (15400 k N/m2) at 21*C. Outside temperature changes will , of course , change the pressure within the cylinder since the volume remains constant. A full cylinder has the weight of about 80 kg. To provide against dangerously excessive pressure, such as could occur if  the cylinders were exposed to fire , every valve has a safety device to release the oxygen before there in any danger of rupturing the cylinders. Fragile discs and fusible plugs are usually provided in the cylinders valves in case it is subjected to danger. 

Acetylene Gas can be manufactured either by water-to-carbide method (high pressure) or the carbide-to-water method. There are two types of  carbide-to-water generators : Low pressure and Medium pressure. These generators operate on ratio of 4.5 liters of water to 0.45 kg of carbide. The low pressure generator produces less than 0.07 kgf / cm2 (7 kN / m2). and the medium pressure acetylene generator produces from 0.07 to about 1 kgf/cm2 ( 7 to 100 kN /m2).