Gas Welding Machine Parts and Functions
[oxy-acetylene]
The complete set of gas welding equipment consists of oxygen and fuel gas stored in individual cylinders, two pressure regulators and two pressure hoses (one for each cylinder), and a welding torch. The two hoses connect the two cylinders to the welding torch. The welding torch can also be used for soldering and brazing by changing the nozzles. The complete set of equipment is arranged on a trolley for ease of movement and portability.
Different parts of the gas welding equipment are:
Oxygen cylinder (green color) :– This cylinder contains the oxygen stored under pressure which is required for combustion. The oxygen cylinder is made of thick gauge steel to withstand the pressure. The cylinder has a regulator with two pressure gauges. The regulator is connected to the gas torch through a good-quality pressure hose.
Fuel gas cylinder (red color) :- The fuel gas cylinder is made of thick gauge steel and is completely sealed to prevent leakage of the compressed fuel gas stored inside the cylinder. This cylinder has a regulator with two pressure gauges. The regulator is connected to the gas torch through a good-quality pressure hose.
Control valves :– Both the oxygen and the fuel gas cylinders have their own control valves. Control valves control the amount of gas going out of the cylinder, and using the control valves; you can control the ratio of the fuel gas and oxygen mixture.
Pressure gauges :– There are two pressure gauges on each cylinder (oxygen and acetylene). One pressure gauge indicates the pressure of the gas inside the cylinder, and the other pressure gauge indicates the pressure of the gas in the hose.
Hoses connecting the gas welding torch with the gas cylinders – The hoses are of good quality and can withstand high pressure. The hose connecting the oxygen cylinder and the welding torch is green, and that connecting the acetylene cylinder and the welding torch is red.
Mixer chamber :– The mixer chamber is a part of the gas welding torch, and this is where the fuel gas and oxygen get mixed together before flowing out through the nozzle of the gas welding torch. The hoses from the fuel and oxygen cylinders connect to the mixer chamber. The oxygen and the acetylene enter the mixing chamber through the hoses, and there is one needle valve each for the entry of oxygen and acetylene into the mixing chamber. The valves are used for fine-tuning the ratio of fuel gas and oxygen.
Gas welding torch :– A gas welding torch is where the fuel gas and oxygen are mixed before combustion. The welding torch has the mixer chamber at one end and a nozzle at the other end.
The acetylene and oxygen mixture exit from the nozzle to ignite (the welder uses a lighter). There will be a set of nozzles that can be fitted on the gas welding torch for different applications. The gas welding torch is designed to accommodate different sizes of copper nozzles (swan neck type) that allow the proper intensity of the flame to be used. There is a relationship between the thickness of the metal to be welded, nozzle size, and the welding speed.
Flame traps :– Typical flame traps are fitted between the hoses and the regulator on the cylinder. The flame trap is a safety device and prevents a flame generated by a ‘flashback’ from reaching the gas cylinder. The major causes of flashbacks are overheating of the gas welding torch or failure to purge the hoses.
Color code :– The hoses and gas cylinders used in gas welding are color-coded for easy identification. The acetylene cylinder and the hose connecting the acetylene cylinder and the welding torch are red. Similarly, the color of the oxygen cylinder and the hose connecting the oxygen cylinder and the welding torch are green.