The check valve is used to prevent the backflow of oxygen into the acetylene gas pipe or the backflow of acetylene into the oxygen gas pipe. The check valve is marked with the direction of gas flow.
Unlike flashback prevention safety catches ( firebackers ), flashbacks provide protection in the event of a flashback. It has two main functions. In addition to preventing gas backflow like a check valve, it can also prevent backfire by cooling the flame. The flashback prevention safety switch is usually attached with a pressure or temperature shut-off valve, which is activated by different principles to prevent the flashback from spreading into the cylinder from the blow pipe and the gas supply pipe.