Injector Torch. These low-pressure torches operate on an acetylene pressure of less than 7 Pa (1psi). They were originally designed for use with low-pressure acetylene generators where higher acetylene pressures were not available. The acetylene, passing through relatively large openings, is drawn into the mixer by the action of the high pressure of the oxygen as it passes through a very small orifice in the injector.
Balanced Pressure Torch. These torches utilize acetylene under pressures from 7 to 103 Pa (1 to 15 psi), depending upon the size of the tip. The torch utilizes both oxygen and the fuel gas under equal pressures. In this case, the ports at the entrance to the mixer are equal in area, and under equal pressures deliver equal volumes of oxygen and the fuel gas to the mixer. The flow of gases is not influenced by the mixer, as it is in the injector torch.