Pressure intensifiers increase the pressure in a medium, for example, for laboratory tests of valve, pipes and hoses. A pressure of 7 bar can be amplified in a single stage to 200 bar or up to 1700 bar in multi-staged equipment. The pressure intensifier is only available for very small flows. When the high pressure chamber is filled, the low pressure piston is lifted. When the propellant flows in, the piston is pressed downwards and forces the medium out under high pressure. The intensifier can work in a cycling process, up until a preset pressure level. All inert gases can be compressed in this way. Air can also be compressed in a pressure intensifier, but must be completely oil-free to avoid selfignition.