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The compressed air supply of leaktest and flow test systems

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Since the supply air at the same time the test medium is more or less all testers respond to variations in pressure in the compressed air supply. This can for example be caused by large pneumatic cylinders are moved during the test phase. This can lead to larger scatter of test results.

May also prevent dirt, moisture or oil get into the test circuit. Where this can not be guaranteed, must be given to appropriate countermeasures.

Need to eliminate all these influences some rules:

  • The air control (for cylinder etc.) and the test air (for the test equipment) should generally be at least through separate maintenance unit with pressure regulator and a fine filter (10 microns) separated
  • The test air must be using at least water and oil separator and fine filter (10 microns) prepared before the devices
  • Eventually, the use of a pressure accumulator with a check valve for compressed air supply required
  • Possibly the use of an air dryer for the necessary test air

Contamination can also come from the specimen. Should this danger exist, must also be created here by appropriate counter-measures (test air filter, exhausting box etc.) remedy.


The compressed air supply should follow for all test systems in DIN ISO8573-1, the following classification:

Particle class 2 (<= 5µm)
Water class 3 (pressure dew point -20°C)
Oil class 2 (<= 0,1mg/m3)

For pollution by liquids or solid particles in the pneumatic circuits and the resulting damage to the pneumatic components and damage the pneumatic components by applying an external pressure on the test item connection no warranty or liability is accepted. This also applies for any consequential damages in test or test parts.