Vacuum

Vacuum is the range of pressure which lies between absolute zero pressure and atmospheric pressure.

Vacuum pressures in the range of a few millibars up to atmospheric pressure are easily measured by diaphragm based pressure measurement instrumentation. In this range of partial vacuum pressures it is common to measure the vacuum using either a negative gauge reference or an absolute reference pressure sensing device. The choice of a negative gauge or an absolute reference will depend on whether you are interested in measuring the pressure compared to atmospheric pressure or to a perfect vacuum.

High vacuum pressures are very close to zero absolute pressure and much harder to measure with diaphragm type instrumentation. At high vacuum pressures it is necessary to use different sensor technology which is based on ionisation or thermal conductivity measurement principles.

Vacuum pressures are generated in many applications within the research and industrial sectors which include gas/vapour removal, leak testing, pick-up tools, sterilization, semiconductor processing and altitude simulation.