Compound Pressure Ranges

Compound pressure ranges include both a positive and negative pressure range in one pressure measurement device.

For example you may want to purge a vessel with a vacuum pressure down to -1 bar gauge to empty it of its contents and then fill the vessel again using a pump which has a positive pressure of 5 bar gauge.

If you fit 2 pressure sensors or gauges to measure the pressure, the vacuum range could be over-pressured and damaged when the +5 bar gauge is applied unless it is protected in some way. Also it is more expensive to purchase two pressure instruments.

So the solution is to combine both pressure ranges into one pressure instrument. So in the above example if a 4 to 20mA output signal is required 4 mA would equal -1 bar gauge and 20 mA would equal +5 bar gauge.

The zero reference of the compound pressure sensor is set at ambient pressure. The sensor is not sealed but has a vent hole that allows inherent compensation for atmospheric pressure changes.