A digital absolute pressure gauge is now available in the USA and Canada through German Advanced Composites`online shop
If the purpose of the vacuum infusion process is to produce high-quality parts, we strive to achieve an absolute in-bag pressure in the range of 10mbar (0.295inHG) to 20mbar (0.59inHG) above the absolute zero of pressure at the pump. If we want to control that a bag has been evacuated to this degree of vacuum, the gauge used to measure this value needs to be accurate in this region. A conventional analog dial gauge, usually mounted on the vacuum pump or resin catch pot, measures the pressure difference below the atmospheric pressure (manometer) and is affected through an inaccuracies of at least ±50 mbar (1.50inHG) due to changing environmental conditions and the poor accuracy of the mechanism within the gauge. It is apparent that such a gauge is not an appropriate instrument for measuring an in-bag vacuum of 10 to 20 mbar.
A precise digital absolute pressure gauge (barometer) solves this problem. The reading is the pressure above the absolute zero of pressure (or perfect vacuum) thus it is uneffected by weather or altitude. It responds to pressure changes with a resolution of 1mbar down to absolute zero in an instant which does not only save time with setting up the vacuum system and finding leaks. It is also a reliable performance indicator for the quality of the infusion process because for the first time you know exactly what is happening inside the vacuum bag even in the low pressure range a high-quality infusion process usually takes place.