Previously (Part One) we introduced composite materials, reviewed the vacuum bagging method for composite manufacture, and discussed the role vacuum systems play. Here we will take a closer look at these systems, and some of the unique requirements of vacuum equipment for composite manufacture.
The most common vacuum pump used in industrial scale composite curing units is the rotary vane pump. A rotary vane pump is considered a wet, positive displacement pump. Wet, because the air being pumped is exposed to oil used as a lubricant and to help provide the seal. Positive displacement refers to the fact that the pump works by mechanically trapping a volume of gas and moving it through the pump, creating a low pressure on the inlet side.