Elias hit the green button. The old diesel engine roared to life, a cloud of white smoke puffing out. The vacuum gauge on the deaerator began a slow, steady fall.
For viscous flow (rough vacuum), short, large-diameter pipes are critical. vacuum pump capacity calculation xls
But with :
If you prefer not to build from scratch, several manufacturers and technical sites provide downloadable XLS tools: Elias hit the green button