COuld be used as a clamping system for light duty parts in a machining center.
In a plant where vehicles are manufactured, every single fluid which goes into the car (brake, radiator, AC refrigerant, hyd power steering) save the windshield washer fluid is done by first evacuating the system as far as the pump can take it. For example the radiator hoses will be sucked apparently flat from the outside. The pump is isolated from the evacuated system and pressure-decay testing starts, to see if the evacuated system is sealed or is leaking. If sealed, the fluid is then introduced, it flows rapidly and fills completely with no air pockets, no burping.
The difficulty lies in keeping the vac pump oil from getting contaminated along the way from various internal process valve leaks, residual fluid on the test connector, etc. When it gets water-based stuff inside, the oil can't thoroughly seal the vanes because the water is micro-boiling. Hence vacuum levels go down. Change oil, vacuum level restored.