There's a good reason why piston and vane vacuum pumps are designed with a water jacket: they're subjected to a lot of heat that can cause pumps to fail. Heat comes from adiabatic compression of the gases they are exhausting from a chamber, and from the process. Either way you have to eliminate heat and keep the pump running a proper temperature. We recommend running the Stokes 212 and 412 pumps at 130° F to 140° F oil temperature.
To reduce water consumption, we recommend use of a water modulating valve. New MHV pumps come with this as standard, like the HS430 at right.
When you are using a closed-loop cooling system, be sure the coolant is at the right temperature and the system is working properly. Watch out for blockages if running water to an outside drain, for example, in cold climate when freezing can occur.
For a 1600 CFM blower backed by a 300 CFM mechanical pump, the cut in pressure should be 15-20 torr.
Starting a blower at too high a pressure overloads the blower and drive motor; starting at too low a pressure wastes time.Blower cut in pressure depends on the CFM of the blower and backing pump.Metallurgical High Vacuum Corp., 6708 124th Avenue, Fennville, MI 49408, United States