Pump system with vacuum source

A method of changing the capacity of a liquid ring vacuum pump comprising the steps of:

• providing a vacuum pump comprising a base member, a first port plate, an original cover defining an impeller chamber, and an original impeller having one or more pumping characteristic disposed within the impeller chamber, the base member being adapted to receive a drive shaft, and the impeller being fixed to the drive shaft;
• the vacuum pump having an intake port and a discharge port, the port plate separating the intake port from the impeller chamber and having at least one port therethrough for providing fluid communication between the intake port and the impeller chamber;
• removing the original cover from the vacuum pump;
• removing the original impeller from the vacuum pump;
• installing a new impeller onto the vacuum pump, the new impeller having one or more different pumping characteristics than the original impeller;
• and
• installing a new cover onto the vacuum pump, the new cover defining an impeller chamber that accommodates the new impeller.

A liquid ring vacuum pump comprising:

• a drive side housing;
• an outside housing, the drive side housing and the outside housing defining an impeller chamber having a central axis;
• a first port plate;
• a second port plate;
• an impeller disposed in the impeller chamber between the first port plate and the second port plate and laterally offset from the central axis of the impeller chamber;
• an intake port, the first port plate separating the intake port from the impeller chamber and having at least one port therethrough for providing fluid communication between the intake port and the impeller chamber;
• and
• a discharge port, the second port plate separating the discharge port from the impeller chamber and having at least one port therethrough for providing fluid communication between the discharge port and the impeller chamber.