Abstract: A method of controlling a liquid ring pump in a pump system includes monitoring a vacuum pressure of the liquid ring pump using a pressure transmitter configured to transmit a vacuum pressure signal to a controller in operative communication with the liquid ring pump. The method also includes maintaining a predetermined vacuum pressure in the liquid ring pump under variable vacuum flow demand within the pump system in response to the vacuum pressure signal by controlling, via instructions from the controller, a parameter of the liquid ring pump based on a comparison of the vacuum pressure signal to the predetermined vacuum pressure by the controller.

Abstract: A first bore is formed in a liquid ring pump. A shaft is in the first bore. A second bore is formed in the pump and is axially inward of the first bore. A first and second seal are in the second bore and around the shaft. The second seal is axially outward of the first seal. The second seal is free of an abutment axially outward of it and abutting up against it.