1EN Series liquid ring vacuum pumps is fixed directly to motor flange. Motors are standard B3/B5 construction. The pump are high vacuum single stage type with vary port valve design.The only one moving part is rotor(impeller-shaft assembly) that has no inner rubbing part. Water must be supplied to pump as service liquid to form liquid ring and remove the heat resulting of gas compression in which from piston-like behavior of the liquid that is keeping nearly unchangedthe sucked gas temperature thanks to the isothermal compression.