This Technical Information Paper is provided to assist in evaluating performance of single stage, liquid ring vacuum pumps. Cone ported liquid ring vacuum pumps are the most common source of paper machine vacuum in the pulp and paper industry. This paper is also applicable to other designs of single stage liquid ring vacuum pumps exist such as flat plate ported. This design of a liquid ring vacuum pump is typically equipped with two top suction flanges and two side or bottom discharge flanges. Often the suction flanges are manifolded together as are the discharge flanges.