A vacuum pump arrangement for a milking plant comprising a main vacuum conduit (1) comprises at least two vacuum pump units (3) for maintaining a system vacuum in the main vacuum conduit. Each of the vacuum pump units comprises a pump (4), a vacuum tank (6) connected to the pump by an intermediate conduit (7), and an inlet conduit (11) connecting the vacuum tank to the main vacuum conduit. A drainage (13) extends from the vacuum tank and comprises a draining valve (14). The pump sucks air from the main vacuum conduit via the inlet conduit, the vacuum tank and the intermediate conduit. The vacuum pump unit comprises a closing valve (11 a) provided on the inlet conduit and configured to close the inlet conduit in an automatic manner when the pump has been stopped.
