Features:

- Two-Shift adjustable gas ballast valve satisfies different requirements of condensable vapor(such as water vapor) to be exhausted out of pump in different processes.

- Dual protection of oil anti-sucking back ensures vacuum system from oil pollution when pump stops running and needs to be easily restarted.

- Forced oil circulation system consisted of oil pump and constant pressure oil supply mechanism ensures stable running of the pump.

- Less components are used, easy to maintain and repair.