JZJLG Roots series screw dry vacuum pump unit is consists of ZJ type roots pump as the main pump, screw vacuum pump as a fore pump is composed of dry without oil vacuum unit. JZJLG Roots series screw dry vacuum pump unit than single screw vacuum pump is more suitable to work under low pressure, such as a vacuum distillation process to pumping rate 150L / s, work pressure is 2000Pa, choose JZJLG150-2 vacuum unit (10.5kw), than the selection of single 180 screw vacuum pump (22KW) more energy-saving and the unit can reach the lower limit pressure.