Water ring vacuum pumps of the PW.4.21 series are two-stage vacuum pumps. They are designed for suction and pumping of dry gas with a temperature of up to 150°С and gases saturated with vapors, distinguished by the fact that their temperature does not exceed 100°С, with the possibility of using working fluids with a viscosity of up to 60 mm 2 / sec and a density of 800 - 1200 kg / m3, the water temperature at the pump outlet should not exceed 80°С. In pumps of the PW series, the pump and motor are mounted on a common support. Torque from the engine is transmitted to the impeller through a shaft installed in support bearings and an elastic coupling. This design makes the vacuum pump significantly longer and heavier, but due to this, it significantly facilitates its maintenance when disassembling the pump or replacing the motor is required. In addition, the pump is installed on 2 supports (impeller between bearings), which gives a longer service life.
