4.7.3.4 Gas-circulation-cooled Roots pumps

Gas-circulation-cooled Roots pumps can be operated without a backing pump. Large pressure ranges and very high differential pressures are the ideal use for this type of pump. Continuous use is possible at high differential pressures since the gas that is heated up by compression is cooled on the pressure side and partly fed back into the suction chamber. This makes them suitable for operation at atmospheric pressure if they are used in combination with gas coolers. Gas-circulation-cooled Roots pumps are available in sizes from 500 m³ · h^-1 (18.5 kW drive power) up to 8,000 m³ · h^-1 (200 kW drive power).