Elmo Rietschle offers dry running and oil lubricated rotary vane pumps which cover a wide performance range. The eco-friendly dry running rotary vane pumps are used for vacuum, pressure and combined pressure and vacuum applications. The time-tested oil lubricated rotary vane machines are typically used for generating vacuum.
Operating Principle V-Series
Pressure increase by volume reduction is the principle behind rotary vane operation. In a cylindrical housing a rotor is positioned eccentrically so that it is on the top almost touching the cylinder. Rotor blades or vanes as they are called, are positioned inside rotor slots.
When the rotor starts turning, due to centrifugal force the blades are thrown out and slide against the internal surface of the cylinder. In this way a cell is formed between two blades with a volume that changes constantly during rotation. Air enters from the inlet port into a cell until the rear blade reaches the far end of the inlet port. At this point the cell has achieved its maximum air volume. As the cell then moves away from the port its volume becomes smaller and smaller, the air is thus compressed and the pressure rises. This continues until the pressure in the cell exceeds that in the pressure chamber and the compressed air then exits through the outlet port.
Some models are fitted with exhaust valves which stop the backflow of this discharged air if the maximum pressure has been reached. In a vacuum pump the process is similar, but the cell gives decreasing pressure, and the chamber is at atmospheric pressure. With pressure-vacuum pumps the lower end of the inlet port(s) for the vacuum is moved forward. The cell can now be filled through second inlet. To avoid impairing the vacuum, this second inlet port is located about one cell segment away from the main suction port. The ratio between vacuum and pressure capacities can be influenced by the choice of inlet port.