Rotary vane pumps are positive-displacement pumps consisting of vanes mounted to a rotor that rotates inside of an oil-sealed cavity. These moving vanes transport volumes of gas through the system and out of an outflow.
Rotary Vane Pump Principles
The above diagram illustrates the pump action. The rotary action of the pump creates a hollow space in the chamber (1) which expands as the pump rotates. As the chamber expands, the pressure in the chamber decreases. As a result, gas is drawn into the chamber due to the difference in pressure between the chamber and the inlet (4) to the chamber. The inlet is the only place where gas can flow into the chamber.
Once the vane (3) moves past the inlet (4), it seals the inlet against the chamber (1) and the gas becomes trapped between the two vanes (2 and 3). The chamber (1) then begins to decrease in volume as the rotor revolves toward the exhaust port (5), compressing the gas. The pressure of the compressed gas becomes greater than atmospheric pressure. When the vane (2) moves past the exhaust port (5) the compressed gas in the chamber is forced out through the exhaust port. This expansion/compression cycle constitutes one complete cycle of the pump. This cycle is repeated as the vane (2) passes the intake port and seals it against the atmosphere. Two pump cycles are performed during each revolution of the pump rotor.
As this type of pump requires oil in the system regular oil changes are required for optimal performance. A common pump feature to assist with this is a sight glass which allows easy viewing of the oil level and facilitates deciding when it needs changing.
Two-Stage Rotary Vane Pumps (CRVpro Series)
Two pump stages (2 and 1) are arranged in series in order to improve the end pressure and the pumping speed at lower pressures. The intake takes place in the first stage (1), the compression and the outlet in the second stage (2).
These pumps are able to achieve a higher compression ratio giving much lower vacuums than diaphragm pumps, so are often used in more demanding applications such as freeze drying, degassing, vacuum ovens and concentrators.
The CRVpro range of Rotary Vane Vacuum Pumps provides an extensive selection of pump sizes (tables below) with the following benefits:
- High reliability for stable operation and long product lifespan
- Extended oil change intervals reducing maintenance costs
Three features drive these benefits:
- Runs 10°C cooler than comparable pumps – slows corrosion
- Has a 40% larger oil capacity than comparable pumps – dilutes aggressive chemicals
- Has a chemical resistant coating in the oil case and pump module – protects non-moving parts
Other features are illustrated in the diagram below.
CRVpro Stand-Alone Pumps
|Free Air Displacement @ 60 Hz, cfm (L/min)||2.8 (78)||4.2 (118)||5.6 (158)||12.8 (363)||18.3 (519)||22.1 (627)|
|Free Air Displacement @ 50 Hz, m³/hr (L/min)||4 (67)||6 (100)||8 (133)||18.3 (305)||26.2(436)||33.1 (551)|
|Ultimate Pressure, mbar (torr)||5×10⁻⁴ (4×10⁻⁴)||5×10⁻⁴ (4×10⁻⁴)||5×10⁻⁴ (4×10⁻⁴)||3×10⁻⁴ (2×10⁻⁴)||3×10⁻⁴ (2×10⁻⁴)||3×10⁻⁴ (2×10⁻⁴)|
|Noise Level, dBA||50||50||50||55||55||55|
|Motor Speed, RPM, @60Hz, @50Hz||1740 (1450)||1740 (1450)||1740 (1450)||1750 (1450)||1750 (1450)||1750 (1450)|
|Motor Power, 0.37 (kW)||0.37||0.37||0.37||0.7||0.7||0.7|
|Oil Capacity, mL||1150||1150||1000||2400||2200||2100|
|Connection Flanges||DN 16||DN 16||DN 16||DN25||DN25||DN25|
|Dimensions, LxWxH, mm||463 x 157 x 230||463 x 157 x 230||463 x 157 x 230||569 x 206 x 289||569 x 206 x 289||569 x 206 x 289|
CRVpro Pump Kits (Pumps + Accessories)
|CRVpro 4||CRVpro 6||CRVpro 8|
|CRVpro Basic Package
|CRVpro Measurement Package
A selection of accessories are available for these pumps: