The inventor of the Rotary Vane Pump is GAEDE. There are two types of Rotary Pump.
- Rotary Vane Pump
- Stationary Vane Pump
Although the working principle of these two is the same. There is one heavy cylindrical shaft. We call the shaft as the rotor of the pump. This rotor rotates eccentrically in a hollow cylinder. The hollow cylinder is the stator of the rotary pump. The eccentric rotation of the rotor inside the stator compresses the gas or any other fluid inside the space between the stator and the rotor. Therefore the compressed gas or the fluid comes out through the outlet of the rotary pump through a nonreturn valve.
Generally, the entire pumping system is immersed inside a vessel of oil. There are a few advantages of immersing the entire pumping system in the oil.
- There is no need for using any external lubrication for the moving parts of the rotary pump.
- This arrangement also prevents the leakage of gaseous fluid from the pump during its operation.
- The oil also serves as the coolant of the pump.
Rotary Vane Pump
We also refer to this pump as Gaede Rotary Pump after the name of its developer. In this article, we shall discuss the rotary vane pump. Then we shall discuss the stationary vane pump in a separate article.
Construction of Rotary Vane Pump
There is a stator in the form of a metallic hollow cylinder. Also, there is a metallic rotor in the shape of a solid cylinder. The shaft of the rotor is fixed centrally on it. But the shaft of the rotor is placed eccentrically in the stator. Therefore with the rotation of the shaft, the rotor rotates eccentrically. The diameter of the rotor is such that the periphery of the rotor always touches the inner peripheral wall of the stator between the inlet and outlet. The rotor consists of two grooves. There are two vanes fitted on these two grooves with spring pressure. Due to the spring pressure, the tip of the vanes always touches the inner peripheral wall of the stator during all angular positions of the rotor.
These vanes divide the space between the rotor and stator inside the rotary pump into segments. There is no volumetric link between these two segments. There is one inlet as well as one outlet in the stator of the rotary vane pump. The suction pipe of the pump connects the inlet with the vessel where a vacuum is to be created. The outlet of the pump consists of a non-return valve.
Working Principle of Rotary Vane Pump
A prime mover motor, coupled with the shaft, rotates the rotor. As per the model, shown in our figure, we need to rotate the rotor anticlockwise to demonstrate the working principle of a rotary vane pump.
During the anticlockwise rotation of the rotor, the segment of the space under the inlet gradually increases. Therefore the pressure inside the segment decreases. As a result, the fluid comes in that segment of the space from the vessel through the inlet.
At the same time, the segment of the space under the outlet gradually decreases. Therefore, the fluid inside this segment gets compressed. Due to the pressure of the compressed fluid, the valve associated with the outlet of the rotary vane pump gets open. As a result, the fluid gets out of the outlet through the valve.
The process of suction and delivery of fluid takes place during every rotation of the rotor. In other words, the process repeats during every rotation of the rotor. Therefore, the pumping continues until the rotor rotates in the rotary vane pump.
This type of pump mainly acts as a vacuum pump. We can create up to 10 – 3 Tor vacuum with the help of this pump.
Main Advantage of using a Rotary Vane Pump
The main advantage of using a rotary vane pump is that it can start its working from normal atmospheric pressure. Therefore, we do not need any auxiliary pump to reduce the pressure inside the vessel before using this pump.
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