What is Vane Compressor?
The vane compressor uses centrifugal force for the air compression process. It is also called a sliding vane compressor or rotary vane compressor. On June 16, 1874, Charles C. Barnes was designed the first vane compressor.
The vane compressor has the same working principle as other compressed air expansion engines. A special cast alloy uses for the construction of the vanes. Maximum vane compressors oil lubricated. It means these compressors need proper lubrication for proper operation, and they can’t run dry.
This type of compressor has a rotor, a set of vanes fixed on the impeller, and a casing.
As the rotor rotates, a centrifugal force presses the vanes against the stator wall. As the cavity generates between the stator and rotor, the air from the environment is sucked into the compressor.
As the air enters the compressor cavity, its volume decreases as it rotates. When the air strikes the rotor vanes, its speed increases. After passing through the rotor vanes, the air enters the stator blades. The stator converts the speed of the air into pressure and discharges it.
Vane compressors are used all over the world for different applications. They have multiple types designed according to the nature of the applications.
These compressors are typically employed for pressure ratios up to 8:5 and capacities up to 150 m3/min. Vane compressors are most commonly used in hydraulic and automotive services.
Construction of Vane Compressor
The vane compressor has a cylindrical rotor, stator, rotor vanes, inlet, and outlet ports.
The rotor is installed inside the compressor housing. It has multiple vanes. The main function of the rotor vanes is to provide K.E to the air and increase the air speed.
The rotor has multiple radial slots. Each radial slot contains a spring-loaded vane. Synthetic fiber or steel is used for the construction of the vane.
The housing has inlet and outlet ports. The inlet port has more entrance area than the outlet port. The compressor has a reducing area from the inlet side to the outlet side. This inlet port uses to introduce air into the compressor. The outlet port uses to discharge the compressed air.
The compressor has a drum installed inside the housing. In the case of an oil-lubricated compressor, a thin layer of oil uses in between the casing and the vane.
In this compressor, the air leakage may reduce by increasing the number of vanes. Because by increasing the number of vanes, the pressure difference reduces between adjacent spaces around the roto.
A large number of blades also helps to increase the pressure ratio. Cane compressors require less input work than root blowers for a given pressure ratio.
Working of Vane Compressor
A vane compressor uses a centrifugal force to compress the air or gas. An electric motor or generator drives the rotor of the compressor.
When the motor drives the rotor, the rotor vanes start rotating outward toward the compressor hosing until they make a connection with the housing.
As the rotor vanes reach on the area where the clearance between the housing and the rotor drum becomes very small, the vane springs compress to make contact with the housing. When the spring is compressed, the gap between the two in-line vanes also reduces.
In the same way, as the vanes reach on an area where the clearance between the housing and the rotor drum increases, the vane springs enlarge to ensure contact with the housing. Due to the expansion of the springs, the gap between the two adjacent vanes also expands.
As the vanes move down, the gap between the compressor housing and the rotor drum increases. Due to this, a vacuum or cavity generates between the housing and drum. The greater the clearance between the housing and the rotor drum near the suction port of the vane compressor, the greater the vacuum produces between the two adjacent vanes.
This vacuum generates a pressure difference between the compressor’s inner and environmental pressure. As the pressure difference generates, the inlet port opens, and the air is sucked from the environment into the compressor.
As the suction process completes, the rotor vanes start to rotate and make a connection with the compressor casing. As the vanes make a connection with the casing, the area between adjacent vanes reduces, the air volume starts decreasing, and the air is compressed.
After the compression process, the compressed air discharges through the outlet port and transfers to the desired area.
Advantages of Vane Compressor
- This type of positive displacement compressor generates an excellent cavity for suction.
- The vane compressors are best for high compression services.
- They supply a continuous air flow.
- These compressors have a long service life.
- These compressors are best suitable for moderate pressure applications.
Disadvantages of Vane Compressor
- It generates extensive vibration.
- These have more moving parts than piston compressors.
- These have tough maintenance because of many moving parts.
- They have high maintenance or service costs.
Applications of Vane Compressor
The most common applications of the vane compressors are given below:
- These types are most commonly employed in agricultural applications such as to operate material conveying and farm machinery.
- The vane compressors are used in tire inflation shops.
- It uses in the dry-cleaning machine.
- It uses to operate the paint pump.
- They are employed to operate air knives for peeling and cutting.
- They also use for woodworking tools and air-operated metal.