What are the factors that affect the actual air delivery of screw compressors? Theoretically, the air delivery of screw compressors depends on the inter-tooth volume, the number of teeth and the rotation speed. The inter-tooth volume is determined by the geometric dimensions of the rotor. In practice, for screw compressors, there are four possible causes why the actual air delivery is less than the theoretical air delivery:
Key Takeaways
- Rotary screw machines dominate continuous-duty industrial use, while piston machines suit intermittent, lower-flow tasks.
- Oil-free technologies safeguard sensitive processes; oil-lubricated designs are economical where air purity is less critical.
- Compare discharge pressure, output flow, motor power, and footprint before selecting a specific model.
The rotors and the rotors and the casing are not in contact during operation, and a gap is maintained, so gas leakage will occur. When the gas with increased pressure leaks through the gap to the suction pipe and the meshing groove being inhaled, the air delivery will be reduced. To lower the leakage, sealing teeth are made on the top of the driven rotor, sealing grooves are opened on the root of the active rotor, and ring-shaped or strip-shaped sealing teeth are also processed on the end face. If these sealing lines are worn, the leakage will raise and the air delivery will decrease;
The rotary screw machine is a positive displacement compressor, and the suction volume remains unchanged. When the suction temperature rises, or the suction line resistance is too large and the suction pressure is reduced, the density of the gas decreases, and the mass air delivery of the gas will be reduced accordingly;
The temperature of the gas will rise during the compression process, and the temperature of the rotor and the casing will also rise accordingly. For this reason, during the suction process, the gas will be heated by the rotor and the casing and expand, so the suction volume will be reduced accordingly. Some of the rotors of screw compressors are cooled by oil, and the casing is cooled by water. One of the purposes is to lower its temperature. When the cooling effect is not good, the temperature rises and the air delivery will decrease;
Speed.
The air delivery of the rotary screw machine is proportional to the speed. The speed often changes with the voltage and frequency of the power grid. When the voltage decreases (for asynchronous motors) or the frequency decreases, the speed will decrease, reducing the gas volume.
Panrui Compressor: Your Dependable Compressor Vendor
There are roughly three levels of water removal in the exhaust of compressors:
- Technology configuration
- Strike Cost
- Import and ship assistance
Selection and Sizing Considerations
Rotary screw machines dominate continuous-duty industrial use, while piston machines suit intermittent, lower-flow tasks. Oil-free technologies safeguard sensitive processes; oil-lubricated designs are economical where air purity is less critical. Compare discharge pressure, output flow, motor power, and footprint before selecting a specific model.
Frequently Asked Questions
What is the main advantage of a screw compressor?
It delivers continuous, stable air flow with low vibration and is ideal for round-the-clock industrial operation.
When is a reciprocating compressor the better choice?
For intermittent use, high-pressure applications, or lower initial budgets, piston compressors remain a practical option.
What does two-stage compression enhance?
Two-stage compression reduces the compression ratio per stage, improving efficiency and lowering discharge temperature.
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