Screw Blowers

A screw blower, also known as a rotary screw blower, is a type of blower that uses two rotors in the shape of screws to compress air. In a water or wastewater treatment plant, screw blowers are mainly used in the aeration process. They supply oxygen to the microbes in the aeration tank, which is essential for the biological oxidation processes. The rotors rotate in opposite directions, trapping air between them and the stator wall, and thus compressing the air.

• Aeration stages in both water and wastewater treatment plants
• Bio-solid composting processes
• Air scouring in filter beds

• Monitor the blower's performance regularly, checking parameters such as pressure, temperature, and flow rate.
• Perform routine maintenance, including lubricating the bearings, checking seals for leaks, and regularly changing the oil.
• Pay attention to warning signs of failure, such as unusual noises, excessive heat, or decreased performance.

• Rotors: The two screw-shaped rotors rotate in opposite directions to compress air. The size and shape of the rotors can affect the performance of the blower.
• Housing: The housing contains the rotors and ensures a tight seal for compression. The material of the housing, usually cast iron or steel, must withstand high pressure.
• Drive system: This system, typically a belt or direct-drive, transfers power from the motor to the rotors.
• Cooling system: This system prevents overheating of the blower. It may be an air or water-cooled system.

• Sizing Parameters: To properly size a screw blower, the following parameters need to be considered:
• Flow rate (in CFM or m3/hr): This is the amount of air the blower needs to deliver.
• Pressure (in psi or bar): This is the pressure at which the air needs to be delivered.

• MasterFormat Section: 44 42 13.16 - Rotary-Screw Blowers

• Atlas Copco: ZS series
• Kaeser: CBS series
• Gardner Denver: CycloBlower H.E. series

• Centrifugal blowers: They work on a different principle and may be preferred in applications requiring high flow rates but at lower pressure.
• Lobe blowers: These are similar to screw blowers but may be preferred when cost is a significant factor as they are typically less expensive but also less efficient.