How do Positive Displacement Blowers work?
Although there are several replies for how does a roots blower operate, this explanation is the most comprehensive one among others. Roots blowers work on the principle of positive displacement, which involves trapping a fixed volume of air or gas between the blower’s components and then discharging it at a higher pressure. They consist of two or three lobed rotors, which are also called bi-lobed and tri-lobed, that rotate in opposite directions inside a casing, creating a continuous flow of gas or air without the need for valves or other moving parts.
As the rotors turn, air is drawn into the blower inlet and trapped between the lobes and the casing. There is a clearance between the lobes. As the rotors continue to rotate, the trapped air is moved around the casing to the discharge side, where it is expelled at a higher pressure. This process is repeated continuously, resulting in a steady air flow or gas flow.
Here are the steps of the operation of a Roots blower:
Intake: The lobes of the Roots blower rotate, drawing in air or gas through the inlet port. As the lobes rotate, the space between the lobes and the housing of the blower expands, creating a vacuum that pulls the air or gas into the blower.
Compression: As the lobes continue to rotate, the air or gas is trapped between the lobes and the housing. This trapped volume of air or gas is compressed as the lobes move toward the outlet port. Since the lobes are in constant contact with each other and the housing, the compression is continuous.
Exhaust: When the lobes reach the outlet port, the compressed air or gas is discharged into the system or application. As the lobes continue to rotate, the volume between the lobes and housing expands, allowing the blower to draw in another volume of air or gas.
This process repeats continuously, with the Roots blower producing a steady stream of compressed air or gas. Roots blowers are commonly used in industrial applications such as wastewater treatment, pneumatic conveying, and chemical processing.