A vacuum in a centrifugal pump is created by the rotation of the impeller.
Here's a breakdown of the process:
- Impeller Rotation: The impeller, containing curved vanes, rotates within the pump casing.
- Outward Force: As the impeller spins, it imparts kinetic energy to the fluid within the pump, forcing it outward towards the volute or diffuser.
- Pressure Reduction: This outward movement of the fluid creates a region of low pressure or a partial vacuum at the "eye" or center of the impeller.
- Suction: The vacuum generated at the impeller eye draws fluid from the suction pipe into the pump. Atmospheric pressure acting on the fluid in the suction source helps push the fluid into this low-pressure zone.
In simpler terms, the spinning impeller throws the fluid out, creating space (a vacuum) at the center, which then pulls in more fluid. The atmospheric pressure helps push this fluid into the pump.
