6 Basic Rules For Centrifugal Pump Piping

1. Keep the suction line as short as possible
Leave a straight length of 5 to 10 pipe diameters between the pump suction and any obstructions in the suction line. Note: Obstructions include valves, elbows, tees, etc. Keeping the pump suction line short ensures that the inlet pressure drop is as low as possible. Straight pipe allows for uniform flow velocity across the entire pipe diameter at the pump inlet. Both are important for achieving optimal suction results.

2. The pipe diameter on the suction side should be Greater than or equal to the pump inlet size

3. Use an eccentric reducer on the suction side

When a pipe size conversion is required, consider using an eccentric reducer on the suction side of the pump. When the flow is coming from below the pump, the reducer will be installed top-flat. If the flow is coming from above the pump, the reducer will be installed bottom-flat. The purpose of this design is to prevent air pockets from forming on the suction side of the pump.

4. Eliminate elbows installed at and near the pump inlet
Install a straight pipe section of 5 to 10 pipe diameters between the pump inlet and the elbow. This helps eliminate "side loads" on the pump impeller and creates an even pump axial bearing load.

5. Eliminate the possibility of air entrapment in the suction line
1) Maintain sufficient liquid level in the supply tank to prevent vortex formation and air entrainment.

2) Avoid the formation of high cavities in the suction line that may entrain air.

3) Under suction vacuum conditions, keep all pipe and joint connections sealed to prevent air from entering the pump.

6. Ensure that the piping arrangement does not stress the pump casing