Connecting pipes to self-priming pumps

Not only is an appropriate pump setup essential but also the way it is connected to the pipes. The pipe system has to be checked carefully for a pump to be able to operate optimally. This is where things usually go wrong, but this can be avoided by paying close attention to a system's actual pipe diameters. Although this usually requires a greater time investment, you will benefit from it in the long term.

  • Assembling pipes
  • Assembling suction pipes
  • The pressure pipe

Assembling pipes

Generally, flanges, screw threads, or swivels are used to attach pipes to a pump, and the kind of fastening method most suitable partly depends on the type of pump. To be able to assemble the flanges, a sheet gasket is fitted between them, which always needs to be resistant to the liquids to be pumped. Of course, no dirt can be permitted to enter the pipes during assembly, as this could seriously affect the pump's performance.

Assembling suction pipes

The extent to which a pump is able to perform optimally depends on several important factors, one of which involves the suction pipe and the attendant suction conditions. Most faults in centrifugal pumps arise in these suction pipes, meaning that correct assembly is absolutely essential.

A well-assembled suction pipe should meet the following criteria:

  • Connections in the suction pipe are free of any air or liquid leaks;
  • The length of the suction pipe has been kept as short as possible to prevent any pipeline loss;
  • To avoid air bubbles, the suction pipe has been attached to the pump at an ascending angle;
  • Turbulence and additional pipe loss in the suction pipe are prevented by limiting the number of bends, and the radius of the assembled fittings has also been kept as wide as possible;
  • The diameter of the suction pipe is larger than that of the pump's suction opening;
  • The end part of the suction pipe, before the pump inlet, is completely straight;
  • Pumps that are not self-priming (with the liquid level below the pump) have been fitted with a foot valve with a large outlet;
  • If contaminated liquids are expected during the draining process, a strainer or dirt grid has been installed in the pipe;
  • To prevent swirling as effectively as possible, the end of the suction pipe is placed as far below the liquid level as possible;
  • Every effort has been made to prevent an unobstructed flow into the suction tank. An obstruction may cause air bubbles in the liquid to be pumped, and will affect the pump's performance.

The pressure pipe

In addition to a suction pipe, the centrifugal pump should also be fitted with a pressure pipe, but the criteria to be met differ. For example, the applicable standards for minimum and maximum flow rates and for the minimum pipe diameter when using a pump are to be observed when the pipe diameter is determined.

Please refer to the most common suction-related problems in our blog: Suction problems with irrigation or booster pumps