Corrosion-proof pumps for pump pits

To get a sustainable solution when handling spills, it is important to choose the right type of pump. Many times, the liquid to be pumped is corrosive, which places demands on safety. At Lyma, we explain how to think when choosing pumps.

Vertical pump from Savino Barbera with recessed impeller.

In all industries, spillages occur, which means that a pump pit must be available. In the past, it was common to use a submersible pump, i.e. a centrifugal pump placed in the spill that pumped the media to where it was needed.

This often resulted in pump pits that collected not only liquid but also other particles such as sand, nuts, gloves and screwdrivers. Another disadvantage of this solution was also that it created a sticky mass, often containing corrosive substances which in turn led to a poor working environment.

Vertical pumps

Instead of having a submersible pump, you can use a vertical centrifugal pump that has the impeller down in the medium and the motor above the liquid surface. These pumps are available off-the-shelf and can handle most media handled in industry. Typical plastic materials for this type of pump are PP, PVC or PVDF, materials that allow the pump to handle the entire pH scale from 0-14.

Dry running safe pumps

A common problem that often occurs with pump pits is that plastic ends up in the pit. This leads to the inlet becoming blocked, which can cause dry running. By using a pump without slip rings instead, it becomes dry-running safe.

If you know that particles often end up in the pump pit, it can also be good to have a recessed impeller on the pump that allows it to handle more and larger particles. However, it is important to note that a recessed impeller reduces the efficiency of the pump.

Texel magnetic drive centrifugal pump

Self-priming centrifugal pumps

If a pump that is not in the medium is needed, a self-priming centrifugal pump can be a good alternative. This type of pump has an integrated suction tank that evacuates the air from the suction line, allowing the liquid surface to be approximately four metres below the pump. As the suction container has no valves, the design is very reliable and dependable. A self-priming centrifugal pump is also dry-running proof and is available in plastic materials such as PP or PVDF.

DEPA pneumatic diaphragm pump

Compressed air driven diaphragm pump in pump pit

If the pump pit is to be placed in an environment without access to electricity but with compressed air, a diaphragm pump is a good and cost-effective option. This type of pump is self-priming, which allows it to be placed above the liquid surface. If it is to be placed in a pump pit instead, it is important to check that the pump material can withstand the media. These pumps are available in metals such as aluminium and steel, but also in plastics such as PP and PTFE. It is worth noting that and compressed air driven diaphragm pump can pump particle sizes up to 10 millimetres.

Lyma has experience

At Lyma, we have been working with pumps and handling of corrosive liquids for over 40 years, and have extensive experience in pump and material selection. Contact us directly may receive personalised service or read more about us.