Pump killers: How to fight the 13 most common centrifugal pump failures? Number 2.

In the series “Pump killers” we investigate the 13 most common causes of centrifugal-pump failure and take a look at the measures that can be taken to fight these ‘killers’. Every week we will share a new, even bigger, killer. Our goal: to reduce the number of victims by sharing our knowledge.

?We have a huge arsenal of photos of this week's "killer". This is not good news, because it means that this killer is far too common; not surprising that he is number 2. This week we are going to talk about medium, about how this is important for the choice of material for a pump and how this can still go wrong in practice, even if it has been carefully selected. So let's start quickly:

Although a centrifugal pump is designed to pump a medium, it is very important to know which medium we are talking about. Depending on the composition of the medium, including: temperature, PH value, contamination and chemical properties, materials must be selected. So far nothing wrong, but if this were the case, we would not have had that entire library of practical examples.

Photo: "Material dissolved by the medium." - credit: Oveducon.

And that is right, because in daily practice, the combination of medium properties and material resistances is sometimes neglected, with all the associated consequences. In the eyes of many pump users, a pump is only an aid to get a medium from A to B. However, it is not that simple and the pump will let you know unexpectedly sooner or later..

Photo: "Dirt in a fan." - credit: Oveducon.

How does this phenomenon arise? When purchasing a centrifugal pump, attention is often paid to the selection of the correct materials from which the pump is composed.

The pump is then ordered, installed and commissioned and runs for a period with the medium for which it was purchased. In practice, however, it often happens that the composition of the medium is adjusted or the pump is used to pump a different medium. Is it being considered whether the pump parts can withstand this? In many cases not, and the life of a pump (part) is greatly reduced.

Photo: "Impeller affected by erosion corrosion." - credit: Oveducon.

Small changes can have a major effect: for example, a small leakage of a few oil droplets in a medium of water can cause the rubber bellows of a bellows seal to be severely corroded, causing malfunctions in the system.

Photo: "Bellows heavily affected by the medium." - credit: Oveducon.

What are the consequences? Everyone is looking for a reliable centrifugal pump that has low maintenance costs, but in this case we see just the opposite.

When using materials that are not resistant to the medium properties, we see:

- The maintenance costs rise sharply;

- Frequent unexpected stops are required due to failure of pump components;

- Leaks from seals;

- Leaks from closures;

- Leaks from the pump housing and / or pipe system.

Photo: "Pollution from a fan of a sewage pump." - credit: Oveducon.

How can this be controlled? As far as we are concerned, combating is 'simple': give the centrifugal pump the attention it deserves. If you compare a pump user with a car owner, you can see a lot of difference in care for the product.

People spent a lot on a car, we fill up with special, more expensive petrol, we don't think the best motor oil is good enough, when you hear a beep, the car is already at the garage and when refueling, we generally look carefully at which fuel needs to be put in the tank.

So why don't we do this for a centrifugal pump? If a centrifugal pump were to receive the same attention as a car, a lot of money could be saved worldwide.

What are your experiences with this killer and what are you doing to combat it?

Next week we're ready for the biggest pump killer of them all and we're going to look at ways to get it off its number 1 position. Until then!