Understanding Corrosion in Pumps and How to Deal With It
Research studies say that corrosion is one of the main reasons for pump failure. When buying pumping equipment, material selection and coating technology must be considered.
Within any industry, centrifugal pumps are considered to be among the most critical components. These pumps must have a sturdy design and should be made of robust materials. The knowledge of the pump engineer in the selection of components is crucial in deciding the reliability and durability of the pump. However, at times, even after taking all the precautionary measures, certain unexpected pump failures can still occur.
The Causes of Premature or Sudden Pump Failures
When a failed pump is inspected thoroughly, one can understand the reason for failure. If even one of the causes is understood, one can formulate strategies to correct it. Research studies say that corrosion is one of the main reasons for pump failure.
How to Prevent Corrosion in Pumps
Corrosion within centrifugal pumps can affect wet surfaces or a small portion of their internal components. Hence it could be general or highly localized. Normally, the highly localized and affected components cause pump failure. It is extremely important to find a solution to reduce the effects of corrosion.
Pump manufacturers spend a lot of time and money on research and development to create pump designs and materials to improve the efficiency of the pump, its performance and its durability. Let’s have a look at the different ways to reduce corrosion, which will not only help you save millions of dollars, but will also extend the lifetime of the pumps.
In addressing the problem of corrosion, material selection should be the first consideration. Corrosion can be dealt with and the rate of deterioration can be reduced by selecting the best material according to the operating conditions of the centrifugal pump.
Cast iron has a relatively low resistance to corrosion; it will quickly degrade the pump. Instead, pump manufacturers use stainless steel to avoid corrosion. (Learn more in the article Why is Stainless Steel Corrosion Resistant?)
Another method of dealing with corrosion is to apply a coating. You must understand that even the noblest metals are susceptible to corrosion. A coating isolates the metal surface from its environment. A wide range of factory-applied coatings, such as Fusion Bonded Epoxy (FBE) and polytetrafluoroethylene (PTFE) are available for fluid applications.
The effectiveness of a coating generally depends on the following factors:
- The type of coating
- The preparation of the coating
- The application of the coating
- The type of corrosion involved
- The type of fluid the coating is exposed to
As an industrialist, do not overlook the problem of corrosion when buying pumping equipment. Discuss your requirements with leading pump manufacturers and look for a consensus of opinion while selecting a specific material. You must also ask them to conduct a corrosion test in the same conditions of actual pumping. Pay attention to the velocity of the fluids to make a better choice. (When dealing with fluids, cavitative and erosive corrosion are common problems. Read Combating Cavitative Corrosion and Erosive Corrosion for some solutions.)
When you choose a pump for your industry, your material selection should be based on corrosion resistance and its overall cost, which includes initial cost, maintenance and replacement costs, downtime, life expectancy and its reliability factor.
Written by Parry Shah