We have specialised in corrosion resistant pumps since 1973 so can almost certainly find you a solution to your application. Our chemical resistance table shows just some of the liquids we have experience pumping, but please talk to us to find the best chemical pumping solution for you.

We’ve manufactured pumps for nearly 50 years and have always prided ourselves on our quality and reliability. In the years we have been ISO9001 certified, at the last count we have supplied 4300 pumps and 41 of them had an issue (that’s 0.95%) due to us making an error. Therefore 99.05% of all our pumps supplied have been successfully and reliably pumping corrosive liquids for many years.

When we put our name on a pump, we’re making a serious commitment to give you great quality life-long service for pumps that will last. No matter how old your pump becomes, in the unlikely scenario that you have a problem, our engineers will be on hand to diagnose the issue and help you get up and running again. We promise to give you this support from day 1 to year 25 and beyond.

Yes, absolutely! Sometimes the best way to really understand an application and find the best, most reliable solution for you is via a site visit which can be carried out free of charge at any time. Simply talk to us and we can get something booked in.

And because we are certified pump system auditors, you can be assured we will find you the best long term solution for reliability and cost effectiveness.

Possibly a lot more than you realised! The purchase price is just the beginning of a pump’s life cycle cost as half of the energy consumed in the average plant is consumed by pumps. To read more about how you could save money on your pumps, click here or to carry out your own calculations click here.

Magnetic drive pumps are centrifugal pumps that use a magnetic coupling to transmit power from the motor to the impeller. The drive magnet is mounted on the motor shaft that will connect by magnetic force to driven magnets contained within the pump. This type of pump is ideal for applications where leakage or contamination of the pumped fluid is a concern, as there is no mechanical seal or shaft seal to fail. 

Magnetic drive pumps are used in a wide variety of applications, including chemical processing, water treatment, and metal finishing. They are designed to provide a reliable and efficient solution for transferring corrosive and hazardous liquids. The pumps are constructed with a non-metallic construction, making them ideal for use in highly corrosive and hazardous environments. 

  • Check the pump regularly for signs of wear and tear.
  • Ensure the pump is properly lubricated.
  • Check the bearings for any signs of wear or damage.
  • Ensure that the pump is properly aligned with the drive motor.
  • Check the temperature of the pump and ensure it does not exceed the recommended levels.
  • Ensure that the pump is running at the correct speed. 

Chemical pumps work by using a combination of force and suction to move liquid or gas from one location to another. The pump is driven by an electric motor or other power source, and the force of the motor is used to move the liquid or gas through the pump. The pump then uses suction to draw the liquid or gas into the pump and then expel it out the other end. This process if repeated until the desired pressure and flow rate is achieved. 

There are many types of chemical pumps including centrifugal and diaphragm pumps but what they have in common is the materials of construction that need to be resistant to the pumped medium. Plaastics and rubbers are common choices but also exotic metals, ceramic and even glass may be selected according to their suitability. 

Viscosity is a measure of a fluid's resistance to flow. It affects centrifugal pumps in a variety of ways, including how much power is needed to move the fluid, how quickly the pump can move the fluid, and how efficiently the pump can move the fluid. Higher viscosity fluids require more power to move and take longer to move through the pump, whilst lower viscosity fluids require less power and can move through the pump quicker. 

Anything over 25cP (centipoise) will have a significant effect on the performance of centrifugal pumps. 

  • Firstly, and most importantly : read through the manufacturer's installation and operation manual.
  • Ensure that the pump is running in the correct rotation with a flick test (quickly on and off.)
  • Open the suction valve and flood the pump.
  • Close, or partially close the discharge valve, depending upon operating conditions.
  • Open any cooling or recirculation lines, including any seal flush or system.
  • Start the pump drive.
  • Slowly open the discharge valve until the pump reaches the desired flow.
  • Check the discharge pressure gauge to ensure the pump is operating within its parameters.
  • Do not operate the pump below its minimum flow requirements or above the maximum recommended flow rate. 

A diaphragm pump is a type of positive displacement pump which uses a flexible diaphragm as the only moving part to create pressure and move fluid. It is typically used in applications where a low flow rate, high pressure, or a pulsating flow is required. 

A centrifugal pump is a type of rotodynamic pump that uses a rotating impeller to create pressure and move fluid. It is typically used in applications where a high flow rate ir required. 

Centrifugal pumps are not inherently self-priming and need to have a sufficiently flooded suction to work efficiently. They can be made to self-prime by utilising an integrally designed casing that recirculates liquid around the pump until all air in the suction line is evacuated or by installing a priming chamber on the suction side of the pump. This chamber is initially filled with liquid,when the pump starts this liquid is evacuated causing a vacuum in the suction line that draws liquid into the chamber and then the pump. It is important to always consult the manufacturer who will advice on maximum suction lifts. 

Multistage pumps are a series of impellers and casings mounted one after the other in series so that the discharge of one casing enters directly into the suction of the next. As each stage will only elevate the pressure by a set amount a multistage pump will increase the pressure in each stage so that a final high pressure comes from the last stage. 

For instance, taking an example of a 10-stage vertical pump, and each stage can increase the pressure by 0.5 bar. Liquid enters the first stage at atmospheric pressure and is elevated by 0.5 bar to enter the second stage, this then increases the pressure by 0.5 bar to enter the third stage at 1 bar. This is repeated until the liquid exits the final stage at 5 bar pressure.

It's important to note that only the pressure is increased and not the flow rate as the stages are mounted in series. To increase the flow rate, you would need to mount the pumps in parallel. 

Pump cavitation is a common problem caused by the formation of bubbles in liquid due to a decrease in pressure. It can cause significant damage to the pump and reduce their efficiency. To prevent cavitation, it is important to ensure that the pump is properly sized and installed, and the system is designed to operate at the correct pressure.

Here are some tips to help prevent pump cavitation:

  • Ensure the pump is properly sized for the system - over or under sizing the pump can cause cavitation.
  • Low pressure can cause cavitation, so be sure the system is operating at the correct pressure. 
  • Check for any obstructions in the system, such as valves or fittings.
  • Check for any air leaks in the system.
  • Install a suction strainer in the system to prevent ebris from entering the pump. 

Understanding MEI for Pumps Exceeding 0.7

Pumps are an essential part of many industries, and it is important that they operate as efficiently as possible. The Minimum Efficiency Index (MEI) is a metric used to measure the efficiency of a pump. MEI is particularly important for pumps exceeding 0.7 because it can help users save money on energy costs and reduce their carbon footprint.

What is the Minimum Efficiency Index (MEI) for Pumps?

The Minimum Efficiency Index (MEI) is a measurement of the efficiency of a pump. MEI is calculated by dividing the actual pump efficiency by the minimum efficiency for that type of pump. The minimum efficiency for each type of pump is set by the standards organizations such as the Hydraulic Institute and the European Union. The higher the MEI, the more efficient the pump is.

Why is MEI important for pumps exceeding 0.7?

MEI is particularly important for pumps exceeding 0.7 because it can help users save money on energy costs and reduce their carbon footprint. Pumps that exceed 0.7 are typically larger and more powerful, and they use more energy than smaller pumps. Therefore, even a small increase in efficiency can result in significant energy savings. In addition, using a more efficient pump can help reduce greenhouse gas emissions, which is an important consideration for many industries.

What are the benefits of using a pump with a high MEI?

  • Lower energy costs: Since a more efficient pump uses less energy, it can help users save money on energy costs.
  • Reduced carbon footprint: Using a more efficient pump can help reduce greenhouse gas emissions, which is an important consideration for many industries.
  • Improved reliability: A more efficient pump is likely to last longer and require less maintenance than a less efficient pump.
  • Better performance: A more efficient pump is likely to perform better, which can help improve overall process efficiency.

How can Crest Pumps help with MEI for pumps?

At Crest Pumps, we specialize in the design and manufacture of high-efficiency chemical resistant pumps. We understand the importance of MEI for pumps exceeding 0.7, and we can help our customers select the most efficient pump for their application. We offer a range of pumps with high MEI values, and we can provide expert advice and support to help our customers reduce their energy costs and carbon footprint.


How Crest Pumps Can Help

Lower energy costs

We offer a range of pumps with high MEI values, which can help our customers save money on energy costs.

Reduced carbon footprint

We understand the importance of reducing greenhouse gas emissions, and we can help our customers select pumps with the highest MEI values to achieve this goal.

Improved reliability

Our pumps are designed for reliability and long life, which can help our customers reduce maintenance costs and downtime.

Better performance

We offer pumps with high MEI values, which can help our customers improve overall process efficiency and performance.


The Minimum Efficiency Index (MEI) is an important metric for pumps exceeding 0.7. Using a pump with a high MEI can help users save money on energy costs, reduce their carbon footprint, and improve overall performance and reliability



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Contact us today for your chemical pump solutions that will minimise downtime and maximise energy efficiency.