You have probably heard many times that ‘less is more’. Well, that is not always the case. When it comes to choosing a pump, especially a positive displacement pump, more information is surely better. Many variables have a direct impact on how a pump will function and how long it would last for. If you are unsure of how to choose the most appropriate pump or the information you need to know before you contact any vendor, you are not the only one. This article has gathered a list of the foremost things you need to know when choosing a pump to help in guiding you through the entire process.

1. Properties of process liquid

What kind of liquid do you intend getting the pump for? Some properties of process liquid that have to be taken into consideration before choosing any pump include;

  • The viscosity of the liquid.
  • Specific gravity.
  • Solids present and their concentration.
  • Non-abrasive or abrasive.
  • Temperature.
  • Vapour pressure.
  • Shear sensitivity.

2. Materials of construction

What are the materials of construction that are compatible with the process liquid or any of the other varying liquids that the pump could come in contact with? There are chemical compatibility charts that are made available to assist you in identifying the most ideal materials of construction for your potential pump.

3. Is the pump crucial to plant operations?

In crucial applications, when downtime isn’t even an option, heavy-duty, more costly pumps with special features could be chosen. There are lots of varying positive displacement pump types that could be suitable here. If pumps can be taken out of service to be maintained, then less costly options can be considered.

4. Conditions of pump inlet

You surely wouldn’t want a pump starved. The available NPSH (system net positive suction head) is computed by knowing the pressure of the pump inlet and that of the liquid-vapour. Always ensure that the NPSHA exceeds the NPSH that is required.

5. Pump Environment

If the pump will be outdoors, special freezing temperature installation or construction considerations might have to be made. If the environment features explosive dust or vapour or is hazardous, the special motor features would be needed. These are only a couple of examples of environmental conditions to take into consideration.

6. Availability of power source

The most basic source of power in the US is 60 Hertz/115 to 230 Volts/1-phase or 60Hertz/230 to 460 Volts/3-phase. Particular motors could be specified for operations outside the US or via the utilisation of DC batteries. Pressurised hydraulic oil or compressed air could also be utilised for power.

7. Pressure and flow rate

Your total volume and understanding the length of time you have to convey the fluid is what determines the flow rate. Pump differential pressure could be computed via the knowledge of the size of the pipe (fittings and length), system equipment (valves, filters, and so on), static lifts, and friction losses.

In conclusion, by fully understanding these listed factors, you are getting yourself armed with the knowledge that is needed to choose the most ideal pump, particularly when you need a positive displacement pump. Irrespective of the application, you could feel quite confident with your next process of pump selection.