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Seawater Cooling for Refrigeration Engineers - Self Priming Centrifugal Pumps

Download Case Study

Customer: Refrigeration Engineering Company

Application: Refrigeration cooling pump 

Equipment Supplied: 2 x Self-priming Centrifugal Pumps

Location: UK

Equipment Supplied

2 x  Azcue SP-MN close coupled centrifugal pumps with air priming ejectors

  • Application: Refrigeration Cooling Pump
  • Fluid: Sea Water
  • Temperature: Ambient
  • Flow: 500m³/h
  • Total head: 16.4 m
  • IE2 Motor: 30 kW, 400V, 3Ph, 50 Hz, 1450 rpm
  • NPSHr 3.68 m, Isol/Prot. F/IP-55
  • Mechanical Seal
  • Bronze Pump Casing
  • Bronze Impeller
  • S/discharge Ø 200/150
  • St. Steel Shaft
  • Impeller Size Ø269


A UK based engineering firm contacted us looking to purchase a centrifugal pump to install on their new gas refrigeration system as a sea water cooling pump. The aim of this new system was to demonstrate to their customers how much energy they could potentially save by upgrading their dated refrigeration setup. They were struggling to find a self priming centrifugal pump that could handle the requested very high flow rate of 8,300 l/min, as typically centrifugal pumps usually see flow rates of only around 5,000l/min.

Self Priming Centrifugal Pump for Cooling

A reliable pump was vital for this system as the cooling pump would be working 24 hours a day to keep the heat exchanger cool as the refrigeration gas was circulating through it. If the pump went down for even a second, a true reflection of the system savings would not be accurately demonstrated.

Key challenges:

  • Extremely high flow rate required
  • Operation required 24 hours a day
  • Downtime to be completely avoided


Due to their efficiency pumping water, we specified Azcue MN-VP centrifugal pumps; a model capable of handling the required 8,300 lpm flow rate. This centrifugal water pump has a unique feature whereby it has an air operated self priming pump attached to the main pump which starts intermittently operated via a pressure switch. This ensures a completely automatic priming system should there be any loss of prime, meaning no need to manually operate the pumps.

We supplied these self priming centrifugal pumps in bronze, ensuring all wetted parts that come into contact with the seawater are non-ferrous and will not corrode overtime.  

As avoiding any downtime was extremely important to the engineering firm, we specified a second pump as a backup to ensure continuous operation should the main cooling pump require maintaining or worst case fails.This duty / standby arrangement is the safest and most efficient way to ensure the refrigeration system is never down.

Castle Pumps are fully accredited to enable you to buy with confidence. Our accreditation includes: Our accreditation A division of the CTS Group, Part of Flow Max Ltd.