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Reverse Osmosis/Desalination for Private Boat - High Pressure Plunger Pump

Customer: Private Boat 

Application: On board seawater desalination

Equipment supplied: High pressure triplex plunger pump

Location: Germany

Case Study - Desalination Pump for Reverse Osmosis

Equipment supplied

1 x CAT Plunger pump

  • Supply includes 3CP1221 pump, motor, flexible coupling and bellhousing
  • Motor is 1.1 kW 6 Pole 400/3/50 IP55 TEFC.
  • For use in an indoor safe area
  • Pump Duty: 8.8 litres/minute at 35 Bar.
  • Liquid: Sea water
  • Material: Stainless steel
  • Temperature: Ambient
  • Inlet: c2 metres head is recommended.
  • Drive: 0.9 kW absorbed power at a pump speed of approximately 960 rpm.


Castle Pumps were contacted by an owner of a private boat who was installing a new reverse osmosis system onboard their vessel for the conversion of sea water into portable fresh water. The process, referred to as desalination, required a high pressure pump to force the seawater through a porous membrane that separates pure water from salt, minerals and ions. This particular desalination pump was needed to transfer sea water at a duty of 8.8 L/min at 35 Bar.

Key challenges:

  • Very high pressure capabilities
  • Able to handle the corrosive nature of seawater
Plunger Pump


Thanks to our wealth of experience with providing seawater reverse osmosis pumps; we have access to a high quality brand of plunger pumps that are widely used within desalination systems. We selected a CAT reverse osmosis water pump fitted to a 1.1Kw 6 pole motor to achieve the required duty of 8.8 L/min at 35 Bar. The desalination pump was supplied in stainless steel, a material that is able to handle the corrosive nature of seawater. 

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.