Water Eductors for Freshwater Generators

Fresh Water is an essential requirement on ships that sail the high seas. Due to lack of any source of fresh water while out in the ocean ships generate fresh water by distillation od sea-water. These machines are known as fresh water generators. The ship’s pumps pump sea-water to the freshwater generator
To reduce energy requirements fresh water generators use waste heat from the ship’s engines or boiler to distil sea-water.
At normal atmospheric pressure water evaporates at 100°C, but waste heat is generally available at 70~80°C on most ships. Hence to utilize the waste heat distillation is performed out at ~50°C and for that the distillation is carried out under vacuum (approx. 120mbar)

Water Eductors utilize the energy in pumped water for their operation and can be put to use to create vacuum conditions at its suction inlet.

Water Eductors are essentially Liquid jet Vacuum Ejectors that operate on the basis of the jet Venturi principle.

In a fresh water generator the water eductor uses the incoming sea-water for its operation and creates vacuum for the distillation. The sea-water + vapour mixture discharged from the Water Eductor Outlet is reinjected into the distillation tanks.

A Water Eductor or Liquid jet Vacuum ejector can develop ultimate vacuum upto 30 Torr i.e 40mbar.
The Water Eductor commonly operates with wide range of motive liquid pressure from 2.5 bar(a) to 7 bar(a).

Water Eductors are available in Bronze which offers excellent corrosion resistance against sea-water / brine.

Water Eductors are an integral part of a Fresh water generator because of their inherent characteristics
• Ability to tolerate liquid carryover in suction stream, ensures that the Water Eductor can handle the sea-water + vapour mixture coming from the distillation tanks.
• Water Eductors do not contain any moving parts and have large internal passage areas, hence are not vulnerable to liquid entry or clogging by solid particles.
• As they have no moving parts, maintenance requirements are very less. Also it reduces largely the risk of abrupt breakdowns, helps in maintaining the regular production schedule
• Sea-Water at 2.5~7 bar(a) is a commonly available on Ships and hence no additional infrastructure is typically required.