A water production unit on board.

Principles of Operation:

The vacuum necessary for the evaporation is established and maintained by the combined air/brine ejector. Cooling water pump. The feed water enters the evaporator section through an orifice, and distributed into every second plate channel (evaporation channels).
The jacket water distributed into the remaining channels this transferring its heat to the feed water in the evaporation channels. Having reached the boiling temperature the feed water undergoes a partial evaporation. The mixture of generated steam and brine enters the separator vessel, where the brine is separated from the steam. The brine is extracted by the combined air/brine ejector.
Having passed a demister (filter) the steam enters every second plate channel in the condenser section The sea water supplied by the combined ejector/cooling water pump distributes itself into the remaining channels thus absorbing the heat transferred from the steam during the condensation. The produced fresh water is extracted and transferred to the tank by the fresh water extraction/transfer pump. On the delivery side of the pump an electrode unit is fitted, which, together with the salinometer, continuously checks the salt content of the produced water.

The FWG consists of the following main components and their specific functions:

Separator Vessel

The separator vessel separates the produced steam from the brine.

Evaporator Section

The evaporator section consists of a plate heat exchanger, and is enclosed in the separator vessel.

Condenser Section

The condenser section like the evaporator section consists of a plate heat exchanger, and is enclosed in the separator vessel.

Combined Air/Brine Ejector

The combines air/brine ejector extracts air and brine from the separator vessel.



Related Terms

MULTIPLE-EFFECT EVAPORATOR

An evaporation system in which a series of evaporator bodies are connected so that the vapors from one body act as a heat source for the next body.

AUTOMATIC FROST CONTROL

Control which automatically cycles refrigerating system to remove frost formation on evaporator.

AUTOMATIC DEFROST

System of removing ice and frost from evaporators automatically.

BLAST FREEZER

Low-temperature evaporator which uses a fan to force air rapidly over the evaporator surface.

SUPERHEATER

Heat exchanger arranged to take heat from liquid going to evaporator and using it to superheat vapor leaving evaporator.

DEFROST CYCLE

Refrigerating cycle in which evaporator frost and ice accumulation is melted.

SUCTION SIDE

Low-pressure side of the system extending from the refrigerant control through the evaporator to the inlet valve of the compressor.

DEFROSTING

Process of removing frost accumulation from evaporators.

DRY SYSTEM

Refrigeration system which has the evaporator liquid refrigerant mainly in the atomized or droplet condition.

EVAPORATOR FAN

Fan which increases airflow over the heat exchange surface of evaporators.

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