Starting And Stopping Procedure Of FreshwaterGenerator

 Starting

> Open seawater ejector pump suction, discharge and overboard valves. 

> Start the ejector pump, discharge pressure must be more than 3bar.

> Wait for the vacuum to build up inside the fresh water generator shell. (About 92 % vacuum).

> Open the feed water valve to feed seawater to the evaporator. Adjust the feed water pressure. Normally marking is provided on the pressure gauge for desired feed water pressure.

 > Open main engine jacket cooling water inlet and outlet to the evaporator gradually.

> Open the air vent clock at the top of the evaporator to make sure the evaporator is filled with jacket cooling water. Air must be purged out if any.

> Throttle the jacket cooling water by-pass valve

> Switch on the salinity alarm panel for measuring the purity of the freshwater produced.

 > There will be a sight glass provided at the suction line for the distillate pump. Make sure condensed water is coming to the suction line. 

> Start the distillate pump and open discharge valve to lead generated water to specified storage tanks.


Checks during running

> Through the sight glass provided in the evaporator shell, observe flashing of water.

> Also, check for the brine level inside. It should not be too high or too low.

> Shell temperature must be around 50 deg cel.

> Make sure the shell vacuum is more than 90% from the vacuum gauge.

> Check seawater inlet and outlet temperature to the condenser.

> Ensure seawater pressure at air ejector inlet more than 3 bars.

> Check for distillate pump pressure and water flow meter.

> Check salinity of fresh water produced.

> Check level and flow of dosing chemicals.

 > Check ampere of ejector pump and distillate pump motor.


Stopping

> Slowly open bypass valve for main engine jacket cooling water.

> Ensure that main engine jacket cooling water temperature is within normal limits.

> Close jacket cooling water inlet and outlet valves for the freshwater generator respectively.

> Close the feed water chemical dosing valve.

> Stop the distillate pump and shut discharge valve.

> Switch off the salinity meter.

> Close the filling valve to the freshwater tanks.

> Wait for evaporator shell temperature to drop below 50 deg cel.

> Close the feed water valve to the evaporator.

> Stop ejector pump. Shut the fresh water generator overboard valve.

> Open the vacuum breaker valve to make shell side pressure equal to atmospheric pressure.

> Open the drain valve of the evaporator to drain all the seawater from the fresh water generator.

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