How to Start and Stop Fresh Water Generator

Fresh water generator as name suggest is an machinery onboard which is used to generate fresh water for various purposes like drinking, washing etc. An engineer should know as how to operate this machinery effectively as water is a crucial fluid onboard.

This machinery uses the principal of evaporation of water at lesser temperature if done so in low pressure conditions. Thus we have a vacuum system in most of the FWG used on board. The jacket cooling water of main engine is used to provide the necessary energy for the evaporation. For detailed information on this please read: How Freshwater Generator Works

How to Start Fresh Water Generator

Here is the step by step approach for this and to make things easier we have given the diagram below.
1)     Open following valves:
·        Overboard Valve
·       Ejector pump inlet and outlet valve
·        Valve to bilges
2)    Close Following valves:
·        Air vent at the top of machine.
3)    In the control panel, you will see main switch, turn it on, which will result in power supply for the FWG operating panel. Make sure that Secondary alarm is in the off position, as it will keep on sounding in the beginning, as condition are not that stable.
4)    Now turn on the Ejector pump.
Diagram showing the pipe line arrangement
Alfa Laval Fresh Water Generator, Fresh Water Generator
 
5)    You can see slowly the vacuum developing inside the machine. We want it to be 98%, so wait for it. In site glass you can see the level of water inside the machine.
6)    After it is satisfied that we have 98% vacuum, it is time to adjust the heating water that will come from the main engine jacket cooling.
7)     You can see that there is a bypass arrangement provided for it on the extreme left. Right now it is in the open position, and the inlet and outlet of it to the FWG are closed. This means no water is coming to this machine.
8)   Open the outlet valve first and then the inlet valve.
9)    Now you will see change in the vacuum, it will decrease a little bit.
10) Slowl and steadily close the valve which is in the line to the jacket water cooler. This will result in more and more hot water being coming to the fresh water generator.
11)  At this time, see in the site glass as how much water level is there. We usually don’t let is drop below the half level of the glass.
12) At the same time, keep an eye on the vacuum. When things are stable, it is time to run the distillate pump.
13) In the beginning, we will let the fresh water to go in the bilges, so as to get the stable PPM. You can see that in the controlling panel.
14) You will start seeing that PPM is dropping slowly as time passes.
15)  One time will come, when it is lesser or equal to the required PPM.
Note: If the PPM is not coming down, you have to manipulate the amount of jacket cooler main valve open or close.
Salinity Alarm, Fresh Water Generator
16) Now on the secondary alarm system with the given PPM set value.
17)  Finally close the valve to bilges and open that to the fresh water tank.
18) You are generating fresh water as required.
19) Keep an eye on all the parameters for further 10 minutes.
20) You are done with the starting.

How to Stop Fresh Water Generator

1)   Now we will do everything in reverse of what we did during the starting.
2)    Close the valve to fresh water tanks.
3)    And stop the distillate pump, followed by turning off the secondary alarm system.
4)    Now slowly start opening the jacket water cooling valve. Wait for 5 minutes.
5)   Now close the inlet valve to the machine first, and then the outlet valve. This is to make sure that, no water remains in the lines after shutting down.
6)    You will see the water level in the sight glass will increase. Keep running the ejector pump for 15-20 minutes to cool down the plant.
7)    After this stop the pump and close the inlet and outlet valve.
8)    Close the overboard valve.
9)    Finally open the air cent if required.
10) You are done with the stopping of the machine.

Read here: What are the Reasons for FWG Salinity Alarm?

You Might Like to Read These Posts Too:

Ashish S

Hi there! Well I am not a writer, just writes what can help people-that's it. Interested in listening from you. Loves to talk about gadget, music, nerdy stuff and witty substance in the talks. A Good respect in heart- for web.

One thought on “How to Start and Stop Fresh Water Generator

  • May 22, 2017 at 4:13 pm
    Permalink

    hi sir.can you answer me some question.what reasons fresh water generator hight salinity alarm?.how many mercury in fresh water generator?.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Special Topics For You

Read these

Centrifugal Pump and Procedure for Overhauling Cen...  A centrifugal pump is used in large number on board ship and every marine engineer should know how to overhaul the centrifugal pump. Centrifugal ...
Black Out on Ship, Recovery and Actions to be take... Black Out on Ship is a common term which is used, when she loses all the power due to the failure of generators. Well  the reason of happening such...
What is Single and Twin Duct System in Air Conditi... This article discusses about the Single duct and twin duct system used on the ship to distribute the conditioned air. As we know...
Internal Combustion Engines Nomenclature, Performa... Know about all the engine performance parameters like IHP, BHP Volumetric Efficiency and also about MCR, astern output etc. These are the basic term...
What is Incinerator, Working and Maintenance Requi... This article discusses about the working and construction of an incinerator. The incinerator is used on board ship to burn the waste products gene...
Best Books for Studying Marine Engineering Topic W... Marine Engineering is that branch of technical education that covers, mostly the technical aspects of marine machinery. It includes marine engines, ...
Construction and Working Principal of Incinerator One can absolutely say that the incinerator is like a boiler and the only difference is that in this machinery we do not generate the steam. Cons...
What is Shipboard Ventilation, and Low and High Ve... In this article you will get to know about the shipboard ventilation system used on ship. Furthermore, the two system namely: high and low veloci...
error: Content is protected !!