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Bilge Injection Valve

Bilge Injection is a valve that enables the engine room bilges to be pumped out directly overboard in the event of an emergency such as flooding. The valve is normally fitted to the end of a branch connection with the main sea water suction line. This enables large main seawater cooling pumps to be used as a bilge pump in an emergency.

Emergencies like fire and flooding involve the use of seawater. If there is a fire, seawater is the biggest resource of water available in the sea. Similarly, if it involves flooding of the engine room, cargo spaces or any other place on the ship for that matter; you would again require pumping the sea water out of the ship. In both these cases, you require pumps. 

There are two valves in close proximity namely main injection valve and bilge injection valve. Both of them have their own independent controls. The diameter of the bilge injection valve is kept nearly 66% of the main valve diameter which draws water directly from the sea through the grid. There is a SOLAS requirement that the diameter of this injection valve is at least 2/3 times the main suction, though it can be more also.The spindles of the sea inlet and injection valves shall extend well above the engine-room platform.

Hence the injection valve is an arrangement where the main sea chest can be bypassed in case of emergency so that instead of the sea, water gets drawn from within the ship itself.

There is a strainer attached to the bilge injection valve and the pump used for this valve is normally the largest seawater pump (or pumps) available in the engine room. Hence this valve is used to suck sea water from one of the lowest points in the engine room.  This basically means that when you need to remove a lot of water from the ship, you simply need to open this valve and run the big pump's.

Prior to opening up of the bilge injection valve always take approval or permission from the chief engineer of the vessel.

Checks and Precautions:
  • Emergency situation can arise anytime (that’s why is called emergency) so it would not be a good idea to find out that your valve is stuck due to rust or non-operation. Hence it is a good practice to check for the operation as a matter of routine.
  • The space near the injection valves should be kept clear of all obstacles since normally one would rush to open the valve in an actual emergency, and hence should be minimal obstacles in the space around the valve.
  • Not only should the valve be easily approachable and operational, but it also needs to be checked regularly for actual suction and operation. This can be done occasionally by actually running the pump and trying to draw out water from the bilge spaces uses this valve.
  • The valves should be clearly marked since people do get confused in emergency situations and you certainly don’t want to be opening some wrong valve at such a critical time


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