High temperature steam is used in the engine room for several purposes such as heating fuel line and fuel tanks. Water hammer is a common phenomenon that occurs in steam lines because of water getting stuck in the pipes. Let’s find out how water hammer takes place and what can be done to avoid it.
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How Water Hammer takes place?
When the steam lines are shut after use, water gets accumulated in the steam pipes mainly because of condensation of the trapped steam. When high temperature steam is again passed through the lines having water, the steam comes in contact with the water and pushes the water down the line.
As the steam comes in contact with water, it eventually condenses and creates a vacuum, which forces the water towards the opened valve at high velocity. The water then hits the valve with high speed, damaging or breaking the valve or piping completely. Valve fracturing because of water hammer has resulted in to disastrous accidents in the past including loss of lives. It is therefore necessary to take every possible step to reduce the effects of water hammer.
How to Prevent Water Hammer?
The most important way to prevent water hammer is to remove the water from the steam lines before passing the steam again through them. Water is removed from the steam lines using drain connections.
All the water should be drained out to make the lines clear. Once this is done, the steam valve should be opened very slightly (cracked open) to heat the line and to bring it to working temperature. This also ensures that the condensate formed due to inlet of steam is removed through the already opened valve. The drain outlet should be continuously checked to ensure that all water is drained out.
Avoid Sharp bends in the steam pipes as sharp bends will help the steam to condense more.
When all the water is removed and the noise from the drain changes to steam blow, the steam valve should be opened further. This process has to be slow and extremely gradual.
After sometime the drain valve should be completely closed and the steam valve to be completely opened. This method prevents water from accumulating in the pipes and eventually stops water hammer.