Steam Distribution Piping: Low spots
The steam distribution piping must be pitched properly to avoid low spots. The steam piping loses heat by radiation, causing condensate to form. This liquid water accumulates on the inside surface of the pipe wall. During periods of low flow this water runs by gravity and will accumulate in any low spot. When the flow increases, velocity causes waves toform at the surface of the accumulated condensate. When one of the waves touches the top of the pipe, a slug is formed, which
is driven at high velocity downstream by the steam pressure differential. Because the steam velocity can accelerate these slugs to 60 mph or greater, drip traps, and even separators have difficulty catching all the condensate and draining it from the steam main.
Steam traps are needed at low spots or risers in a steam system to remove condensate (liquid water) that forms during the process of steam generation and distribution.
When steam is generated, it contains a certain amount of water vapor. As the steam travels through pipes and equipment, it cools down and loses heat energy. This causes the water vapor to condense back into liquid form, known as condensate.
If condensate is allowed to accumulate in low spots or risers, it can cause several problems. Firstly, condensate takes up space in the pipes, reducing the effective flow area for steam and hindering the efficiency of the system. Secondly, condensate can cause water hammer, a phenomenon where the rapid movement of condensate can create pressure surges that can damage equipment and pipes. Lastly, condensate may contain impurities that can corrode the system or affect the performance of downstream equipment.
Steam traps are designed to automatically remove condensate from the steam system while preventing the loss of steam. They work by opening to allow condensate to drain out and closing to prevent the escape of steam. By installing steam traps at low spots or risers, condensate can be effectively removed, maintaining the efficiency and integrity of the steam system.