What Is A Steam Trap?

- Sep 08, 2020-

The steam trap is a valve that automatically discharges condensate and non-condensable gas to block steam leakage. In industry, steam is often used to heat products or as power for mechanical equipment. In this case, a steam trap is required to ensure that there is no leakage of steam.


"Trap" is defined in valve terminology: a device that can automatically drain condensate from equipment or pipes without external help.


What is the purpose of installing a steam trap?

Steam is the gas formed after water is heated and evaporated. In order to form this process of evaporation, water molecules must absorb enough energy, and then the molecules (hydrogen bonds, etc.) will break. This energy conversion from liquid to gas is called "latent heat".


Steam basics: The heat exchanger uses the latent heat of steam to convert heat energy to the product, but when the steam completes the heating task (that is, loses the latent heat), the steam will condense to form condensate. In other words, condensed water does not have the ability to heat objects like steam. The heat exchange efficiency will be affected, so whether in the steam pipeline or the heat exchanger, the condensate must be quickly discharged.


Reasons for the necessity of steam traps


What are the problems with normal valves?

You may sometimes think that other regulating valves can be used to replace the traditional steam traps, and the condensate discharge can be achieved by manually adjusting the valve opening.


This is theoretically possible. However, the conditions and circumstances that need to be met are very extreme. Therefore, in actual operation, it is not a practical solution.


The biggest problem is how to set the valve opening. If it is set to a fixed opening, it cannot be adjusted with fluctuations in the rate of condensate formation. In fact, the amount of condensate formed in the same system is not fixed. As far as the equipment is concerned, the amount of condensate at startup is different from that under normal working conditions, and fluctuations in product load will also affect the amount of condensate. Similarly, as far as the steam pipeline is concerned, the amount of condensate is also related to the outdoor temperature and weather.


If the equipment cannot withstand the fluctuations caused by the load of condensate, the condensate needs to be discharged immediately. Conversely, the accumulated condensate in the equipment or pipes will affect the heat exchange efficiency. On the other hand, when the load of condensate is reduced, steam leakage will occur, resulting in waste of steam.


Reduce heat exchange efficiency and waste steam


Steam traps can be applied to a variety of different mechanical devices

Various types of steam traps (divided according to their working principles) have been developed to automatically discharge condensed water and non-condensable gases. At present, the most common principle is to use temperature difference, specific gravity difference and pressure difference. Each type of steam trap has advantages and applications.