What Is A Steam Trap?

- Apr 17, 2020-

Steam trap is a kind of valve which can automatically discharge condensed water and non condensable gas to block steam leakage. In industry, steam is often used to heat products or power mechanical equipment. In this case, a steam trap is required to ensure that there is no leakage of steam.

"Drain valve" is defined as a device that can automatically discharge condensate from equipment or pipeline without external help.

What is the purpose of installing steam traps?

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

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

The necessity of steam trap

What's the problem with a normal valve?

It may sometimes be thought that other regulating valves can be used instead of the traditional steam traps, and the condensate discharge can be achieved by manually adjusting the valve opening.

Theoretically, it is possible. However, the conditions and circumstances that need to be met are very extreme. So in practice, it is not a practical solution.

The biggest problem is how to set the opening of the valve. If it is set to a fixed opening, it cannot be adjusted with the fluctuation of the speed 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 during startup is different from that under normal working conditions, and the fluctuation of product load will also affect the amount of condensate. Similarly, in the case of steam pipelines, the amount of condensation is also related to the outdoor temperature and weather.

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

Reduce heat exchange efficiency and waste steam

The steam trap can be applied to various mechanical devices

Various types of steam traps (according to the working principle) have been developed to automatically discharge condensate and non condensable gas. At present, the most common principle is to use temperature difference, specific gravity difference and pressure difference. Each type of steam trap has its advantages and applications.