Steam trap

A steam trap is a device used to discharge condensate and non-condensable gases with a negligible consumption or loss of live steam. Most steam traps are nothing more than automatic valves. They open, close or modulate automatically. The three important functions of steam traps are:

The simplest form of steam trap is a disc or short solid pipe nipple with a small hole drilled through it installed at the lowest point of the equipment. Since steam condensate will collect at the lowest point and live steam is about 1200 times greater in volume than this hot liquid, condensate is effectively removed and steam is blocked. However, the vast majority of steam traps in current operation are of the mechanical or thermostatically operated design.

Mechanical and thermostatic steam traps basically open when condensate and inert gases need to be removed, and close when all the condensate is removed. The process repeats when new steam is condensed again and ready to be drained.

Steam traps work best when sized specifically for the application they are used on. Generally, it is better to oversize, as they will still discharge condensate when present and close or obstruct for live steam. However an oversized steam trap may wear quickly, waste energy (use steam), and if drastically oversized can cause process issues.

Steam traps can be split into four major types:

There are 4 types of steam trap:

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