Major Types of Steamtraps

Steam engines are installed with steamtraps to keep steam from escaping and condensate from infiltrating the system. As steam enters the engine from the boiler full of condensate, it passes through the engine to create mechanical work. From the boiler, both steam and condensate enter the system and act on the process of energy generation. However, condensate is regarded as an invaluable material and can reduce the efficiency of the process.

Steamtraps are extremely helpful in providing the engine with pure steam. It has a mechanism that inhibits the entry of substances heavier than steam like condensate. Generally, steamtraps are valves and like all other valves, it allows fluid to pass through to a destination at a regulated flow. However, this device does not only control the amount of fluid to flow through the system but also prevent unnecessary materials to join.

There are three major types of steamtraps categorized according to the mechanism of discharging condensate and trapping steam: mechanical, thermostatic, and fixed-orifice. The reason for the various types of steamtraps is the variation in the amount of steam conveyed. Most boilers produce fluctuating amounts of steam that makes some steamtraps designed for a constant amount of steam and condensate to be unproductive.

Traditional steamtraps are mostly mechanical traps. They consist of an orifice and a weight. The condensate enters the trap first and fills the body of the valve at a certain level. The steam comes in next and produces pressure to close the valve at the bottom of the trap. When sufficient condensate form in the trap, the weight begins to float and opens the orifice to discharge the condensate and other gases.

Modern steamtraps are thermostatic or operate through change in temperature. Unlike mechanical traps, this type of trap does not use pressure to move the weight at the bottom. Instead, a bimetal strip holding the weight expands as the temperature in the trap increases and allows the weight to float to create a pressure that will push the condensate towards the orifice.

The oldest type of steamtraps is the fixed-orifice or the non-weight traps. The orifice of this trap is kept open to allow the condensate to freely move towards the discharge pipe. Fixed-orifice traps are no longer used for general application because of its tendency to fail when large amounts of steam are reduced to condensate while being transmitted to the engine. This is only used for standard steam distribution applications.