Testing Steam Traps 1

A regular program of testing and maintaining steam traps is crucial for energy efficiency.  Unfortunately, in many steam plants the traps are ignored until a problem develops.  However, the cost of testing and maintaining the steam system is almost always much less than what is lost in wasted energy and repair costs.  Fuel, water, and chemical treatment costs can rise out of control with leaking steam traps.  Additionally, blocked or failed-closed traps will cause condensate to back up into heat exchangers and process equipment, which further leads to corrosion, leaks, and possibly freezing.  In the final analysis, many steam plants are operating at much higher costs than are necessary, and many maintenance personnel are playing catch-up and blowing their maintenance budgets fixing problems that could have easily been avoided.

The best place to start with a steam trap maintenance program is to have a steam survey done by a qualified steam specialist.  A proper survey will map out all the traps; test and note their condition; place an identification tag on the trap and note it on an accompanying spread sheet; make recommendations for repairs or replacement; and note any piping irregularities, misapplications, improper applications, and recommendations for efficiency improvements.  The initial survey acts as a baseline for a steam system PM program.  The best approach is to implement a regular testing schedule and replace failed steam traps as they are discovered.

The job of the steam trap is to remove the condensate from the steam system but not allow any steam to escape in the process.  Failed traps typically either blow through, allowing all steam to escape; fail closed, not allowing any steam to escape; or leak by the seat, not providing a good seal and allowing some steam, but not all, to pass through.  In terms of trap failure, these are the most common scenarios.  A common finding on steam trap surveys is misapplied traps, where someone replaced a trap with one that was not appropriate for the job.  In many cases a misapplied trap will not work well enough, or not at all if it’s not sized for the correct conditions.

I will cover the process for testing traps in the next entry in this series.

RJ Owen Associates has a complete selection of steam specialties and provides technical training, steam system surveys, technical service, and product support.

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