The first method used to control condensate discharged was hand operated.  An operator would use a hand valve positioned on the discharge line reducing or increasing flow.  While this was considerably better than an open discharge line, it was still quite difficult to determine if the valve is open just the right amount.  The valve wide open would lose valuable live steam; if not open enough, condensate would back up, filling the steam space.  In addition, any change in the rate of condensate forming ,or change in steam pressure also caused the loss of live steam or the backing up of condensate, whichever may be the case.  In all cases, there was substantial efficiency loss.

 

TODAY’S GENERATION OF MECHANICAL STEAM TRAPS – A SIGNIFICANT ENERGY IMPACT

Conventional mechanical steam traps remove condensate cyclically. They are designed to open in the presence of condensate and close in the presence of steam utilizing internal floats, buckets, bimetal, bellows or discs. Properly operating mechanical steam traps cycle several times a minute – over 2 million times a year on 24-hour-a-day processes. Consequently they wear, leak and eventually fail.

 

 

 

 

Although a steam trap is physically a small piece in any boiler-steam system, its impact is significant. Even a small leak can cost thousands of dollars each year in wasted fuel. It is common to find 15 to 30 percent of steam traps inoperative within a facility.  In one large government-owned facility, a comprehensive steam trap survey was conducted to identify each trap in the system, characterize its in-service performance, and determine the total cost of the wasted steam energy. Of the 910 traps surveyed, 207 traps were found to be wasting a total of 4,783 lb of steam per hour at an annual cost of more than $60,000. (R.H. Brained, G.R. Govindarajan, G.P. Haynes, and B.D. Warnick, ORNL Steam Trap Survey, Lockheed Martin Energy Systems, Inc., Oak Ridge, Tennessee, 1996.)

 

 

 

For a steam trap system to operate efficiently, each trap must remove condensate as it forms without releasing valuable steam. Malfunctioning  mechanical traps represent a significant source of wasted energy! Mechanical steam traps can either fail open or closed. If failed open, steam leaks from the system, wasting fuel and energy and reducing the amount of steam available to end-use applications by as much as five percent. A failed open, a mechanical steam trap can lose between 50 to 100 lb of steam per hour. If failed shut, on the other hand, condensate builds-up and reduces system capacity. More important is "water hammer," a problem in which condensate moving through distribution pipes causes damage as it "hammers" into curves, protrusions, and corners.