The clouds of steam that billow up from the open discharges of thermodynamic traps are often mistaken for live steam loss, but the fact is that TD traps do not waste steam and are actually energy efficient.
It is often assumed that thermodynamic steam traps waste steam however such is not the case. Upon closely observing thermodynamic traps discharging to atmosphere its open/closed action will be obvious. There is a period when water and steam are violently discharged, followed by a period of virtually nothing. Each period will last a variable number of seconds depending on the operating conditions.
Say, if a steam system operates at 7 Barg, a Thermodynamic steam trap will discharge condensate at 170°C. As soon as this condensate is exposed to atmospheric pressure it can’t exist as a liquid at 170°C as the maximum temperature of water at atmospheric pressure can be 100°C. The excess heat is used to boiler a portion of the condensate into steam and this is called flash steam. The remaining condensate can now exist in the liquid state at 100°C. Because flash steam looks just like live steam, it’s not surprising that all this steam is so often presumed to be leakage of live steam.
So long as a thermodynamic trap has a clearly defined “closed” period, with virtually nothing being discharged, the trap will be working OK and not leaking steam. All traps produce flash steam, but with thermodynamic traps, it’s concentrated into the brief “open” periods of the trap’s cycle, whereas a trap that has a continuous discharge (e.g. a ball float ) will have its flash steam evenly produced all the time, therefore appearing at any given moment to be much less.
Thus, you can be confident that a properly operating thermodynamic trap, i.e., one with a distinct open/closed action, is not wasting or leaking steam and is the perfect choice for main line applications.