A steam trap is a device used to discharge condensates and non-condensable gases with a negligible consumption or loss of live steam. Steam traps are nothing more than automatic valves. They open, close or modulate automatically.[1] The three important functions of steam traps are:
Discharge condensate as soon as it is formed (unless it is desirable to use the sensible heat of the liquid condensate)
Have a negligible steam consumption (i.e. be energy efficient)
Have the capability of discharging air and other non-condensable gases.