Armstrong Thermostatic Steam Traps are available with balanced-pressure bellows or wafer-type elements and are constructed in a variety of materials, including stainless steel, carbon steel and bronze. These traps are used on applications with very light condensate loads.
Thermostatic steam traps operate on steam’s temperature difference from cooled condensate and air. Steam increases the pressure inside the thermostatic element, causing the trap to close. As condensate and non-condensable gases back up in the cooling leg, the temperature begins to drop, and the thermostatic element contracts and opens the valve.
The amount of condensate backed up ahead of the trap depends on the load conditions, steam pressure and size of the piping. It is important to note that an accumulation of non-condensable gases can occur behind the condensate backup.
NOTE: Thermostatic traps can also be used for venting air from a steam system. When air collects, the temperature drops and the thermostatic air vent automatically discharges the air at slightly below steam temperature throughout the entire operating pressure range.