Thermostatic Steam Trap

Fangwen 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 operation

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.

Thermostatic Ball Float Steam Trap

All the benefits detailed here have been designed into Fangwen Thermostatic Ball Float Steam Trap through long experience in the manufacture of pressure float-type traps. They assure you of optimum operating efficiency for long periods with minimum trouble.

How they work

Thermostatic Ball Float Steam Traps are mechanical units that operate on both density and temperature principles. The float valve operates on the density principle. A level connects the ball float to the valve and seat. Once condensate reaches a certain level in the trap, the float rises, opening the orifice and draining condensate. A water seal formed by the condensate prevents live steam loss

Since the discharge valve is under water, it is not capable of venting air and non-condensables. When the accumulation of air and con-condensable gases causes a significant temperature drop, a thermostatic air vent in the top of the trap discharges them. The thermostatic vent opens at a temperature a few degrees below saturation, so it's able to handle a large volume of air-through an entirely separate orifice-but at a slightly reduced temperature.

Fangwen Thermostatic Ball Float Steam Traps are unique in their super heavy duty construction. Fangwen uses high quality ASTM A48 Class 30 cast iron or ASTM A216 WCB cast steel-normally found in pressure vessels rated to 250 psi (17 bar) or 465 psi (32 bar). Internal mechanisms are made from stainless steel and are heavily reinforced. No brass cotter pins here. Valves and seats are stainless steel, hardened, ground and lapped to withstand the erosive forces of flashing condensate.

Why go to all this trouble for traps normally recommended for low-pressure, modulating service? The operative word here is modulating. Modulating pressures mean widely varying loads, thermal cycling and high air and non-condensable gas loads.

In other words: tough service. Inferior, lightweight construction in this kind of service is a mistake waiting to happen. Trap failures on modulating pressure may lead to water hammer, corrosion and even damage to heat exchangers.