Steam traps and steam trap stations

Features and Usage Limitations of Float-Type Steam Traps and Inverted Drum-Type Steam Traps – Zhong Yuyu, Technical Department, Hangzhou Watt Energy Saving Engineering Co., Ltd. Mechanical steam traps operate by taking advantage of the density difference between condensate and steam; since the densities of these two fluids differ significantly, the buoyancy generated is also greatly different. Mechanical steam traps function by using a float or buoyant element to detect this difference in buoyancy between steam and condensate. It can be seen that the free-floating ball type steam trap, the Watt FQ lever-ball type steam trap, and the Watt DT inverted drum steam trap all belong to the mechanical type of steam traps. It can be seen that the basic principle behind the design of mechanical steam traps is based on buoyancy; therefore, within the design pressure range of the steam trap (the maximum operating pressure), even if there are slight variations in pressure (steam pressure) or temperature (the temperature difference between steam and condensate, as well as the temperature of the condensate), its performance is not affected at all. For this type of steam trap, its discharge capacity is determined by the steam pressure (operating pressure) and the area of the valve throat (effective area of the valve seat). Mechanical steam traps share the following common characteristics and features: Mechanical steam traps are particularly suitable for applications with high flow rates. However, since a float mechanism is required, its size is larger compared to other types of steam traps; using a lever mechanism can effectively reduce the volume. Since mechanical steam traps rely on buoyancy to move the float up and down, the body must be installed horizontally, although this requirement is not extremely strict. If the pressure applied exceeds the design pressure of the steam trap, the trap will not open and thus cannot remove the condensed water. When used with superheated steam, the condensed water inside the steam trap may evaporate again, causing the float to drop and leading to steam leakage; the check valve at the front end can help mitigate some of the effects of superheating. In cold or frozen areas, insulation is necessary to prevent the condensation water inside the steam trap from freezing. Mechanical steam traps must be installed with care, avoiding areas with severe vibration. Any mechanical steam trap will experience rapid wear in its structure where the conical or arc-shaped valve element engages with the valve seat, once this is known. When the back pressure of a mechanical steam trap is abnormally high, it will not leak steam either, but the discharge volume of condensate will inevitably decrease.