The ultimate purpose of the steam trap is to allow the Condensate (water formed when steam condenses) and air to be discharged from the steam system while preventing the loss of live steam.
The most common application for regulating valves is for reducing the downstream pressure of Steam, Water, as well as other liquids and gases that are flowing thru a pipe or system.
Control Valves are used to regulate the flow of steam, water or other fluids to maintain a process such as heating water with steam or cooling down a process using chilled water.