A desuperheater is designed to expand and reduce the pressure of the condensate line, separating steam and condensate. The steam is then introduced into a heat exchanger or deaerator to maximize its thermal energy, while the condensate is directed to a condensate tank for regular addition to the feedwater system. Primarily, it reduces pressure; if high-pressure steam is directly fed into a condenser, it can cause overpressure. This device helps to lower pressure, prevent overpressure, and also includes a temperature-reducing unit.

Mechanical (free floating ball, lever floating ball, inverted bucket) traps utilize the principle of buoyancy for operation. They can automatically distinguish between steam and water and are commonly used in situations requiring continuous drainage, with high flow rates, and where the drained water is collected and reused. The lever floating ball trap and inverted bucket trap have complex structures, while the free floating ball trap has a simple structure, does not leak steam, and is generally used for pipeline drainage or equipment drainage.

Thermal-mechanical (disc-type, pulse-type) trap valves utilize aerodynamic principles to switch valves by the pressure drop generated from the redirection of gas flow. They are suitable for applications with low flow rates, high differential pressures, and less stringent continuity requirements. These valves have a simple structure, exhibit pulsating leaks, and are generally used for drainage on pipelines.