Bellows Steam Trap Working Principle

The bellows steam trap is a steam-trapping and water-discharging device operating on the thermostatic principle, with its core actuating element being a metal bellows filled with special liquid. This device realizes automatic opening and closing of the valve by sensing changes in medium temperature: when low-temperature condensed water appears in the pipeline, the valve opens to discharge water; as the temperature rises, the liquid in the bellows vaporizes to push the valve core to close, completing the steam-trapping function before the condensed water reaches saturation temperature.

Bellows Steam Trap Working Principle

• Startup Phase: During the initial operation of the equipment, the pipeline contains low-temperature condensed water, the liquid in the bellows remains in a liquid state, and the valve is fully open for water discharge.

• Temperature Response: When the temperature of the condensed water rises to the set threshold (15℃ or 30℃ below the saturation temperature), the liquid in the bellows vaporizes to generate pressure, pushing the diaphragm to drive the valve core to close gradually.

• Steam-Trapping Phase: The valve closes before the condensed water fully reaches the saturation temperature, effectively preventing steam leakage, and reopens for circulation until the temperature drops.

Below is the animated working principle of the bellows steam trap：