The bellows steam trap (steam pressure balanced type) is an advanced energy‑saving steam trap widely used internationally. It features extremely sensitive response. High‑temperature condensate is maintained in front of the valve during operation without steam leakage, delivering remarkable energy‑saving performance.

The advantages of bellows steam trap include automatic air venting, compact size, freeze resistance, and installation at any position. It is easy for maintenance; inspection, repair and component replacement can be completed on‑site on pipelines. It achieves high back‑pressure rate up to 80%. The robust bellows ensures long service life. It is widely applied for steam main pipelines, steam tracing networks, instrument tracing and small heating equipment for steam blocking and condensate drainage.

Working Principle

The main actuating component of bellows steam trap is a metal bellows filled with liquid whose vaporization temperature is lower than the saturation temperature of water. At equipment startup, low‑temperature condensate appears in the pipeline, the liquid inside the bellows remains condensed and the valve stays open. As condensate temperature rises gradually, the filling liquid inside the bellows evaporates, internal pressure increases, and the diaphragm drives the core towards closing position. The trap closes completely before condensate reaches saturation temperature. The bellows opens and closes the valve according to steam temperature variation to realize steam blocking and condensate drainage. Two optional bellows with opening temperature 15℃ or 30℃ below saturation temperature are available.

Structural Features

Excellent air venting capacity, resistant to superheated steam and water hammer.

Cyclic operation with fixed subcooling within full pressure range.

Built‑in bellows in single‑set, double‑set or multi‑set configurations, suitable for large discharge capacity conditions.

High‑corrosion‑resistance temperature‑sensing element for long service life.

Valve body available in carbon steel and stainless steel. Compact and lightweight, performs well in vertical installation and can be mounted at any angle.

Technical Parameters

Main Performance and Component Materials

Model Specification and Overall Dimension