ISO 28921 Check Valve

ISO 28921 is a special standard developed by the International Organization for Standardization (ISO) for the design, manufacture and testing requirements of check valves in industrial piping systems. The standard aims to unify the technical specifications of check valves worldwide, covering key links such as material selection, structural design, and performance verification, and is suitable for the anti-backflow control needs in the fields of petroleum, chemical industry, energy, etc.

Structural classification and design features ‌ ‌
Main types ‌:

‌ Swing type ‌: The valve disc rotates around the outer pin shaft of the valve seat, depends on the medium pressure to open, and automatically closes when the reverse flow occurs; ‌

Lift type ‌: The valve disc rises and falls along the vertical axis, suitable for small and medium-sized pipelines, with better sealing performance; ‌

Butt/Axial flow type ‌: Suitable for large-diameter (≥400mm) pipelines to reduce the impact of water hammer effect. ‌
Connection form ‌:

Supports flange end, butt welding end and clamping installation, suitable for different pressure levels (Class 150~2500) and medium characteristics.

 

ISO 28921 Check Valve

 

Applications and Advantages ‌
‌
Typical Applications‌:
Preventing hydrocarbon media backflow in petroleum refining units to avoid the risk of pump reversal;
Blocking backflow in high-temperature steam pipelines to protect boilers and turbine equipment;
Cut-off control of corrosive media (such as strong acids and alkalis) in the chemical industry.
‌
Technical Advantages‌:
Standardized design improves valve interchangeability in the global supply chain;
Diversified structures adapt to complex working conditions, taking into account both sealing reliability and maintenance convenience.

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