Check Valves in Steam Trap Systems

Check valves, also referred to as backflow valves, backstop valves, or simply check valves, are integral components used in pipelines or equipment to prevent the reverse flow of media, ensuring fluid flows in one direction only. Operating automatically, they rely on the pressure of the media within the pipeline to open and close. Check valves are categorized as automatic valves and are commonly installed at various points within heating and water supply systems, such as the back end of traps, pump outlets, and after pressure reducing valves, to prevent fluid backflow and mitigate water hammer effects.

Role of Check Valves The primary functions of check valves in piping systems include:

(1). Preventing medium backflow and mitigating water hammer effects.

(2). Safeguarding pumps and their driving motors from reversal.

(3). Preventing medium leakage in containers, such as vacuum equipment, to maintain vacuum integrity. However, it's essential to note that while check valves effectively prevent media backflow when closed, they cannot ensure zero leakage or complete medium cutoff.

Check Valve Types Check valves come in various types, including:

(1). Lift valves: Suitable for horizontal or vertical pipelines, typically used for smaller diameters up to DN100.

(2). Swing or rotary opening valves: Not suitable for installation in vertically downward flow pipelines, commonly used in larger diameter pipelines.

(3). Clamp type valves: Suitable for both horizontal and vertical pipelines, adaptable for various diameters.

Application of Check Valves Check valves find extensive applications in steam systems, particularly concerning the installation of check valves after traps. Some key applications include:

(1). Protecting critical valves from backflow, such as pressure reducing valves and control valves, to prevent operational issues.

(2). Installing check valves at pump outlets to prevent pump damage due to water backflow, which could lead to motor reversal and corrosion issues.

(3). Considerations for installing check valves after steam traps:

• Installation necessity depends on the potential for condensate backflow.
• Check valves are crucial when multiple traps drain into a common recovery line to prevent backflow and water hammer damage.
• In scenarios where condensate piping climbs after the trap, check valves prevent vacuum formation and subsequent backflow.

However, the installation of check valves after steam traps does not guarantee complete prevention of water hammer, as various factors contribute to its occurrence.

Conclusion:

Check valves stand as indispensable components within trapping systems, fulfilling a vital function by staunchly preventing the unwanted reverse flow of media. This critical function ensures the uninterrupted and efficient operation of piping systems and associated equipment. Thus, their presence plays a pivotal role in upholding the integrity and safety standards of the entire system, ensuring optimal performance and mitigating potential risks.