The A49H main safety valve is a high-performance full-opening safety valve that integrates large-displacement relief, cemented carbide sealing, and manual testing functions. The valve is equipped with a manual testing wrench, which supports regular forced opening tests on the valve disc to verify the reliability of its operating mechanism. It adopts a "Y"-shaped cemented carbide seal to ensure long-term tight sealing under high temperature, high pressure, and harsh media conditions. When the system is overpressured, the valve disc quickly opens fully to achieve rapid relief of large flow, and automatically closes after pressure recovery, providing reliable and verifiable overpressure protection for critical industrial systems. It is mainly used in key applications where strict requirements are placed on the sealing performance, discharge capacity, and reliability of safety valves, such as main steam systems of power station boilers, high-temperature and high-pressure reaction equipment in petrochemical industry, large pressure vessels, and industrial steam main pipelines. It is particularly suitable for industrial devices that require regular functional verification to ensure long-term safe standby. It is mainly used as the final pressure relief protection device for large power station boilers (especially supercritical and ultra-supercritical units), main steam systems of industrial boilers, secondary circuits of nuclear power plants, and large high-pressure devices in petrochemical industry. It is usually installed on the boiler superheater outlet header or main steam pipeline, and paired with pulse-type safety valves to form a core safety relief system.

A49H Primary Safety Valve Product Diagram

1. Pilot-operated control, ensuring precise and reliable action

The opening and closing are controlled by an independent pilot valve (pulse valve), and the main valve itself does not have a spring to directly sense pressure. The action is smooth, without chatter, with an extremely small pressure difference during opening and closing, and excellent sealing performance, making it particularly suitable for systems sensitive to pressure fluctuations.

2. Large displacement, suitable for high pressure and large diameter applications

The main valve adopts a full-bore structure, featuring a large discharge area and exceptional discharge capacity. It is specifically designed for large-diameter pipelines above DN100 and high-pressure conditions (such as PN16-PN250), addressing the contradiction between large discharge capacity and structural strength.

3. Alloy steel hard seal (Type "H")

The sealing surface between the main valve disc and the valve seat is made of alloy steel (such as 13Cr) through build-up welding or integrally manufactured, featuring high hardness, wear resistance, and high temperature resistance, ensuring reliable sealing under high temperature and high pressure steam conditions.

4. High sealing performance, with extremely low leakage rate

Under normal operating pressure, the main valve disc is subjected to the combined action of an upward force from the system medium and a downward additional force provided by the pilot system, resulting in a significant sealing pressure ratio, which can achieve a tight seal with near-zero leakage.

5. With a sturdy structure, it maintains relative independence

The main valve body is thick, heavy, and sturdy, capable of withstanding high-pressure impacts. The pilot valve can be independently calibrated, repaired, or replaced without affecting the main valve body, ensuring convenient maintenance.