DQ961F Electric Cryogenic Ball Valve Features
1. Electric Actuation for Remote Control: Equipped with an electric actuator, the valve supports both on-off and modulating control. It can receive standard control signals such as 4-20mA, enabling remote automatic operation. The actuator features built-in thermal overload protection and includes a manual override mechanism for emergency operation during power outages.
2. Cryogenic Treatment and Low-Temperature Materials: Components undergo deep cryogenic treatment prior to final machining. Parts are immersed in a liquid nitrogen chamber, cooled to -196°C, held at that temperature for 1-2 hours, and then allowed to return naturally to room temperature. This cycle is repeated twice to relieve residual stresses, ensuring dimensional stability and mechanical performance at -196°C.
3. Extended Bonnet Anti-Freezing Design: The bonnet features a long-neck structure, positioning the stuffing box away from the low-temperature zone to ensure effective packing sealing. It also allows for the wrapping of insulating materials to prevent cold energy loss. The neck length is selected based on the operating temperature and the thickness of the insulation material.
4. Abnormal Pressure Rise Prevention Structure: Cryogenic media expand dramatically in volume upon vaporization, causing abnormal pressure increases. The valve incorporates pressure relief holes in the ball that connect the valve cavity with the pipeline inlet port. When pressure builds up in the cavity, the medium is relieved to the inlet pipeline, ensuring safe valve operation.
5. Hardened Stem Surface Treatment: For service temperatures below -100°C, the stem material undergoes chromium plating or nitriding treatment. This increases the surface hardness of the stem and enhances the reliability of the packing seal.