DQ961F Electric Cryogenic Ball Valve Overview

The DQ961F Electric Cryogenic Ball Valve is a specialized ball valve designed for ultra-low temperature media down to -196°C, such as Liquefied Natural Gas (LNG), liquid oxygen, liquid nitrogen, liquid argon, and liquid ethylene. It features an electric actuator for operation and is configured with butt-weld ends for connection.The valve body and key components are manufactured from 304 stainless steel or low-temperature alloy steel forgings. These components undergo deep cryogenic treatment to eliminate residual stresses: rough-machined parts are immersed in liquid nitrogen, cooled to -196°C, held at that temperature for a specified period, and then removed. This cycle is repeated to ensure dimensional stability and mechanical performance of the materials under ultra-low temperatures.The valve incorporates an extended bonnet design, which positions the stuffing box away from the cold zone, preventing the packing from freezing and mitigating valve stem seizure. The ball features pressure relief holes that connect the valve cavity with the pipeline inlet, preventing abnormal pressure buildup caused by medium vaporization.This valve is widely used in LNG terminals, air separation units, cryogenic storage and transportation systems, and low-temperature installations in the petrochemical industry. It is a critical piece of equipment for achieving automated shut-off control under ultra-low temperature working conditions.

DQ961F Electric Cryogenic Ball Valve Product Image

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.