DQ367H Top-Entry Cryogenic High-Pressure Ball Valve Overview

The DQ367H Top-Entry Cryogenic High-Pressure Ball Valve is a high-performance ball valve designed with a top-entry structure, specifically developed for cryogenic and high-pressure operating conditions. It is suitable for media at -196°C, such as Liquefied Natural Gas (LNG), liquid oxygen, liquid nitrogen, liquid helium, and liquid ethylene.The valve features a one-piece body construction with a top bonnet connection. This design allows for online maintenance, enabling the removal of internal core components such as the stem, ball, and seats from the top without dismantling the valve from the pipeline. The pressure-containing parts are manufactured from high-strength cryogenic alloy steel or forged stainless steel. Prior to final machining, all components undergo a deep cryogenic treatment process: parts are immersed in a liquid nitrogen chamber, cooled to -192°C, held at that temperature, and then removed. This cycle is repeated twice to relieve residual stresses, ensuring material stability and performance under cryogenic temperatures.This valve is widely used in critical systems requiring high reliability and ease of online maintenance, including LNG terminals, air separation units, and cryogenic high-pressure pipelines.

DQ367H Top-Entry Cryogenic High-Pressure Ball Valve Product Image

DQ367H Top-Entry Cryogenic High-Pressure Ball Valve Features

1.  Top-Entry Online Maintenance Structure: The unique top-entry design allows for the removal of the bonnet and the lifting out of core components such as the ball, stem, and seats for inspection, cleaning, or replacement without cutting the valve out of the pipeline. This significantly reduces maintenance downtime.

2.  Cryogenic Treatment and High-Pressure Cryogenic Materials: The pressure-containing parts are manufactured from materials capable of withstanding expansion and contraction caused by temperature changes. Prior to final machining, all components undergo a deep cryogenic treatment process: parts are immersed in a liquid nitrogen chamber, cooled to -192°C, held at that temperature for 1-2 hours, and then allowed to return naturally to room temperature. This cycle is repeated twice to ensure dimensional stability and mechanical performance at -196°C.

3.  Extended Bonnet Anti-Freezing Design: The long-neck bonnet structure is designed to protect the function of the stuffing box. It positions the stuffing box far away from the low-temperature zone, ensuring the sealing effectiveness of the packing. Additionally, it allows for the wrapping of insulating materials to prevent the loss of cold energy.

4.  Abnormal Pressure Rise Prevention Safety Structure: The valve is equipped with a structure to prevent abnormal pressure rise. Since the medium inside a cryogenic valve expands dramatically in volume upon vaporization, the pressure can increase abnormally. When pressure builds up in the valve cavity, this design connects the cavity with the inlet port or incorporates a pressure relief valve at the valve inlet, ensuring safe 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.

6.  Adjustable Seal and Lubrication Injection Maintenance: The valve seat features an adjustable seal design. When the sealing effectiveness of the packing decreases, lubricating grease can be injected through the packing chamber to form an oil seal layer. This reduces the pressure differential across the packing and improves sealing performance.