【Execution Standards】

Design Specifications: GB/T1224 API 6D

Connection Dimensions: GB/T 9113 ASME B16.5

Testing and Inspection: GB/T 13927 API 598 API 6D

【Product Applications】

The cryogenic ball valve series is mainly suitable for use in chemical plants such as those producing ethylene and liquefied natural gas, outputting cryogenic liquid media such as ethylene, liquid oxygen, and liquid hydrogen. These media are not only flammable and explosive, but also vaporize upon heating, expanding hundreds of times in volume during vaporization. Furthermore, these media have strong penetrating power, are prone to leakage, and are difficult to manufacture.

【Product Features】

1. The materials of the pressure-bearing components can withstand the expansion and contraction caused by changes in media temperature, and the structure of the sealing parts will not undergo permanent deformation during temperature changes. When used in conditions below -100℃, valve parts should undergo cryogenic treatment before precision machining. This involves immersing the parts in a liquid nitrogen tank for cooling. When the part temperature reaches -196℃, it is kept at this temperature for 1-2 hours. Then, it is removed from the tank and allowed to cool naturally to room temperature. This cycle is repeated twice.

2. The valve cover adopts a long-neck structure to protect the function of the stuffing box, keeping it away from the cryogenic temperature and ensuring the sealing effect of the packing. It can also be wrapped with insulation material to prevent cold energy loss. The neck length (H, see diagram below) of the long neck can be selected according to the operating temperature and the thickness of the insulation material. When the packing seal effect decreases, grease can be added from the middle of the stuffing box (see combined packing structure) to form an oil seal layer, reducing the pressure difference in the stuffing box and improving sealing performance.

3. When the operating temperature is below -100℃, the valve stem material is chrome-plated or nitrided to increase the surface hardness of the valve stem and improve the reliability of the packing seal.

4. The cryogenic ball valve has a structure to prevent abnormal pressure rise. Because the medium in the cryogenic valve vaporizes, its volume expands dramatically, and the pressure will rise abnormally. When the pressure in the valve cavity rises, the valve cavity and the inlet side are connected, or a pressure relief valve is installed at the valve inlet to ensure safe valve operation.

5. The gaskets used in cryogenic ball valves have reliable sealing and recovery properties at room temperature, cryogenic conditions, and under temperature changes.