Introduction to long stem low temperature flange stop valve:
DJ41F-40PDN50 flange cryogenic stop valve uses CF8/304 stainless steel as the shell, PTFE as the valve disc seal and packing seal, and the long rod design has the function of protecting the stuffing box of cryogenic valve, because the tightness of the stuffing box is one of the keys of cryogenic valve. If the stuffing box leaks, the cold insulation effect will be reduced, leading to the gasification of liquefied gas. In the low temperature state, with the decrease of temperature, the elasticity of the packing gradually disappears, and the leak proof performance decreases. Because of the medium leakage, the packing and the valve stem are frozen, which affects the normal operation of the valve stem. At the same time, the slurry packing will be scratched due to the upward and downward movement of the valve stem, causing the valve stem to leak in the switch action.
Cryogenic valves - welded cryogenic long stem stop valve
Use of long rod low temperature flange stop valve:
DJ41F-40PDN50 low temperature stop valve is mainly used for on-off manual low temperature stop valve of storage tank and pipeline at - 40 ℃~- 196 ℃, mainly used for ethylene, liquefied natural gas device, natural gas LPG LNG storage tank, receiving base and satellite station, air separation equipment, petrochemical tail gas separation equipment, low temperature storage tank and tank car for liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide, PSA oxygen generation and other devices. The exported liquid cryogenic media, such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products and other mechanical equipment supporting facilities.
Cryogenic valves - flanged long stem cryogenic stop valve
Structural design of long rod low temperature flange stop valve:
The feature of DJ41F-40PDN50 long rod cryogenic stop valve is that its valve cover is generally of long neck structure, which is shown in the Technical Conditions for Cryogenic Valves (GB/T 24925) It is also clearly stipulated that "the valve covers of cryogenic gate valves, cryogenic globe valves, cryogenic ball valves and cryogenic emergency shut-off valves shall be designed into long neck valve covers that are convenient for cold insulation according to different operating temperature requirements, so as to ensure that the temperature at the bottom of the stuffing box is kept above 0 ℃". The design of lengthening the valve cover structure is mainly to keep the valve operating handle and stuffing box structure away from the low temperature zone, which can not only avoid frostbite caused by too low temperature, but also ensure that the stuffing box and gland can be used at normal temperature, prevent the sealing performance of the packing from decreasing, and extend the service life of the packing.
