Reasons for using long neck bonnet for the hottest

The reason why low-temperature valves use long neck bonnet is well known. It is applicable to the fact that our team is constantly summarizing the quality temperature in recent years. Shanghai electric valve with a special adhesion strength of -40 ℃ ~ -196 ℃ is called Shanghai Electric low-temperature valve, and this kind of valve generally uses long neck bonnet

Shanghai Dianli low temperature valve adopts long neck bonnet. It is stipulated that low temperature valves include low temperature emergency shut-off valve, low temperature stop valve, low temperature check valve, LNG special low temperature valve, ng special low temperature valve, etc., which are mainly used in 300000 tons of ethylene, liquefied natural gas and other chemical plants. The exported liquid low-temperature media, such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products, etc., are not only flammable and explosive, but also need to be gasified when heating up. When gasifying, the volume expands hundreds of times

Shanghai Dianli cryogenic valve stipulates to use long neck bonnet by 2021 because:

(1) the long neck bonnet has the function of protecting the stuffing box of cryogenic valve, and the plastic recycling channel also needs innovative energy, because the sealing of the stuffing box is one of the keys of cryogenic valve. If the stuffing box leaks, the cold insulation effect will be reduced, resulting in the gasification of liquefied gas. At low temperature, with the decrease of temperature, the elasticity of the packing gradually disappears, and the leak proof performance decreases. Due to the medium leakage, the packing and valve rod freeze, affecting the normal operation of the valve rod. At the same time, the slurry packing will be scratched due to the up and down movement of the valve rod, causing serious leakage. Therefore, it is necessary to ensure that the temperature of the standard part of the filler is above 8 ℃

(2) the long neck bonnet structure is easy to wind cold insulation materials to prevent the loss of cold energy of low-temperature valves

(3) the long neck structure of the low temperature valve facilitates the quick replacement of the main parts of the valve through the removal of the valve cover. Since the process pipes and valves in the cold section of the equipment are often installed in the "cold box", the long neck valve cover can extend through the "cold box" wall. When replacing the main parts of the valve, it is only necessary to disassemble and replace the valve cover without disassembling the valve body. The valve body and the pipeline are welded together to minimize the leakage of the cold box and ensure the tightness of the valve. (end)