Internal structure principle of self-operated pressure reducing valve Low temperature valve test
Self-operated pressure reducing valve is a pressure reducing product that does not need any additional energy and is adjusted by the medium itself. The most important feature of the product is that it can work in places without electricity or gas, and save energy at the same time. The pressure setting value can be adjusted freely in operation.
Self-operated pressure reducing valve is an essential part of the pneumatic control valve, the main role is to reduce the pressure of the air source and stabilize to a fixed value, so that the regulator can obtain a stable air source power for regulating control.
Self-reliant pressure reducing valve is mainly the principle of leverage, using the pressure in the valve control valve opening. When the pressure sensor detects that the valve pressure indicator increases, the opening of the pressure reducing valve decreases; When the pressure decreases after detecting the pressure reducing valve, the opening of the pressure reducing valve increases to meet the control requirements. * Simple as the pressure relief valve on the gas tank at home, you take it apart and everything will be clear. Anyway, you can still use it after you disassemble it.
Self-operated pressure reducing valve adopts fast flow characteristics, sensitive action, good sealing performance, so it is widely used in petroleum, chemical, electric power, metallurgy, food, textile, machinery manufacturing and residential buildings and other industrial equipment in a variety of gas, liquid and steam medium decompression, pressure regulation.
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Low temperature valve test Low temperature valve application:
Low temperature valve refers to low temperature ball valve, low temperature gate valve, low temperature globe valve, low temperature check valve and so on. It is mainly used as fluid control in low temperature storage tank and tank truck, pressure swing adsorption oxygen production device for medium of ethylene, liquefied natural gas, liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide. Low temperature valve refers to the temperature between -40 DEG C -120 DEG C, and -120 DEG C -196 DEG C is called the ** * temperature valve, Taichen low temperature valve after special low temperature treatment, rough machining parts in the cooling medium for a few hours (2-6 hours), to release the stress, ensure the low temperature performance of the material, ensure the finishing size, to prevent the valve in the low temperature condition, Leakage caused by deformation due to temperature change. Valve assembly and ordinary valves are also different, parts need to be strictly cleaned to remove any oil, to ensure performance.
Low temperature valve design:
△ Valve body design: Valve body is the main pressure parts, must have a certain strength to ensure the normal work of the valve. In the low temperature condition, the valve body under the low temperature stress, expansion and contraction of additional stress are very large, to keep the valve seal pair does not deform, the valve body must have a certain stiffness. At the same time, to prevent damage caused by low temperature stress concentration, sharp corners and grooves should be avoided as far as possible in the valve body.
△ long neck valve cover design: low temperature valve needs to use the long neck valve cover structure, its day is to reduce the external incoming heat in the device; Ensure that the temperature of the packing box is above 0℃, so that the packing can work normally; Prevent frosting or freezing of the stem and the upper part of the bonnet at the stuffing box part due to the stuffing box part being overcooled.
△ Pressure relief component design: The problem of abnormal pressure boost generally only exists in the low temperature gate valve. When the gate valve disc is closed, the residual low-temperature medium in the body chamber absorbs heat from the surrounding environment and rapidly vaporizes, generating high pressure in the body. Abnormal BOOST IS VERY HARMFUL, it MAY TIGHTLY PRESS THE GATE against the seat, resulting IN THE GATE stuck, so that the valve can not work properly, may also damage the packing and flange GASkets, and even cause the valve body. Therefore, measures must be taken to avoid it.
Inspection of low temperature valve:
1, low temperature valve in addition to the normal temperature test, must also do low temperature test.
2. Normal temperature test mainly includes shell water pressure strength test, water pressure and air pressure sealing test, upper sealing test, opening and closing and torque test, etc.
2. The main purpose of the low temperature test is to test the operation performance and sealing performance of the low temperature valve in the low temperature state. Operating performance requires flexible valve opening and closing, moving parts and sealing pair shall not be abrade and bite to death. Sealing performance requires valve sealing surface leakage less than the allowable leakage.
In the design process of low temperature valve, various effects of low temperature on the valve should be considered comprehensively, and reasonable structure should be adopted to avoid the adverse effects of low temperature on the normal work of the valve. Shanghai Taichen low temperature valve and general valve working environment is very different, in the process of low temperature valve design, manufacturing, inspection in addition to comply with the valve design, manufacturing, inspection of the general rules, but also should pay special attention to the following points:
All low temperature material components must be cryogenized before finishing.
◇ Adopt reasonable structure, especially to prevent abnormal pressure boost structure and ensure good sealing structure.
Conduct normal temperature test and low temperature test as required.
Select reasonable low temperature materials according to the lower working temperature and working medium.
Post time: Oct-21-2022
