Suzhou Gold ant Precision Sheet Metal Co.,Ltd , https://www.jmywelding.com
Key words: gate switch seal, influencing factors, torque analysis, valve, as an important part of the control pressure in the fluid transmission process, plays an important role in the entire transmission system, how to maximize its safety, reliability and Stability becomes critical. Valves used in different industries have different industry standards. During inspection of valves and pressure testing, workers need to be inspected and repaired according to industry standards, in addition to valves for production. Words play an important role, so we need to control the valve from the design, production, use, maintenance, testing and other aspects of the valve. Among all the parameters of the valve, the most stable valve stability is its sealing and switching torque.
1. Influencing factors of valve switch sealing and switching torque analysis Valve switch sealing is related to the operation of the valve. If the valve cannot be completely closed due to certain factors, it has a very important influence on the entire transmission system. Through investigation and research, it is found that the valve is closed. The main reasons for the lack of strictness are as follows: (1) Valve sealing structure. According to the theory and field work experience, it can be found that the valve is more effective in the form of post-sealing. The main reason is that when the valve is pressed, the front and rear sections of the valve seal are affected by different degrees of friction, and the seal is sealed by the rear seal structure. It can reduce the friction of the front end and reduce the torque by more than half by theoretical calculation. (2) The size of the connection between the valve stem and the valve plate. There are many different forms of cooperation between the valve stem and the valve plate, and the choice of size is also very different. The valve sealing with the "T" structure can not only make the gap between the valve stem and the valve plate smaller, but also better. Play a role in sealing. In addition, the "T" type structure can make the valve plate less torque and easier during the opening process, so that on the one hand, the deformation between the valve stem and the nut due to the force can be avoided, and on the other hand, the deformation can be reduced. The gap between the nut, the thread and the valve stem ensures maximum sealing stability. (3) The size between the seesaw and the valve body. The size of the cavity between the seesaw and the valve body should be chosen reasonably. Once the size between the two is too large, the valve has a small torque during the opening process, but the clearance is too large to affect the sealing performance. If the gap is too small, it will cause a so-called impact between the two, causing serious damage to the valve. Therefore, the clearance between the stem of the valve stem and the valve stem should be determined to prevent strain between the stem and the shaft during the opening process, which affects the opening torque of the valve. (4) Valve opening structure. The structural connection structure adopted by ordinary valves is a "T" type structure. As can be seen from the above description, the "T" type structure has better sealing performance, but this method is only applicable to valves with relatively low pressure. High-pressure valves should be sealed by an umbrella structure, which not only reduces the switching torque, but also saves labor. However, the umbrella structure has a significant drawback. Because the umbrella structure requires gear meshing, The number of seals required is large, so that the time required to close the valve will be extended accordingly. (5) Valve processing technology. The processing technology that affects the sealing performance of the valve is mainly reflected in the heat treatment process between the valve stem and the nut. When processing the valve, we must ensure the wear resistance of the valve and ensure the hardness. In the aspect of wear resistance treatment, it can be used. Process such as chemical or surface xylan treatment, reducing the friction coefficient between the valve stem and the nut, thereby exerting wear resistance, and the surface strength is improved by hardening treatment, so that not only the switching torque can be reduced, but also The extension of valve life has an irreplaceable important role.
2, the valve is not strict treatment method can be seen from the above description, the factors affecting the valve sealing are mainly reflected in five aspects, for different types of problems should be treated with certain measures to prevent the valve is not tight The serious consequences. (1) When there are impurities in the valve, the valve is full of impurities. A common problem is that the valve will inevitably have many impurities in the process. Therefore, the relevant staff needs to carry out maintenance work on the valve regularly. When the impurity problem affects the sealing, we should not try to close the valve. Instead, we should first open the large valve and then close it properly. Repeat this operation to see if it is effective. If the sealing is still not changed, it needs to be relieved. After that, the gate is cleaned; (2) the stem thread is rusted: when the fluid flows in the valve, it will cause certain corrosion to the valve stem, the valve body and the thread, and when the valve stem and the thread are corroded, it will also appear off. On the one hand, we need daily attention to the maintenance of the valve, on the other hand, we need to check and replace it regularly; (3) Corrosion problems occur in the sealing plate: like the rust of the thread, the flow of corrosive fluid will The valve plate has a certain corrosive effect. For this reason, we need to pay attention to the occurrence of such problems in the daily maintenance process.
3. Conclusion An important factor in judging whether the valve is good or bad when the valve is sealed is as follows. It can be seen from the description that the factors affecting the sealability of the valve and the switching torque are the sealing structure, the connection size of the valve stem and the valve plate, and the jaw plate and In addition to the five basic types of valve body size, valve opening structure, valve processing technology, in addition, the valve sealing is excellent and is also inextricably linked with the design drawings, processing technology and daily use and maintenance, for this purpose, In order to ensure a good sealing of a valve, it is first necessary to start from the most basic part of the design, and secondly to pay attention to the processing of each link. Finally, in the daily use process, it is necessary to strengthen the inspection and maintenance work.
references:
[1] Wang Peng. Research on the Influence of Valve Switch Sealing and Switching Torque[J]. Petrochemical and Chemical Industry Standards and Quality, 2013(2): 49-49.
[2] Yin Yousheng, Wang Dequan. Study on Wear Resistance of Spray Welding Material of Valve Sealing Surface[J]. Journal of Shenyang University of Technology, 1993(4): 39-45.
[3] Yu Shaorong, Wang Jun, Xu Bing, et al. Theoretical analysis and experimental study on the relationship between axial force and tightening torque of manual valve stem [C]// National Conference on Experimental Mechanics. 2009.
Influencing factors and switching torque analysis of valve switch seal
Abstract: Valves are a type of device that we can see everywhere in daily life. The tap water pipe, gas pipeline, oil production wellhead process, etc. are all inseparable from the control of the gate. The degree of sealing of the gate will directly determine whether the fluid can Normal transportation. If the sealing degree of the gate is not enough, the fluid will leak during transportation. The leakage of toxic fluid and polluting fluid will not only cause serious damage to the atmospheric environment, but also have a significant impact on human normal life. The infiltration problem of the valve is usually caused by the lack of tightness. The torque and the position of the force applied to the switch are the most important factors. This paper first introduces the influencing factors of the gate switch seal, and the different influencing factors. Detailed description, followed by a detailed analysis of the switching torque problem, hope that through the research of this article, can further strengthen the pertinence of the staff in the work process, thus ensuring the sealing of the gate.