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2019

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Classification and description of back pressure valve connection methods

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Classification and description of valve connection methods of back pressure valve: Nowadays, the application range of valves is getting wider and wider, and corresponding valves should be used in different environments. The entire valve has different connections with pipelines or equipment. Regardless of whether it is installation or use and maintenance, attention must be paid to it. Improper valve connection methods may easily cause the valve to run, pop, drip, leak, etc. Therefore, valve users should treat it according to the actual situation.

 

Classification and description of valve connection methods of back pressure valve:

Nowadays, the application range of valves is getting wider and wider, and corresponding valves should be used in different environments. The entire valve has different connections with pipelines or equipment. Regardless of whether it is installation or use and maintenance, attention must be paid to it. Improper valve connection methods may easily cause the valve to run, pop, drip, leak, etc. Therefore, valve users should treat it according to the actual situation.

 

There are many types of valve connections. Common valve connection methods include: flange connection, clamp connection, butt welding connection, threaded connection, ferrule connection, clamp connection, self-sealing connection and other connection forms. This article will focus on explaining the most common problems that occur during the installation process of flange connections, butt weld connections and threaded connections. I hope it will be helpful to everyone.

 

 

Threaded back pressure valve

A simple connection method often used on small valves. This connection is usually made by processing the inlet and outlet ends of the valve into tapered pipe or straight pipe threads, which can be connected to tapered pipe thread joints or pipelines. Because this type of connection can have large leak channels, these channels can be plugged with sealant, sealing tape, or filler. If the material of the valve body can be welded, but the expansion coefficient is very different, or the operating temperature changes within a large range, the threaded connection must be sealed and welded. Threaded valves are mainly valves with a nominal diameter of less than 50 mm . If the diameter is too large, it will be difficult to install and seal the connection. In order to facilitate the installation and disassembly of threaded valves, pipe joints are available at appropriate locations in the piping system. Valves with a nominal diameter of less than 50mm can use pipe sleeves as pipe joints, and the threads of the pipe sleeves connect the two parts together. Such as internal thread back pressure valve

 

Flange back pressure valve

Flange-connected valves are the most commonly used connection form among valves. Its installation and disassembly are relatively convenient. However, it is bulkier than threaded valves, and the corresponding price is also higher. Therefore, it is suitable for pipe connections of various diameters and pressures. However, when the temperature exceeds 350 degrees, as the bolts, gaskets and flanges become loose, the load of the bolts is also significantly reduced, and leakage may occur in flange connections that are subject to great stress. Flange connection type back pressure valve

 

 

Welded back pressure valve

This type of connection is suitable for various pressures and temperatures and is more reliable than flange connections when used under heavier conditions. However, it is difficult to disassemble and reinstall welded valves, so its use is limited to situations where it can usually operate reliably for a long time, or where the operating conditions are severe and the temperature is high. Such as on the pipelines of thermal power plants, nuclear energy projects, and ethylene projects. Welded valves with a nominal diameter of less than 50mm usually have a welding socket to accept the pipe at the load plane end. Since socket welding forms a gap between the socket and the pipe, the gap may be corroded by certain media. At the same time, the vibration of the pipe will fatigue the connection part, so the use of socket welding is subject to certain restrictions. In situations where the nominal diameter is large, the operating conditions are severe, and the temperature is high, the valve body is often grooved butt welded. At the same time, there are original requirements for the welding seam, and welders with excellent skills must be selected to complete this work. Such as welded back pressure valve.