1. Threaded connection valve. This connection is usually made by turning the valve in and out of the end into a cone or straight pipe thread, which can be connected to the taper pipe threaded joint or the pipe path. Because the connection may have a larger leakage channel, sealing agents, sealing tapes or fillers can be used to plug these channels. If the material of the valve body can be welded, but the coefficient of expansion is very different, or the variation range of operating temperature is larger, the thread connection department must carry on the Honey seal welding.

Threaded valve is mainly the nominal diameter of the valve below 50mm. If the size of the diameter is too large, the installation and sealing of the connecting part is very difficult.

In order to facilitate the installation and removal of threaded connected valves, a fitting is available in the appropriate position of the piping system. Valves with nominal diameter below 50mm can be used as a fitting, and the thread of the pipe sleeve section will connect the two parts together.

2. Flange connection valve. Flange connected valve, its installation and disassembly are more convenient. But the valve is heavier than the threaded connection, and the corresponding price is high. Therefore, it is suitable for all kinds of pipe connection of diameter and pressure. However, when the temperature exceeds 350 degrees, because the bolt, gasket and flange A change of slack, also significantly reduce the load of bolts, the force of a large flange connection may produce leakage.

3. Welded connection valve. This connection is applicable to a variety of pressure and temperature, when used under the conditions of the load, more reliable than the flange connection. However, the welding connection of the valve disassembly and reinstallation are difficult, so its use is limited to the usual long-term reliable operation, or the use of conditional loading, high temperature occasions. such as thermal power plants, nuclear power engineering, Ethylene Engineering pipeline.

Welded valves with nominal diameter below 50mm usually have welded sockets to undertake Hopping-side piping. As the socket welding between the socket and the pipeline to form a gap, it is possible to make the gap by some media corrosion, while the vibration of the pipeline will make the connection site fatigue, so the use of socket welding is limited.

In the larger nominal diameter, the use of conditions, high temperature occasions, the valve body is often used for welding groove, at the same time, the welding seam has the original requirements, must choose a skilled welder to complete this work.