The correct installation method of butterfly valve and the problems often encountered

The hard-sealed butterfly valve with elastic structure is composed of valve body, valve plate, valve stem, elastic seat, pressure ring and other main parts.

The structure and function of the pressure ring: the side of the pressure ring is the sealing surface of the valve body and the sealing surface of the pipe flange becomes a sealing pair, the side has a bolt hole, and the bolt is used to tighten the pressure ring to fix the seat, and the valve body is connected as one, forming the total structural length of the valve.

Due to the screw aperture on the side of the pressure ring, the effective sealing surface diameter is reduced. From the user's use of flanges, most of them use flat welded flanges, and their internal longitude is also nominal 10~20mm. This use will reduce the effective sealing surface, if the valve and the pipe flange appear different hearts during the installation process, it will be mispositioned on the bolt aperture above, at this time, the pipe flange inside the hole exposed the bolt aperture, resulting in leakage here. The leakage characteristic is that the medium flows out from the back of the pressure ring.

The arrow direction on the valve body refers to the pressure direction of the medium

Usually the arrow direction cast on the valve body refers to the flow direction of the medium, the user sees the arrow, naturally according to the flow direction and the direction of the arrow installation, so the installation has become a habit, the installer is easy to accept this instruction.

However, in terms of butterfly valves with eccentric structure, there are sometimes some problems with such installation, and the following is an example: The eccentric butterfly valve is installed in accordance with the flow direction and the flow direction of the medium, the medium in the tube is liquid, after the valve is closed, if the pressure in the direction of the original medium inlet is reduced or zero, the outlet medium appears backflow backflow, if it is a high level supply, the medium is at a high level and produces pressure, the pressure is greater than the inlet pressure, the valve will bear the effect of reverse pressure, Because the ordinary hard-sealed butterfly valve is a one-way valve, this use is not conducive to the sealing of the butterfly valve, and there will be leaks.

From the above example, it is concluded that the arrow direction of the butterfly valve body refers to the pressure direction of the medium. The user should know the direction of the medium pressure after the valve is closed before installation, and the free valve body arrow direction can be consistent with the direction of the medium pressure to achieve correct use, and the sealing is maintained in good condition.

It is very necessary for users to sample or complete inspection of the purchased valves, and random inspection of the quality of the products is: first, to check the quality of the products, and second, to reduce unnecessary maintenance and updates of the valves after installation, and the success rate of one installation is high. When testing the elastic hard seal butterfly valve, the side of the pressure ring is flat on this plane to place a pressure plate that is basically the same size as the flange and the valve through. If the pressure test machine is used, the pressure claw should be pressed on the pressure plate so that the pressure is evenly distributed on the pressure ring on the side of the valve body.

If it is tested with a blind plate, generally the clamp elastic hard seal butterfly valve is tested with two flanges, flanged elastic hard seal butterfly valve sometimes, the user only uses a flange and the valve bolt below for convenience, at this time, the fixing screw on the pressure ring above the valve body must bear all the pressure of the medium, the previous has said this, These screws cannot withstand the pressure of all the media, so the valve does not leak when tested with a blind plate, and it is basically the same as the actual use.

The above points are often encountered in the installation process, if you understand our valve structure, it will bring you the convenience of installation, and can correctly use the elastic hard seal butterfly valve.