Butterfly valve (also known as flap valve) is a kind of regulating valve with round disc or disc as closing part, which is mainly composed of valve stem, butterfly plate and sealing ring. The valve body is cylindrical with short axial length and built-in butterfly plate. The butterfly plate of butterfly valve is installed in the diameter direction of pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is 0 * ~ 90 ° When it is rotated to 90, the valve is fully open.
The butterfly valve is simple in structure, small in volume and light in weight, and only consists of a few parts. Moreover, the valve can be opened and closed quickly by only rotating 90 *, and the operation is simple. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop through the valve is very small, so it has good flow control characteristics. Butterfly valve has two sealing types: elastic seal and metal seal. Elastic seal valve, seal ring can be embedded in the body or attached to the butterfly plate around.