Author: Site Editor Publish Time: 2018-11-23 Origin: Site
The double offset butterfly valve is further improved on the basis of a single eccentric butterfly valve. The structural feature is that the stem axis is offset from the center of the disc and from the center of the body.
The double offset butterfly valves are mainly used for system drainage of water plants, power plants, steel mill smelting, chemical, water source projects, environmental facilities construction, etc. It is especially suitable for use on water pipelines as a regulating and intercepting device.
The double offset effect allows the disc to be quickly disengaged from the valve seat after the valve is opened, which greatly eliminates unnecessary over-squeezing and scraping of the disc and the valve seat, reduces the opening resistance, reduces wear and improves the seat life. The scraping is greatly reduced, and the double offset butterfly valve can also be used with a metal valve seat, which improves the application of the butterfly valve in the high temperature field.
The double offset butterfly valve is characterized by being eccentric from both the center of the disc and the center of the body at the axis of the valve stem. The double offset effect allows the disc to be quickly disengaged from the valve seat after the valve is opened, which greatly eliminates unnecessary over-squeezing and scraping of the disc and the valve seat, reduces the opening resistance, reduces wear and improves the seat life.
The double offset butterfly valve is a valve that uses a circular disc as a starting and closing member and rotates with the valve stem to open, close and adjust the fluid passage. The butterfly valve's disc is mounted in the diameter direction of the pipe. In the cylindrical passage of the butterfly valve body, the disc-shaped disc rotates around the axis, and the rotation angle is between 0° and 90°. When the rotation is 90°, the valve is fully open.
The butterfly valve, also known as the flap valve, is a simple regulating valve and can also be used for switching control of low pressure pipeline media. A butterfly valve is a valve in which a closing part(valve or disc) is a disc that rotates around the valve shaft to open and close, and is mainly used for cutting and throttling on the pipeline. The butterfly valve opening and closing member is a disc-shaped butterfly plate that rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjusting.
The butterfly valve is normally less than 90° from full opening to full closing. The butterfly valve and the butterfly rod have no self-locking capability. For the positioning of the butterfly plate, a worm gear reducer is added to the valve stem. The use of a worm gear reducer not only enables the disc to have a self-locking capability, but also stops the disc at any position and improves the valve's operating performance. The characteristics of the industrial special butterfly valve can withstand high temperature, the applicable pressure range is also high, the valve has a large nominal diameter, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of the rubber ring. Large high temperature butterfly valves are manufactured by steel plate welding and are mainly used for flue ducts and gas pipes of high temperature media.