Butterfly valve refers to a kind of valve whose closing part (disc or butterfly plate) is a disc, which rotates around the valve shaft to achieve opening and closing. It is mainly used for cutting off and throttling on the pipeline.
The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjustment. The butterfly valve is usually less than 90″ from fully open to fully closed,
The butterfly valve and butterfly stem have no self-locking ability. For the positioning of the butterfly plate, a worm gear reducer should be installed on the valve stem. The use of a worm gear reducer can not only make the butterfly plate self-locking and stop the butterfly plate at any position, but also improve the operating performance of the valve.
The industrial butterfly valve is characterized by high temperature resistance, high applicable pressure range, large nominal diameter, and the valve body is made of carbon steel.
The sealing ring of the valve plate uses a metal ring instead of a rubber ring. The large high temperature butterfly valve is made of steel plate welding, and is mainly used for flue ducts and gas pipes of high temperature media.
The installation and maintenance of the butterfly valve should pay attention to the following items: During installation, the valve disc must be stopped in the closed position. The opening position should be determined according to the rotation angle of the butterfly plate.
For butterfly valves with a bypass valve, the bypass valve should be opened before opening
The installation should be carried out according to the installation instructions of the manufacturer, and the heavy butterfly valve should be installed with a firm foundation.
The advantages of butterfly valves are as follows: convenient and rapid opening and closing, labor-saving, low fluid resistance, and can be operated frequently.
Simple structure, small size and light weight.
Mud can be transported, with the least accumulation of liquid at the pipe mouth.
Under low pressure, good sealing can be achieved.
Good adjustment performance.
The disadvantages of butterfly valves are as follows: the range of operating pressure and operating temperature is small.
The tightness is poor.
Butterfly valves can be divided into offset plate type, vertical plate type, inclined plate type and lever type according to the structure. According to the sealing form, it can be divided into two types: relatively sealed type and hard sealed type. The soft seal type generally uses a rubber ring seal, and the hard seal type usually uses a metal ring seal.
According to the connection type, it can be divided into flange connection and wafer connection; according to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.