The characteristics and precautions of butterfly valves and the advantages and disadvantages of butterfly valves

Butterfly valve (butterflyvalve) 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 the 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. Industrial-specific butterfly valves are characterized by high temperature resistance and higher applicable pressure range. The valve has a large nominal diameter. The valve body is made of carbon steel. The sealing ring of the valve plate uses a metal ring instead of a rubber ring. Large high-temperature butterfly valves are manufactured by welding steel plates, and are mainly used for flue ducts and gas pipes for high-temperature media.

The installation and maintenance of the butterfly valve should pay attention to the following matters: During installation, the disc should 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 bypass valves, 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-weight butterfly valve should be installed with a firm foundation.

The advantages of the butterfly valve are as follows: It is convenient and quick to open and close, labor-saving, low fluid resistance, and can be operated frequently. Simple structure, small size and light weight. Mud can be transported, and the accumulation of liquid at the pipe mouth is small. Under low pressure, good sealing can be achieved. Good adjustment performance.

The disadvantages of butterfly valves are as follows: The operating pressure and working temperature range are 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 generally 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.