The butterfly valve is a valve that uses a disc-type opening and closing member to reciprocate about 90° to open, close and adjust the fluid channel. The butterfly valve is not only simple in structure, small in size, light in weight, low in material consumption, and small in installation size, but also has a small driving torque, is easy and quick to operate, and can also have good flow regulation function and closing and sealing characteristics at the same time. It is one of the fastest-growing valve varieties in the past decade. Especially in industrially developed countries such as the United States, Japan, Germany, France, and Italy, butterfly valves are widely used, and their varieties and quantities are still expanding, and they are developing in the direction of high temperature, high pressure, large diameter, high sealing, long life, excellent adjustment characteristics and one valve with multiple functions. Its reliability and other performance indicators have reached a high level, and it has partially replaced stop valves, gate valves and ball valves. With the advancement of butterfly valve technology, in the foreseeable short term, especially in the field of medium and low pressure use of large and medium-sized ports, butterfly valves will become the dominant valve form.
