Clip-on butterfly valves and flange butterfly valves are two kinds of common butterfly valves. The application range of the two butterfly valves is very wide, but many friends can't tell the difference between the clip-on butterfly valve and the flange butterfly valve, and they don't know much about the difference between the two. 

 The clamp and flange of the butterfly valve are two connection methods. In terms of price, the clip type is relatively cheaper, and the price is roughly 2/3 of the flange. If you want to choose an imported valve, use the clamp type as much as possible, which is cheap and light in weight. 

 The length of the clamp valve bolt is long, and the construction accuracy is high. If the flanges on both sides are not right, the bolts will suffer greater shear force, and the valve is easy to leak. 

 The clamped valve bolts are generally long. Under high-temperature conditions, the expansion of the bolts may lead to leakage, so it is not suitable for large pipe diameters under high-temperature conditions. Moreover, the clip-on butterfly valve generally cannot be used at the end of the pipeline and the downstream where it needs to be removed, because when the downstream flange is removed, the clamp valve will fall off. In this case, it is necessary to make another short joint to disassemble, and the flange butterfly valve does not have the above problem, but the cost will be relatively high. 

 There are no flanges at both ends of the clamped butterfly valve body, only a few guide bolt holes. The valve is connected with a set of bolts/nuts to the flanges at both ends. In contrast, it is more convenient to disassemble, and the cost of the valve is low, but the disadvantage is that there is a problem with one sealing surface, and both sealing surfaces have to be disassembled. 

 There are flanges at both ends of the flange butterfly valve body, which is connected to the pipe flange. The seal is relatively more reliable, but the cost of the valve is relatively high.