Butterfly valves and flanged butterfly valves are two common types of butterfly valves. The scope of application of the two butterfly valves is very wide, but many friends can not distinguish between the clamp butterfly valve and the flange butterfly valve, do not know the difference between the two.
The clamp and flange of the butterfly valve are two types of connection. In terms of price, the sandwich type is relatively cheap, and the price is roughly 2/3 of the flange. If you want to choose imported valves, as far as possible to use clamping, cheap, light weight.
Clamping valve bolt length is longer, the construction accuracy requirements are higher, if the two sides of the flange is not in the center, the bolt will be subjected to large shear force, the valve is easy to leak.
Clamping valve bolts are generally long, and 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. And the splint butterfly valve generally can not be used for the end of the pipeline and the downstream need to be disassembled, because when the downstream flange is removed, the splint valve will fall down, in this case, it must be done in another sub in order to disassemble, and the flanged butterfly valve does not have the above problem, but the cost will be relatively high.
There are no flanges at both ends of the butterfly valve body, only a few guide bolt holes, and the valve is connected with a set of bolts/nuts and flanges at both ends. In contrast, the disassembly is more convenient, the valve cost is lower, but the disadvantage is that a sealing surface problem, two sealing surfaces have to be disassembled.
The flanged butterfly valve body has flanges at both ends, which are connected with the pipe flange, and the sealing is relatively more reliable, but the valve cost is relatively high.