The difference between lug butterfly valve and wafer butterfly valve

I believe that friends who know butterfly valves know that there is a kind of butterfly valve called lug butterfly valve, which looks completely different from our common wafer butterfly valve and flanged butterfly valve. Some people say that lug butterfly valve is wafer butterfly valve, but there are also people disagree with this statement. In this article, Bundor Valve will introduce the difference between the two.
We can look at the picture below, the left is the lug butterfly valve, and the right is the wafer butterfly valve.
From the appearance point of view, the difference between the two is still very large.
There are four holes on the valve body of the wafer butterfly valve, and only need to use long bolts to penetrate the connection hole and flange hole of the wafer butterfly valve during installation. The installation is very convenient, the disadvantage is that the stability is poor.
There are two connection methods for lug butterfly valves:
1. The through-type pressure hole, the installation method is the same as that of the wafer butterfly valve, and the stability is relatively poor compared with the flange connection.
2 The pressure hole of the threaded hole type is different from the wafer type and the flange type. At this time, the pressure hole of the lug type butterfly valve is equivalent to a nut. When connecting with the pipe flange, the bolt passes through the flange. Tighten the pressure hole of the lug butterfly valve directly, and fix the bolt at the flange end with a nut. In this way, the stability is comparable to that of a flanged butterfly valve.