Butterfly valves have been around for a long time and are used in a variety of applications. They made their debut in the 1930's and have been used in several industries ever since. There are several different types of butterfly valves, but they fall into two basic types - lug valves and wafer valves.

A butterfly valve is recognized as a "quarter-turn" valve. The valve is designed to open or close when the metal disc rotates a quarter turn. The disc is connected with the stem. When the butterfly valve is fully open, the disc rotates (1/4 turn), allowing almost unimpeded flow of fluid.

Lug butterfly valve

The lug butterfly valve’ design is similar to a three-piece ball valve, as one end of the line in it can be removed without affecting the other side. This can be performed by threaded inserts, flanges, and two sets of lugs (bolts) that do not use nuts, as each flange has own bolts. It's also salient to note that you can clean, inspect, repair or replace the lug butterfly valve i line without interfering the whole system, but, by the way, you'll need to do it when it comes to Wafer valves.

Wafer butterfly valve

A wafer butterfly valve is utilized to secure a seal to defend dual-directional pressure differential in the flow. This is achieved by the use of tight fit seals such as precision machined O-rings, washers, and flat valve surfaces on the downstream and upstream parts of the valve.

After all, lug and wafer butterfly valves both are now used in lots of applications for industrial sectors that include food processing, pharmaceutical, chemical, oil, water as well as sewage management.