CONCENTRIC OR RESILIENT-SEATED BUTTERFLY VALVES: A Butterfly Valve is a quarter-turn rotary valves that are used to start, regulate, and stop flow. Butterfly Valve has compact design compare to other type of valves. They require less space and very efficient, light weight, quick operation, and has low-pressure drop and high-pressure recovery. Butterfly valves are use in the following application: air, gases, vacuum, slurry, steam, high-temperature and low-temperature media. There are two types of butterfly valve, a concentric or Resilient-seated Butterfly valves and an ECCENTRIC type. The eccentric type can be single, double, or triple-offset type. There are different kinds of butterfly valves, each adapted for different pressures and different usage.