Electric insulated butterfly valves, also known as electric jacketed butterfly valves, are based on standard triple-offset metal hard-seal butterfly valves with an external metal jacket welded onto the valve body. Jacketed interfaces are installed on both sides of the valve body, allowing steam or other superheated gases to be introduced to prevent the medium from solidifying or crystallizing at ambient temperatures. The flanges of insulated butterfly valves are one to two sizes larger than those of standard metal hard-seal butterfly valves. Electric insulated butterfly valves are primarily used in petroleum, chemical, metallurgical, pharmaceutical, and other industrial systems.