Butterfly valves became a popular choice due to their compact and lighter weight. They operate the same as ball valves with their 90 degree rotation that allows for quick shut off. They come in various types and each has its own unique design features and applications. The most basic design is called a concentric or resilient-seated butterfly valves. This type has a stem in the middle of the disc that is also centered in the pipe bore or port. Typically, it has a rubber (being known for its resiliency) seat and largely relies on the disc that have high level of contact with the seat to cause a seal.
During its 90 degree rotation, the disc will come in contact with the seat at the earliest (about 85+/- degrees). This makes the resilient-seated butterfly valves to be also known as zero offset valve. The major advantage of using this valve is that the flowing media won’t contact the body because the seat is made as a sleeve or cartridge inside the valve’s body. It is commonly used in basic or specialty gas and liquid applications with pressure of up to 200 psi and temperature of up to 400°F. With this, it can handle coatings, chemicals, food, abrasive, and some solid applications. Resilient-seated butterfly valves are made in cast iron or stainless steel which can be epoxy coated. The seat can be made with multiple materials such as natural rubber, teflon, buna, EPDM, and others.
Islip Flow Controls resilient-seated butterfly valves are durable and are designed for universal adaptation of electric or pneumatic handles, gear operators, and actuators. IFC zero offset valves feature a one-piece body for reduced weight but increased strength. The unique stem hole design ensures a dry stem journal and the phenolic backed seat provides more support making the seat non-collapsable. The disc is excellently machined and polished to ensure leak proof positive shut off to minimize operating torque. It is also attached to the shaft using pins to have a solid mechanical connection. IFC butterfly valves are proven to be an excellent choice for commercial and industrial applications.