Butterfly valves are an important part of piping, and they are also quarter-turn valves that can be used to turn on and off or change the flow of something. These valves are easy to install, don’t cost as much, can be used quickly, and have a variety of orifice sizes. The “butterfly” has the impression of a disc and is attached to a rod. The disc rotates when the valve opens, allowing fluid to pass through. When the rod spins, the disc makes a quarter turn to a point perpendicular to the flow direction.

Different Types of Butterfly Valves

There are many different kinds of butterfly valves, each with its use and pressure range. The butterfly valves are classified according to their disc closure design, connection design, and actuation mechanism.

  • Concentric

A centric or concentric butterfly valve is the most basic type. The stem runs across the midline of the disc, and the seat defines the inside diameter peripheral representing the valve body. Since efficient sealing depends on the rubber seat’s flexibility, this zero-offset valve type is also called resilient-seated. When it rotates to 90°, the disc first contacts the seat at 85° and concentric, butterfly valves manufacturer in India are ideal for low-pressure applications.

  • Eccentric

Another type of valve is eccentric, in which the stem does not travel through the disc’s midline but instead stays to the side, indicating the opposite flow direction. The stem of a single offset butterfly valve is precisely behind the disc’s centerline. This design lowers the time the disc contacts the seal before the valve fully closes. Less contact extends the valve’s service life.

The stem of a double offset or doubly eccentric butterfly valve is located behind the midline of the disc, with the added offset on one side. The double eccentricity design of the stem limits disc and seat contact to the last 1-3° of disc closure.

Connection Design

There are separate ways through which butterfly valves connect to the piping system-

  • Wafer- Style

A wafer-style butterfly valve sandwiched between two pipe flanges is a good form. The pipe flanges are connected by long bolts that span the whole valve body. This connection type is appropriate for sealing against bi-directional differential pressures and preventing backflow in universal flow systems. Some models of this valve include flange holes outside the valve body. To achieve efficient sealing, gaskets, O-rings, and flat valve faces on both sides of the valve work together.

  • Lug-style

Lug style, the second type carries threaded inserts (lugs) on the outer side of the valve. Pipe flanges are connected to each side of the bolt inserts by two sets of bolts without nuts. This design allows one side to be disconnected without compromising the other’s function for dead-end service. In general, lug-style butterfly valves that are needed in dead-end applications carry lower pressure ratings. Moreover, unlike wafer butterfly valves, lug-style valves support the piping through the valve body.

Wirings of Butterfly Valve

When you check with Butterfly valves manufacturer in india, there are two wirings:

2-point control actuators: A 2-point control actuator carries three wires: +, -, and the other control wire. When you want to open the complete valve, it is essential to power and un-power to close it, or vice versa. This capability is beneficial if the valve is positioned in a remote location. The valve stays in the most recent position if no power is given to the complete device.

Actuators for three-point control: In 3-point actuators, the four wires are for +, -, and two are for control wires. The valve can be closed or opened depending on which of the two control signals is powered. Three-point control enables intermediate stops. It is important to avoid triggering control wires simultaneously, or the actuator will fail.