How do Butterfly Valves Works

Butterfly valves have been uniquely designed to perform three functions: start, stop, and control the flow. The butterfly valve’s distinct design has utility and efficiency at its core. The butterfly valve gained popularity in the 1950s, although the first prototype was designed as early as the 18th century. The butterfly valve has found uses in various industrial applications. The oil and petroleum industry once heavily relied on the butterfly value, contributing to its popularity.

The butterfly valve has a simple assembly that can be constructed with handles, manual gears, and pneumatic actuation. The stem and disc configuration turns 90° in the clockwise direction to open and close. The butterfly valve has gained the approval of the masses because of its cost-effective maintenance, lightweight, efficiency, and speed. The basic configuration of any butterfly valve is a stem, disc, seat, and seal.

How does the Butterfly Valve work?

The butterfly valve’s configuration is rather simple compared to the ball, globe, or gate valves. It is advantageous as it occupies smaller space, weighs less, and is easier to install. The butterfly valve consists of a body, disc, seat, and seal. Each of these parts plays a crucial role.

The interiors of the butterfly valve are safeguarded by the body. The seat performs the integral function of sealing together with the disc. It covers the entirety of the inner walls of the valve, and to increase its efficiency, it is either made of metal or elastomeric materials. When the valve closes, the disc sits comfortably on the seat. The disc works with the seat to seal off the flow of the media while the butterfly valve is isolated. The disc has the provision to move partially to make way for a certain amount of the media to flow. The disc is connected to the lever by the stem. The mechanism is put into motion via the stem when the lever is turned.

The mechanism of the butterfly valve requires the lever to be quarter-turned. With this movement, the disc inside turns accordingly depending on the extent to which the lever has been turned. If turned completely, the disc’s position is parallel to the flow, allowing the media to pass at full force. The disc is brought back to its perpendicular position when the valve is closed. It sits on the seat, sealing off the passage completely.

The butterfly valve can be operated manually and alternatively operated pneumatically or electronically. When done pneumatically, the piston that has been employed bears the load of opening the valve by providing the required air pressure. This mechanism has the approval of Chinese manufacturers due to its speed and efficiency. The butterfly valve can be worked electronically with the help of a remotely operated gearbox that turns the stem, which in turn moves the disc when a signal is received.

The Butterfly Valve Seal

The butterfly seals are primarily used as cut-offs and regulating fittings in several applications at high temperatures. The previously mentioned extreme conditions beg the need for absolute internal sealing of the disc. The seal should remain impervious to wear because of the conditions while being flexible. The butterfly seal is an integral part of the butterfly valve that requires careful consideration as it can block three leakage paths – the flanges, the sealing of pipes, and the operating shafts. The design and materials have to be configured according to the application, as there is no room for mistakes with the butterfly valve seal.

Butterfly valve seals play an integral role in the beverage and pharmaceutical industries. The butterfly valve seals made of EPDM are mainly used in the beverage industry as it is known for being capable of withstanding aqueous media, acids, and CIP/SIP processes. The dairy operations work best with FKM, VMQ, and HNBR because of the presence of high-fat content. The pharmaceutical industry is heavily dependent on Fluoroprene XP as the material is resistant to the intense production process.

Harkesh Rubber’s sealing solutions are precisely calibrated with high-quality material and torque-reducing designs. Our butterfly seals have a high pressing action that results in excellent sealing, all while operating with just the required amount of force. Get in touch with our industry experts to learn more.