Butterfly Valves

Butterfly valves belong to a family of valves known as quarter-turn valves. A disk is housed in a pancake, wafer, or lug style housing that when actuated a quarter turn will shut off flow. Due to this design they make perfect candidates for on/off service and are also often used as an inexpensive means of flow control. The seals and seats are made of many different materials depending on product applications.

Housings can be made from anything from cast iron to stainless steel. Three of the most common styles are resilient seated, high performance, and triple offset. Resilient butterfly valves using rubber seats and having the lowest pressure ratings. High performance butterfly valves are used in higher-pressure systems and triple offset butterfly valves make use of metal seats enabling them to be used for high-pressure systems. Similar in nature to a ball valve they are quick shutting but because of the ever present centered disk will cause a slight pressure drop.

There are many butterfly valve manufacturers. ATSCO Sales & Service is proud to represent/distribute Crane Valves including: Centerline Resilient Seated Butterfly Valves and Flowseal High Performance Butterfly Valves. ATSCO also distributes Maxseal Butterfly Valves including: Resilient Seated and High Performance Valves (Sold by ATSCO - full category in online store).

Other manufacturers of butterfly valves are FNW, Watts, Nibco, Pratt, Bray, Valtorc, and Keystone.

Butterfly valves are a circular housing in which a stem supports and controls a disk that is moved in a rotary motion to regulate or shut off flow of a piping system.

Concentric butterfly valves use a metal dist wit a resilient rubber seat to control flow or shut off low pressure systems.

Double offset butterfly valves also called double eccentric butterfly valves have a slight offset in the disc positioning which enables the valve to have better seating ability. This makes for improved valve wear and increased ability to hold pressure. High performance valves use different materials for the disk and seat depending on what product will be used with them.

Triple offset valves or triple eccentric butterfly valves have either laminated or solid metal seats. The benefit of this design is that the only time the seat and the disk come in contact is at complete closure. This makes for better wear and less chance of scratching. This design is also ideal for high pressure situations.

There are several styles of controls that actuate butterfly valves. Manually operated valves are usually done so through a lever or gear box. Lever styles being common on valves that need to be locked down in a semi permanent flow control setting.

Pneumatic spring return actuators and pneumatic double acting actuators are commonly used in on off applications. Pneumatic spring return actuators use air to move the valve and a spring to return to preset position while a pneumatic double acting actuator uses air for moving the valve both directions. Electric actuators use sensors and electricity to actuate valves. This set up is common in systems that need varying degrees of flow control and shut off ability. Several brands of actuators and actuator interfaces ATSCO Sales & Service carry are Auma, Hytork, Indelac, Vac, Profibus, and Fieldbus Valve Positioners.

There are a vast number of uses for butterfly valves throughout many industries.

• • Mining
• • Power Generation
• • Chemical Manufacturing
• • Water / Waste Water
• • Irrigation
• • Food
• • Dairy
• • Heating and Cooling Systems
• • Paper and Pulp

The list goes on and on and new uses for these versatile valves come into being every day.

Butterfly valves are used in piping systems where on off service is needed. Also used for modulating applications and flow control. These valves can be set up to be used in liquid and gas applications depending on the need. Another bonus is its not practical to use a ball valve in piping over 6” and butterfly valves have just about no limit on the size they can be run in. Its not uncommon for industrial applications to run 24” to 40” butterfly valves.

The industry is seeing use of butterfly valves over ball valves, plug valves, pinch valves, and glove valves in a lot of areas. The lighter weight and mounting design of butterfly valves make them easier to support and hang compared to many other style of valves. Another bonus in flow control and modulating systems is the internal disk design of the valve makes for less vibration and sound over other styles of valves used for this application.

Cost is another reason to look into butterfly valves. Due to design and construction butterfly valves can cost considerably less to purchase.