Butterfly Valves – Tougher Than They Sound

A Butterfly valve is shut off vale with a simple construction. They find extensive use in applications such as water supply knows, gas supply and fire protection equipment, etc. This shut off valve in a closed position blocks the valve bore with its disc. When it is in open position, the disc is turned on to allow flow. the valve takes a quarter turn to adapt to a completely open to a completely closed position. Thus, the valve helps in quick opening and closure of the piping systems.

Advantages of using stainless steel butterfly valves

The butterfly valves find extensive usage in a range of applications such as wastewater treatment, water supply systems, gas supply, and fire protection systems, power generation sectors, in oil and chemical industries and in fuel handling systems. The major advantages of these using such valves are that they hold a simple construction and do not take up too much space. They are light weight and also affordable at a lower cost compared with the other valve designs. Also, the valves can be openers by gears, handles, and actuators based on the specific needs of the user.

The main designs of the butterfly valves:

The stainless steel butterfly valves can be either centric or eccentric in its design. The centric or the concentric butterfly valve features a stem, which is centered in the middle of the disc and the disc is again centered in the bore. The eccentric butterfly valves feature is one of more stems which are also known as the stub shafts that are located at the offset from the center. Accordingly, the butterfly valves are categorized as single, double or triple offset valves. The other types of butterfly valve designs are as follows,

Centric butterfly valves with fixed liner:

These are fixed liner butterfly valves that are a very few of their kinds and offer a number of advantages. The rubber is vulcanized directly on the body of the valve forming a permanent bond with the rubber shore hardness. With these valves, there is no deformation or discoloration of the liner. These valves are thus ideal for vacuum conditions as well.

Centric Butterfly valves with loose liner:

The centric butterfly valve with loose liners can be used for a range of applications within water and wastewater treatment plants and also for industrial water applications. This replaceable liner has a robust construction. Its convex form and integrating lip sealing at the shaft passage ensures a tight connection with the shaft. Its special shape ensures a unique grip to the body preventing linear displacements during operation.

Double Centric Butterfly Valves:

The double centric butterfly valves are designed with durability in focus. They feature a tilted and a firmly secured disc, optimized seal design and corrosion protection shaft end zones. The tension of the disc is released after a few degrees of opening, which helps in minimizing the wear of the disc seal.

Reasons why butterfly valves are used widely in industrial applications:

There are specific reasons why the stainless steel butterfly valves find common applications at the industrial and marine markets. Butterfly valves, contrary to their name are extremely reliable and durable even at heavy duty applications. And more than all of this, they demand very little maintenance. Most users have extreme confidence in the performance power of these quarter turn valves.

The term butterfly valve comes from the light and flat design of the product that features a metal disc mounted at the center rod. As they do not weigh as much as other valves, they do not require many supporting structures. Next, to its convenient size and weight, the biggest advantage of these butterfly valves is their flexibility.

Its design enables the user to adjust and regulate the flow of liquids through different disc rotations on a positioning plate. Its actuator, located at the exteriors of the valve and connected with the metal disc can be turned to incrementally regulate the flow of liquids. Such flexibility can allow the butterfly valve to cater to a range of flow control applications.

The working mechanism of Butterfly valves:

When the resilient seat of the valve gets mounted in its body, a seal is formed by the stem that runs through the seat. Additional protection is offered by the packing around the stem. Unlike ball valves, the disc of these butterfly valves is always in contact with the fluid. The main downside is that butterfly valves are less effective when it involves thicker fluids compared with the full bore of a ball valve.

Final words:

Butterfly valves are manufactured with fixed vulcanized rubber liners that further prevent corrosion and keep the valves running smoothly even at high pressure and velocities. These valves have tremendous manual controls, accessories, and actuators to meet the industrial flow control needs.

Ellen Hollington

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