What are butterfly valves?
There's a common misconception that butterfly valves can't be utilized to regulate fluid flow properly. However, we do not recommend doing so since it may damage the valve disc and reduce its sealing properties. They are used in many different process media and industries, most notably in water supply, collecting, distribution, and pumping stations, because of their versatility and ability to isolate flows. Their compact size and relatively simple design are two of the main advantages that set them apart from other families of valves. Because of this, the final products may outperform those of rival valve families in terms of cost, weight, size, and speed of actuation.
Several criteria allow for the categorization of this valve type:
Body and disc-centric, double eccentric, and triple eccentric designs employ materials such as cast iron and high nickel alloys. Wafer, lug (semi or full), flanged, and double-flanged end connections are all possible; seats may be soft (Teflon, Buna, rubber, etc.) or metal-to-metal (Stainless Steel 304, Stainless Steel 316). Mechanical (lever, gear, worm gear) and manual (actuated) (electric, pneumatic, hydraulic, and gas-over-oil types). The water and wastewater treatment sectors, as well as the chemical and oil industries, the transportation sector, the energy sector, and the fuel and oil handling equipment all benefit from the usage of butterfly valves. Previously dominated by globe and ball valves, the oil and gas sectors have recently seen an uptick in the use of butterfly valves, particularly those with double and triple eccentric designs.
How do butterfly valves do works?
The major part of a butterfly valve is the disc, which is a metal ring located in the middle of the pipe and connected to an external actuator (manual level or actuator) through a rod. The pressure loss caused by a butterfly valve is greater than that caused by a ball valve because the disc of a butterfly valve is in constant touch with the substances transported by the pipe. When the disc is in its closed position, the valve's bore is sealed off; in its open position, fluid may flow freely through. As little as a quarter of a turn is all that's needed to switch the valve from its fully open to fully closed position (and such movement can be executed as quickly as for ball valves).
Types of butterfly valves:
Following are the types of butterfly valves;
The centric or concentric butterfly valve is the most fundamental form that a butterfly valve may have. The seat is located on the inner diameter perimeter of the valve body, and the stem is positioned so that it passes through the midline of the disc. Because good sealing depends on the rubber seat's elasticity, this zero-offset valve type is also known as resilient-seated. During the closing process, the disc makes its first contact with the seat at an angle of around 85 degrees out of a total of 90 degrees. Low-pressure applications are appropriate for the use of concentric butterfly valves.
An eccentric butterfly valve does not run down the disc's midline as a conventional butterfly valve does. Instead, it moves in the opposite direction of the flow, behind the disc, which is the same direction as the flow (right). The stem of a single offset butterfly valve is always placed in such a way that it is exactly behind the disc's midline. Because of the manner that this component is constructed, there is less contact between the disc and the seal before the valve is entirely shut before it is totally closed. When there is less contact between the moving portions of the valve, the valve tends to have a longer life.
The stem of a double offset butterfly valve, also referred to as a doubly eccentric butterfly valve, is positioned beyond the midline of the disc, and there is an additional offset to one side of the disc. Because the stem is designed with a twofold eccentricity, the disc and seat do not come into touch with one another until the very final 1-3 degrees of disc closure.
Due to the fact that the design of a triple offset butterfly valve, which is also known as a TOV or TOBV, is analogous to that of a double offset butterfly valve, it is suitable for use in applications that are considered to be mission-critical. The third kind of offset is represented by the axis of contact between the disc and the seat. There is very little contact that takes place prior to the valve being completely closed as a result of the conical shape of the seat surface and the same shape that can be observed at the ridge of the disc. This allows for the valve to function more efficiently. A triple-offset butterfly valve is more durable than a conventional butterfly valve and needs much less maintenance than a standard butterfly valve. Triple offset valves often feature metal seats to eliminate the possibility of air bubbles forming during the shut-off process. Because of their metal seating, butterfly valves are able to endure greater temperature variations than other types of valves.
Utilizing the pressure that is already there in the pipeline allows high-performance butterfly valves to achieve a better seal between the seat and the disc edge. This is accomplished by applying pressure to the seat. These butterfly valves have pressure ratings that are far higher than the industry standard and are significantly less prone to wear out.
Butterfly valves find usage in a wide variety of sectors and applications, including the food industry, the pharmaceutical, chemical, and oil industries, as well as fire protection, water supply, wastewater treatment, gas supply, fuel handling, and sanitary fittings. It is common to practice installing water control butterfly valves in pipes so that they may perform the function of control valves and stop the flow of water. The control of slurries and liquids that contain relatively high concentrations of solids while running under low pressures is an ideal application for these valves, which are offered in a broad range of sizes and may be purchased in a variety of configurations. Stainless steel butterfly valves are often used in conditions that are prone to corrosion, such as marine environments. This is mostly attributable to the material's high level of durability as well as its resistance to corrosion.
Ball Valves VS Butterfly Valves:
A butterfly valve that has features that are equivalent to those of a ball valve would often have lower costs, be easier to install, and need a smaller installation footprint than a ball valve would. On the other hand, it is not feasible to remove the discs from butterfly valves in order to clean them since the valves include the discs already. Ball valves are advantageous for high-pressure applications with small diameters because they are better suited for larger pressure variations and provide little pressure drop across the valve. This makes ball valves a good choice for applications with these characteristics. Because of this, ball valves are an excellent option for applications that have these specific qualities. The design of butterfly valves is very simple since there are fewer moving parts and fewer pockets or traps for the medium that they are controlling in its construction. As a consequence of this, they are easier to repair and need less general maintenance as a whole. When working with pipes of smaller size, a ball valve is often the best option available, both in terms of the torque it requires and the expense it entails. Butterfly valves begin to show their advantages in terms of torque and cost somewhere at DN 50 and higher. For additional information on the differences and parallels that exist between the two types of valves, please refer to the article that we have written that contrasts butterfly valves with ball valves.
What GMK offers?
GMK is the top-rated seller of butterfly valves and the variants that are sold the most are; Concentric Resilient Seated Butterfly Valve, Cryogenic Triple Offset Butterfly Valve, GMK Double Eccentric Butterfly Valve, GMK Full Lined Butterfly Valve.
Butterfly valves come in a wide variety of sizes, shapes, and configurations, and each has its own unique installation and fittings. Carburetors are the most common location for these valves in automotive systems. The airflow to the car's engine may be adjusted using the valve. To control the flow of air, it is designed to open just partly. You may reach out to GMK for any queries you may have concerning the valves needed for your industrial facilities or company, and we will gladly provide you with the information you want.