Butterfly valves: operation and applications

How one of the most popular industrial valves works and where it is used

Butterfly valves are shut-off valves that allow the fluid flow in a plumbing system to be blocked or regulated. Industrial valves are widely used, especially in two areas, the hydraulic - for example, in pipes or aqueducts - and in the automotive sector (but not only), since it is commonly used in spark ignition engines.

Their main component, as we will see in a moment, is the disc shutter which, by rotating, allows to block the flow of a fluid; keeping it partially open, instead, it is possible to adjust and control its inflow. That’s why they are so crucial within piping and aqueducts for the regulation and management of flows - of water, but not only. Without forgetting the motors, within which they regulate the inflow of mixture.

Let’s see what they are, how they work and what are the main applications of butterfly valves.

What is a butterfly valve and how it works

Butterfly valves are essential elements to ensure the correct flow of fluid into a system. How? They have a metal disc shutter that, rotating on its axis thanks to a shaft placed centrally to the disc itself, compresses the seal covering the valve body. Thanks to a manual control, or through an actuator in the case of motorized valves, it is possible to adjust the degree of opening or closing of the disc in order to completely intercept, or partially, the fluid conveyed.

This type of valve is usually composed of:

• valve body, usually made of spheroidal cast iron, carbon steel or stainless steel;
• a seat, generally an elastomer to ensure the tightness;
• rotating disc, which can be made of spheroidal cast iron, carbon steel, nickel-plated steel or stainless steel;
• shaft, almost always in stainless steel;
• bottom flange, made of the same material as the body.

Valves working at high pressures are often fitted with a small bypass valve. This, when closed, makes it possible to pre-balance the pressures on the two sides of the disc, thus facilitating the opening of the valve. The inner surfaces of the valve which come into contact with the fluid (often water, but not necessarily) must be protected against corrosion.

There is also a particular type of butterfly valve: the wafer valve. This has a particular configuration that features four centering ears obtained by melting the valve body.

What applications do butterfly valves have?

Due to their ability to precisely regulate and control the flow of fluid passing through, and the possibility of closing it completely, butterfly valves are used in a wide range of applications. They are particularly used in the industrial sector, where they are used in installations with dense liquids or suspended particles, not suitable for ball valves.

As we said, there are two main areas of application for this type of valves:

• aqueducts: here they are used as an organ of water interception, often in place of the classic gate valves. In fact, given their small size, the butterfly valves allow you to reduce the space and have a much easier and faster maintenance;
• positive-ignition engines: throttle valves are used regularly in engines (at least the conventional ones and without electronic control). They are located both in the carburettor for air flow regulation and in the injection unit to regulate the flow of the mixture. There is a general difference, however, between diesel and petrol engines:

1. diesel engines: the throttle valve is only used to allow the engine to have a correct shutdown avoiding that sudden movements can generate unintended consequences
2. petrol engines: the throttle valve is used to allow the regulation of the flow of air inside the engine, taking advantage of the construction characteristics of the valve itself.

ECI butterfly valves: efficiency and versatility for a wide range of fluids

ECI butterfly valves are reliable solutions for a wide range of industrial applications due to their efficiency, versatility and ease of use. They are characterised by their robust construction and the use of high-quality materials, such as spheroidal cast iron, to ensure superior performance and long service life, even under intensive use conditions. Thanks to their quick opening and closing mechanism, they minimize energy losses, helping to reduce operating costs.

They are already widely used by various customers in sectors such as the chemical industry, petrochemicals, water treatment, and HVAC systems. They can operate effectively under different conditions of temperature and pressure, and with different fluids such as:

• water (ideal for controlling and regulating the flow of water in water treatment plants, irrigation systems, water distribution networks or cooling installations);
• air;
• oil;
• acid and corrosive fluids.

In the ECI catalogue you will find various types of wafer butterfly valves that comply with the MSS-SP 67 standard, which ensures that they are manufactured according to strict specifications, ensuring reliable and long lasting performance. Their configuration allows quick installation and replacement, reducing downtime and associated costs.

To learn more about the operation and applications of butterfly valves, and to have more information on the valves proposed by ECI, do not hesitate to contact us!