In modern industrial and commercial projects, valve selection directly affects system efficiency and maintenance costs. Butterfly valves, with their simple design, reliable sealing, and lightweight construction, have become one of the most common flow control devices in HVAC systems as well as in municipal water supply, wastewater treatment, and cooling water circuits. But what makes butterfly valves stand out in these applications?

1. Compact Structure and Small Installation Space

Compared with other types of valves such as ball valves and gate valves, butterfly valves have a simpler design. They mainly consist of a body, disc, stem, and sealing ring. The disc functions both as a shut-off element and a flow control component, making the overall valve smaller and lighter—ideal for areas with limited space or tightly arranged piping.

In HVAC systems, equipment rooms, chilled water pipelines, and fan coil connections often have restricted space. Using butterfly valves can effectively save installation space and reduce the load on supports.

2. Easy Operation and Quick On/Off

Butterfly valves typically achieve full open or full close with just a 90° rotation of the disc. Whether operated manually, pneumatically, or electrically, the valve responds quickly and smoothly. This makes them ideal for applications that require frequent flow adjustments or rapid system shut-off.

For example, in cooling tower water circulation, butterfly valves can quickly adjust flow to respond to load changes, ensuring stable system operation.

3. Excellent Flow Control Performance

In low to medium pressure piping systems, butterfly valves offer effective flow regulation. Their disc design creates relatively low resistance and minimal pressure drop, allowing stable flow control across a wide range of openings.

In water treatment systems, butterfly valves are used on raw water, treated water, and wastewater lines to precisely control fluid flow, helping optimize the overall process.

4. Wide Applicability and Cost-Effectiveness

Modern butterfly valves are available in a variety of materials, including cast iron, carbon steel, stainless steel, and special alloys. Sealing materials can also be selected according to the medium, such as EPDM, NBR, or PTFE.

This versatility allows butterfly valves to perform well not only with clean water and chilled water but also in corrosive media like seawater and chemical solutions.

Compared to other valve types, butterfly valves have lower manufacturing and installation costs for the same nominal diameter, making them especially economical for large-diameter applications. For instance, in municipal water main pipelines, butterfly valves with DN600 and above are often standard.

5. Easy Maintenance and Long Service Life

Butterfly valves have a simple structure and are easy to maintain. Most designs use replaceable rubber or elastomeric seals, so routine maintenance generally involves checking seal wear and lubricating the stem.

Moreover, the advent of modern triple-offset metal-seated butterfly valves has enhanced reliability and durability, even under high-temperature, high-pressure, or steam service conditions.

Q&A

Q1: Can butterfly valves be used for flow regulation?

Yes. Butterfly valves can not only perform on/off control but also provide stable flow regulation within a certain opening range, making them particularly suitable for throttling in low- to medium-pressure systems.

Q2: Why are butterfly valves not suitable for high-pressure systems?

Due to their structural characteristics, butterfly valves have relatively weaker sealing performance under high-pressure or high-differential-pressure conditions. For high-pressure or high-temperature media, metal-seated or triple-offset butterfly valves should be selected to ensure reliable sealing.

Q3: What materials are commonly used for butterfly valves in HVAC systems?

Common materials include cast iron, carbon steel, and stainless steel. Valve bodies are often made of cast iron or ductile iron, while discs may use nickel-plated carbon steel or stainless steel to ensure corrosion and wear resistance.

Q4: Are there any installation orientation requirements for butterfly valves?

Generally, butterfly valves can be installed horizontally or vertically. However, for easier operation and maintenance, it is usually recommended to install the stem vertically and ensure the disc aligns with the flow direction when closed.

Q5: What advantages do butterfly valves have over gate valves in water treatment systems?

Butterfly valves are more compact, lighter, faster to operate, and more cost-effective. For pipelines that require frequent operation or have limited space, butterfly valves offer a more economical and efficient solution.