Quick Summary
Butterfly valves are core components of fluid control in large-diameter pipelines, widely used in industries. This article analyzes key selection considerations for butterfly valves under actual operating conditions, highlighting their core advantages in large-diameter pipelines and providing a reference for enterprises to optimize the performance of their fluid control systems.
What is a butterfly valve?
A butterfly valve is a quarter-turn valve that controls fluid flow by changing the cross-sectional area of the flow channel through a rotating disc . It gets its name from its resemblance to butterfly wings when the disc is fully open. It features a simple structure, fast opening and closing speed, and convenient installation , making it particularly suitable for the high-efficiency flow management needs of large-diameter pipelines of DN50 and above.
Five Key Factors in Choosing a Butterfly Valve
1. Pipe size matches valve size
- For large-diameter pipelines (usually DN50 and above, or more than 2 inches), butterfly valves of the same specification should be selected first to avoid flow loss (such as increased local resistance) or sealing failure caused by size deviation.
- Butterfly valves have significant advantages in large-size applications: they can be designed for sizes above DN1000 without significantly reducing control accuracy due to increased diameter; in contrast, gate valves and ball valves are prone to operational jamming in large-size models due to excessively long valve stems and heavy valve cores.
2. Pressure and temperature compatibility
Select the appropriate type of butterfly valve based on the actual operating conditions of the pipeline. The core parameters must match the medium conditions.
| Operating conditions | Recommended butterfly valve type | Rated pressure range | Temperature range | Adaptation scenario examples |
| Low pressure, room temperature | Resilient sealing butterfly valve | PN1.0~PN10 | -10℃~120℃ | Water pipes and irrigation systems |
| High pressure and high temperature | Metal-sealed butterfly valve | PN16~PN42 | -20℃~400℃ | Oil transportation, steam pipelines |
- Large-diameter pipelines often involve high pressure, so it is important to check the valve body material (such as cast steel or stainless steel) and the temperature and pressure resistance of the seals to prevent leakage during long-term use.
3. Valve Material Selection
The durability and corrosion resistance of butterfly valves made of different materials vary significantly. For large-diameter pipelines, the selection of valves should be based on the characteristics of the medium and the operating environment.
| Material type | Core Advantages | Corrosion resistance | Adapted scenarios |
| cast iron | Low-cost and high-cost performance | Poor | Low pressure, normal temperature, non-corrosive media (municipal sewage, irrigation) |
| Stainless steel (304/316) | Corrosion-resistant and resistant to high and low temperatures | excellent | Corrosive media (chemical wastewater, seawater), high temperature, and high-pressure pipelines |
| Ductile iron | It has higher strength than cast iron and better toughness. | medium | Large-diameter low-pressure pipelines (main water supply pipes, HVAC systems) |
4. Key to Leakage Prevention
The sealing mechanism directly affects the leak-proof performance of the butterfly valve and must be selected according to the priority of operating conditions.
- Elastic seals (such as EPDM and NBR rubber): They offer good sealing performance (leakage ≤0.1%) and low cost, making them suitable for low-pressure and normal-temperature applications. However, attention should be paid to the upper limit of the rubber’s temperature resistance (usually ≤120℃).
- Metal seal: Resistant to high and low temperatures (-20℃~400℃), wear-resistant, suitable for high pressure, high temperature, and particulate media scenarios (coal powder transportation, high temperature steam pipelines), making it the preferred choice for large-diameter industrial pipelines.
- PTFE seals: combine corrosion resistance (acid and alkali resistance) with sealing performance, making them suitable for pipelines carrying strong chemical media.
5. Operating Procedures
- Manual operation: Controlled by handwheel or handle, suitable for small diameter (below DN50) and low frequency switching scenarios (bypass pipes of small water treatment equipment).
- Electric/pneumatic operation: Preferred for large-diameter pipelines (DN300 and above), supports remote control and automatic adjustment, and can be connected to PLC systems (such as unmanned oil pipeline stations and water plant control systems), reducing labor costs and improving operational safety.
- Electric butterfly valve: suitable for scenarios requiring precise flow regulation (such as percentage control) and stable power supply;
- Pneumatic butterfly valve: suitable for scenarios with high risk of power failure (such as oil well sites) and requiring rapid switching (response time ≤ 5 seconds).
Six Core Advantages of Butterfly Valves in Large-Diameter Pipelines
1. Compact and lightweight, saving installation space
The structural design of butterfly valves makes their volume only 1/3 to 1/2 that of gate valves and ball valves of the same specifications, and their weight is lighter (e.g., a DN500 butterfly valve weighs about 80kg, while a gate valve of the same specifications weighs about 320kg). They are especially suitable for scenarios with limited space (underground pipe wells, chemical workshops with dense equipment), which can reduce the installation footprint by more than 30% and reduce transportation and hoisting costs.
2. Fast flow control and high response efficiency
Featuring a quarter-turn design, it offers short switching times, enabling rapid flow adjustment or emergency media shut-off, and is suitable for the “rapid response” requirements of large-diameter pipelines, such as:
- Emergency water supply regulation at waterworks: Valve opening adjustment must be completed within 1 minute.
- Oil pipeline accident shutdown: The medium must be cut off within 10 seconds to prevent the leak from spreading.
3. Lower cost and outstanding cost performance.
Compared to gate valves and ball valves, butterfly valves have a significant cost advantage in large-diameter applications:
- Procurement cost: The price of a DN1000 butterfly valve is approximately 50%~60% of that of a ball valve of the same specification, and 40%~50% of that of a gate valve.
- Installation cost: The lightweight and simple structure can reduce investment in hoisting equipment and shorten installation time by more than 30% compared to gate valves.
- Maintenance costs: With fewer core components and a lower probability of failure, the maintenance costs are 20% to 40% lower than those of other valves.
4. Multifunctional compatibility, wide range of applications
It can cover a variety of media such as liquids, gases, and slurries, and is suitable for a wide range of pressures (PN1.0~PN42.0) and temperatures (-196℃~600℃), meeting the needs of large-diameter pipelines in many industries.
- Water treatment: raw water inlet, sedimentation tank effluent regulation;
- Oil and gas: crude oil transportation, natural gas gathering and transmission;
- Chemical industry: transportation of acid and alkali solutions and solvents;
- HVAC: Flow control of water and air systems for air conditioning in large buildings.
5. Simple maintenance, reducing downtime.
- Easy component replacement: Core components, such as valve stem and seal,s are easy to disassemble and can be replaced without disassembling the entire valve. Maintenance efficiency is 50% higher than that of gate valves (e.g., the seal replacement of a DN600 butterfly valve takes only 2 hours, while that of a gate valve takes 6 hours).
- Routine maintenance is simple: only regular (quarterly) cleaning of impurities in the valve body and lubrication of the valve stem (adding special grease) are required. No complicated testing equipment is needed, making it suitable for the “long-term stable operation” requirements of large-diameter pipelines (such as uninterrupted water supply throughout the year in municipal water supply trunk lines).
6. Reliable sealing and strong cutting performance.
When paired with high-quality seals (such as metal seals and PTFE seals), zero leakage can be achieved, and the sealing performance decays slowly over long-term use. It is especially suitable for large-diameter pipelines carrying high-risk media (toxic chemical liquids, natural gas transportation) to ensure system safety.
Typical Application Scenarios of Butterfly Valves in Large-Diameter Pipelines
| Industry Sector | Application areas | Recommended butterfly valve specifications | Key Selection Points |
| water treatment plant | Raw water inlet, sedimentation tank effluent | DN500~DN2000 | Ductile iron material, elastic seal, electric operation |
| Oil and Gas | Crude oil trunk pipelines and natural gas gathering and transportation | DN800~DN1500 | Cast steel valve body, metal seal, pneumatic operation |
| Chemical processing plant | Acid and alkali solution delivery | DN300~DN800 | 316 stainless steel, PTFE seal, electrically operated |
| HVAC system | Large building air conditioning water pipes | DN200~DN600 | Ductile iron, elastic seal, electric adjustment |
FAQ
- Q: Should I choose a butterfly valve or a gate valve for large-diameter pipelines? Which one is more suitable?
A: Butterfly valves are the preferred choice. Butterfly valves are small, low-cost, and easy to maintain, making them suitable for flow control requirements in large-diameter pipelines; gate valves, while providing good sealing, are large and expensive, making them more suitable for small-diameter, high-pressure applications.
- Q: What material should the butterfly valve be made of for a DN300 large-diameter pipeline?
A: It needs to be selected according to the medium.
- Municipal water supply and HVAC: Ductile iron (low cost, strength meets requirements);
- Corrosive chemical media (such as hydrochloric acid, seawater): 316 stainless steel (corrosion resistant);
- High-temperature steam pipeline: cast steel (temperature and pressure resistant).
- Q: What should I do if my large-diameter butterfly valve is leaking? How can I fix it?
A: The solution involves three steps:
① Inspect the seals: If the elastic seal is aged, replace it with the same type of EPDM/PTFE seal; if the metal seal is worn, grind the sealing surface or replace the sealing pair.
② Check installation accuracy: Ensure the valve body is coaxial with the pipeline (deviation ≤ 0.5mm) to avoid uneven sealing force;
③ Check the operating method: Avoid operating beyond the range (such as using a low-pressure sealing butterfly valve in a high-pressure scenario).
- Q: Which should I choose for large-diameter pipelines: an electric butterfly valve or a pneumatic butterfly valve?
A: Select according to scenario priority:
- High risk of power outage and need for rapid switching: Pneumatic butterfly valve (driven by compressed air, no power supply required);
- Precise flow regulation and stable power supply are required: Electric butterfly valve (supports 0~10V signal regulation, accuracy ±1%).
