In the vast system of industrial fluid control, butterfly valves stand out for their high efficiency and economy, becoming a “key role” in many fields such as chemical industry, energy, water supply and drainage. However, in order to make butterfly valves play the best performance in actual working conditions, scientific selection is an important link that cannot be avoided. This requires not only accurate matching of valve performance and application requirements, but also consideration of operational convenience and economic cost. Next, starting from the core elements such as medium characteristics, working conditions, and sealing requirements, we will disassemble the full process strategy of butterfly valve selection for you.
Medium characteristics: the primary “ruler” for selection
The medium characteristics are like the “compass” of butterfly valve selection, guiding the first step of selection. For liquid media, flow rate is a key indicator that cannot be ignored. It is generally recommended to control the flow rate within 5m/s to avoid cavitation caused by excessive flow rate and damage to the internal structure of the valve. When the medium is corrosive, the selection of valve body material is particularly critical. Stainless steel (such as SUS316L), polytetrafluoroethylene and other corrosion-resistant materials can effectively resist medium erosion and extend the service life of the valve.
Anchoring temperature and pressure: the cornerstone of adapting to working conditions
The temperature and pressure parameters of the medium directly determine the “hardware configuration” of the butterfly valve. In terms of temperature, ductile iron butterfly valves are suitable for working conditions where the medium temperature is not higher than 350°C, while stainless steel, with its excellent resistance to high temperature and high pressure, is an ideal choice for high temperature and high pressure scenarios. In terms of pressure, the nominal pressure of the butterfly valve must be accurately matched to the actual working pressure. Only in this way can the valve be ensured to be safe during operation and avoid hidden dangers such as leakage and bursting.
Butterfly valve type selection: different structures correspond to different needs
Middle line Butterfly valve (concentric butterfly valve)
As a “popular model” in the market, the center line butterfly valve performs well in low-pressure, large-diameter and relatively loose leakage requirements due to its simple structure and affordable price. It is often used in water and air flow regulation systems.
Double eccentric Butterfly valve
The unique double eccentric design greatly reduces the friction between the valve seat and the butterfly plate, which is particularly suitable for medium-pressure conditions. It can significantly improve the durability of the valve and is suitable for scenarios with high requirements on service life.
Triple Eccentric Butterfly Valve
It is known as the “all-round player” in the butterfly valve industry and is designed for extreme working conditions such as high pressure, high temperature, and strong corrosion. Its innovative three-eccentric structure achieves an excellent sealing effect of “the tighter it closes”, while effectively reducing the operating torque, taking into account both sealing performance and operating efficiency.
Drive mode adaptation: the key to convenient operation
The driving mode of the butterfly valve directly affects its usage experience and degree of automation:
Manual drive
It is directly operated by a handwheel or a wrench, with a simple structure and low cost. It is suitable for small-diameter valves and occasions with low operating frequency. The valve can be easily opened and closed without a complex control system.
Electric drive
With the help of electric actuators, remote control and automated operation can be achieved, and it can be seamlessly connected to control systems such as PLC and DCS. It is widely used in modern industrial automation production lines to meet the needs of intelligent production.
Pneumatic drive
Using compressed air as the power source, it has the characteristics of quick response and high output force. It is especially suitable for emergency shut-off scenarios that require rapid opening and closing, or application environments with extremely high safety performance requirements, to ensure production safety.
Sealing surface material selection: the key to ensure sealing performance
The selection of sealing surface material is directly related to the sealing performance of the butterfly valve and the applicable medium type:
Hard sealing material
For example, metal rings have excellent resistance to high temperature and high pressure and can maintain good sealing effects under harsh working conditions. They are a reliable choice for high temperature and high pressure scenarios.
Soft sealing material
Like rubber, polytetrafluoroethylene, etc., it has excellent corrosion resistance and is suitable for conveying corrosive, highly toxic or highly hazardous media, effectively preventing media leakage and protecting production safety and environmental safety.
Connection considerations: “Interface” that matches the piping system
Different piping systems have different requirements for butterfly valve connection methods:
Wafer connection
With the advantages of easy installation and low cost, it has become a favorite for small-diameter pipelines. The valve is clamped between the pipelines through two flanges, making installation and disassembly very convenient.
Flange connection
It is suitable for large-diameter and high-pressure pipelines, has the characteristics of firm connection and good sealing performance, can withstand high pressure and torque, and ensure the stable operation of the pipeline system.
Clamp connection
With its characteristics of quick installation and easy disassembly, it is highly favored in the food, medicine and other industries, meeting the special needs of these industries for hygiene and convenience.
Valve body material selection: the final decision of comprehensive working conditions
The valve body material of the butterfly valve needs to be determined based on the medium characteristics and working conditions. Among the common materials, ductile iron is suitable for normal temperature water transportation, cast steel performs well under medium and high pressure conditions, and stainless steel has become the first choice for conveying corrosive media due to its excellent corrosion resistance. In addition, special materials such as UPVC, CPVC and polytetrafluoroethylene also play an irreplaceable role under specific working conditions.
Practical example: In-depth analysis of the selection process
Take a chemical project as an example, it needs to transport corrosive liquid with pH=2, pressure 1.0MPa, temperature 80℃, flow rate 100m’/h. The specific selection steps are as follows:
- Material lock: In view of the corrosiveness of the medium, stainless steel valve body (such as SUS316L) is preferred to resist medium erosion from the source of the material.
- Type selection: Facing high-pressure working conditions, the three-eccentric metal hard-sealed butterfly valve becomes the best choice. Its excellent sealing performance and pressure resistance can ensure stable operation.
- Flow rate verification: Assuming that the pipe diameter is DN200, the calculated flow rate is about 3.5m/s, which meets the flow rate control requirements and avoids cavitation risks.
- Drive determination: Considering the automation requirements of the project, an electric actuator is selected, and the required torque z240N·m is calculated according to the working conditions to ensure stable and reliable valve operation.
Butterfly valve selection is a systematic project, and every selection link is crucial. Only by comprehensively considering various factors can the most suitable butterfly valve be matched for the actual working conditions, so that it can play the maximum performance in the field of fluid control.
For more Butterfly Valve knowledge, Please click《What is a Butterfly valve? The “Flow commander ” of industrial pipelines》
Butterfly valves, as the core flow control guards of industrial pipelines, use simple mechanical aesthetics to connect and disconnect pipelines in every household from deep-sea, medical, aerospace and other fields with complex working conditions. JH -Valve Manufacturing, relying on the strict standards of AI prediction system, nano-level coating and aviation industry standards, pushes the reliability of butterfly valves to the extreme. In the extreme cold of deep space at -200℃ or the heat wave of lava at 550℃, JH Butterfly Valves protect the endless flow of industrial lifeline with absolute precision of zero leakage. Choosing JH is not only choosing a valve, but also choosing the technological hegemony of fluid control in the next thirty years. Here, every rotation is a breakthrough of the limit, and every opening and closing is an eternal promise of industrial civilization.
