1. What is Electric Butterfly Valve?
An Electric Butterfly Valve is a sophisticated automation component utilized within high-precision industrial fluid control systems. This equipment integrates a rotary disc mechanism with an intelligent electric actuator, utilizing electrical energy to drive the internal closure member through a ninety-degree rotation. This integrated design allows for remote management and precise modulation of flow rates on automated production lines, eliminating the need for manual intervention or compressed air infrastructure.
As a cornerstone of modern process automation, this rotary unit is capable of interfacing with centralized control systems like a PLC or DCS. It typically consists of a high-strength body, a precision-machined disc, elastic or metal sealing seats, and a motorized actuator housing. These devices are engineered to meet global industrial standards, including ANSI, JIS, DIN, and GB, ensuring consistent performance across diverse environments. Whether the application involves handling ultrapure water or transporting aggressive chemical media, the motorized configuration offers superior control flexibility and operational stability.
2. How this Motorized Rotary Device Works?
The operation of this equipment relies on the conversion of electrical energy into mechanical torque through a series of internal gears. When a signal is sent to the actuator—typically 220V AC, 24V DC, or an analog 4-20mA control signal—the internal motor activates, driving a reduction gearbox that turns the valve stem.
The core operational process follows these stages:
- Opening Phase: The motor rotates the stem, causing the disc to move from a position perpendicular to the flow to one that is parallel. This allows the fluid to pass with a high flow coefficient (Cv) and minimal pressure drop. The intelligent actuator can stop the disc at any intermediate angle to achieve precise flow regulation.
- Closing and Sealing Phase: Upon receiving a close signal, the motor reverses the rotation. The disc edge eventually makes contact with the seat. In resilient-seated plastic models, the interference fit creates a bubble-tight seal. In high-performance triple eccentric metal designs, the offset geometry ensures that the disc only wedges into the seat at the final point of closure, significantly reducing friction and mechanical wear.
- Intelligent Feedback: Modern electric actuators are often equipped with limit switches and position transmitters. These components provide real-time feedback to the control room, indicating the exact percentage of the opening and ensuring the system operates within safety parameters.
3. Types of Electric Control Units
3.1 Material Classification and Properties
To ensure compatibility with various industrial fluids, these devices are available in a wide array of specialized materials:
- Plastic Series: Built from advanced polymers such as UPVC, CPVC, PPH, and PVDF. The PVDF variants are particularly valued for their ability to withstand temperatures ranging from -40 to 140 degrees Celsius and their extreme resistance to concentrated acids and alkaline solutions.
- Metal Series: Constructed from robust alloys including carbon steel (WCB) and stainless steel (CF8, CF8M). These are the standard choice for high-pressure systems and applications involving high-temperature steam or thermal cycles.
- Lined Series: These units feature a metal housing with an internal fluorine lining (PTFE or PFA), combining structural rigidity with complete chemical inertness for all wetted parts.
3.2 Structure and Connection Variants
- Wafer Design: A compact, lightweight version clamped between pipe flanges, ideal for space-saving installations.
- Flanged Design: Features integral flanges for direct bolting, providing extra stability for large-diameter pipelines or high-vibration environments.
- High-Performance Eccentric: Includes double or triple offset configurations that minimize contact between the seat and disc during rotation, extending the operational life in harsh services.
4. Core Advantages of the Electric System
The primary benefit of using a motorized rotary assembly is its ability to provide fine-tuned modulation without the need for an external air supply.
- Precise Flow Regulation: Intelligent electric actuators allow for linear or equal-percentage flow characteristics, making them ideal for sensitive chemical dosing or temperature control processes.
- Maintenance-Free Operation: Unlike pneumatic systems that require air filters and lubrication, modern electric units are often permanently lubricated and require minimal upkeep.
- ISO 5211 Standard: The connection between the motor and the valve body follows international mounting standards, allowing for easy upgrades or replacements of the drive unit.
| Component | Example Materials | Performance Advantage |
|---|
| Body | PVDF, WCB, CF8M, PPH | High structural integrity and chemical stability |
| Internal Disc | SS316, SS304, CPVC | Smooth surface finish reduces operating torque |
| Sealing Seats | PTFE, EPDM, FPM, RPTFE | Ensures leak-proof performance across various temperatures |
| Actuator | Die-cast Aluminum / Plastic | Intelligent positioning with manual override |
5. Industrial Applications
Because of their reliability and ease of integration into digital control loops, these devices are essential in several high-tech and traditional industries:
- Semiconductor and Lithium Battery: In these sectors, pure PVDF electric units are used to handle ultrapure water and electrolytes. The metal-free flow path prevents ion contamination, which is critical for maintaining product purity.
- Chemical and Pharmaceutical: Used for the automated distribution of aggressive reagents. The ability to precisely modulate flow rates makes these motorized units ideal for reactor feeding and solvent management.
- Water Treatment and Desalination: UPVC and CPVC equipment is widely deployed in water purification plants to handle chlorinated water and brine, where corrosion resistance and low maintenance are top priorities.
- Metallurgy and Power: Metal triple eccentric models are vital for managing high-temperature cooling water and exhaust gases in power generation facilities, where high reliability under pressure is required.
