In modern industrial production, valves are not only core control elements in fluid transport systems but also critical equipment for ensuring operational safety. With the development of industrial automation, electric ball valves have become widely used due to their simple operation, rapid opening and closing, and precise control. However, in flammable and explosive environments such as oil, chemical, natural gas, and coal mining industries, ordinary electric ball valves cannot meet safety requirements, giving rise to the widespread adoption of explosion-proof electric ball valves. This article provides an in-depth introduction to the structural features, working principles, application scenarios, and selection considerations of explosion-proof electric ball valves, helping enterprises better understand this essential industrial control device.
An explosion-proof electric ball valve is an automated control device that integrates a ball valve with an electric actuator, specifically designed for fluid control in flammable and explosive environments. It operates by receiving current signals (such as 4–20 mA) or voltage signals (such as 1–10 V DC) to rotate the ball 0–90°, achieving open, close, or regulating functions. Compared with ordinary electric ball valves, explosion-proof models are stricter in terms of safety performance, protection level, and material selection, effectively preventing the risk of sparks that could cause explosions.The main components include:
- Electric Actuator: Fully integrated electromechanical structure with built-in servo control, switch signal feedback, position indication, and manual operation functionality.
- Ball Valve Body: Smooth ball channel with high flow capacity, suitable for high-viscosity media or media containing fibers or solid particles.
- Control System: Can receive either switch or analog signals for automated control.
- Explosion-Proof Housing: Made of hard aluminum alloy with anodized surface treatment, corrosion-resistant, and waterproof up to IP67.
Explosion-proof electric ball valves not only offer a high-precision domestic alternative to imported equipment but are also widely applied in oil and chemical industries, metallurgy, light industry, water treatment, and coal mining.
Explosion-proof electric ball valves are designed with safety, reliability, and ease of operation in mind. Key features include:
The explosion-proof electric ball valve uses a fully electronic electric actuator, offering the following advantages:
- Integrated Electromechanical Design: Built-in servo operation and switch signal position feedback allow precise ball angle control.
- Manual Operation: In the event of a power outage or abnormal situation, the valve can be manually operated via a clutch handle.
- Overheat Protection: The motor includes a thermal protection switch to prevent stall or overload damage.
- High Torque and Low Inertia: The closed-cage rotor motor provides high torque, small size, and low inertia, ensuring smooth and reliable operation.
- IP67 Protection: Dustproof and waterproof, suitable for outdoor and harsh environments.
The ball valve features a concave wheel design with a smooth channel that prevents medium deposition and offers:
- Simple structure and lightweight for easy installation and maintenance.
- Excellent sealing performance, zero leakage, and durable valve seat isolation in fully open or fully closed states.
- Wide applicability, capable of handling high-viscosity, fiber-containing, or particulate media.
- High corrosion resistance due to material selection and surface treatment.
The housing is made of hard aluminum alloy with anodized and polyester powder coating treatment for corrosion and high-temperature resistance. The handwheel design ensures reliable, effortless operation without power, and the actuator can automatically reset.
- Limit Switches: Mechanical and electronic bidirectional limits provide accurate and reliable operation.
- Torque Switches: Overload protection prevents motor damage.
- Dual Worm Gear Mechanism: High transmission efficiency, large torque, low noise (≤50 dB), and stable durability.
The high-integration control board with low power consumption, combining analog circuitry and microcontroller control, allows:
- Automated on/off and proportional adjustment
- Switching between electric and manual operation
- Compatibility with multiple power sources and control signals (AC380V/220V, DC24V, 4–20 mA, or 1–10 V DC)
The core working principle of an explosion-proof electric ball valve is based on electric drive and rotary control:
- Signal Input: The controller calculates the required rotation angle based on received current or voltage signals.
- Motor Drive: The fully enclosed rotor motor outputs torque, driving the ball through worm or other transmission mechanisms.
- Position Feedback: The servo system sends the actual valve position back to the controller, ensuring precise regulation.
- Open/Close Operation: The ball rotates 0–90° to achieve full open or full close; in proportional control mode, any angle can be set to regulate flow.
- Manual Operation: In case of power failure, the clutch handle allows manual valve operation for safe emergency control.
This electromechanical integration allows the explosion-proof electric ball valve to meet both automated control and emergency operational needs.
The explosion-proof rating determines the valve's safety in hazardous environments. Common ratings include:
- Exd: Flameproof type, suitable for flammable gas environments, isolating internal explosions from the external environment.
- Exe: Increased safety type, using housing protection to prevent sparks.
- Exi: Intrinsically safe type, limiting current and voltage to prevent ignition.
In industrial applications, common ratings are Exd IIB T4, Exd II CT5, and Exd II CT6.
Explosion-proof electric ball valves can reliably operate under:
- High or low temperatures (-20℃ to over 450℃)
- High humidity or outdoor environments (IP67 waterproof and dustproof)
- Flammable gas or dust environments
- Corrosive environments such as marine or dockside areas
- High vibration or high fire-risk locations
- Nuclear power plants and radioactive material environments
Materials and actuators may be adjusted to meet specific environmental demands for stable operation.
Explosion-proof electric ball valves are suitable for various scenarios requiring safe and reliable control, especially in flammable and explosive industrial environments. Major applications include:
- Oil and Gas Industry: Controlling the opening and closing of oil and gas pipelines, suitable for high-pressure, large-diameter pipelines to ensure safe transport.
- Chemical Industry: Handling corrosive media, fibrous particles, and suspensions, enabling automated flow regulation.
- Coal Mining and Dust-Prone Environments: High explosion-proof rating prevents dust explosion risks, ensuring mine operation safety.
- Water Treatment and Sewage Networks: Controls flow, pressure, and water quality with high automation and easy operation.
- Shipbuilding and Light Industry: Corrosion-resistant, moisture-proof, and salt-spray resistant for complex marine and hot-humid environments.
- Energy and Power Industry: Pipeline control in power plants and automated heating system adjustment, ensuring operational efficiency and safety.
- Safety and Reliability: High explosion-proof rating, fire-resistant and anti-static electrical components; Built-in thermal and overload protection to prevent motor damage; Manual operation ensures safe operation during power failure or abnormal conditions
- Ease of Operation: Rapid opening and closing with precise regulation; Built-in servo system allows proportional control; Clear indicator design for easy on-site observation
- Compact and Durable Structure: Fully enclosed rotor motor with small size, high torque, and low inertia; Wear-resistant and corrosion-resistant ball and seat materials; Aluminum alloy housing with anodized treatment, IP67 protection
- High Applicability: Suitable for high-temperature, high-pressure, and large-diameter pipelines; Handles high-viscosity, fiber-containing, or particulate media; Compatible with various control signals (4–20 mA, 0–10 V, etc.)
- Easy Maintenance: Anti-loosening bolt design for convenient housing assembly and disassembly; Internal desiccant prevents condensation; High-precision worm gear drive requires minimal lubrication and ensures stable operation
When selecting an explosion-proof electric ball valve, consider:
- Explosion-Proof Rating: Choose according to the type of flammable gas or dust in the working environment.
- Valve Body Material: Consider corrosion, temperature, and particle characteristics to select durable materials.
- Electric Actuator Performance: Including power type, voltage level, control signal type (switch or analog), torque, and protection features.
- Operating Environment: Indoor/outdoor, humid, dusty, salt-spray, vibration, or extreme temperatures.
- Control Requirements: Automation level—simple on/off control or proportional adjustment with on-site operation.
- Pipeline Parameters: Pipe diameter, flow rate, pressure, and fluid viscosity to ensure efficient and stable operation.
- Regularly inspect motors, limit switches, and indicators to ensure sensitive operation.
- Maintain waterproofing and humidity protection; periodically clean internal deposits.
- Check sealing surfaces and ball wear regularly in high-temperature, high-pressure, or corrosive environments.
- Keep the explosion-proof performance of electrical components intact; avoid unauthorized modifications.
- Always cut off power and manually reset the handwheel when disassembling or maintaining the valve.
Explosion-proof electric ball valves combine safety, precise control, and ease of operation in industrial automation. They operate safely in flammable and explosive environments while automatically regulating flow, pressure, and temperature, with broad applications in oil, chemical, coal mining, water treatment, and power industries. The electromechanical integration, manual emergency operation, precise stroke control, and high protection level make them a critical tool in industrial automation control systems.
Proper selection, certified explosion-proof rating, and reasonable maintenance and operation ensure the full performance potential of explosion-proof electric ball valves, achieving safe, efficient, and intelligent fluid control in industrial sites.
