Explosion-Proof Electric Actuators: A Comprehensive Overview
Explosion-proof electric actuators are specialized motor-driven devices designed for hazardous environments. They ensure safety by limiting parameters such as voltage, current, and energy within the circuit, preventing the generation of sparks or high temperatures that could ignite flammable gases or dust. These explosion-proof electric actuators are widely used in areas where explosive gases or dust may be present, particularly in Zone 1 and Zone 2 hazardous locations, ensuring both safety and efficiency in demanding environments.
Classification of Explosion-Proof Electric Actuators
Depending on the explosion-proof technology employed, explosion-proof electric actuators can be categorized into several types, each suited to different working environments and requirements.
1. Flameproof (Explosion-Proof) Electric Actuators
Flameproof actuators feature specially designed enclosures that isolate internal sparks or high temperatures, preventing them from reaching external hazardous areas. This design can withstand internal explosion pressures and prevent external explosions.
2. Pressurized Electric Actuators
Pressurized actuators maintain internal pressure higher than the external environment by supplying compressed gas, preventing flammable gases from entering. This design is ideal for high-risk environments, ensuring the device does not mix with external explosive gases during operation.
3. Increased Safety Electric Actuators
Increased safety actuators control the device's temperature rise, ensuring it does not cause fires or explosions in high-temperature environments. These devices often have stringent requirements for relay protection to ensure safe shutdown in abnormal conditions.
4. Non-Sparking Electric Actuators
Non-sparking actuators use special designs or materials to avoid generating sparks or arcs, preventing explosions caused by electrical faults. They are suitable for environments highly sensitive to sparks.
5. Intrinsically Safe Electric Actuators
Intrinsically safe actuators are designed to ensure that the ignition energy generated during normal operation or faults is far below the ignition energy of combustible substances. They are used in high-safety environments, such as chemical and petroleum industries.
Applicable Environments and Applications
Explosion-proof electric actuators are primarily used in Zone 1 and Zone 2 hazardous areas.
Zone 1: Environments where explosive gases or dust may be present under normal operating conditions.
Zone 2: Environments where explosive gases are not normally present but may occur due to faults or special circumstances.
These environments are commonly found in industries such as petrochemicals, pharmaceuticals, natural gas, coal, and food processing, where flammable gases or dust are handled and controlled.
Explosion-Proof Electric Actuator Structural Features
The core feature of explosion-proof electric actuators lies in their specialized circuit design and explosion-proof technology. By strictly controlling electrical components and wiring methods, they prevent the generation of sparks or high temperatures that could ignite flammable substances.
Circuit Design: Explosion-proof actuators incorporate flameproof and explosion-isolation technologies to ensure the device does not generate excessive temperatures or arcs during operation. These technologies prevent hazards even in the event of a fault.
Non-Sparking and Intrinsically Safe Designs: Non-sparking actuators avoid spark generation through special construction, while intrinsically safe actuators ensure the energy produced is insufficient to ignite surrounding combustible materials, reducing explosion risks at the source.
Protection Rating: These actuators typically have a high protection rating of IP67, making them waterproof and dustproof. For extreme environments, an IP68 rating is available to meet more demanding conditions.
Explosion-Proof Electric Actuator Design Standards
The design and production of explosion-proof electric actuators must comply with relevant explosion-proof standards and certifications to ensure safe and reliable operation in potentially explosive environments. Key standards include:
ATEX Standards: ATEX is a European directive for the safe use of equipment in explosive gas and dust environments. Actuators must comply with standards such as ATEX: II 2G ex d IIC T4 or T6, ensuring safe operation in specified temperature and gas conditions for Zone 1 and Zone 2 areas.
IECEx Standards: IECEx is an international certification system for explosion-proof equipment. Actuators must meet standards like Ex II --/2 GD 135°C (T4) to ensure safety under specific temperature and environmental conditions.
UL Standards: UL (Underwriters Laboratories) is a globally recognized safety certification body. Actuators must comply with standards such as Class I Division I Groups A, B, C, D, T5, indicating safe operation in flammable gas environments.
Advantages of Explosion-Proof Electric Actuators
Explosion-proof electric actuators offer not only safety but also the following advantages.
1. Compact and Lightweight
Compared to other actuators with similar axial torque, explosion-proof actuators are smaller and lighter, facilitating installation and maintenance. For example, an actuator with a rated output torque of 600Nm weighs only 10kg, half the size of comparable products.
2. High-Precision Control
Equipped with advanced electronic control circuits, these actuators provide precise torque adjustment and ensure positioning accuracy through electric braking technology, reducing system dead zones and self-excitation.
3. High Reliability and Long Lifespan
Using solid-state relays (SSR) and electromagnetic isolation technology, these actuators effectively resist current fluctuations and electromagnetic interference, enhancing stability and reliability while reducing maintenance efforts.
4. Protection Features
Explosion-proof actuators feature comprehensive overload and overheating protection. With a protection rating of IP67 (and optional IP68 for harsher conditions), they are well-suited for complex environments.
Conclusion
Explosion-proof electric actuators are efficient and safe driving devices widely used in industries such as petrochemicals, natural gas, and pharmaceuticals. Their design and structure fully consider potential hazardous environments, ensuring safe operation in high-risk areas. With high-precision control, reliability, and innovative design, explosion-proof electric actuators have become indispensable in modern industrial applications, whether in small devices or high-power systems.
