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1. What Is an Explosion-Proof Actuator?
An explosion-proof actuator is a device designed to operate in hazardous environments without igniting flammable substances in the surrounding atmosphere.
The Principle of Explosion-Proof Enclosure:
Contrary to what the name might suggest, explosion-proof actuators are not designed to prevent explosions inside the housing. Instead, they are engineered to:
Contain the explosion: If flammable gases enter the enclosure and ignite, the housing is strong enough to withstand the pressure without rupturing.
Cool escaping gases: Any flames or hot gases that escape must pass through specially designed flame paths (tightly controlled gaps) that cool them below the ignition temperature of the external atmosphere.
Result: An internal explosion is contained and safely extinguished before it can ignite the surrounding hazardous area.
2. Hazardous Area Classifications
To select the right explosion-proof actuator, you must understand the hazard classification of your facility.
International System (IECEx / ATEX)
| Zone | Definition | Example |
|---|---|---|
| Zone 0 | Explosive atmosphere present continuously or for long periods | Inside storage tanks |
| Zone 1 | Explosive atmosphere likely to occur in normal operation | Pump rooms, loading areas |
| Zone 2 | Explosive atmosphere unlikely and only for short periods | Areas adjacent to Zone 1 |
Gas Groups:
Group I: Mining (methane)
Group IIA: Propane (typical industrial gases)
Group IIB: Ethylene (chemical plants)
Group IIC: Hydrogen, Acetylene (most explosive)
Temperature Classes (T-Ratings):
| Class | Maximum Surface Temperature |
|---|---|
| T1 | 450°C |
| T2 | 300°C |
| T3 | 200°C |
| T4 | 135°C |
| T5 | 100°C |
| T6 | 85°C |
The actuator's surface temperature must never exceed the ignition temperature of the surrounding gases.
North American System (NEC / CEC)
| Class | Division | Description |
|---|---|---|
| Class I | Division 1 | Flammable gases or vapors present under normal conditions |
| Class I | Division 2 | Flammable gases or vapors present only under abnormal conditions |
| Class II | Division 1 | Combustible dusts present under normal conditions |
| Class II | Division 2 | Combustible dusts present only under abnormal conditions |
| Class III | - | Ignitable fibers/flyings |

3. Why Pneumatic Actuators Are Preferred for Hazardous Areas
Electric actuators contain components (motors, switches, circuit boards) that can spark during normal operation. Making them explosion-proof requires heavy, expensive enclosures and specialized design.
Pneumatic actuators, like the KINKO JAT-SR Series, offer a simpler solution:
Advantages of Pneumatic Actuators in Hazardous Areas:
| Feature | Benefit |
|---|---|
| No Electrical Components | No spark sources in the actuator itself |
| Operates on Compressed Air | Safe in explosive gas and dust environments |
| Simple Construction | Fewer failure points than complex electric drives |
| Spring Return Options | Fail-safe operation without electricity |
| ATEX Certified Materials | Non-sparking materials and coatings available |
The KINKO JAT-SR Advantage:
ATEX-certified models available for Zone 1 and Zone 2 applications.
Optional stainless steel construction for corrosive hazardous environments.
Conductive coatings to prevent static buildup.
Spring return models provide fail-safe operation without electrical power.
4. KINKO JAT-SR Series for Hazardous Areas
The JAT-SR Series pneumatic actuators are ideal for explosion-proof applications when properly specified with the right options.
Standard Features Relevant to Hazardous Areas:
| Feature | Benefit for Hazardous Areas |
|---|---|
| Rack and Pinion Design | Reliable, predictable operation |
| Double Acting and Spring Return | Fail-safe options without electricity |
| Anodized Aluminum Body | Corrosion resistant, non-sparking surface |
| Stainless Steel Fasteners | Prevent corrosion-induced sparking |
| Namur Mounting Interface | Direct mount of pilot solenoids (which must be separately certified) |
ATEX Certification Options:
KINKO offers JAT-SR variants certified for use in:
II 2G Ex h IIC T6 Gb (Gas, Zone 1)
II 2D Ex h IIIC T85°C Db (Dust, Zone 21)
Temperature Class T6 (85°C max surface temperature)
5. Applications Across Hazardous Industries
A. Oil & Gas Upstream (Wellheads, Platforms)
Applications:
Emergency shutdown valves (ESD)
Wing and master valves on Christmas trees
Flow control manifolds
Separator inlet/outlet valves
Why KINKO JAT-SR:
Spring return models provide fail-safe closure on air loss.
ATEX Zone 1 certification for wellhead areas.
Corrosion-resistant options for offshore environments.
B. Refineries and Petrochemical Plants
Applications:
Burner management systems
Isolation valves on process units
Loading arms and truck racks
Flare gas recovery systems
Why KINKO JAT-SR:
Fast stroking speeds for emergency isolation.
SIL 3 capable for safety instrumented systems.
Wide temperature ranges for process heat.
C. Chemical Processing
Applications:
Reactor feed isolation
Solvent transfer systems
Hazardous material storage
Batch processing with flammable chemicals
Why KINKO JAT-SR:
Non-sparking materials prevent ignition.
Compatible with corrosive atmospheres.
Simple maintenance reduces exposure risk.
D. Pharmaceutical Manufacturing
Applications:
Solvent handling systems
Reactor isolation
Clean-in-place (CIP) systems with flammable cleaning agents
Why KINKO JAT-SR:
Clean design with minimal crevices.
Options for cleanroom compatibility.
Reliable operation in classified pharmaceutical areas.
E. Mining and Mineral Processing
Applications:
Coal handling (dust explosion risk)
Slurry valves in processing
Ventilation controls
Dewatering systems
Why KINKO JAT-SR:
Dust ignition protection (ATEX for dust).
Robust construction for harsh mining environments.
High torque for large valves.
F. Paint and Coating Facilities
Applications:
Solvent delivery systems
Mixing vessel isolation
Ventilation dampers
Why KINKO JAT-SR:
Conductive options prevent static discharge.
Reliable operation with frequent cycling.
Compact design for tight spaces.
G. Grain Handling and Food Processing
Applications:
Dust collection systems
Grain transfer valves
Bin isolation gates
Why KINKO JAT-SR:
Dust ignition protection.
Food-grade lubricants available.
Washdown-capable options.

6. Electric Options for Hazardous Areas
While pneumatic is preferred, some applications require electric actuation. KINKO offers KK Series electric actuators with explosion-proof enclosures for specific needs.
When to Choose Explosion-Proof Electric (KK Series Ex):
No compressed air available on site.
Precise modulating control required.
Remote monitoring and IIoT connectivity essential.
Battery backup fail-safe needed.
KK Series Ex Features:
Flameproof enclosure (Ex d) certified.
ATEX/IECEx for Zone 1 and Zone 2.
IP66/IP68 protection.
Integrated position feedback.
Modbus and PROFINET communication.
7. Selection Guide: Choosing the Right Explosion-Proof Actuator
| Application Factor | Recommended Choice |
|---|---|
| Zone 0 (Continuous hazard) | Specially certified pneumatic only (consult factory) |
| Zone 1 (Normal operation hazard) | KINKO JAT-SR ATEX (pneumatic) or KK Series Ex (electric if required) |
| Zone 2 (Abnormal condition hazard) | KINKO JAT-SR (pneumatic) or standard KK with care |
| Gas Group IIC (Hydrogen) | Highest certification level required |
| Dust hazard (Zone 21/22) | KINKO JAT-SR with dust ignition protection |
| Fail-safe required | JAT-SR Spring Return (pneumatic - no power needed) |
| Modulating control needed | KK Series Ex (electric) |
| No compressed air available | KK Series Ex (electric) |
8. Critical Considerations for Explosion-Proof Installations
A. Entire System Must Be Certified
The actuator alone is not enough. All components in the hazardous area must be suitably rated:
Solenoid valves (must be ATEX-rated for the zone)
Limit switch boxes (must be explosion-proof)
Positioners (must be certified)
Cabling and conduits (must meet installation standards)
B. Installation Matters
Even certified equipment can become unsafe if improperly installed:
Conduit seals must be installed correctly.
Cable glands must be appropriate for the zone.
Grounding and bonding must be verified.
C. Regular Inspection
Explosion-proof equipment requires periodic inspection to ensure:
Flame paths are not damaged or corroded.
Gaskets and seals are intact.
No unauthorized modifications have been made.
9. KINKO Explosion-Proof Product Comparison
| Feature | JAT-SR Series (Pneumatic) | KK Series Ex (Electric) |
|---|---|---|
| Certification | ATEX / IECEx (II 2G/2D) | ATEX / IECEx Ex d |
| Gas Groups | IIA, IIB, IIC (depending on model) | IIA, IIB, IIC |
| Temperature Class | T6 (85°C) available | T4 / T5 / T6 options |
| Zones | 1, 2, 21, 22 | 1, 2 |
| Power Source | Compressed air | Electric |
| Control Type | On/Off (with solenoid) | On/Off or Modulating |
| Fail-Safe | Built-in spring return | Battery backup module |
| Best For | Simple on/off, high reliability, no power needed | Precise control, smart monitoring |
Conclusion
Explosion-proof actuators are not optional in hazardous areas—they are a critical safety requirement. Whether you are automating valves on an offshore platform, a chemical reactor, or a grain handling facility, choosing the right certified actuator protects both your personnel and your facility.
KINKO offers comprehensive solutions for hazardous area actuation:
JAT-SR Series Pneumatic Actuators: The preferred choice for most hazardous areas—simple, reliable, ATEX-certified, with fail-safe spring return options.
KK Series Ex Electric Actuators: For applications requiring precise control or where compressed air is unavailable.
Have a hazardous area application?
Contact KINKO today with your zone classification, gas group, and valve details. Our engineers will recommend the right certified solution for your safety requirements.
Ivan (Mobile:+86-18968769287)
WhatsApp:+86-13579991606
Wechat:+86-18968769287
Website:www.kinko-flow.com
ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD

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