Which has a higher protection level, BT4 or CT6? How to choose between a positioner and a limit switch valve?
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CT6 has a higher explosion-proof rating than BT4, as it covers more explosive gas groups and has a lower maximum surface temperature (85°C vs. 135°C for BT4). For valve positioners and limit switches, select protection ratings (IP) and explosion-proof ratings (Ex) based on environmental hazards, and choose Kinko products with certified ratings for reliable performance.
1. BT4 vs. CT6: Explosion-Proof Rating Comparison
| Feature | BT4 | CT6 |
|---|---|---|
| Explosive Gas Group | IIB (e.g., ethylene) | IIC (e.g., hydrogen, acetylene) |
| Max Surface Temperature | 135°C | 85°C |
| Coverage | Cannot be used in IIC environments | Can cover IIB environments |
| Safety Level | Lower | Higher (T6 is the highest temperature class) |
2. How to Select Protection Ratings for Valve Positioners and Limit Switches
- IP Rating (Ingress Protection):
- IP65: Dust-tight, low-pressure water jet-proof; suitable for general indoor industrial areas.
- IP67: Dust-tight, temporary immersion-proof; ideal for outdoor, humid, or dusty locations.
- IP68: Dust-tight, continuous immersion-proof; for underwater or extreme wet conditions.
- Explosion-Proof Rating (Ex):
- Non-hazardous areas: No explosion-proof rating required.
- Zone 1/2 (gas): Select Exd (flameproof) or Exi (intrinsically safe) with appropriate gas group (IIB/IIC) and temperature class (T4–T6).
- Zone 21/22 (dust): Choose Ex t (dust ignition-proof).
- Key Selection Steps:
- Assess the environment: Identify gas/dust hazards, humidity, dust levels, and temperature range.
- Match IP rating to environmental conditions.
- Select Ex rating based on hazardous area classification and gas/dust type.
- Verify certifications: ATEX, IECEx, UL, et
3. Kinko Positioner and Limit Switch Recommendations
- Kinko Valve Positioner (Model: KPV Series):
- IP Rating: IP67 (standard), IP68 (optional).
- Explosion-Proof Rating: Exd IIC T6 (suitable for Zone 1/2, IIC gas group).
- Features: NAMUR standard mounting, stainless steel components, wide temperature range (-40°C to +80°C).
- Kinko Limit Switch (Model: KLS Series):
- IP Rating: IP67 (standard), IP68 (optional).
- Explosion-Proof Rating: Exd IIC T6 (certified for Zone 1/2, IIC gas group).
- Features: ISO 5211 mounting, visual position indicator, multiple contact configurations (1NC+1NO).
4. Application Scenarios & Kinko Product Selection
| Scenario | Recommended IP Rating | Recommended Explosion-Proof Rating | Kinko Product |
|---|---|---|---|
| General Indoor (Non-hazardous) | IP65 | None | KPV Series, KLS Series |
| Outdoor/Coastal (Humid, Corrosive) | IP67 | None | KPV Series (IP67), KLS Series (IP67) |
| Petrochemical Plant (Zone 1, IIC Gas) | IP67 | Exd IIC T6 | KPV Series (Exd IIC T6), KLS Series (Exd IIC T6) |
| Offshore Platform (Underwater Immersion) | IP68 | Exd IIC T6 | KPV Series (IP68 option), KLS Series (IP68 option) |
5. Key Considerations
- Ensure the selected rating covers the worst-case environmental conditions.
- Verify third-party certifications (ATEX, IECEx, UL) for explosion-proof ratings.
- Match the product’s temperature range to the operating environment.
- Choose Kinko products for reliable performance, certified ratings, and easy maintenance.