| Explosion-proof thermal resistorDetailed information: |
■ Features of Explosion-Proof Resistance Temperature Detectors
●Tension spring type temperature sensing element, excellent vibration resistance.
Wide measurement range;
● No compensation wire needed, saving costs;
● Imported thin-film resistor elements, reliable and stable performance.
■ Explosion-proof thermistor working principle
Explosion-proof thermistors utilize the gap-type explosion suppression principle. They are designed with components such as junction boxes that have sufficient strength. All parts that can generate sparks, arcs, or dangerous temperatures are sealed within the junction box cavity. In the event of an explosion inside the cavity, the fire can be extinguished and cooled through the gaps at the mating surfaces, preventing the flame and temperature from spreading outside the cavity, thereby enabling temperature measurement.
■ Main Technical Parameters of Explosion-proof Resistance Temperature Detectors
Product Execution Standard
IEC751
JB/T8622-1997
JB/T9623-1997
JB/T5518-91
Explosion-proof thermistor ambient temperature insulation resistance
Explosion-proof thermistors, operating within an environmental temperature range of 15~35°C, with a relative humidity not exceeding 80%, and tested at a voltage of 10~100V (DC), the insulation resistance between the electrode and the sheath tube is ≥100MΩ.m.
■ Temperature Measurement Range and Tolerance
● Temperature Measurement Range and Tolerance
Model | Pitch number | Measurement Range | Precision Grade | Permitted Deviation |
LRD- WAPJ | Pt100 | -200~ +500 | Grade A | ±(0.15+0.002|t|) |
Grade B | ±(0.30+0.005|t|) | |||
LRD-WZCJ | Cu50 | -50~+100 | - | ±(0.30+0.006|t|) |
Note: "t" represents the absolute temperature value of the actual temperature measurement of the thermosensitive element.
● Evidence Inventory Sheet
| Explosion-proof rating | Ex-proof Certificate Number | Certification Authority |
| dIIB T4 | GYB96451 | NEPSI |
| dIIB T4 | GYB96452 | NEPSI |
| dII CT5 | GYB98338 | NEPSI |
| dII CT5 | GYB97198 | NEPSI |
| iaIICT6 | GYB99413 | NEPSI |
Note: NEPSI explosion-proof certification is provided by the National Explosion-Proof Supervision and Inspection Station for Instruments and Meters.
● Explosion-proof grouping form

Electrical Equipment Categories
Class I - Electrical Equipment for Coal Mine Underground Use
Class II - Industrial Electrical Equipment
○ Explosion-proof grade
Intrinsically Safe Thermocouples have explosion-proof grades divided into three levels: A, B, and C, based on their maximum safe gap for use in explosive gas mixtures.
| Category | Level | Maximum Experimental Safety Gap (MESG) mm |
| II | A | 0.9≤MESG |
| B | 0.5<MESG<0.9 | |
| C | MESG≤0.5 |
○Temperature Category
The temperature classes of explosion-proof thermocouples are divided into T1 to T6 based on the maximum allowable surface temperature of their exposed parts.
| Temperature Group | Maximum surface temperature allowed: °C |
| T1 | 450 |
| T2 | 300 |
| T3 | 200 |
| T4 | 135 |
| T5 | 100 |
| T6 | 85 |
● Explosion-proof grade
●EXd II□T□
●Exia II□T□
● Protection Level: IP65
■ Junction box style
● dⅡBT□ level ● dⅡCT□ level
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■ Terminal Installation Type
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■Model Naming Method
LRD-W | Thermometer gauge | |||||||
| | Z | Resistance Temperature Detector (RTD) | ||||||
| | Thermally sensitive material | |||||||
P | Platinum Pt | |||||||
| | Even Count Yarn | |||||||
No content provided. | Single Piece | |||||||
| | Installation Mount | |||||||
1 | Unfixed installation | |||||||
| | Connector box style | |||||||
4 | Explosion-proof | |||||||
| | Pipe protection diameter | |||||||
0 | Φ16 | |||||||
| | Work end form | |||||||
G | Variable cross-section | |||||||
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LRD- W | Z | P | 2 - | 2 | 4 | 0 | G | Typical Model Examples |
Selection Guidelines
Model
2) Tolerance grade
3) Explosion-proof rating
4) Precision Grade
5) Installation and Mounting Type
6) Pipe Protection Material
7) Length or Insertion Depth
Ex. A: Explosion-proof thermistor, Pt100 type, fixed thread M27×2, explosion-proof grade dⅡBT4, protective tube 316, insertion depth 300mm. ZK-WZP-240, Pt100, L=450×300, dⅡBT4 temperature transmitter 0.5 class, protective tube 316, thread M27×2.

































