Explosion-Proof Thermocouple

Explosion-proof thermocouple certified for hazardous areas, suitable for petrochemical, gas and mining environments where intrinsic safety is required.

Product Application

Usually used in conjunction with display instruments, recording instruments, electronic computers and so on. Direct measurement of various production processes (0 ~ 1300)°C range of liquid, steam and gas media and solid surface temperature.

Product Principle

According to the gap explosion-proof principle, explosion-proof thermocouples are designed with sufficient strength of the junction box and other components, all the parts that will produce sparks, arcs and dangerous temperatures are sealed in the junction box cavity. When an explosion occurs in the cavity, it can be quenched and cooled through the gap between the joint surfaces, so that the flame and temperature after the explosion can not be transmitted outside the cavity, thus providing explosion-proof.

Product Features

Suitable for a wide range of explosion-proof environments.
Spring compression type temperature sensing element, good vibration resistance.
Large measuring range.
High mechanical strength, good pressure resistance.

Technical Parameters

1. Executive Standard of the Product

National standard GB/T30429, GB/T3836.

2. Room Temperature Insulation Resistance

The insulation resistance of the Explosion-Proof Thermocouple is ≥ 1000 MΩ between the electrode and the outer casing at an ambient temperature of (20 ± 15)°C, a relative humidity of not more than 80%, and a test voltage of (500 ± 50)V DC.

3. Temperature measurement range and tolerance

Model	Graduation	Tolerance level
		I		II
		Tolerance value	Temperature range	Tolerance value	Temperature measurement range
WRNK	K	-40 ~ +375	±1.5°C	-40 ~ +333	±2.5°C
WRNK	K	375 ~ 1000	±0.004\|t\|	333 ~ 1200	±0.0075\|t\|
WRMK	N	-40 ~ +375	±1.5°C	-40 ~ +333	±2.5°C
WRMK	N	375 ~ 1000	±0.004\|t\|	333 ~ 1200	±0.0075\|t\|
WREK	E	-40 ~ +375	±1.5°C	-40 ~ +333	±2.5°C
WREK	E	375 ~ 800	±0.004\|t\|	333 ~ 900	±0.0075\|t\|
WRFK	J	-40 ~ +375	±1.5°C	-40 ~ +333	±2.5°C
WRFK	J	375 ~ 750	±0.004\|t\|	333 ~ 750	±0.0075\|t\|
WRCK	T	-40 ~ +125	±0.5°C	-40 ~ +133	±1.0°C
WRCK	T	125 ~ 350	±0.004\|t\|	133 ~ 350	±0.0075\|t\|
WRPK	S	0 ~ +1100	±1.0°C	0 ~ 600	±1.5°C
WRPK	S	1100 ~ 1600	±[1+0.003(t-1100)]	600 ~ 1600	±0.0025\|t\|
WRQK	R	0 ~ +1100	±1.0°C	0 ~ 600	±1.5°C
WRQK	R	1100 ~ 1600	±[1+0.003(t-1100)]	600 ~ 1600	±0.0025\|t\|
WRRK	B	/	/	600 ~ 1700	±0.0025\|t\|

4. Explosion proof grouping form

Prefix	Type of Protection	Equipment Group	Gas/Dust Grouping	Temperature group
	Ex	db: Explosion-proof	II: Class II electrical equipment	A, B, C	T1~T6
		ia: Intrinsically safe	II: Class II electrical equipment
tb: Dust type		III: Class III electrical equipment

5.Maximum surface temperature grouping of Class Il electrical equipment

Temperature grouping	Maximum surface temperature (°C)
T1	≤240
T2	≤300
T3	≤200
T4	≤135
T5	≤100
T6	≤85

6. Terminal box form

Protection level: IP65, IP66, IP68

Terminal box form

A type
B type
C type

7. List of certification information

Name	Maximum surface temperature (°C)	Certificate authority
Explosion proof thermocouple	Ex db IIC T4...T6 Gb / Ex tb IIIC T80°C...T130°C Db	NEPSI
Explosion proof thermocouple	Ex db IIB T4...T6 Gb, Ex tb IIIB T80°C...T130°C Db	NEPSI
Intrinsic safety thermocouple	Ex db IIC T4...T6 Gb, Ex ia IIIC T135°C/T200°C Da	NEPSI

Note: NEPSI Explosion-proof certification is a national instrumentation.

Model Naming Method

Temperature Instruments

Thermocouples

Temperature sensing element material

NNickel-chromium-nickel-silicon

ENickel-chromium-copper-chromium

MNickel-chromium-silicon-nickel-silicon

FIron-copper-nickel

CCopper-copper-nickel

PPlatinum-rhodium 10-platinum

QPlatinum-rhodium 13-platinum

RPlatinum-rhodium 30-platinum-rhodium 6

KArmored

-Assembly

Coupling wire pairs

2Double branch

-Single branch

Fixed installation

1No fixed installation

2Fixed thread

3Adjustable flange

4Fixed flange

6Flexible tube joint type

7Straight tube fitting type

8Fixed thread tube fitting type

9Adjustable thread tube fitting type

Terminal box type

4Explosion-proof

Protective tube diameter

0Φ16

1Φ20

2Φ2

3Φ3

4Φ4

5Φ5

6Φ6

8Φ8

-None

Sleeve form

-See attachment

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