WZP-240 fixed thread explosion-proof thermal resistor
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Working principle
The structure and principle of explosion-proof thermistor and assembled thermistor are basically the same. The difference is that the junction box (shell) of explosion-proof products adopts a special explosion-proof structure in the design. The junction box is made of high-strength aluminum alloy die-casting and has sufficient internal space, wall thickness and mechanical strength. The thermal stability of the rubber sealing ring meets the national explosion-proof standards. Therefore, when the explosive mixed gas inside the junction box explodes, its internal pressure will not damage the junction box, and the resulting heat energy cannot diffuse or transmit to the outside.
Due to the use of the above-mentioned explosion-proof special structure, the product fully complies with the explosion-proof temperature range of dIIBT4 or dIICT6. As long as users strictly follow the product usage rules, the product can achieve reliable explosion-proof effect.
Main technical indicators
★ Temperature measurement range and allowable error
model | Graduation | measuring range | accuracy class | Allowable deviation △ t ℃ |
WZP WZP2 WZPK WZPK2 |
Pt100 | -200~500 | A-level | ±<650℃ ±(0.15+0.002∣t∣) |
Grade B | -Allowable deviation at 200-800 ℃ ± (0.30+0.005 ∣ t ∣) |
Note: "t" represents the absolute value of the measured temperature of the temperature sensing element, and the dual platinum resistance is only supplied to Class B.
Grade A is a special order
★ Nominal pressure
Generally refers to the static external pressure that the protective tube can withstand without breaking at room temperature, and the test pressure is generally 1.5 times the nominal pressure. In fact, the allowable nominal pressure is not only related to the material, diameter, and wall thickness of the protective tube, but also to its structural form, installation method, insertion depth, as well as the flow rate and type of the measured medium.
★ Thermal resistance insulation resistance
The test voltage for insulation resistance at room temperature can take any value from 10 to 100V DC, and the ambient temperature should be within the range of 15 to 35 ℃, with a relative temperature not exceeding 80%. The insulation resistance value at room temperature should not be less than 100M Ω.
★ Thermal resistance allows current to pass through
The maximum current measured through a platinum resistor shall not exceed 5mA
★ Explosion proof type and level group
Explosion proof level group: dIIBT4 or dIICT4; DIIBT6 or dIICT6
Shell protection level: IP54
Explosion proof Marking Method for Explosion proof Thermistors
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★ Explosion proof rating
The explosion-proof rating of explosion-proof thermal resistors is divided into three levels: A, B, and C, based on their maximum safe clearance for explosive gas mixtures.
★ Temperature group
The temperature groups of explosion-proof thermal resistors are divided into six groups, T1 to T6, based on the highest surface temperature of their exposed parts.
Temperature group | Maximum allowable surface temperature ℃ |
T1 | 450 |
T2 | 300 |
T3 | 200 |
T4 | 135 |
T5 | 100 |
T6 | 85 |
Please refer to the example table of explosion-proof thermocouples for the combustible gas, vapor level, and temperature group of explosion-proof platinum resistors.
Product selection
Explosion proof thermistor
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Explosion proof armored thermistor
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Types and specifications of explosion-proof thermal resistors
type | model | Graduation | Temperature measurement range ℃ | Protective tube material | thermal response time τ0.5S |
Nominal pressure MPa | structure characteristics | specifications | Explosion proof grade | |
Total length L | Insertion depth/mm | |||||||||
Platinum thermistor | WZP-24SA | Pt10 Pt100 |
-200~500 | 1Cr18Ni9Ti stainless steel perhaps 0Cr18Ni 12Mo2Ti |
≤90 | 10 | explosion - proof connection box Fixed thread installation M27×2 |
300 350 400 450 550 650 900 1150 |
150 200 250 300 400 500 750 1000 |
d Ⅱ BT4 d Ⅱ BT6 perhaps d Ⅱ CT4 d Ⅱ CT6 |
WZP2-24SA | ||||||||||
WZP-44SA | ||||||||||
WZP2-44SA | 6.4 | explosion - proof connection box Fixed flange installation |
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WZP-64S WZP2-64S |
1Cr18Ni9Ti | 30 | Cone shaped protective tube M33×2 |
100 200 300 |
Types and specifications of explosion-proof armored thermal resistors
Explosion proof armored thermistor
type | model | Graduation | Temperature measurement range ℃ | Protective tube diameter D | thermal response time τ0.5S |
Nominal pressure MPa | structure characteristics | specifications | Explosion proof grade | |
Total length L | Insertion depth/mm | |||||||||
Platinum thermistor | WZPK-24 WZPK2-24 |
Pt10 Pt100 |
-200~+500 | Φ6 perhaps Φ5 |
≤12 ≤8 |
10 | explosion - proof connection box Fixed thread installation M27×2 |
150 200 300 400 500 750 1000 |
d Ⅱ BT4 d Ⅱ BT6 perhaps d Ⅱ CT4 d Ⅱ CT6 |
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WZPK-44 WZPK2-44 |
6.4 | explosion - proof connection box Fixed flange installation |
Install fixed devices
Installation of fixed devices can be divided into three forms: fixed threads, tapered fixed threads, and fixed flanges. The structural dimensions are shown in the table.
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Protective tube diameter D | M | h | S | D0 | Flow velocity m/s | Maximum operating pressure (MPa) | |
Φ12 Φ16 |
M27×2 | 32 | 32 | Φ40 | 10 | |||
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M33×2 | 33 | 36 | Φ48 | 80 | 30 | ||
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Φ12 Φ16 |
D2 | D1 | D0 | d0 | H | h | 6.4 |
Φ95 | Φ65 | Φ45 | Φ14 | Φ14 | 2 |
Applicable medium for explosion-proof thermistor
★ Explosion proof level and temperature group of flammable gases and vapors:
order | Explosion proof grade IIA | Explosion proof grade IIB | ||
Media name | Temperature group | Media name | Temperature group | |
1 | Methane, ethane, propane, kinetic benzene | T1 | propyne | T1 |
2 | Benzene, toluene, xylene, trimethylbenzene | cyclopropene | ||
3 | Phenol, cresol, bisketol | hydrogen cyanide | ||
4 | Acetone, butanone, pentanone, diketone | hydrogen | ||
5 | Acetic acid, methyl acetate, chloroethane, bromoethane | Acrylic | ||
6 | Chloroethylene, dichloroethylene, trichlorotoluene | coke oven gas | ||
7 | Dichloromethane, dichloropropane, chlorobenzene, ammonia | water gas | ||
8 | Carbon monoxide, benzyl chloride, dichlorobenzene | ethylene | T2 | |
9 | Toluene, triethylamine, pyridine | butadiene | ||
10 | Ethyl acetate | Epoxypropane | ||
11 | Styrene, methyl styrene, naphthalene | Dioxane | ||
12 | Butane, cyclopentane, methylcyclopentane | T2 | Trioxane | |
13 | Isopropyl benzene, methyl, methanol to butanol | methyl acrylate | ||
14 | Methyl methacrylate, ethyl acetyl acetate | ethyl acrylate | ||
15 | N-propylamine, n-butylamine, aniline, NN dimethylaniline | furan | ||
16 | Methyl formate, ethyl formate | dimethyl ether | T3 | |
17 | Dichloroethane, allyl chloride, chloroethanol, thiophene | tetrahydrofurfuryl alcohol | ||
18 | Methylamine, dimethylamine, diethylamine | hydrogen sulfide | ||
19 | Acetylacetone, cycloethanol, nitromethane, nitroethane | acrolein | ||
20 | Acrylic, ethylbenzene, methyl acetate to pentyl acetate | T3 | Crotonaldehyde | |
21 | Methyl cyclohexane, turpentine, naphtha | Tetrahydrofuran | ||
22 | Pentane to decane, cyclohexane, naphthalene, cyclohexylamine | ethyl methyl ether | T4 | |
23 | Ethyl cyclohexane, ethyl cyclohexane, ethyl cyclopentane | diethyl ether | ||
24 | Petroleum, gasoline, diesel, kerosene, coal tar | dibutyl ether | ||
25 | Pentanol, hexanol, cyclohexanol, methyl cyclohexanol | ethylene oxide | ||
26 | Chloropropane, chlorobutane, bromobutane | Tetrafluoroethylene | ||
27 | Acetyl chloride, ethyl mercaptan, tetrahydrothiophene | carbon disulfide | T5 | |
28 | Acetaldehyde, trimethylamine | T4 | Ethyl nitrate | T6 |
Product selection
Explosion proof thermistor
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Explosion proof armored thermistor
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