The integration of explosion-proof heat resistance
A. Product introduction
Usually the integration of explosion-proof resistance and display instrument, recording instrument, such as the electronic computer, 4 ~ 20 ma output.Direct measurement within the scope of the 0 ~ 1800 ℃ in the process of producing all kinds of liquid, steam and gas medium, as well as solid surface temperature.
2. Product main features
Two wire output 4 ~ 20 ma, strong anti-interference ability;
Save the compensation conductor and temperature transmitter installation cost;
Measuring range is large;
The cold end temperature automatic compensation, nonlinear correction circuit.
3. Working principle
Integration of explosion-proof heat resistance by using the theory of flame-proof clearance, when an explosion cavity, can remove from heat and cooling by joint clearance, make after the explosion flame temperature less than outside the cavity, thereby for temperature measurement.Thermocouple (resistance) production of thermoelectric potential (resistance) after temperature transmitter of bridge produce unbalance signal, after amplification into 4 ~ 20 ma dc signal to the instrument, the instrument will show the corresponding temperature value.
4. Technical parameters
Execution standard
IEC584 IEC1515 IEC751 JB/T5518-91 JB/T7391-94
5. The temperature measurement range and tolerance (thermocouple)
model | Degree, | Allowed error and accidentally material level | |||
Class I | Class II | ||||
Tolerance values | ℃ temperature range | Tolerance values | ℃ temperature range | ||
WRNB | K | Plus or minus 1.5 ℃ | - 40 ~ + 375 | Plus or minus 2.5 ℃ | - 40 ~ + 333 |
±0.004│t│ | 375 ~ 1000 | ±0.0075│t│ | 333 ~ 1200 | ||
WRMB | N | Plus or minus 1.5 ℃ | - 40 ~ + 375 | Plus or minus 2.5 ℃ | - 40 ~ + 333 |
±0.004│t│ | 375 ~ 1000 | ±0.0075│t│ | 333 ~ 1200 | ||
WREB | E | Plus or minus 1.5 ℃ | - 40 ~ + 375 | Plus or minus 1.5 ℃ | - 40 ~ + 333 |
±0.004│t│ | 375 ~ 800 | ±0.004│t│ | 333 ~ 900 | ||
WRFB | J | Plus or minus 1.5 ℃ | - 40 ~ + 375 | Plus or minus 1.5 ℃ | - 40 ~ + 333 |
±0.004│t│ | 375 ~ 750 | ±0.004│t│ | 333 ~ 750 | ||
WRCB | T | Plus or minus 1.5 ℃ | - 40 - ~ + 125 | + / - 1 ℃ | - 40 ~ + 333 |
±0.004│t│ | 125 ~ 350 | ±0.0075│t│ | 133 ~ 350 | ||
WRPB | S | + / - 1 ℃ | 0 ~ + 1100 | Plus or minus 2.5 ℃ | 0 ~ 600 |
±[1+0.003(t-1100)] | 1100 ~ 1600 | ±0.0025│t│ | 600 ~ 1600 |
Note: thermal components measured temperature t absolute value.
Temperature measurement range and tolerance (heat resistance)
model | Degree, | ℃ temperature range | Precision grade | Allowable deviation |
WZPB | Pt100 | - 200 ~ + 500 | A grade | ±(0.15+0.002|t|) |
Class B | ±(0.30+0.005|t|) | |||
WZCB | Cu50 | - 50 ~ + 100 | - | ±(0.30+0.006|t|) |
Cu100 |
Note: thermal components measured temperature t absolute value.
Explosion-proof level:
Flame-proof type: dIIBT4, dIICT5 dIICT6
Intrinsically safe type: iaIICT6
6. Other parameters
Output signals: 4 ~ 20 ma, 250 Ω load resistance, 100 Ω transmission conductor resistance
Output method: two wire
Tolerance level: 0.1;0.2;0.5
Power supply: 24 v DC + / - 10%
Protection grade: IP65
Thermal response time
When the temperature appear step change, the instrument of current output signal changes to correspond to the step change of 50% of the time required, usually expressed as a tau 0.5 when temperature transmitter does not exceed the stable step response time of thermocouple (resistance) of stable thermal response time tau 0.5 five points, with a thermocouple (resistance) thermal response time as the instrument of thermal response time;
When the temperature transmitter does not exceed the stable step response time of thermocouple (resistance) 0.5 half of the stable thermal response time tau, the temperature transmitter thermal response time is used as the instrument of the thermal response time.