The WZ series industrial thermistor is commonly used as a temperature measurement sensor, which is usually paired with temperature transmitters, regulators, and display instruments to form a process control system. It is used to directly measure or control the temperature of liquid vapor, gas media, and solid surfaces within the range of -200 ℃ -500 ℃ in various production processes.
Thermistor measures temperature by utilizing the characteristic that the resistance of a substance changes with temperature. When there is a temperature gradient in the medium, the measured temperature is the average temperature in the medium layer within the range of the temperature sensing element.
Although there are significant differences in the appearance of various thermal resistors, their basic structures are generally similar, consisting mainly of temperature sensing elements, insulation sleeves, protective tubes, and junction boxes.
Main technical characteristics
Measurement range and basic error limit

Thermal resistance category, model, division number, temperature measurement range, basic error limit
铂热电阻 WZP Pt10,Pt100 -200℃- +500℃ ±(0.3+0.0051t1)
铜热电阻 WZC Cu10,Cu100 -50℃- +100℃ ±(0.3+6.0×10-3t)

Note: t is the measured temperature value of the temperature sensing element
Permissible current: The measured current through the thermistor should not exceed 5 milliamps.
Thermal resistance time constant

Thermal inertia level time constant (seconds) Thermal inertia level time constant (seconds)
Ⅰ
90－180 Ⅲ
10-30
Ⅱ
30－90 Ⅳ
10

The nominal pressure of a thermal resistor generally refers to the static external pressure that the protective tube can withstand at operating temperature without breaking.
Thermal resistance * small insertion depth: should not be less than 8-10 times the outer diameter of its protective sleeve.
Insulation resistance: When the ambient air temperature is 15-35 ℃ and the relative humidity is less than 80%, the insulation resistance is ≥ 20 megohms (voltage 100V). The insulation resistance of the splash proof junction box should be 2 megohms (voltage 100V)
The resistance value (R0) of the thermistor temperature sensing element at 0 ℃ and its ratio to the resistance value (R100) at 100 ℃:
Ratio=R100/R
When the division marks are Pt10 and Pt100; R100/R0=1.3850±0.001
When the division marks are Cu50 and Cu100; R100/R0=1.3850±0.002

Model naming convention

Installation and use of thermal resistors
Thermal resistors should be avoided from being installed near the furnace or too close to the heating element. They should be installed in areas with minimal or no vibration, and should be easy to construct and maintain. The installation position should be kept as vertical as possible, but it must be installed at an angle when there is a flow rate. The outlet of the junction box should face downwards.
Thermal resistors should be wired according to regulations, generally using a three wire system. The connecting wire should use insulated (* * * * is screen open) copper wire, with a cross-sectional area of ≥ 1.0 square millimeter, and the resistance value of the wire should be registered according to the specifications of the display instrument.
To eliminate the error caused by the hysteresis of temperature changes in thermal resistance due to thermal inertia, the outer diameter of the thermal resistance protection tube should be minimized as much as possible, and the insertion depth of the thermal resistance should be appropriately increased to increase the number of heated parts of the thermal resistance.
Regularly check the condition of the protective tube, take immediate measures if oxidation or deformation is found, and conduct regular calibration.
Ordering Instructions
When placing an order, the user should specify: (1) Product name, (2) Product model, (3) Index number, (4) Material and diameter of protective tube, (5) Length L and insertion depth, (6) Quantity, (7) Fixed thread, (8) Special technical requirements.