WRN-430 Prefabricated Thermocouple

Product Details:

Introduction:

Industrial prefabricated thermocouples, as temperature sensors, are usually used in conjunction with display instruments, recording instruments, and electronic regulators. They can directly measure the surface temperature of liquids, steam, gas media, and solids in various production processes ranging from 0℃ to 1800℃.

According to national regulations, our factory has been producing thermocouples that comply with IEC international standard graduation numbers since 1987, including platinum-rhodium₃₀-platinum-rhodium₆, platinum-rhodium₁₀-platinum, nickel-chromium-nickel-silicon, nickel-chromium-copper-nickel, copper-copper-nickel, iron-copper-nickel, etc., which should comply with the JB/T3238-1999 standard.

Working Principle: The working principle of a thermocouple is: two conductors of different compositions are welded at both ends to form a loop. The direct temperature measurement end is called the measuring end, and the terminal end is called the reference end. When there is a temperature difference between the measuring end and the reference end, a thermal current is generated in the loop. When connected to a display instrument, the instrument indicates the corresponding temperature value of the thermoelectric electromotive force generated by the thermocouple.

The thermoelectric electromotive force of the thermocouple increases with the temperature rise of the measuring end. The magnitude of the thermoelectric electromotive force is only related to the material of the thermocouple conductors and the temperature difference between the two ends, and is independent of the length and diameter of the thermoelectrode.

The prefabricated thermocouple mainly consists of a junction box, protective tube, insulation tube, terminal block, and thermoelectrode as the basic structure, and is equipped with various installation and fixing devices.

Temperature Measurement Range and Allowable Error

Thermocouple Type	Code	Graduation Number	Measurement Range ℃	Allowable Deviation △t ℃
Platinum-Rhodium₃₀-Platinum-Rhodium₆	WRR	B	0～800	±1.5℃ or ±0.25%│t│
Platinum-Rhodium10-Platinum	WRP	S	0～1600	±1.5℃ or ±0.25%│t│
Nickel-Chromium-Nickel-Silicon	WRN	K	0～1300	±2.5℃ or ±0.75%│t│
Nickel-Chromium-Copper-Nickel	WRE	E	0～800	±2.5℃ or ±0.75%│t│

Note: "t" is the actual temperature measured by the temperature sensing element

Thermal Response Time

When the temperature undergoes a step change, the time required for the thermocouple output to change to 50% of the corresponding change is called the thermal response time, expressed as T_0.5.

Nominal Pressure of Thermocouple

Generally refers to the static external pressure that the protective tube can withstand at room temperature without breaking. In fact, the allowable working 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, and the flow rate and type of the measured medium.

Minimum Insertion Depth of Thermocouple

Should be no less than 8 to 10 times the outer diameter of its protective tube (except for special products).

Insulation Resistance of Thermocouple (at Room Temperature)

The test voltage for room temperature insulation resistance is DC 500V ± 50V. The atmospheric conditions for measuring room temperature insulation resistance are temperature 15～35℃, relative humidity 45%, and atmospheric pressure 86～106kPa.

a. For thermocouples longer than 1 meter, the product of their room temperature insulation resistance value and their length should be no less than 100.

i.e., Rr·L ≥ 100 MΩ·M, L > 1m

Where: Rr - Room temperature insulation resistance value of the thermocouple in MΩ

b. For thermocouples with a length equal to or less than 1 meter, their room temperature insulation resistance value should be no less than 100 MΩ.