WRN-430 Assembly Thermocouple

Product Details:

Introduction:

Industrial assembly 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°C to 1800°C.

According to national regulations, our factory has been producing thermocouples conforming to IEC international standard graduation 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 comply with 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 temperature value corresponding to the thermoelectric electromotive force generated by the thermocouple.

The thermoelectric electromotive force of a thermocouple increases with the temperature of the measuring end. The magnitude of the thermoelectric electromotive force depends only on the material of the thermocouple conductors and the temperature difference between the two ends, and is independent of the length and diameter of the thermoelectrodes.

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

Temperature Measurement Range and Allowable Error

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

Note: "t" is the actual temperature of 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, denoted by T_0.5.

Nominal Pressure of Thermocouple

Generally refers to the static external pressure that the protection tube can withstand at room temperature without rupture. In practice, the allowable working pressure depends not only on the material, diameter, and wall thickness of the protection tube but also on 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 protection 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°C, relative humidity 45%, and atmospheric pressure 86～106 kPa.

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

i.e., Rr·L ≥ 100 MΩ·M, L > 1m

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

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