B-type platinum rhodium wire platinum rhodium thermocouple

Industrial assembled thermocouples are commonly used as temperature sensors in conjunction with display instruments, recording instruments, and electronic regulators. It can directly measure the surface temperature of liquids, vapors, gases, and solids within the range of 0 ℃ to 1800 ℃ in various production processes.

Main technical indicators:

Temperature measurement range and allowable error

Thermal response time:

When there is a step change in temperature, the output of the thermocouple changes to 50% of the change, and the time required is called the thermal response time, represented by T0.5.

Thermocouple nominal pressure:

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 and diameter 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.

Minimum insertion depth of thermocouple:

It should not be less than 8-10 times the outer diameter of its protective tube (except for special products).

Thermocouple insulation resistance (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 of 15-35 ℃, relative humidity of 45%, and atmospheric pressure of 86-106kPa.

a. For thermocouples with a length exceeding 1 meter, the product of their insulation resistance at room temperature and their length should not be less than 100

即Rr. L≥100 MΩ。 M L＞1m

In the formula, the insulation resistance value of Rr thermocouple at room temperature is M Ω

b. For thermocouples with a length of 1 meter or less, their insulation resistance at room temperature should not be less than 100 M Ω

Upper limit temperature insulation resistance

The insulation resistance of the upper limit temperature of the thermocouple should not be less than the following specifications:

□ Model representation:

Working principle:

The working principle of a thermocouple is that two conductors with different compositions are welded at both ends to form a circuit. The temperature measuring end is called the measuring end, and the wiring terminal end is called the reference end. When there is a temperature difference between the measuring end and the reference end, a thermal current will be generated in the circuit. When connected to a display instrument, the instrument will indicate the corresponding temperature value of the thermoelectric potential generated by the thermocouple.

The thermoelectric potential of a thermocouple will increase as the temperature at the measuring end rises. The magnitude of the thermoelectric potential is only related to the material of the thermocouple conductor and the temperature difference between the two ends, and is independent of the length and diameter of the thermoelectric electrode.

Prefabricated thermocouples are mainly composed of a junction box, protective tube, insulating sleeve, terminal block, and thermoelectric electrode, and are equipped with various installation and fixing devices.

□ Model and specification:

Unified design thermocouple

Non fixed device type (ceramic protective tube) thermocouple

Note: 1) Structural features: The non embedded part is made of carbon steel 20 #

2) A double-layer ceramic sleeve with a diameter of 25mm.

3) Special specifications are ordered with large "*" division marks.

Specification table for diameter and length of protective tube:

Non fixed device thermocouple:

Note 1) Thermal response time T0.5<90 seconds

2) The symbol "#" in the protective tube material indicates that there is no material of this grade for double support

3) Use the "*" division mark for special specification ordering