WRNK-421 WRNK2-421 WRNK-422 WRNK2-422 Armored thermocouple

WRNK-421 WRNK2-421 WRNK-422 WRNK2-422 Armored thermocouple

Overview of WRNK-421 WRNK2-421 WRNK-422 WRNK2-422 Armored thermocouple

As a temperature measurement sensor, armored thermocouple is usually used together with temperature transmitter, regulator and display instrument to form a process control system to directly measure or control the temperature of fluid, steam, gas medium and solid surface in the range of 0-1800 ℃ in various production processes. Armor thermocouple has many advantages, such as bending, high pressure resistance, fast thermal response time and durability. Like industrial assembled thermocouple, it is usually used as a temperature sensor with display instrument, recording instrument and electronic regulator.

Working principle of WRNK-421 WRNK2-421 WRNK-422 WRNK2-422 Armored thermocouple

The structural principle of the armored thermocouple is that it is made of conductors, high-insulation magnesium oxide, and 1Cr18Ni9Ti stainless steel protection tube of the outer jacket, which are drawn together for many times. Armored thermocouple products are mainly composed of junction boxes, terminals and armored thermocouples, which are combined with various installation and fixtures.

The working principle of the armored thermocouple is that two conductors with different components are welded at both ends to form a loop. The direct temperature measurement end is called the working end, and the terminal end is called the cold end, also called the reference end. When there is a temperature difference between the working end and the reference end, a thermal current will be generated in the loop. When the display instrument is connected, the instrument will indicate the corresponding temperature value of the thermoelectromotive force generated by the thermocouple. The thermoelectromotive force of the armored thermocouple will increase with the increase of the temperature of the measuring end. The size of the thermoelectromotive force is only related to the material of the thermocouple conductor and the temperature difference between the two ends, and has nothing to do with the length and diameter of the thermode.

Features of WRNK-421 WRNK2-421 WRNK-422 WRNK2-422 Armored thermocouple

Armored thermocouple is the most widely used temperature device in temperature measurement. Its main features are that it has a wide range of kiss detection, relatively stable performance, simple structure, good dynamic response, and can transmit 4-20mA electrical signals far away. It is convenient for automatic control and centralized control. The principle of thermocouple temperature measurement is based on the thermoelectric effect. Two different conductors or semiconductors are connected into a closed loop. When the temperatures at the two junctions are different, a thermoelectric potential will be generated in the loop. This phenomenon is called the thermoelectric effect, also known as the Seebeck effect. The thermoelectric potential generated in a closed loop consists of two potentials; the thermoelectric potential and the contact potential. Thermoelectric potential refers to the potential generated by the temperature difference between the two ends of the same conductor. Different conductors have different electron densities, so they generate different potentials. The contact potential, as the name suggests, refers to the contact between two different conductors. Because their electron densities are different, a certain amount of electron diffusion occurs. When they reach a certain equilibrium, the potential formed by the contact potential depends on the material properties of the two different conductors and the temperature of their contact points.

Thermocouples used internationally have a standard specification, which stipulates that thermocouples are divided into eight different divisions, namely B, R, S, K, N, E, J and T, and the lowest measurable temperature of their measurement temperature. Minus 270 degrees Celsius, up to 1800 degrees Celsius, of which B, R, S belong to the platinum series of thermocouples, because platinum is a precious metal, so they are also called precious metal thermocouples and the rest are called cheap metal thermocouples . There are two types of thermocouple structures, common type and armored type. Ordinary thermocouples are generally composed of hot electrodes, insulating tubes, protective sleeves and junction boxes, while armored thermocouples are assembled by combining thermocouple wires, insulating materials and metal protective sleeves. A solid assembly formed by stretching. However, the electrical signal of the thermocouple needs a special wire to transmit, which we call the compensation wire.

Different thermocouples require different compensation wires, and their main function is to connect with the thermocouple to keep the reference end of the thermocouple away from the power supply, so as to stabilize the temperature of the reference end. The compensation wire is divided into two types: compensation type and extension type. The chemical composition of the extension wire is the same as that of the thermocouple being compensated. However, in practice, the extension wire is not made of the same material as the thermocouple. A wire with the same electron density is replaced. The connection between the compensation wire and the thermocouple is generally very clear. The positive pole of the thermocouple is connected to the red wire of the compensation wire, and the negative pole is connected to the remaining colors. Most of the general compensation wires are made of copper-nickel alloys.

Main tech data

Model:  WRNK-421 WRNK2-421 WRNK-422 WRNK2-422

Material for temperature-sensing element: Nickel chromium-nickel silicon

Numbers of thermal wire couple: Non, single support

2 double support

Installation and fixation mode: Fixed-sleeve flange

Junction box form:  water-proof type

Form in the working terminal: 1 Upper and lower limitation

2 Double upper limitations