Thermocouple sensor is what?

Thermocouple is one of the most commonly used temperature detecting element in industry. Thermocouple sensor is what?

the fundamental laws of thermocouple sensor

1, the law of equivalent size and direction of the thermocouple thermoelectric potential by thermocouple material and decided to work end and free end temperature difference, and has nothing to do with other factors. Therefore, when the temperature of the working side and free side is equal, the thermoelectric potential is zero; When the thermocouple loop when insert the third wire material, as long as the third at the ends of the material temperature is equal, the size of the thermocouple circuit of thermoelectric potential and direction will not change.

2, score law, two end temperature of T1, T2 thermocouple thermoelectric potential is equal to the same temperature thermocouple at both ends for T1, T3 and T3 and T2 when the sum of two thermocouple thermoelectric potential, T3 for arbitrary temperature between T1 and T2.

3, superposition law when the thermocouple loop composed of a variety of wire material following multiple thermocouples, loop in thermoelectric power is equal to the nodes in the end, for work on both sides of the nodes in the wire for the thermocouple cold electrodes on the same side of thermoelectric potential and algebra.

4, exchange law when there are multiple thermocouples concatenated thermocouple loop, if the temperature at the ends of the thermocouple is equal, each thermocouple are interchangeable between the positive and the positive and negative and negative, loop total thermoelectric potential remains the same. Thermocouple sensor is of high precision, wide range of measuring temperature, but need to deal with the amplifier and the cold end.

the characteristics of the thermocouple sensor:

1, simple structure, easy fabrication, wide measuring range, simple structure, convenient manufacture, wide measuring range, high precision, small inertia, and output signal remote transmission and many other advantages.

2, thermocouple sensor is a kind of active sensors that measure does not need additional power supply, is a kind of active sensor, power source, use very convenient, is often used as measurement of gas stove, the pipe surface temperature or the temperature of the liquid and solid.

the working principle of thermocouple sensor:

thermocouple sensor is mainly according to the thermoelectric effect to work. Connect the two different conductor A and B, to form A closed loop, the original is A heat. When the conductor of A and B two contact when there is A temperature difference between 1 and 2 occurs between the electromotive force, thus forming A certain size of current in circuit, this kind of phenomenon called the thermoelectric effect, also called wen electric effect.

common types of thermocouple:

1) Platinum rhodium 10 - Platinum thermocouple index number is 5, the anode is made of 90% 10% of platinum and rhodium wire, negative extremely pure platinum wire.

2) Platinum rhodium 30 - Platinum rhodium thermocouple 6 index number is LL - Developed a kind of high temperature thermocouple is 60 s, is widely used in high temperature measurement.

3) Nickel chrome - Nickel silicon ( Or nickel chrome - Nickel aluminum) Thermocouple index number for EU - 2, the anode nickel chrome ingredients are: 0 ~ 10% chromium, 9. 4% silicon, the rest for nickel, nickel cathode silicon components in 2. 5 - 3% silicon, 0 or less. 6% cobalt, the rest for nickel.

4) Nickel chrome - Copper thermocouple number index in EA - test 2. 5) Copper - Its characteristic is high sensitivity, thermal electrode is easy to copy, the price is low, in the low temperature ( 0~100℃) Accuracy is higher, it can make second-class standard thermocouples.

related knowledge:

problems need attention when using thermocouple

the advantages and disadvantages of some commonly used thermocouple

how to correctly use the thermocouple temperature sensor from the architecture of the thermocouple to understand the working principle of thermocouple,

the most detailed thermocouple selection rules