Armoured thermocouple

Working principle: armoured thermocouple electrode is composed of two different conductor material.When measuring the terminal temperature difference is with the reference, the will be born thermoelectric potential, the instrument will show thermoelectric potential corresponding temperature value.
Thermocouple classification:
Commonly used thermocouple could be divided into two types: standard thermocouple and non-standard thermocouple:
Invokes standard thermocouple is refers to the national standard specifies its thermoelectric potential and the relationship between temperature, permissible error, and a unified standard score table of thermocouple, it has with matching display instrument to choose from.
Non-standard thermocouple or on the order of magnitude less than the range using standardized thermocouple, generally no unified indexing table, mainly used for the measurement of some special occasions.
Standardized thermocouple since January 1, 1988 in our country, the thermocouple and thermal resistance were manufactured according to IEC international standard, and specify the S, B, E, K, R, J, T seven standardization thermocouple type thermocouple for our country unified design.Thermocouple index number mainly S, R, B, N, K, E, J, T wait for a few kinds.S, R, B belong to precious metal thermocouple, N, K, E, J, T belong to cheap metal thermocouple.
The following is the interpretation of the thermocouple indexing number:
S 10 pure platinum rhodium platinum R platinum rhodium pure platinum 13 B 30 6 K platinum rhodium platinum rhodium pure copper nickel chromium nickel silicon T J iron copper nickel copper nickel N nickel chrome silicon ni si E nickel chromium copper nickel (S type thermocouple) 10 - platinum platinum-rhodium thermocouple 10 - platinum platinum-rhodium thermocouple
Thermocouple model (S) for the precious metal thermocouple.Accidentally silk regulation of 0.5 mm diameter, allowable deviation - 0.015 mm, the anode (SP) in the name of the chemical composition of platinum rhodium, contain the rhodium was 10%, including platinum was 90%, the cathode (SN) is a pure platinum, commonly known as single platinum-rhodium thermocouple.The thermocouple long-term maximum temperature of 1300 ℃, the highest short-term using temperature is 1600 ℃.S type thermocouple in the thermocouple series has the highest accuracy, stability, best to measure your area wide, long service life, etc.Its physical and chemical performance is good, the thermoelectric potential stability and oxidation resistance at high temperature performance is good, suitable for oxidizing and inert atmosphere.Because of S type thermocouple has excellent comprehensive performance, in line with the international use of S type thermocouple temperature scale, has for a long time as an international scale interpolation instruments, "ITS - 90" provisions will not be as an international scale in check instruments, but the international advisory committee (CCT) think S type thermocouple temperature still can be used to approximately achieve the international scale.S type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low sensitive to read, mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger.

(R type thermocouple) platinum rhodium 13 - platinum thermocouple platinum rhodium 13 - platinum thermocouple type thermocouple (R) is a precious metal thermocouple.Accidentally silk regulation of 0.5 mm diameter, allowable deviation - 0.015 mm, the positive (RP) in the name of the chemical composition of the platinum rhodium, contain the rhodium was 13%, including platinum was 87%, the cathode (RN) as the pure platinum, long-term maximum temperature of 1300 ℃, short-term maximum temperature of 1600 ℃.R type thermocouple in the thermocouple series has the highest accuracy, stability, best measure [area wide, long service life, etc.Its physical and chemical performance is good, the thermoelectric potential stability and oxidation resistance at high temperature is good, suitable for oxidizing and inert atmosphere.Due to the comprehensive performance of R type thermocouple and S type thermocouple, has been difficult to promote in our country, in addition to imported equipment on temperature measurement has been employed, the inner temperature is used rarely.Between 1967 and 1971, the British NPL, the United States and Canada NBS NRC three major research institute conducted a research cooperation, the result shows that the stability of the R type thermocouple and reproducibility is better than S type thermocouple are, our country has yet to conduct the research.R type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low sensitive to read, mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger.
(type B) thermocouple platinum rhodium 30 - platinum rhodium 6 30 - platinum rhodium thermocouple platinum-rhodium thermocouple (type B) thermocouple for precious metals thermocouple.Accidentally silk regulation of 0.5 mm diameter, allowable deviation - 0.015 mm, the anode (BP) in the name of the chemical composition of platinum rhodium, contain the rhodium was 30%, including platinum was 70%, the cathode (BN) is a platinum rhodium, rhodium for content 6%, therefore, commonly known as the dual platinum-rhodium thermocouple.The thermocouple long-term maximum temperature of 1600 ℃, the highest short-term using temperature is 1800 ℃.B type thermocouple in the thermocouple series has the highest accuracy, stability, best measure [area wide, long service life, high temperature limit, etc.Suitable for oxidation and inert atmosphere, can also be short term used in vacuum, but does not apply to reducing atmosphere or containing metal or nonmetal steam atmosphere.B type thermocouple is an obvious advantage don't need a compensation for the compensation conductor, because in the range of 0 ~ 50 ℃ and internal potential less than 3 mu V.B type thermocouple deficiency is thermoelectric potential, thermoelectric potential rate is small, low sensitive to read, mechanical strength under high temperature to drop, is sensitive to pollution, precious metal materials is expensive, and one-time investment is larger.

(type K thermocouple) nickel chrome - nickel silicon thermocouple nickel chrome - nickel silicon thermocouple dosage (type K thermocouple) is the largest budget metal thermocouple, its dosage is the sum total of other thermocouple.The anode (KP) in the name of the chemical composition is: Ni, Cr = 90:10, the cathode (KN) chemical composition as follows: in the name of the Ni: Si = 97:3, the temperature is - 200 ~ 1300 ℃.K type thermocouple has advantages of good linearity, thermoelectric emfs, high sensitivity, good stability and uniformity, the oxidation resistance is strong, the advantages of cheap, can be used for oxidizing inert atmosphere.Widely adopted for the user.K type thermocouple cannot directly at high temperature for sulfur, reducing or reduction, oxidation atmosphere and vacuum alternately, also not recommended for people with weak oxidizing atmosphere.
(N type thermocouple) silicon nickel chrome - nickel silicon thermocouple nickel chrome - nickel silicon thermocouple (N type thermocouple) for inexpensive metal thermocouple, thermocouple is a kind of new international standardization, is successfully developed by the Australian defence laboratory, in the early 70 s it overcome the K type thermocouple two important faults: K type thermocouple between 300 ~ 500 ℃ due to the lattice short-range order of nickel-chromium alloy thermoelectric emfs caused by unstable;At about 800 ℃ caused by nickel chrome preferential oxidation thermoelectric emfs instability.The anode (NP) as follows: in the name of the chemical composition Ni, Cr, Si = 84.4:14.2:1.4, the cathode (NN) for the name of the chemical composition, Ni, Si, Mg = 95.5:4.4, 0.1, its temperature is - 200 ~ 1300 ℃.N type thermocouple has advantages of good linearity, thermoelectric emfs, high sensitivity, good stability and uniformity, oxidation resistance is strong, cheap, is not affected by short-range ordering etc, and its comprehensive performance is better than that of K type thermocouple, thermocouple is a kind of very promising. N type thermocouple cannot directly at high temperature for sulfur, reducing or reduction, oxidation atmosphere and vacuum alternately, is not recommended for people with weak oxidizing atmosphere.
(E type thermocouple) thermocouple nickel chromium copper nickel chrome - nickel - copper and nickel thermocouple type thermocouple (E) is also called the nickel chrome - constantan thermocouple, is also a kind of cheap metal thermocouple, the anode (EP) as follows: nickel chromium alloy 10, chemical composition is the same as the KP, copper and nickel alloy anode (EN), nominal chemical composition of: 55% copper, 45% nickel and a small amount of manganese, cobalt, iron and other elements.The use of the thermocouple temperature is 200 ~ 900 ���.E type thermocouple thermoelectric emfs, high sensitivity of all thermocouples, most appropriate made thermopile, measuring the temperature of the small change.Not very sensitive to high humidity atmosphere corrosion, appropriate is used in the environment of high humidity.E thermocouple has good stability and oxidation resistance is better than that of copper - constantan, iron - constantan thermocouple, the advantages of cheap, can be used for oxidizing and inert atmosphere, is widely used for the user.E type thermocouple cannot directly at high temperature for sulfur, reducing atmosphere, the uniformity of the thermoelectric potential is poorer.
(J type thermocouple) iron - copper nickel thermocouple iron - copper nickel thermocouple (J type thermocouple) is also called the iron - constantan thermocouple, is also a kind of cheap cheap metal thermocouple.Its positive electrode (JP) in the name of the chemical composition of pure iron, copper and nickel alloy anode (Jacqueline Nottingham), are often vaguely call constantan, its nominal chemical composition of: 55% copper and 45% nickel as well as small amounts of very important manganese, cobalt, iron and other elements, although it's called constantan, but different from that of nickel and chromium - constantan and copper-constantan constantan, so can't use EN and TN to replace.Iron - constantan thermocouple measuring temperature area is - 200 ~ 200 ℃, but usually use temperature range of 0 ~ 750 ℃.J type thermocouple has advantages of good linearity, thermoelectric emfs, high sensitivity, good stability and uniformity, the advantages of cheap, widely used by users.J type thermocouple can be used in the vacuum, oxidation, reduction and inert atmosphere, but iron anode oxidation at high temperature quickly, so the temperature is restricted, cannot be directly without reserve for curing atmosphere at high temperature.
(T thermocouple) copper, copper nickel thermocouple copper nickel - copper thermocouple (T thermocouple) is also called copper-constantan thermocouple, is also a kind of optimal measuring thermocouple of cheap metal at low temperature.It is the positive (TP) of the pure copper, copper and nickel alloy anode (TN), often a constantan, it with nickel chromium - constantan constantan EN general, and iron - constantan constantan Jacqueline Nottingham not general, although they are called constantan, copper, copper nickel the lid of the thermocouple temperature range of measurement is - 200 ~ 350 ℃.T thermocouple has advantages of good linearity, thermoelectric emfs is larger, higher sensitivity, stability and uniformity is good, the advantages of cheap, special - 200 ~ 0 ℃ temperature in the area to use, better stability and stability can be less than + / - 3 mu V, the low temperature test can be used as second class standard value transmit.in at low temperature.T thermocouple of the anode copper poor oxidation resistance at high temperature, so the temperature limit is restricted.