Overview |
| Armored thermocouples offer many advantages such as bendability, high pressure resistance, fast thermal response time and ruggedness. They are used as temperature-measuring transmitters, as well as display instruments, recording instruments and electronic adjustments, just like industrial fabricated thermocouples. It can be used as a temperature sensor for assembled thermocouples. It can directly measure the temperature of liquid, vapor and gaseous media and solid surfaces from 0 to 800 °C in the production process. |
principle |
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| The working principle of the armored thermocouple is that the two ends of the conductors of different components are welded to form a loop, the direct temperature measuring 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 is generated in the circuit, and the display meter is connected, and the corresponding temperature value of the thermoelectromotive force generated by the thermocouple is indicated on the meter. |
| The thermoelectromotive force of the armored thermocouple will increase with the temperature of the measuring end. The magnitude of the thermoelectromotive force is only related to the thermocouple conductor material and the temperature difference between the two ends, and has nothing to do with the length and diameter of the hot electrode. |
| The structural principle of the armored thermocouple is that it is made of conductor, high-insulation magnesia, and jacket 1Cr18Ni9Ti stainless steel protection tube. Armored thermocouple products are mainly composed of junction boxes, terminal blocks and armored thermocouples, and are equipped with various mounting fixtures. |
Armored thermocouples are available in both insulated and shelled versions. |
Basic technical indicators |
category
(code number) | Graduation | Outer diameter of casing（ d） | Common temperature（℃） | Maximum operating temperature（℃） | Allowable deviation△ t | Measuring range（℃） | Allowable margin | Nickel-chromium-constantan
WREK | E | ≥φ 3 | 600 | 700 | 0～700 | ± 2.5℃or
± 0.75%t | Nickel Chromium-Nickel Silicon
WRNK | K | ≥φ 3 | 800 | 950 | 0～900 | ± 2.5℃or
± 0.75%t | Copper-Kang Copper
WRCK | T | ≥φ 3 | 350 | 400 | <-200 | No provision | -40～350 | ± 1℃或
± 0.75%t |
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Note: 1, t is the absolute value of the measured temperature 2, T-type index number products need to negotiate with the factory to order |
Armored thermocouple thermal response time |
| In the case of a step change in temperature, the time at which the output of the thermocouple changes to 50% of the step change is called the thermal response time, expressed as τ0.5. |
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Insulation resistance |
When the ambient air temperature is 20±1.5°C and the relative humidity is not more than 80%, the insulation resistance between the wire and the outer casing of the insulated armored thermocouple shall comply with the following table. |
Even wire diameter （ mm） | Test voltage （ V-DC） | Insulation resistance （ MΩ.m ） | 1.5 | 50±10% | ≥ 1000 | >1.5 | 500±10% | ≥ 1000 |
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Flexibility |
| The flexible radius of the armored thermocouple is not less than 5 times its outer diameter. |
Armored thermocouple thermal response time |
Thermal response time τ 0.5 second casing diameter (mm) | Shell type | Insulated | 3.0 | 0.6 | 1.2 | 4.0 | 0.8 | 2.5 | 5.0 | 1.2 | 4.0 | 6.0 | 2.0 | 6.0 | 8.0 | 4.0 | 8.0 |
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Armored thermocouple outer diameter and nominal length standard specifications |
Armored thermocouple outer diameter d d（mm） | φ 8 | φ 6 | φ 5 | φ 4 | φ 3 | 50 | 50 | 50 | 50 | 50 | 75 | 75 | 75 | 75 | 75 | 100 | 100 | 100 | 100 | 100 | 150 | 150 | 150 | 150 | 150 | 200 | 200 | 200 | 200 | 200 | 250 | 250 | 250 | 250 | 250 | 300 | 300 | 300 | 300 | 300 | 400 | 400 | 400 | 400 | 400 | 500 | 500 | 500 | 500 | 500 | 750 | 750 | 750 | 750 | 750 | 1000 | 1000 | 1000 | 1000 | 1000 |
| 1250 | 1250 | 1250 | 1250 |
| 1500 | 1500 | 1500 | 1500 |
| 2000 | 2000 | 2000 | 2000 |
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| 2500 | 2500 | 2500 |
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| 3000 | 3000 | 3000 |
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| 4000 | 4000 | 4000 |
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| 5000 | 5000 |
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| 7500 | 7500 |
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| 10000 | 10000 |
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| 15000 |
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Note: 1. The nominal total length L of the ¢3 insulated armored thermocouple shall not exceed 10000mm.
2, armored thermocouple outer diameter d ≤ ¢ 5mm, and has a splash-proof or waterproof junction box products, users should pay attention to the installation, the thermocouple exposed equipment must be equipped with brackets and other auxiliary support, increase stiffness, ensure Sturdy to prevent the junction box from shaking back and forth, damaging the thermocouple.
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structure |
Structural form of armored thermocouple material |
Working end (hot end) structure |
Mounting form |
| The fixture is for user installation. In addition to the non-fixed device products, the armored thermocouple fixing device has four types: fixed ferrule type, movable ferrule type, fixed flange and movable flange. The fixed ferrule type is fixed for the user, and the movable ferrule type user can be fixed multiple times. |
Armored thermocouple outer diameterd Casing diamete （mm） | φ 8 | φ 6 | φ 5 | φ 4 | φ 4 | φ 3 | φ 2 | M | M16*1.5 | M12*1.5 | S | 22 | 19 |
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Note: The number in the brackets is generally not used. If you need to order special specifications. |
Armored thermocouple free end (junction box) form |
The junction box is used to connect the free end of the thermocouple and the display instrument. At present, there are various structures such as simple type, splash proof, waterproof type, handle type, small junction box type and compensation conductor type. |
| With compensation wire |
| Splash proof |
| Waterproof |
| Handle type |
| Small junction box |
