Introduction Of Various Temperature Sensors
There are hundreds of temperature sensors. Today we divide them into two categories, one is contact temperature sensors and the other is non-contact temperature sensors.
The characteristics of the contact temperature sensor: The sensor directly contacts the measured object for temperature measurement. Because the heat of the measured object is transferred to the sensor, the temperature of the measured object is reduced, especially when the heat capacity of the measured object is small, the measurement accuracy is low. Therefore, the prerequisite for measuring the true temperature of the object in this way is that the heat capacity of the object to be measured must be large enough.
The characteristics of non-contact temperature sensor: It mainly uses the thermal radiation of the object to be measured to emit infrared rays, so as to measure the temperature of the object, and it can be used for remote measurement. The manufacturing cost is relatively high, but the measurement accuracy is relatively low. The advantages are: it does not absorb heat from the object to be measured; it does not interfere with the temperature field of the object to be measured; continuous measurement does not produce consumption; the response is fast, etc.
In addition, there are microwave temperature measurement temperature sensors, noise temperature measurement temperature sensors, nuclear magnetic resonance thermometers, Moosbauer effect thermometers, Josephson effect thermometers, temperature graph temperature measurement temperature sensors, heat flow meters, Jet flow thermometers, cryogenic superconducting conversion thermometers, optical fiber temperature sensors, etc. Some of these temperature sensors have been used, and some are still under development.
Contact temperature sensor
1. Commonly used thermal resistance
Range: -260～+850℃; Accuracy: 0.001℃. After improvement, it can work continuously for 2000h, the failure rate is less than 1%, and the service life is 10 years.
2. Ultra-low temperature thermal resistance Two types of carbon resistors can measure the temperature of -268.8～253℃-272.9～272.99℃ respectively.
3. Ceramic thermal resistance The measuring range is -200～+500℃, and the accuracy is 0.3 and 0.15.
4. Tubing and cable thermal resistance The temperature measurement range is -20～+500℃, the highest limit is 1000℃, and the accuracy is 0.5.
5. Thermistor is suitable for use in high-sensitivity small temperature measurement occasions. The economy is good and the price is cheap.
Non-contact temperature sensing
1. Radiation pyrometer It is used to measure the high temperature above 1000℃. There are four types: optical pyrometer, colorimetric pyrometer, radiation pyrometer and photoelectric pyrometer.
2. Spectral pyrometer The YCI-I type automatic temperature measurement universal spectro pyrometer developed by the former Soviet Union has a measurement range of 400 to 6000 ℃. It uses an electronic automatic tracking system to ensure sufficient accuracy for automatic measurement.
3. Ultrasonic temperature sensor is characterized by fast response (about 10ms) and strong directionality. At present, there are products that can be measured to 5000℉.
