Sick sensors – the seven basic types of temperature sensors

1. Thermocouples

Thermocouples are voltage devices that indicate temperature measurement when voltage changes. As the temperature increases, the output voltage of the thermocouple increases – not necessarily linear.

Thermocouples are typically located inside a metal or ceramic shield to protect them from exposure to a variety of environments. Metal-sheathed thermocouples are also available in many types of exterior coatings, such as Teflon, for trouble-free use in acid and strong alkaline solutions.

2. Resistance temperature measurement equipment

Resistance temperature measuring devices are also electrical. Instead of using voltage like thermocouples, it uses another temperature-dependent property of matter – electrical resistance.

The resistive equipment used can be divided into: metal resistance temperature equipment (RTD) and thermistor.

In general, RTDs are more linear than thermocouples. They are added in a positive direction, and as the temperature increases, the resistance rises. The type of thermistor construction is completely different. It is an extremely nonlinear, semi-conductive device, and the resistance decreases as the temperature increases.

3. Infrared sensor

Infrared sensor to wrong touch sensor. For example, if you lift a typical infrared sensor to the front of a table without touch, the sensor will use its radiation to tell you the temperature of the table – about 68°F at normal room temperature.

In non-touch ice water measurement, ice water is measured slightly at 0°C due to evaporation, which slightly lowers the expected temperature reading.

4. Bimetallic equipment

Bimetallic equipment takes advantage of metal swelling when heated. In these devices, two metals are bonded together and mechanically connected to the pointer. When heated, one side of the bimetallic strip will expand more than the other. And when the pointer is aligned correctly, the temperature measurement value is displayed.

The advantages of bimetal devices are portability and independence from the power supply. However, they are generally not as accurate as electrical devices, and you can't easily record temperature values like thermocouples or RTDs. However, portability is the absolute advantage of using a program correctly.

5. Thermometer

Thermometers are well-known liquid swelling devices and are also used for temperature measurement. In general, they fall into two primary categories: mercury types and organic (generally red) liquid types. The difference between the two is clear because mercury equipment has certain limitations in how it can be safely transported or delivered.

For example, mercury is considered an environmental pollutant and breakage may be dangerous. Before shipping, it is important to check the restrictions on the air transportation of mercury products at that time.

6. Condition change sensor

The change in condition temperature sensor measures the change in the condition of the material caused by the change in temperature, like the change from ice to water to steam. This type of device is available in the form of labels, pellets, crayons, or paints.

For example, tags can be used on steam traps. When the trap needs are adjusted, it gets hot; The white dot on the label then turns black to indicate a rise in temperature. Even if the temperature recovers normally, the white dot will stick to black.

The change in condition label indicates the temperature measurement in °F and °C. Regarding these types of devices, when the temperature shown is exceeded, the white point turns black; And it's an irreversible sensor that sticks to black once it changes color. Temperature labels can be useful when you need confirmation that the temperature is not exceeding a certain level, perhaps for engineering or legal reasons, during shipping. Because condition-changing equipment has the same resistance to electrical error as bimetallic tapes, it is advantageous in certain uses. Some forms of sensors of this series (lacquer, crayons) do not change color, and the symbols they make only disappear. Granular ones are visually deformed or completely abled.

Limitations include a relatively slow response moment. So, if you have a temperature spike that goes up and then goes down very quickly, there may be no noticeable reaction. The accuracy is also not as high as that of most other equipment commonly used in industry. However, they are often useful in the field of use where you need non-reversal indications that do not require power.

The principle of operation of other reversible labels is completely different from that of using liquid crystal displays. Depending on the temperature reached, the color appears changes from black to brown, blue, or green.

For example, a typical tag is completely black at temperatures that are sensing. As the temperature measurement rises, a color appears at e.g. 33°F – first blue, then green, and finally brown as it passes through the specified temperature. In any particular LCD device, you will generally see two adjacent dots – the blue dot is slightly lower than the temperature indicator, and the brown dot is slightly higher than the temperature indicator. This allows you to gauge the temperature, for example, between 85° and 90°F.

Although it is not completely accurate, it has the advantage of being a small, robust, non-electronic indicator that continues to update the temperature measurement.

7. Silicon diodes

A silicon diode sensor is a device that has been specially developed for low-temperature scales. Essentially, they are linear devices, with the conductivity of the diode increasing linearly in the low and low temperature regions.

No matter what kind of sensor you choose, it won't work on its own. Because most sensors are stacked in terms of temperature scale and accuracy, the choice of sensor will depend on how they are integrated into a system.

Sick sensors – the seven basic types of temperature sensors

Sick sensors – the seven basic types of temperature sensors

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