Pressure type thermometer
Pressure type thermometer works by gas-driven, bimetallic, or expansion principle. They can measure temperatures between -200...+700°C. All instruments are also suitable for thermowells.
The thermometer can measure the thermal state of homogeneous materials. The measurement system must be connected as closely as possible to the measured object. The most widely used measurement methods rely on temperature-related physical and material properties.
Bimetal thermometers are used with measurement systems in the form of spirals or spiral tubes. The measurement system consists of two sheets with different expansion coefficients, which are inseparably connected together. Through the mechanical deformation of the bimetal strip in the above-mentioned type of tube, a rotational movement caused by a temperature change is caused. If one end of the bimetal measurement system is firmly clamped, the other end will rotate the pointer shaft. According to EN 13190, the measuring range of the bimetallic thermometer is -70 ... +600°C, and the accuracy class is 1 and 2.
The expansion thermometer is composed of a temperature sensor, a capillary tube, and a Bourdon tube. The measuring system itself is filled with liquid. If the temperature changes, the internal pressure of the thermometer will also change. The pressure is transmitted to the pointer shaft through the tube, so the temperature value is displayed on the scale. It can also be measured from a remote measurement location using a remote capillary with a length of 500 to 10,000 mm. The scale range of the extended thermometer is between -40 ... +400°C and complies with the accuracy of EN 13190 Class 1 and Class 2.
Use a gas thermometer to connect the valve stem, capillary tube, and Bourdon tube together to form a unit. The instrument is filled with inert gas. If the temperature changes, the internal pressure will also change. The pointer moves under pressure through the measuring tube. In order to compensate for the ambient temperature, a bimetal element is installed between the movement and the measuring tube. The scale range of the pneumatic thermometer is between -200...+700°C, and the accuracy class is 1.
Machine glass thermometer
These thermometers are suitable for monitoring the temperature of gases, vapors, and liquids in containers and pipelines. The thermometer is housed in a box with cutouts for scale display. Machine glass thermometers are usually used with V-shaped watch cases.