The temperature sensing element of the bimetallic thermometer adopts a multi coil straight spiral bimetallic strip. One end is fixed, and the other end (free end) is connected to the core shaft. The axial thermometer pointer is directly mounted on the core shaft. The radial structure indicator pin is connected to the core shaft through a corner spring. When the temperature changes, the free end of the temperature sensing element rotates, and the pointer driven by the core shaft indicates the change in temperature of the measured medium on the dial.
Electric contact thermometer, with movable contacts installed on the pointer and fixed contacts installed on the service pointer. The pointer contact rotates with temperature changes. When the temperature reaches or exceeds the set value, the contact closes and sends a signal to achieve automatic control and alarm.
Bimetallic thermometers can be divided into four types based on the direction of connection between the pointer plate and the protective tube: axial type, radial type, 135 ° directional type, and universal type
① Axial bimetallic thermometer: The pointer plate is vertically connected to the protective tube.
② Radial bimetallic thermometer: The pointer plate is connected parallel to the protective tube.
③ 135 ° directional bimetallic thermometer: The pointer plate is connected to the protective tube at a 135 ° angle.
④ Universal bimetallic thermometer: The connection angle between the pointer plate and the protective tube can be adjusted arbitrarily.
The biggest advantage of bimetallic thermometers is their good seismic performance and durability, but their accuracy is relatively low and can only be used in industry, with an accuracy level of 1-2.5.
Bimetallic thermometers are suitable for on-site detection of medium and low temperatures, and can directly measure the temperature of gases, vapors, and liquids with clear readings and good mechanical strength.
1. The thermometer comes in three types: axial, radial, and 135 °.
2. The accuracy level of the thermometer is level 1 and level 1.5.
3. The measurement range of the thermometer is shown in Table 1.
4. The time constant of the thermometer does not exceed 40 seconds.
5. The material of the protective tube is 1Cr18Ni9Ti stainless steel and molybdenum titanium, and it can withstand a nominal pressure of 6.4MaP.
6. There are three types of thermometers: ordinary type, outdoor type, and anti-corrosion type.
7. The contact points of the thermometer are upper and lower limits, single limit, and double upper limit (all normally open).
8. Contact rated power: 10VA (no inductive load).
Maximum operating voltage: 220V.
Maximum operating current: 1A.
9. The indicator head uses an ambient temperature of -40~85 ℃.
10. The indicator head is used in an environment with a humidity of 5-100%.
11. The WSS series bimetallic thermometer belongs to shock resistant mechanical instruments.
12. When measuring temperature, the entire 100mm length under the protective tube should be immersed in the measured medium to maintain temperature accuracy.
13. Execution standard: JB/T8803-1998.
