Commonly used industrial temperature instrument - Pressure type thermometer

A, the working principle of pressure type thermometer pressure type thermometer principle is based on the sealing temperature measuring system of liquid evaporation changes in the relationship between saturated vapor pressure and temperature, and temperature measurement. When bulb feel temperature, saturated vapor produced the corresponding pressure in the closed system, cause the change of curvature elastic element, make its produce a shift in the free end, again by the displacement amplification mechanism of gear into the indicated value. Second, the pressure of thermometer thermometer by a temperature sensor, the pressure of capillary and bourdon tube pressure gauges. If as a gas recharge system, such as nitrogen, called inflatable pressure type thermometer, temperature limit of up to 500 ℃, the relationship between the pressure and temperature is close to linear, but wen package volume is big, thermal inertia. If filled with liquids, such as dimethyl benzene, methanol, bulb, temperature measuring range, respectively 40 ℃ ~ 200 ℃ and - 40℃~170℃。 If filled with low boiling point liquid, the saturation vapor pressure should be changed according to the measured temperature, such as acetone, used in 50 ℃ ~ 200 ℃. But due to the saturation vapor pressure and saturated steam temperature is nonlinear relationship, so the thermometer calibration is not uniform. Three, the characteristics of pressure type thermometer bulb must be immersed in all tested medium; Capillary the longest do not exceed 60 m; Instrument accuracy is low, but the ease of use, and shock resistant.