Pressure type thermometer and bimetallic thermometer comparison principle

With the development of the industry, requires measuring instrument industry continuously improve. Care whether exports, form a complete set of machinery and the defense industry, scientific research, the automation of production are in urgent need of a mercury don't have to do packing, simple structure, small volume, strong and durable temperature measuring instrument - — The bimetallic thermometer. Pressure type thermometer and bimetallic thermometer, all belongs to the field indicates a thermometer of using the expansion principle, based on the principle, structure, and measuring the medium is different, its temperature range is not the same. Working principle of the pressure type thermometer pressure type thermometer is the use of gas inside the closed system, liquid and saturated steam pressure and temperature of the medium is a certain functional relation ( p= f( t) ) Features. Above medium as thermal material filling in the bulb, airtight measurement system composed of capillary tube and spring, when the temperature inside the bulb material by temperature effect, the pressure inside the closed system is changing, at the same time caused the spring tube white by the displacement, and then through the connecting rod and actuator drive pointer, directly on the dial shows the change in temperature. Working principle of the bimetallic thermometer bimetallic thermometer is to use two layers of different expansion coefficient of metal ( Or alloy) It firmly together, become a bimetallic strip, large expansion coefficient in two layers of a layer called the active layer 2, the expansion coefficient of a layer called the passive layer 1, the combination of the bimetallic strip fixed at one end, when it is affected by temperature effect, as a result of the active layer of white by zhong long, more than passive layer, the resulting torque, the bimetallic strip white bent by the client. The curvature and the physical properties of the material, the size of the material thickness ratio and temperature. When the physical properties of materials and thickness than fixed, the bend curvature is only related to the temperature change. Because white shaft by the end of the connection point, so when the temperature changes, the white shaft driven by the bent pointer, the pointer display the corresponding temperature value.