Thermometer in building plumbing, heating and ventilation and air conditioning engineering application

Building plumbing, gas and ventilation and air conditioning engineering in the at the same time to install many valve installation, instrument and apparatus. The valve is opening and closing, control the flow of the pipe fluid, flow velocity, flow rate and pressure pipeline accessories. Instrument is measuring the fluid flow in the pipeline, the temperature, pressure of pipeline accessories, etc. Appliance is fluid in pipe is the main thing. The types of thermometer bimetallic thermometer is used by the different expansion coefficient of the two metals constitute bimetallic element, also called a bimetallic strip as a temperature sensing element, used for temperature measurement instrument. Application range is wide, temperature measuring range is usually - 80 ~ 600 ℃, widely used in the site instructions, and can replace the glass liquid thermometer. Pressure type thermometer work based on the temperature changes airtight material volume change, to indirectly measure temperature caused by the pressure change. Pressure type thermometer has a simple structure, good resistance to vibration, explosion-proof, and yi to send wait for a characteristic, measurable - 50℃～+550℃。 Widely used in engineering survey, according to the thermal medium is usually divided into liquid pressure thermometer, gas pressure and steam pressure thermometer thermometer, etc. Thermoelectric effect thermocouple thermometer is used to measure temperature. With high measurement precision, wide measuring range, L80 ~ 1600 ℃) To facilitate remote transmission and the characteristics of the automatic recording. Thermal resistance thermometer using conductor or semiconductor temperature are different with different resistance to indirect measurement temperature. Has high measurement precision, is advantageous for the long distance, multipoint measurement. Wide measuring range is commonly - 120～+500℃( Under special circumstances to - 200～1000℃) Than the thermocouple thermometer is suitable for low temperature measurement, but the sensitivity than a differential thermocouple thermometer. Thermocouple and thermal resistance thermometer is used as a temperature sensor. Radiant thermometer is made based on the radiation effect of object. Has a temperature sensor is not contact with the media, do not have to reach the same temperature measured medium, measurement limit is higher, often referred to as the pyrometer. Choose the point 1) General scene shows the bimetallic thermometer and pressure thermometer; When there is a remote transmission function or a digital display, should be adopted thermocouple and thermal resistance temperature sensor, adding secondary instrument and display control device of the thermometer. 2) At level 3, should use pressure type thermometer, thermocouple and thermal resistance temperature sensor. 3) When the measured medium is corrosive medium, the thermometer should add protective casing, and the casing is adapted to be measured medium corrosion resistant materials. 4) When required by the system with automatic temperature control, electric contact thermometer should be adopted and thermocouple and thermal resistance temperature sensor. 5) The accuracy of the thermometer level should choose according to testing accuracy precision level. And the maximum temperature of the measured medium pulse should not be greater than the maximum range of the thermometer.