Of glass liquid thermometer calibration of technical requirements in which several?

Many people have used glass liquid thermometer, but don't know how to check, more do not know what are the requirements verification technology! Tell me the (instrument will give you today 1) Thermometer should be bright and clean and transparent glass, can not have cracks and impact strength of the defects, within the scope of the ruler can not have spots, bubbles and defects affect reading. （ 2) Heat pipe filled in liquid and liquid thermometer temperature liquid should be pure, no bubble and impurities. Liquid column without interruption, put back the clock, gravity and difficult. Warming may appear obvious retention or jump phenomena, cooling may not be on the wall with droplets or color. （ 3) Staff and marking of thermometer scale dividing line with spool perpendicular to the center of the capillary. Dividing line, Numbers, and other marks should be clear and accurate. （ 4) Thermal bubble, bubble and security bubble rod type among the thermal bubble diameter of the thermometer should not be greater than the diameter of the glass rod. Among the thermometer bubble top away from the main line bottom line the first scale distance shall not be less than 30 mm. Thermometer security bubble water droplets shaped, the top half a ball. （ 5) Stability value standard and work made of glass liquid thermometer after stability test, its zero position error of the rising and falling all shall not be more than 1/2 degree value. （ 6) Accuracy thermometer permissible error limit value determined by the measurement range of the thermometer and dividing value, including full immersion type thermometer should comply with the provisions of the error.