Thermometer is a tool to judge and measure temperature accurately. Glass tube thermometer uses the principle of thermal expansion and contraction to realize temperature measurement. Because the expansion coefficient of the temperature measuring medium is different from the boiling point and solidification point, the glass tube thermometers we commonly use are alcohol thermometer and mercury thermometer. Its advantages are simple structure, convenient use and relatively high measurement accuracy. Using it to measure temperature is not only simple and intuitive, but also can avoid the tolerance of external teletransmission thermometer. Mercury sprayed by mercury thermometers must be collected immediately with droppers and brushes, covered with water (preferably glycerin), and then sprinkled with sulphur powder on the contaminated area. It can be cleaned without liquid (usually about a week).

Using temperature, we first need to see its range (measurement range), and then see its minimum scale value, that is, the value represented by each cell. Choose the appropriate thermometer to measure the temperature of the object under test. When measuring, the bubbles of the thermometer should be in full contact with the object under test, and the glass bubbles can not touch the side wall or bottom of the object under test; when reading, the thermometer should not leave the object under test, and the eyes should be equal to the liquid level in the thermometer.

1. The calibration should be carried out before use (multi-branch comparison method of standard liquid temperature can be used to calibrate or thermometer with higher accuracy can be used to calibrate).

2. Temperature is not allowed to exceed the maximum calibration of the thermometer.

3. Thermometers have thermal inertia and should be read after the thermometer reaches a stable state. When reading, it should read in the highest tangent direction of the temperature convex meniscus and look straight at it.

4. Never use it as a stirring rod.

5. Avoiding violent vibration during use should cause drastic changes in temperature.

The mercury thermometer often breaks the mercury column. The elimination methods are as follows:

1. Cold repair method: The thermometer measuring bubble is inserted into the mixture of dry ice and alcohol (temperature must not exceed - 38℃) for cold shrinkage, so that all mercury in the capillary tube shrinks to the temperature measuring bubble.

2. Hot repair method: Insert the thermometer slowly into the constant temperature trough whose temperature is slightly higher than the upper limit of measurement, connect the mercury break part with the whole mercury column, then slowly take out the thermometer, and gradually cool it in the air to room temperature.

Alcohol thermometer broken line processing method:

1. Moving recovery:Hold the upper end of the thermometer by hand and swing or rotate rapidly until the alcohol column is restored.

2. Vibration recovery:Vertical down the bubble of the thermometer, gently shake on the finger or rubber until the alcohol column is restored.

3. Recovery of hot and cold water:If there is a safety bubble at the top of the thermometer capillary, the thermometer can stand upright, immerse in warm water, and slowly heat until the interrupted alcohol column is restored. Then the thermometer is immersed in the coolant, so that the temperature decreases gradually until the broken part of the alcohol column is retracted into the bubble, and the thermometer is taken out to make the temperature rise slowly to recovery.

4. After treatment:The repaired thermometer must be checked and verified by zero position before it can be used. When operating, it should be carefully to avoid damaging the thermometer.

Types: alcohol thermometer ,mercury thermometer

Back color: white,yellow