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How To Use The Surface Thermometer Correctly
- Mar 03, 2018 -

How to use the surface thermometer correctly

Before the use of a thermometer, it should:

1. observe its range - the range of temperature that can be measured. If it is estimated that the temperature to be measured exceeds the maximum temperature it can measure or is lower than the lowest temperature it can measure, it is necessary to replace a thermometer with a suitable range. Otherwise, the liquid in the thermometer may burst the thermometer or fail to measure the temperature.

2. recognize its minimum scale, so that the temperature can be read out quickly when it is measured.

When measuring the temperature of a liquid by a surface thermometer, the correct method is:

The glass bubble of the 1. thermometer is immersed in the measured liquid and does not touch the bottom of the container or the wall of the container.

2. the thermometer glass bubble is immersed in the measured liquid for a moment, and then the number of the thermometer is stable and then read again.

The glass bubble will remain in the measured liquid at 3. reading, and the line of sight is flat with the upper surface of the liquid column in the thermometer.

How to properly install and use the fractionating tower air inlet and return air outlet thermometer?

Answer: the fractionating tower air inlet and return air outlet thermometer is used for measuring the temperature difference. The inlet air temperature and air temperature difference back out of the tower called "hot end temperature", which is one of the important basis for the operation. A small air separation unit uses a glass thermometer to measure its temperature. If the thermometer is not installed correctly and the indicator is inaccurate, it may cause misoperation.

In the operation, there are several incorrect surface thermometers used as follows:

1) do not measure the temperature difference at the hot end. There are no thermometer joints in the pipes; some have thermometer joints, but no thermometers;

2) there is no thermometer joint, only the thermometer is directly tied to the pipe to measure the temperature.

3) the thermometer intubation pipe is directly installed on the outer wall of the pipe, and the temperature measurement site does not contact with the medium.

4) although the thermometer joint is inserted into the fluid tube, the temperature measurement area is still not in contact with the medium.

5) the thermometer itself is not allowed, the temperature of the reflux gas is higher than the air temperature, the temperature difference at the hot end is negative, and the problem is not found.

6) when the temperature is measured, the thermometer is drawn out of the casing and read again.

The correct installation and operation methods are: first, open the hole at the air inlet pipe and the reflux pipe about 1.6m away from the ground, and weld the thermometer connector with the main shaft at 45 degrees. If a platinum resistance thermometer or a glass rod thermometer with a metal shell is used, the temperature sensor points should be inserted into the main pipe inner diameter 1/3 to 1/2, so that the temperature sensor is aligned with the fluid. If a common glass rod thermometer is used, the T2 copper bushing with a diameter of 12mm * 1.5mm shall be used in advance, and the tail end will be welded and sealed. The length of the casing is about 100mm, and the length of the pipe should be inserted into the length of the pipe, depending on the diameter of the pipe, and then welded to the main pipe. In use, the glycerol should be injected into the copper sleeve to reduce the temperature measurement error. The thermometer used should be checked and the error should not be greater than 0.2 degrees Celsius. When the temperature is detected, the thermometer can not be drawn out of the casing.


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