Temperature instruments' types-part 2

Rosemount temperature transmitter's types

Digital thermometer

Digital thermometer uses temperature sensor to convert (temperature) into digital signal.

Then the temperature in digital form is displayed through the display (such as LCD, nixie tube, LED matrix, etc.), which can quickly and accurately measure the maximum value of human body temperature. Compared with the traditional mercury thermometer, it has the advantages of convenient reading, short measurement time, high measurement accuracy, memory and prompt sound. In particular, the digital thermometer does not contain mercury and is harmless to the human body and the surrounding environment. It is especially suitable for hospitals and families. The use method is divided into the following steps:

1. Before using the thermometer, disinfect the head of the thermometer with alcohol.

2. Press the switch, the buzzer will give out a beep immediately, and the display is shown in figure a for about 2 seconds.

3. Then the display shows the temperature of the last side measurement, as shown in Figure B (if the last measurement was 36.5 ℃), and the well lasts for about 2 seconds. Then the display may display as shown in Figure C. The "℃" symbol flashes, indicating that the thermometer is in the standby state. (in this case, when the room temperature is higher than 32 ℃, the thermometer will display the room temperature instead of the display, as shown in Figure D, and the "℃" symbol flashes continuously).

4. Use a thermometer to take your temperature. The temperature value displayed during body temperature measurement rises gradually, and the "℃" symbol flashes continuously.

5. When the rising speed of body temperature is less than 0.1 ℃ within 16 seconds, the "℃" symbol stops flashing, and the thermometer gives a beep prompt sound for about 5 seconds. At this time, the thermometer can read the displayed body temperature after measurement.

Mercury thermometer

The spilled mercury must be immediately collected with a dropper and brush, covered with water (preferably glycerin), and then sprinkled with sulfur powder at the polluted place. It can be cleaned only after there is no liquid (generally about a week).

1. Calibration shall be carried out before use (standard liquid temperature multi branch comparison method can be used for calibration or thermometer with higher accuracy can be used for calibration).

2. It is not allowed to use the measured value whose temperature exceeds the maximum scale value of this kind of thermometer.

3. The thermometer has thermal inertia and should read after the thermometer reaches a stable state. The reading should be taken in the direction of the highest tangent of the temperature convex meniscus and look directly.

4. It must not be used as a mixing rod.

5. The mercury thermometer shall be perpendicular or inclined to the flow direction of the measured working medium.

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

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

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