How to check the high and low temperature box

High and low temperature test box acceptance test method:

1, the main test equipment and devices:

1.1 Anemometers: Anemometers with a sensing capacity of not less than 0.05 m/s 1.2 Thermometers: Temperature measuring systems consisting of platinum resistors, thermocouples or other similar temperature sensors and meeting the following requirements: Sensor time constant: 20S~40S; Uncertainty of temperature measurement system expansion (K=2): no more than 0.4°C

1.3 Surface thermometer: Measurement system made of platinum resistance or other similar sensors and meeting the following requirements: sensor time constant: 20S~40S; expanded uncertainty of temperature measurement system (K=2): no more than 1.0°C

2. Test conditions 2.1 Test When the cooling rate test is performed under no-load condition 2.2, the ambient temperature should not be higher than 25°C, and the cold power temperature should not be higher than 30°C.

3. Temperature Test Method 3.1 Location and Quantity of Test Points 3.1.1 The three test levels of upper, middle and lower levels shall be defined in the contents of the chamber of the test chamber, referred to as the upper, middle and lower levels, and the distance between the upper level and the top surface of the studio is The height of the studio is 1/10th. The middle layer passes through the geometric center of the studio and the lower layer is 10mm above the lowest sample rack.

3.1.2 The test points are located on three test surfaces. The center test point is located at the geometric center of the studio. The distance from the rest of the test points to the workroom wall is 1/10 of the length of each side, but it is less than 1 cubic meter for the working chamber. Test box, the distance is not less than 50mm

3.1.3 The relationship between the number of test points and the size of the working chamber is: when the working chamber volume is no more than 2 cubic meters, the testing point is 9; when the working volume is more than 2 cubic meters, the testing point is 15; when the working room When the volume is greater than 50 cubic meters, the number of temperature test points may be appropriately increased. 4. The test procedure 4.1 is within the adjustable range of the test chamber temperature. The procedure of selecting the highest nominal temperature and the lowest nominal temperature 4.2 to make the test chamber at low temperature after high temperature Running, the temperature in the center of the workspace reaches the test temperature and stabilizes 2H, and the temperature of all test points is tested in the first minute of 30 minutes for a total of 30 times. 5. The data processing and test results 5.1 The measured temperature data , According to the correction value of the test instrument to make corrections 5.2 Remove suspicious data 5.3 Calculate the data measured in the constant temperature stage Calculate the average temperature of each measured value 30 points 5.4 Calculate the temperature gradient: the average value of the temperature minus the average value of the minimum temperature Value 5.5 Calculation of temperature fluctuation, temperature deviation 5.6 The difference between the set value of the instrument control instrument and the central test value should meet the tolerance requirement.

6. Test method for the temperature difference between the inner working wall and the working space 6.1 Location and number of test points 6.1.1 Place a temperature sensor in the center of the working space, and place a surface in the geometric center of the six inner walls of the working room. Temperature sensor 6.1.2 If there is a lead hole or other device in the center of the working chamber wall, the distance between the test point and the hole wall or other device should not be less than 100mm

6.2 Test Procedure 6.2.1 Within the adjustable range of the test chamber temperature, select the highest nominal temperature and the lowest nominal temperature as the test temperature 6.2.2 At the geometric center point of the working space for the first time to reach the test temperature and stable 2H, Test the temperature of all test points once every 2 minutes, total test 5 times 6.3 Calculation and evaluation of the test results 6.3.1 Test the temperature value according to the correction value of the test instrument 6.3.2 Calculate the temperature of each test point separately Average 6.3.3 Calculate the percentage of the difference between the studio thermodynamic wall and the thermodynamic temperature of the chamber. 7. Test method for temperature rise and cooling rate 7.1 Test point is the geometric center of the workspace 7.2 Test procedure 7.2.1 Adjustable temperature in the test chamber Inside, select the lowest nominal temperature as the minimum specified temperature, and the highest nominal temperature as the highest specified temperature 7.2.2 Turn on the cold source, reduce the test chamber from room temperature to the minimum specified temperature, stabilize the 2H, adjust to the maximum specified temperature, and test the chamber The temperature is increased from 10% of the temperature range to 90% of the time; the test chamber is stabilized at 2H for the maximum specified temperature, and then adjusted to the minimum specified temperature. The test chamber temperature is 90% of the temperature range. To 10% of the time.

7.2.3 Record temperature value once every 1 minute during heating or cooling process