High and low temperature test chamber inspection and operation test plan
1. Main Test Instruments and Devices: 1.1 Anemometer: A precision anemometer with an accuracy of at least 0.05 m/s is required for measuring air velocity in the test chamber. 1.2 Thermometer: The temperature measurement system must include a platinum resistance, thermocouple, or similar sensor. It should have a sensor time constant between 20 and 40 seconds, and an expanded uncertainty (K=2) of no more than 0.4 °C. 1.3 Surface Thermometer: This system uses platinum resistance or similar sensors and must also meet a sensor time constant of 20 to 40 seconds. Its expanded uncertainty (K=2) should not exceed 1.0 °C. 2. Test Conditions: 2.1 The test should be conducted under no-load conditions to ensure accurate results without external interference. 2.2 For cooling rate tests, the ambient temperature should not exceed 25 °C, and the cold power temperature should remain below 30 °C to maintain stable testing conditions. 3. Temperature Test Method: 3.1 Location and Number of Test Points: 3.1.1 In the test chamber, three horizontal layers are defined: upper, middle, and lower. The upper layer is located 1/10 of the chamber height from the top, the middle layer passes through the geometric center, and the lower layer is 10 mm above the lowest sample holder. 3.1.2 Test points are placed on three test faces. The central point is located at the geometric center of the chamber, while other points are positioned 1/10 of each side’s length away from the walls. If the chamber volume is less than 1 cubic meter, the distance should be at least 50 mm. 3.1.3 The number of test points depends on the chamber size. For chambers up to 2 cubic meters, 9 test points are needed. For chambers larger than 2 cubic meters, 15 points are required. For chambers over 50 cubic meters, additional points may be added as necessary. 4. Test Procedure: 4.1 Select the highest and lowest nominal temperatures within the chamber’s adjustable range. 4.2 Operate the chamber according to the low and high temperature programs. Once the center temperature reaches the desired level and stabilizes for 2 hours, record the temperature at all test points every minute for 30 minutes, totaling 30 readings. 5. Data Processing and Test Results: 5.1 Correct the measured temperature values using the calibration data from the instruments. 5.2 Remove any questionable or outlier data points. 5.3 Calculate the average temperature for each test point based on the 30 readings taken during the stabilization period. 5.4 Determine the temperature gradient by subtracting the minimum average temperature from the maximum average temperature. 5.5 Analyze temperature fluctuations and deviations to assess uniformity. 5.6 Ensure that the difference between the set temperature of the chamber control and the central test point meets the specified tolerance limits. 6. Test Method for Temperature Difference Between Working Chamber Wall and Working Space: 6.1 Placement and Quantity of Test Points: 6.1.1 Place a temperature sensor at the geometric center of the working space and surface sensors at the geometric centers of the inner walls of the six sides of the chamber. 6.1.2 If there is a lead hole or other device in the center of the wall, the test point must be at least 100 mm away from it. 6.2 Test Procedure: 6.2.1 Choose the highest and lowest nominal temperatures within the chamber’s adjustable range. 6.2.2 Allow the chamber to reach the test temperature and stabilize for 2 hours. Then, measure the temperature at all test points every 2 minutes for a total of 5 measurements. 6.3 Calculation and Evaluation of Results: 6.3.1 Correct the temperature readings using the instrument’s calibration values. 6.3.2 Calculate the average temperature for each test point separately. 6.3.3 Determine the percentage difference between the chamber wall temperature and the working space temperature to evaluate thermal uniformity. 7. Rising and Cooling Rate Test Method: 7.1 The test point is located at the geometric center of the working space. 7.2 Test Procedure: 7.2.1 Select the lowest and highest nominal temperatures within the chamber’s adjustable range. 7.2.2 Start the cooling source and reduce the chamber temperature from room temperature to the lowest specified temperature, then stabilize for 2 hours. Adjust the chamber to the highest specified temperature and monitor the temperature change from 10% to 90% of the range. Stabilize again for 2 hours, then return to the lowest temperature and monitor the temperature change from 90% to 10% of the range. 7.2.3 Record the temperature value every minute during both heating and cooling phases to analyze the rate of temperature change. Folder is specially used to hold the whole page of documents, the main purpose is to better save files, make it neat and regular.Folders are tools for storing, protecting and managing paper documents.Materials include PP, PVC, cardboard;There are parts of imitation leather, cloth and so on. Binder Rings,Ring Binders,Ring Folder Binder,Ring Pvc Binder shaoxing chaofeng stationery manufacturing CO.,LTD. , https://www.chaofengstationery.com
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