The walk-in constant temperature and humidity test chamber can simulate various extreme weather conditions, such as high and low temperatures, as well as high and low humidity environments, in order to test the weather resistance and reliability of products. Most of the general information has been introduced. Today, let’s talk about two easily overlooked points: temperature change rate measurement and interrupt handling and response strategies.

1. Measurement of Temperature Change Rate

The measurement of temperature rise and cooling rate of a constant temperature and humidity testing machine needs to be carried out under standard conditions. The speed is defined as the average temperature change every 5 minutes, which should reach a rate of 5 ± 1 ℃/min, or the highest average temperature change rate that the test chamber can achieve. The testing time will be accurately recorded and used for analysis.

1.1 Measurement methods and steps

To determine the heating and cooling rates of a constant temperature and humidity testing machine, we first need to determine the temperature range for testing. Within the adjustable temperature range of the test chamber, we choose the lowest allowed temperature as the initial cooling temperature and the highest allowed temperature as the initial heating temperature.

Firstly, activate the cooling function to lower the temperature of the testing machine from room temperature to the set minimum cooling temperature, and stabilize at this temperature for at least 3 hours. Subsequently, raise the temperature to the set maximum heating temperature and stabilize at this temperature for at least 3 hours. Afterwards, the temperature drops again to the lowest cooling temperature. Throughout the entire heating and cooling process, we record temperature data every minute until the end of the entire experimental procedure.

1.2 Inspection and verification of sealing of refrigeration system

To ensure the sealing of the refrigeration system, we will use LED light sources or apply soapy water to check the sealing of various pipeline joints in the refrigeration unit. If no leakage is found during the inspection process, then the sealing of the refrigeration system meets the relevant standards and requirements.

1.3 Testing and Verification of Thermal Insulation Performance

The testing of insulation performance is conducted during the heating and cooling tests. After the temperature of the testing machine exceeds the maximum detection temperature and stabilizes for 3 hours. If the temperature of the surface, window frame, and other easily accessible parts of the testing machine does not exceed 50 ℃, it can be considered that the insulation performance of the testing machine meets the requirements.

Under low temperature conditions, when the ambient temperature is between 30-35 ℃ and the relative humidity is between 75% and 85%, there should be no obvious condensation on the surface, rear door, and sealing parts of the testing machine. Similarly, when the temperature of the testing machine is below the minimum detection temperature and stabilizes for 3 hours, we will visually observe the condensation on the surface of the box and the sealing area of the rear door. If there are no obvious water droplets or condensation, we can determine that the insulation performance of the testing machine is qualified.

2. Interrupt Handling and Response Strategies

Next, we will delve into how to handle these interruptions and ensure the effectiveness and accuracy of the experiment.

Firstly, we need to clarify the three main situations of experimental interruptions, namely interruptions within the tolerance range, interruptions due to insufficient experimental conditions, and interruptions due to excessive experimental conditions. The handling methods for these situations vary, but they all have a direct impact on the experimental results.

When the interruption of the experiment is due to problems with the test sample itself, such as sample malfunction or damage, we should first repair the sample to ensure its performance returns to normal before restarting the experiment. This is done to ensure the effectiveness and reliability of the experiment, and to avoid data distortion caused by sample issues.

In the face of experimental interruptions caused by external factors such as water, power, or equipment failures, we need to determine the subsequent operations based on the duration of the interruption. If the interruption time is within two hours, we can handle it according to the “under test condition interruption” specified in the relevant standards. This means that once external conditions are restored, we can continue the experiment from the interruption point without having to restart. However, if the interruption time is too long and exceeds an acceptable range, the experiment needs to be completely restarted to ensure the accuracy and reliability of the test data.

2.1 Interruptions within the tolerance range

As long as the test conditions are within the allowable error range, the interruption time can be included in the total test time. In this case, the interruption has a relatively small impact on the test results, so no special treatment is required.

2.2 Test condition

When dealing with interruptions caused by under test conditions, if the test conditions are below the allowed lower limit, we need to start from the point below the test conditions. Adjust the experimental conditions to the predetermined settings and run a complete experimental cycle. Ensure the completeness and accuracy of the experiment.

It is worth noting that if the interruption of the test has no direct impact on the test conditions, but the test sample fails during the test process, then the results of this test should be considered invalid. This is because the failure of the sample may have altered the initial conditions of the experiment, rendering the test results no longer of reference value.

In addition, when the walk-in constant temperature and humidity test chamber encounters external interference during the test process (such as water, power, or equipment failure), we should immediately close the chamber door to reduce the impact of the external environment on the test sample. If it is confirmed that the interruption has no impact on the sample and the equipment can resume normal operation in a short period of time, we can continue the experiment according to the relevant standards.

If you need to know the relevant parameters, specifications, and specific equipment plans of environmental testing equipment such as DGBELL walk-in constant temperature and humidity test chamber, you can contact us by email or phone, and our professional team will answer your questions.