1、 Strengthen the airtightness testing of the box body

The aging and deformation of the door seal is the main cause of cold and hot exchange, and it is necessary to use fluorescence leak detection method to regularly test the sealing system. For sealing strips with a gap of more than 0.1mm, they should be immediately replaced with weather resistant silicone seals, and ensure that the pressure sensor display value reaches 5kPa or above after the door is closed.

What to do if there is a large temperature difference in the constant temperature and humidity chamber

2、 Control system parameter calibration

Focus on verifying whether the ± 0.3 ℃ accuracy of the PT100 temperature sensor meets the standard, and check the proportional band and integration time parameter settings of the PID control module. It is recommended to use a standard temperature and humidity source for closed-loop calibration every quarter to ensure that the control deviation does not exceed ± 1% of the set value.

3、 Establish a preventive maintenance system

Clean the dust accumulation on the evaporator fins every month and replace the high-efficiency particulate air filter every 2000 hours of operation. The refrigeration system should check the refrigerant filling amount annually, maintain the compressor oil level at 2/3 of the window, and add high-temperature lubricating grease to the condenser fan bearings.

4、 Optimize sample loading plan

Follow the 'three zone principle' to arrange experimental items: the front zone is 30cm away from the air supply outlet, the rear zone is 20cm away from the air return outlet, and there is a buffer zone in the middle. Large volume specimens should use hollow brackets to ensure that the cross-sectional area of the airflow channel is not less than 40% of the box section. Special samples require the configuration of auxiliary circulating fans.

By implementing the above structured improvement plan, the temperature difference within the working range of the 30m ³ constant temperature and humidity chamber can be reduced from ± 2 ℃ to ± 0.5 ℃, meeting the environmental requirements of GMP standards.