As a key equipment in the pharmaceutical industry, the long-term temperature and humidity precise control ability of the drug stability test chamber directly affects the reliability of drug stability test data, which in turn affects drug quality evaluation and safety assurance. To achieve this core function, it is necessary to rely on the collaborative operation of multiple systems, forming a complete precision assurance system from the control core to the structural design.
At the control core level, high-precision sensors and intelligent control systems form the "perception decision" center. The equipment is usually equipped with imported platinum resistance temperature sensors and capacitive humidity sensors, with temperature measurement accuracy of ± 0.1 ℃ and humidity measurement accuracy of ± 2% RH, which can capture subtle changes in temperature and humidity inside the box in real time. The control system adopts PID (Proportional Integral Derivative) algorithm, which dynamically adjusts the output parameters by continuously comparing the measured value with the set value. When the temperature is lower than the set value, the heating tube is started in stages to avoid local overheating; If the temperature is too high, start the refrigeration compressor and fan to quickly balance the temperature difference; When the humidity is insufficient, the ultrasonic humidifier atomizes pure water and spreads it evenly through the air duct. If the humidity exceeds the standard, the dehumidification module is turned on to ensure that there is no lag or overshoot in the temperature and humidity adjustment.
The refined design of temperature and humidity regulation components is a key support for achieving long-term stability. The heating system adopts a combination of stainless steel heating tubes and a uniform flow hood, and the heat is evenly transferred to various areas of the box through the air duct to avoid local high temperatures; The refrigeration system is equipped with a fully enclosed compressor and high-efficiency heat exchanger, combined with capillary throttling technology, to achieve stable refrigeration in low-temperature environments, and has automatic defrosting function to prevent frost from affecting heat transfer efficiency. In terms of humidity regulation, an external water tank and a built-in ultrasonic atomizer are designed separately. The water tank is equipped with a water level monitoring device, which automatically alarms when the water level is low, avoiding dry burning of the humidifier; At the same time, a condensation water collection device is installed inside the box to promptly discharge the moisture generated during the dehumidification process and prevent humidity rebound.
The sealing and insulation properties of the box structure provide a basic guarantee for precise control. The inner chamber of the test box is made of 304 stainless steel material, with a smooth and easy to clean surface and good thermal conductivity, ensuring uniform temperature inside the box; A high-density polyurethane insulation layer with a thickness of over 50mm is filled between the outer shell and the inner liner, which has a low thermal conductivity and can effectively isolate the impact of external environmental temperature fluctuations on the inside of the box. The box door is designed with double-layer tempered glass and filled with inert gas in the middle, which not only ensures the observation field but also enhances the insulation effect; The door seal is made of silicone rubber material, which has good elasticity and sealing performance. It is not easy to age after long-term use and avoids temperature and humidity leakage.
In addition, intelligent monitoring and fault warning systems further ensure long-term operational accuracy. The equipment is equipped with a high-definition touch screen, which can display temperature and humidity curves in real time, set multiple program operation modes, and meet the temperature and humidity cycle requirements of different drug stability tests; At the same time, the built-in data storage module can record at least 6 months of operating data, support USB export and remote monitoring, and facilitate data traceability and analysis. When sensor failure, compressor abnormality, low water level and other problems occur, the system will immediately issue sound and light alarms and automatically start protective measures, such as stopping heating and turning off the humidifier, to prevent the temperature and humidity inside the box from getting out of control, ensuring the safety of the test and reliable data.