The drug stability testing chamber is a device that is widely used and highly efficient by most enterprises, especially for pharmaceutical companies. We want to investigate common issues with drug stability test kits. Firstly, we need to understand the meaning, technical principles, and operation process of drug stability test kits. Based on this, we need to understand the possible malfunctions of drug stability test kits. Finally, we need to understand simple self inspection.

1、 What is a drug stability test box?

The drug stability test chamber is used for intensive research in the pharmaceutical industry, medicine, biotechnology industry, and all related industries including life sciences. The GMP principle requires long-term stability testing conditions at 25 ℃/60% RH humidity. In the field of stability testing systems in the pharmaceutical industry, the standard for testing humidity at 40 ℃/75% RH for 6 months in accelerated testing is mainly used to simulate temperature, humidity, and light conditions in the environmental climate.

2、 What is the technical principle of the drug stability test box?

Technical principle:

(1) Control principle: The temperature and humidity sensor transmits the current temperature and humidity values to the controller. The controller compares the temperature and humidity values with the set values based on the current operating status, performs PID calculation, and determines the output power of heating and humidification. By controlling the solid-state relay, the heating and humidification connection time is controlled, that is, the percentage of connection of the controller per unit time. By continuously adjusting the heating and humidification output, the temperature and humidity are ultimately relatively stable.

(2) Principle of refrigeration and dehumidification: The compressor compresses the refrigerant (R134a) into a high-temperature and high-pressure gas, which is condensed into a room temperature and high-pressure liquid by the condenser. It is then sprayed into the evaporator through a throttling device for vaporization. The refrigerant vaporizes and absorbs a large amount of heat, causing the evaporator temperature to decrease. The evaporator absorbs the heat from the air passing through the evaporator and liquefies the water vapor in the air, resulting in a decrease in air temperature and humidity. The low-temperature and low-pressure gas is sucked back into the compressor and circulates in this way.

3、 Common problems and solutions for drug stability testing chambers?

1. The power indicator light is not on

Reason: ① The socket has no power supply ② The fuse is blown

Solution: ① Check the socket ② Replace the fuse

2. Set the temperature to 68 ℃ (or above 68 ℃), trigger an alarm to stop the machine, and then the temperature drops to indoor temperature

Reason: Ultra high temperature protection action (factory designed protection function, and very faulty. If there are special requirements, please specify them when ordering)

Solution: The temperature setting value should be less than 68 ℃

3. The deviation between the temperature window display value and the actual value is too large

Reason: Check if the temperature correction value SC1 is correct

Solution: The new machine is in a normal state with SC1=0 (within -0.5 to 0.5)

4. The compressor is cooling, but the temperature cannot be lowered, and there is a large temperature difference between the upper and lower layers

Reason: The cooling indicator light is on, the compressor is cooling, and the temperature cannot be lowered. Check if the items on the tray are too full, which is blocking the circulation of up and down air.

Solution: Remove the overfilled culture from each layer and leave one-third to half of the air ducts on each layer

5. Not heating (not heating up)

Reason: ① If the heating indicator light is not on, it is a control board fault. ② If the heating indicator light is on, it is a heating tube that has burned out

Solution: ① Replace the control board ② Replace the heating tube

6. Not cooling (not cooling down)

Reason: ① If the refrigeration indicator light is not on, it is a control board fault. ② If the refrigeration indicator light is on, it is a refrigeration system fault. ③ If the compressor starts or runs again. ④ If the delay time has not expired

Solution: ① Replace the controller ② Repair the refrigeration system ③ Please wait a moment

7. The heating or cooling indicator light is on, but it does not heat up or cool down

Reason: Refrigeration system malfunction or broken heating tube

Solution: Repair the refrigeration system malfunction or replace the damaged heating tube

8. Not humidifying (the humidification indicator light on the display screen is on, but the humidifier indicator light is not on)

Reason: ① Humidifier power switch not turned on ② Humidifier malfunction

Solution: ① Turn on the power switch of the humidifier ② Replace the humidifier

9. The humidification indicator light on the test chamber is on, emitting a humidification signal, but the humidifier is not humidifying.

Reason: ① Humidifier is short of water ② The water in the water tank is not properly drained; ③ Circuit board or humidifier malfunction

Solution: ① Fill the water tank with water ② Please align the position and gently press the water tank with force. ③ Replace circuit board or humidifier malfunction

10. The humidity cannot reach the set value (the humidification indicator light on the display screen of the incubator is on, and the humidifier indicator light is also green)

Reason: ① The humidifier is not turned on or the humidity and fog output are set too low. ② The temperature setting is too low, making it difficult to achieve low temperature and high humidity. ③ Humidifier base water mostly

Solution: ① Increase the mist output by adding humidity. ② Increase the temperature setting or customize non-standard products. ③ Pour out some water from the base

11. Excessive humidity

Reason: If the humidity is set to 60%, stop humidifying when the humidity reaches, but overshoot to 68%

The humidity has reached the set value, but the humidifier continues to humidify

The humidity outside is high, and the door is not closed properly

Solution: ① Reduce the humidity and fog output appropriately ② If there is a fault with the circuit board ③ Close the door properly

12. The printer is not printing

Reason: ① Printer has no power indicator ② Communication line is broken ③ Incorrect automatic printing parameter settings

Solution: ① Replace the printer power supply ② Connect the communication cable ③ Set the automatic printing parameter Cn=1

13. The buzzer sounds and the power indicator light flashes

Reason: Unstable power supply voltage

Solution: Check the power supply line, improve the power supply of the grid, or increase the voltage regulator power supply

14. The buzzer sounds and the temperature exceeds the set value by ± 4 ℃

Reason: ① Test chamber door not closed properly ② Refrigerant leakage ③ Circulating fan not running ④ Control board malfunction

Solution: ① Close the door, turn off the power for 2 minutes, and then restart the machine. ② Check for leaks, repair welding, and recharge the refrigerant

③ Replace the circulating fan ④ Replace the control board