Unit Leak Test & Unit Test to be performed for Freezer. Performing a unit leak test is crucial for maintaining the efficiency and reliability of freeze dryers in industrial applications. These tests ensure the system’s ability to meet performance standards under specified conditions.
By following detailed procedures, monitoring key parameters, and meeting acceptance criteria, users can ensure optimal functionality and compliance with quality standards. This article provides a step-by-step guide to conducting these tests, including performance benchmarks and troubleshooting tips.
Procedure for Performing a Unit Leak Test and Unit Test
- Start the unit leak test/unit test as per procedure, follow the steps of the cycle, and complete the result table.
- Ensure that chamber door is closed and all valves are in their nominal state
- Ensure that all utility supply is normal, e.g., compressed air, cooling water.
- Â Freeze Dryer is in Auto mode
- Set the performance test parameters as per the table.
- Start the Unit test on SCADA screen, follow the steps listed for the cycle, and
complete the result table.
1. Temperature Set Points
This section specifies the temperature values required for different stages of the test:
| Parameter | Set Value (Unit Leak Test) | Set Value (Leak Test) | Explanation |
|---|---|---|---|
| Starting Temperature for Shelves Cooling | 20.0°C | 20.0°C | Initial shelf temperature before cooling begins. |
| Set Point for Shelf Cooling | -40.0°C | -41.0°C | Target temperature for shelves during the cooling phase. |
| Set Point for Shelves Heating | 20.0°C | 21.0°C | Target temperature for shelves during the heating phase. |
| Condenser Temperature for Evacuation | -45.0°C | -45.0°C | The temperature the condenser must achieve before vacuum evacuation starts. |
| Condenser Temperature After Sterilization | -40.0°C | -40.0°C | Target condenser temperature after sterilization, ensuring readiness for the evacuation process. |
Temperature Set Points: The temperature set points define the required temperature values at different stages of the unit leak and unit tests. It includes starting temperatures for shelves cooling, target cooling and heating temperatures, and condenser temperatures before evacuation and after sterilization. These parameters ensure that the freeze-dryer operates within the desired thermal conditions for optimal performance.
2. Pressure Set Points
This section outlines the pressure levels required during the tests:
| Parameter | Set Value (Unit Leak Test) | Set Value (Leak Test) | Explanation |
|---|---|---|---|
| Set Pressure for Evacuation | 0.010 mbar | 0.010 mbar | Target vacuum pressure to achieve during evacuation. |
| Set Pressure for Leak Test Phase-1 | 0.013 mbar | 0.013 mbar | Pressure threshold for the first phase of the leak test. |
| Set Pressure for Leak Test Phase-2 | 0.016 mbar | 0.016 mbar | Pressure threshold for the second phase of the leak test. |
| Minimum Bellows Test Pressure | 300 mbar | 300 mbar | Minimum pressure required for the bellows component during the test. |
Pressure Set Points: The pressure set points outline the specific vacuum levels and pressure thresholds necessary during the unit leak and unit tests. Key parameters include the evacuation pressure, leak test pressures for different phases, and minimum bellows test pressure. These values are critical for assessing the vacuum system’s efficiency and leak integrity.
3. Time-Set Points
This section specifies the durations for various stages of the tests:
| Parameter | Set Value (Unit Leak Test) | Set Value (Leak Test) | Explanation |
|---|---|---|---|
| Time for Shelves Cooling | 50 minutes | 50 minutes | Time required for shelves to reach the cooling temperature. |
| Time for Shelves Heating | 60 minutes | 60 minutes | Time required for shelves to reach the heating temperature. |
| Condenser Cooling Time | 60 minutes | 60 minutes | Time required for the condenser to reach the specified cooling temperature. |
| Evacuation Time | 70 minutes | 70 minutes | Time required to achieve the target vacuum pressure during evacuation. |
| Leak Test Time Phase-1 | 60 minutes | 60 minutes | Duration of the first phase of the leak test. |
| Leak Test Time Phase-2 | 60 minutes | 60 minutes | Duration of the second phase of the leak test. |
| Leak Test Preparation Time | 60 minutes | 60 minutes | Time allotted for preparing the system for the leak test. |
| Evacuation Time Before Leak Test | 1 hour, 10 minutes | 1 hour, 10 minutes | Time required for evacuation before initiating the leak test. |
| Venting Time for Condenser Cooling | 60 seconds | 60 seconds | Time taken for venting during condenser cooling. |
Time Set Points: The time set points specify the durations for various stages of the testing process, such as shelves cooling, heating, condenser cooling, evacuation, and leak test phases. Proper adherence to these timeframes ensures the process achieves the desired conditions within acceptable limits, demonstrating the system’s reliability and consistency.
4. Additional Function
This section specifies other functional parameters required for the tests:
| Parameter | Set Value (Unit Leak Test) | Set Value (Leak Test) | Explanation |
|---|---|---|---|
| Venting Gas | Nitrogen/Compressed Air | Nitrogen/Compressed Air | The type of gas used for venting during the process. |
| Leak Test Only | Yes | No | Indicates whether the leak test is conducted independently or as part of a sequence. |
Additional Function: The additional function section focuses on auxiliary parameters, including the type of venting gas used (Nitrogen or compressed air) and whether the leak test is conducted independently or as part of a sequence. These details enhance the flexibility and functionality of the testing process, catering to specific operational needs.
Acceptance Criteria
- Shelf Cooling: Shelves must cool from 20.0°C to -41.0°C within 50 minutes.
- Shelf Heating: Shelves must heat from -41.0°C to 21.0°C within 60 minutes.
- Condenser Cooling: Condenser temperature must reach -41.0°C within 60 minutes.
- Evacuation: The system must achieve 0.01 mbar within 70 minutes.
- System Leak Rate: The leak rate must not exceed 0.01 mbar*liters/second.
Internal Linking
Explore additional resources to enhance your understanding:
- Temperature Control in Freeze-Drying Processes
- Refrigerating Compressor Failures in Freeze-Drying Processes
- Vacuum Performance Verification: A Comprehensive Procedure
- Shelf Heating and Cooling Rate Verification
Summary
This article outlines the procedural steps for conducting Unit Leak Tests and Unit Tests in freeze-dryers. By adhering to precise temperature, pressure, and time settings, the system’s performance can be validated. Key parameters, such as shelf cooling, heating rates, condenser cooling, and evacuation time, are detailed alongside acceptance criteria. These tests ensure the system meets stringent operational standards, promoting long-term reliability and effectiveness.
Conclusion
Proper execution of unit leak tests and unit tests is essential for ensuring the optimal performance of freeze-dryers. By meticulously following procedural guidelines, verifying key parameters, and adhering to system specifications, users can maintain operational excellence and compliance. Regular testing not only prevents system failures but also enhances overall productivity in freeze-drying operations.
FAQs
Q1: Why is the unit leak test important for freeze-dryers?
The unit leak test is vital to verify the integrity of the system, ensuring there are no leaks that could compromise vacuum performance and product quality.
Q2: What are the key acceptance criteria for the unit test?
Acceptance criteria include achieving specified shelf cooling and heating rates, condenser cooling, evacuation times, and maintaining a leak rate below 0.01 mbar*liters/second.
Q3: What happens if the system fails the unit test?
If the system fails, troubleshooting steps should be taken to identify and address issues such as leaks, faulty valves, or utility supply irregularities.