@air
2025-04-11
Standard value of moisture content of freeze dryer
The standard value of moisture content of freeze dryers is usually based onPressure dew point temperature (Dew Point)It said that its standards need to be judged based on industry specifications and application scenarios. The following are specific instructions:
1. Conventional standard values
- Ordinary freezing dryer
- pressure dew point：+2℃ ~ +7℃（ISO 8573-1:2010 Class 3-4）
- applicable scenarios: General industrial manufacturing (such as pneumatic tools, purging cleaning).
- High-performance freeze dryer
- pressure dew point: Below-20℃ (requires pre-cooling or composite drying technology)
- remarks: This type of equipment is usually classified as a “pre-cooling type” or a “combination dryer”.
II. Key influencing factors
- inlet air conditions
- For every 10℃ increase in temperature, the dew point may deteriorate by 0.5℃ to 1℃.
- When the relative humidity is>80%, the capacity of the dryer needs to be increased.
- load rate
- Long-term overload operation (>80%) may cause the dew point to rise by 2℃ to 5℃.
- maintenance state
- Condensate water discharge is not timely: dew point drops by 3℃~7℃.
- Evaporator freezes: shutdown is required to defrost, and the dew point is out of control during this period.
3. Comparison of industry standards
| application field | Moisture content requirements (ISO 8573-1) | Recommended drying plan |
|---|---|---|
| general industrial | Class 4 (+7℃) | refrigerated dryer |
| precision machining | Class 2 (-40℃) | adsorption dryer |
| medicine/food | Class 1 (-70℃) | Refrigeration + adsorption combined dryer |
4. Selection suggestions
- Actual measurement verification: Install a dew point meter to monitor the outlet moisture content to avoid “false standards of theoretical values”.
- redundancy design: It is recommended to configure two dryers in parallel in key process sections to ensure dew point stability.
- energy-saving optimization: Install a precooler in front of the dryer to increase the dew point by 2℃~4℃.
Note: Some special environments (such as high temperature and high humidity areas) require customized dryers with increased refrigerant systems, and the cost may increase by 30%-50%.
