An absolute filter is a type of filter known for its high particle retention efficiency, specifically having a retention efficiency of 99.9% for all particles of the specified size.
Absolute filters are designed to provide a high level of filtration performance, capturing virtually all particles at or above a certain size rating. This characteristic distinguishes them from other filter types, such as nominal filters, where the retention efficiency is typically lower and can vary more widely for particles of the rated size.
Key Characteristics of Absolute Filters
The primary defining feature of an absolute filter is its reliable performance:
- High Efficiency: They guarantee the capture of at least 99.9% of particles at the stated micron rating.
- Precise Rating: The absolute micron rating signifies a clear cutoff point for particle retention.
- Reliable Performance: Due to their high efficiency, absolute filters are used in critical applications where removing specific particle sizes is essential for product quality or equipment protection.
The specific difference between nominal and absolute microns in a filter refers to the filter's ability to retain particles of different sizes. While nominal ratings might indicate an average particle size captured or a certain percentage capture (often lower than 99.9%), an absolute rating provides a much more stringent and guaranteed performance level at that specific size.
Applications
Absolute filters are often found in applications requiring high purity and consistent filtration, such as:
- Pharmaceutical manufacturing
- Food and beverage production
- Chemical processing
- Water purification for sensitive processes
- Hydraulic fluid systems requiring high cleanliness
Understanding the distinction between absolute and nominal ratings is crucial when selecting filters for specific tasks, especially when the reliable removal of nearly all particles of a certain size is paramount.
