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Filter Efficiency Formula:
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Filter efficiency measures how effectively a filter removes particles from a fluid stream. It is expressed as a percentage and indicates the proportion of particles captured by the filter compared to the total particles in the upstream flow.
The calculator uses the filter efficiency formula:
Where:
Explanation: The formula calculates the percentage of particles removed by the filter by comparing the number of particles that penetrate through the filter to the original particle count upstream.
Details: Filter efficiency is crucial for evaluating filter performance, ensuring air/water quality standards, maintaining system integrity, and determining when filter replacement is needed in HVAC systems, cleanrooms, and industrial processes.
Tips: Enter the number of penetrated particles and upstream particles. Both values must be positive numbers, and penetrated particles cannot exceed upstream particles for valid results.
Q1: What is considered good filter efficiency?
A: Efficiency requirements vary by application. HEPA filters typically have 99.97% efficiency for 0.3μm particles, while standard filters may range from 30-95% depending on the application.
Q2: How is particle counting performed?
A: Particle counting is done using specialized instruments like optical particle counters that measure and size particles in air or liquid samples.
Q3: Does efficiency change over time?
A: Yes, filter efficiency can change as filters load with particles. Some filters show increased efficiency initially due to particle buildup, while others may decrease over time.
Q4: What factors affect filter efficiency?
A: Particle size, filter media, face velocity, temperature, humidity, and filter loading all impact overall efficiency performance.
Q5: How often should efficiency testing be done?
A: Testing frequency depends on the criticality of the application. Critical environments may require continuous monitoring, while others may test quarterly or during routine maintenance.