| [Outline on Pressure Drop vs. Flow Characteristics Test] To measure a filter's pressure drop vs. flow characteristics, a test circuit like the schematic shown below is needed. Water from the tank adjusted to specific test viscosities is passed through the test filter. Pressure drop from the upstream and downstream sides of the filter are taken. Filter pressure drop is then calculated afterwards. |
| [Outline on Filtration Accuracy(Filtration Efficiency) Test] To measure a filter's filtration accuracy(filtration efficiency), a test circuit like the schematic shown below is needed. Although, this time the drain portion of the circuit is used(drain valve is opened and tank return valve is closed.) Clean water from the tank adjusted to specific test viscosities is passed through the test filter. Test latex beads or test dust are then dispersed into the tank, and the fluid is allowed to pass through the test filter. At certain time intervals or sample fluid are taken from the upstream and downstream sides of the filter. Particle counts are then taken at several particle sizes to calculate for filtration efficiency. |
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| [Formula for calculating Pressure drop vs. Flow] Upstream (In) pressure of the filter and downstream(out) pressure are taken, then its difference is calculated. |
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| [Formula for calculating Filtration Accuracy(Filtration Efficiency)] Particle counts from automatic particle counters of fluid samples taken from the upstream and downstream sides of the filter are taken. Their difference and percentage are calculated for filtration efficieny. |
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| [Pressure drop vs. Flow Characteristics Data] Filter resistance is proportional to the viscosity of the fluid that passes through it. To show this, here are data for a filter's pressure drop vs. flow characteristics for water at 1cp and 20 cp, respectively. |
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Pressure Drop at 1cp |
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Pressure Drop at 20cp |
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| [Filtration Accuracy(Filtration Efficiency) Data] Filtration efficiency drops as the fluid viscosity rises. To show this, here are data for a filter's filtration efficiency for water at 1cp and 20 cp, respectively. |
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Filtration Efficiency at 1cp |
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Filtration Efficiency at 20cp |
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