Many engineers when designing filtration systems only focus on filtration accuracy and do not pay enough attention to pressure drop. In reality, pressure drop is directly related to energy consumption and selection.
The pressure drop throughout the system includes several parts: pressure drop across the filter cartridge itself, pressure drop in pipes and valves, and local losses from sudden contractions or expansions at inlets and outlets. Filter cartridge pressure drop is related to accuracy, flow rate, and medium viscosity.
The greater the flow rate, the higher the pressure drop, but it is not a linear relationship. Medium viscosity has an even greater impact. At the same flow rate, doubling viscosity may increase pressure drop two to three times. Therefore, projects in cold regions during winter need to pay special attention to this.
Another often overlooked issue is pressure drop after filter cartridge clogging. When a filter cartridge has been used for some time, the pressure drop of the surface clogging layer may exceed that of the filter cartridge itself. If the system design did not leave enough margin, it may result in insufficient pump power and serious flow reduction. Generally, 50% pressure drop margin should be reserved during design.
