High-Flow Filter Cartridges with Unchanged Operating Pressure? Remember These Inspection Directions

However, the abnormal situation of unchanged pressure not only prevents operators from judging the cartridge’s status, but also may hide risks such as filtration system failure and medium leakage. So, when the pressure of a high-flow filter cartridge remains completely unchanged during normal use, from which aspects should we troubleshoot the problem? This article sorts out the core inspection directions for you.

1. First, Inspect Pressure Monitoring Equipment: Are the Data "Truly Reliable"?

The primary troubleshooting focus for unchanged pressure should be on the pressure monitoring link—if the monitoring equipment itself malfunctions, even the most accurate system status cannot be correctly fed back.

1. Pressure gauge/sensor failure: Check if the pressure gauge pointer is stuck or if the sensor has zero drift. Verify whether the pressure data returns to normal by replacing the pressure gauge with a new one or recalibrating the sensor. For digital pressure devices, also troubleshoot loose wiring connections and unstable power supply, and check if the signal conversion program of the digital display module has failed.
2. Unreasonable pressure tapping point location or blockage: Blockage of the pressure tapping pipe by impurities or colloidal substances will cause pressure transmission interruption. It is necessary to disassemble the pressure tapping pipe for cleaning to ensure unobstructed flow inside. Meanwhile, confirm that the pressure tapping point is located on the main inlet and outlet flow channels of the filter cartridge, away from dead corners or vortex areas, to avoid distorted monitoring data. In addition, the diameter of the pressure tapping pipe must match the pressure sensor; an excessively small diameter may cause pressure transmission delay or deviation.

1. Second, Inspect the Filter Cartridge Itself: Is the Filtration Function "Truly Effective"?

If the monitoring equipment is functioning properly, further inspect the filter cartridge itself to determine whether it is actually participating in the filtration process—this is one of the core reasons for unchanged pressure.

1. Improper filter cartridge installation: If the sealing end cap of the high-flow filter cartridge is not tightly attached to the filter housing, medium short-circuit will occur—the liquid flows out directly through the sealing gap without passing through the filter layer, resulting in no difference between inlet and outlet pressure. Disassemble the filter housing, check if the O-ring of the filter cartridge is damaged, aged or deformed. During installation, ensure no impurities on the sealing surface, and tighten the filter housing bolts following the principle of diagonal uniform fastening to ensure no gaps on the sealing surface.
2. Filter layer damage or failure: If the filter layer is torn or the welded joints are debonded during transportation, installation or use, the filtration medium will directly penetrate the filter layer, losing the function of intercepting impurities, and the pressure difference will remain unchanged. Remove the filter cartridge to check for damage or fiber shedding on the filter layer, or judge whether the filter cartridge has failed by testing the suspended solids concentration and particle size distribution of the filtered medium. For pleated high-flow filter cartridges, also check if the pleats are overstretched or deformed due to extrusion, to prevent filtration failure caused by flow channel deformation.
3. Mismatch between filter cartridge selection and working conditions: If the filtration accuracy of the cartridge is much lower than the particle size of impurities in the medium, or the cartridge’s flow capacity far exceeds the actual treatment flow rate, the cartridge will hardly get clogged, and the pressure difference will be difficult to manifest. In this case, verify the cartridge parameters against the working condition requirements and replace it with a cartridge with suitable accuracy and flux. If there are shock flow fluctuations in the working conditions, consider installing a pressure stabilizing device to avoid excessive deviation between the actual cartridge load and the designed value caused by sudden flow changes.

1. Third, Inspect System Piping and Working Conditions: Are the Operating Conditions "Truly Normal"?

After ruling out problems with the filter cartridge and monitoring equipment, abnormalities in the system piping and actual operating conditions may also cause the illusion of unchanged pressure.

1. Piping short-circuit or leakage: Check if the bypass valves upstream and downstream of the filter cartridge are not closed, and if there is leakage at pipe welds or flanges. If the medium flows directly through the short-circuit channel or leakage point, bypassing the main filter cartridge body, it will result in unchanged pressure. Meanwhile, troubleshoot whether check valves, control valves and other valves are stuck in the fully open state, losing their flow regulation function. For pneumatic or electric valves, also check if the actuator is working properly.
2. Actual treatment flow deviating from the designed value: If the actual operating flow rate of the system is much lower than the designed value, the filtration load of the cartridge will be insufficient, the impurity interception speed will be slow, and the pressure difference will not change significantly in the short term. Verify the flow meter data to confirm whether low flow is caused by pump failure, pipeline throttling, insufficient valve opening and other issues, and adjust to the designed working conditions. If the pump has cavitation, it will also lead to a decrease in actual output flow, and the cause of air intake into the pump must be promptly identified.
3. Abnormal impurity content in the filtration medium: If the impurity concentration in the medium to be filtered is much lower than expected, the dirt-holding speed of the cartridge will be extremely slow, resulting in long-term unchanged pressure. Determine whether the excessive cleanliness of the raw medium or the pretreatment system (e.g., pretreatment filter cartridges, sedimentation tanks) intercepting most impurities in advance by testing the turbidity and suspended solids content of the medium. If the pretreatment system has excessive interception, evaluate whether the pretreatment process has over-filtration problems to avoid resource waste.

1. Supplementary Inspection for Special Working Conditions: Do Environment and Medium "Have an Impact"?

In some special working conditions, environmental factors and medium characteristics may also indirectly lead to unchanged pressure, requiring targeted troubleshooting based on the actual scenario.

1. Excessively high medium temperature or abnormal viscosity: High temperature will reduce medium viscosity, decreasing the resistance of liquid passing through the filter cartridge; media with abnormally low viscosity will also keep the pressure loss of the cartridge at an extremely low level, manifesting as unchanged pressure. Verify that the medium temperature is within the tolerance range of the filter cartridge and test whether the medium viscosity meets the design standard. If the medium temperature exceeds the cartridge’s tolerance range, it may also cause softening and deformation of the cartridge material, further exacerbating filtration failure.
2. Filter cartridge covered with soluble or viscous substances: If the filtration medium contains water-soluble impurities, these impurities will gradually dissolve with the medium flow after adhering to the cartridge surface, failing to form a stable filter cake layer, and the cartridge pressure difference will be difficult to rise. If there are viscous substances in the medium, they may clog the filter layer pores without causing obvious pressure difference changes. It is necessary to analyze the medium composition, adjust the filtration process accordingly (e.g., adding filter aids) or replace the cartridge with materials with better resistance to solubility and viscosity (e.g., PTFE filter cartridges).

Conclusion

The unchanged pressure of high-flow filter cartridges involves problems in multiple aspects such as monitoring equipment, cartridge itself and system working conditions. Troubleshooting should follow the principle of "from easy to difficult, from outside to inside"—first rule out simple equipment failures, then conduct in-depth analysis of core issues with the cartridge and system. Timely and accurate troubleshooting can not only restore the effectiveness of pressure monitoring, but also ensure the stable operation of the filtration system, avoiding product quality problems or equipment damage caused by filter cartridge failure.