One-sentence answer: The water purifier filter housing is a plastic pressure-bearing part, with the upper and lower covers joined by hot plate welding or ultrasonic welding. Cold solder joints, shrinkage cavities, and poor sealing at the inlet/outlet will cause water seepage or even bursting. Using the CTS Sentinel A28 differential pressure leak detector to compare a master part with the part under test enables stable judgment at low pressure on plastic parts, making it suitable for 100% inspection on high-volume filter housing production lines.
A pressurised plastic part under continuous mains pressure and water hammer; a weak weld can turn into a leak or burst months later
The weld strength of hot plate welding and ultrasonic welding depends on heating time, press-fit depth, and holding time. Parameter drift produces cold solder joints and internal shrinkage cavities, while the appearance remains completely normal.
The filter housing continuously bears tap water pressure and the impact of water hammer from on/off cycles during service. No leakage in the short term does not mean no cracking in the long term; weld defects will develop into seepage or bursting after several months.
Unlike ordinary leaking parts, once the filter housing ruptures under supply pressure, it will release a large amount of water instantly, possibly damaging furniture and appliances. Housing rupture in hot water systems also carries a risk of personal injury.
Water purifier filter elements are fast-moving replacement parts with high output and low unit price. The test solution must balance judgment reliability with per-piece cost.
Sealing locations:
Consequences of leakage: In mild cases, water seepage soaks cabinets and floors and damages surrounding appliances; in severe cases, the weld cracks under supply pressure and water hammer, causing extensive water leakage and property loss. At the same time, external contaminants may intrude through the damaged area, affecting the quality of the output water.
The filter housing is a small-volume, extremely high-volume, plastic pressure-bearing workpiece:
Because weld defects are random and are not correlated with the batch's visual yield, and the consequence of failure is water leakage and possible bursting, which affects users' property and safety. Sampling inspection cannot cover individual parts with localized cold solder joints in the weld. Piece-by-piece 100% inspection with records is the common practice for this type of pressure-bearing plastic part.
Yes. Flash prevents the plugging fixture from fitting tightly against the housing, creating a false leak on the fixture side, and may also push up the fixture and cause sealing failure. The correct approach is to clean the flash after the weld has cooled, then perform the air tightness test, and include the fixture mating surface in the daily check.
Set it according to the product's pressure resistance and service pressure definitions, usually below the safe allowable value of the housing structure while retaining sufficient judgment margin. The upper pressure limit must be confirmed jointly by R&D and process engineering and written into the process documents, then controlled uniformly by the A28 test program. On-site personnel must not raise it without authorization to improve sensitivity.
For sealing tests of water purifier filter housings, the key is to intercept the random weld defects piece by piece before assembly and shipment. The CTS Sentinel A28 achieves stable judgment at low pressure through differential pressure comparison. Together with custom-formed plugging fixtures and 32 test programs, it is suited to 100% inspection and batch traceability on high-volume filter housing production lines.
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