Project requirement
A water-treatment customer reported using roughly 50–70 disposable 20 in × 4.5 in Big Blue cartridges per month in 5 µm and 20 µm grades. The customer asked whether a washable stainless element could replace them. The current cartridge size gives a starting housing reference, but it is not enough to establish an interchangeable design.
Engineering question
The first review should clarify whether the existing ratings are nominal or absolute, what particles and water chemistry are involved, the acceptable pressure drop, and the available cleaning process. End-cap and gasket dimensions also determine fit in the existing housing. A reusable design should be evaluated against these operating inputs and its cleaning cycle before any cost or waste-reduction claim is made.
Project status
The washable stainless replacement project was delivered. The available project summary does not document long-term cleaning cycles, service life or operating cost results.
Design review
A reusable stainless alternative to 20 in × 4.5 in disposable cartridges needs more than matching its envelope. Define what the existing 5 µm and 20 µm ratings mean, then examine end seals, allowable pressure loss, particle load and how deposits can be removed from the selected metal medium.
Inspection and acceptance
The replacement project was delivered. To assess a reusable element for the next installation, compare clean pressure drop, solids loading and flow recovery after cleaning under the same water quality and flow. Record cleaning time and replacement intervals to evaluate operating cost alongside filtration performance.
