If you look closely, you'll notice that there's usually a metal mesh inside the pleated filter paper. In the industry, this is called an "inner liner" or "support mesh."

　　Many people think it's just for "aesthetics" or "shape retention," but its role is crucial:

　　1. Combating "Pulse Fatigue"

　　In hydraulic systems or engine operation, the oil doesn't flow smoothly but is filled with pressure pulses (like pressure waves from a heartbeat).

　　Without a liner: With each pressure pulse, the pleats of the filter paper repeatedly open and close like an accordion. Within minutes, the filter paper will break and tear due to metal fatigue.

　　With a liner: The metal mesh provides strong mechanical support, locking the shape of the pleats and allowing the filter cartridge to withstand tens of thousands of pressure impacts without collapsing.

　　2. Preventing "Pleat Closure"

　　When the filter cartridge has been used for a period of time, dirt accumulates on the surface, or the oil viscosity increases, the resistance to fluid flow through the filter paper increases.

　　Extreme pressure differentials can attempt to flatten the folds in the filter paper. Once the folds clump together, the filtration area decreases dramatically, rendering the filter cartridge unusable.

　　A robust mesh liner ensures that even under extreme pressure differentials, channels remain between the folds, guaranteeing that the effective filtration area is not reduced.

　　3. Our upgraded process

        Inner hook, outer flat + no welds throughout. Ordinary metal mesh may puncture the filter paper due to protruding welds, or collapse due to uneven support. Our new "inner hook, outer flat" structural design:

　　Protecting the filter paper: The flat outer design provides support without damaging the tightly fitted filter paper, avoiding the risk of breakage due to friction.

　　Strong support: Combined with a completely weld-free manufacturing process, not only are weak points eliminated, but the overall support is also exceptionally strong.

　　4. Details Reveal the Truth: A Comparison of Old and New Parts Reveals the Difference in Craftsmanship

　　Looking at the old part in your picture, the rusted and deformed metal frame is an inevitable result of the "weak support and easy wear" of ordinary filter mesh. In contrast, the new part on the right, with its "inner hook and outer flat, weld-free" filter mesh, is bright, smooth, and structurally robust, designed from the outset for high-pressure pulse environments.

　　This is not merely a difference in appearance, but a manifestation of a generational leap in craftsmanship: The rust and deformation of the old part is a microcosm of the common filter mesh's tendency to accumulate dirt at weld points and its weak structure, gradually failing under long-term pulse impact. The weld-free design of the new part eliminates the problems of weld point corrosion and stress concentration at the source. The inner hook and outer flat structure ensures even and strong support at every point, maintaining the frame's rigidity even after tens of thousands of pressure fluctuations, providing continuous and stable protection for the filter paper.

　　As mentioned earlier, the filter mesh is the "skeleton" of the filter element, and our craftsmanship makes this "skeleton" stronger and more durable—rust-free and deformation-free, this is the true "confidence" a filter element should possess under high-pressure conditions.