The airflow in a mesh‑type high‑efficiency coating machine (also known as a fluid‑bed coater) follows a bottom‑to‑top overall path, yet internally it exhibits a composite pattern of "annular/atomised upward injection from the bottom + negative‑pressure suction exhaust at the top." Specifically, air is drawn into the intake ports at the bottom of the machine bed, passes through precision filters and regulators, and then rises in an annular or atomised pattern through the coating material bed. At the top, an exhaust system (including a damper and exhaust fan) removes the dust‑laden and moisture‑carrying air, completing a full heat‑and‑mass exchange cycle.
In this process, the deflection angle of the bottom guide vanes, the mesh size of the filters, the opening ratio of the air‑distribution plate, and the clearance between the top exhaust port and the bed surface collectively determine the uniformity of air penetration and the pressure drop distribution across the material layer. For example, if the bottom orifice plate has uneven openings, air will preferentially "channel" through low‑resistance zones, causing over‑drying on one side and insufficient film build‑up on the other. If the top exhaust opening is off‑centre, suspended dust may segregate, affecting final product appearance.
Hansheng Automation offers customised solutions for these critical airflow components. Based on your actual material bulk density and particle size distribution, we can redesign the bottom air‑distribution orifice plate with variable‑density hole arrays (denser at the centre and sparser at the periphery, or vice versa), using 316L stainless steel or corrosion‑resistant coated materials, with laser‑cut holes ensuring burr‑free edges and roundness tolerance ≤0.03 mm to avoid turbulent flow. We can also custom‑manufacture the guide cone and adjustable baffles inside the top exhaust hood, ensuring uniform negative‑pressure distribution across the entire bed surface and reducing local dust accumulation. For clean‑room applications, we offer mirror polishing and quick‑clamp fittings for easy cleaning and validation.
Moreover, in mesh‑type coaters, the bottom inlet air often also serves to fluidise or "throw" the material-beyond drying, it helps suspend or semi‑suspend the particles, promoting even coating liquid coverage. This function imposes stricter requirements on the orifice inclination angle and aperture ratio. We utilise 5‑axis machining centres and EDM perforation equipment to produce custom "jet‑micro‑hole" structures with specific inclination angles per customer drawings, creating rotational or wave‑like disturbances in the upward airflow to enhance mixing while keeping pressure losses within design limits.
In summary, while the airflow direction in a mesh‑type high‑efficiency coater appears simply "bottom‑up," achieving uniform, controllable, and efficient distribution critically depends on the geometric precision and surface quality of components such as the bottom orifice plate, top exhaust guides, and sealing rings. Hansheng Automation is committed to providing made‑to‑print customisation, dimensional optimisation, and material upgrades for these parts to coating equipment users and manufacturers-helping you significantly improve coating uniformity and drying efficiency through targeted local modifications, without replacing the entire machine, and extending the service life of your equipment.
