A reverse rolled wedge wire screen suits cylindrical filtration where solids remain inside and filtrate moves radially outward. The internal working surface carries continuous slots, while the support structure stays outside.
This inside-to-outside flow, often described as FITO, fits screw presses, self-cleaning filters, sludge dewatering, pulp processing, and other solid-liquid separation duties within the broader wedge wire screen range.
What Is a Reverse Rolled Wedge Wire Screen?
A reverse rolled slot tube uses V-shaped profile wire joined to support rods. Adjacent profiles form a continuous slot at the filtration surface, while the passage widens below the opening and reduces deep particle lodging.
How Does Inside-to-Outside Flow Work?
Feed enters the cylinder. Retained solids stay on the internal screening surface, while liquid passes through the slots and exits through the outer support structure. In screw presses and scraper-cleaned systems, this layout keeps cross supports away from the working surface.
The term “smooth internal screening surface” describes the structural arrangement. It does not mean the screen is polished, pickled, passivated, or electropolished.
How Does the Structure Solve Filtration Problems?
Reverse rolled construction addresses two common concerns: solids lodging in the slot and interference between cleaning hardware and support members.
Reducing Plugging and Flow Loss
The V-shaped opening is narrow at the retention point and wider below the surface. This geometry limits particle wedging and supports steadier flow as solids loading rises, especially with fibrous sludge, pulp, and food-process solids.
Keeping Screws and Scrapers Clear
External support rods leave the internal filtration surface comparatively unobstructed. A screw or static scraper can run along the cylinder without repeatedly crossing support members. Re-rolled cylindrical baskets therefore suit screw press and self-cleaning filter systems.
Which Applications Benefit Most?
Reverse rolled construction is most suitable when solids remain inside the cylinder and liquid must discharge radially outward.
Screw Presses, Sludge, Pulp, and Food Processing
Typical duties include screw press dewatering, wastewater sludge separation, pulp and fiber screening, and food or beverage filtration. Standard outside-to-inside cylinders still suit other processes, so flow direction remains a design variable rather than a default choice.
Which Parameters Matter Most?
Slot opening does not define performance by itself. Profile geometry, support-rod spacing, cylinder dimensions, material grade, open area, differential pressure, and cleaning method all affect the final design.
Practical Design Range
| Parameter | Reference Range |
| Slot Opening | 0.02 to 5 mm |
| Screen Length | Up to 6,000 mm |
| Screen Width | 25 to 1,200 mm |
| Materials | SS304, SS304L, SS316, SS316L, SS321, duplex stainless steel, and related alloys |
At Jingzhou Metal, we manufacture the upstream V-shaped profile wire used in screen fabrication. Standard and custom sections cover 0.5 × 1.0 mm to 5.0 × 10.0 mm, with dimensional tolerance down to ±0.01 mm for qualified profiles. That value applies to profile wire, not automatically to welded slot tolerance.
Why Wedge Wire Screen Open Area Matters
For a simple continuous-slot surface:
Open Area (%) = Slot ÷ (Slot + Profile Width) × 100
Two screens with the same 0.25 mm slot can have different open areas when profile width changes. Support spacing and cylinder geometry also affect hydraulic capacity and structural resistance.
How Do We Select the Right Configuration?
Selection normally starts with retained particle or fiber size, solids concentration, flow rate, viscosity, temperature, pressure, allowable differential pressure, and cleaning method.
Information Required for an RFQ
A technical specification normally includes material grade, slot opening, profile section, support arrangement, ID, OD, effective length, end connection, flow direction, and dimensional tolerances. Reverse rolled drawings should identify FITO flow and the internal working surface.
How Does Manufacturing Control Affect Screen Performance?
Finished slot consistency depends on upstream profile-wire accuracy as well as downstream screen fabrication. This is where control of the complete manufacturing chain becomes important.
From Profile Wire to Finished Screen
At Jingzhou Metal, we control profile development, mold maintenance, cold drawing, annealing, shaped rolling, fine drawing, screen fabrication, and inspection within one manufacturing system. Cold drawing improves dimensional consistency. Annealing restores ductility before further forming. Shaped rolling produces the required profile geometry, and fine drawing calibrates the final dimensions and surface finish.
During cylindrical screen fabrication, controlled welding joins the profile wire to support rods and establishes slot opening and support pitch. Forming or re-rolling then sets the required cylinder geometry and internal working surface. Final inspection checks slot consistency, dimensions, roundness, and equipment fit.
Infrared monitoring, 1D and 2D optical projection, spectrometric analysis, and tensile testing support dimensional and material control. We also develop custom profiles and screen configurations from drawings. The stated new-product development cycle is 7 to 15 days. This full-chain capability links profile geometry directly to finished-screen performance.
FAQ
Q1: How do axial and circumferential slots affect a wedge wire cylinder?
A: Slot orientation changes the relationship between flow, solids movement, support layout, and cleaning hardware. Equipment geometry determines the preferred orientation.
Q2: How does support-rod spacing affect performance?
A: Closer spacing increases structural support but reduces open flow area and adds weld points. Wider spacing can increase open area but requires adequate strength verification.
Q3: Can a reverse rolled screen directly replace a standard cylinder?
A: Not in every case. Flow direction, working-surface location, ID/OD, support arrangement, and equipment clearance must match the existing assembly.
Q4: Which dimensions are most critical in screw press service?
A: Internal diameter, roundness, effective length, slot consistency, and screw-to-screen clearance are key interface dimensions.
Q5: When is duplex stainless steel considered instead of 316L?
A: Duplex grades may suit higher structural loads or severe chloride and stress-corrosion conditions. Final selection depends on process chemistry, temperature, welding requirements, and design stress.