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Wedge Wire Filter Screen

Stainless Steel Wedge Wire Filter Screens: Precision Slot Tolerances & Heavy-Duty Mechanical Separation

Wedge wire filter screens (also known as V-wire or Johnson screens) deliver continuous slot openings, high open-area ratios, and non-clogging geometries for demanding solid-liquid and solid-gas separation processes. Unlike woven wire mesh or perforated plate, resistance-welded wedge wire resists mechanical fatigue, high differential pressure, and surface abrasion in harsh operating environments.

Every screen element is manufactured by resistance-welding precision V-shaped profile wires onto orthogonal internal support rods at every intersection point. This geometric structure creates a widening slot profile from the outer surface inward, allowing trapped particles to release downstream during backwashing or mechanical scraping.

Technical Specifications & Manufacturing Tolerances

Parameter	Standard Range	Custom Capability
Slot Width (Separation Gap)	20 µm to 3,000 µm (0.02 mm–3.0 mm)	±5 µm precision tolerance available
Profile Wires (V-Shape)	12S, 18S, 22S, 28S, 38S, 42S, 50S	Custom width/height ratios upon request
Support Rod Profiles	Q25, Q35, Q55, 10×2, 15×2, 20×3, 25×3, 30×3 mm	Flat bars, round rods, inverted V-bars, or teardrop shapes
Screen Configurations	Cylindrical (Radial/Axial), Flat Panels, Curved Sieve Bends, Conical Baskets	Custom 3D geometries via CNC machining
Flow Direction	Inside-to-Outside (ITO) / Outside-to-Inside (OTI)	Axial or radial flow alignment
Outer Diameters (Cylinders)	25 mm to 1,200 mm	Up to 3,000 mm welded sectional rings
Single-Length Capability	Up to 6,000 mm continuously welded	Custom cut-to-length segments

Alloy Selection & Corrosion Metallurgy

Material integrity determines component service life under chemical attack, slurry abrasion, and elevated working temperatures. Raw materials are sourced exclusively from certified mills, accompanied by mill test reports (MTR) adhering to EN 10204 3.1.

AISI 304 / 304L: General industrial applications, municipal water filtration, and food-grade processes without severe halide exposure.

AISI 316 / 316L: Superior molybdenum content for resistance to organic acids, industrial wastewater, and moderate chloride solutions.

Duplex Stainless Steel (UNS S31803 / S32205)

Yield strength double that of austenitic alloys, paired with exceptional resistance to stress corrosion cracking (SCC) in marine and high-chloride environments.

Super Duplex (UNS S32750 / 2507)

Applied in deep-sea intake screens and aggressive chemical processing plants requiring high mechanical yield and pitting resistance (PREN > 42).

Hastelloy C-276 / Monel 400

Extreme acidic media, wet chlorine gas, and oilfield refinery systems where standard stainless steel fails.

Industrial Applications & Structural Formats

Water Treatment & Intake Systems
Passive Water Intake Screens: T-bar and drum configurations installed in lakes, rivers, and coastal seawater intakes to meet aquatic life protection velocity standards.

Resin Traps & Water Strainer Nozzles: Installed in ion exchange vessels and carbon filters to retain process media while maintaining uniform flow distribution.

Food, Beverage & Brewing
Lauter Tun False Bottoms: Flat segmented panels featuring sub-millimeter slot tolerances for efficient wort filtration and mechanical grain rake clearance.

Sieve Bends (DSM Screens): Parabolic static screens utilizing gravity flow for starch dewatering and fruit juice pulp removal.

Pulp & Paper Processing
Pressure Screen Baskets: Heavy-duty cylindrical baskets engineered for high-consistency pulp screening, featuring hardened chrome or nickel coatings to combat wire wear.

Mining, Minerals & Petrochemical
Centrifuge Sieve Baskets: Balanced conical screen baskets subjected to high rotational stress in coal and mineral dewatering centrifuges.

Header & Hub Lateral Systems: Underdrain collectors for catalytic reactors, gas treatment vessels, and pressure filter units.

Model & Configuration Selection Matrix

★Slot Gap (Micron/MM): Determined by the particle d50/d90 distribution size to prevent bypass or immediate surface blinding.

★Profile Wire Geometry: Narrower wires increase open surface area and flow rate; wider wires increase structural rigidity and abrasive service life.

★Flow Orientation

Out-to-In (OTI): Surface wire on the exterior; support rods on the interior.
In-to-Out (ITO): Surface wire on the interior; support rods on the exterior (internal smooth surface for internal scraper systems).
End Fittings & Structural Reinforcement: Machined end rings, threaded connections, ANSI/DIN flanges, or quick-release clamps. Internal stiffening rings or external armor cages for high collapse-pressure requirements.
Surface Treatments: Electropolishing for sanitary food/pharma standards, passivating for chemical resistance, or hard-chrome plating for abrasive slurries.

Manufacturing Process & Quality Control

Precision slot uniformities and structural weld integrity are maintained through continuous monitoring at every stage of production:

Raw Wire Quality Inspection -> CNC Resistance Welding -> Mechanical Sizing & Cutting -> End Fitting Welding -> Passivation & Surface Finish -> Final QC & Slot Testing

Quality Inspection Protocol
Slot Uniformity Verification: Optical comparator and digital microscopic slot measurements taken across 20+ points per meter length.

Material Verification: Positive Material Identification (PMI) testing via portable XRF analyzers prior to production.

Weld Shear Strength Testing: Destructive shear sampling on weld joints to verify resistance against hydraulic surge shock.

Dimensional Inspection: Ovality, straightness, and concentricity tolerance checks using coordinate measuring equipment for rotating equipment parts.

Non-Destructive Testing (NDT): Dye penetrant inspection (DPI) on structural welds and hydro-testing for complete pressure vessel assemblies.

OEM Customization & Contract Manufacturing

We work directly with engineering procurement departments and equipment OEMs to supply drop-in replacement elements or custom-engineered screen assemblies.

01/

Drawing Integration: Direct processing of 2D/3D CAD models (STEP, DWG, DXF, SolidWorks).

02/

Sample Validation: Prototyping service available for dimensional fit and laboratory filtration testing before full batch production.

03/

Private Labeling & Serialization: Custom laser etching of part numbers, heat numbers, and client logos on end flanges or structural rims.

04/

Export Packaging: Fumigated wooden crates with moisture barrier wrapping and protective end caps to prevent edge deformation during ocean freight.

FAQ

Q: What is the main structural advantage of wedge wire over woven wire mesh?

A: Wedge wire features continuous welded joints at every wire-rod intersection, giving it superior mechanical strength and structural integrity under high differential pressure. Unlike woven mesh, which suffers from wire displacement and blind spots, wedge wire maintains fixed slot dimensions, has a higher open surface area, and features a non-clogging V-shaped opening that simplifies backwashing.

Q: How do you guarantee slot size accuracy across long cylindrical screens?

A: Cylindrical screens are produced on automated, CNC-controlled resistance welding machines. Profile wire tension, rotational speed, and electrical current are continuously adjusted via closed-loop feedback systems. Slot dimensions are systematically verified with optical gauges across multiple cross-sections during and after production.

Q: Can you supply raw material mill test reports (MTR)?

A: Yes. All shipments include EN 10204 3.1 Material Test Reports detailing chemical composition, heat numbers, and mechanical properties. Positive Material Identification (PMI) reports can also be provided upon request prior to dispatch.

Q: What is the difference between Radial In-to-Out and Radial Out-to-In construction?

A: In Out-to-In (OTI) construction, the smooth filtration surface is on the outside of the cylinder, with support rods running internally. In In-to-Out (ITO) construction, the smooth profile wire surface is on the inside, making it suitable for applications utilizing internal rotating scrapers or internal flow feeds.

Q: How do you prevent surface corrosion on welded stainless steel screens?

A: After welding and fabrication, components undergo chemical pickling and passivation to remove heat tint, free iron contaminants, and weld oxides. This restores the passive chromium-oxide layer across the entire assembly. Electropolishing is available for applications requiring low surface roughness (Ra < 0.4 um).

Q: What are the maximum length and diameter limits for continuous cylindrical screens?

A: Single-section cylindrical screens can be produced up to 6,000 mm in length and up to 1,200 mm in outer diameter. Larger diameters (up to 3,000 mm) are manufactured in segmented cylindrical sections and joined using full-penetration girth welds or heavy-duty flanged rings.

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