Wedge Wire Screen Slot Size Guide: Profile Wire, Support Rod and Tolerance
A wedge wire screen slot size is the clear opening between adjacent profile wires at the screening surface. It is a functional dimension that influences particle retention, open area, flow and cleaning behaviour, but it cannot be selected from particle size alone.
Before specifying a slot, the buyer should define the separation objective, particle-size distribution, process medium, flow conditions, allowable pressure differential, screen form and inspection requirement. The profile wire and support rod must then be selected as parts of the same screen structure.
Do not order a wedge wire component by writing only “0.5 mm slot” or another isolated opening value. State the nominal slot, permitted tolerance, profile-wire cross-section, support-rod cross-section and spacing, material grade, finished-screen form, flow direction, operating conditions and inspection method. Slot size is not the same as woven-wire mesh count.
What Is Wedge Wire Screen Slot Size?
In a welded continuous-slot screen, shaped surface wires are arranged next to one another and attached to support members. The narrow opening at the working surface is the slot. The opening normally widens away from the screening surface because of the tapered profile.
This geometry is different from ordinary woven wire cloth. Woven mesh is commonly described by mesh count, wire diameter and aperture. A wedge wire screen is normally described by its slot opening, profile-wire geometry, support construction and finished form. A mesh number should therefore not be substituted for a wedge wire slot without a separately agreed technical basis.
| Term | What It Describes | What It Does Not Prove Alone |
|---|---|---|
| Nominal slot | Specified clear opening at the screening surface | Actual retention efficiency under every operating condition |
| Profile-wire size | Width, height, angle and section of the working wire | Finished-screen strength without the support design |
| Support spacing | Distance and arrangement of structural support members | Allowable load without the complete screen calculation |
| Open area | Proportion of projected surface available for flow | Guaranteed flow rate or pressure drop for an unspecified fluid |
Information Needed Before Selecting a Slot
Particle or Media to Be Retained
Use a representative particle-size distribution where possible, not only one average diameter. Particle shape, compressibility, agglomeration and orientation can change whether material bridges across, passes through or becomes lodged in an opening. For catalyst or resin retention, the operating condition of the media may differ from its dry delivered size.
Process and Flow Conditions
State whether the screen handles liquid, gas, slurry or dry solids. Flow rate, viscosity, temperature, solids concentration, flow direction and allowable pressure differential all affect the final design. A slot that retains the target material may still be unsuitable if it creates excessive pressure loss or plugs rapidly.
Cleaning and Operating Cycle
Identify forward flow, backwash, scraping, vibration, chemical cleaning or another cleaning method. Repeated pressure reversal and cyclic loading should be stated because they affect the support structure and weld design, not only the slot opening.
Profile Wire vs Support Rod
The profile wire and support rod perform different functions. Johnson Screens technical literature describes welded screen construction using V-shaped profile wire attached to an array of support rods at their intersections. The finished strength and geometry result from the complete arrangement, not from one wire dimension alone.
| Component | Primary Function | Details to Specify |
|---|---|---|
| Surface profile wire | Forms the screening surface and continuous slot | Profile designation or drawing, face width, height, angle, radii, material and condition |
| Support rod | Supports the working wires and transfers structural load | Cross-section, size, spacing, direction, material and straightness |
| Welded intersection | Connects the working surface to the supports | Welding route, distortion control and inspection requirements |
| Finished screen form | Establishes overall geometry and flow direction | Flat panel, cylinder, basket or custom assembly; dimensions and inlet direction |
SAKY STEEL supplies SBB stainless steel wedge profile wire and drawing-based profile options for downstream screen manufacture. Where a shaped structural member is required, review the D-type stainless steel support rod. Final screen capacity, slot performance and welding suitability must be confirmed for the complete design.
Slot Size, Profile Width and Open Area
For a simple projected surface made from parallel profile wires, a preliminary geometric open-area percentage may be expressed as:
This expression is a geometry check, not a hydraulic-performance guarantee. It does not include support members, blocked edge zones, frames, weld effects, fouling, fluid properties or the condition of a loaded screen. Use the complete finished-screen drawing and agreed test conditions when flow or pressure drop is a contractual requirement.
A narrower slot normally reduces projected open area when the profile width remains unchanged. Increasing profile-wire width may improve the working section but also changes open area and material usage. The selected combination must therefore balance retention, flow, mechanical duty and manufacturing feasibility.
Slot Tolerance and Inspection
There is no single slot tolerance that should be copied onto every wedge wire screen drawing. Capability depends on the nominal opening, profile dimensions, finished form, welding process, screen size and inspection basis. A supplier-specific capability value must not be treated as an industry-wide guarantee.
| Inspection Item | What to Define | Why It Matters |
|---|---|---|
| Nominal slot | Target opening and unit | Prevents ambiguity between inch, millimetre and micron descriptions |
| Permitted variation | Bilateral or unilateral tolerance and treatment of isolated openings | An average alone may hide oversized or undersized locations |
| Sampling plan | Number of readings and locations across each panel or cylinder | Slot variation may occur across the finished structure |
| Measurement method | Agreed gauge, optical method or other suitable procedure | Different methods and contact conditions may produce different results |
| Inspection record | Individual results, summary, drawing revision and traceability | Connects the measurements to the ordered component |
Feeler gauges or go/no-go gauges may be suitable for some openings. Optical measurement may be considered where the geometry, accessibility or required resolution makes contact measurement unsuitable. The method, calibration, orientation and acceptance rule should be agreed before production.
Material and Standard Requirements
ASTM A580/A580M-23 covers stainless steel wire, including shape wire in coils, for commonly used stainless grades. It can support material-order requirements for suitable profile wire, but it does not by itself define the finished wedge wire screen slot, support layout, weld quality or hydraulic performance. Those items require the customer drawing and supplementary purchase specification.
Grade selection depends on the full service environment. Type 304 is commonly considered for compatible general industrial conditions. Type 316 is often considered where improved resistance to chloride-containing or more demanding wet environments is required. Neither grade is corrosion-proof, and neither can be selected safely from the word “water” or “chemical” alone. State composition, concentration, temperature, deposits, cleaning chemicals and expected service life for material review.
What to Put on a Wedge Wire RFQ or Drawing
Frequently Asked Questions
What is a wedge wire screen?
It is a screening structure made with shaped working wires arranged to create continuous slots and supported by rods or other members. The exact construction may be flat, curved or cylindrical.
What wedge wire screen slot sizes are available?
Availability depends on the profile wire, finished-screen geometry, manufacturing route and required tolerance. Send the target slot, application and drawing for a feasibility review rather than relying on a universal online range.
Is slot size the same as mesh size?
No. Slot size is the clear continuous opening between adjacent profile wires. Mesh count normally describes the number of openings per unit length in woven wire cloth. The two descriptions are not interchangeable.
What is the difference between profile wire and a support rod?
The profile wire forms the working surface and slot. The support rod sits behind or beneath the working wires to provide structural support and welding contact. Both must be defined for the finished design.
Can slot size alone predict flow rate?
No. Flow also depends on total open area, screen dimensions, fluid properties, pressure differential, support obstruction, surface condition and fouling. Use an agreed test or engineering calculation for contractual performance.
Conclusion
A reliable wedge wire specification connects the required separation duty to the slot opening, profile-wire geometry, support structure, material, finished form and inspection method. The smallest possible slot is not automatically the best choice, and one published tolerance cannot represent every screen design.
For profile-wire procurement, provide a dimensioned cross-sectional drawing together with the grade, condition, tolerance, supply form and quantity. If the profile will be welded into a screen, also provide the intended slot, support arrangement and operating duty so manufacturability can be reviewed without assumptions.
Request Wedge Profile Wire and Support Rod Review
Send the profile drawing, stainless grade, slot requirement, support design, operating conditions, quantity and inspection requirements for technical and commercial review.
Post time: Oct-09-2026