This page covers the 40 mesh count of flour mill plansifter sieve frame: the woven specification per ISO 3310-1 cloth / mill OEM frames, the particle size it retains, the open area it presents to flow, and the neighbouring counts to step to when the separation requires it.
40 Mesh Specification Row (ISO 3310-1 cloth / mill OEM frames)
| Mesh count | Wire diameter (mm) | Aperture (mm) | Micron rating (u00b5m) | Open area (%) | Frame |
|---|---|---|---|---|---|
| 40-Mesh | 0.250 | 0.385 | 385 | 36.8 | Square 640 u00d7 640 |
40 Mesh to Micron & Aperture
| Openings per inch | 40 |
|---|---|
| Aperture (opening width) | 0.39 mm |
| Micron rating | 385 µm |
| Standard wire diameter | 0.25 mm |
| Open area | 36.8 % |
Aperture = (25.4 mm ÷ mesh count) − wire diameter. The micron rating equals the aperture in micrometres; actual retention also depends on particle shape and cake formation.
Wire Diameter Options at 40 Mesh
| Option | Wire dia | Aperture | Micron | Open area | Weight (SS) |
|---|---|---|---|---|---|
| Heavy wire | 0.325 mm | 0.310 mm | 310 µm | 23.8 % | 2.18 kg/m² |
| Standard wire | 0.250 mm | 0.385 mm | 385 µm | 36.8 % | 1.29 kg/m² |
| Fine wire | 0.188 mm | 0.448 mm | 448 µm | 49.7 % | 0.72 kg/m² |
Heavier wire adds strength and abrasion life but closes the aperture; finer wire opens the aperture and raises throughput at the cost of durability. Specify mesh count AND wire diameter to fix the aperture unambiguously.
Open Area & Flow at 40 Mesh
The standard 40 mesh weave presents an open area of about 36.8%. At this count the mesh presents little flow resistance; selection is normally driven by particle retention and mechanical strength rather than pressure drop.
40 Mesh Cloth Weight
Standard 40 mesh stainless cloth weighs approximately 1.29 kg/m² (density 7.93 g/cm³ basis; brass and copper weave roughly 10% heavier, aluminum about one third). Use this figure for roll handling and freight estimation.
Typical Applications for 40 Mesh Flour Mill Plansifter Sieve Frame
40 mesh flour mill plansifter sieve frame is commonly specified for general straining and sieving, paint and coating filtration, grease filters, insect screening, grain cleaning and pre-filtration ahead of fine media.
Plain, Twill or Dutch Weave at This Rating?
Plain square weave is the standard at this count: every opening is a true square of the stated aperture, retention is absolute for hard spherical particles, and the cloth is easy to clean.
What Flour Mill Plansifter Sieve Frame Does
Separating flour, semolina, middlings and bran in plansifters with tensioned sieve frames covered in stainless steel cloth matched to each mill stream.
Fitting & Care
- Re-tension or re-cover frames during planned maintenance; slack cloth loses capacity.
- Check that sieve cleaners move freely so cloth does not blind.
