TYLER

w    Aperture width
Distance between two adjacent warp or weft wires, measured in the projected plane at mid positions.

d    Wire diameter
Diameter of the wire in wire screens.

p    Pitch
Distance between the middle points of two adjacent wires. Nominally the sum of the aperture width w and the wire diameter d.   (p = w + d)

k    Warp
All wires running lengthwise in the screen as manufactured.

s    Weft
All wires running crosswise in the screen as manufactured.

Ao    Open screening area
Percentage of the surface of all the apertures in the total screening surface. Ratio of the square of the nominal aperture width w and the square of the nominal pitch p = (w+d), rounded to a full percentage value:
Ao = 100 (w : p)²

ρA    Mass per unit area
The quantity calculated using the following equation:

d  = wire diameter in mm
w = aperture width in mm
f   = type conversion factor (see ISO 4783-1: 1989, 
       Table 1)
ρ  = material density in kg je cm³ (see ISO 4783-1:
       1989, Table 2)

The equation gives the calculated mass per unit area in kg/m², although the actual value can be up to 3% lower.

When ordering industrial wire screens the following should be specified:

1. The quantity required and all dimensions of rolls, parts or rolls or cut-to-size pieces, including tolerances.
2. The aperture width w (if required with certified apertures) and the wire diameter d.
3. The material of the wire (alloy, grade or finish, preferably according to international or national standards).
4. Required type of screen according to ISO 4783-3: 1989, Table 3, if other than type A (type A = DOUBLE CRIMP SCREEN).
5. Flow direction of sieve material (see illustration)
6. Type of certification, if any.
7. Any other requirements not mentioned.

Wire Screen Sections with Hook Strips:

• Sketch or drawing preferred, together with an indication of the permissible tolerances.
• FL  full length  of hook strips
• Sp  tensioning measurements, tensioning length