Glossary to Industrial Screening

clamp bar

Metal edge used to stretch and/or to fasten the screen section.

crimp

Successive bends in a wire which result from preforming or weaving.

feed

Material supplied to a screen for a screening process.

fines

Particles smaller than a specified size.

frequency

For vibrating screens, the number of oscillations made by the screen per unit of time, expressed in hertz (Hz).

grizzly

Rugged screen com­prising fixed or moving bars, discs, or shaped tumblers or rollers, normally used for screening comparatively large particles, e. g. greater than100 mm.

guard screen

Screen used to prevent the entry into a machine of coarse particles which might interfere with its operation.

horizontal screen

Vibrating screen with a motion which is substan­tially in a straight line in the vertical plane, normally installed horizontally, but may be inclined up to 8°.

high speed screen

Inclined screen, with a rectilinear or circular oscillating motion, normally operated at a frequency greater than 20 Hz.

hook strip

The fabri­cation on the edges of a screen section for holding or tensioning purposes.

inherent moisture; contained moisture

Liquid, usually  water, held within a sample of a material, normally expressed as a percentage of the sam­ple mass.

inclined screen

Vibrating screen with a rectilinear or circular oscillating motion, normally installed at an angle between 10° and 36°.

mesh count

Number of aper­tures per unit of linear measure in a woven wire cloth or wire screen.

nominal size

The particle size used to describe a product of a sizing operation.

near-sized material; near­ mesh material

Particles approximat­ ing in size to the aperture size of the screening surface.

overflow

That portion of the feed discharged from the screening surface without having passed through the apertures.

oversize

Screened product of a size greater than a specified size.

particle (deprecated: grain)

Discrete element of the material to be screened regardless of its size.

particle size; sieve size of a particle

Smallest sieve aperture through which a particle will pass if pre­ sented in the most favourable attitude.

per cent solids

Ratio of dry solids to the total solid-liquid mixture of material, expressed as a percentage by mass.

percentage open area

For woven wire cloth and wire screens, the ratio of the total area of the apertures to the total area of the cloth or the screen.

plain weave

Weave in which every warp wire crosses alternately above and below every weft wire and vice versa.

pegging

The condition where particles wedge in the screen apper­tures.

pitch

Distance between cor­responding points of two adjacent apertures in a woven wire cloth, a wire screen or a perforated plate.

product

In general, the mate­ rial resulting from any operation. In par­ticular, the final material produced from a series of operations; e. g. screened product, finished product,etc

relative  density (deprecated: specific gravity)

Ratio of the mass in air of a solid particle of a given volume to the mass of an equal volume of water.

resonance screen

Screen with a period of oscillation close to the natural period of oscillation of the resili­ent mounting.

relieving deck

Screen, mounted above another  screen, with apertures normally at least twice the size of those in the lower deck, used to reduce the load and wear of the lower screening surface.

reciprocating screen; jig­ ging screen

Screen or pair of screens to which a combined horizontal and vertical motion is imparted by a crank­ shaft and connecting rods, the screen­ ing surfaces being horizontal or in­ clined at a small angle.

revolving screen; trommel

Screen in which the screening surface is formed into a cylinder or frustum of a cone, mounted on a horizontal or near­ horizontal rotating shaft or on revolving rollers. The material to be screened is fed into the interior of the revolving screen.

rinsing

Removal by spraying, usually with water, of fine or foreign material present among or adhering to larger particles.

type of weave

The way in which warp and weft wires cross each other.

twilled weave

Weave in which every warp wire crosses alternately above and below every second weft wire and vice versa.

undersize control screen; breakage screen

Screen used for the removal of undesirable undersize from a material.

underflow

That portion of the feed which has passed through the apertures of a screening surface.

undersize

Screened product of a size smaller than a specified size.

vibrating screen

Screen oscillated either by mechanical or by electrical means.

woven wire cloth; wire screen

Screening surface, produced by a wire weaving process or by pres­sure-welding of two layers of parallel wires. The wires form square or rectangular apertures of uniform size. They may be precrimped before weaving.

wire diameter

Diameter of the wire for a woven wire cloth, as meas­ured before weaving.

warp

All wires running length­ wise of the cloth as woven.

weft; shoot

All wires running crosswise of the cloth as woven.

wet screening

Screening with the aid of a liquid, usually in the form of a spray.