Glossary

This is the rate of change to speed, in most cases of the vibrations. This exerts a force on the moving mass, i.e. the screen and particles.

This is a fine particle adhering to coarse material or the screening fabric.

This is a test screen for very fine material.

This clogs the screening surface, in most cases under the action of moisture, more rarely under adhesive forces or electrostatic buildup.

This is the angle the screen forms with the horizontal.

A large number of clumped particles.

The distance a screen moves through from its highest to its centre point. The amplitude equals half of the distance between the movement’s highest and lowest point. See also Throw. The amplitude of a linear vibration is half of the total distance, that of an ellipsoidal vibration half of the ellipsis’s major axis.

These exhibit defined mesh apertures serving to determine the distribution of particle sizes.

This is a measure of the aperture in a screen panel.

Wide meshed screening fabric that protects the fine meshed layers.

This is the deck under the screening area that holds the cleaning balls (e.g. of rubber).

This is the vertical depth of the product on the screening deck and is usually 3–4 times the mesh aperture.

This is the liquid bound hygroscopically in an input product sample, usually specified as a mass fraction of the sample in percent.

This is the weight per unit volume of loose material, applied normally to loose or powdery material with air inclusions and specified in kg/m³.

This is the solid fraction of a suspension specified in percentage by weight or volume.

This is the screen defining the largest particle size.

The input material runs down the screen inclination, and not in the direction of the upward conveying vibrations. This loosens up thoroughly the input material.

This is the speed at which the material is conveyed under vibration and/or the angle of inclination.

The input material keeps circulating e.g. in the comminution–screening circuit until it reaches the required fineness.

This is when the drive speed equals the natural frequency of a spring-mass system, in most cases an undesirable state.

This is a method of depicting particle size distributions.

A series of bends worked into a wire by preforming or weaving.

This is material that adheres to and blocks the apertures in a screening fabric.

A general term for unwanted fine and coarse material

Deck or screening deck: That part of the screening machine bearing the screen linings.

This is the time a particle remains on the screen surface.

The separation of clumped particles.

Removal of very fine particles from the input material.

This is the product quantity yielded by a treatment process, specifically the end product of a process cycle (e.g. screening yield or finished product).

Screening fabric with crimped warp and shute wires.

This is used to separate material that exhibits no surface moisture, hence no adhesive forces induced by surface tension.

This is the ratio of undersized to oversized product weight (mass) expressed as a percentage.

This is that part of the screening deck available for separating the input material.

This is a screening machine moved by electromagnets.

This is a screening machine that executes elliptical screening movements.

This is a resonating vibrator.

The eccentric and a linkage translates rotary movement into a linear stroke.

This is an element of an unbalanced motor mounted on two eccentric bearings, hubs, or bushes.

The maximum distance of a circular vibration from the centre (equalling the circle’s radius).

This is the quantity a screening machine can process. It is the product of screen area in m² and the specific screening capacity in t/m²h.

These are particles smaller than a defined size. These are sometimes equated with the screenings (not recommended).

Overloading in a screening machine.

This screening machine prevents coarse particles from entering the downstream screener, thus eliminating potential disruption to operations.

The number of highest and lowest points that a screening machine passes in one second, measured in hertz (Hz).

This is the acceleration due to gravity, g = 9.81 m/s². The vibrational acceleration is often specified as a multiple of g, e.g. 1.5–6.6 g.

This screening machine vibrates vertically at a speed of over 600 rpm and through a distance less than 2.5 cm.

These are the heaviest goods during jigging.

This is the accelerating force generated by the screening machine, usually three to seven times the acceleration due to gravity (3–7 g).

This is liquid, in most cases water, that is retained in the interstices between particles.

Vibrating screen inclined at an angle of usually 10–45°.

This screen vibrates over a distance defined by the forces exerted by an unbalanced mass.

This is the size of the oblong or square openings in the screen lining through which the product passes.

This is the number of apertures per unit length in a wire screen fabric.

This is the depth (thickness) of the input material running over the screening surface.

This is a series of screening decks that are arranged in parallel under each other and that are intended to output multiple fractions in the one screening machine.

This is the number of screen apertures per inch. This is the US measure for mesh aperture. It is inexact because it does not include the wire gauge.

The weighted, averaged particle size in a sample, quantity, or batch of input material.

This is the input particle size corresponding to about 90–110% of the mesh aperture. These particles can be screened with difficulty only. It is also a measure of the screening capacity.

Elongated aperture in the screening fabric or perforated plate. This is usually the ratio 1:3 or 1:10.

This is a wire screen panel featuring apertures that are longer than wide or vice versa.

Oversize, undersize, or both in the product. This is specified as a percentage of the product quantity.

For wire screen panels: This is the ratio of the total mesh aperture area to the whole screen area expressed as a percentage. For perforated plates: This is the ratio of the total area of all holes to the total area of the perforated section of a plate expressed as a percentage.

This is the ratio of screen aperture area to screen panel area.

This is the screened percentage of the input product, used to determine the screening efficiency.

This is that part of the input material that did not or cannot pass through the apertures in the screen panel.

This is reject material following treatment.

This is a single constituent of matter of any size.

This is the rated width of the smallest aperture in a screen panel through which a single particle can pass.

This is returned by a laboratory analysis on a product that has been passed through a large number of different mesh sizes and whose various weight fractions have been plotted as accumulative percentages on a graph.

This separates out a small part of the input material, generally undesirable oversizes.

In this weave, every warp wire passes alternately over and under every shute wire and vice versa.

This is a plate perforated with holes of various shapes. The apertures can be oblong, slotted, round, or of another symmetrical shape.

This uses shaft eccentricity to define the throw.

This is the ratio of the number of OK particles in the product fraction to its total quantity. It is often used to specify the product quality.

This removes a small quantity of oversize (coarse contaminants) from the input material. A typical oversize fraction is less than 5%; at least 50% is smaller than half of the mesh width.

This is the particle size describing the discharged material.

The exciting frequency that sets the spring-mass system vibrating at its natural frequency.

This is the separation of particulate material into defined particle sizes.

This is the angle at which a level surface must be inclined before the input material starts slipping under static conditions.

This is the separation of the coarse oversize fraction from the input material. These are 50% larger in diameter or width than the largest particle in the screened material. Their quantity is normally 10–20% of the input material.

This is the range between two defined particle size limits in the input material.

This is the representational division of the initial quantity until the quantity for analysis has been reached.

This is the proportion of material that has passed through the screening medium, including contaminants and foreign particles.

This is the liquid that has passed through the screen.

This is the woven edge of the screening fabric.

This is the content of solid matter in a suspension. This is specified in most cases as a percentage by weight or volume.

This is a screening machine that excites directly the screen lining at 50 or 60 Hz (in the audible range).

This is the liquid adhering to the exposed surface of the particles in a sample. This is usually specified as the mass fraction of the sample in percent.

This forms in a material bed when the effect of vibrations causes the finer material to migrate downwards and the coarser material upwards in the product bed.

In this process, the shaking or vibrations cause the coarser particles to move to the surface of the product bed while the smaller particles slip through the gaps to the base of the bed.

These wires traverse at 90° to the screen’s longitudinal axis.

This returns the fractions of particle sizes in the total quantity.

This is the quantity of input material that passes through the screen panel.

This is the material that is fitted to the screening deck, synonymous with screening medium.

The capacity of a screen for a particular task. Specifications without reference to the input material or separation accuracy are worthless.

This sizes a particulate mixture for industrial purposes. “screen” is also short for “screening surface” and “screen deck”.

Standardised screen cascade.

These are that part of the input material that leaves the screen panel without first passing through the screen apertures.

This is the ratio of screened fine material to the total fine material in the input quantity: n = mff/mf0.

This is the increase to a convex screen panel.

This screen panel consists of equally spaced wires of wedge shaped or trapezoidal cross section. The fine material then passes through apertures of increasing cross section.

This is a mixture of liquid and solid matter.

This is the weight per unit volume of the suspension flow, a combination of its solid and liquid density, calculated as a function of the ratio of the solid to liquid weight fraction in the suspension.

The particle size above and below which the over- and undersizes are equal. This is the target of separation.

This is a heavy screening machine with fixed or moving gratings and round or specially designed discs or rollers. It is normally used for separating out relatively large chunks, e.g. larger than 100 mm.

This is the tension in a screening fabric transverse to the direction of the conveyed material.

This is a circular screen frame fitted with a taut screening fabric of standardised size.

In this weave type, every warp wire passes alternately over and under more than one shute wire and vice versa.

The distance between the two furthest positions of a screening cycle. The throw equals twice the amplitude.

This screen executes circular with superimposed tumbling movements.

The flow of input material that runs over the screen surface.

This is excited at frequencies greater than 18 kHz.

This is a particle that is smaller than the mesh aperture over at least one axis.

This rotates to induce movements in a vibrating screen.

This is also called shaker screen or gyratory screen. It is a sizing machine.

This screening type uses a liquid that is generally supplied from shower heads.

The warp wires run along the length of the screening fabric.

All wires in the screen panel running parallel to the weave.

This describes the way the warp and shute wires cross each other.

This is the diameter of a (screen) wire in the screen panel, measured prior to weaving.

This is a screen panel consisting of two layers of parallel wires woven or pressure welded together. The wires form equally sized square or oblong apertures that can be crimped prior to weaving.