Test Sieves Terminology for Sizing and Separation Systems and Processes

Particle size analysis through the use of standard test sieves, and particle separation through the use of screening media, are commonly adopted methods of achieving desired process specifications related to particles. To ensure a better understanding of sizing and separation systems and processes and to ensure appropriate comparison of data, terminology common to the processes must be documented and defined.

Agglomerate, n—two or more particles adhering together.

Aperture, n—the opening in a screening or sieving medium.

Aperture size, n—the dimension defining an opening in a screening or sieving medium.

Bar, n—the metal between perforations.

Blank, n—an unperforated area located other than along the perimeter of a plate.

Bolting grade wire cloth, n—wire cloth meeting a group of specifications that are typical for higher sifting capacities and which can speed the bolting action of vibratory screening machines, manufactured based on using a limited number of wire diameters for a large group of mesh designations.

Break-out, v—a term applied to the action that occurs ahead of the punch in its going through the plate.

Bubble point test, n—capillary flow bubble point methods are based on the fact that the pressure required to force an air bubble through filter cloth wetted under a test liquid of known surface tension is inversely proportional to the pore size.

Bulk density, n—the mass per unit volume of a material, including voids inherent in the material as tested.

Calibration test sieve, n—a test sieve manufactured using sieve cloth which has been inspected after being mounted in the sieve frame, and that meets the requirements in accordance with Specification E11, Table 1, in part based on the standard deviation of the number of sample openings in the test sieve (Column 11) not exceeding the maximum allowable for a confidence level of 99.73% (Column 12).

Centers, n—the dimensional sum of one perforation and one bar, or the dimensional distance from the center of one perforation to the center of an adjacent perforation.

Cloth thickness, n—overall thickness of the filter cloth, nominally estimated by adding the warp wire diameter plus two times the shute wire diameter.

Compliance test sieve, n—a test sieve manufactured using sieve cloth which has been inspected prior to being mounted in the sieve frame, and that meets the requirements in accordance with Specification E11, Table 1, in part based on the standard deviation of the required number of sample openings per 100 square feet of sieve cloth (column 7) not exceeding the maximum allowable for a confidence level of 66% (column 8).

Crimp, n—the corrugation in the warp or shute wire, or both.

Cumulative retained distribution graph, n—a graph obtained by plotting the total (cumulative) percentage by the mass retained on each of a set of sieves versus the corresponding aperture sizes.

Cumulative passing distribution graph, n—a graph obtained by plotting the total (cumulative) percentage by the mass passing each of a set of sieves versus the corresponding aperture sizes.

Die side, n—the surface of the plate that was against the die during the punching operation.

Double crimp wire cloth, n—wire cloth woven with approximately equal corrugations in both the warp and shute wires to lock the wires in position.

Electroformed material, n—electrodeposited grid material consisting of precision openings used as the base material for electroformed sieves.

Electroformed sieves, n—see test sieves (electroformed).

Endpoint, n—point at which no more material falls through the sieve concluding the sieving, taking into account sample degradation.

Filter cake (surface cake), n—material that is retained on the filter cloth during processing.

Finished end pattern, n—the condition that occurs with some specifications of staggered pattern perforations as a result of tool design where the pattern is completed on both ends of the plate.

Firmness, n—a subjective term referring to the planar rigidity of wire cloth (as a roll good, not mounted in a frame).

Flat top wire cloth, n—wire cloth with deep crimps, as in lock crimp, except that all crimps are on the under side of the cloth, leaving the top surface all in one plane.

Gage (also gauge), n—a number designating a specific thickness of metal sheet tabulated in a standardized series, each of which represents a decimal fraction of an inch.

Glass bead test, n—method for determining the filtration rating of filter cloth using a set of presorted precisely sized spherical glass beads, passing them through the filter cloth, and examining the beads passed or captured.

Inspection test sieve, n—a test sieve manufactured using sieve cloth which has been inspected after being mounted in the sieve frame, and that meets the requirements in accordance with Specification E11, Table 1, in part based on the standard deviation of the required number of sample openings in the test sieve (Column 9) not exceeding the maximum allowable for a confidence level of 99% (Column 10).

Intermediate crimp wire cloth, n—precrimped wire cloth with extra crimps or corrugations between the points of intersection.

Lock crimp wire cloth, n—precrimped wire cloth with deep crimps at the points of intersection to lock the wires securely in place.

Margin or border, n—an unperforated area located along the perimeter of a plate.

Market grade wire cloth, n—wire cloth meeting a group of specifications that are typical for use in the general industrial market, manufactured based on using a different wire diameter for each of the common mesh designations.

Matched test sieve, n—a test sieve that reproduces the performance results of another test sieve within user defined limits for a designated material.

Median particle size, n—the particle size at which half the distribution (by mass, volume, number, etc.) is larger than and half smaller than the stated size.

Mesh, n—the number of wires or openings per linear inch (25.4 mm), counted from the center of any wire to a point exactly one inch (25.4 mm) distant, including the fractional distance between either thereof.

Micron, n—common filtration reference to a particle size, properly defined as a micrometre.

Micron retention, n—separation particle size of the filter cloth expressed as a diameter in micrometres.

Micron retention, absolute, n—diameter of the largest spherical particle that will pass through the filter cloth under laboratory conditions representing the maximum pore size.

Micron retention, nominal, n—subject to user definition, an indication of the average pore size of the filter cloth.

Mill grade wire cloth, n—wire cloth meeting a group of specifications that are typical for milling grain and other light screening, manufactured based on using a different wire diameter for each of the common mesh designations.

Near size particle, n—a particle of a size approximately equal to the aperture size of the sieve that may block an opening.

Non standard frames (electroformed), n—sieve frames other than as specified in accordance with Table 2 of Specification E161 that may be circular, square, rectangular, or non-metal.

Non standard frames (wire cloth), n—sieve frames other than as specified in accordance with Table 2 of Specification E11 that may be circular, square, rectangular, or non-metal.

Pan (also collection pan), n—a device that collects all of the material that has passed the sieving process, typically used on the bottom of the sieve stack.

Particle size analysis, n—the process by which the particle size distribution is determined.

Particle size distribution, n—in sieve analysis, the percentages, by mass or number, of all fractions into which various sizes of particles are classified.

Percent open area, n—the ratio of the area of the openings to the total area expressed as a percentage.

Percent passing, n—mass fraction percentage of material that passes through the sieve after the test has been performed.

Percent retained, n—mass fraction percentage of material that is left upon or retained by the sieve after the test has been performed.

Perforated pattern, n—the pattern that the perforations are arranged in, usually in a staggered pattern with midpoints nominally at the vertices of isosceles triangles or square patterns arranged in line with their midpoints nominally at the vertices of squares.

Plain weave, n—see types of weaves, plain.

Precrimp, n—wire cloth woven with both the warp and shute wires crimped before weaving.

Rectangular (off-count) mesh, n—Either precrimp or double crimp wire cloth having a different number of wires in the warp and shute, producing rectangular openings; the diameter of the warp and shute wires may be the same or different.

Representative sample, n—a sample taken from a quantity of material that exhibits the characteristics of the original material from which it was taken.

Screen, n—(1) surface provided with apertures of uniform size and shape; (2) another term used interchangeably for woven wire cloth; (3) a machine provided with one or more screen surfaces.

Screening, v—process of separating a mixture of different sizes by means of one or more screen surfaces.

Selvage, n—the edge or border of wire cloth finished off so as to prevent unraveling; examples of finished edges include looped selvage, folded selvage, cut and tucked, welded, plastic bonded, and bent-back picket, as opposed to a raw or cut edge.

Shute wires, n—the wires running the short way of, or across the cloth as woven (also referred to as the shoot, fill, or weft wires).

Sieve, n—an apparatus consisting of a media with regularly spaced apertures of uniform size, mounted in a suitable frame or holder, for use in separating material according to size.

Sieve analysis, n—the act of obtaining a particle size distribution using test sieves.

Sieve cloth, n—woven wire cloth conforming to Specification E11.

Sieve shaker, n—the mechanical device or method used to shake the sieves, excluding hand sieving.

Sleaziness, n—wire cloth that does not exhibit firmness.

Smooth side or punch side, n—the surface of the plate that was the uppermost during the punching operation and through which the punch entered the plate.

Space cloth, n—wire cloth that is designated by the width of the open spaces between the inside faces of adjacent parallel wires, expressed in inches or the metric equivalent.

Square mesh, n—wire cloth having the same number of wires in both the warp and shute.

Support grid, n—conductive metal grid mounted to the sieve sheet.

Test sample, n—a quantity of material required for use directly in a testing procedure.

Test sieve (electroformed), n—a sieve manufactured by mounting electroformed material consisting of high precision openings in a frame, designed for use in particle size analysis by sieving.

Test sieve (perforated plate), n—a sieve manufactured by mounting perforated plate in a frame, designed for use in particle size analysis by sieving.

Test sieve (wire cloth), n—a sieve manufactured by mounting sieve cloth in a frame, designed for use in particle size analysis by sieving.

Triple shute, n—wire cloth woven with three shute wires inserted adjacent to each other, often constructed in conformance with precrimp rectangular.

Twill weave, n—see types of weaves, twill.

Types of weaves—

• Double warp, n—filter cloth (either plain or twill) in which two warp wires are used instead of one for each warp pitch thus reducing the micron retention of a similar regular single-warp wire specification.
• Herringbone twill, n—wire cloth in which the direction of a twilled weave is reversed at regular intervals to produce a striped or herringbone effect.
• Plain, n—wire cloth in which the warp wires and shute wires pass over one and under one wire in both directions.
• Reverse weave, n—filter cloth in which the warp and shute wires are woven in a reverse configuration; not covered within Guide E2814.
• Twill, n—wire cloth in which the warp wires and shute wires pass over two and under two wires in both directions.

Unfinished end pattern, n—the condition that occurs with some specifications of staggered pattern perforations as a result of tool design.

Warp wires, n—the wires running the long way of the cloth as woven.

Weight per unit area, n—the weight per square foot for wire cloth can be approximated.

Width opening, n—distance between two parallel adjacent warp or shute wires, measured in the projected plane.