Absolute Micron Retention - In both types of Dutch Weave, the sum derived from multiplying the number of weft wires in a given measurement by their diameter, results, in theory, in a specification with no open space. Because the wires are driven together during the weaving process, the aperture size cannot be calculated in the normal manner. There are two methods by which the aperture size can be determined: bubble point testing and glass bead testing.
Angle Insert - Steel (or Stainless Steel) angular shape welded or otherwise fastened to a screen’s formed tensioning hook for reinforcing purposes.
Anneal - A heat-treating process in which the steel is heated to an elevated temperature—usually at or near the critical range—and held at this temperature for a period of time, after which it is cooled at a slow rate. Annealing is employed (1) to soften steel for secondary machining or forming processes; (2) to alter ductility, toughness, electrical or magnetic characteristics or other physical properties; (3) to refine the crystal structure; (4) to produce grain reorientation; or (5) to relieve stresses and hardness resulting from weaving (cold working).
Annealed After - Wire cloth or wire mesh that is annealed after the weaving process.
Anneal Wire - Wire that has been cold-drawn to reduce its diameter is often annealed to reduce strength and increase elongation to facilitate weaving.
ANSI - American National Standards Institute
Aperture - The clear opening between wires or a wire mesh screening surface.
API - American Petroleum Institute
ASME - American Society of Mechanical Engineers
ASTM - American Society for Testing and Materials
AWCI - American Wire Cloth Institute
A.W.G. - American Standard Wire Gauge
AWS - American Welding Society
Backing Cloth - Wire mesh or wire cloth that is utilized to provide support for a screen surface.
Backing Screen - Wire mesh or wire cloth fabricated with, or otherwise fastened to, the primary screen.
Ball Screen - Wire mesh or wire cloth screen placed below the primary screen surface to retain rubber or steel balls or plastic discs which are set in motion by a vibrating screen deck. Ball screens are utilized to reduce or prevent blinding or plugging.
Bands - The material utilized for screen edge (hook) reinforcing. Bands are available in steel, galvanized steel, and stainless steel.
Bend Test - A test for determining relative ductility of wire that is to be formed, and for determining soundness and toughness of wire. The specimen is usually bent over a specified diameter through a specified angle for a specified number of cycles.
Blinding - Filling in and clogging of the wire mesh openings (apertures) due to particle entrapment of the process material. The wire cloth becomes “blind” to the process flow.
BMT - Abbreviation for “Broad Mesh Twilled Dutch Weave”.
Bolting Cloth - A group of industrial wire cloth specifications, woven in very smooth and durable stainless steel or monel in a plain square mesh pattern. Wire diameter is lighter than mill grade for higher open area. Bolting cloth is used for wet or dry sifting and separating.
Bran Duster Cloth - Plain weave steel wire cloth of medium mesh sizes produced in market grade diameters. Available in roll widths of 24”, 30”, 36” and 48” for use in flour mills.
Broadmesh - Specifications where the warp wire is typically smaller in diameter than the weft wire.
Bubble Point Test - The pressure required to pass air bubbles through the mesh (covered by a test liquid) is measured. The average aperture size is then calculated by taking into account surface tension, liquid density, temperature, and immersion depth.
B.W.G. - Birmingham Wire Gauge
Calendered Wire Cloth - Wire cloth that has been passed through as a set of heavy rollers to reduce the thickness of the cloth or to flatten the wires at weave intersections providing a smooth surface.
Caul Screen - A general specification for woven wire screen panels utilized in the production of Oriented Strand Board (OSB), Particleboard, and Wafer Board.
Clear Opening - The space (aperture) between adjacent parallel wires.
Coarse Mesh - Wire cloth having a mesh count of 30 x 30 or less.
Coin - To stamp wire cloth in order to impart a shape or to compact lit. Wire mesh filter discs are often coined around the edges, locking the wires together to prevent unraveling.
Corrosion - Deterioration of a metal by chemical or electrochemical reaction with its own environment.
Count - The number of openings (apertures) in a lineal inch.
Crimp - A smooth contoured indentation formed into wire providing a locking arrangement for perpendicular wires to stabilize the hole size and shape.
Crown - An arc placed in woven screen cloth to facilitate tensioning across a crowned deck.
Cut-back - Edge preparation (hook strip) that is shorter than the screen cloth to allow a lap-joint of the screen cloth panel in conjunction with a butt-joint of the edge preparation, thus preventing leakage between screen panel sections.
Dewatering - Separation of solids from liquids in which the solids are retained on the screen surface while the liquids pass through the screen (wire mesh or wire cloth) surface.
Dutch Weave - Wire mesh or wire cloth with warp wires larger than the shute wires. Warp wires remain straight while adjacent shute wires slightly overlap, resulting in a dense, strong material with small, irregular, twisting passages that appear triangular in shape when viewing the material diagonally. Dutch Weaves have much lower flow rates and much higher particle retention than plain square weaves.
Electro-galvanized - An electrical plating process that results in a thin, evenly distributed coating of zinc over all exposed carbon steel wire surfaces.
Elongation - In tensile testing, the increase in the gauge length, measured after fracture of the specimen with the gauge length, usually expressed as a percentage of the original gauge length.
End Tension Screen - Edge preparation on a screening surface allowing it to be stretched in the direction of material flow.
Edge Tension Wire Cloth - Typically required for long slotted apertures, wire cloth that is tensioned from one or both ends in the direction of material flow, as opposed to side-to-side tensioning methods.
Feather Edges - Straight wire ends (which are not crimped) protruding around the perimeter of a screen cloth section, all in the same plane.
Ferrous Alloys - Alloys or metals containing iron.
Fill Wires - Wires running across the width or short way of wire cloth as woven.
Filter - Device utilizing filter media for particle retention for clarification of a liquid or gas.
Filter Cloth - Wire or synthetic cloth woven with a greater number of wires in one direction than the other, and utilizing two different wire diameters. Filter cloth is woven in both lain and twill weave patterns and is also referred to as “Dutch Weave”.
Filtration - The process of clarifying a fluid or gaseous liquid by the retention of solid particles.
Fine Mesh - Wire cloth having a mesh count greater than 90 x 90.
Flat Bar Fill - A flat wire bar woven into a triple shoot screen, replacing the middle shute wire, providing additional strength.
Flat Top Weave - A weave with all crimps protruding from the bottom screen surface, replacing the middle shute wire, providing additional strength.
Flooding - In wet screening operations such as washing or dewatering, the effect created when the screen surface is unable to pass fluids through.
Formed Edge - An edge preparation on the screen surface sides parallel to the direction of flow, allowing the screen to be fastened securely to the supporting surface, typically in tension.
Galvanize - To coat iron or steel with zinc, primarily to prevent rust.
Gauge - The measure of wire diameter. The Washburn & Moen Gauge is the standard in the manufacture of wire cloth in North America.
Glass Bead Test - A suspension containing glass beads is passed through the mesh; the diameter of the largest bead passing through is considered as the absolute micron retention.
Hard Wire - Wire which has been drawn down to a smaller diameter after the annealing process, increasing its unit strength and reducing its elongation.
Hardware Cloth - A square mesh, general purpose galvanized-after plain weave wire cloth. Made in one wire size only—one for each of several standard meshes. Hardware Cloth is also available in welded construction.
Heated Deck - A screen surface that is heated by using the screen cloth as the heating element. Stainless steel is the preferred material due to its low conductivity.
Herringbone Twill - Wire cloth in which the direction of a twilled weave is reversed at regular intervals to produce a striped or herringbone effect.
ISO - International Organization for Standardization—a worldwide federation of national standard bodies. ISO 4782 standard governs metal wire for industrial wire screens and woven wire cloth; ISO 9044 standard governs industrial wire cloth.
Mechanical Properties - The properties of a material that reveal its elastic and inelastic behavior where force is applied, thereby indicating its suitability for mechanical applications. For example, modulus of elasticity, tensile strength, elongation, hardness, and fatigue limit.
Medium Mesh - Wire cloth having a mesh count of 30 x 30 to 90 x 90, inclusive.
Mesh - The number of openings and fractional parts of an opening, per lineal inch. Mesh is determined by counting the number of openings from the center of any wire to the center of a parallel wire, one inch in distance. When the point one inch distant form the center of a wire falls between wires within an opening, the mesh count is expressed as a fraction.
Mesh Number - The number of apertures in a length of 25.4 mm (1”). While it is considered an obsolete designation, it is used extensively.
Micron - One micron is equivalent to 0.001 mm or 0.00003937 inches. A unit of measure in the metric system, it is frequently used when referring to the aperture size or particle-retention of filter cloth.
Micron Retention - Micron retention is defined as the diameter of the largest round particles that can pass through a filter.
Nonferrous Alloys - Non-pure metals containing no iron, such as copper, brass, aluminum, etc.
Porosity - The fractional void volume of the mesh.
Pre-crimped Weave - Wire cloth woven with the warp and/or shute wires crimped before weaving.
Profile Wire - Wire that has been drawn into a “wedge” shape (tapered), which becomes progressively narrower from top to bottom.
Profile Screen - A screen panel made up of profile wires with openings that become progressively wider from top to bottom. This increases dewatering efficiency and aids in screening material that might otherwise blind a screen surface.
Reinforced Edges - A formed hook on the tensioning edge of a screen panel that is strengthened with the addition of sheet metal.
Retention - The ability of wire cloth, as a filter medium, to prevent the passage of solids. It is expressed by the diameter, usually in microns, of the largest spherical solid particle that will normally pass through the screening surface.
Ripple Flat Crimp - Wire cloth in which the interlocking crimps are on the underside of the screen in addition to shallow formed crimps that are shaped in a downward angle in relation to the top surface. This provides a surface less resistant to material flow while increasing the hardness of the wire.
Sandwich Screen - The combining of two or more non-identical wire cloth screens into one set of reinforced hooks to form one screen panel. Typically the finer mesh screen is placed above the larger mesh or support screen.
Scalp Weave - Wire cloth in which deep crimps are provided in the wires at points of wire intersections to lock wires securely in place. Typically used for heavy-duty screening. Also known as “arch crimp”, “lock crimp”, and “press lock”.
Scalping - A sizing process, secondary to the grizzly where most of the material is smaller than the screen mesh. Oversized material is rejected and sent back to the secondary crusher for further processing and recycled.
Selvage - The edge or border of wire cloth finished off so as to prevent unraveling. Selvage types include looped, folded, cut and tucked, welded, plastic bonded and bent back picket.
Shielding Cloth - Wire cloth used for shielding radio frequency equipment and rooms. Typically provided in pure copper or brass material.
Shoot Wires - The wires running across the cloth as woven. Also referred to as “shute”, “fill”, or “weft” wires.
Side Tension - Edge preparation on a screen surface allowing it to be stretched at right angles to the direction of material flow.
Sieve - Metric openings, in a fixed ratio, assigned by the U.S. Bureau of Standards, based upon the number 18 sieve having an opening of one millimeter (0.039370”). The relation of consecutive numbered sieves is as one to the fourth root of two (or for every fourth sieve ratio is as one to two). Sieve numbers are arbitrary numbers and have no direct relationship to the number of meshes per inch.
Slotted Openings - Wire cloth with rectangular openings that allow the maximum open area and tends to prevent blinding or plugging of material. The warp mesh-count and wire size are indicated before the shute (weft) mesh-count and wire size.
Space - The actual clear opening or space between the inside edges of two parallel wires
Space Cloth - Square mesh wire cloth which is designated by the width o the open space between two parallel wires.
Spark Arrester - Wire mesh used to retain particles of burning materials.
Split Deck - A screen deck longitudinally divided allowing two individual screen panels to be installed across the width of the deck.
Square Hook - The formed hook on the tensioning edge of a screen panel formed in the shape of a “U” or square, with two right angles.
Square Mesh - Wire cloth with the mesh count and wire diameter the same in both directions.
Strainer Cloth - A plain weave off-count mesh cloth with a high percentage of open area.
Support Screen - A heavy wire mesh utilized to support a finer mesh in filtration or straining.
Tensile Strength - In tensile testing, the ratio of maximum load to original load to original cross-sectional area. Also called “ultimate strength”.
Testing Sieve - Fabricated circular frames available in stainless steel, brass, or plastic fitted with wire mesh woven of brass, phosphorous bronze, or stainless steel, having extremely accurate openings. Sieves are produced according to various standards—in the U.S. typically per ASTM E-11-70. Testing sieves are used for grading, sizing, and testing by research and technical institutions, industrial laboratories, and mining engineers.
Tinned Cloth - Wire cloth woven of wire that has been coated with tin before the weaving process. Tinned cloth is generally available in “mill grade” wire diameters.
Trommel Screen - A screen panel which is rolled to cover a cylinder and typically fastened by bolts, clamps, or straps.
Twill Weave - Woven wire cloth in which each weft wire passes successively over two and under two warp wires and each warp wire passes successively over and under two weft wires.
Twilled Dutch Weave - Each warp and each weft wire passes over and under the next to adjacent complementary wires, as in a normal twill weave, except the warp wires are larger in diameter than the weft wires. This allows a greater mesh count in the weft direction. This weave pattern enables the weft wires to be woven more densely, and much smaller aperture sizes can be achieved.
Warp - The wires running lengthwise during weaving.
Weft - The wires that run across the width of the cloth; also known as “shute” wires.
Wire - A solid wrought product that is long in relation to its cross section, which is square or rectangular with sharp or rounded corners or edges, or is round, a rectangular hexagon, or a regular octagon, and whose diameter or greatest perpendicular distance between parallel faces (except for flattened wire) is less than 0.375 inches.
Wire Cloth - A general term for woven metal fabric.
Yield Strength - The stress at which a material exhibits a specified permanent set.