Glossary Filters and Fabricated Parts

Agglomerate

Agglomeration of single particles.

Aperture Width (w)

Aperture width, w, is the distance between two adjacent warp or weft wires, measure in the projected plane at the mid-positions.

BMT (-ZZ)-S Broad Mesh Twilled Dutch Weave (Zig-Zag)

Broad Mesh Twilled Dutch Weave (-Zig-Zag):
The weft wires in BMT are not arranged to give a "light-tight" cloth but have a pre-set spacing between each other. Because of this the weft mesh count and therefore the retention varies somewhat over periodic intervals.

BMT ZZ, woven as BMT although with a special sequence, guarantees the highest possible accuracy and regularity of spacing.

Broad Aperture; Oblong Aperture

Broad aperture: The warp wire in broad aperture specifications is usually thinner than the weft wire.

Oblong aperture: With wire cloth specifications made from plain, not crimped warp and weft wires, the warp wire is usually thicker than the weft wire.

Bubble-Point-Test

Measuring method for the non-destructive testing of woven filter cloth and ready made filter inserts. Used to determine the maximum pore size diameter. The sample is fixed in a measuring device and wetted with a test liquid with a defined surface tension until all pores of the filter medium are filled. Pressure is then applied from the non-wetted side until the first air bubble pushes through the mesh against the test liquid. This maximum capillary pressure, the so-called bubble point, is a measure of the equivalent pore size diameter of the filter medium.

> more about the Bubble-Point-Test

Calendering

The woven wire cloth is rolled to a specified thickness, simultaneously producing a smooth surface. For fine mesh, this can also influence the filtration criteria of the cloth.

Certification

Haver & Boecker's quality management system is certified according to DIN EN ISO 9001:2008. The company's automotive area is also certified according to the especially high standards of ISO TS 16949.

Chemical Analysis

Self-developed, proven tests are conducted in our chemical laboratory along with standard corrosion tests (e.g. ASTM 262, G28 and others) and compared with customer test processes. This is accompanied by corresponding documentation and the monitoring of all cleaning media and cleaning results.

Residual contamination analyses related to the guidelines of VDA 19 assures our processes.

Crimping

Accumulative curvature on a wire as a result of pre-deformation or weaving.

DTW-S Dutch Twilled Weave

Dutch Twilled Weave:
The weft wires in a twill weave are laid together as closely as possible, whereby one weft wire lies above and the next below the warp wire in each case. DTW cloth can also ve woven with multiple warp wire layers, to increase the micron retention.

Geometrie Pore Size

Compared to other filter media, the specific properties of a woven wire mesh may be precisely described geometrically and defined by the type of weave, wire diameter and mesh counts. This is a considerable advantage because the geometric pore size and permeability can be precisely calculated without the need for exhaustive measuring methods. A characteristic value is determined for the geometric pore and describes the diameter of a round sphere that is just able to pass through the wire mesh.

Glass Bead Test

Measuring method for the characterisation of filter media: The glass bead test is based on the classical screening process. Glass beads with a sphericity of almost 1 and a known size distribution are added to the filter medium and screened. The particle passage is evaluated using the maximum particle diameter.

HIFLO-S High Flow Filter Weave

High Flow Filter Weave:

The weft wires which are very thin in relation to the warp and laid as close as possible against each other in a plain weave. Because of this the free flow cross section is significantly increased compared to other types of weave.

Inspection certificate 3.1

Upon customer's request we supply an inspection certificate 3.1 according EN 10204. It certifies the measurement results for the average aperture sizes and wire diameters, measured in warp and weft direction of the woven wire cloth.

ISO 9001:2008

DIN EN ISO 9001:2008 specifies the requirements for a quality management system (QMS). A certification process provides proof of compliance.

Haver & Boecker was one of the first companies to be certified according to DIN EN ISO 9001 as early as 1997.

ISO TS 16949

The Haver & Boecker automotive area is certified according to the especially high standrafs of ISO TS 16949. 

Oblong Aperture; Broad Aperture

Oblong aperture: With wire cloth specifications made from plain, not crimped warp and weft wires, the warp wire is usually thicker than the weft wire.

Broad aperture: The warp wire in broad aperture specifications is usually thinner than the weft wire.

Mesh Count

The number of apertures in a woven wire cloth per English inch = 25.4 mm

Micron Retention

The diameter of the largest spheric particle that is just able to pass through the filter medium.

> more about micron retention 

MINIMESH® S-Filter Cloth

MINIMESH® metal filter cloth from Haver & Boecker has been used as filtration media for over 100 years. The new generation of MINIMESH® S can be tailored precisely to the individual needs of the application. Without the need for expensive measurement equipment, the geometric pore size and permeability can be calculated precisely in advance.

> more about MINIMESH® S-Filter Cloth

Number of Apertures per Unit Length (n)

The number of apertures which are counted in a row one behind the other for a given unit length. The unit length may be 1 cm, 1 dm, Inch or any other unit of length. 

The number of apertures with a length of 25.4 mm is designated as "Mesh".

Open Screening Area, Ao

The percentage of the area of all the apertures in the total screening surface or the ratio of square of the nominal aperture size w and the square of the nominal pitch p (=w + d), rounded to a full percentage value.

Physical Analysis

Provides information about the mechanical characteristics of the wire. Testing methods include tensile strength and pressure testing.

Pitch (p)

The distance between the middle point of two adjacent wires or the sum of the aperture size w and the wire diameter d.

Plain Weave

Weave in which every warp wire crocces alternately above and below every wert wire and vicd versa.

Plain Weave

Type of weave wherein each warp wire alternately crosses over and under each weft wire.

Pleating

The metal wire cloth is pleated in order to enlarge the filter surface. The pleat geometry and – for multi-layer media – the layer structure are tailored to the filtration process.

Police Filter

Emergency filter that protects an active system against mechanical damage by foreign objects.

Pressure Drop

When a fluid flows through a filter medium, a pressure difference is generated between the inlet and outlet sides. This is dependent upon the geometry of the filter, the load and the properties of the fluid. Haver & Boecker specifies the value zeta as a parroter for evaluating the permeability for fixed flow data.

RPD-S Revers Plain Dutch Weave

Reverse Plain Dutch Weave:
RPD has warp wires laid as close as possible one to another with relatively thin diameters, while the weft wires are very strong.

RPD HIFLO-S High Performance Metal Filter Cloth

This three-dimensional weave technology offers filtration properties that have not yet been attainable with industrial metal wire cloth.

> more about RPD HIFLO-S

Sintering / Annealing

Heat pre-treatment for facilitating further processing of woven wire cloth.

SPW-S Single Plain Dutch Weave

Single Plain Dutch Weave:
The weft wires are plain woven toile as close as possible against each other in a linen weave. SPW-filter cloth can also be woven with multilayer warp wires lying in parallel. This improves the micron retention.

Square Aperture

Warp and weft wires are of almost the same diameter.

TRD-S Twilled Revers Dutch Weave

Twilled Reverse Dutch Weave:
TRD is a Reversed Dutch Twilled type, although in a twilled form. The warp wires are distributed as with RPD, although the weft wires are knocked up in a taille weave patter, so as not to deform the warp wires too much. 

TS 16949

Haver & Boecker's automative area is certified according to the especially high standards of ISO TS 16949.

Twilled Weave

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

Type of Weave

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

Viscosity

Measure of the resistance of liquids and melts.

Warp

All wires running across the cloth as woven.

Weft

All wires running across the cloth as woven.

Wire Diameter (d)

The diameter of the wire in the woven cloth. The wire diameter may be altered slightly during the weaving process.

Zero Aperture

The warp- and weft wires in zero aperture specifications lie as close as possible against each other.


Filters and Fabricated Parts | Phone: +49 (0) 25 22 - 30 522 | Fax: +49 (0) 25 22 - 30 404 | fuf@haverboecker.com
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