ASTM E2814-11
(Guide)Standard Guide for Industrial Woven Wire Filter Cloth
Standard Guide for Industrial Woven Wire Filter Cloth
ABSTRACT
E2814 covers the special grade of industrial woven wire cloth, referred to as filter cloth, for general filtration including the separation of solids from fluids (liquids or gases).
Filter cloth can be made of any primary metal or metal alloy wire that is suitable for weaving. There was no existing standard for filter cloth, which is a widely used material in industrial filtration.
The purpose of the guide is to introduce standard terms and definitions, observe common technical considerations that a user should be aware of, and to present a mathematical model that can be used to predict the micron retention or separation particle size of any filter cloth specification a user and producer wish to develop.
SIGNIFICANCE AND USE
Industrial filter cloth is a specialized product that can be manufactured in many specifications. The purpose of this guide is to (1) introduce standard terms and definitions associated with wire filter cloth, (2) observe common technical considerations that a user should be aware of, and (3) present a mathematical model that can be used to predict the micron retention of a filter cloth specification. As often numerous specifications may be developed to result in a common micron retention by varying the weave type, mesh count, and wire diameters, it is recommended that the user consult with their filter cloth supplier regarding specific filter cloth specifications of interest and include in their discussions durability, pressure drop, and cleaning capability requirements. The purpose of this guide is not to suggest a limited selection of specifications.
The micron retention of a filter cloth specification can be mathematically modeled as well as determined by the use of a glass bead test or the bubble-point test method or both depending on the degree of fineness. Typical standard bubble-point test methods (porometry) include Test Methods F316 and SAE ARP901.
SCOPE
1.1 This guide covers the special grade of industrial woven wire cloth, referred to as filter cloth, for general filtration including the separation of solids from fluids (liquids or gases), based on a desired particle size retention. Filter cloth can be made of any primary metal or metal alloy wire that is suitable for weaving.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E2814 − 11
Standard Guide for
Industrial Woven Wire Filter Cloth
This standard is issued under the fixed designation E2814; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Industrial metal filter cloth is a special type of woven wire cloth that can be produced in many
specifications,oftenproprietaryinnature.SometimesreferredtoasDutchweaveorHollanderweave,
filter cloth can be woven in a variety of metals and is woven with a greater number of wires in one
directionthantheother,andutilizingtwodifferentwirediameters.Thisguidecoverswovenwirefilter
cloth for industrial use, which is commonly rated by its micron retention capability. Its purpose is to
introduce standard terms and definitions, to observe common technical considerations that a user
should be aware of, and to present a mathematical model that can be used to predict the micron
retentionofafilterclothspecification.Itshouldbenotedthisguideexcludesstandardindustrialwoven
wireclothandsieveclothfromitsscope,sincethesearecoveredunderSpecificationsE2016andE11,
respectively, as well as excludes plastic and synthetic filter cloth.
1. Scope 2. Referenced Documents
1.1 This guide covers the special grade of industrial woven 2.1 ASTM Standards:
wire cloth, referred to as filter cloth, for general filtration E11Specification forWovenWireTest Sieve Cloth andTest
includingtheseparationofsolidsfromfluids(liquidsorgases), Sieves
based on a desired particle size retention. Filter cloth can be E1638Terminology Relating to Sieves, Sieving Methods,
made of any primary metal or metal alloy wire that is suitable and Screening Media
for weaving. E2016Specification for Industrial Woven Wire Cloth
F316Test Methods for Pore Size Characteristics of Mem-
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
brane Filters by Bubble Point and Mean Flow Pore Test
as standard. The values given in parentheses are mathematical
2.2 SAE Standards:
conversions to SI units that are provided for information only
ARP901Bubble-Point Test Method
and are not considered standard.
1.3 This standard does not purport to address all of the 3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 For additional terminology, refer to Terminology
priate safety and health practices and determine the applica-
E1638.
bility of regulatory limitations prior to use.
3.1.2 bubble point test, n—capillary flow bubble point
1.4 This international standard was developed in accor-
methods are based on the fact that the pressure required to
dance with internationally recognized principles on standard-
force an air bubble through filter cloth wetted under a test
ization established in the Decision on Principles for the
liquidofknownsurfacetensionisinverselyproportionaltothe
Development of International Standards, Guides and Recom-
pore size.
mendations issued by the World Trade Organization Technical
3.1.2.1 Discussion—The pressure observed at the first
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This guide is under the jurisdiction of ASTM Committee E29 on Particle and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Spray Characterization and is the direct responsibility of Subcommittee E29.01 on Standards volume information, refer to the standard’s Document Summary page on
Sieves, Sieving Methods, and Screening Media. the ASTM website.
Current edition approved April 1, 2011. Published July 2011. DOI: 10.1520/
AvailablefromSAEInternational(SAE),400CommonwealthDr.,Warrendale,
E2814-11.
PA 15096-0001, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2814 − 11
bubble location is considered the absolute micron retention tration of contaminant, and the buildup of filter cake, such that
rating (see Test Method F316). 94% to 98% of all particles of the nominal value will be
retained after a given working period.
3.1.3 cloth thickness, n—overallthicknessofthefiltercloth,
nominally estimated by adding the warp wire diameter plus
3.1.12 percent open area, n—because of the irregular
two times the shute wire diameter.
triangular-shaped opening formed at an angle to the plane of
3.1.4 crimp, n—corrugation in the warp and shute wires.
the filter cloth surface, the percent open area is generally not a
3.1.4.1 Discussion—The crimp in the wires is formed dur-
specified parameter.
ing the weaving process, and the tension existing between the
3.1.13 shute wires, n—wires running the short way of, or
warp and shute wires fundamentally determines the respective
across the cloth, as woven (also referred to as the shoot, fill, or
amount or depth of crimp, which in part establishes the
weft wires).
firmness of the filter cloth. With the exception of reverse filter
cloth, the warp wire is tensioned such that it only crimps
3.1.14 types of weaves, n—
minimally if at all, and the shute wire crimps predominately
3.1.14.1 double warp, adj—filtercloth(eitherplainortwill)
around the warp wire.
in which two warp wires are used instead of one for each warp
3.1.5 filter cake (surface cake), n—material that is retained
pitch thus reducing the micron retention of a similar regular
on the filter cloth during processing.
single-warp wire specification (see Fig. 1).
3.1.5.1 Discussion—The filter cake forms and builds up as
3.1.14.2 plain, adj—filter cloth in which the shute wires
particulateisretained,untiltheincreasedflowresistanceofthe
pass over one and under one warp wire (see Fig. 2).
filtercakerequiresitberemovedfromthefiltercloth,typically
by backflushing. The deposition of material forming the filter
3.1.14.3 reverse weave, adj—filter cloth in which the warp
cake can aid in filtration by providing depth filtration, which
and shute wires are woven in a reverse configuration; not
results in a lower micron retention.
covered within this guide (see Fig. 3).
3.1.6 glass bead test, n—method for determining the filtra-
3.1.14.4 twill, adj—filterclothinwhichtheshutewirespass
tionratingoffilterclothusingasetofpresortedpreciselysized
over two and under two wires (see Fig. 4).
sphericalglassbeads,passingthemthroughthefiltercloth,and
3.1.15 warp wires, n—thewiresrunningthelongwayofthe
examining the beads passed or captured.
cloth as woven.
3.1.6.1 Discussion—The largest bead passed is considered
the absolute micron retention rating.
3.1.16 weight per unit area, n—weight per square foot for
3.1.7 mesh, n—number of wires or openings per linear inch filter cloth can be approximated (without consideration for the
or 25.4mm counted from the center of any wire to a point
significant crimp of the shute wire) by the following equation:
exactly 1in. or 25.4mm distant, including the fractional
2 2 2
Wt/ft 5 @12M ~12π ~D /4! ρ!#1@12M ~12π ~D /4! ρ!# (1)
w w s s
distance between either thereof.
where:
3.1.8 micron, n—common filtration reference to a particle
Wt/ft = weight (lb) per square foot,
size, properly defined as a micrometre.
M = mesh warp,
w
3.1.9 micron retention, n—separation particle size of the
M = mesh shute,
s
filter cloth expressed as a diameter in micrometres.
D = diameter warp wire,
w
3.1.10 micron retention, absolute, n—diameterofthelargest
D = diameter shute wire,
s
spherical particle that will pass through the filter cloth under ρ = density of material (lb/in. ) (0.2836 for stainless
laboratory conditions representing the maximum pore size. steel 304),
π = constant 3.1416.
3.1.11 micron retention, nominal, n—subject to user
definition, an indication of the average pore size of the filter
3.1.16.1 Discussion—Thetheoreticalmassperunitareacan
cloth.
be similarly calculated with SI units or an approximate
3.1.11.1 Discussion—The nominal rating may refer to: (1)
multiplier factor of 4.8824 can be used to obtain kilograms per
theglassbeadorparticlesizethefilterclothwillretain90%of
square metre.
byweight;(2)thebubblepointporesizewhenthetenthbubble
3.1.17 wire diameter, n—wirediametershallbeexpressedin
location appears; or (3) the degree of filtration achieved under
specificprocessconditionssuchasoperatingpressure,concen- decimal parts of an inch or the metric equivalent.
NOTE 1—Reprinted with permission from the Haver & Boecker Woven Wire Cloth Reference Book.
FIG. 1 Double Warp Plain and Double Warp Twill Weave
E2814 − 11
NOTE 1—Reprinted with permission from the Haver & Boecker Woven Wire Cloth Reference Book.
FIG. 2 Plain Weave
NOTE 1—Reprinted with permission from the Haver & Boecker Woven Wire Cloth Reference Book.
FIG. 3 Reverse Plain Weave
NOTE 1—Reprinted with permission from the Haver & Boecker Woven Wire Cloth Reference Book.
FIG. 4 Twill Weave
4. Significance and Use table of common filter specifications stating construction
requirementsandresultingparameters.Instead,amathematical
4.1 Industrialfilterclothisaspecializedproductthatcanbe
model is presented that can be used to predict the micron
manufacturedinmanyspecifications.Thepurposeofthisguide
retention or separation particle size of any filter cloth specifi-
is to (1) introduce standard terms and definitions associated
cation a user and producer wish to develop.
with wire filter cloth, (2) observe common technical consider-
ations that a user should be aware of, and (3) present a 5.2 This mathematical model is presented by Reiner Tittel
mathematical model that can be used to predict the micron andRolfBerndt withfurtherconclusionsbyDenisBlackmore
retention of a filter cloth specification. As often numerous (see Appendix X1). The model assumes rigid, spherical par-
specifications may be developed to result in a common micron ticles that pass through various planes or cross sections of the
retention by varying the weave type, mesh count, and wire filter cloth created by shute wires stretched around warp wires
diameters, it is recommended that the user consult with their and positioned geometrically adjacent to one another. The
filter cloth supplier regarding specific filter cloth specifications separation particle size is determined for the applicable geo-
of interest and include in their discussions durability, pressure metric plane based on the weave type and specification ratios.
drop,andcleaningcapabilityrequirements.Thepurposeofthis
5.3 While five geometric planes of the filter cloth are
guide is not to suggest a limited selection of specifications.
considered (three of interest as the outer two are symmetrical),
4.2 Themicronretentionofafilterclothspecificationcanbe Plane3, designated the geometric middle plane of the filter
mathematically modeled as well as determined by the use of a cloth, is the primary plane of interest. Accordingly, the sepa-
glass bead test or the bubble-point test method or both ration particle size (dTr ) is determined for plain weave with
depending on the degree of fineness. Typical standard bubble- warp wire to shute wire diameter ratios within the range 1.00
pointtestmethods(porometry)includeTestMethodsF316and to 1.50 (see Annex A1). For twill weave with warp pitch to
SAE ARP901. warp wire diameter ratios greater than 3.22, Plane2 is consid-
ered and the separation particle size (dTr ) is determined. For
5. Filter Cloth Specifications
the calculation of dTr , Blackmore concludes that for the
equatedTittelandBerndtequations,thecoordinateoriginratio
5.1 Filter cloth is woven in a variation of sometimes
(t/t )andthegeometricdimension(x)canbothbeexpressedas
proprietary parameters based on often common nominal mesh 1
a function of the warp-to-shute-wire diameters (b) (see Annex
count specifications. This is due to minor variations in mesh
A2).Themodelisnotapplicableforreverseweavefiltercloth.
count and wire diameters used to affect micron retention,
porosity, and other factors related to specific operating
conditions,aswellaspossiblyformanufacturingconvenience.
Tittel, R. and Berndt, R., “Zur bestimmung der trennteilchengr ße von
Therefore, it is not appropriate to provide a comprehensive filtergeweben,” Faserforschung und Textiltechnik, Vol 24, 1973, pp. 505–510.
E2814 − 11
5.4 A selection of typical woven wire filter cloth specifica- material, the relationship of the mesh to wire diameters, the
tions are presented with their particle size retentions as type of weave, the amount of crimp in the wires, and the
determined by theTittel and Berndt model in conjunction with tension on the warp wires during the weaving. The absence of
the Blackmore conclusions (see Appendix X2). These specifi- firmnessinwovenwirefilterclothistermedsleaziness.Woven
cations are only for example, as countless others may be wire filter cloth should normally exhibit satisfactory firmness;
considered for weaving. Check with a weaver to determine the that may be discussed with the supplier.
feasibility of others. Note that the physical properties of the 6.4.8 Wovenfilterclothmaybecoveredwithafilmofoilor
wire to be woven may have an impact on overall filter cloth other lubricant as a result of the manufacturing process. The
quality. wire may show traces of products used in or markings caused
by the drawing process.
6. Technical Considerations
6.4.9 Thetolerancesthatcanbeheldoncut-to-sizepiecesof
6.1 Wire Tolerances—The diameter tolerance for wire be-
filter cloth can be dependent on the piece size, the mesh, wire
fore weaving commonly should be in accordance with indus-
diameters, type of weave, and firmness of the weave. These
trial standards. It is recognized that mechanical deformation of
factors should be considered in the discussion of tolerances
particularly the shute wire occurs during weaving. Therefore,
with the supplier.
the diameter measured after weaving can only be used as a
7. Procedure
guide to the original nominal diameter.
7.1 Filterclothisbestinspectedusingabacklighttoobserve
6.2 Filter Cloth Tolerances:
irregular and defective openings.
6.2.1 Industrial filter cloth can be woven from a great
variety of metals and alloys. Metals other than 300 series
7.2 The mesh count of filter cloth may be checked using a
stainless steel may not be possible depending on the particular
counting glass compatible with the degree of fineness.All test
specification and should be discussed with the supplier.
apparatus should be calibrated against standards traceable to
6.2.2 Tolerances on parameters such as mesh count and
the National Institute of Standards and Technology.
micron retention shou
...
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