Filter Media and Media Support

Dexmet MicroGrid® and PolyGrid® Parameter

Advantages of Dexmet® Filter Media Support:

Expanded metal diagram to show SWD, LWD, Pore Size, and Raw Thickness
  • Dexmet offers a wide range of expanded metal foils and can produce rolls up to 1,200mm (48”) in width.
  • Dexmet’s precision expansion process ensures high reproducibility leading to a more consistent final product and lower cost of quality.
  • Dexmet’s expansion process produces more finished product per pound of raw material than perforation. Scrap is also minimized because there is virtually no waste. The expansion process is the preferred choice when your design utilizes expensive, hard to procure materials.
  • Woven material can achieve smaller pore sizes than either expanded or perforated products. However, woven material has a tendency to “unwind” at the edges, which can lead to quality and/or manufacturing problems as well as safety issues. More importantly, the strands can move under dynamic flow conditions changing the geometry of the opening and potentially allowing larger particles to pass through.

PolyGrid® Expanded Polymers for Membrane Support

Separation and purification are key criteria for industries that process water, food & beverages, chemicals, and pharmaceuticals. Dexmet custom manufactures all PolyGrid® materials with a multitude of open area designs with controlled pore sizes to provide a more consistent flow rate for your filter application.

If your filter application has a critical upstream/downstream or cross flow requirement, our Engineering Department will partner with you to develop the optimum design to maximize performance and workability. Whether it’s improving liquid flow rate, air flow, strength, or particle retention, Dexmet can provide a material that will give your design the performance advantage.

Applications

  • Membrane Support
  • Separation and Backing
  • Primary Purification

Advantages

  • Assured Media Integrity & Pleat Spacing Even Under Dynamic Flow
  • Increased Filter Surface Area for Pleated Designs (Capability to Expand Thinner Materials to Achieve a Reduced Overall Thickness)
  • Materials Laminate for Contraction, Co-Expansion, and Flex with Filter Membranes (Material Compatibility with Membranes)

Features

  • Pore Size Starting at 25 Microns (.001”)
  • Base Material Thickness Down to .025mm (.001”)
  • 1300+ Openings/cm²
  • Widths to 610 mm (24”) (Wider Widths May Be Available Depending on Material)

Common Materials

Fluoroplastics:

PTFE, PP, PE, PFEP, PCTFE, PVF, PVDF, PFA and ECTFE

Polyamides:

Nylon 6 and Nylon 6.6, PEEK

Polyolefins:

PE and PP

Polyesters (Thermoplastic):

PET, PETP, PBTP

Polysulfones

Polyvinyls

High Temp Plastics:

PTFE, PEEK, Nylons

Purpose

Filters that are designed to remove fine particulate (less than 0.1 mm) frequently employ non-woven filter media that requires mechanical support within the filter body. The support must provide adequate strength while not significantly reducing the flow of the fluid to be filtered.

Design Considerations

  • Filtration Rating: Particulate passage is controlled by the opening size or “pore” diameter of the media and is designated by a Micron rating. The opening configuration (pore) might be diamond-shaped (expanded), square (woven wire), or round (perforated). Designate the opening according to the particle size required to be separated out of the flow path.
  • Backpressure: Flow backpressure results from the “percent open area” and the degree of particulate build-up on the media surface. Choose a material that will more than withstand the full pressure drop across a blocked surface area.
  • Filter Strength: Ultimate strength is controlled by material selection, thickness, percent open area and pore geometry. Multiple layers of filter material with varied openings can improve flow, purification, and withstant higher backpressures.

Dexmet® PolyGrid® over Alternative Materials

  • Dexmet’s precision expansion process ensures high reproducibility leading to a more consistent final product and lower cost of quality.
  • Dexmet can produce “open” polymer sheets of fluoropolymers (such as Teflon) that resist extrusion.
  • Dexmet’s manufacturing process can achieve typical widths up to 24”. Wider widths may be available for certain materials.
  • Extruded plastic is the most commonly used material for filter media support. Extruded material is generally lower in cost per unit area than expanded plastic. However, some polymers (most notably the fluoropolymers, such as Teflon) resist extrusion. In cases where these resins are required, expanded material is the preferred design choice.
  • Woven material can achieve smaller pore sizes than either expanded or extruded products. However, material selection is very limited and more difficult to fabricate, which can lead to quality and/or manufacturing problems. In addition, the strand can move under flow conditions changing the geometry of the opening and potentially allowing larger particles to pass through.

MicroGrid® Expanded Metals for Membrane Support

If your filter application has a critical upstream/downstream or cross flow requirement, our Engineering Department will partner with you to develop the optimum design to maximize performance and workability. Whether it’s improving liquid flow rate, air flow, strength, or particle retention, Dexmet can provide a material that will give your design the performance advantage.

Applications

  • Internal Core Material: Media Support & Backing
  • Primary Filtration
  • Pre-Filters

Advantages

  • Economical Option to Alternative Materials
  • Uniform Material: One Piece Homogenous Design (Assures media integrity under dynamic flow conditions)
  • Engineered Pore Sizes to Achieve Flow, Pressure Drop, and Collapse Pressure Requirements

Features

  • Pore Size Starting at 25 Microns (.001”)
  • Base Material Thickness Down to .025mm (.001”)
  • 1300+ Openings/cm²
  • Widths to 1200 mm (48”)

Common Materials

Stainless Steel, Aluminum, Nickel Alloys, & Carbon Steel (FE).

Dexmet has the capability to expand all ductile metals.

Purpose

Filters (or pre-filters) that are designed to remove large particulates (over 0.5 mm in diameter) must be made to withstand impact stresses as well as fluid pressure. “Open” (expanded, perforated or woven wire) metal foils are frequently used for this function because they can be easily formed for the specific application.

Design Considerations

  • Filtration Rating: Particulate passage is controlled by the opening size or “pore” diameter of the media and is designated by a Micron rating. The opening configuration (pore) might be diamond-shaped (expanded), square (woven wire), or round (perforated). Designate the opening according to the particle size required to be separated out of the flow path.
  • Backpressure: Flow backpressure results from the “percent open area” and the degree of particulate build-up on the media surface. Choose a material that will more than withstand the full pressure drop across a blocked surface area.
  • Filter Strength: Ultimate strength is controlled by material selection, thickness, percent open area and pore geometry. Multiple layers of filter material with varied openings can improve flow, purification, and withstand higher backpressures.
  • Flow restriction is determined primarily by “percent open area” and secondarily by hole geometry.
  • Resistance to corrosion and/or thermal deformation is controlled primarily by material selection.

Dexmet MicroGrid® over Alternative Materials

  • Dexmet offers a wide range of expanded metal foils and can produce rolls up to 1,200mm (48”) in width.
  • Dexmet’s precision expansion process ensures high reproducibility leading to a more consistent final product and lower cost of quality.
  • Dexmet’s expansion process produces more finished product per pound of raw material than perforation. Scrap is also minimized because there is virtually no waste. The expansion process is the preferred choice when your design utilizes expensive, hard to procure materials.
  • Woven material can achieve smaller pore sizes than either expanded or perforated products. However, woven material has a tendency to “unwind” at the edges, which can lead to quality and/or manufacturing problems as well as safety issues. More importantly, the strands can move under dynamic flow conditions changing the geometry of the opening and potentially allowing larger particles to pass through.

Dexmet expanded metal and plastic is used in filters as both filter media (for coarse particles) and as a support for fine filter media (especially non-woven fabrics). Dexmet can provide a wide variety of metals and geometries to exacting specifications. Our technical support team can help you choose the right material to maximize filter efficacy and lifetime, while reducing internal corrosion and other failure modes.

For more information on filter design, try http://www.engineersedge.com/filtration/filtration_table_content.htm

Below is a chart detailing the range and parameters of various configurations. Dexmet Corporation can create configurations in both PolyGrid® and MicroGrid®. You can order smaller quantities of MicroGrid® in sheet form from McMaster-Carr, click here.

This chart is designed to be a guide to the abilities of our process and is not a complete product list. Our engineers will gladly assist you in creating a tailored solution with customized parameters to fit your specific filtration needs

The chart below is in millimeters

Tool Code LWD (mm) SWD Min (mm) SWD Max (mm) Hole Size Min (mm) Hole Size Max (mm) Opening SQCM Min Opening SQCM Max Open Area Min Open Area Max Width (mm) Raw Thickness Min (mm) Raw Thickness Max (mm)
Tool Code LWD
(mm)
SWD
(mm)
Hole Size (mm) Opening/
SQCM
Open Area Width
(mm)
Raw Thickness
(mm)
Min Max Min Max Min Max Min Max Min Max
020 0.508 0.279 0.330 0.025 0.178 1162.79 1395.35 32% 75% 203.2 0.025 0.051
025 0.635 0.318 0.391 0.030 0.203 806.20 992.25 32% 75% 203.2 0.025 0.076
031 0.787 0.457 0.610 0.038 0.254 410.85 550.39 32% 82% 304.8 0.025 0.127
040 1.016 0.559 0.813 0.051 0.432 271.32 348.84 24% 85% 304.8 0.038

0.152

050 1.270 0.610 0.914 0.076 0.559 173.64 254.26 21% 89% 609.6 0.038 0.203
060 1.524 0.762 1.092 0.076 0.686 120.93 178.29 20% 90% 609.6 0.038 0.229
075 1.905 0.762 0.940 0.084 0.762 111.63 136.43 15% 90% 965.2 0.038 0.229
077 1.956 0.838 1.422 0.102 0.838 73.64 120.16 15% 90% 914.4 0.051 0.305
080 2.032 0.940 1.702 0.178 1.016 58.14 104.65 16% 90% 1219.2 0.051 0.356
090 2.286 1.143 1.422 0.178 1.143 62.02 77.52 16% 90% 609.6 0.051 0.356
100 2.540 1.016 1.956 0.178 1.168 38.76 73.64 16% 90% 965.2 0.051 0.432
105 2.667 1.270 1.956 0.178 1.219 38.76 54.26 20% 90% 609.6 0.051 0.457
125 3.175 1.270 2.819 0.203 1.321 23.26 50.39 20% 90% 1219.2 0.051 0.635
140 3.556 1.499 3.175 0.254 1.651 17.05 38.76 30% 90% 609.6 0.076 0.762
158 4.001 1.956 3.175 0.279 1.905 15.50 27.91 30% 90% 685.8 0.076 0.762
180 4.572 1.803 2.819 0.279 2.032 15.50 23.26 32% 90% 609.6 0.102 0.762
190 4.826 1.702 2.540 0.508 2.235 12.40 20.16 35% 90% 609.6 0.127 0.762
215 5.461 2.108 3.632 0.508 2.413 10.08 17.05 35% 90% 609.6 0.127 0.762
236 5.994 2.311 3.632 0.635 2.540 9.30 13.95 35% 90% 609.6 0.127 0.762
250 6.350 2.540 4.424 0.686 2.794 7.75 12.40 35% 90% 609.6 0.127 0.762
284 7.214 2.311 3.632 0.762 3.302 6.98 12.40 35% 90% 609.6 0.127 0.762
400 10.160 3.175 8.458 0.889 4.572 2.33 6.20 35% 90% 609.6 0.127 0.762
500 12.700 2.311 3.632 0.762 3.302 6.98 12.40 35% 90% 609.6 0.127 0.762

The chart below is in inches

Tool Code LWD (in) SWD Min (in) SWD Max (in) Hole Size Min (in) Hole Size Max (in) Opening SQIN Min Opening SQIN Max Open Area Min Open Area Max Width (in) Raw Thickness Min (in) Raw Thickness Max (in)
Tool Code LWD
(in)
SWD
(in)
Hole Size (in) Opening/
SQIN
Open Area Width
(in)
Raw Thickness
(in)
Min Max Min Max Min Max Min Max Min Max
020 0.020 0.0111 0.0133 0.001 0.007 7500 9000 32% 75% 8 0.001 0.002
025 0.025 0.0125 0.0154 0.0012 0.008 5200 6400 32% 75% 8 0.001 0.003
031 0.031 0.0182 0.0244 0.0015 0.01 2650 3550 32% 82% 12 0.001 0.005
040 0.040 0.0222 0.0323 0.002 0.017 1750 2250 24% 85% 12 0.0015

0.06

050 0.050 0.0244 0.0357 0.003 0.022 1120 1640 21% 89% 24 0.0015 0.008
060 0.060 0.0303 0.0435 0.003 0.027 780 1150 20% 90% 24 0.0015 0.009
075 0.075 0.0303 0.0370 0.0033 0.03 720 880 15% 90% 38 0.0015 0.009
077 0.077 0.0333 0.0556 0.004 0.033 475 775 15% 90% 36 0.002 0.012
080 0.080 0.0370 0.0667 0.007 0.04 375 675 16% 90% 48 0.002 0.014
090 0.090 0.0455 0.0556 0.007 0.045 400 500 16% 90% 24 0.002 0.014
100 0.100 0.0400 0.0769 0.007 0.046 250 475 16% 90% 38 0.002 0.017
105 0.105 0.0500 0.0769 0.007 0.048 250 350 20% 90% 24 0.002 0.018
125 0.125 0.0500 0.1111 0.008 0.052 150 325 20% 90% 48 0.002 0.025
140 0.140 0.0588 0.1250 0.01 0.065 110 250 30% 90% 24 0.003 0.03
158 0.158 0.0769 0.1250 0.011 0.075 100 180 30% 90% 27 0.003 0.03
180 0.180 0.0714 0.1111 0.011 0.08 100 150 32% 90% 24 0.004 0.03
190 0.190 0.0667 0.1000 0.02 0.088 80 130 35% 90% 24 0.005 0.03
215 0.215 0.0833 0.1429 0.02 0.095 65 110 35% 90% 24 0.005 0.03
236 0.236 0.0909 0.1429 0.025 0.1 60 90 35% 90% 24 0.005 0.03
250 0.250 0.1000 0.1667 0.027 0.11 50 80 35% 90% 24 0.005 0.03
284 0.284 0.0909 0.1429 0.03 0.13 45 80 35% 90% 24 0.005 0.03
400 0.400 0.1250 0.3333 0.035 0.18 15 40 35% 90% 24 0.005 0.03
500 0.500 0.2000 0.400 0.05 0.225 10 20 35% 90% 36 0.005 0.03

Contact Us

Phone: (800) 714-8736
Fax: (203) 294-7899

sales@dexmet.com

22 Barnes Industrial Rd. So.
Wallingford, CT 06492
United States of America

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