Surface vs Depth Filtration Brochure


Catalog excerpts

Surface vs Depth Filtration Brochure - 1

SURFACE FILTRATION versus DEPTH FILTRATION WHAT IS TETRATEX®? Tetratex filter media can enhance the performance of your fabric filter by utilising surface filtration technology as opposed to traditional depth filtration methods. Tetratex is a proprietary expanded microporous PTFE (Polytetrafluoroethylene) membrane, manufactured solely by Donaldson Membranes. It is laminated to a variety of base substrates to provide a complete range of media including woven and felted textile media for conversion into all types of filter bag as well as pleatable media for cartridges style elements. DEPTH vs SURFACE For collection to be effective, any individual particle in the gas stream must be slowed, intercepted and collected on or within the filter media. In the case of conventional filter fabrics, the interstices between the fibres within the structure of the media are often considerably larger than the particles to be collected. The dust particles penetrate the surface of the media to ‘close off’ the open pores, forming a filter cake on the surface of the media. This is termed ‘depth filtration’. Without a filter cake on their surface, conventional filter media are rarely able to collect fine particulate efficiently; media blinding and atmospheric emissions occur over time as individual dust particles penetrate into and beyond the filter media. Tetratex filter media utilises true ‘surface filtration’ technology. A microporous ePTFE membrane, it is laminated to the surface of a supporting substrate and it is this membrane which acts as the filter media. The construction of the membrane, with millions of pores per cm2, is such that submicron particles are captured on its surface. The backing substrate is merely a support and plays no part in the filtration process. All particulate is collected on the surface of the membrane. No reliance on a filter cake. No penetration of dust into or beyond the media. Depth Filtration Particles penetrate the structure of the media and form a filter cake on the surface Surface Filtration Particles are collected on the surface of th

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Surface vs Depth Filtration Brochure - 2

Tetratex ePTFE membrane filter media can bring about a wide range of benefits for your fabric filter baghouse; the unique structure of the membrane prevents the penetration of fine dusts into the supporting substrate and facilitates excellent cleanability due to its non-stick characteristics. DECREASE Particulate emissions Baghouse pressure drop Cleaning regime Maintenance costs Element changes Airflow Filter bag life Product collection Ability to handle sticky/moist dust By employing Tetratex ePTFE membrane filter media, increased system airflow can be achieved through reduced filter...

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Surface vs Depth Filtration Brochure - 3

In cases where end-users are seeking to reduce their energy consumption, Tetratex ePTFE membrane filter media is a proven technology. By considering standard fan laws governing air movement systems (eg. backward inclined fansets), we can calculate the potential cash savings by operating a typical system at a reduced filter pressure drop. Q = (V x AP) / Eff. By maintaining required airflow at a reduced filter DP at a lower fan speed, energy absorbed by the fan is reduced and significant savings in power consumption can be achieved. The following example is based on a system with an estimated...

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Surface vs Depth Filtration Brochure - 4

Donaldson Membranes is committed to working closely with partners to provide comprehensive technical and sales support. Our experience in innovative design, manufacturing, filtration knowledge and technical support will help you and your organisation to succeed. Having an enviable resource of more than thirty years of dry filtration experience, Donaldson Membranes is able to provide a thorough and educated evaluation of your system process to best determine the most suitable Tetratex filter media solution. The Donaldson Membranes technical team can provide assistance with manufacturing...

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