Frequently Asked Questions about Preveil

Here is a list of frequently asked questions related to Preveil ePTFE membrane filter bags, and answers on when you should consider switching filter bag types.

Features & Benefits

Why do Preveil membrane filter bags operate at a lower pressure drop?

At what emission requirement should I consider upgrading from my standard filter to the surface filtration provided by a bag laminated with Preveil membrane?

Will filter bag life be increased by using Preveil membrane filter bags?

Under what conditions should I consider switching from a polyester filter bag to a filter bag constructed from acrylic? (The same question applies to both ePTFE membrane as well as conventional polyester and acrylic filter bags.)

Application

Q. Why do Preveil* membrane filter bags operate at a lower pressure drop?
A. The pressure drop across a filter bag almost always increases due to one of two reasons: 1. Surface blinding caused by agglomeration of moist or sticky dust on the bag surface. 2. Depth penetration of fine particulate into the fabric, which cannot be removed during cleaning. Preveil membranes nearly eliminate these two causes of high-pressure drop because of its microporous structure, ultra-high efficiency, and dust-releasing properties.
Q. At what emission requirement should I consider upgrading from my standard filter to the surface filtration provided by a bag laminated with Preveil membrane?
A. This is a tricky question since all emission levels are conditional upon inlet grain loading, filtration velocities, particle size and distribution, and collector style. Generally emission requirements of less than 0.009 grains per cubic foot or below 20 mg. per cubic meter may require a filter bag constructed with ePTFE membrane (Preveil membrane) to achieve these levels on an ongoing basis. Dust populations with a significant percentage of particulate below 10 microns are especially difficult to maintain low outlet emission levels.
Specifications

Q. Is filter bag life increased by using Preveil membrane filter bags?
A. Preveil membrane filter bags rarely require replacement due to high pressure drop or low airflow. On the rare occasion of failure, filters require replacement due to loss of strength of base fabric. Preveil has been documented to increase bag life by up to five times in some installations.
Q. When should I consider switching from a polyester filter bag to an acrylic filter bag?
A. Polyester can lose strength due to hydrolysis where moisture and heat are present; temperatures averaging above 230° F are especially vulnerable. Please contact us for assistance.

GE Energy

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Frequently Asked Questions about Preveil

Features & Benefits

Frequently Asked Questions about Preveil

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