Filter structure with two or more layers of fine fiber having extended useful service life
First Claim
1. A fine fiber filter media comprising a single layer of filter substrate, the substrate having a first surface and a second surface, the substrate having a permeability of about 0.03 to 15 m-sec−
- 1 and an efficiency greater than 10%, the first surface and the second surface each comprising a layer of fine fiber having a diameter of about 0.001 to 0.5 microns, the layer of fine fiber having a thickness of less than 5 microns, the layer of fine fiber formed in an amount effective to obtain a pore size of about 0.0001 to 5 microns, an overall efficiency under ASTM-1215-89 with monodisperse 0.78 micron polystyrene latex particles at 20 ft/min velocity of about 50% to 90% in any one layer and to obtain an efficiency of greater than 90% in the layers combined.
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Accused Products
Abstract
The use of fine fiber or fiber having a fiber diameter of about 0.0001 to 0.5 microns has become an important design tool for filter media. Common filter media have been prepared with a layer of fine fiber on typically formed the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency but a substantial improvement in lifetime.
241 Citations
41 Claims
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1. A fine fiber filter media comprising a single layer of filter substrate, the substrate having a first surface and a second surface, the substrate having a permeability of about 0.03 to 15 m-sec−
- 1 and an efficiency greater than 10%, the first surface and the second surface each comprising a layer of fine fiber having a diameter of about 0.001 to 0.5 microns, the layer of fine fiber having a thickness of less than 5 microns, the layer of fine fiber formed in an amount effective to obtain a pore size of about 0.0001 to 5 microns, an overall efficiency under ASTM-1215-89 with monodisperse 0.78 micron polystyrene latex particles at 20 ft/min velocity of about 50% to 90% in any one layer and to obtain an efficiency of greater than 90% in the layers combined.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of removing a particulate from an air borne stream, the particulate comprising a liquid particulate, a solid particulate or mixtures thereof, the method comprises:
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(a) placing a filter structure in an air stream having a particulate; and
(b) directing the air stream through the filter structure while monitoring the useful life of the filter structure;
said filter structure comprising a fine fiber filter media and single layer of a filter substrate the substrate having a permeability of about 0.03 to 15 m-sec−
1 and an efficiency of greater than 10%, the substrate having a first surface and a second surface, the first surface and the second surface each comprising a layer of fine fiber having a diameter of about 0.001 to 0.5 microns, the layer of fine fiber having a thickness of less than 5 micron, the fine fiber layer formed in an amount affective to obtain a pore size of about 0.001 to 5 microns, an efficiency under ASTM-1215-89 with monodisperse 0.78 micron polystyrene latex particles at 20 ft/min velocity of about 50% to 90% in any one layer and to obtain an efficiency of greater than 90% in the layers combined.- View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A filter structure consisting essentially of one layer of filter substrate and three or more layers of fine fiber, the substrate layer having a first surface and a second surface, the substrate having a permeability of about 0.03 to 15 m-sec−
- 1 and an efficiency of greater than 5%, the surfaces comprising three or more layers of the fine fiber on the substrate, each fine fiber layer comprising fine fiber having a diameter of about 0.01 to 0.5 micron, each fine fiber layer having a thickness of less than 5 microns, the fine fiber layer formed in the amount effective to obtain a pore size of about 0.0001 to 5 microns, an efficiency under ASTM 1215-89 with monodisperse 0.78 micron polystyrene latex particles at 20 ft/min velocity of about 50% to 90% in any one layer and to obtain an overall efficiency of greater than 90% in the layers combined.
- View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A fine fiber filter media consisting essentially of a single layer of filter substrate, the substrate having a first surface and a second surface, the substrate having a permeability of about 0.03 to 15 m-sec−
- 1 and an efficiency greater than 20%, the first surface and the second surface each comprising a layer of fine fiber having a diameter of about 0.001 to 0.5 microns, the layer of fine fiber having a thickness of less than 5 microns, the layer of fine fiber formed in an amount effective to obtain a pore size of about 0.0001 to 5 microns, an overall efficiency under ASTM-1215-89 with monodisperse 0.78 micron polystyrene latex particles at 20 ft/min velocity of about 50% to 90% in any one layer and to obtain an efficiency of greater than 90% in the layers combined.
- View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41)
Specification