Filter
AssigneeLydall, Inc.
InventorStephen A. Wald
Life of this patent
Estimating the term…
Abstract
There is provided a filter wherein the filtering means has a non-woven needled textile filter fabric with an overall bulk density of at least 6 pounds per cubic foot and bulk density gradient such that the bulk density at the face surface of the fabric is greater than the bulk density at the back surface of the fabric. In conjunction with that bulk density gradient is a filtering gradient such that the fineness of filtration at the back face surface is greater than the fineness of filtration at the surface. The filter may be in any convenient form, such as the bag of an air conveyor filter or a vacuum cleaner filter.
Claims27
A filter for separating suspended solid particulate matter comprising an intake means, a filter means and a discharge means, for passing the suspended solid particulate matter to the filter means and collecting the solid particulate matter on the filter means, said filter means comprising a non-woven needled textile filter fabric having at least 5,000 needle punches per square inch and constructed from a batt of staple textile fibers and said fabric having on an all-fiber basis:
- (a) a face surface associated with the discharge means and a back surface associated with the intake means;
- (b) an overall bulk density of at least 6 pounds per cubic foot;
- (c) a bulk density gradient such that the bulk density at the face surface is at least 50% greater than the bulk density at the back surface;
- (d) a filtering gradient such that the fineness of filtration at the face surface is greater than the fineness of filtration at the back surface;
- (e) a gas permeability of at least 3 CFM per square foot at a pressure drop of 0.5 inch of water;
- and
- (f) a fineness of filtration such that the dynamic leakage is 7.0% or less.
Dependencies are inferred from the claim text.