Filter element with regenerable bulk material filling and method for making same

Claim 1

A filter element for filtering a fluid medium, said element having an inner space comprising a tubular chamber (17) with an inner peripheral wall and an outer peripheral wall through which walls the medium to be filtered can pass, said chamber having sealing closure elements (14, 15) at its ends and said filter element having an annular filter member (21) through which said fluid medium can flow in an essentially radial manner, said filter member (21) comprising a bulk-material filling of regenerable, filtration-active substances in the form of a particulate and/or fibrous structure, said peripheral walls having a degree of porosity which enables the said fluid medium to pass through them and with a predetermined direction of flow, said peripheral walls holding captive the said bulk material filling, at least one of said peripheral walls being constituted as a wet-resistant support layer for said filter member, and said bulk material filling consisting of auxiliary filter agents capable of being carried to and deposited at said one peripheral wall by said fluid medium, said deposited auxiliary filter agents forming on said one wall, as the medium is being filtered, a deep bed filter (21) characterized by decreasing porosity in said predetermined direction of flow.

Claim 14

The method of making a filter element for filtering a fluid medium, said element having an inner space comprising a tubular chamber (17) with an inner peripheral wall and an outer peripheral wall through which walls the medium to be filtered can pass, said chamber having sealing closure elements (14, 15) at its ends, comprising the steps of: a) filling the said chamber (17) with a loose, low-density bulk-material filling mixture of regenerable, filtration-active substances in the form of particles and/or fibres having differing thicknesses and/or fiber lengths and or particle sizes and/or particle geometries and in an essentially random pattern distribution, b) establishing a flow of said fluid medium through the said chamber by introducing said fluid medium into said chamber through one of said peripheral walls, and into contact with said filtration-active substances, and channelling it out through the other of said peripheral walls, and c) simultaneously with the step of introducing the fluid medium and channelling it, the step of re-arranging said filtration-active substances from said heterogeneous pattern, as a consequence of said fluid flow, so that there is formed on the other of said peripheral walls, a filter cake characterized by a decreasing porosity in the direction of flow, said decreasing porosity being formed by the thinner and/or shorter and/or smaller particles being carried relatively far in the direction of flow by said fluid, and the thicker and/or longer and/or larger particles being carried relatively shorter distances along the direction of flow by said fluid, to the end that the filter cake is constituted as a deep bed filter characterized by a decreasing porosity in the direction of flow of said fluid.

Claim 15

The method of making a filter element for filtering a fluid medium, said element having an inner space comprising a tubular chamber (17) with an inner peripheral wall and an outer peripheral wall through which walls the medium to be filtered can pass, said chamber having sealing closure elements (14, 15) at its ends, comprising the steps of: a) filling the said chamber (17) with a loose, low-density bulk-material filling mixture of regenerable, filtration-active substances in the form of particles and/or fibres having differing thicknesses and/or fiber lengths and or particle sizes and/or particle geometries and in an essentially random pattern distribution, b) establishing a flow of said fluid medium through the said chamber by introducing said fluid medium into said chamber through one of said peripheral walls, and into contact with said filtration-active substances, and channelling it out through the other of said peripheral walls, and c) simultaneously with the step of introducing the fluid medium and channelling it, the step of re-arranging said filtration-active substances from said heterogeneous pattern, as a consequence of said fluid flow, so that there is formed on the other of said peripheral walls, a filter cake characterized by a decreasing porosity in the direction of flow, said decreasing porosity being formed by the thinner and/or shorter and/or smaller particles being carried relatively far in the direction of flow by said fluid, and the thicker and/or longer and/or larger particles being carried relatively shorter distances along the direction of flow by said fluid, to the end that the filter cake is constituted as a deep bed filter characterized by a decreasing porosity in the direction of flow of said fluid.