Fibrous media

• US 10,316,468 B2
• Filed: 02/01/2018
• Issued: 06/11/2019
• Est. Priority Date: 01/28/2009
• Status: Active Grant

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Gupta, Hemant
• Primary Examiner(s): Fitzsimmons, Allison G
• Application Number:
  US15/886,594
• Publication Number:
  US 20180223478A1
• Time in Patent Office: 495 Days
• Field of Search: None
• CPC Class Codes: D04H 1/42 characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
• CPC Class Codes: D04H 1/4218 Glass fibres
• CPC Class Codes: D04H 1/435 Polyesters
• CPC Class Codes: D04H 1/43828 sheath-core
• CPC Class Codes: D04H 1/43832 side-by-side
• CPC Class Codes: D04H 1/43835 Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• CPC Class Codes: D04H 1/43838 Ultrafine fibres, e.g. microfibres
• CPC Class Codes: D21F 11/04 paper or board consisting on two or more layers
• CPC Class Codes: D21F 11/14 Making cellulose wadding, filter or blotting paper
• CPC Class Codes: D21F 9/006 paper or board consisting of two or more layers
• CPC Class Codes: D21H 13/24 Polyesters
• CPC Class Codes: D21H 13/40 vitreous, e.g. mineral wool, glass fibres
• CPC Class Codes: D21H 27/08 Filter paper self-supporting filtering material B01D39/14; making on paper-making machines D21F11/14

Abstract

A multi-faceted family of non-woven webs that can take the form of a filter media, an adaptable forming process and a machine capable of making the range of media are disclosed. The filter medium can have a first surface and a second surface defining a thickness. The medium can comprise a region having a gradient. Such a gradient is formed by having a medium wherein the concentration of a fiber, a property or other component varies from one surface to the next surface. The gradient region of the media can comprise the entire thickness of the medium or can comprise a region that comprises a portion of the media thickness. The media are characterized by the presence of a continuous change of the fiber concentration or property within the region.

Claims

1. A nonwoven filter medium comprising a wet-laid nonwoven layer having a thickness, the thickness comprising a gradient of a first cellulose fiber and a second cellulose fiber, wherein the first and second fibers differ in terms of fiber length, fiber diameter, fiber morphology, or a combination thereof;

wherein the gradient is a continuous change in a concentration of the first cellulose fiber and a continuous change in a concentration of the second cellulose fiber, characterized by the absence of an interface.

2. The nonwoven filter medium of claim 1 wherein the gradient is a linear gradient.

3. The nonwoven filter medium of claim 1 wherein the medium further comprises one or more fibers selected from the group comprising polyester fiber, bicomponent fiber, and glass fiber.

4. The nonwoven filter medium of claim 1 further comprising bonded fiber.

5. The nonwoven filter medium of claim 4 wherein the bonded fiber comprises a bicomponent fiber, a resinous binder, or a crosslinking reagent.

6. The nonwoven filter medium of claim 1 wherein the medium further comprises a non-gradient region.

7. A composite filter unit comprising the nonwoven filter medium of claim 1 and a base layer comprising a conventional medium, membrane, cellulosic medium, synthetic medium, glass medium scrim, or expanded metal support.