Filter media comprising a pre-filter layer

Patent metadata

Field	Value
Publication number	US-2016175752-A1
Application number	US-201414577247-A
Country	US
Kind code	A1
Filing date	Dec 19, 2014
Priority date	Dec 19, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

Filter media comprising a pre-filter layer and related components, systems, and methods associated therewith are provided. In some embodiments, the pre-filter layer may be designed to impart desirable properties to the filter media, such as a high gamma and/or long service life, while having relatively minimal or no adverse effects on another property of the filter media that is important for a given application. For instance, a pre-filter layer may be used to improve the upstream removal of fine particulate matter, which may clog a downstream efficiency layer comprising submicron fibers and reduce filtration performance. The pre-filter layer may be configured to increase service life and/or increase the gamma of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

First claim

What is claimed is:

1 . A filter media, comprising:
a pre-filter layer comprising first fibers having a median diameter of less than or equal to about 2 microns, the pre-filter layer having a thickness greater than or equal to about 20 microns, wherein the pre-filter layer has a basis weight of less than about 30 g/m 2 and an initial DOP efficiency of less than or equal to about 90%; and a second layer comprising second fibers having a median diameter of less than or equal to about 1 micron, wherein the second layer has an initial DOP efficiency of greater than or equal to about 60% and wherein the initial DOP efficiency of the second layer is greater than the pre-filter layer.

2 . A filter media, comprising:
a pre-filter layer comprising first fibers having a median diameter of less than or equal to about 2 microns, the pre-filter layer having a thickness greater than or equal to about 20 microns, wherein the pre-filter layer has a basis weight of less than about 30 g/m 2 and an initial DOP efficiency of less than or equal to about 90%; and a polymeric membrane having an initial DOP efficiency of greater than or equal to about 60% and wherein the initial DOP efficiency of the polymeric membrane is greater than the pre-filter layer.

3 . A filter media as in claim 1 , wherein the surface area of the pre-filter layer is greater than or equal to about 1.75 m 2 /g and less than or equal to about 45 M 2 /g.

4 . A filter media as in claim 1 , wherein the thickness of the pre-filter layer is less than or equal to about 1 mm.

5 . A filter media as in claim 1 , wherein the pre-filter layer has an initial DOP efficiency of greater than or equal to about 10%.

6 . A filter media as in claim 1 , wherein the pre-filter layer has a solidity of less than or equal to about 25%,

7 . A filter media as in claim 1 , wherein the pre-filter layer has a pressure drop of less than 35 mm H 2 O.

8 . A filter media as in claim 1 , wherein the first fibers have a median diameter less than or equal to about 1 micron.

9 . A filter media as in claim 1 , wherein the first fibers are continuous fibers.

10 . A filter media as in claim 1 , wherein the first fibers are synthetic fibers.

11 . A filter media as in claim 1 , wherein the second fibers have a median fiber diameter of less than or equal to about 0.5 microns.

12 . A filter media as in claim 1 , wherein the median diameter of the first fibers is greater than the median diameter of the second fibers.

13 . A filter media as in claim 2 , wherein the polymeric membrane comprises a fluorinated polymer.

14 . A filter media as in claim 1 , wherein the pre-filter has a gamma of greater than or equal to about 7.

15 . A filter element comprising the filter media of claim 1 .

16 . A filter element as in claim 15 , wherein the filter element is a HEPA filter, ULPA filter, HVAC filter, or a face mask.

17 . A filter media as in claim 1 , wherein the pre-filter layer comprises continuous fibers and the second layer comprises synthetic fibers.

18 . A filter media as in claim 1 , wherein the pre-filter layer and the second layer comprise synthetic fibers.

19 . A filter media as in claim 1 , wherein the pre-filter layer comprises synthetic fibers and the second layer comprises continuous fibers.

20 . A filter media as in claim 1 , wherein the pre-filter layer and/or the second layer comprise electrospun fibers.

21 . A filter media as in claim 1 , wherein the pre-filter layer and/or the second layer comprise meltblown fibers.

22 . A method comprising:
filtering a fluid using the filter media or filter element of claim 1 .

Assignees

• Hollingsworth & Vose Co

Inventors

• Jaganathan Sudhakar
• Anantharamaiah Nagendra
• Silin Maxim

Classifications

• B01D39/1623

  of synthetic origin · CPC title

• B01D2239/0631

  Electro-spun · CPC title

• B01D39/1692

  Other shaped material, e.g. perforated or porous sheets · CPC title

• B01D2239/065

  More than one layer present in the filtering material · CPC title

• A62B23/025

  the filter having substantially the shape of a mask (surgical face masks A41D13/11) · CPC title