Coalescing filter media

• US 10,625,196 B2
• Filed: 05/31/2016
• Issued: 04/21/2020
• Est. Priority Date: 05/31/2016
• Status: Expired due to Fees

• Current Assignee: Hollingsworth & Vose Company
• Original Assignee: Hollingsworth & Vose Company
• Inventors: Boesner, Jens-Peter
• Primary Examiner(s): Holecek, Cabrena
• Application Number:
  US15/168,709
• Publication Number:
  US 20170341006A1
• Time in Patent Office: 1,421 Days
• CPC Class Codes: B01D 2239/0421 Rendering the filter material hydrophilic
• CPC Class Codes: B01D 2239/0478 on a layer of the filter
• CPC Class Codes: B01D 2239/0654 Support layers
• CPC Class Codes: B01D 2239/0695 Wound layers
• CPC Class Codes: B01D 2239/08 Special characteristics of binders
• CPC Class Codes: B01D 2239/1233 Fibre diameter
• CPC Class Codes: B01D 2239/1258 Permeability
• CPC Class Codes: B01D 2239/1291 Other parameters
• CPC Class Codes: B01D 2275/105 Wound layers
• CPC Class Codes: B01D 2279/30 for treatment of exhaust gases from IC Engines
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: B01D 39/2017 the material being filamentary or fibrous
• CPC Class Codes: B01D 46/0001 Making filtering elements
• CPC Class Codes: B01D 46/003 including coalescing means for the separation of liquid
• CPC Class Codes: B01D 46/521 using folded, pleated material
• CPC Class Codes: B01D 46/528 using wound sheets B01D46/527 takes precedence

Abstract

Filter media, filter elements, and methods for filtering an gas stream are described herein. In some embodiments, the filter media may comprise a fiber web comprising a plurality of fibers and having a particular oil repellency level. For instance, in certain embodiments, the surface chemistry of the fiber web may be tailored to impart a particular surface energy density that matches the surface energy density of the fluid (e.g., an oil, a lubricant, and/or a cooling agent) being removed from the gas stream. In some embodiments, the fiber web may be wrapped around a core. For example, the fiber web may be wrapped around the core such that it forms two or more layers around the core. In some cases, the fiber web may be perforated. In certain embodiments, an gas stream comprising a fluid (e.g., an oil, a lubricant, and/or a cooling agent) may be passed through the fiber web, filter media, and/or filter element such that at least a portion of the fluid coalesces on the fiber web. Fiber webs, filter media, and/or filter elements as described herein may be particularly well-suited for applications that involve filtering gas streams containing oil, lubricants, and/or cooling agents (e.g., gas streams generated by a compressor) though the media may also be used in other applications. Advantageously, the fiber webs, filter media, and/or filter elements described herein may significantly reduce or prevent fouling of the filter caused by oil or other liquids.

Claims

1. A method for filtering an oil, lubricant, and/or cooling agent from a gas stream, the method comprising:

passing the gas stream including the oil, lubricant, and/or cooling agent through a filter element, wherein the filter element comprises a fiber web wrapped around a core such that at least two layers of the fiber web are formed, the fiber web comprising;

a plurality of fibers having an average fiber diameter of at least 0.01 microns and less than or equal to 50 microns;

a basis weight of at least 1 g/m² and less than or equal to 270 g/m²; and

a thickness of at least 0.01 mm and less than or equal to 5.0 mm,

wherein the fiber web has an oil repellency level of between 4 and 6;

wherein the fiber web has an oil carry over of less than 20%, and

wherein the oil, lubricant, and/or cooling agent has a surface tension of between 22 mN/m and 33 mN/m measured at 23°

C. and 50% RH.

2. The method of claim 1, wherein the gas stream is generated by a compressor, natural gas production equipment, a distillation column, an evaporator, a thermal oil ventilator, a crankcase ventilator, a combustion engine, and/or an exhaust conduit.

3. The method of claim 1, wherein the fiber web comprises binder fibers, wherein a weight percentage of binder fibers present in the fiber web is at least about 0 wt % and less than or equal to about 10 wt %.

4. The method of claim 1, wherein the fiber web comprises glass fibers, wherein the weight percentage of glass fibers present in the fiber web is greater than or equal to about 0% and less than or equal to about 99% by weight of the total fibers in the fiber web.

5. The method of claim 1, wherein the fiber web comprises synthetic fibers, wherein the weight percentage of synthetic fibers present in the fiber web is greater than or equal to about 1% and less than or equal to about 100% by weight of the total fibers in the fiber web.

6. The method of claim 1, wherein the fiber web comprises cellulose fibers, wherein the weight percentage of cellulose fibers present in the fiber web is greater than or equal to about 1% and less than or equal to about 100% by weight of the total fibers in the fiber web.

7. The method of claim 1, wherein the fiber web has at least one modified surface.

8. The method of claim 1, wherein the fiber web has an initial efficiency of greater than or equal to about 1% and less than or equal to about 99.99%.

9. The method of claim 1, wherein at least one surface of the fiber web is coated with a coating.

10. The method of claim 9, wherein the coating comprises a fluorinated polymer.