US20060230727A1 - Filtration element having a variable density sidewall - Google Patents
Filtration element having a variable density sidewall Download PDFInfo
- Publication number
- US20060230727A1 US20060230727A1 US11/255,585 US25558505A US2006230727A1 US 20060230727 A1 US20060230727 A1 US 20060230727A1 US 25558505 A US25558505 A US 25558505A US 2006230727 A1 US2006230727 A1 US 2006230727A1
- Authority
- US
- United States
- Prior art keywords
- strands
- thickness
- sidewall part
- filtration element
- bag
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
- B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
- B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0001—Making filtering elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/02—Particle separators, e.g. dust precipitators, having hollow filters made of flexible material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/18—Filters characterised by the openings or pores
- B01D2201/188—Multiple filtering elements having filtering areas of different size
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2275/00—Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2275/10—Multiple layers
- B01D2275/105—Wound layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2275/00—Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2275/30—Porosity of filtering material
- B01D2275/305—Porosity decreasing in flow direction
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Materials (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
- Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
Abstract
A filtration element formed of overlapping fibrous strands or components. Those fibrous strands at the side of the filtration element which first receives the gas flow being of one thickness and those fibrous strands at the side of the filtration element where the gas flow exits being of a thickness substantially less than the one thickness of the strands at the opposite sidewall of the element.
Description
- This is a continuation-in-part of and claims the benefit of provisional application Ser. No. 60/672,894, filed Apr. 19, 2005.
- This invention relates to a filtration element for gases and will have application to bag type filters.
- In this invention, the filtration element was formed of overlapping fibrous strands or components with the strands varying in diameter or thickness, the largest of which is at the side of the filter which first receives the gas flow for filtration and the smallest of which is at the opposite side of the filter where the gas exists after passing through the filtration element. Further, the side of the filter which first receives the gas flow will generally be more rigid than the opposite side of the filter so as to provide a substantially incompressible surface.
- Accordingly, it is an object of this invention to provide a filtration element which is of economical construction and which is of efficient operation.
- Still another object of this invention is to provide a filtration element which is for gases and which provides for more even distribution of filtered particulate matter throughout the thickness of the element.
- Other objects of the invention become apparent upon the reading of the following description.
-
FIG. 1 is a fragmentary perspective view showing an example of the apparatus which can be used to make the filtration element of this invention. -
FIG. 2 is a side view of a filter element in the form of a bag having a portion of the bag sidewall broken away to illustrate in cross-section the filtration strands forming the sidewall of the filter bag. -
FIG. 3 is a side view of the filter bag showing in illustrative form the varying thicknesses of the filtration strands. - The preferred embodiment herein described is not intended to be exhaustive or to limit the invention to precise form disclosed. It is chosen and described to explain the principles of the invention and its application and practical use to enable others skilled in the art to best utilize the invention.
- This invention may be best understood by the following descriptions and the workings of the equipment which is used to produce the filter element, seen in the drawing as a
filter bag 10. As illustrated inFIG. 1 , a quantity of material, preferably polypropylene or other thermoplastic materials capable of producing filaments when molten and air dried, is introduced into anextruder 12 athopper 14 and is fed through anozzle 16. A plurality of ring heaters 18circumscribe nozzle 16 and serve to produce heat sufficient to liquefy the thermoplastic material as it flows through the nozzle.Nozzle 16 terminates in a plurality of laterally spaceddischarge outlets 22 through which the thermoplastic material in its molten state is propelled in melted andfibrous strands 20 by heated air frommanifolds 23 toward amandrel 28.Mandrel 28 may be formed from metal, wood or similar material and resembles in its outer configuration the intended shape of thefilter bag 10 to be produced. Mandrel 28 is rotated about anaxis 35 within the flow path of thefibrous strands 20 fromnozzle discharge outlets 22. Normally, Mandrel 28 is placed between 1 to 3 feet fromoutlets 22 and rotated at a constant speed such as between 30 to 80 rpm. The fibrous material orstrands 20 are sufficiently cooled as they reach themandrel 28 so as to be formed about the mandrel in layers. - In this invention, the diameters of the
strands 20 are varied as the thickness of the sidewall 32 ofbag 10 increases. This is best illustrated in viewingFIGS. 2 and 3 where a section of the sidewall of the filter bag has been broken away for illustrative purposes. InFIG. 2 thestrands 20 are shown in cross-section, the largest diameter strands being at the inside of the bag and the smallest diameter of the strands being at the outside of the bag with the gas flow through the bag being from the inside towards the outside of the bag. InFIG. 3 , there is shown in illustrative form the varying thickness of thestrands 20 with the strands becoming progressively thinner from the inside to the outside of the bag in the direction of gas flow through the bag. In this manner, the outer margin of the sidewall of the bag will have its strands more compactly layered so as to increase the degree of filtration as the outer edges of the bag are reached. Thus, the larger particulate matter being filtered from the gas will first become entrained within the filter bag closer to the inside of the bag with the smaller particulate matter becoming entrained closer to the outside of the bag. This will produce more even distribution of the filtered particulate matter throughout the bag. - The thickness of the
strands 20 ofbag 10 may range from 50 to 200 microns towards the inside of the bag and progressively become smaller in transverse dimension to 0.5 microns at the outside surface of the bag with the bag being approximately ¾ to 1 inch thick. The precise thickness or transverse dimension of the strands of the fibrous material and thickness of the bag can vary depending upon the type of material intended to be filtered and the size of the filter bag. - In producing
filter bag 10, the thicker strands are first wound upon the mandrel and then as the bag's thickness progressively increases, the temperature produced by heaters 18 can be increased so as to make the thermoplastic material more molten with the air pressure produced atmanifolds 23 increased, thus increasing the length of the strands and reducing their transverse dimension. In this manner, by selectively increasing the temperature of the molten thermoplastic material and/or increasing the air pressure by which the molten thermoplastic material is driven through and propelled from the nozzles, the thickness of the strands can be selectively varied as they are wound upon the mandrel to produce the sidewall of the filter bag or cartridge depending upon the type of filtration element being produced. - Also, in addition to varying the thickness of the strands, by varying the temperature of the molten thermoplastic material and/or varying the volume of air by which the material is driven through and propelled from the nozzles, the stiffness of the strands can be increased so that the
inner wall section 20 a of the filter bag becomes stiff or rigid. Bag side walls may substantially collapse during use due to the gas pressure within the bag. This reduces the bag's permeability and filtering capacity. By rigidifying a wall section of the bag at the side where the gas first contacts, the bag strands remain open to provide intervals or voids between the strands to catch or entrain filtered particles. The depth ofwall section 20 a can vary, even extending the entire thickness of the filter bag, depending upon the filtration characteristics desired. - The invention is not to be limited to the details above given but may be modified within the scope of the appended claims.
Claims (7)
1. A filtration element comprising a sidewall part, said sidewall part having a first side which the gas flow through the element first contacts and a second side from which said gas flow exits said element, said sidewall part including overlapping fibrous strands, those said strands at said sidewall part first side being of one thickness and those said strands at said sidewall part second side being of a thickness substantially less than the thickness of said sidewall part first side.
2. The filtration element of claim 1 wherein said strands vary progressively in transverse dimension from said sidewall part first side to said sidewall part second side.
3. The filtration element of claim 1 or 2 wherein said strands vary regressively in rigidity from said sidewall part first side toward said sidewall part second side to form a substantially rigid sidewall part at said first side.
4. A method of forming a filtration element comprising the steps of:
a. expelling thermoplastic material through a nozzle by gas pressure to form strands of fibrous material,
b. heating said material prior to its expulsion from said nozzle,
c. forming said strands of fibrous material into a sidewall of said filtration element, and
d. varying the thickness of said strands with the thicker of the strands being at the side of the filtration element where the gas flow through the element first flows.
5. The method of claim 4 wherein step a includes varying the gas pressure through said nozzle to vary the thickness of said strands.
6. The method of claim 4 wherein step b includes varying the temperature of said material prior to its expulsion from said nozzle to vary the thickness of said strands.
7. The method of claim 4 wherein step d includes varying the stiffness of the strands at the side of the filtration element where the gas flow through the element first flows.
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/255,585 US20060230727A1 (en) | 2005-04-19 | 2005-10-21 | Filtration element having a variable density sidewall |
EP06007668A EP1728543A3 (en) | 2005-04-19 | 2006-04-12 | Filtration element having a variable density sidewall |
JP2006115750A JP2006297389A (en) | 2005-04-19 | 2006-04-19 | Filter element having variable-density side wall |
BRPI0601299-0A BRPI0601299A (en) | 2005-04-19 | 2006-04-19 | filtration element having a variable density sidewall |
KR1020060035270A KR20060110230A (en) | 2005-04-19 | 2006-04-19 | Filtration element having a variable density sidewall and method for manufacturing thereof |
CA2544065A CA2544065C (en) | 2005-04-19 | 2006-04-19 | Filtration element having a variable density sidewall |
CNA2006100748361A CN1864803A (en) | 2005-04-19 | 2006-04-19 | Filtration element having a variable density sidewall |
US11/735,852 US20070227968A1 (en) | 2005-04-19 | 2007-04-16 | Filtration element having a variable density sidewall |
US12/759,461 US7955407B2 (en) | 2005-04-19 | 2010-04-13 | Filtration element having a variable density sidewall |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US67289405P | 2005-04-19 | 2005-04-19 | |
US11/255,585 US20060230727A1 (en) | 2005-04-19 | 2005-10-21 | Filtration element having a variable density sidewall |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US67289405P Continuation | 2005-04-19 | 2005-04-19 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/735,852 Continuation-In-Part US20070227968A1 (en) | 2005-04-19 | 2007-04-16 | Filtration element having a variable density sidewall |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060230727A1 true US20060230727A1 (en) | 2006-10-19 |
Family
ID=37114214
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/255,585 Abandoned US20060230727A1 (en) | 2005-04-19 | 2005-10-21 | Filtration element having a variable density sidewall |
US12/759,461 Active US7955407B2 (en) | 2005-04-19 | 2010-04-13 | Filtration element having a variable density sidewall |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/759,461 Active US7955407B2 (en) | 2005-04-19 | 2010-04-13 | Filtration element having a variable density sidewall |
Country Status (6)
Country | Link |
---|---|
US (2) | US20060230727A1 (en) |
EP (1) | EP1728543A3 (en) |
JP (1) | JP2006297389A (en) |
CN (1) | CN1864803A (en) |
BR (1) | BRPI0601299A (en) |
CA (1) | CA2544065C (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106693554A (en) * | 2017-01-23 | 2017-05-24 | 王宇轩 | Air purifier based on silk thread filtration |
Citations (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4116738A (en) * | 1976-01-14 | 1978-09-26 | Pall Corporation | Continuous production of tubular modular filter elements using nonwoven webs from thermoplastic fibers and products |
US5352517A (en) * | 1986-03-24 | 1994-10-04 | Ensci, Inc. | Iron oxide coated substrates |
US5665479A (en) * | 1995-12-12 | 1997-09-09 | N.V. Bekaert S.A. | Sintered multilayer metal fiber web |
US5725750A (en) * | 1996-04-19 | 1998-03-10 | Sumitomo Electric Industries, Ltd. | Process for producing porous iron metal body |
US6010604A (en) * | 1998-02-04 | 2000-01-04 | Stauffer; John E. | Neural network packing |
US6165244A (en) * | 1999-03-13 | 2000-12-26 | Aaf International, Inc. | Filter media with fluid stream positioned fibers |
US6171684B1 (en) * | 1995-11-17 | 2001-01-09 | Donaldson Company, Inc. | Filter material construction and method |
US6231646B1 (en) * | 1999-03-11 | 2001-05-15 | Chemco Manufacturing Company, Inc. | Paint overspray exhaust air filter |
US6387141B1 (en) * | 1998-09-21 | 2002-05-14 | Firma Carl Freudenberg | Depth air filter having fibers intertwined by liquid-jetting |
US6409785B1 (en) * | 2000-08-07 | 2002-06-25 | Bha Technologies, Inc. | Cleanable HEPA filter media |
US6485811B1 (en) * | 1994-09-28 | 2002-11-26 | Toray Industries, Inc. | Nonwoven fabric for pleated filters, and a production process therefor |
US20030084788A1 (en) * | 2001-06-22 | 2003-05-08 | Fraser Ladson L | Foam coated air filtration media |
US6585794B2 (en) * | 2000-11-07 | 2003-07-01 | Sumitomo Electric Industries, Ltd. | Nonwoven metal fabric and method of making same |
US20040211160A1 (en) * | 2002-05-16 | 2004-10-28 | Branofilter Gmbh | Multi-layer filter structure and use of a multi-layer filter structure |
US6926828B2 (en) * | 2002-01-25 | 2005-08-09 | Inoac Corporation | Fluid filter |
US20050235619A1 (en) * | 2002-05-28 | 2005-10-27 | Beate Heinz | Filter medium |
US20050279062A1 (en) * | 2004-05-11 | 2005-12-22 | Bernd Reinsch | Device for cleaning gas mixtures and method for its manufacture |
Family Cites Families (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4594202A (en) * | 1984-01-06 | 1986-06-10 | Pall Corporation | Method of making cylindrical fibrous filter structures |
US4726901A (en) | 1984-01-06 | 1988-02-23 | Pall Corporation | Cylindrical fibrous structures with graded pore size |
US4536439A (en) * | 1985-01-07 | 1985-08-20 | E. I. Du Pont De Nemours And Company | Light weight filter felt |
US4661132A (en) * | 1985-08-15 | 1987-04-28 | Allied Corporation | Themally formed gradient density filter |
US4612237A (en) * | 1985-12-13 | 1986-09-16 | E. I. Du Pont De Nemours And Company | Hydraulically entangled PTFE/glass filter felt |
JPH0791754B2 (en) * | 1988-06-21 | 1995-10-04 | ユニ・チャーム株式会社 | Composite non-woven |
JPH0798131B2 (en) * | 1991-03-15 | 1995-10-25 | チッソ株式会社 | Cylindrical filter and manufacturing method thereof |
US5290628A (en) * | 1992-11-10 | 1994-03-01 | E. I. Du Pont De Nemours And Company | Hydroentangled flash spun webs having controllable bulk and permeability |
US6146436A (en) * | 1994-08-05 | 2000-11-14 | Firma Carl Freudenberg | Cartridge filter |
JPH08309124A (en) * | 1995-05-12 | 1996-11-26 | Toyobo Co Ltd | Cylindrical filter medium and manufacture thereof |
US6657229B1 (en) * | 1996-05-28 | 2003-12-02 | United Microelectronics Corporation | Semiconductor device having multiple transistors sharing a common gate |
JP3686918B2 (en) * | 1996-10-16 | 2005-08-24 | 森村興産株式会社 | Filtration device for solid-liquid separation of sewage, wastewater, etc. |
JPH1136169A (en) * | 1997-07-15 | 1999-02-09 | Tounen Tapirusu Kk | Production of melt-blown nonwoven fabric and cylindrical filter comprising melt-blown nonwoven fabric |
JPH11156125A (en) * | 1997-12-01 | 1999-06-15 | Roki Techno Co Ltd | Depth type filter |
BR9916370B1 (en) | 1998-12-19 | 2010-01-26 | non-braided laminate. | |
US6936554B1 (en) * | 2000-11-28 | 2005-08-30 | Kimberly-Clark Worldwide, Inc. | Nonwoven fabric laminate with meltblown web having a gradient fiber size structure |
US6736914B2 (en) * | 2001-12-20 | 2004-05-18 | Aaf-Mcquay, Inc. | Series arrangement for forming layered fibrous mat of differing fibers and controlled surfaces |
JP3802839B2 (en) * | 2002-05-24 | 2006-07-26 | 呉羽テック株式会社 | Nonwoven fabric for filters and filters for engines |
-
2005
- 2005-10-21 US US11/255,585 patent/US20060230727A1/en not_active Abandoned
-
2006
- 2006-04-12 EP EP06007668A patent/EP1728543A3/en not_active Withdrawn
- 2006-04-19 CN CNA2006100748361A patent/CN1864803A/en active Pending
- 2006-04-19 BR BRPI0601299-0A patent/BRPI0601299A/en not_active IP Right Cessation
- 2006-04-19 CA CA2544065A patent/CA2544065C/en active Active
- 2006-04-19 JP JP2006115750A patent/JP2006297389A/en active Pending
-
2010
- 2010-04-13 US US12/759,461 patent/US7955407B2/en active Active
Patent Citations (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4116738A (en) * | 1976-01-14 | 1978-09-26 | Pall Corporation | Continuous production of tubular modular filter elements using nonwoven webs from thermoplastic fibers and products |
US5352517A (en) * | 1986-03-24 | 1994-10-04 | Ensci, Inc. | Iron oxide coated substrates |
US6485811B1 (en) * | 1994-09-28 | 2002-11-26 | Toray Industries, Inc. | Nonwoven fabric for pleated filters, and a production process therefor |
US6171684B1 (en) * | 1995-11-17 | 2001-01-09 | Donaldson Company, Inc. | Filter material construction and method |
US5665479A (en) * | 1995-12-12 | 1997-09-09 | N.V. Bekaert S.A. | Sintered multilayer metal fiber web |
US5725750A (en) * | 1996-04-19 | 1998-03-10 | Sumitomo Electric Industries, Ltd. | Process for producing porous iron metal body |
US6010604A (en) * | 1998-02-04 | 2000-01-04 | Stauffer; John E. | Neural network packing |
US6387141B1 (en) * | 1998-09-21 | 2002-05-14 | Firma Carl Freudenberg | Depth air filter having fibers intertwined by liquid-jetting |
US6231646B1 (en) * | 1999-03-11 | 2001-05-15 | Chemco Manufacturing Company, Inc. | Paint overspray exhaust air filter |
US6165244A (en) * | 1999-03-13 | 2000-12-26 | Aaf International, Inc. | Filter media with fluid stream positioned fibers |
US6409785B1 (en) * | 2000-08-07 | 2002-06-25 | Bha Technologies, Inc. | Cleanable HEPA filter media |
US6585794B2 (en) * | 2000-11-07 | 2003-07-01 | Sumitomo Electric Industries, Ltd. | Nonwoven metal fabric and method of making same |
US20030084788A1 (en) * | 2001-06-22 | 2003-05-08 | Fraser Ladson L | Foam coated air filtration media |
US6926828B2 (en) * | 2002-01-25 | 2005-08-09 | Inoac Corporation | Fluid filter |
US20040211160A1 (en) * | 2002-05-16 | 2004-10-28 | Branofilter Gmbh | Multi-layer filter structure and use of a multi-layer filter structure |
US20050235619A1 (en) * | 2002-05-28 | 2005-10-27 | Beate Heinz | Filter medium |
US20050279062A1 (en) * | 2004-05-11 | 2005-12-22 | Bernd Reinsch | Device for cleaning gas mixtures and method for its manufacture |
Also Published As
Publication number | Publication date |
---|---|
EP1728543A3 (en) | 2007-10-10 |
CN1864803A (en) | 2006-11-22 |
CA2544065C (en) | 2013-05-21 |
US7955407B2 (en) | 2011-06-07 |
EP1728543A2 (en) | 2006-12-06 |
BRPI0601299A (en) | 2006-12-19 |
JP2006297389A (en) | 2006-11-02 |
US20100193427A1 (en) | 2010-08-05 |
CA2544065A1 (en) | 2006-10-19 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |