WO2001087456A2 - Method of attaching an end cap to porous filter media, and filter element which is a product thereof - Google Patents

Method of attaching an end cap to porous filter media, and filter element which is a product thereof Download PDF

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Publication number
WO2001087456A2
WO2001087456A2 PCT/US2001/015360 US0115360W WO0187456A2 WO 2001087456 A2 WO2001087456 A2 WO 2001087456A2 US 0115360 W US0115360 W US 0115360W WO 0187456 A2 WO0187456 A2 WO 0187456A2
Authority
WO
WIPO (PCT)
Prior art keywords
end cap
filter
filter member
filter medium
heating
Prior art date
Application number
PCT/US2001/015360
Other languages
French (fr)
Other versions
WO2001087456A3 (en
Inventor
Timothy L. Memmer
Original Assignee
Honeywell International Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Honeywell International Inc. filed Critical Honeywell International Inc.
Publication of WO2001087456A2 publication Critical patent/WO2001087456A2/en
Publication of WO2001087456A3 publication Critical patent/WO2001087456A3/en

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Classifications

    • 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
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2411—Filter cartridges
    • B01D46/2414—End caps including additional functions or special forms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
    • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
    • B01D29/111—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
    • B01D46/0001—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
    • B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
    • B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/1403—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the type of electromagnetic or particle radiation
    • B29C65/1412—Infrared [IR] radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/1429—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface
    • B29C65/1432—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation characterised by the way of heating the interface direct heating of the surfaces to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/114—Single butt joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1244—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue
    • B29C66/12441—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue being a single wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/53—Joining single elements to tubular articles, hollow articles or bars
    • B29C66/534—Joining single elements to open ends of tubular or hollow articles or to the ends of bars
    • B29C66/5344—Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially annular, i.e. of finite length, e.g. joining flanges to tube ends
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B29C66/543—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles joining more than two hollow-preforms to form said hollow articles
    • B29C66/5432—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles joining more than two hollow-preforms to form said hollow articles joining hollow covers and hollow bottoms to open ends of container bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832—Reciprocating joining or pressing tools
    • B29C66/8322—Joining or pressing tools reciprocating along one axis
    • B29C66/83221—Joining or pressing tools reciprocating along one axis cooperating reciprocating tools, each tool reciprocating along one axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2201/00—Details relating to filtering apparatus
    • B01D2201/29—Filter cartridge constructions
    • B01D2201/291—End caps
    • B01D2201/293—Making of end caps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2201/00—Details relating to filtering apparatus
    • B01D2201/29—Filter cartridge constructions
    • B01D2201/291—End caps
    • B01D2201/295—End caps with projections extending in a radial outward direction, e.g. for use as a guide, spacing means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2711/00—Use of natural products or their composites, not provided for in groups B29K2601/00 - B29K2709/00, for preformed parts, e.g. for inserts
    • B29K2711/12—Paper, e.g. cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/14—Filters

Definitions

  • the present invention relates to a method of joining one or more end caps to porous filter media, and to a filter element which is a product of the described process. More particularly, the present invention relates to a method of joining one or more end caps to porous filter media, without requiring extraneous adhesives, and in which part of the filter medium becomes at least partially embedded in the material of the end cap.
  • Adhesive use also involves the requirements of obtaining, storing, transporting and applying a suitable adhesive, and gluing the end caps to the filter tube in a separate operation from the attachment of the end caps to the filter medium.
  • the present invention provides a method of attaching an end cap to a filter member.
  • the method according to the invention begins with a step of providing a first plastic end cap configured to fit on an end of a filter member.
  • the end cap is preferably formed of a thermoplastic, which may be any thermoplastic, so long as it is compatible with the material being filtered.
  • Thermoplastics which may be used in connection with the present invention may be one or more materials selected from the group consisting of polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof.
  • One suitable thermoplastic material which may be used for fuel filter applications is an acetal resin.
  • the next step in the method is heating the end cap to soften an inner surface thereof.
  • the preferred method of heating the end cap involves applying infrared heat to the cap without contacting it.
  • the end cap is heated to a temperature above the melting point of the material thereof, to partially melt and soften the inner surface thereof.
  • the next step in the method according to the invention is contacting the filter member with the heated surface of the end cap.
  • the end cap is pressed into place against the filter member, using an appropriate machine, and enough force is applied thereto to partially embed the end of the filter member into the molten plastic.
  • the next step in the method involves holding the end cap in place against the filter medium until the end cap cools sufficiently for the material thereof to set, causing the filter member to adhere thereto.
  • Figure 1 is a side plan view of an infrared heating element disposed between a pair of end caps for a fuel filter element in accordance with the present invention.
  • Figure 2 is a side plan view of the end caps of Figure 1, disposed on opposite sides of a filter member.
  • Figure 3 is a side plan view of an assembled filter element according to the invention.
  • Figure 4 is an end plan view of the filter element of Figure 3, showing the structure of the filter member in phantom; and
  • Figure 5 is a cross-sectional detail view, partially broken away, taken along the line 5-5 in Figure 4.
  • FIG. 30 an illustrative example of a filter element, according to the invention, is shown generally at 30.
  • the filter element 30 is appropriate for use as a fuel filter in the illustrated embodiment.
  • the filter element includes a central filter member 20 having first and second end caps 10, 12 affixed to respective opposite ends thereof. ' As seen in phantom in Figure 2, each of the respective end caps 10, 12 are provided with inner surfaces 11, 13, respectively. Each of these inner surfaces 11, 13 contacts an end of the filter medium in the finished filter element.
  • a preferred material for the end caps 10, 12 is a thermoplastic resin material, which may be any thermoplastic, so long as it is compatible with the material being filtered.
  • Thermoplastic materials usable in the practice of the present invention include polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof.
  • One suitable thermoplastic material which may be used for fuel filter applications is an acetal resin polymer, which is a product of the polymerization of a composition which contains formaldehyde.
  • acetal resin polymer which may be used in the practice of the present invention, is that sold commercially by DuPont under the trademark "DELRIN" .
  • the filter member 20 is formed from an accordion-folded pleated sheet of porous filter material.
  • the filter member 20 is preferably formed from a fibrous paper material.
  • the filter member 20 is a generally tubular member, in which the pleated sheet of filter material is wrapped around and fastened back on itself, to form a modified cylindrical shape.
  • the filter element 30 is substantially D-shaped or kidney shaped, as seen from an end view thereof, and as illustrated by Figure 4. Other shapes could be used, depending on the specific filter application.
  • a fuel filter is shown for purposes of illustration, other types of filters such as, e.g., oil filters, could be made in a similar fashion to that described herein in connection with the fuel filter element 30, with the method modified as appropriate.
  • the method according to the invention begins with a step of providing a first plastic end cap 10 configured to fit on an end of a filter member 20.
  • a single end cap will suffice, but in most contemplated applications, both first and second end caps 10, 12 are provided for placement on opposite ends 22, 24 of the filter member 20.
  • the next step in the method is heating the end cap 10 or caps 10, 12 to soften an inner surface 11, 13 thereof.
  • the preferred method of heating the end cap 10 involves applying infrared heat to the cap without contacting it.
  • the infrared heat may be applied using a heating element 14 on an electric heater apparatus 16, as shown.
  • both end caps 12, 14 are heated simultaneously.
  • the next step in the method according to the invention is contacting the filter member 20 with the heated inner surface 11, 13 of the respective end cap 10, 12.
  • the first end cap 10 is pressed into place against the first end 22 of the filter member 20, using an appropriate machine, and the second end cap 12 is pressed into place against the second end 24 of the filter member, applying enough force to partially embed the outermost portions of ends 22, 24 of the filter member into the molten plastic of the respective end cap inner surface 11, 13.
  • the molten plastic of the end cap 10, 12 serves as the adhesive to bond the end cap 10, 12 in place on the filter member 20.
  • the elimination of the need for a supplemental adhesive provides a cost savings, as compared with the prior art, and also simplifies the manufacturing method by eliminating the application of adhesive.
  • attaching end caps to filter media following the method of the invention eliminates the necessity of obtaining, storing, transporting and applying an extraneous adhesive, and of applying glue to the end caps in a separate operation from the attachment of the end caps to the filter medium.
  • the next step in the method which will usually be the final step, involves holding the end cap 10 in place against the filter member 20 until the end cap cools sufficiently for the material thereof to stiffen, causing the filter member to adhere thereto, and forming a finished filter element 30.
  • the assembly process necessary at the filter element manufacturing facility is made simpler than it would be where end caps were cast in place around the ends of filter media.
  • specialized molds required for each filter end cap application configuration may be located at a different site than the filter manufacturing facility.
  • a specialty molding plant can make the end caps 10, 12 in a first location, and the end caps can subsequently be attached to the filter member 20 in a second location, where filter element assembly is the entire focus. This provides a more streamlined process at the second location than would otherwise be the case if the end caps were cast in place around the ends of the filter member.
  • the filter element 30 may then placed inside of a housing (not shown), in known fashion, to form a final filter product, or may be installed in a re-sealable housing which uses replaceable filter elements.

Abstract

A method of attaching an end cap to a filter member begins with a step of providing a first plastic end cap configured to fit on an end of a filter member. The next step in the method is heating the end cap to soften an inner surface thereof. The preferred method of heating the end cap involves applying infrared heat to the cap without contacting it. The next step in the method according to the invention is contacting the filter member with the heated surface of the end cap. Preferably the end cap is pressed into place against the filter member, using an appropriate machine, and applying enough force to partially embed the end of the filter member into the molten plastic. The next step in the method involves holding the end cap in place against the filter medium until the end cap cools sufficiently for the material thereof to stiffen, causing the filter member to adhere thereto.

Description

METHOD OF ATTACHING AN END CAP TO POROUS FILTER MEDIA, AND FILTER ELEMENT WHICH IS A PRODUCT THEREOF
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a method of joining one or more end caps to porous filter media, and to a filter element which is a product of the described process. More particularly, the present invention relates to a method of joining one or more end caps to porous filter media, without requiring extraneous adhesives, and in which part of the filter medium becomes at least partially embedded in the material of the end cap.
2. Description of the Background Art
Several different types of fluid filter assemblies are commonly used for many applications, and in particular, vehicles and internal combustion engines of many different types use fuel filters, air filters, and oil filters, each of which includes a filter element made of a porous material. Many of these types of filters use a filter element including a cylindrical or modified cylindrical tube of filter paper, or other fibrous material, as a filter medium, and this filter element also commonly includes a pair of opposed end caps at opposite ends of the tube for restricting or directing flow into the tube ends. Previously, the predominant practice has been to use an adhesive material on the inner facing surfaces of these end caps to fasten them to the filter tube, to form a filter element. Unfortunately, the use of adhesives involves several complicating factors. Some engineering theremoplastics are difficult to get adhesives to bond to, and further, adhesives may be applied inconsistently if the application tooling is imperfect. Adhesive use also involves the requirements of obtaining, storing, transporting and applying a suitable adhesive, and gluing the end caps to the filter tube in a separate operation from the attachment of the end caps to the filter medium.
Some designs have been proposed for molding such end caps sealingly around the tube of filter medium, such as that described in U.S. Patent number 5,891,337. Air filter elements, in particular, are commercially available in which a silicone elastomer material is cast in place surrounding the ends of a short cylindrical tube of pleated filter sheet material, and this silicone elastomer is suited for forming seals against an air filter housing when placed therein. Other related filter designs are suggested by U.S. patent numbers 4,374,026 and 5,252,204. This approach has a drawback of necessarily requiring a specialized mold for each filter application. Another approach suggested by U.S. patent number 4,882,055 is to cast both the filter media and the end caps simultaneously in a single molding operation. However, this method requires that each and every hole through the filter media be defined in the mold, and has a tendency to limit the filtration performance of the resultant product. A need still exists in the art for a method of assembling a filter element which does not require a specialized mold for each application, yet which may be performed without requiring a specialized adhesive in addition to the filter member and end caps.
SUMMARY OF THE INVENTION The present invention provides a method of attaching an end cap to a filter member. The method according to the invention begins with a step of providing a first plastic end cap configured to fit on an end of a filter member. The end cap is preferably formed of a thermoplastic, which may be any thermoplastic, so long as it is compatible with the material being filtered. Thermoplastics which may be used in connection with the present invention may be one or more materials selected from the group consisting of polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof. One suitable thermoplastic material which may be used for fuel filter applications is an acetal resin.
The next step in the method is heating the end cap to soften an inner surface thereof. The preferred method of heating the end cap involves applying infrared heat to the cap without contacting it. The end cap is heated to a temperature above the melting point of the material thereof, to partially melt and soften the inner surface thereof.
The next step in the method according to the invention is contacting the filter member with the heated surface of the end cap. Preferably the end cap is pressed into place against the filter member, using an appropriate machine, and enough force is applied thereto to partially embed the end of the filter member into the molten plastic.
The next step in the method involves holding the end cap in place against the filter medium until the end cap cools sufficiently for the material thereof to set, causing the filter member to adhere thereto.
Accordingly, it is an object of the present invention to provide a method of attaching one or more plastic end caps to a fluid filter element, which does not require an adhesive other than the material of the end cap.
It is a further object of the present invention to provide a filter element which is a product of the described method.
It is an advantage of the present invention that it eliminates a previously required expense associated with providing a supplemental adhesive.
For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side plan view of an infrared heating element disposed between a pair of end caps for a fuel filter element in accordance with the present invention. Figure 2 is a side plan view of the end caps of Figure 1, disposed on opposite sides of a filter member.
Figure 3 is a side plan view of an assembled filter element according to the invention. Figure 4 is an end plan view of the filter element of Figure 3, showing the structure of the filter member in phantom; and Figure 5 is a cross-sectional detail view, partially broken away, taken along the line 5-5 in Figure 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figures 2-3 of the drawings, an illustrative example of a filter element, according to the invention, is shown generally at 30. The filter element 30 is appropriate for use as a fuel filter in the illustrated embodiment. The filter element includes a central filter member 20 having first and second end caps 10, 12 affixed to respective opposite ends thereof. ' As seen in phantom in Figure 2, each of the respective end caps 10, 12 are provided with inner surfaces 11, 13, respectively. Each of these inner surfaces 11, 13 contacts an end of the filter medium in the finished filter element.
A preferred material for the end caps 10, 12 is a thermoplastic resin material, which may be any thermoplastic, so long as it is compatible with the material being filtered. Thermoplastic materials usable in the practice of the present invention include polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof. One suitable thermoplastic material which may be used for fuel filter applications is an acetal resin polymer, which is a product of the polymerization of a composition which contains formaldehyde. One suitable type of acetal resin polymer, which may be used in the practice of the present invention, is that sold commercially by DuPont under the trademark "DELRIN" .
The filter member 20 is formed from an accordion-folded pleated sheet of porous filter material. The filter member 20 is preferably formed from a fibrous paper material.
As seen best in the phantom view thereof in Figure 4, the filter member 20 is a generally tubular member, in which the pleated sheet of filter material is wrapped around and fastened back on itself, to form a modified cylindrical shape. In the depicted embodiment, which is provided for illustrative purposes, the filter element 30 is substantially D-shaped or kidney shaped, as seen from an end view thereof, and as illustrated by Figure 4. Other shapes could be used, depending on the specific filter application. Further, while a fuel filter is shown for purposes of illustration, other types of filters such as, e.g., oil filters, could be made in a similar fashion to that described herein in connection with the fuel filter element 30, with the method modified as appropriate.
Referring now to Figure 1, the method according to the invention begins with a step of providing a first plastic end cap 10 configured to fit on an end of a filter member 20. In some applications, a single end cap will suffice, but in most contemplated applications, both first and second end caps 10, 12 are provided for placement on opposite ends 22, 24 of the filter member 20. The next step in the method is heating the end cap 10 or caps 10, 12 to soften an inner surface 11, 13 thereof. The preferred method of heating the end cap 10 involves applying infrared heat to the cap without contacting it. The infrared heat may be applied using a heating element 14 on an electric heater apparatus 16, as shown. Preferably, both end caps 12, 14 are heated simultaneously. The next step in the method according to the invention is contacting the filter member 20 with the heated inner surface 11, 13 of the respective end cap 10, 12. Preferably the first end cap 10 is pressed into place against the first end 22 of the filter member 20, using an appropriate machine, and the second end cap 12 is pressed into place against the second end 24 of the filter member, applying enough force to partially embed the outermost portions of ends 22, 24 of the filter member into the molten plastic of the respective end cap inner surface 11, 13.
Referring now to Figure 5, it may be seen that the end 24 of the filter member 20 is partially embedded in the material of the inner surface 13 of the end cap 12.
In practicing the method according to the present invention, the molten plastic of the end cap 10, 12 serves as the adhesive to bond the end cap 10, 12 in place on the filter member 20. This eliminates the need for any other supplemental adhesive, as is used in present assembly processes. The elimination of the need for a supplemental adhesive provides a cost savings, as compared with the prior art, and also simplifies the manufacturing method by eliminating the application of adhesive. Furthermore, attaching end caps to filter media following the method of the invention eliminates the necessity of obtaining, storing, transporting and applying an extraneous adhesive, and of applying glue to the end caps in a separate operation from the attachment of the end caps to the filter medium.
The next step in the method, which will usually be the final step, involves holding the end cap 10 in place against the filter member 20 until the end cap cools sufficiently for the material thereof to stiffen, causing the filter member to adhere thereto, and forming a finished filter element 30.
By using the method according to the present invention as outlined herein, the assembly process necessary at the filter element manufacturing facility is made simpler than it would be where end caps were cast in place around the ends of filter media. Where the method of the invention is used, specialized molds required for each filter end cap application configuration may be located at a different site than the filter manufacturing facility. A specialty molding plant can make the end caps 10, 12 in a first location, and the end caps can subsequently be attached to the filter member 20 in a second location, where filter element assembly is the entire focus. This provides a more streamlined process at the second location than would otherwise be the case if the end caps were cast in place around the ends of the filter member.
The filter element 30 may then placed inside of a housing (not shown), in known fashion, to form a final filter product, or may be installed in a re-sealable housing which uses replaceable filter elements.
Although the present invention has been described herein with respect to a preferred embodiment thereof, the foregoing description is intended to be illustrative, and not restrictive. Those skilled in the art will realize that many modifications of the preferred embodiment could be made which would be operable. All such modifications which are within the scope of the claims are intended to be within the scope and spirit of the present invention.

Claims

What is claimed is:
1. A method of attaching an end cap to a filter member, comprising the steps of: providing a first plastic end cap configured to fit on an end of a filter member formed of a porous filter medium; heating the end cap to soften an inner surface thereof; contacting a first end of the filter medium with the inner surface of the first end cap; and holding the first end cap in place against the filter medium until it adheres thereto.
2. The method of claim 1, wherein pressure is applied to the end cap during the holding step.
3. The method of claim 1, wherein the first end cap is formed of a thermoplastic material selected from the group consisting of polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof.
4. The method of claim 1, wherein the first end cap is formed of an acetal resin material.
5. The method of claim 1, wherein a portion of the filter member becomes at least partially embedded in the inner surface of the first end cap.
6. The method of claim 1 , wherein the filter material comprises paper.
7. The method of claim 1, wherein the heating is accomplished by bringing the end cap into proximity with a heating element without touching the end cap therewith.
8. The method of claim 1, further comprising the steps of: providing a second plastic end cap configured to fit on a second end of the filter member; heating the second end cap to soften an inner surface thereof; contacting a second end of the filter medium with the inner surface of the second end cap; and holding the second end cap in place against the filter medium until it adheres thereto.
9. The method of claim 8, wherein the first and second end caps are formed of a thermoplastic material selected from the group consisting of polyamides, polyimides, polyesters, polyolefins, polysulfones, fluoropolymers, and mixtures thereof.
10. The method of claim 9, wherein the first and second end caps are formed of an acetal resin material.
11. The method of claim 1, wherein said heating step is accomplished by placing the end cap proximate an infrared heat source.
12. A method of assembling a filter element, comprising the steps of: providing first and second plastic end caps configured to fit on opposite ends of a filter member formed of a porous filter medium; heating the first and second end caps to soften inner surfaces thereof; contacting a first end of the filter medium with an inner surface of the first end cap, and contacting a second end of the filter medium with an inner surface of the second end cap; and holding the first and second end caps in place against the filter medium until they adhere thereto.
13. A fluid filter element which is a product of the method of claim 1.
14. A fluid filter element which is aproduct of the method of claim 2.
15. A fluid filter element which is a product of the method of claim 12.
16. A fuel filter element which is a product of the method of claim 9.
PCT/US2001/015360 2000-05-15 2001-05-14 Method of attaching an end cap to porous filter media, and filter element which is a product thereof WO2001087456A2 (en)

Applications Claiming Priority (2)

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US70596000A 2000-05-15 2000-05-15
US09/705,960 2000-05-15

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1700684A1 (en) * 2005-03-11 2006-09-13 MANN+HUMMEL GmbH Process for producing a tight connection between a multilayer plastic material and a filter medium
DE102005040417A1 (en) * 2005-08-25 2007-03-01 Mann + Hummel Gmbh end disk
WO2008142428A3 (en) * 2007-05-23 2009-03-12 Walker Filtration Ltd Filter unit
WO2013017383A1 (en) * 2011-08-03 2013-02-07 Gebr. Becker Gmbh Air filter attachment for side channel compressor
US11020689B2 (en) 2012-04-27 2021-06-01 Sartorius Stedim Biotech Gmbh Filter element with improved testability after dry steaming

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US3457339A (en) * 1965-12-08 1969-07-22 Pall Corp Process for making end capped filter elements
US4795524A (en) * 1986-02-07 1989-01-03 Nippondenso Co., Ltd. Apparatus for fixing cap on end of filter element
US5225077A (en) * 1989-04-03 1993-07-06 Pall Corporation Filter cartridge with end densification ring
US5891337A (en) * 1994-11-30 1999-04-06 Air-Maze Corporation Filter with molded end cap and media spacer

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US3457339A (en) * 1965-12-08 1969-07-22 Pall Corp Process for making end capped filter elements
US4795524A (en) * 1986-02-07 1989-01-03 Nippondenso Co., Ltd. Apparatus for fixing cap on end of filter element
US5225077A (en) * 1989-04-03 1993-07-06 Pall Corporation Filter cartridge with end densification ring
US5891337A (en) * 1994-11-30 1999-04-06 Air-Maze Corporation Filter with molded end cap and media spacer

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1700684A1 (en) * 2005-03-11 2006-09-13 MANN+HUMMEL GmbH Process for producing a tight connection between a multilayer plastic material and a filter medium
DE102005040417A1 (en) * 2005-08-25 2007-03-01 Mann + Hummel Gmbh end disk
WO2008142428A3 (en) * 2007-05-23 2009-03-12 Walker Filtration Ltd Filter unit
GB2462396A (en) * 2007-05-23 2010-02-10 Walker Filtration Ltd Filter unit
US20100205798A1 (en) * 2007-05-23 2010-08-19 Brian Walker Filter unit
GB2462396B (en) * 2007-05-23 2012-06-20 Walker Filtration Ltd Filter unit
US9009975B2 (en) 2007-05-23 2015-04-21 Walker Filtration Limited Filter unit
WO2013017383A1 (en) * 2011-08-03 2013-02-07 Gebr. Becker Gmbh Air filter attachment for side channel compressor
CN103874859A (en) * 2011-08-03 2014-06-18 格布尔.贝克尔有限责任公司 Air filter attachment for side channel compressor
JP2014524533A (en) * 2011-08-03 2014-09-22 ゲーエーベーエル．ベッケル・ゲーエムベーハー Air filter attachment for side channel compressor
US9675921B2 (en) 2011-08-03 2017-06-13 Gebr. Becker Gmbh Air filter attachment for side channel compressor
US11020689B2 (en) 2012-04-27 2021-06-01 Sartorius Stedim Biotech Gmbh Filter element with improved testability after dry steaming

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