CA1078749A - Autogenously bonded filter assemblies and method of bonding same - Google Patents
Autogenously bonded filter assemblies and method of bonding sameInfo
- Publication number
- CA1078749A CA1078749A CA291,843A CA291843A CA1078749A CA 1078749 A CA1078749 A CA 1078749A CA 291843 A CA291843 A CA 291843A CA 1078749 A CA1078749 A CA 1078749A
- Authority
- CA
- Canada
- Prior art keywords
- filter
- metal
- filter media
- membrane
- housing
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims description 26
- 230000000712 assembly Effects 0.000 title description 6
- 238000000429 assembly Methods 0.000 title description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 90
- 239000002184 metal Substances 0.000 claims abstract description 90
- 239000012528 membrane Substances 0.000 claims abstract description 78
- 238000009792 diffusion process Methods 0.000 claims abstract description 22
- 238000005304 joining Methods 0.000 claims abstract description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 19
- 239000010935 stainless steel Substances 0.000 claims description 14
- 238000005245 sintering Methods 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910000601 superalloy Inorganic materials 0.000 claims description 3
- 229910000856 hastalloy Inorganic materials 0.000 claims description 2
- 229910001026 inconel Inorganic materials 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims 2
- 239000010941 cobalt Substances 0.000 claims 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims 2
- 210000004379 membrane Anatomy 0.000 description 62
- 238000005219 brazing Methods 0.000 description 8
- 238000003466 welding Methods 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 235000012771 pancakes Nutrition 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
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
- B01D46/52—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
- 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
- B01D29/01—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 flat filtering elements
- B01D29/012—Making filtering elements
-
- 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
- B01D29/01—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 flat filtering elements
- B01D29/05—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 flat filtering elements supported
- B01D29/07—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 flat filtering elements supported with corrugated, folded or wound filtering sheets
-
- 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
- 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
- B01D29/13—Supported filter elements
- B01D29/15—Supported filter elements arranged for inward flow filtration
- B01D29/21—Supported filter elements arranged for inward flow filtration with corrugated, folded or wound sheets
-
- 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
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2027—Metallic material
- B01D39/2041—Metallic material the material being filamentary or fibrous
- B01D39/2044—Metallic material the material being filamentary or fibrous sintered or bonded by inorganic agents
-
- 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
- B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2265/00—Casings, housings or mounting for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2265/04—Permanent measures for connecting different parts of the filter, e.g. welding, glueing or moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2271/00—Sealings for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2271/02—Gaskets, sealings
Abstract
ABSTRACT
An autogenous or sinter bond between metallic filter media and other metal components of a filter assembly is produced by joining the parts through a diffusion bonding membrane. The membrane comprises a web of small diameter metal fibrils which will sinter bond to both the filter media and the other filter parts to form a physically strong and leak-free seal.
An autogenous or sinter bond between metallic filter media and other metal components of a filter assembly is produced by joining the parts through a diffusion bonding membrane. The membrane comprises a web of small diameter metal fibrils which will sinter bond to both the filter media and the other filter parts to form a physically strong and leak-free seal.
Description
1¢787~9 BACKGROUND OF THE INVENTION
This invention relates to filters having a porous metallic filter media suitable for the mechanical filtering of both liquids and gases and to a method for their manufacture.
More particularly, this invention relates to the bonding of - other metal components to a metallic filter media to form a filter assembly.
Metallic filter media typically comprise very finely woven screen, usually utilized in a plurality of superposed layers, or a sintered web or mat of metal fibrils. Often a rather coarse metal screen is placed on either side of a metal fibril web to provide physical protection and to increase the strength of the web. Filters employing metallic media find extensive use in high temperature or corrosive environments.
Construction of filter assemblies containing metallic filter media presents difficult problems in bonding the porous ,~
'`,r medium to the connecting solid components. It is necessary to obtain a strong, leak-free joint between the parts in order to obtain a useful and reliable filter. The solid components of a filter assembly typically comprise end plates or caps in the case of a filter medium of cylindrical shape and a con-fining ring or housing in the case of a flat, or pack, filter.
A number of techniques have been proposed and are used to bond metallic filter media to connecting components -~ 25 of a filter assembly. Adhesives such as the epoxies have been used for this purpose, but the resulting filter assembly is limited to relatively low temperature applications.
For high temperature applications, bonding is usually accomplished by brazing, fusion welding or resistance welding. While brazing can produce strong, leak-free bonds, this technique is beset with problems. The metallic filter media, being porous, displays a strong capillary action toward -the molten brazing metal. Consequently, brazing metal migrates
This invention relates to filters having a porous metallic filter media suitable for the mechanical filtering of both liquids and gases and to a method for their manufacture.
More particularly, this invention relates to the bonding of - other metal components to a metallic filter media to form a filter assembly.
Metallic filter media typically comprise very finely woven screen, usually utilized in a plurality of superposed layers, or a sintered web or mat of metal fibrils. Often a rather coarse metal screen is placed on either side of a metal fibril web to provide physical protection and to increase the strength of the web. Filters employing metallic media find extensive use in high temperature or corrosive environments.
Construction of filter assemblies containing metallic filter media presents difficult problems in bonding the porous ,~
'`,r medium to the connecting solid components. It is necessary to obtain a strong, leak-free joint between the parts in order to obtain a useful and reliable filter. The solid components of a filter assembly typically comprise end plates or caps in the case of a filter medium of cylindrical shape and a con-fining ring or housing in the case of a flat, or pack, filter.
A number of techniques have been proposed and are used to bond metallic filter media to connecting components -~ 25 of a filter assembly. Adhesives such as the epoxies have been used for this purpose, but the resulting filter assembly is limited to relatively low temperature applications.
For high temperature applications, bonding is usually accomplished by brazing, fusion welding or resistance welding. While brazing can produce strong, leak-free bonds, this technique is beset with problems. The metallic filter media, being porous, displays a strong capillary action toward -the molten brazing metal. Consequently, brazing metal migrates
-2- ~
from the joint area into the filter media reducing the effective filter area and often preventing the formation of uniform fillets.
Additionally, the brazing metal is of different composition than that of the filter media and of the other metal components of the filter assembly. In some corrosive environments, this will cause localized electrolytic corrosion and early failure.
Brazing also requires a short time-temperature cycle which effectively rules out furnace brazing techniques. Brazing ; of stainless steel filter media requires temperatures in excess of the oxidation point thus necessitating use of either an inert atmosphere or a protective flux. If a protective flux is used, it must be subsequently removed and this is an operation which is both costly and unreliable.
Both resistance welding and fusion welding are compli-cated by the difference in effective thickness between the filtermedia and the relatively massive metal components to which it is joined. The excessive heat employed by use of these tech-niques tends to fuse a portion of the filter media, and so reduce its effective filtering area, or to distort the metal components of the filter assembly. Heat distortion is often so extensive as to require machining of the welded assembly to obtain the desired finished dimensions. In addition, the machining step may introduce undesirable metal particulates into the downstream portion of the filter assembly.
Lastly, it has been proposed to attach metal strips over the edges of the filter media by means of crimping or welding and thereafter fusion welding the metal strip to the filter end plates. This technique is disclosed in U.S. Patent No. 3,426,910. While this joining method produces a reliable seal between the media and the other metal components making up the filter assembly, it does result in the loss of effective filter area particularly in the case of relatively short, cylin-drical filters. Moreover, this joining technique is not 10~8749 adaptable for use with a flat, or pack filter.
SUMMARY OF THE INVENTION
Metallic filter media are joined to other metal components of a filter assembly by sinter bonding the media to the metal components through a diffusion bonding membrane.
The diffusion bonding membrane comprises a web of metal fibrils which is metallurgically compatible with both the filter media ; and the other metal components. In a preferred embodiment, the filter media, the diffusion bonding membrane and the other metal components of the filter assembly are of identical compo-sition.
The diffusion bonding membrane is placed between the filter media edges and the metal components. Thereafter, the assembly is sintered, preferably in a vacuum furnace, at a .,~.; , ( 15 temperature below the melting point of the metals for a time ;'~
i sufficient to develop a sinter bond between the filter media and the bonding membrane and between the bonding membrane and ~ the other metal components of the filter assembly.
:~ Hence, it is an object of this invention to provide aprocess for the joining of metallic filter media to other metal - components.
It is another object of this invention to provide filter assemblies in which the filter media is metallurgically bonded to other metal components making up the assembly.
Yet another object of this invention is to sinter weld metallic filter media to other metal components of a filter assembly.
A specific object of this invention is to sinter bond metallic filter media to other metal components through use of a metal fibril, diffusion bonding membrane.
DISCUSSION OF THE INVENTION
Metallic filter media, including very finely-woven metal screen and sintered, metal fibril webs, may be sinter bonded to more massive metal filter components by means of a diffusion bonding membrane. The diffusion bonding membrane comprises a thin web of metal fibrils which have the ability to readily sinter to an adjoining metal part at high temperature. Composition of the metal fibrils making up the bonding membrane must be metallurgi-cally compatible with both the filter media and the metal component parts making up the finished filter assembly. By metallurgical compatibility is meant the ability to form a strong sinter or autogenous bond at a temperature where at the shape and properties of the component parts of the filter assembly are unaffected.
Metallurgical comparability is most readily obtained by using the same metal or alloy for the filter media, the bonding membrane and the other metal component parts of the assembly.
Appropriate metals for use in the filter assemblies of this invention include the stainless steels, Inconel, Hastelloy, the nickel-base super alloys and various iron, nickel and cobalt-base alloys. Of these metals, the stainless steels find the most general application.
The diffusion bonding membranes of this invention may be fabricated from the same metal fibrils as are used to manufacture sintered metal fibril webs used as filter media. The fibrils themselves may have a diameter in the range of 2-40 microns and a length in the general range of 1/2 to 6 inches. In most instances the smaller fibrils, those having a diameter of about 4 to 16 microns and a length of 1/2 to 1 inches, are preferred. The fibrils may be produced, for example, by the process described in the Webber et al patent, U.S. 3,379,000. Metal fibrils produced by other known processes may be used as well.
t A~ k --5---` ~078749 Metal fibril compacts suitable for use as the diffu~
sion bonding membranes of this invention may be fabricated from the fibrils in the following manner. First, a loose mat of uniformly dispersed, randomly oriented intertwining metal fibrils is formed. This mat is then compressed to increase its density. The compressed mat is next annealed to relieve stresses and reduce its elasticity. Thereafter, the annealed web is rolled to obtain a bonding membrane of the desired thickness. The finished shee*s or membranes display a high degree of physical integrity but must be protected against dents and nicks which could prevent proper sintering of the seal during fabrication of the filter elements.
The loose, metal fibril mats used in making bonding membranes may be prepared by introducing separated fibrils into an upwardly moving stream of high velocity air by which they are transported into contact with a downwardly-facing reticulated web. Fibrils build up on the web and form a mat of interlaced, randomly dispersed fibrils. This mat has a low density, on the order of 1% of the density of an equivalent volume of solid metal, but has sufficient strength for subsequent handling. Procedures and apparatus for mat forming are disclosed in greater detail in U.S. Patent No. 3,505,038. Additionally, metal fibril mats of a variety of metal alloys are commercially available under the trade designation, "Brunsmet Web".
It is desirable that the diffusion bonding membranes be of low to intermediate density so that they can deform suffi-ciently to conform to any irregularities of the filter media edges. At the same time, it is necessary that the membranes be sufficiently dense to provide a strong, leak-free seal. A
density in the range of about 5% to 40%, based on the density of an equiva]ent volume of solid metal, is generally appropriate.
lt is preferred that the density be in the range of about 15~, to 25%.
The diffusion bonding membranes are desirably quite ! thin, generally in the range of about 0.005 to 0.05 inches in thickness. However, membrane thickness is not particularly critical as multiple membrane layers can be used. A membrane ~; 5 thickness of 0.02 to 0.03 inches is appropriate and works well for stainless steel filter assemblies.
Fabrication and bonding techniques, using the diffu-sion bonding membranes of this invention, are quite simple. In the case of a short, cylindrical or "pancake" type filter, the filter assembly typically consists of the filter media bonded between a pair of end plates. The filter media may comprise a plurality of superposed, finely-woven screens or a sintered, metal fibril compact either alone or with relatively coarse facing or backup screens on either side of the compact.
The filter medium is preferably folded into a pleated configur-ation, formed into a cylindrical shape and welded to form a closed loop.
The diffusion bonding membrane is cut to conform in size and shape with the end caps. Final assembly is accomplished by placing a bonding membrane inside one of the end caps and carefully locating the filter media on the membrane and centered within the end cap. Care must be taken to insure that the filter media edge is in complete contact with the bonding membrane.
Thereafter, the other end cap and bonding membrane is placed on the filter media again being sure of complete contact. The assembly is then compressed as in a punch press to densify the bonding membrane and force it into the filter media at all points of contact.
Diffusion bonding of the filter media to the end caps through the bonding membrane is accomplished by sintering the assembly at a temperature below the melting point of the metals ,~ '' , for a time sufficient to form an autogenous or sinter bond.
Sintering temperature is tai`lored to the metals used in the filter assembly. Appropriate sintering temperatures for stainless steels, for example, are about 2000F to 2200F
for a time of about 1 to 3 hours. It is preferred to carry out the sintering step in a vacuum. After sintering is com-plete, it is preferred to cool the filter assen~ly quickly by backfllling the vacuum furnace with a reducing gas such as hydrogen.
In the case of a pack-type filter, which comprises a filter media fitted within a confining ring or housing, the procedure is similar. The filter media is cut to be slightly undersize relative to the housing. A strip of bonding membrane having a width slightly greater than the height of the filter media is then wrapped around the filter media and the excess is trimmed off. The filter media is then compressed and forced into the housing using an arbor press or similar device.
Expansion of the filter media tends to densify the bonding membrane at all points of contact. Thereafter, the filter assembly is subjected to sintering conditions for a time suffi-cient to develop a strong, leak-free autogenous or sinter bond between the filter media and the housing through the bonding membrane.
` Thus broadly, the invention contemplates a method of joining porous metallic filter media and a metal filter housing to form a filter assembly which comprises the steps of forming a diffusion bonding porous membrane with tlle mcmbralle comprising a w~eb of small diameter metal fibrils having metal-lurgical compatability with both the filter media and the ~ ` 1078749 housing, placing the porous membrane between and in contact witll the filter medi`a and the housing to form an assembly, and sintering the assembly at a temperature below the melting point of the membrane, filter media and housing and for a time sufficient to form a strong, leak-free autogenous bond between the filter media and the housing.
Additionally the invention contemplates a filter adapted to filter fluids whi`ch comprises a solid metal housing, a metall;c filter media located in the housing, and a bonding membrane seal comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing and located there-between, with the web being autogenously bonded to the housing, : and with the filter media providing a leak-free seal between -15 the housing and the media thereby providing channeled fluid flow only through the filter media.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
The obiects and features of the invention will become more clearly apparent upon a review of the following description in conjunction with the accompanying drawing in which:
Figure 1 is an end view of a cylindrical or "pancake"
filter assembly with parts broken away and in section.
Figure 2 is a cross-sectional side view of the struc-ture of Figure 1.
_g_ ~ .
Figure 3 is a plan view of a pack-type filter assembly.
Figure 4 is a cross-sectional side view of the struc-~ ture of Figure 3.
Referring now to Figure 1, there is shown one embodi-ment of a filter assembly 10 in which one end plate 11 has been partially broken away to show the pleated configuration of filter media 12. Media 12 may comprise multiple, superposed layers of finely-woven metal screening, a sintered metal fibril web or a sintered metal fibril web faced with a relatively coarse metal screen. End plates 11 are of annular shape having an inner cylindrical wall portion or rim 13 and an outer cylindrical wall portion or rim 14. Rims 13 and 14 define an annular channel 15 into which filter media 12 fits. This is best illus-trated in Figure 2.
Filter media 12 is attached to end plates 11 by a strong, leak-free sinter bond through bonding membrane 16.
Membrane 16 comprises a flat, annular ring fabricated from a metal fibril web having metallurgical compatability with both the metallic filter media 12 and the metal end plates 11.
Figures 3 and 4 illustrate another filter assembly constructed in accordance with the teachings of this invention.
The filter assembly 20 comprises an exterior ring or housinc3 21 which confines a metallic filter media 22. As is shown in Figure 4, media 22 is preferably of folded or pleated config-uration. Media 22 wrappe~ with the bonding mcmbrane 23 is sized to produce a compressive it ~it]lin housing 21. As i thc cmbodimellt of ligure 1, filter mcdia 22 m<ly conl~risc multiple super~)osed layers of finelY-woven scrcenillg, a sintcred mctal fibril t~eb or a sintcred metal fibril wcb faced ~ith a relativcly co~rse metal screcll.
A
Bonding membrane 23 surrounds media 22 and forms a juncture between the media and housing 21. Membrane 23 comprises a strip of metal fibril web having a composition such that it will form a autogenous or sinter bond between the metallic filter media 22 and the metal housing 21. Metallurgical compatability between the media and the membrane and between the membrane and the housing is best assured by fabricating all three elements of the same metal such as the same stainless steel. The sinter bond developed between media 22 and housing 21 through membrane 23 has great phys1cal strength and provides a permanent, leak-free seal.
The following examples more clearly illustrate specific ; embodiments of the invention.
Diffusion bonding membranes were prepared from webs of stainless steel metal fibrils. The metal fibrils were ' obtained in the form of a commercially available web having nominal fibril diameters of 4, 8 and 12 microns and sold under the trade designation "Brunsmet".
Layers of the Brunsmet web were stacked together to obtain the desired membrane thickness and density. The stacked layers were then passed through a rolling mill set at a gap of .~ .
~ 0.010 inches. Thereafter, the resulting sheet was annealed in - a vacuum furnace at a temperature of about 1800F for a time at temperature of about 10 minutes. The furnace was then cooled as quickly as possible using a hydrogen purge. The annealed sheets were again rolled to a thickness of about 0.025 inches to produce a finished diffusion bonding membrane which dis-played a density of about 20% as compared to the density of an equivalent thickness of the same stainless steel. Strips and annular shapes were cut from the membrane and were used to ~, ~C378749 sinter bond stainless steel filter media to stainless steel end plates and housings to produce filter assemblies such as those illustrated in the drawing.
S A cylindrical filter assembly SUCIl as that illustrat~d in Figures 1 and 2 was constructed using the diffusion bonding membrane of Example 1 to sinter bond the filter media to the end plates. The filter media consisted of a sintered stainless steel fibril web faced on both sides with a 50 mesh stainless steel screen. The filter media was seam welded to form a continuous loop and was pleated or folded as shown in Figure 1 so as to obtain a large effective filtering area withill a relatively small space.
End plates of the same stainless steel were cleaned lS well in a solvent and a diffusion bonding membrane conforming in size and shape to the bonding surface of the end plates was placed inside one of the end plates. The pleated filter media was carefully centered on the bonding membrane and the remain-- ing end plate and bonding~membrane were then assembled. The assembly was then compressed in a punch press using a fixture to maintain concentricity and height. This pressing operation - densified the bonding membranes and tended to force the membranes into the filter media at all points of contact.
The assembly was then transferred to a vacuum sintering furnace taking care to avoid any movement of one part relative to another. Alignment of the end caps was maintained using a fixture compatible with sintering temyeratures and the assembly was weighted with approximately 5 lbs. Thereafter, the assembly was sintered for 2 hours at 2200F followed by rapid cooling using a hydrogen flush. The resulting sinter bond between the end plates and the filter media was leak-free and of great ~hysical strength.
~, i .
A pack-type filter assembly such as that illustrated in Figures 3 and 4 was constructed using the diffusion bonding mem-brane of EY~ample 1 to sinter bond the filter media to a cylin-drical housing. The filter media again consisted of a silltercd stainless steel fibril web faced on both sides with a stainless steel screen and formed in a pleated configuration as illustrated in Figure 4. The media was cut to a circular shape having a diameter slightly smallerthan the inner diameter of the stainless steel housing.
A strip of bonding membrane prepared as in Example 1 was cut to a width about 1/4 inch greater thall the media plea~
height and to a length 1/2 inch greater than twice the circum-ference of the filter media. One end of the membrane was - 15 feathered by tearing off about 1/4 inch of material. Starting with the feathered end, the bonding membrane was tightly wrapped for two full turns around the filter media. The exposed end of the membrane wrapping was also feathered by tearing off another small length of material. Excess membrane was then trimmed from the assembly màking the membrane wrap equal to the pleat height of the filter media.
The membrane wrapped filter media was then inserted in a compressed state into the housing using a die and arbor press. Thereafter, the assembly was transferred to a vacuum furnace and was sintered at 2000F for two hours. ~fter sintcring was complete, the assembly was quickly cooled using hydrogen to flush the furnace. The sintered filter assembly displ,ayed a strong, leak-free autogenous bond between the filtcr media and the housing.
It is to be understood that the specific embodiments disclosed herein are exemplary in nature. Other embodiments of 'this invention will be apparent to those havill~ ski11 in t~ drt.
~ i
from the joint area into the filter media reducing the effective filter area and often preventing the formation of uniform fillets.
Additionally, the brazing metal is of different composition than that of the filter media and of the other metal components of the filter assembly. In some corrosive environments, this will cause localized electrolytic corrosion and early failure.
Brazing also requires a short time-temperature cycle which effectively rules out furnace brazing techniques. Brazing ; of stainless steel filter media requires temperatures in excess of the oxidation point thus necessitating use of either an inert atmosphere or a protective flux. If a protective flux is used, it must be subsequently removed and this is an operation which is both costly and unreliable.
Both resistance welding and fusion welding are compli-cated by the difference in effective thickness between the filtermedia and the relatively massive metal components to which it is joined. The excessive heat employed by use of these tech-niques tends to fuse a portion of the filter media, and so reduce its effective filtering area, or to distort the metal components of the filter assembly. Heat distortion is often so extensive as to require machining of the welded assembly to obtain the desired finished dimensions. In addition, the machining step may introduce undesirable metal particulates into the downstream portion of the filter assembly.
Lastly, it has been proposed to attach metal strips over the edges of the filter media by means of crimping or welding and thereafter fusion welding the metal strip to the filter end plates. This technique is disclosed in U.S. Patent No. 3,426,910. While this joining method produces a reliable seal between the media and the other metal components making up the filter assembly, it does result in the loss of effective filter area particularly in the case of relatively short, cylin-drical filters. Moreover, this joining technique is not 10~8749 adaptable for use with a flat, or pack filter.
SUMMARY OF THE INVENTION
Metallic filter media are joined to other metal components of a filter assembly by sinter bonding the media to the metal components through a diffusion bonding membrane.
The diffusion bonding membrane comprises a web of metal fibrils which is metallurgically compatible with both the filter media ; and the other metal components. In a preferred embodiment, the filter media, the diffusion bonding membrane and the other metal components of the filter assembly are of identical compo-sition.
The diffusion bonding membrane is placed between the filter media edges and the metal components. Thereafter, the assembly is sintered, preferably in a vacuum furnace, at a .,~.; , ( 15 temperature below the melting point of the metals for a time ;'~
i sufficient to develop a sinter bond between the filter media and the bonding membrane and between the bonding membrane and ~ the other metal components of the filter assembly.
:~ Hence, it is an object of this invention to provide aprocess for the joining of metallic filter media to other metal - components.
It is another object of this invention to provide filter assemblies in which the filter media is metallurgically bonded to other metal components making up the assembly.
Yet another object of this invention is to sinter weld metallic filter media to other metal components of a filter assembly.
A specific object of this invention is to sinter bond metallic filter media to other metal components through use of a metal fibril, diffusion bonding membrane.
DISCUSSION OF THE INVENTION
Metallic filter media, including very finely-woven metal screen and sintered, metal fibril webs, may be sinter bonded to more massive metal filter components by means of a diffusion bonding membrane. The diffusion bonding membrane comprises a thin web of metal fibrils which have the ability to readily sinter to an adjoining metal part at high temperature. Composition of the metal fibrils making up the bonding membrane must be metallurgi-cally compatible with both the filter media and the metal component parts making up the finished filter assembly. By metallurgical compatibility is meant the ability to form a strong sinter or autogenous bond at a temperature where at the shape and properties of the component parts of the filter assembly are unaffected.
Metallurgical comparability is most readily obtained by using the same metal or alloy for the filter media, the bonding membrane and the other metal component parts of the assembly.
Appropriate metals for use in the filter assemblies of this invention include the stainless steels, Inconel, Hastelloy, the nickel-base super alloys and various iron, nickel and cobalt-base alloys. Of these metals, the stainless steels find the most general application.
The diffusion bonding membranes of this invention may be fabricated from the same metal fibrils as are used to manufacture sintered metal fibril webs used as filter media. The fibrils themselves may have a diameter in the range of 2-40 microns and a length in the general range of 1/2 to 6 inches. In most instances the smaller fibrils, those having a diameter of about 4 to 16 microns and a length of 1/2 to 1 inches, are preferred. The fibrils may be produced, for example, by the process described in the Webber et al patent, U.S. 3,379,000. Metal fibrils produced by other known processes may be used as well.
t A~ k --5---` ~078749 Metal fibril compacts suitable for use as the diffu~
sion bonding membranes of this invention may be fabricated from the fibrils in the following manner. First, a loose mat of uniformly dispersed, randomly oriented intertwining metal fibrils is formed. This mat is then compressed to increase its density. The compressed mat is next annealed to relieve stresses and reduce its elasticity. Thereafter, the annealed web is rolled to obtain a bonding membrane of the desired thickness. The finished shee*s or membranes display a high degree of physical integrity but must be protected against dents and nicks which could prevent proper sintering of the seal during fabrication of the filter elements.
The loose, metal fibril mats used in making bonding membranes may be prepared by introducing separated fibrils into an upwardly moving stream of high velocity air by which they are transported into contact with a downwardly-facing reticulated web. Fibrils build up on the web and form a mat of interlaced, randomly dispersed fibrils. This mat has a low density, on the order of 1% of the density of an equivalent volume of solid metal, but has sufficient strength for subsequent handling. Procedures and apparatus for mat forming are disclosed in greater detail in U.S. Patent No. 3,505,038. Additionally, metal fibril mats of a variety of metal alloys are commercially available under the trade designation, "Brunsmet Web".
It is desirable that the diffusion bonding membranes be of low to intermediate density so that they can deform suffi-ciently to conform to any irregularities of the filter media edges. At the same time, it is necessary that the membranes be sufficiently dense to provide a strong, leak-free seal. A
density in the range of about 5% to 40%, based on the density of an equiva]ent volume of solid metal, is generally appropriate.
lt is preferred that the density be in the range of about 15~, to 25%.
The diffusion bonding membranes are desirably quite ! thin, generally in the range of about 0.005 to 0.05 inches in thickness. However, membrane thickness is not particularly critical as multiple membrane layers can be used. A membrane ~; 5 thickness of 0.02 to 0.03 inches is appropriate and works well for stainless steel filter assemblies.
Fabrication and bonding techniques, using the diffu-sion bonding membranes of this invention, are quite simple. In the case of a short, cylindrical or "pancake" type filter, the filter assembly typically consists of the filter media bonded between a pair of end plates. The filter media may comprise a plurality of superposed, finely-woven screens or a sintered, metal fibril compact either alone or with relatively coarse facing or backup screens on either side of the compact.
The filter medium is preferably folded into a pleated configur-ation, formed into a cylindrical shape and welded to form a closed loop.
The diffusion bonding membrane is cut to conform in size and shape with the end caps. Final assembly is accomplished by placing a bonding membrane inside one of the end caps and carefully locating the filter media on the membrane and centered within the end cap. Care must be taken to insure that the filter media edge is in complete contact with the bonding membrane.
Thereafter, the other end cap and bonding membrane is placed on the filter media again being sure of complete contact. The assembly is then compressed as in a punch press to densify the bonding membrane and force it into the filter media at all points of contact.
Diffusion bonding of the filter media to the end caps through the bonding membrane is accomplished by sintering the assembly at a temperature below the melting point of the metals ,~ '' , for a time sufficient to form an autogenous or sinter bond.
Sintering temperature is tai`lored to the metals used in the filter assembly. Appropriate sintering temperatures for stainless steels, for example, are about 2000F to 2200F
for a time of about 1 to 3 hours. It is preferred to carry out the sintering step in a vacuum. After sintering is com-plete, it is preferred to cool the filter assen~ly quickly by backfllling the vacuum furnace with a reducing gas such as hydrogen.
In the case of a pack-type filter, which comprises a filter media fitted within a confining ring or housing, the procedure is similar. The filter media is cut to be slightly undersize relative to the housing. A strip of bonding membrane having a width slightly greater than the height of the filter media is then wrapped around the filter media and the excess is trimmed off. The filter media is then compressed and forced into the housing using an arbor press or similar device.
Expansion of the filter media tends to densify the bonding membrane at all points of contact. Thereafter, the filter assembly is subjected to sintering conditions for a time suffi-cient to develop a strong, leak-free autogenous or sinter bond between the filter media and the housing through the bonding membrane.
` Thus broadly, the invention contemplates a method of joining porous metallic filter media and a metal filter housing to form a filter assembly which comprises the steps of forming a diffusion bonding porous membrane with tlle mcmbralle comprising a w~eb of small diameter metal fibrils having metal-lurgical compatability with both the filter media and the ~ ` 1078749 housing, placing the porous membrane between and in contact witll the filter medi`a and the housing to form an assembly, and sintering the assembly at a temperature below the melting point of the membrane, filter media and housing and for a time sufficient to form a strong, leak-free autogenous bond between the filter media and the housing.
Additionally the invention contemplates a filter adapted to filter fluids whi`ch comprises a solid metal housing, a metall;c filter media located in the housing, and a bonding membrane seal comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing and located there-between, with the web being autogenously bonded to the housing, : and with the filter media providing a leak-free seal between -15 the housing and the media thereby providing channeled fluid flow only through the filter media.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
The obiects and features of the invention will become more clearly apparent upon a review of the following description in conjunction with the accompanying drawing in which:
Figure 1 is an end view of a cylindrical or "pancake"
filter assembly with parts broken away and in section.
Figure 2 is a cross-sectional side view of the struc-ture of Figure 1.
_g_ ~ .
Figure 3 is a plan view of a pack-type filter assembly.
Figure 4 is a cross-sectional side view of the struc-~ ture of Figure 3.
Referring now to Figure 1, there is shown one embodi-ment of a filter assembly 10 in which one end plate 11 has been partially broken away to show the pleated configuration of filter media 12. Media 12 may comprise multiple, superposed layers of finely-woven metal screening, a sintered metal fibril web or a sintered metal fibril web faced with a relatively coarse metal screen. End plates 11 are of annular shape having an inner cylindrical wall portion or rim 13 and an outer cylindrical wall portion or rim 14. Rims 13 and 14 define an annular channel 15 into which filter media 12 fits. This is best illus-trated in Figure 2.
Filter media 12 is attached to end plates 11 by a strong, leak-free sinter bond through bonding membrane 16.
Membrane 16 comprises a flat, annular ring fabricated from a metal fibril web having metallurgical compatability with both the metallic filter media 12 and the metal end plates 11.
Figures 3 and 4 illustrate another filter assembly constructed in accordance with the teachings of this invention.
The filter assembly 20 comprises an exterior ring or housinc3 21 which confines a metallic filter media 22. As is shown in Figure 4, media 22 is preferably of folded or pleated config-uration. Media 22 wrappe~ with the bonding mcmbrane 23 is sized to produce a compressive it ~it]lin housing 21. As i thc cmbodimellt of ligure 1, filter mcdia 22 m<ly conl~risc multiple super~)osed layers of finelY-woven scrcenillg, a sintcred mctal fibril t~eb or a sintcred metal fibril wcb faced ~ith a relativcly co~rse metal screcll.
A
Bonding membrane 23 surrounds media 22 and forms a juncture between the media and housing 21. Membrane 23 comprises a strip of metal fibril web having a composition such that it will form a autogenous or sinter bond between the metallic filter media 22 and the metal housing 21. Metallurgical compatability between the media and the membrane and between the membrane and the housing is best assured by fabricating all three elements of the same metal such as the same stainless steel. The sinter bond developed between media 22 and housing 21 through membrane 23 has great phys1cal strength and provides a permanent, leak-free seal.
The following examples more clearly illustrate specific ; embodiments of the invention.
Diffusion bonding membranes were prepared from webs of stainless steel metal fibrils. The metal fibrils were ' obtained in the form of a commercially available web having nominal fibril diameters of 4, 8 and 12 microns and sold under the trade designation "Brunsmet".
Layers of the Brunsmet web were stacked together to obtain the desired membrane thickness and density. The stacked layers were then passed through a rolling mill set at a gap of .~ .
~ 0.010 inches. Thereafter, the resulting sheet was annealed in - a vacuum furnace at a temperature of about 1800F for a time at temperature of about 10 minutes. The furnace was then cooled as quickly as possible using a hydrogen purge. The annealed sheets were again rolled to a thickness of about 0.025 inches to produce a finished diffusion bonding membrane which dis-played a density of about 20% as compared to the density of an equivalent thickness of the same stainless steel. Strips and annular shapes were cut from the membrane and were used to ~, ~C378749 sinter bond stainless steel filter media to stainless steel end plates and housings to produce filter assemblies such as those illustrated in the drawing.
S A cylindrical filter assembly SUCIl as that illustrat~d in Figures 1 and 2 was constructed using the diffusion bonding membrane of Example 1 to sinter bond the filter media to the end plates. The filter media consisted of a sintered stainless steel fibril web faced on both sides with a 50 mesh stainless steel screen. The filter media was seam welded to form a continuous loop and was pleated or folded as shown in Figure 1 so as to obtain a large effective filtering area withill a relatively small space.
End plates of the same stainless steel were cleaned lS well in a solvent and a diffusion bonding membrane conforming in size and shape to the bonding surface of the end plates was placed inside one of the end plates. The pleated filter media was carefully centered on the bonding membrane and the remain-- ing end plate and bonding~membrane were then assembled. The assembly was then compressed in a punch press using a fixture to maintain concentricity and height. This pressing operation - densified the bonding membranes and tended to force the membranes into the filter media at all points of contact.
The assembly was then transferred to a vacuum sintering furnace taking care to avoid any movement of one part relative to another. Alignment of the end caps was maintained using a fixture compatible with sintering temyeratures and the assembly was weighted with approximately 5 lbs. Thereafter, the assembly was sintered for 2 hours at 2200F followed by rapid cooling using a hydrogen flush. The resulting sinter bond between the end plates and the filter media was leak-free and of great ~hysical strength.
~, i .
A pack-type filter assembly such as that illustrated in Figures 3 and 4 was constructed using the diffusion bonding mem-brane of EY~ample 1 to sinter bond the filter media to a cylin-drical housing. The filter media again consisted of a silltercd stainless steel fibril web faced on both sides with a stainless steel screen and formed in a pleated configuration as illustrated in Figure 4. The media was cut to a circular shape having a diameter slightly smallerthan the inner diameter of the stainless steel housing.
A strip of bonding membrane prepared as in Example 1 was cut to a width about 1/4 inch greater thall the media plea~
height and to a length 1/2 inch greater than twice the circum-ference of the filter media. One end of the membrane was - 15 feathered by tearing off about 1/4 inch of material. Starting with the feathered end, the bonding membrane was tightly wrapped for two full turns around the filter media. The exposed end of the membrane wrapping was also feathered by tearing off another small length of material. Excess membrane was then trimmed from the assembly màking the membrane wrap equal to the pleat height of the filter media.
The membrane wrapped filter media was then inserted in a compressed state into the housing using a die and arbor press. Thereafter, the assembly was transferred to a vacuum furnace and was sintered at 2000F for two hours. ~fter sintcring was complete, the assembly was quickly cooled using hydrogen to flush the furnace. The sintered filter assembly displ,ayed a strong, leak-free autogenous bond between the filtcr media and the housing.
It is to be understood that the specific embodiments disclosed herein are exemplary in nature. Other embodiments of 'this invention will be apparent to those havill~ ski11 in t~ drt.
~ i
Claims (23)
1. A method of joining porous metallic filter media and a metal filter housing to form a filter assembly which comprises the steps of:
forming a diffusion bonding porous membrane, said membrane comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing;
placing said porous membrane between and in contact with the filter media and the housing to form an assembly; and sintering said assembly at a temperature below the melting point of the membrane, filter media and housing and for a time sufficient to form a strong, leak-free autogenous bond between the filter media and the housing.
forming a diffusion bonding porous membrane, said membrane comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing;
placing said porous membrane between and in contact with the filter media and the housing to form an assembly; and sintering said assembly at a temperature below the melting point of the membrane, filter media and housing and for a time sufficient to form a strong, leak-free autogenous bond between the filter media and the housing.
2. The method of Claim 1 wherein said metal fibrils have a diameter in the range of 2 to 40 microns and a length in the range of 1/2 to 6 inches.
3. The method of Claim 2 wherein said membrane has a density in the range of 5% to 40% based on the density of an equivalent volume of solid metal.
4. The method of Claim 3 wherein said membrane has a thickness in the range of 0.005 to 0.05 inches.
5. The method of Claim 1 wherein the composition of said metal fibrils is selected from the group consisting of the stainless steels, Inconelx, Hastelloyx, nickel-base super alloys and iron, cobalt and nickel-base alloys.
x TRADE MARK
x TRADE MARK
6. The method of Claim 4 wherein the composition of said metal fibrils is selected from the group consisting of the stainless steels, Inconel, Hastalloy, nickel-base super alloys and iron, cobalt and nickel-base alloys.
7. The method of Claim 4 wherein said filter media comprises a sintered metal fibril web.
8. The method of Claim 7 wherein said bonding membrane, said filter media and said housing are fabricated of the same metal.
9. The method of Claim 8 wherein said sintering is performed under vacuum for a time in the range of 1 to 3 hours at a temperature in the range of 2000 to 2200°F.
10. The method of Claim 9 wherein said metal fibrils have a diameter in the range of 4 to 16 microns and wherein the density of said membrane is in the range of 15% to 25%
based on the density of an equivalent volume of solid metal.
based on the density of an equivalent volume of solid metal.
11. The method of Claim 8, Claim 9 or Claim 10 wherein said metal is stainless steel.
12. A filter adapted to filter fluids comprising:
(a) a solid metal housing and;
(b) a metallic filter media located in the housing; and (c) a bonding membrane seal comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing and located therebetween, the web autogenously bonded to the housing and the filter media providing a leak-free seal between the housing and the media thereby providing channeled fluid flow only through the filter media.
(a) a solid metal housing and;
(b) a metallic filter media located in the housing; and (c) a bonding membrane seal comprising a web of small diameter metal fibrils having metallurgical compatability with both the filter media and the housing and located therebetween, the web autogenously bonded to the housing and the filter media providing a leak-free seal between the housing and the media thereby providing channeled fluid flow only through the filter media.
13. The filter of Claim 12 wherein said metal fibrils have a diameter in the range of 2 to 40 microns and a length in the range of 1/2 to 6 inches.
14. The filter of Claim 13 wherein said membrane has a porosity in the range of 60% to 95% and a thickness in the range of 0.005 to 0.05 inches.
15. The filter of Claim 12, Claim 13 or Claim 14 wherein said filter media comprises multiple superposed layers of finely woven metal screen of the same composition as said membrane and arranged in a pleated configuration.
16. The filter of Claim 12 wherein said filter media comprises sintered metal fibril web of the same composition as said membrane and arranged in a pleated configuration.
17. The filter of Claim 14 wherein said filter media comprises sintered metal fibril web of the same composition as said membrane and arranged in a pleated configuration.
18. The filter of Claim 16 or Claim 17 wherein said metal fibril web is faced on both sides with a coarser woven screen.
19. The filter of Claim 12 Claim 13 or Claim 14 wherein said filter media is cylindrical in shape and is arranged in a pleated configuration and wherein a pair of end plates are autogenously bonded to the media ends through said diffusion bonding membrane.
20. The filter of Claim 12 wherein said filter media is of circular disc shape contained within and autogenously bonded to a cylindrical metal housing.
21. The filter of Claim 13 wherein said filter media is of circular disc shape contained within and autogenously bonded to a cylindrical metal housing.
22. The filter of Claim 14 wherein said filter media is of circular disc shape contained within and autogenously bonded to a cylindrical metal housing.
23. The filter of Claim 20, Claim 21 or Claim 22 wherein said filter media is arranged in a pleated configuration.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/758,130 US4114794A (en) | 1977-01-10 | 1977-01-10 | Method of autogenously bonding filter assemblies |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078749A true CA1078749A (en) | 1980-06-03 |
Family
ID=25050621
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA291,843A Expired CA1078749A (en) | 1977-01-10 | 1977-11-28 | Autogenously bonded filter assemblies and method of bonding same |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4114794A (en) |
| JP (2) | JPS5852750B2 (en) |
| BE (1) | BE859222A (en) |
| CA (1) | CA1078749A (en) |
| DE (1) | DE2756179C2 (en) |
| FR (1) | FR2376681A1 (en) |
| GB (1) | GB1576960A (en) |
| IT (1) | IT7847543A0 (en) |
| NL (1) | NL7800291A (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4488966A (en) * | 1980-01-24 | 1984-12-18 | Brunswick Corporation | Filter pleat support means |
| US4290889A (en) * | 1980-01-24 | 1981-09-22 | Brunswick Corporation | Support for backflushable filter media |
| EP0187358A3 (en) * | 1984-12-24 | 1987-03-18 | Kurashiki Boseki Kabushiki Kaisha | Filter element and its production |
| US4687579A (en) * | 1986-05-02 | 1987-08-18 | The United States Of America As Represented By The United States Department Of Energy | Sintered composite medium and filter |
| CA1309954C (en) * | 1987-07-29 | 1992-11-10 | Yasuo Yamada | Deaerator for particulates |
| DE8901381U1 (en) * | 1989-02-07 | 1989-03-30 | Siemens Ag, 1000 Berlin Und 8000 Muenchen, De | |
| DE8905452U1 (en) * | 1989-04-29 | 1989-08-10 | Leybold Ag, Zweigniederlassung Koeln, 5000 Koeln, De | |
| US5512076A (en) * | 1990-07-14 | 1996-04-30 | Gibson; Glenville | Filter apparatus |
| US5238477A (en) * | 1992-01-06 | 1993-08-24 | Layton Howard M | Hepa filter unit having a metallic membrane |
| US5158586A (en) * | 1992-01-06 | 1992-10-27 | Layton Howard M | Hepa filter unit having a metallic membrane |
| US5545323A (en) * | 1993-09-28 | 1996-08-13 | Pall Corporation | Filter assembly and method of making a filter assembly |
| CN1201442A (en) * | 1995-11-09 | 1998-12-09 | 梅姆特克美国有限公司 | Back-flushing filter cartridge and method of back-flushing same |
| AU8064898A (en) * | 1997-06-10 | 1998-12-30 | Usf Filtration And Separations Group Inc. | Fluid filter and method of making |
| US6096212A (en) * | 1997-06-10 | 2000-08-01 | Usf Filtration And Separations Group, Inc. | Fluid filter and method of making |
| US6435861B1 (en) | 1997-06-10 | 2002-08-20 | Usf Filtration And Separations Group, Inc. | Gas burner assembly and method of making |
| US6291806B1 (en) | 1998-10-01 | 2001-09-18 | Usf Filtration And Separations Group, Inc. | Process for bonding workpieces |
| US6180909B1 (en) * | 1998-10-01 | 2001-01-30 | Usf Filtration And Separations Group, Inc. | Apparatus and method for sealing fluid filter by infrared heating |
| CA2397928A1 (en) * | 2000-02-23 | 2001-08-30 | N.V. Bekaert S.A. | Filter element |
| JP4900989B2 (en) * | 2000-04-06 | 2012-03-21 | 富士フィルター工業株式会社 | Backwashable gas dust collector |
| KR20050014824A (en) * | 2002-05-27 | 2005-02-07 | 칸사이 카나아미 가부시키가이샤 | Filter unit for highly viscous fluid and spinning pack |
| US8727203B2 (en) | 2010-09-16 | 2014-05-20 | Howmedica Osteonics Corp. | Methods for manufacturing porous orthopaedic implants |
| US20150238884A1 (en) * | 2014-02-27 | 2015-08-27 | Delta Screen & Filtration, Llc | Composite Filter Assembly and Method |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2547857A (en) * | 1947-11-10 | 1951-04-03 | Sackner Prod Inc | Lubricant filter |
| US3165473A (en) * | 1960-10-24 | 1965-01-12 | Pall Corp | Corrugated filter unit |
| US3505038A (en) * | 1964-08-24 | 1970-04-07 | Brunswick Corp | Metal fibril compacts |
| US3426910A (en) * | 1965-01-04 | 1969-02-11 | John P Winzen | Pleated metallic filter element |
| US3437457A (en) * | 1965-04-13 | 1969-04-08 | Huyck Corp | Reinforced metal fiber composites |
| US3690606A (en) * | 1968-05-27 | 1972-09-12 | Pall Corp | Anisometric compressed and bonded multilayer knitted wire mesh composites |
| US3501013A (en) * | 1968-11-07 | 1970-03-17 | Bendix Corp | Filter assembly and method of manufacturing same |
| DE1958116A1 (en) * | 1968-11-21 | 1970-06-11 | Carborundum Co | Filter |
| US3680183A (en) * | 1971-03-18 | 1972-08-01 | David R Johnson | Machines for making metal fibril compacts |
| US3984044A (en) * | 1973-10-01 | 1976-10-05 | Composite Sciences, Inc. | Retention means for mechanical separation and process of making same |
| DE2536276C3 (en) * | 1975-08-14 | 1978-03-09 | Sintermetallwerk Krebsoege Gmbh, 5608 Radevormwald | Process for the production of a filter cartridge made of sintered metal |
-
1977
- 1977-01-10 US US05/758,130 patent/US4114794A/en not_active Expired - Lifetime
- 1977-09-30 BE BE2056300A patent/BE859222A/en not_active IP Right Cessation
- 1977-11-28 CA CA291,843A patent/CA1078749A/en not_active Expired
- 1977-12-01 GB GB50110/77A patent/GB1576960A/en not_active Expired
- 1977-12-14 FR FR7737641A patent/FR2376681A1/en active Granted
- 1977-12-16 DE DE2756179A patent/DE2756179C2/en not_active Expired
- 1977-12-20 JP JP52153513A patent/JPS5852750B2/en not_active Expired
-
1978
- 1978-01-06 IT IT7847543A patent/IT7847543A0/en unknown
- 1978-01-10 NL NL7800291A patent/NL7800291A/en not_active Application Discontinuation
-
1982
- 1982-05-26 JP JP57089567A patent/JPS5834011A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS618730B2 (en) | 1986-03-17 |
| NL7800291A (en) | 1978-07-12 |
| DE2756179C2 (en) | 1982-11-18 |
| JPS5388273A (en) | 1978-08-03 |
| IT7847543A0 (en) | 1978-01-06 |
| DE2756179A1 (en) | 1978-07-13 |
| BE859222A (en) | 1978-01-16 |
| FR2376681B1 (en) | 1981-07-24 |
| FR2376681A1 (en) | 1978-08-04 |
| US4114794A (en) | 1978-09-19 |
| GB1576960A (en) | 1980-10-15 |
| JPS5852750B2 (en) | 1983-11-25 |
| JPS5834011A (en) | 1983-02-28 |
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