WO2008146045A1 - Filtres coalesceurs améliorés - Google Patents
Filtres coalesceurs améliorés Download PDFInfo
- Publication number
- WO2008146045A1 WO2008146045A1 PCT/GB2008/050387 GB2008050387W WO2008146045A1 WO 2008146045 A1 WO2008146045 A1 WO 2008146045A1 GB 2008050387 W GB2008050387 W GB 2008050387W WO 2008146045 A1 WO2008146045 A1 WO 2008146045A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- oil
- layer
- filter
- coalescing
- fibers
- Prior art date
Links
- 239000000463 material Substances 0.000 claims abstract description 31
- 230000005484 gravity Effects 0.000 claims abstract description 5
- 239000000835 fiber Substances 0.000 claims description 57
- 229920001410 Microfiber Polymers 0.000 claims description 13
- 239000003658 microfiber Substances 0.000 claims description 13
- 239000004744 fabric Substances 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 10
- 239000011521 glass Substances 0.000 claims description 6
- 229910010272 inorganic material Inorganic materials 0.000 claims description 2
- 239000011147 inorganic material Substances 0.000 claims description 2
- 238000003466 welding Methods 0.000 abstract description 11
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 239000003921 oil Substances 0.000 description 42
- 229920000728 polyester Polymers 0.000 description 19
- 238000000465 moulding Methods 0.000 description 12
- 229920005989 resin Polymers 0.000 description 11
- 239000011347 resin Substances 0.000 description 11
- 239000011148 porous material Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000005388 borosilicate glass Substances 0.000 description 6
- -1 alkylene glycol Chemical compound 0.000 description 5
- 239000000356 contaminant Substances 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N ethylene glycol Natural products OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229920001778 nylon Polymers 0.000 description 4
- 238000004826 seaming Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000004677 Nylon Substances 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000000443 aerosol Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000006260 foam Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000000049 pigment Substances 0.000 description 3
- 229920000139 polyethylene terephthalate Polymers 0.000 description 3
- 239000005020 polyethylene terephthalate Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229920005822 acrylic binder Polymers 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 2
- 239000008263 liquid aerosol Substances 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 229920001568 phenolic resin Polymers 0.000 description 2
- 239000005011 phenolic resin Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000009958 sewing Methods 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000012815 thermoplastic material Substances 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- YJVBLROMQZEFPA-UHFFFAOYSA-L acid red 26 Chemical compound [Na+].[Na+].CC1=CC(C)=CC=C1N=NC1=C(O)C(S([O-])(=O)=O)=CC2=CC(S([O-])(=O)=O)=CC=C12 YJVBLROMQZEFPA-UHFFFAOYSA-L 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 238000004887 air purification Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011118 depth filtration Methods 0.000 description 1
- 150000005690 diesters Chemical class 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000005374 membrane filtration Methods 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- KYTZHLUVELPASH-UHFFFAOYSA-N naphthalene-1,2-dicarboxylic acid Chemical compound C1=CC=CC2=C(C(O)=O)C(C(=O)O)=CC=C21 KYTZHLUVELPASH-UHFFFAOYSA-N 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000009999 singeing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000004758 synthetic textile Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000004753 textile 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
- B01D46/24—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
- B01D39/00—Filtering material for liquid or gaseous fluids
-
- 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
-
- 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
-
- 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
- B01D46/0027—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions
- B01D46/003—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions including coalescing means for the separation of liquid
- B01D46/0031—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions including coalescing means for the separation of liquid with collecting, draining means
-
- 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
- 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
- B29C65/08—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using ultrasonic vibrations
-
- 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
- B29C66/1142—Single butt to 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
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
- B29C66/432—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms
- B29C66/4322—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms by joining a single sheet to itself
Definitions
- the present invention relates to an improved coalescing filter and to its use for the removal of oil droplets from an air or gas stream.
- a stream may, for example, be an oil or gas stream from an oil-lubricated compressor which may be of the rotary vane or the screw type, may be from a vacuum pump or may be traveling along an air or gas line having provision for line filtration.
- a filter removes solid particles from an air stream via a matrix whilst a separator causes sub-microscopic liquid aerosols to coalesce into larger droplets that can be collected and drained.
- An efficient separator allows droplets to be retrained without being re-entrained into the air stream whilst allowing oil to drain away fast enough to prevent an undesirable increase in pressure.
- primary separation filters coalescing filters
- Coalescing filters are also commonly fitted to vacuum pumps for purifying the air stream from the exhaust side of the pump.
- the filter is likely to be challenged by a stream of air containing oil in the form of an aerosol of particle size 0.01-50 ⁇ m, though the filter may also be arranged for fluid flow in an out- to-in direction.
- the air stream is usually passed in an in-to out direction through a tubular filter having two working components, a layer within which the oil droplets coalesce and a drainage layer which collects the oil leaving the coalescing layer and retains it until it drips by gravity from the filter.
- the coalescing layer may be of borosilicate glass microfibers (see GB-A-1603519, the disclosure of which is incorporated herein by reference).
- the drainage layer may be provided by a porous sleeve of plastics foam or by a non-woven fabric.
- Coalescing filters may be used with their axes vertical or horizontal.
- Coalescing filters commonly spend their service lives wetted out with oil, and the problem of production of secondary aerosols from such filters is disclosed, for example, in GB-A-2177019 (Pall Corporation).
- One avenue of research has been to try to reduce oil-carry-over from a coalescing filter by improving the drainage layer.
- a known drainage layer material with low carry-over is an open-celled polyurethane foam having about 60 pores/inch and a PVC coating to provide resistance to chemical attack.
- the layer may also be colored with a dye or pigment to indicate the grade of filter.
- the material has the advantage that its pore structure can be made very uniform which assists drainage and reduces the tendency for oil blisters to form in the exterior of the drainage layer which can be expanded and burst by the stream of compressed air.
- the properties of the material are poor. Its maximum working temperature is 6O 0 C whereas for many applications an ability to withstand 12O 0 C is necessary. It has poor resistance to contaminants in the oil and is attacked by some of the newer diester synthetic oils. It is easily damaged through handling and becomes brittle on exposure to UV light.
- a practical embodiment of that invention employs a drainage layer of an non -woven fabric which is a 50:50 blend of nylon (3.3 d.tex) and polyester (5.3 d.tex) with an acrylic binder and fiuorochemical finish.
- the weight of the drainage layer is 252 g/m 2 and thickness 3.2-3.5mm.
- this material has limitations arising from the way in which it is made.
- the fibers are formed into a web which is subsequently heavily needled, after which it is dipped into an acrylic binder and finally passed through a fiuorochemical dip in order to reduce the surface energy of the resulting structure.
- the heavy needling leaves visible holes in the fabric.
- oil emerges through the holes and forms droplets at the surface of the fabric which become exploded by the following stream of air, causing oil re-entrainment and poor separation performance.
- a coalescing filter whose drainage layer is simple to make, in use gives air with low oil carryover, can be operated a temperatures above 6O 0 C, and is resistant to light and to chemical attack is disclosed in our EP-B-0177756, the contents of which are also incorporated herein by reference.
- That specification discloses a filter for coalescing droplets of oil in a stream of gas, comprising an oil coalescing layer of a microfibrous material and a second layer of an oil drainage material located downstream of the first layer, said drainage layer being for receiving oil from the coalescing layer and providing a path for oil to flow by gravity from the filter, characterized in that the drainage layer is a non-woven felt or wadding thermally bonded by fusible bi-component fibers.
- the formation of a welded seam in a polyester layer of a filter is disclosed in
- the polyester layer (whose construction is not disclosed) is not required to be of a construction such that oil can drain circumferentially through it, the intended use of the filter for membrane filtration being remote from the field of oil coalescence and the intended flow through the polyester layer being purely radial.
- the polyester layer is sandwiched between a cellulose acetate membrane and an outer supporting sleeve, and there is no disclosure or suggestion that the polyester layer should be an unsupported outer layer or that there should be used a material in which the structure is held together by a small proportion of fusible fibers incorporated into the web.
- a problem with which the invention is concerned is to produce a further filter having a further advantageous combination of properties, in particular a drainage layer which is easy to manufacture and has low oil carry-over.
- a tubular filter for coalescing droplets of oil in a stream of gas comprising an oil coalescing layer of a microfibrous material and a second layer of an oil drainage material located downstream of the first layer, said drainage layer being for receiving oil from the coalescing layer and providing a path for oil to flow by gravity from the filter, characterized in that the drainage layer is a butt-welded tubular structure.
- the invention also includes an oil-lubricated compressor or vacuum pump provided with an oil-coalescing filter as aforesaid.
- the invention further provides a process for purifying air from an oil lubricated compressor or vacuum pump which comprises passing the air through a coalescing filter as aforesaid. It yet further provides a drainage layer for the above filter, comprising fabric at least partially of heat-fusible material butt-welded to form a tube.
- Fig. 1 is a view in isometric projection and obliquely from above of a filter according to the invention
- a coalescing filter or separator for compressed air causes sub-microscopic liquid aerosols to coalesce into larger droplets that drain away from the air stream.
- An efficient separator allows droplets to be retrained without being re-entrained whilst allowing oily liquid to drain away fast enough to prevent an increase in pressure.
- the coalescing filter may be of external diameter 50-150 mm, internal diameter 25-100 mm, height 50-500 mm and rated flow of 0.3-5 M 3 /min.
- a filter 10 is of generally conventional structure and comprises first and second end caps 12, 16 with an inlet 14 in the first end cap.
- First and second foraminous tubular members 17, 18 e.g. of steel have between a coalescing layer 20 of pleated borosilicate glass microfiber (see GB-A- 1557821, the disclosure of which is incorporated herein by reference) and on the outer surface of the outer foraminous member 18 a drainage layer 22.
- the filters preferably have end caps 12, 16 which have low affinity for contaminants, and glass-filled nylon which has an undesirably high affinity for water is advantageously not used, PBT or other polyester or metal being preferable end cap material.
- the foraminous tubular members, coalescing layer and drainage layer are attached to the end caps by adhesive 24, 26 and the upper end cap is formed with a groove for receiving an O-ring 28 for sealing to a filter housing when the cartridge is screwed into position.
- the drainage layer comprises heat-fusible fibers butt -welded as at 30.
- the coalescing layer 20 may be of glass microfibers or other inorganic material, e.g. borosilicate glass microfibers and may be moulded, wrapped or pleated. It may also be of organic microfibers e.g. polyester fibers. In the disclosed embodiment the coalescing layer is of pleated glass microfiber, but in alternative embodiment it may be a molding in borosilicate glass microfibers. In embodiments of the invention the coalescing layer is a molding in borosilicate glass microfibres as described in our GB-A-1603519 and US-A-4303472, the disclosures of which are incorporated herein by reference.
- a method for forming a tubular filter element which includes the steps of: (a) forming a slurry of fibers in a liquid; (b) introducing the slurry under pressure into the top of an annular molding space defined between a central core, a vertical cylindrical screen spaced from and outward of said core and a support defining a lower boundary for the molding space so that a mass of fibers becomes compacted on the screen and liquid is discharged from the molding space through the screen; (c) progressively increasing the height of the effective open area of the cylindrical screen by moving upwardly a sleeve in sliding contact with the cylindrical screen at a rate substantially equal to the rate at which the height of the mass of fibers increases above the support; and (d) removing the resulting tubular mass of fibers from the molding space.
- the filter element comprises a mass of borosilicate glass microfibres bounded by a foraminous outer support sheet e.g. of steel mesh with an open area of 45-70%.
- the borosilicate fibers are dispersed in water in a blending tank under mechanical agitation, and an acid, e.g. hydrochloric or sulfuric acid is added to give a pH of 2.9-3.1 at which the dispersion is stable, the fiber to water ratio being 0.01 - 0.5 wt%, typically 0.05 wt%.
- the resulting slurry is introduced into the molding space under a pressure of typically 414-689 millibar (6-10 p.s.i). and molded as described above.
- the sleeve is raised progressively at substantially the same rate as that at which the height of the fiber mass increases in order to maintain a flow of the dispersion to the point where the mass of fibers is building up, after which air may be passed through the molded element to reduce the content of residual water.
- the formed filter element is removed from the molding space, oven dried, resin impregnated and heated to harden the resin.
- the resin may be e.g. a silicone or an epoxy resin and may be impregnated in a solvent such as acetone, but it is now in some embodiments preferred that the resin should be a phenolic resin which may be impregnated as an aqueous solution.
- the fibers in a finished filter element produced by the above method are predominantly layered in planes perpendicular to the direction in which the dispersion flows into the molding space, and the same packing pattern arises throughout the range of forming pressures that can be used in practice.
- This non-random packing pattern results in a filter element that provides efficient depth filtration and has an advantageous combination of properties including high burst strength and low pressure drop.
- the molded tubular elements may be bonded to end caps to complete the formation of the filter.
- the resin used may be an acrylate, see WO 2007/088398, the disclosure of which is incorporated herein by reference. That reference describes and claims inter alia a method of moulding a filter, which comprises the steps of: forming a tubular article from an aqueous dispersion comprising glass micro-fibers and a water-soluble acid-based resin binder comprising a carboxylated acrylic polymer and a polyfunctional alcohol; and heating the article to successively drive off water and cure the resin.
- the above process has been used e.g. to manufacture air/oil separators designed to remove oil mist generated in screw or sliding vane compressors or in vacuum pumps where the size of the particles generated lies in the range 0.3-1.5 microns ( ⁇ m) and also to manufacture in-line filters for removing oil, water and contaminants from a stream of compressed air.
- the drainage layer is normally an unsupported outer layer of the filter. It may have a weight of 100-300g/m 2 , typically about 200g/m 2 , and a thickness of about 2- 7mm, typically about 5mm.
- the fibers of the drainage layer advantageously have minimal intra-fiber and inter- fiber affinity for oil or other contaminants, and can be formed into a dimensionally stable felt or wadding of reproducible pore size with little or no needling.
- nylon fibers which absorb water
- the drainage layer comprises inert e.g. polyester fibers only.
- the polyester fibers may have a softening temperature of at least 18O 0 C and a melting temperature of at least 25O 0 C.
- polyester fibers can be formed by melt extrusion and are commonly obtained from an aromatic dicarboxylic acid (e.g., terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, etc.) and an alkylene glycol (e.g., ethylene glycol, propylene glycol, etc.) as the diol component.
- the polyester comprises at least 85 mole percent of polyethylene terephthalate fibers .
- the polyester fibers may be of non-circular cross-section and may be lobed or striated being e.g. bilobal, trilobal, tetralobal, heptalobal or of more complex non-cylindrical shapes.
- the fibers of the drainage layer should be fibers which are wholly or partly fusible, e.g. bi-component thermally bondable fibers. If the proportion of bi-component or other fusible fibers is less than 5%, there is little bonding, whereas if there are more than 25% the bonded fabric becomes very stiff. We have found that with minimal needling and thermal bonding the resulting fabric has a generally uniform pore size which reduces or prevents preferential local oil through- flow.
- the predominant polyethylene terephthalate fibers are blended with binder fibers of polyethylene isophthalate which melt about 4O 0 C to 5O 0 C below the melting temperature of the polyethylene terephthalate fibers.
- binder fibers of polyethylene isophthalate which melt about 4O 0 C to 5O 0 C below the melting temperature of the polyethylene terephthalate fibers.
- the drainage layer material may on its intended outer face be subjected to a conventional treatment intended to reduce outwardly projecting fibers which provide return paths for oil to the air stream. Such treatments include application of resin and surface heating or singeing, but obstruction of the exit pores of the drainage layer should be avoided.
- the material may also incorporate a dye or pigment for identification purposes.
- Embodiments of the drainage layer are resistant to the stress of pulses of air and are resistant to contact e.g. from the user's fingers, whereas a foam drainage layer exhibits poor resistance to such contact.
- the majority fibers of the drainage layer may comprise polyester fibers of more than about 6 d.tex, and suitable fibers currently available are of sizes 7, 17 and 24 d.tex, of which the 17 d.tex size has been found in some embodiments to give the best results, the 7 d.tex fiber size giving a smaller pore structure in which oil may be retained by capillary action. Polyester fibers have been been found to combine the properties of quick absorption of oil droplets into the material, ability to absorb a large mass of oil, quick oil drainage, and low final retention mass leading to a low final wet-band height when the resulting filter is in use.
- the bicomponent fibers which are preferred for use in the drainage layer have a relatively high -melting core and a lower -melting sheath e.g. a core which melts at above about 200 0 C and a sheath which melts at about 110-175 0 C. They may comprise about 10 wt % of the fibers of the drainage layer.
- the felt or wadding may be obtained by forming a loose web of the fibers, and passing the loose web between heated rollers so as to form a structure of an intended thickness and pore size, and it need not contain fluorocarbon.
- the minority bi-component fibers may be of the same chemical composition as the majority fibers of the drainage layer, or they may be of different composition.
- the bi-component thermally bondable fibers may be polyester fibers of the same diameter as the remaining fibers.
- a suitable drainage layer may be made from a 200 g/m 2 thermally bonded 17 d.tex polyester needlefelt (available from Lantor (UK) Limited) crushed to a thickness of 5mm and formed into a sleeve which fits over the coalescing layer.
- the following other heat-fusible fibers which are smaller than the majority fibers may be suitable:
- a fabric for a drainage layer may be made from 85 wt % of 17 d.tex polyester fibers and 15 wt% of any of the fibers (a) to (c) above, the fiber mixture being carded, crossfolded, needled, sprayed by means of a spray line successively with nitrile rubber (Synthomer 5046), resin (BT 336, BIP Resins) and colourant (CI. pigment Red 101), and passed through an oven to cure the resin.
- the fabric may be formed into a tube for pulling over the interior portions of a filter using an ultrasonic welding machine e.g. a Pfaff Seamsonic 8310 (Trade Mark) machine.
- Ultrasonic seam welding of thermoplastic materials has been known at least sunce the publication in 1966 of US-A-3242029 (Deans). That specification discloses ultrasonic sealing means in the form of a transducer element having a rotating tool operatively coupled thereto, the rotating tool beiung adapted to cooperate with an anvil which may be stationary or may rotate in synchronism with the rotating tool.
- the apparatus is disclosed as being suitable for use with films of plastics and also of synthetic fabrics e.g. of nylon.
- an ultrasonic seaming apparatus comprising a seaming station including an anvil, an electro-acoustic transducer having a resonator disposed opposite the anvil and defining with the anvil a nip through which a workpiece to be seamed is fed, means for feeding the workpiece through the seaming station at adjustable feed rates, and means couopling the feeding means to a source of electrical energy for controlling the velocity of the resonator in response to the feed rate of the workppiece.
- US-A-3852144 discloses a seaming machine which ultrasonically fuses or bonds two or more layers of thermoplastic material together in a manner similar to a sewing machine and includes means for cutting and fusing the material in a marginal portion adjacent the seam.
- ultrasonic means are provided to effect a longitudinal seam and additional means are provided to simultaneously cut and fuse the material adjacent the seamed area. In this manner it is possible to fabricate completely finished articles wherein the folded seam or hem usually deemed necessary to provide an acceptable finished appearance can be omitted.
- One machine that may be used is a Pfaff 8310-042 ultrasonic seam welding machine in which a workpiece is held between the sonotrode and the anvil wheel and welded continuously under pressure.
- t he material to be welded will be subjected to rapid changing pressure vibrations. The heat develops because of molecular vibrations beneath the material surface, for thin materials within the immediate vicinity of the actual weld.
- the machine further combines the physical procedures of welding and cutting using a V-wheel, which seams and cuts in a single operation.
- the material itself will be fed from a roll via a 'folder' (a metal, teardrop shaped device which takes the flat material, and doubles it over to present it to the welding machine with the two edges together ready for welding).
- the present arrangement provides in production quicker and more accurate seams for the drainage layer, and the seams are smaller than sewn seams and neater in appearance so that the appearance of the resulting filter is improved. Because of the reduced bulk of a welded seam compared to a sewn seam, the drainage layer can be inserted into a filter end cap over a greater range of sizes of filter than with a sewn seam. Oil carry-over is in most instances comparable to that with a sewn seam.
- a tubular microfiber coalescing element is made based on glass microfibers of diameter 0.5-10 ⁇ m and aspect ratio 500:1 - 4000:1 using the moulding procedure of our GB-A- 1603519.
- the element has an inside diameter of 75mm, an outside diameter of 95mm and a length of 250mm. It is impregnated with a phenolic resin and cured in an oven, after which the ends are sanded flat.
- a drainage layer is formed by pulling over an outer drainage layer constructed from Lantor 7239 (polyester bi-component non- woven fleece material) and formed into a tube by an ultrasonic butt weld. This gives a drainage tube with a very narrow seam width (l-3mm e.g.
- the drainage layer when inspected by eye, has a uniform appearance without visible holes from needling.
- the resulting tubular structure is fitted with steel end caps to form a filter element for in-to-out air or gas through-flow.
- the filter element is placed with its axis horizontal in a filter housing and is challenged with air from an oil- lubricated rotary vane compressor. Aerosol carryover is a measurement of how much contaminated air leaves the pump, hence an important factor when considering filter efficiency. From tests, it is found that the prototype described herein shows effective results.
- the filter may also be used with its axis vertical instead of horizontal, e.g. as described in GB-B-2261830.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Filtering Materials (AREA)
Abstract
La présente invention concerne un filtre capable d'assurer la coalescence de gouttelettes d'huile dans un flux de gaz, comprenant une couche, constituée d'un matériau microfibre, assurant la coalescence de l'huile et une seconde couche, constituée d'un matériau capable de drainer de l'huile, située en aval de la première couche et en contact direct avec elle. La couche capable de drainer de l'huile est destinée à recevoir l'huile en provenance de la couche assurant la coalescence et à servir de passage à l'huile pour qu'elle s'écoule par gravité hors du filtre. Pour faciliter la fabrication et éviter que l'huile y soit retenue, le manchon de drainage comporte une couture soudée bord à bord, par exemple d'une épaisseur de 1 à 3 mm, réalisée au moyen d'une machine à souder par ultrasons.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0710151A GB2449846A (en) | 2007-05-29 | 2007-05-29 | A coalescing filter |
GB0710151.2 | 2007-05-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2008146045A1 true WO2008146045A1 (fr) | 2008-12-04 |
Family
ID=38265431
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2008/050387 WO2008146045A1 (fr) | 2007-05-29 | 2008-05-29 | Filtres coalesceurs améliorés |
Country Status (2)
Country | Link |
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GB (1) | GB2449846A (fr) |
WO (1) | WO2008146045A1 (fr) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102172509A (zh) * | 2011-01-25 | 2011-09-07 | 太原理工大学 | 一种细粒煤的超声电解脱水方法 |
CN104383755A (zh) * | 2014-10-08 | 2015-03-04 | 何茂林 | 一种油气过滤滤芯及油气分离方法 |
EP2918939A1 (fr) * | 2014-03-14 | 2015-09-16 | BERNER INTERNATIONAL GmbH | Cartouche filtrante pour une hotte de sécurité et hotte de sécurité dotée d'au moins une cartouche filtrante |
US9144760B2 (en) | 2012-07-03 | 2015-09-29 | The University Of Akron | Liquid drainage from coalescing filter medium with drainage channels |
AT14696U1 (de) * | 2014-09-15 | 2016-04-15 | Ge Jenbacher Gmbh & Co Og | Filter |
WO2017093441A1 (fr) * | 2015-12-01 | 2017-06-08 | Ateliers Busch Sa | Pompe a vide avec element filtrant |
CN108712926A (zh) * | 2016-03-01 | 2018-10-26 | Smc株式会社 | 过滤器元件 |
WO2024003544A1 (fr) | 2022-06-29 | 2024-01-04 | Psi Global Ltd | Silencieux de filtre |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2583692A (en) | 2019-02-28 | 2020-11-11 | Psi Global Ltd | Filter cartridge and casing |
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DE1782329A1 (de) * | 1967-08-17 | 1971-08-12 | Norgren Ltd C A | Luftfiltervorrichtung |
WO1989007484A1 (fr) * | 1988-02-17 | 1989-08-24 | Process Scientific Innovations Limited | Filtre de coalescence d'huile |
US5814118A (en) * | 1996-11-18 | 1998-09-29 | Nuclear Filter Technology, Inc. | HEPA filter for venting chambers |
US6332987B1 (en) * | 1996-09-30 | 2001-12-25 | Pall Corporation | Elements and methods for coalescing a discontinuous phase of a fluid from a continuous phase |
WO2005049177A1 (fr) * | 2003-11-17 | 2005-06-02 | Donaldson Company, Inc. | Dispositif separateur permettant de separer les gaz et les liquides et procedes correspondants |
Family Cites Families (2)
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US4022249A (en) * | 1974-07-03 | 1977-05-10 | Wafilin B.V. | Fibrous tube for membrane filtration with a tearing member |
US5653833A (en) * | 1996-07-25 | 1997-08-05 | Memtec America Corporation | Method for integrally joining preformed thermoplastic core elements especially adapted for the continuous manufacture of melt-blown filter cartridges |
-
2007
- 2007-05-29 GB GB0710151A patent/GB2449846A/en not_active Withdrawn
-
2008
- 2008-05-29 WO PCT/GB2008/050387 patent/WO2008146045A1/fr active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1782329A1 (de) * | 1967-08-17 | 1971-08-12 | Norgren Ltd C A | Luftfiltervorrichtung |
WO1989007484A1 (fr) * | 1988-02-17 | 1989-08-24 | Process Scientific Innovations Limited | Filtre de coalescence d'huile |
US6332987B1 (en) * | 1996-09-30 | 2001-12-25 | Pall Corporation | Elements and methods for coalescing a discontinuous phase of a fluid from a continuous phase |
US5814118A (en) * | 1996-11-18 | 1998-09-29 | Nuclear Filter Technology, Inc. | HEPA filter for venting chambers |
WO2005049177A1 (fr) * | 2003-11-17 | 2005-06-02 | Donaldson Company, Inc. | Dispositif separateur permettant de separer les gaz et les liquides et procedes correspondants |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102172509B (zh) * | 2011-01-25 | 2013-09-18 | 太原理工大学 | 一种细粒煤的超声电解脱水方法 |
CN102172509A (zh) * | 2011-01-25 | 2011-09-07 | 太原理工大学 | 一种细粒煤的超声电解脱水方法 |
US9144760B2 (en) | 2012-07-03 | 2015-09-29 | The University Of Akron | Liquid drainage from coalescing filter medium with drainage channels |
EP2918939A1 (fr) * | 2014-03-14 | 2015-09-16 | BERNER INTERNATIONAL GmbH | Cartouche filtrante pour une hotte de sécurité et hotte de sécurité dotée d'au moins une cartouche filtrante |
US10018086B2 (en) | 2014-09-15 | 2018-07-10 | Ge Jenbacher Gmbh & Co Og | Filter |
AT14696U1 (de) * | 2014-09-15 | 2016-04-15 | Ge Jenbacher Gmbh & Co Og | Filter |
CN104383755A (zh) * | 2014-10-08 | 2015-03-04 | 何茂林 | 一种油气过滤滤芯及油气分离方法 |
WO2017093441A1 (fr) * | 2015-12-01 | 2017-06-08 | Ateliers Busch Sa | Pompe a vide avec element filtrant |
WO2017092795A1 (fr) * | 2015-12-01 | 2017-06-08 | Ateliers Busch S.A. | Pompe a vide avec element filtrant |
EP3663585A1 (fr) * | 2015-12-01 | 2020-06-10 | Ateliers Busch S.A. | Pompe à vide avec element filtrant |
RU2730191C2 (ru) * | 2015-12-01 | 2020-08-19 | Ателье Буш Са | Вакуумный насос и патрон для вакуумного насоса |
AU2016363589B2 (en) * | 2015-12-01 | 2020-12-10 | Ateliers Busch Sa | Vacuum pump with filtering element |
US11319958B2 (en) | 2015-12-01 | 2022-05-03 | Ateliers Busch Sa | Filtering element and associated mounting device for vacuum pump |
CN108712926A (zh) * | 2016-03-01 | 2018-10-26 | Smc株式会社 | 过滤器元件 |
CN108712926B (zh) * | 2016-03-01 | 2021-04-30 | Smc株式会社 | 过滤器元件 |
WO2024003544A1 (fr) | 2022-06-29 | 2024-01-04 | Psi Global Ltd | Silencieux de filtre |
Also Published As
Publication number | Publication date |
---|---|
GB0710151D0 (en) | 2007-07-04 |
GB2449846A (en) | 2008-12-10 |
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