WO1995030120A1 - Perforated plate filter media and related products - Google Patents
Perforated plate filter media and related products Download PDFInfo
- Publication number
- WO1995030120A1 WO1995030120A1 PCT/US1994/004777 US9404777W WO9530120A1 WO 1995030120 A1 WO1995030120 A1 WO 1995030120A1 US 9404777 W US9404777 W US 9404777W WO 9530120 A1 WO9530120 A1 WO 9530120A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- plate
- holes
- plates
- perforated
- filter
- Prior art date
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 29
- 239000012530 fluid Substances 0.000 claims abstract description 23
- 238000001125 extrusion Methods 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 9
- 239000000356 contaminant Substances 0.000 claims abstract description 8
- 230000008569 process Effects 0.000 claims abstract description 6
- 238000005530 etching Methods 0.000 claims abstract 2
- 239000002245 particle Substances 0.000 claims description 18
- 239000007788 liquid Substances 0.000 claims description 13
- 239000011159 matrix material Substances 0.000 claims description 6
- 239000011347 resin Substances 0.000 claims description 6
- 229920005989 resin Polymers 0.000 claims description 6
- 230000009969 flowable effect Effects 0.000 claims description 2
- 229920003002 synthetic resin Polymers 0.000 claims description 2
- 239000000057 synthetic resin Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 14
- 238000000926 separation method Methods 0.000 abstract description 8
- 238000002347 injection Methods 0.000 abstract description 6
- 239000007924 injection Substances 0.000 abstract description 6
- 238000009826 distribution Methods 0.000 abstract description 4
- 238000005491 wire drawing Methods 0.000 abstract description 2
- 239000002131 composite material Substances 0.000 abstract 1
- 239000011148 porous material Substances 0.000 description 24
- 238000001914 filtration Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000007787 solid Substances 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 7
- 239000010949 copper Substances 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 241000894006 Bacteria Species 0.000 description 3
- RJSRQTFBFAJJIL-UHFFFAOYSA-N niobium titanium Chemical compound [Ti].[Nb] RJSRQTFBFAJJIL-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 229910001275 Niobium-titanium Inorganic materials 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000005549 size reduction Methods 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 108091081062 Repeated sequence (DNA) Proteins 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000012620 biological material Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000011118 depth filtration Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005323 electroforming Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000010720 hydraulic oil Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000005555 metalworking Methods 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000011345 viscous material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/231—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids by bubbling
- B01F23/23105—Arrangement or manipulation of the gas bubbling devices
- B01F23/2312—Diffusers
- B01F23/23123—Diffusers consisting of rigid porous or perforated 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
- B01D29/03—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 self-supporting
-
- 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
- B01D29/39—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 hollow discs side by side on, or around, one or more tubes, e.g. of the leaf type
- B01D29/41—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 hollow discs side by side on, or around, one or more tubes, e.g. of the leaf type mounted transversely on the tube
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
- B01D39/1692—Other shaped material, e.g. perforated or porous sheets
-
- 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
- B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
- B01D46/12—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces in multiple arrangements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/231—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids by bubbling
- B01F23/23105—Arrangement or manipulation of the gas bubbling devices
- B01F23/2311—Mounting the bubbling devices or the diffusers
- B01F23/23113—Mounting the bubbling devices or the diffusers characterised by the disposition of the bubbling elements in particular configurations, patterns or arrays
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/231—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids by bubbling
- B01F23/23105—Arrangement or manipulation of the gas bubbling devices
- B01F23/2312—Diffusers
- B01F23/23126—Diffusers characterised by the shape of the diffuser element
- B01F23/231264—Diffusers characterised by the shape of the diffuser element being in the form of plates, flat beams, flat membranes or films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/237—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media
- B01F23/2373—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids characterised by the physical or chemical properties of gases or vapours introduced in the liquid media for obtaining fine bubbles, i.e. bubbles with a size below 100 µm
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
- B01F25/21—Jet mixers, i.e. mixers using high-speed fluid streams with submerged injectors, e.g. nozzles, for injecting high-pressure jets into a large volume or into mixing chambers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/18—Filters characterised by the openings or pores
- B01D2201/184—Special form, dimension of the openings, pores of the filtering elements
Definitions
- This invention relates generally to filters, separation equipment, and injector elements.
- Perforated metal plates are useful as filter media for mechanical filters. Filters of this type operate on the basis that the filter medium works as a simple porous barrier screen, removing and retaining solid particles too large to pass through the medium, but allowing the fluid in which the particles are suspended and particles smaller than the pores to pass through. These filters in effect provide direct interception of solids, with only a minor involvement of phenomena such as depth filtration which are major contributing mechanisms in other types of filtration. The intercepted particles are stopped at the upstream surface of the perforated plate, their size preventing them from passing through the pores. Surface retention of the particles provides an advantage in that the particles may be readily removed, allowing for re-use of the plate medium. Perforated metal plates also offer potential advantages in their strength and resistance to corrosion and capability for service in high-temperature fluids or in high-pressure applications as compared with other types of filter media.
- perforated plate filter media While potentially favorable aspects of perforated plate filter media are well-known, practical limitations have been imposed on their use owing to the difficulty of fabricating them with desired perforation sizes. As stated in Solid/Liquid Separation Technology by Arthur B. Purchas, published by Uplands Press Ltd. (1981), at pages 116-117: The use of perforated metal sheets as filter media is generally of very restricted interest since standard metal working techniques are unable to produce holes of sufficient fineness and regularity, excepting for applications such as in roughing strainers ; for example, the finest grade in the very extensive range of Greenings has holes of 0.26 in . (i .e . , 660 microns) , the porosity of this being 22 .6% .
- Expanded metal sheets have diamond-shaped apertures even the smallest of which in the so-called Micromesh range typically is 0. 75 mm X
- the most useful range of perforated metal sheets are those made by electro forming techniques combined with photoetching .
- This is the basis of the two ranges of nickel products available from Veco, the one being sheets with a maximum size of 200 X 200 mm, with holes as small as 5 microns (tolerance being ⁇ 2 microns on holes up to 500 microns) ; such small holes result in very low porosities, down to less than 2% .
- the second range comprises sheets of 1 m X 1 m; the finest grade has 0 .04 mm (40 microns) holes, with a porosity of 3 .5%, other hole sizes and porosities being 60 microns (8%) , 80 microns (14 .5%) , 100 microns (22 .5%) , all of these being at a pitch of 0 .20 mm with a key thickness of between 0.04 and 0.07 mm .
- pitch and shape of hole result in a wide variety of grades with holes up to 5 mm .
- SUBSTITUTESHEET(RULE26j plates unsuitable for many important filtration applications.
- pollutants such as various types of dust, liquid mist particles, bacteria, pollens, spores, and other biological materials are smaller in most cases than the available pore sizes so that such materials would pass through such a medium unaffected.
- pore sizes down to less than one micron in diameter are needed.
- filter media at the smaller sizes have pore sizes extending over a considerable range of values, rather than a single precise value.
- the ability to selectively remove particles of specific size would be enhanced by providing plates with a controlled, uniform pore diameter. Maximum uniformity of pore shape as well as size is needed to provide for separation of materials within precise, narrowly defined size ranges.
- Another important feature needed for perforated plate filter media is a high degree of strength and durability such as to allow the plate to be subjected to removal of particles and to be reused, after undergoing sterilization, chemical cleaning, or the like. Requirements also exist for perforated plates with properties similar to those discussed above for applications involving an injection or extrusion step. Very small and uniform size pores, consistent with strength and durability, are important for such purposes. Summary of the Invention
- the present invention is directed to perforated metal plates for use in filters and other separation and injection and extrusion equipment.
- Plates with uniformly sized and shaped pores at a selected size down to well below one micron and having a uniform cross section throughout the thickness of the plate are obtained by means of a compound "wire drawing" process wherein a sacrificial wire material is disposed lengthwise in an extrusion can and is surrounded by a desired plate material to form a billet.
- the billet is initially extruded and then restacked and drawn repeatedly, with the wire material being thinned out by each cycle.
- the wire-containing billet is cut into plates, and the wire is selectively etched away, leaving perforated plates.
- the perforated plates of this invention exhibit numerous other desirable features and advantages.
- a selected total porosity up to fifty percent of the plate area, and even higher in the case of certain non-circular holes, may be provided, thus enabling a high fluid flow through the plate and allowing use of such plates as filter media in pressurized or high pressure systems.
- the plates may be made at any desired thickness by selecting the location of cuts across the billet in making the plates. This provides for relatively thick plates, for example, up to one-fourth inch thick, with high strength and durability and ruggedness enough to withstand high pressure and repeated cycles of cleaning when used as a filter medium.
- the holes in such plates exhibit a high length-to-diameter ratio, which is important for some applications.
- Distribution of pores and hole dimensions may be varied at different locations across the plate, for example, some regions may be given small holes, some larger holes, and some no holes at all, all in the same plates.
- Single plates may be used as a flat disc or strainer or filter medium mounted in a housing, with a fluid passing perpendicularly through the plate.
- Multiple plates may be placed between spacers in a stacked array, with the plates having the same hole size, or in a graded configuration adapted for removal of coarse particles by a first plate having a larger pore size and progressively finer particles by succeeding plates with smaller hole sizes.
- Multiple plates may also be mounted in a supporting structure to form a large single filtration surface of a selected geometry including, but not limited to flat, cylindrical, domed (parabolic or spherical) , fan-fold, or pleated.
- the plates may also be placed in a rotary drum or disc filter provided with a scraper for removal of deposited particles.
- the plates may be made of a wide variety of metal or alloys that are amenable to being extruded or drawn as required in the fabrication process. This allows for selection of a particular material for compatibility with a specific environment in terms of chemical, thermal, and mechanical requirements.
- the plates can be made of copper, niobium, stainless steel, nickel, nickel- based alloys, and silver. In each case, the plate metal is co-extruded with a "wire" metal that is selectively removable with an etchant in the manufacturing process.
- perforated plates with uniform holes of a selected size in the lower micron range allows separation of many biological contaminants such as most bacteria, pollen, spores, and the like as well as inorganic dust and chemical contaminants.
- filter media of the present invention may be used a first stage in combination with a subsequent stage using a medium having a smaller pore size, for example, a membrane filter.
- Perforated plates embodying the invention are also useful for other applications wherein a first fluid is forced through small openings for injection or distribution into a second fluid or a solid or a viscous material is extruded through multiple openings.
- Another object is to provide such a perforated metallic plate filter medium having pores of uniform geometry throughout the thickness of the plate.
- Yet another object is to provide a perforated metal plate filter medium having uniform size holes of a selected diameter such as to enable precise separation from fluids of particles having a specified size.
- Still another object is to provide a perforated metal plate having a multiplicity of uniform-sized pores of a diameter such as to remove most bacteria and other biological contaminants from fluids passing through the plate.
- Another object is to provide perforated plates having a high degree of porosity, consistent with strength and durability.
- a further object is to provide perforated metal plates suitable for injection of one fluid into another fluid.
- Another object is to provide perforated metal plates for use in spinnerets through which synthetic fibers are extruded.
- Fig. 1 is a top plan view of a perforated plate filter medium embodying the invention.
- Fig. 2 is a fragmentary sectional view taken along a portion of line 2-2 of Fig. 1.
- Fig. 3 is a view, partly in section, of a filter for removing contaminants from a hydraulic liquid line.
- Fig. 4 is a pictorial view, partly broken away, of an air filter including an array of perforated plates.
- Fig. 5 is an elevational view, partly in section, of a "leaf” filter embodying the invention.
- Fig. 6 is an elevational view, partly in section, of a perforated plate fluid injector.
- Fig. 7 is an elevational view, partly in section, of a perforated plate extrusion element for a spinneret.
- Fig. 8 is a schematic view of a process for preparing perforated plates for use in the invention.
- a perforated metal plate 10 embodying the invention.
- the plate has a metal matrix 12 penetrated by a multiplicity of circular holes 14 spaced throughout the plate in hexagonal groups 16. (The diameter of the holes is enlarged in this view, exaggerated for the purposes of clarity.)
- the groups of holes are separated from one another by solid regions 18 in a pattern that results from the manner of stacking of hexagonal rods in the manufacturing process.
- An outer rim 19 extends around the circumference of the plate. The presence of solid regions between groups of holes and the solid outer rim are not critical and may be avoided by varying the manufacturing process.
- the holes have highly uniform dimensions and spacing throughout the plate and have a uniform cross section across the plate as shown in Fig. 2.
- FIG. 8 These characteristics result from the fabrication process as illustrated in Fig. 8 wherein the individual wires, which are later etched away to form holes, are each extruded under identical conditions.
- the holes shown in Fig. 1 have a round cross section by virtue of using a round billet in the first step of the preparation process.
- Other shapes such as square, hexagonal, or star-shaped may be obtained by using a billet with a corresponding cross- sectional shape, which is maintained throughout subsequent re-extrusion steps.
- the holes in the plate may have a diameter down to approximately 0.5 micron.
- An exact lower limit has not yet been established, but practical considerations would likely prevent making holes with smaller diameters; sizes down to 0.8 micron have actually been demonstrated.
- the invention loses its advantages over previously known perforated plates made by methods such as stamping or drilling.
- An optimum size of a particular filtering application would be selected, depending on the size of the particles to be filtered from a fluid.
- Porosity of the plate may be controlled in the preparation process to obtain a selected value of up to 50 percent for circular holes and up to 70 percent for hexagonal or square holes.
- a porosity of 30 to 60 percent is preferred in order to obtain a minimum reduction in flow across the plate, consistent with strength and durability.
- Thickness of the plate may also be varied as required for a particular application. For use in pressurized systems or under conditions where the plate is exposed to substantial stress, a thickness of 1/32 to 1/4 inch is preferred. This feature is readily controlled by cutting the finished rod into a wafer of a desired thickness in the preparation process.
- Fig. 3 shows an illustrative embodiment wherein a perforated plate filter medium 20 is used in a filter 22 disposed across a hydraulic line 24.
- the filter has a housing 26, an input 28 through which hydraulic oil is pumped by means not shown, and an outlet 30 through which the filtered oil is withdrawn.
- the hole size may be selected to provide appropriate filtration for a specific system. In general, a hole size in the range of 1 to 40 microns is used in accordance with the following recommended filter ratings as given in Filters and Filtration Handbook, Gulf Publishing Company (1981) , page 362:
- the specific hole size may thus be selected, depending on system requirement.
- a porosity of 30 to 60 percent and a plate thickness of 1/32 to 1/4 inch are preferred for filters for such systems, with thicker plates being used for high-pressure applications.
- Fig. 4 shows an embodiment wherein an air filter 32 with multiple perforated plate elements 34 mounted in a supporting substrate 36 is secured to housing 38.
- the filter has an inlet pipe 41 communicating with an air duct (not shown) and an outlet pipe 43 for egress of filtered air.
- Hole size, porosity, and plate thickness for this embodiment may be selected depending on filtration requirements for a specific system. In general, a minimum hole size, maximum porosity, and a thickness such as to provide high strength are preferred for this application, and specific values of 0.5 to 20 microns hole size, 30 to 60 percent porosity, and 1/64 to 1/8 inch thickness are suitable for this purpose.
- the mounting of the individual plate elements to the substrate as well as mounting of the substrate to the housing may be accomplished by conventional welding.
- filters with a single perforated plate element may be used for this application, multiple elements are preferred inasmuch as flow requirements for bulk air filters would normally be relatively high so that a large plate area would be needed.
- the plate area available in a single plate is limited by the size of extrusion equipment used in making the plates. Thus, separate, smaller plates are combined into a larger array to provide the desired area.
- a leaf filter 40 employing a stacked array of vertically spaced-apart circular perforated plates 42 is shown in Fig. 5.
- This filter has a vertically disposed cylindrical housing 44 and an open annular space 46 around the circumference of the plates 42.
- a liquid being filtered is introduced under pressure at an axially located inlet 48 at the top and is forced to pass through the plates while moving inwardly from the annular space 46 to axial space 50 leading to exit 52.
- This filter is useful for removing solid particulates from liquids.
- a perforation size of 1 to 200 microns is preferred, along with a porosity of 30 to 60 percent and a plate thickness of 1/64 to 1/8 inch.
- Fig. 6 shows a fluid injector 54 by means of which a gas is introduced into and dispersed within a liquid container 56.
- the injector has a cylindrical housing 58 with a gas inlet 60 at the top by means of which a pressurized gas is introduced from a source not shown.
- Perforated plate 62 having a multiplicity of extremely small holes 64 is disposed across the bottom end of the container, dispersing the gas into small bubbles 66 as it passes through.
- Injectors of this construction may be used for aeration and purification of water and in similar applications where dispersal of gas to form very small gas bubbles within a liquid is desired.
- Perforated plate injectors may also be used for injecting and atomizing or finely dispersing liquids into defined locations, for example, for injecting diesel fuel or gasoline into a cavity within an engine.
- a perforation size of 10 to 300 microns, a total porosity of 30 to 60 percent, and a plate thickness of 1/64 to 1/16 inch are preferred.
- Fig. 7 shows a spinneret 68 for extrusion of synthetic resin material in the manufacture of resin filaments for yarn or the like.
- the spinneret has a housing 70 into which flowable, heated resin 72 is forced by means not shown.
- a perforated plate 74 with very small holes 76 extends across the bottom of the housing.
- the resin is formed into fine filaments 78 which solidify upon cooling after passage through the plate.
- Spinnerets embodying the invention are useful for making resin filaments with a very small and uniform diameter.
- a special advantage is provided in that a precisely defined hole diameter may be obtained in these plates.
- a hole size of 1 to 300 microns, a porosity of 10 to 60 percent, and a plate thickness of 1/64 to 1/16 inch are preferred.
- Fig. 8 Preparation of perforated plates embodying the invention is schematically illustrated in Fig. 8.
- the plate material in this embodiment is copper, and the sacrificial wire material is a niobium-titanium alloy.
- a generally cylindrical extrusion can, conical at one end, is made up of copper, and a cylindrical billet of sacrificial niobium-titanium alloy is placed inside the can.
- a lid of copper is then fitted over the flat end of the can, and the assembly is evacuated and sealed by welding.
- the sealed can is preheated to a temperature of at least 400°C and extruded through a die to obtain an elongation of fifty percent or more.
- An extruded cylindrical rod made up of niobium-titanium core surrounded by copper is produced in this step. Subsequent size reductions are then carried out by extrusion steps in which the rod is pushed through a die or by drawing in which the rod is pulled, but drawing is preferred after the initial size reduction.
- the rods are then converted to hexagonal shape as shown by drawing through a hexagonal die or machining as required.
- the hexagonal single core rods are then stacked within a cylindrical copper can, and the can is provided with a lid and is subjected to preheating and re-extrusion in the same manner as for the starting billet.
Abstract
Perforated plates (10) for use as filter media and devices for fluid injection and extrusion have a multiplicity of holes (14) of a uniform size and a selected diameter as small as 0.5 micron. The plates are made by a 'wire drawing' process wherein a sacrificial wire material in plate metal can is repeatedly extruded and restacked, elongating the wire and reducing its diameter. Plates are then cut from the extruded composite, and the wire metal is removed by selective etching (Fig. 8). By use of this process, perforated plates with several features unavailable previously are obtained. In particular, the plates have much smaller holes, higher porosity, and uniform size and shape, along with any desired thickness and a high length-to-diameter ratio. Such plates are ideally suited for use as a medium for various types of filters where removal of contaminants sized in the lower micron range is desired. Size and distribution of the holes in the plate are precisely controllable, enabling separations of materials of specific sizes.
Description
PERFORATED PLATE FILTER MEDIA AND RELATED PRODUCTS
Reference to Related Applications
This application is a continuation-in-part of application Serial No. 07/800,220, filed November 27, 1991, which in turn is a continuation-in-part of application Serial No. 07/530,873, filed May 29, 1990, which in turn is a continuation-in-part of application Serial No. 07/375,709, filed July 5, 1989, now U.S. Patent No. 5,101,894, issued April 7, 1992.
Field of the Invention
This invention relates generally to filters, separation equipment, and injector elements.
Background of the Invention
Perforated metal plates are useful as filter media for mechanical filters. Filters of this type operate on the basis that the filter medium works as a simple porous barrier screen, removing and retaining solid particles too large to pass through the medium, but allowing the fluid in which the particles are suspended and particles smaller than the pores to pass through. These filters in effect provide direct interception of solids, with only a minor involvement of phenomena such as depth filtration which are major contributing mechanisms in other types of filtration. The intercepted particles are stopped at the upstream surface of the perforated plate, their size preventing them from passing through the pores. Surface retention of the particles provides an advantage in that the particles may be readily removed, allowing for re-use of the plate medium. Perforated metal plates also offer potential advantages in their strength and resistance to corrosion and capability for service in high-temperature fluids or in high-pressure applications as compared with other types of filter media.
While potentially favorable aspects of perforated plate filter media are well-known, practical limitations have been imposed on their use owing to the difficulty of
fabricating them with desired perforation sizes. As stated in Solid/Liquid Separation Technology by Derek B. Purchas, published by Uplands Press Ltd. (1981), at pages 116-117: The use of perforated metal sheets as filter media is generally of very restricted interest since standard metal working techniques are unable to produce holes of sufficient fineness and regularity, excepting for applications such as in roughing strainers ; for example, the finest grade in the very extensive range of Greenings has holes of 0.26 in . (i .e . , 660 microns) , the porosity of this being 22 .6% .
Expanded metal sheets have diamond-shaped apertures even the smallest of which in the so- called Micromesh range typically is 0. 75 mm X
0.60 mm (along its long and short axes, respectively) .
From the filtration point of view, the most useful range of perforated metal sheets are those made by electro forming techniques combined with photoetching . This is the basis of the two ranges of nickel products available from Veco, the one being sheets with a maximum size of 200 X 200 mm, with holes as small as 5 microns (tolerance being ± 2 microns on holes up to 500 microns) ; such small holes result in very low porosities, down to less than 2% .
The second range comprises sheets of 1 m X 1 m; the finest grade has 0 .04 mm (40 microns) holes, with a porosity of 3 .5%, other hole sizes and porosities being 60 microns (8%) , 80 microns (14 .5%) , 100 microns (22 .5%) , all of these being at a pitch of 0 .20 mm with a key thickness of between 0.04 and 0.07 mm . In practice, there are numerous variations of factors such as pitch and shape of hole, result in a wide variety of grades with holes up to 5 mm .
These limitations of perforated plates to large pore sizes and low porosities have served to render perforated
SUBSTITUTESHEET(RULE26j
plates unsuitable for many important filtration applications. In terms of pore size, pollutants such as various types of dust, liquid mist particles, bacteria, pollens, spores, and other biological materials are smaller in most cases than the available pore sizes so that such materials would pass through such a medium unaffected. In particular, pore sizes down to less than one micron in diameter are needed.
In addition to smaller pore sizes, a higher total porosity is needed for applications requiring a high throughput or involving exposure to pressurized fluids. As stated above, prior perforated metal sheets with pore sizes as small as five microns provide a porosity of less than two percent. A much higher porosity is required for practical applications. Uniformity of pore size and of distribution have also been lacking in prior plates at the smaller sizes. Filter media are rated on their ability to remove particles of a specific size from a fluid. Ideally, the medium would have a precise cut-off point, which refers to the largest particle, normally expressed in microns, which would pass through the filter. In practice, filter media at the smaller sizes have pore sizes extending over a considerable range of values, rather than a single precise value. The ability to selectively remove particles of specific size would be enhanced by providing plates with a controlled, uniform pore diameter. Maximum uniformity of pore shape as well as size is needed to provide for separation of materials within precise, narrowly defined size ranges. Another important feature needed for perforated plate filter media is a high degree of strength and durability such as to allow the plate to be subjected to removal of particles and to be reused, after undergoing sterilization, chemical cleaning, or the like. Requirements also exist for perforated plates with properties similar to those discussed above for applications involving an injection or extrusion step. Very small and uniform size pores, consistent with strength and durability, are important for such purposes.
Summary of the Invention
The present invention is directed to perforated metal plates for use in filters and other separation and injection and extrusion equipment. Plates with uniformly sized and shaped pores at a selected size down to well below one micron and having a uniform cross section throughout the thickness of the plate are obtained by means of a compound "wire drawing" process wherein a sacrificial wire material is disposed lengthwise in an extrusion can and is surrounded by a desired plate material to form a billet. The billet is initially extruded and then restacked and drawn repeatedly, with the wire material being thinned out by each cycle. When the desired wire diameter is reached, the wire-containing billet is cut into plates, and the wire is selectively etched away, leaving perforated plates.
In addition to providing uniform-sized pores having a diameter much smaller than available previously, the perforated plates of this invention exhibit numerous other desirable features and advantages. A selected total porosity up to fifty percent of the plate area, and even higher in the case of certain non-circular holes, may be provided, thus enabling a high fluid flow through the plate and allowing use of such plates as filter media in pressurized or high pressure systems. The plates may be made at any desired thickness by selecting the location of cuts across the billet in making the plates. This provides for relatively thick plates, for example, up to one-fourth inch thick, with high strength and durability and ruggedness enough to withstand high pressure and repeated cycles of cleaning when used as a filter medium. The holes in such plates exhibit a high length-to-diameter ratio, which is important for some applications.
Distribution of pores and hole dimensions may be varied at different locations across the plate, for example, some regions may be given small holes, some larger holes, and some no holes at all, all in the same plates.
Another important feature of plates embodying the invention is that the high degree of uniformity of pore
size provides a sharp, well-defined cut-off point, thus enabling precise separation of different size materials from a mixture in a fluid. This is in contrast to prior porous material such as sintered metals and ceramics which, in the smaller sizes of interest, lack uniformity and which require consideration in terms of an average pore size, with actual sizes varying over a substantial range.
Plate characteristics made available by the invention open the way for a wide variety of filtration applications. Single plates may be used as a flat disc or strainer or filter medium mounted in a housing, with a fluid passing perpendicularly through the plate. Multiple plates may be placed between spacers in a stacked array, with the plates having the same hole size, or in a graded configuration adapted for removal of coarse particles by a first plate having a larger pore size and progressively finer particles by succeeding plates with smaller hole sizes. Multiple plates may also be mounted in a supporting structure to form a large single filtration surface of a selected geometry including, but not limited to flat, cylindrical, domed (parabolic or spherical) , fan-fold, or pleated. The plates may also be placed in a rotary drum or disc filter provided with a scraper for removal of deposited particles.
The plates may be made of a wide variety of metal or alloys that are amenable to being extruded or drawn as required in the fabrication process. This allows for selection of a particular material for compatibility with a specific environment in terms of chemical, thermal, and mechanical requirements. In particular, the plates can be made of copper, niobium, stainless steel, nickel, nickel- based alloys, and silver. In each case, the plate metal is co-extruded with a "wire" metal that is selectively removable with an etchant in the manufacturing process.
The availability of perforated plates with uniform holes of a selected size in the lower micron range allows separation of many biological contaminants such as most bacteria, pollen, spores, and the like as well as inorganic dust and chemical contaminants. For filtration of fluids such as air or water containing particles of these sizes
along with even smaller particles, filter media of the present invention may be used a first stage in combination with a subsequent stage using a medium having a smaller pore size, for example, a membrane filter. Perforated plates embodying the invention are also useful for other applications wherein a first fluid is forced through small openings for injection or distribution into a second fluid or a solid or a viscous material is extruded through multiple openings. These applications may take the form of aeration and water purification devices wherein a gas is dispensed into a liquid as tiny bubbles, in fuel injectors, and in spinnerets through which synthetic materials are extruded in the manufacture of fibers. It is, therefore, an object of this invention to provide a perforated metal plate filter medium having a multiplicity of uniform-size pores with a selected diameter down to the lower micron size range.
Another object is to provide such a perforated metallic plate filter medium having pores of uniform geometry throughout the thickness of the plate.
Yet another object is to provide a perforated metal plate filter medium having uniform size holes of a selected diameter such as to enable precise separation from fluids of particles having a specified size.
Still another object is to provide a perforated metal plate having a multiplicity of uniform-sized pores of a diameter such as to remove most bacteria and other biological contaminants from fluids passing through the plate.
Another object is to provide perforated plates having a high degree of porosity, consistent with strength and durability.
A further object is to provide perforated metal plates suitable for injection of one fluid into another fluid.
Another object is to provide perforated metal plates for use in spinnerets through which synthetic fibers are extruded.
Other objects and advantages of the invention will be
apparent from the following detailed description and the appended claims.
Brief Description of the Drawings
Fig. 1 is a top plan view of a perforated plate filter medium embodying the invention.
Fig. 2 is a fragmentary sectional view taken along a portion of line 2-2 of Fig. 1.
Fig. 3 is a view, partly in section, of a filter for removing contaminants from a hydraulic liquid line. Fig. 4 is a pictorial view, partly broken away, of an air filter including an array of perforated plates.
Fig. 5 is an elevational view, partly in section, of a "leaf" filter embodying the invention.
Fig. 6 is an elevational view, partly in section, of a perforated plate fluid injector.
Fig. 7 is an elevational view, partly in section, of a perforated plate extrusion element for a spinneret.
Fig. 8 is a schematic view of a process for preparing perforated plates for use in the invention.
Description of the Preferred Embodiment
Referring to Fig. 1 of the drawings, there is shown a perforated metal plate 10 embodying the invention. The plate has a metal matrix 12 penetrated by a multiplicity of circular holes 14 spaced throughout the plate in hexagonal groups 16. (The diameter of the holes is enlarged in this view, exaggerated for the purposes of clarity.) The groups of holes are separated from one another by solid regions 18 in a pattern that results from the manner of stacking of hexagonal rods in the manufacturing process. An outer rim 19 extends around the circumference of the plate. The presence of solid regions between groups of holes and the solid outer rim are not critical and may be avoided by varying the manufacturing process. The holes have highly uniform dimensions and spacing throughout the plate and have a uniform cross section across the plate as shown in Fig. 2. These characteristics result from the fabrication process as illustrated in Fig. 8 wherein the individual
wires, which are later etched away to form holes, are each extruded under identical conditions. The holes shown in Fig. 1 have a round cross section by virtue of using a round billet in the first step of the preparation process. Other shapes such as square, hexagonal, or star-shaped may be obtained by using a billet with a corresponding cross- sectional shape, which is maintained throughout subsequent re-extrusion steps.
The holes in the plate may have a diameter down to approximately 0.5 micron. An exact lower limit has not yet been established, but practical considerations would likely prevent making holes with smaller diameters; sizes down to 0.8 micron have actually been demonstrated. At hole sizes above about 1/16 inch (1,600 microns), the invention loses its advantages over previously known perforated plates made by methods such as stamping or drilling. An optimum size of a particular filtering application would be selected, depending on the size of the particles to be filtered from a fluid. Porosity of the plate may be controlled in the preparation process to obtain a selected value of up to 50 percent for circular holes and up to 70 percent for hexagonal or square holes. For most applications, a porosity of 30 to 60 percent is preferred in order to obtain a minimum reduction in flow across the plate, consistent with strength and durability. Thickness of the plate may also be varied as required for a particular application. For use in pressurized systems or under conditions where the plate is exposed to substantial stress, a thickness of 1/32 to 1/4 inch is preferred. This feature is readily controlled by cutting the finished rod into a wafer of a desired thickness in the preparation process.
Fig. 3 shows an illustrative embodiment wherein a perforated plate filter medium 20 is used in a filter 22 disposed across a hydraulic line 24. The filter has a housing 26, an input 28 through which hydraulic oil is pumped by means not shown, and an outlet 30 through which the filtered oil is withdrawn. The hole size may be
selected to provide appropriate filtration for a specific system. In general, a hole size in the range of 1 to 40 microns is used in accordance with the following recommended filter ratings as given in Filters and Filtration Handbook, Gulf Publishing Company (1981) , page 362:
Accepting 25 μm as a general level of protection required for low pressure industrial hydraulic systems, and in the absence of specific requirements from the component manufacturers, the followmg filter ratings are recommended for different systems
filler rating Low pressure systems with generous clearances 25-<t0 μm
Low pressure heavy-duty systems 15-25 μm
Typical medium pressure industrial systems 12-15 μm
Mobile hydraulic systems 12-15 μm
General machine tool and other high quality systems 10-12 μm High performance machine tool and other high pressure systems where reliability is critical 3-5 μm
Critical high pressure systems and controls using miniature components l- μ
The specific hole size may thus be selected, depending on system requirement. A porosity of 30 to 60 percent and a plate thickness of 1/32 to 1/4 inch are preferred for filters for such systems, with thicker plates being used for high-pressure applications.
Fig. 4 shows an embodiment wherein an air filter 32 with multiple perforated plate elements 34 mounted in a supporting substrate 36 is secured to housing 38. The filter has an inlet pipe 41 communicating with an air duct (not shown) and an outlet pipe 43 for egress of filtered air. Hole size, porosity, and plate thickness for this embodiment may be selected depending on filtration requirements for a specific system. In general, a minimum hole size, maximum porosity, and a thickness such as to provide high strength are preferred for this application, and specific values of 0.5 to 20 microns hole size, 30 to 60 percent porosity, and 1/64 to 1/8 inch thickness are suitable for this purpose. The mounting of the individual plate elements to the substrate as well as mounting of the substrate to the housing may be accomplished by conventional welding.
Although filters with a single perforated plate
element may be used for this application, multiple elements are preferred inasmuch as flow requirements for bulk air filters would normally be relatively high so that a large plate area would be needed. As a practical matter, the plate area available in a single plate is limited by the size of extrusion equipment used in making the plates. Thus, separate, smaller plates are combined into a larger array to provide the desired area.
A leaf filter 40 employing a stacked array of vertically spaced-apart circular perforated plates 42 is shown in Fig. 5. This filter has a vertically disposed cylindrical housing 44 and an open annular space 46 around the circumference of the plates 42. A liquid being filtered is introduced under pressure at an axially located inlet 48 at the top and is forced to pass through the plates while moving inwardly from the annular space 46 to axial space 50 leading to exit 52. This filter is useful for removing solid particulates from liquids. For such applications, a perforation size of 1 to 200 microns is preferred, along with a porosity of 30 to 60 percent and a plate thickness of 1/64 to 1/8 inch.
Fig. 6 shows a fluid injector 54 by means of which a gas is introduced into and dispersed within a liquid container 56. The injector has a cylindrical housing 58 with a gas inlet 60 at the top by means of which a pressurized gas is introduced from a source not shown. Perforated plate 62 having a multiplicity of extremely small holes 64 is disposed across the bottom end of the container, dispersing the gas into small bubbles 66 as it passes through. Injectors of this construction may be used for aeration and purification of water and in similar applications where dispersal of gas to form very small gas bubbles within a liquid is desired. Perforated plate injectors may also be used for injecting and atomizing or finely dispersing liquids into defined locations, for example, for injecting diesel fuel or gasoline into a cavity within an engine. For liquid injection applications, a perforation size of 10 to 300 microns, a total porosity of 30 to 60 percent, and a plate thickness
of 1/64 to 1/16 inch are preferred.
Fig. 7 shows a spinneret 68 for extrusion of synthetic resin material in the manufacture of resin filaments for yarn or the like. The spinneret has a housing 70 into which flowable, heated resin 72 is forced by means not shown. A perforated plate 74 with very small holes 76 extends across the bottom of the housing. Upon passage through the plate, the resin is formed into fine filaments 78 which solidify upon cooling after passage through the plate. Spinnerets embodying the invention are useful for making resin filaments with a very small and uniform diameter. A special advantage is provided in that a precisely defined hole diameter may be obtained in these plates. A hole size of 1 to 300 microns, a porosity of 10 to 60 percent, and a plate thickness of 1/64 to 1/16 inch are preferred.
Preparation of perforated plates embodying the invention is schematically illustrated in Fig. 8. The plate material in this embodiment is copper, and the sacrificial wire material is a niobium-titanium alloy. A generally cylindrical extrusion can, conical at one end, is made up of copper, and a cylindrical billet of sacrificial niobium-titanium alloy is placed inside the can. A lid of copper is then fitted over the flat end of the can, and the assembly is evacuated and sealed by welding. The sealed can is preheated to a temperature of at least 400°C and extruded through a die to obtain an elongation of fifty percent or more. An extruded cylindrical rod made up of niobium-titanium core surrounded by copper is produced in this step. Subsequent size reductions are then carried out by extrusion steps in which the rod is pushed through a die or by drawing in which the rod is pulled, but drawing is preferred after the initial size reduction. In order to enable stacking of an array of single core rods, the rods are then converted to hexagonal shape as shown by drawing through a hexagonal die or machining as required. The hexagonal single core rods are then stacked within a cylindrical copper can, and the can is provided with a lid and is subjected to preheating and re-extrusion in the same
manner as for the starting billet. Repeated sequences of extrusion or drawing, conversion to hexagonal shape, and stacking are carried out until the billet material is thinned out to a desired diameter. At this point, the finished rod is cut into wafers, giving a desired plate thickness. The sacrificial material is etched away by hydrofluoric acid, leaving a matrix of copper with a multiplicity of small diameter holes having a uniform cross section throughout the plate thickness. It may be seen from the above that perforated metal plates embodying the invention lend themselves to many applications where the combined features of extremely small hole size, uniformity of hole size and geometry, and high porosity are important. In addition, the ruggedness and resistance of these plates to difficult environments provide for prolonged service in these applications.
While the invention is illustrated above with respect to various specific embodiments, it is not to be understood as limited thereto, but is limited only as indicated by the following claims.
Claims
1. A perforated plate comprising a metal matrix, a multiplicity of uniformly sized and shaped holes passing through said matrix and perpendicular thereto, said plates having been made by a process wherein a sacrificial wire metal is disposed lengthwise in an extrusion can surrounded by a desired matrix metal to form a billet and the billet is extruded or drawn, stacked, re-extruded or redrawn and restacked repeatedly to thin out the wire metal within the billet, the thinned-out billet is cut transversely to provide a desired plate thickness, and the resulting cut plate is selectively etched to remove the wire metal, leaving a perforated plate.
2. A perforated plate as defined in claim 1 wherein said holes have a diameter of 0.5 to 1,600 microns.
3. A perforated plate as defined in claim 2 wherein said plate has a total porosity of 30 to 70 percent.
4. A filter medium comprising a rigid metal plate perforated by a multiplicity of uniform-sized holes extending perpendicularly through the plate, said holes having a selected diameter in the range of 0.5 to 1,600 microns, and said holes having been formed by etching away of sacrificial wire metal in a repeatedly extruded or drawn matrix of plate metal. 5. A filter medium as defined in claim 4 wherein said holes have a diameter from 0.
5 to 40 microns.
6. A filter medium as defined in claim 5 wherein said plate has a porosity of 30 to 70 percent.
7. A filter medium as defined in claim 6 wherein said plate has a thickness of 1/32 to 1/4 inch.
8. A filter for removing contaminants from a liquid comprising: a housing having an inlet and an outlet and disposed across a line carrying said liquid; a perforated plate supported in said housing and arranged for flow of said liquid through said plate; and said plate having a multiplicity of uniform-sized holes of a selected diameter in the range of 0.5 to 40 microns.
9. A filter as defined in claim 8 wherein said plate has a total porosity of 30 to 60 percent.
10. An air filter for removing contaminants from an air stream comprising: a housing having an inlet and an outlet and disposed across a duct carrying said air stream; a perforated plate supported in said housing and arranged for flow from said air stream through said plate; and said plate having a multiplicity of uniform sized holes of a selected diameter in the range of 0.5 to 20 microns.
11. The air filter as defined in claim 10 wherein said plate has a porosity of 30 to 60 percent.
12. The air filter as defined in claim 11 including a support member disposed across said housing and a plurality of perforated plates secured to said support member.
13. The air filter as defined in claim 12 wherein said plates are located side by side in coplanar relation to one another.
14. An injector for introducing a first fluid in finely dispersed form into a second fluid comprising: a housing having a first end receiving a stream of said first fluid and a second end adapted to be placed within a volume of said second fluid; and a perforated plate disposed across said second end and penetrated by a multiplicity of holes of a selected diameter in the range of 10 to 300 microns.
15. The injector as defined in claim 14 wherein said perforated plate has a porosity of 10 to 60 percent.
16. The injector as defined in claim 15 wherein said plate has a thickness of 1/64 to 1/16 inch.
17. A spinneret for extrusion of flowable synthetic resin into filaments comprising: a housing adapted at one end to receive a quantity of said resin and having at an opposite end a perforated plate adapted to form said resin into filaments upon being forced therethrough; and said plate having a plurality of uniform-sized holes of a selected diameter in the range of 1 to 300 microns extending perpendicular to the plate.
18. The spinneret as defined in claim 17 wherein said perforated plate has a thickness of 1/64 to 1/16 inch.
19. A leaf filter comprising: a vertically disposed housing having a top inlet and a bottom outlet; a plurality of perforated plate discs arranged in vertically stacked, spaced-apart relation to one another, said discs having a central aperture defining an axial flow region and a circumferential region being defined between outer edges of said discs and said housing; and said plates being perforated by a multiplicity of holes of a selected uniform size in the range of 1 to 200 microns; whereby a fluid flowing from one of said regions to the other thereof will have contaminant particles removed therefrom.
20. The leaf filter as defined in claim 19 wherein said plate discs have a porosity of 30 to 60 percent.
21. The leaf filter as defined in claim 20 wherein said plate discs have a thickness of 1/64 to 1/8 inch.
SUBSTITUTESHEET(RULE26Ϊ
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1994/004777 WO1995030120A1 (en) | 1994-04-28 | 1994-04-28 | Perforated plate filter media and related products |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1994/004777 WO1995030120A1 (en) | 1994-04-28 | 1994-04-28 | Perforated plate filter media and related products |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995030120A1 true WO1995030120A1 (en) | 1995-11-09 |
Family
ID=22242517
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1994/004777 WO1995030120A1 (en) | 1994-04-28 | 1994-04-28 | Perforated plate filter media and related products |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO1995030120A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0963787A1 (en) * | 1996-02-20 | 1999-12-15 | JAPAN as represented by DIRECTOR GENERAL OF NATIONAL FOOD RESEARCH INSTITUTE, MINISTRY OF AGRICULTURE, FORESTRY AND FISHERIES | Method and device for producing emulsions |
CN110575764A (en) * | 2018-06-07 | 2019-12-17 | 埃尔微尘科技(北京)有限公司 | Heat and mass transfer device |
CN113877348A (en) * | 2021-11-01 | 2022-01-04 | 南京工业大学 | Cyclone separation and steel-ceramic composite flat membrane module high-temperature dust removal integrated device |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3692099A (en) * | 1968-06-20 | 1972-09-19 | Gen Electric | Ultra low temperature thermal regenerator |
US3852045A (en) * | 1972-08-14 | 1974-12-03 | Battelle Memorial Institute | Void metal composite material and method |
US4004615A (en) * | 1974-02-04 | 1977-01-25 | Klockner-Humboldt-Deutz Aktiengesellschaft | Parts subject to wear in separators, cyclones, pipelines and similar apparatus |
US4014968A (en) * | 1974-07-19 | 1977-03-29 | Corning Glass Works | Shrinkage control of cellular ceramic bodies having axial cavities |
US4118339A (en) * | 1976-11-01 | 1978-10-03 | Uop Inc. | Use of noble metal solutions in catalyst regeneration zones |
US4343604A (en) * | 1979-10-15 | 1982-08-10 | Ceraver | Die for extruding ceramic material to form a body of cellular structure, and a method of obtaining said die |
US4645700A (en) * | 1983-10-07 | 1987-02-24 | Ngk Insulators, Ltd. | Ceramic honeycomb structural body |
-
1994
- 1994-04-28 WO PCT/US1994/004777 patent/WO1995030120A1/en active Application Filing
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3692099A (en) * | 1968-06-20 | 1972-09-19 | Gen Electric | Ultra low temperature thermal regenerator |
US3852045A (en) * | 1972-08-14 | 1974-12-03 | Battelle Memorial Institute | Void metal composite material and method |
US4004615A (en) * | 1974-02-04 | 1977-01-25 | Klockner-Humboldt-Deutz Aktiengesellschaft | Parts subject to wear in separators, cyclones, pipelines and similar apparatus |
US4014968A (en) * | 1974-07-19 | 1977-03-29 | Corning Glass Works | Shrinkage control of cellular ceramic bodies having axial cavities |
US4118339A (en) * | 1976-11-01 | 1978-10-03 | Uop Inc. | Use of noble metal solutions in catalyst regeneration zones |
US4343604A (en) * | 1979-10-15 | 1982-08-10 | Ceraver | Die for extruding ceramic material to form a body of cellular structure, and a method of obtaining said die |
US4645700A (en) * | 1983-10-07 | 1987-02-24 | Ngk Insulators, Ltd. | Ceramic honeycomb structural body |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0963787A1 (en) * | 1996-02-20 | 1999-12-15 | JAPAN as represented by DIRECTOR GENERAL OF NATIONAL FOOD RESEARCH INSTITUTE, MINISTRY OF AGRICULTURE, FORESTRY AND FISHERIES | Method and device for producing emulsions |
EP0963787A4 (en) * | 1996-02-20 | 2002-01-23 | Jp Nat Food Res Inst Ministry | Method and device for producing emulsions |
CN110575764A (en) * | 2018-06-07 | 2019-12-17 | 埃尔微尘科技(北京)有限公司 | Heat and mass transfer device |
CN113877348A (en) * | 2021-11-01 | 2022-01-04 | 南京工业大学 | Cyclone separation and steel-ceramic composite flat membrane module high-temperature dust removal integrated device |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3064262B1 (en) | Filter medium, method for producing a filter medium and filter element with a filter medium | |
US3482703A (en) | Particulate and biological filters | |
EP3319704B1 (en) | Separation system for simultaneous removal of both solid particles and liquid droplets suspended in another liquid | |
US5510194A (en) | Perforated plate filter media and related products | |
US5873998A (en) | Inorganic tubular filter element including channels of non-circular section having optimized profile | |
US4793928A (en) | Polymer filtering apparatus | |
KR102471175B1 (en) | Tangential Flow Separator Elements with Flexible Channels | |
EP0780148A1 (en) | Filtration device or membrane device with increasing thickness walls | |
US6605215B2 (en) | Hybrid spin-on filter | |
GB1575049A (en) | Filter medium | |
US20070151920A1 (en) | System and method of micromolded filtration microstructure and devices | |
JP4422025B2 (en) | Filter plate | |
WO2000010685A1 (en) | Porous structures and methods and apparatus for forming porous structures | |
DE102010001504A1 (en) | Method for manufacturing e.g. microfilter unit, that is utilized for filtering e.g. medium in food product application, involves separating filter layers by etching processes such as wet-chemical or dry-chemical etching processes | |
JP2018516168A (en) | Monolithic column structure for separating fluid media | |
US5895572A (en) | Porous monolithic support for filtration membranes | |
US7445853B2 (en) | Layered filter structure comprising short metal fibers | |
WO1995030120A1 (en) | Perforated plate filter media and related products | |
DE2434828B2 (en) | DEVICE FOR FILTERING A LIQUID | |
JPH04215825A (en) | Manufacture of membrane for micro- filtration, ultra filtration, super evaporation, reverse osmosis, of suspension and emulsion or gas separation | |
CN1011482B (en) | Flat element for filtering and separation | |
JP2006088081A (en) | Method for filtering highly viscous fluid | |
JP3164151U (en) | Foreign matter removal filter | |
EP0455492A1 (en) | Filters for polymer spinneret assemblies and their manufacture | |
EP1663445B1 (en) | Filter for a spin pack assembly |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): JP |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
122 | Ep: pct application non-entry in european phase |