Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B5/00—Cleaning by methods involving the use of air flow or gas flow
  • B08B5/02—Cleaning by the force of jets, e.g. blowing-out cavities
  • B08B5/023—Cleaning travelling work
  • B08B5/026—Cleaning moving webs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
  • B05B1/005—Nozzles or other outlets specially adapted for discharging one or more gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H20/00—Advancing webs
  • B65H20/14—Advancing webs by direct action on web of moving fluid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/004—Nozzle assemblies; Air knives; Air distributors; Blow boxes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2301/00—Handling processes for sheets or webs
  • B65H2301/50—Auxiliary process performed during handling process
  • B65H2301/51—Modifying a characteristic of handled material
  • B65H2301/511—Processing surface of handled material upon transport or guiding thereof, e.g. cleaning
  • B65H2301/5115—Cleaning
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2301/00—Handling processes for sheets or webs
  • B65H2301/50—Auxiliary process performed during handling process
  • B65H2301/51—Modifying a characteristic of handled material
  • B65H2301/517—Drying material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2406/00—Means using fluid
  • B65H2406/10—Means using fluid made only for exhausting gaseous medium
  • B65H2406/12—Means using fluid made only for exhausting gaseous medium producing gas blast
  • B65H2406/122—Nozzles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2408/00—Specific machines
  • B65H2408/20—Specific machines for handling web(s)
  • B65H2408/21—Accumulators
  • B65H2408/217—Accumulators of rollers type, e.g. with at least one fixed and one movable roller

Definitions

• the present invention relates to apparatus for removal of liquid from a web and in particular, but not exclusively, for containment of a liquid within a process station and avoidance of it being carried by the web from the process station.
• I refer to such containment and avoidance of carrying as “isolation” by analogy with an isolating valve.
• I intend removal of bulk liquid and/or droplets of liquid, that is superficial dryness. I would not normally expect removal of bulk and droplet liquid to result in complete dryness. A substance may remain damp or wetted or carrying microscopic liquid despite being superficially dry. Accordingly references to "isolation" include superficial isolation and are not limited to isolation to the greatest extent possible as in a hospital isolation ward.
• Carry-over of chemicals can be obviated by use of web dryers between tanks.
• a transfer station can be bulky, and indeed involve risk of uneven drying. Uneven drying can result in uneven contact with plating liquid, for instance, and hence uneven plating.
• air knife in the present context, I mean:
• a pair of opposed members having opposed surfaces, each having a slit or a linear array of apertures through which air can be blown, for blowing a liquid from the opposite surfaces of a board, sheet or web ( "web" alone being used on occasion to include any of these) passing between the opposed members, in a passage direction.
• the slit or apertures will be angled to direct air flow oppositely to the direction of travel of the web, whereby the liquid will be blown back to towards the region where the web was treated with the liquid and whence the web is travelling, carrying residual liquid.
• the object of the present invention is to provide improved apparatus for liquid removal.
• liquid removal apparatus comprising an air knife with at least one elongate groove or rebate in at least one of the opposed surfaces of the pair of opposed members, the groove or rebate being up- or down-stream, in respect of the passage direction, of the respective slit or linear array of apertures.
• the air knife will have a length transversely of the passage direction longer than the web's width, but narrow in its passage direction compared with its length.
• each elongate groove or rebate will be at least substantially parallel to the respective slit or linear array of apertures.
• the or each opposed surface extends beyond the groove at least substantially flush with itself at the respective slit or linear array of apertures.
• the grooves will be provided as pairs, one in one opposed surface, the other in the other. Preferably such grooves will be aligned opposite each other, to keep a web between them centralised between the opposed surfaces.
• grooves can be staggered.
• the or each rebate extends outwards remotely from the respective slit or linear array of apertures to an edge of the rebated opposed member.
• the rebate may be of constant depth or of varying depth across its width.
• the width of the rebate can be greater than the extent of the opposed surface between the rebate and the slit or linear array of apertures.
• separation of the opposed surfaces is greater outwards of the or groove than inwards thereof, whereby air flow is slower in use outwards of the groove(s) than inwards, between the groove(s) the slit or aperture line.
• one opposed member is curved, preferably at least partially circularly cylindrically, it can be plain with neither rebate nor groove, particularly where the curved member is a bearing member inside the curvature of a web passing over it.
• the other opposed member can be complementarily curved, but need not be.
• the inner opposed member has a central slit or aperture array for air to provide isolation of liquid on either side, with further apertures for respective liquids up- and down-stream of the air slit or array.
• I should emphasise that I use "isolation" as in isolation of liquid on opposite sides of a liquid removal air knife to refer to the situation where there are two liquids, one on one side and the other on the other, which are maintained isolated by removal of the up-stream liquid from flowing into the air knife as the web moves into it and prevention of the downstream liquid from flowing back up-stream from the downstream side of the air knife.
• the liquid removal provides their isolation from each other.
• grooved air knives and rebated air knives or indeed grooved sides of an air knife and a rebated side of an air knife will normally be used in different circumstances; that is to say where liquid is in contact with a side of the air knife, that side will have a groove, whereas where liquid is not in contact with that side, it will have a rebate.
• the airflow will normally be symmetrical on both sides of the web and on the upstream and downstream side of the air knife. It therefore tends to support the web centrally of itself, with the central portion of the air knife functioning as an air bearing.
• the liquid contributes to the bearing support of the web centrally of the opposed members. The liquid tends to enter and be expelled again and in the process assists in keeping the web spaced from the opposed members.
• incorporation of grooves into the opposed surfaces can allow the web to flutter into contact with the opposed members. In such situations, it is preferable to use the rebated air knives or a rebated side of the air knife.
• the rebated opposed members provide less opportunity at their edges for the web to flutter into contact with the opposed members.
• the air is supplied in the air knives to the web via slits, it travels up and down stream of the web movement along the web on both sides.
• the gap between the opposed surfaces, less the thickness of the web is substantially equal to the width of the slits supplying the air. This travels to the web and then splits in two, on each side of the web, and in doing so requires only half the cross-sectional flow area to maintain similar flow conditions. This is provided by the half the same sized gap being available on opposite sides of the web.
• the opposed surfaces at the lands outwards of the grooves is preferably greater than at the inwards lands.
• the length of land from the slit to the groove and from the slit to the rebate is preferably substantially the same, whereby the bearing support of the web is similar up- and down-stream without a tendency for the web to touch the opposed surfaces.
• Conveniently plain surface portions are provided between slits or aperture lines, whereby the air flow from the respective slits / aperture lines being directed respectively outwards to ensure even airflow both up- and down-stream.
• the groove(s) / rebate(s) are provided outwards of the two slits / aperture lines.
• the opposed members can be each comprised of three parts, complementer ily machined at joint faces and fixed together to provide one of the opposed members,
• the opposed members can be each comprised of one part or three parts, complementarily machined at joint faces and fixed together to provide one of the opposed members,
• Figure 1 is a cross-sectional side view of web processing apparatus including air knives in accordance with the invention
• Figure 2 is a similar view on a larger scale of a washing tank of the apparatus with the air knives up- and down-stream of it;
• Figure 3 is a similar view again on a larger scale still of the downstream air knife
• Figure 4 is a perspective cross-sectional view of one of air knives per se
• Figure 5 is a scrap view of the air knife of Figure 4 showing grooves in accordance with the invention.
• Figure 6 is a cross-sectional diagram of another embodiment of a treatment bath and wash tank incorporating liquid removal apparatus of the invention.
• Figure 7 is a scrap view of a liquid removal and isolation air knife included in the embodiment of Figure 6;
• Figure 8 is a similar view of a combined air knife and liquid bearing
• Figure 9 is a view similar to Figure 6 of a horizontal arrangement of wash stations including air knives of the invention.
• Figure 10 is a view similar to Figure 4 of another variant air knife.
• Figure 1 1 is a view similar to Figure 8 of a further variant air knife.
• web treatment apparatus 1 has two process tanks 2,3 , each with respective upper and lower bearing fluid bearings 21 ,22; 31 ,32.
• a web 4 passes sinuously around them for treatment with chemical solution 23 in tank 2 and washing with water 33 in tank 3.
• Respective air knives 5,6 are provided at the outlet from tank 2 / inlet to tanks 3 and at the outlet from tank 3.
• the web 4 is passed around a plurality of other fluid bearings 10, which guide it in and out of the tanks.
• Each air knife is comprised of four parts, up- and down-stream parts 71,72 fixed together as a lower member 7 and like parts 81 ,82 fixed together as an upper member 8.
• the up-stream parts 71 ,81 have plain mating faces 73,83; whilst the down-stream parts 72,82 have machined faces 74,84 providing air supply plenum chambers 75,85 air supply slots 76,86, inner plenum chambers 77,87 and air knife slits 78,88.
• Non-shown means is provided for supply of air to the plenum chambers 75,85 whereby extended air jets exit the slits 78,88 towards each other. They impinge on the web when between the air knife members.
• the air flows along the top and bottom 41,42 faces of the web.
• the air flow exits the air knife in the up- and down-stream direction, passing out from between opposed faces 79,89 of the knife members. In doing so the air blows away any droplets tending to be drawn in between the members.
• the grooves comprise up- and down-stream, opposed semi-circular grooves 91,92 in the opposed faces 79,89. I believe that they operate as plenum chambers thoroughly equalising the pressure and flow of the air over the faces 41 , 42 of the web 4 outwards of them.
• the opposed faces are slightly relieved outwards of the grooves, where their separation 101 is greater than it 102 is inwards of the grooves.
• FIG. 6 another web processing apparatus has a process tank 202, with an inlet air bearing 210 with an array of air nozzles 21 1 over its surface guiding the web 204 passing over it into the process tank.
• the bearing is supplied with filtered air pressurised somewhat above atmospheric pressure.
• the air can be processed to the standard known as CDA air, Clean, Dry Compressed Air. It issues from the nozzles creating an air bearing layer enabling the web to pass over the bearing without contacting it.
• the tank has respective upper and lower liquid bearing bearings 221,222. These are supplied with liquid 223 with which the web is being processed in the tank through like nozzles (not shown), the supplied liquid being under pressure and creating a bearing film for passage of the web along a serpentine path around the bearings, without touching them.
• the web 204 passes to a liquid isolating air knife 206.
• its arrangements above and below its air knife slits 2061 differ.
• its opposed members 2062 have opposed grooves 2063 in their opposed faces 20641,20642. The grooves act to steady the flow of CDA air upwards such that wash liquid 233 present above the air knife does not penetrate between the opposed members 2062 of the air knife.
• the opposed surfaces are relieved, forming rebates 2065.
• wash liquid transfer bearings 2031 are provided up-stream of a wash tank 203.
• Wash liquid 233 typically de- ionised water, is pumped to the bearings, forming bearing films over them. Some of the liquid runs back down the web to the air knife 206, where it runs around the edges of the web to begin washing the other side of the web.
• the web passes into a first portion 2032 of the wash tank 203. Here it passes around another bearing 2034 provided with the wash liquid, above the normal depth 2036 of the wash water in the tank. Thence the web passes up to a compound bearing and air knife 207.
• This has a bearing cylinder 2071 , divided internally into two wash liquid passages 20721 , 20722 with a central air passage 2073 between them. Each has bearing nozzles 2074.
• an air knife opposed member 2075 having a central air knife slit 2076 and up- and down-stream rebates 2077.
• the air flow isolates the wash liquids of the respective portions 2032,2033 of the wash tank 203. Any wash liquid carried up by the web on to the top of the web on the cylinder 2071 is blown back at the up-stream rebate 2077. Equally whilst the same liquid is pumped to the up-stream passaged 20721 and out through its nozzles, the air from the central passage 2073 blows this liquid back preventing it passing the slit 2074.
• wash liquid Whilst the same wash liquid can be pumped to the passage 20722, this can also be kept separate, in the compound bearing and air knife 207 and indeed in the second portion 2033 of the wash tank, improving the washing. In like manner, the air from the central passage tends to blow back any liquid from the second passage
• the bearing liquid from the passage 20722 and its nozzles 2074 passes into the second tank portion 2033.
• the web passes around another wet bearing 2037 and up to an air knife 208.
• the air knife 208 has upper and lower rebates 2081 analogous to the rebates 2065. Thence the web passes to an air bearing 209 and on to a subsequent treatment station or to a reeling station (neither shown).
• FIG. 9 shows a pair of washing stations with a 301 ,302, such as shown in my British patent No 2,459,055, each having upper and lower, up- and down-stream flow path defining plates 3011,3012,3013,3014; 3021,3022,3023,3024, with double, staggered wash liquid slits 3015;3025.
• the web 304 passes between the plates and the jets.
• Air knives 305; 306; 307 are arranged up-stream of between and downstream of the washing stations.
• the air knife 306 between the stations 301,302 has grooves 3061, 3062 in its opposed members and chamfered up- and down-stream edges 3063.
• the arrangement is such that the edges of the wash station plates are close to the air knife members so that wash liquid flows onto the top of the top plates and is held from running freely from beneath the web, whereby web is exposed to the wash liquid for as long as possible.
• the chamfers of the air knives have the wash liquid between them and the web.
• the grooves set in from the chamfers are effective in providing a uniform air flow from between the opposed members, whereby the liquid does not flow into the air knives past the chamfers.
• the air knives 305,307 have similar grooves at their sides facing the wash station plates. At their outer sides, they have rebates, such as the rebates 2065, 2077, 2081. The lands between them and the central air knife slits as between the grooves and the air knife slits, whereby the air flow from the slits is divided to flow both upstream and down-stream. Two further variants are shown in Figures 10 and 11.
• Figure 10 is of three part construction as opposed to the two part construction shown in Figure 4.
• the outer parts 171,172 with the grooves 192 are the same, except being mirror images of each other, in that each has a machined faces 174 providing an air supply plenum chamber 175, air supply slots 176, an inner plenum chamber 177 and an air knife slit 78.
• These outer parts but against a plain innermost part 190.
• two air knife slits are provided, supplied with the same air.
• the innermost part and the outer parts are flush across the slits and the inner most part is plain at the web passage.
• Figure 1 1 shows a two slit arrangement incorporated into combined air knife and bearing similar to that in Figure 8.
• a central plate 501 performs the same function as the innermost part 1 0. However it has a grooved passage surface 502. This is to guard against contact between the web and the central plate.
• Two mirror image outer parts 503,504, conveniently 3D printed, are formed with a plenum space 505 against each side the central plate, slit formations 506 and outer grooves 507. Air is supplied to the plenum spaces in use to separate liquid supplied to outer passages 508,509 and providing bearing action via nozzles 510.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Cleaning In General (AREA)
• Drying Of Solid Materials (AREA)

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Applications Claiming Priority (4)

Publications (1)

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Citations (8)

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• 2016
  • 2016-11-02 KR KR1020187015107A patent/KR20180078278A/ko not_active Ceased
  • 2016-11-02 JP JP2018541576A patent/JP6984812B2/ja active Active
  • 2016-11-02 WO PCT/GB2016/053395 patent/WO2017077291A1/en not_active Ceased
  • 2016-11-02 CN CN201680076531.6A patent/CN108449936B/zh active Active
  • 2016-11-03 TW TW105135698A patent/TWI760316B/zh active

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