EP0649389A1 - Diffuseur de fluide - Google Patents
Diffuseur de fluideInfo
- Publication number
- EP0649389A1 EP0649389A1 EP19930913301 EP93913301A EP0649389A1 EP 0649389 A1 EP0649389 A1 EP 0649389A1 EP 19930913301 EP19930913301 EP 19930913301 EP 93913301 A EP93913301 A EP 93913301A EP 0649389 A1 EP0649389 A1 EP 0649389A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- diffuser
- tube
- perforations
- fluid
- diffuser according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000012530 fluid Substances 0.000 title claims description 79
- 239000000463 material Substances 0.000 claims abstract description 56
- 229920003023 plastic Polymers 0.000 claims abstract description 8
- 239000004033 plastic Substances 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 8
- 239000010865 sewage Substances 0.000 claims description 6
- 238000010276 construction Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 abstract description 8
- 239000010959 steel Substances 0.000 abstract description 8
- 239000011148 porous material Substances 0.000 description 16
- 239000012528 membrane Substances 0.000 description 9
- 238000007789 sealing Methods 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000005038 ethylene vinyl acetate Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- 239000004800 polyvinyl chloride Substances 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 210000003128 head Anatomy 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 210000000936 intestine Anatomy 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000012858 resilient material Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000002679 ablation Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000005276 aerator Methods 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
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- 230000009977 dual effect Effects 0.000 description 1
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- 230000004907 flux Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
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- 229920001179 medium density polyethylene Polymers 0.000 description 1
- 239000004701 medium-density polyethylene Substances 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/165—Making mixers or parts thereof
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/20—Activated sludge processes using diffusers
- C02F3/201—Perforated, resilient plastic diffusers, e.g. membranes, sheets, foils, tubes, hoses
-
- 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
- B01F23/23114—Mounting the bubbling devices or the diffusers characterised by the way in which the different elements of the bubbling installation are mounted
- B01F23/231142—Mounting the gas transporting elements, i.e. connections between conduits
-
- 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
- B01F23/23115—Mounting the bubbling devices or the diffusers characterised by the way in which the bubbling devices are mounted within the receptacle
- B01F23/231152—Mounting the bubbling devices or the diffusers characterised by the way in which the bubbling devices are mounted within the receptacle the bubbling devices being supported, e.g. on cables or laying on the bottom
-
- 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
- B01F23/231231—Diffusers consisting of rigid porous or perforated material the outlets being in the form of perforations
-
- 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
- B01F23/23124—Diffusers consisting of flexible porous or perforated material, e.g. fabric
-
- 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
- B01F23/23124—Diffusers consisting of flexible porous or perforated material, e.g. fabric
- B01F23/231241—Diffusers consisting of flexible porous or perforated material, e.g. fabric the outlets being in the form of perforations
-
- 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
- B01F23/231265—Diffusers characterised by the shape of the diffuser element being tubes, tubular elements, cylindrical elements or set of tubes
-
- 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
- B01F23/231266—Diffusers characterised by the shape of the diffuser element being in the form of rings or annular elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
- B01F35/10—Maintenance of mixers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Definitions
- This invention relates to a diffuser, for example an aerator, for delivering air or another liquid or gaseous fluid in finely divided form to a surrounding medium. More particularly, the invention relates to a fluid diffuser for use in submerged conditions, for example for treating sewage or polluted lakes or waterways with air.
- the prior diffuser also has the disadvantage that when used in submerged conditions, for example for aerating sewage or polluted waterways, the requisite negative buoyancy aid, which may be a metal filament in the form of a steel cable, can most easily be associated with the tubular diffuser by accommodating it within the bore of the tube thereby occluding a significant proportion of the volume of the tube which would otherwise be available for the passage of fluid. It is an object of the present invention to provide a fluid diffuser for use in submerged conditions, in which the aforesaid disadvantages are obviated or mitigated.
- a fluid diffuser for use in submerged conditions, comprising a flexible member having opposed walls defining a perforated fluid delivery tube, and a negative buoyancy aid held captive by said walls in spaced relationship with said tube.
- Said flexible member may be made from a flexible material, for example a heat-sealable synthetic plastics material.
- Preferred heat-sealable synthetic plastics materials include polyvinyl chloride, polyethylene and ethylene vinyl acetate.
- the perforated fluid delivery tube is arranged to have a circular cross-section when a fluid is flowing therein.
- the perforated fluid delivery tube is arranged to collapse, suitably into a substantially flat state, when a fluid is not flowing therein.
- the fluid delivery tube is in a relaxed state when collapsed.
- Said flexible member is preferably elongate. More preferably, said flexible member is in the form of a flexible material strip.
- said opposed walls of said flexible member are made of the same material.
- the opposed walls are of the same thickness.
- each of said opposed walls is of perforate construction.
- opposing parts of said fluid delivery tube are perforated.
- the opposed walls of the fluid delivery tube may be made from a single sheet of material and/or may be made from a flattened tube.
- the opposed walls are made from separate sheets of material.
- inwardly facing surfaces of said separate sheets are joined to one another, for example, by heat-sealing, in order to define said perforated fluid delivery tube.
- said separate sheets are perforated to form longitudinal zones of perforations at corresponding locations before being joined at opposite sides of said zones to form said tube.
- the perforations of said perforated fluid delivery tube are arranged to be self-closing when not subject to internal pressure. This may be achieved by non-ablative perforation of an appropriate material.
- Mechanical needling__involving piercing without material removal results in the formation of perforations which are closed when the tube is not in a relaxed condition, i.e. when it is not subject to tension as a result of internal fluid pressure above a predetermined threshold level.
- the performance of a diffuser having self-closing perforations as described above may be improved by adapting the diffuser such that the proximity of the perforations and the elasticity of the tube material are such that internal operating pressures cause asynchronous opening and closing of the perforations.
- perforations of the fluid delivery tube taper inwardly towards the centre of the tube.
- the perforations may be trapezoidal or, preferably, frusto- conical in shape.
- said perforations may be arranged to produce bubbles of less than 4 ⁇ in diameter.
- Said perforations are preferably arranged to produce bubbles less than 2 ⁇ m in diameter.
- Said perforations are preferably equally spaced.
- Said negative buoyancy aid is preferably held captive between two opposing portions of said flexible member.
- said negative buoyancy aid is preferably elongate and is held captive between elongate portions of said flexible member.
- Said elongate portions are preferably defined by portions of said flexible member which are joined to one another, for example, by heat-sealing.
- said flexible member is made from separate sheets of material, preferably inwardly facing surfaces of separate sheets are joined to one another in order to define said elongate portions.
- Said negative buoyancy aid is preferably held captive by said walls along substantially the whole extent of the flexible member.
- Said negative buoyancy aid is preferably enclosed, suitably along substantially its whole extent, by said flexible member.
- the perforated fluid delivery tube and the negative buoyancy aid are movable relative to one another.
- the fluid delivery tube and negative buoyancy aid may pivot relative to one another about an elongate axis defined between them.
- Said elongate axis may be defined by portions of the flexible member which are joined to one another, as described above.
- Said negative buoyancy aid is preferably flexible.
- Said negative buoyancy aid preferably comprises a metal filament, for example, a steel cable or flattened strip.
- the fluid diffuser may include buoyancy adjustment means for altering the buoyancy of the diffuser.
- Said buoyancy adjustment means may be provided if it may be desirable to vary the submerged depth of the fluid diffuser.
- Said buoyancy adjustment means may comprise a further, unperforated tube which is inflatable to a variable extent so as to alter the buoyancy of the diffuser.
- Opposed walls of said flexible member preferably define the walls of the unperforated tube.
- a buoyancy adjustment means as described may be particularly useful in the case of a submergible boom as_described in U.K. Patent Application No. 9116072 (relating to a submergible boom for controlling oil spillages) because the boom may be positioned at any required depth depending upon the weather conditions or it may be positioned at a suitable depth below an oil spillage.
- the fluid diffuser preferably further includes tethering means for tethering the diffuser in position in use.
- the negative buoyancy aid is in the form of a metal filament
- said metal filament may extend beyond the ends of the flexible member and be equipped with end fittings for tethering the diffuser in a position of use.
- the fluid diffuser preferably includes means for removably securing a fluid delivery line.
- the diffuser described above is suitably at least 2 metres in length. Preferably, the diffuser is at least 5 metres in length. The diffuser may be greater than 10 metres in length.
- the diffuser is preferably sufficiently flexible such that is may be stored in a rolled up state; for example, it may be stored on a reel in the manner of a hose.
- a fluid diffuser for use in submerged conditions, comprising a perforated fluid delivery tube with tube perforations which are self- closing when not subject to internal pressure, characterised in that the proximity of the perforations and the elasticity of the tube material are such that internal operating pressures cause asynchronous opening and closing of the perforations.
- adjacent perforations exhibit asynchronous opening and closing.
- Non-adjacent perforations may exhibit synchronous opening and closing.
- the fluid diffuser of the second aspect may include any feature of the fluid diffuser of the first aspect.
- a method of diffusing a fluid into a surrounding medium for example air into sewage comprising placing a diffuser according to the first or second aspects into said medium and introducing the fluid into the diffuser at a pressure such that the fluid is forced through the perforations of the fluid delivery tube into the surrounding medium.
- a part of the diffuser for example a negative buoyancy aid thereof (when provided) may rest upon the bottom of a container, for example, a river or sewage tank, which contains the medium.
- a container for example, a river or sewage tank, which contains the medium.
- the diffuser is not supported by any external support means.
- a fluid diffuser according to the first or second aspects for diffusing a fluid into a surrounding medium.
- a method of manufacturing a fluid diffuser comprising forming a perforated fluid delivery tube using a flexible member and arranging said flexible member so as to captivate a negative buoyancy aid in spaced relationship with said tube.
- the flexible member is preferably formed from two sheets of material.
- the two sheets of material are arranged both to form said perforated fluid delivery tube and to captivate said negative buoyancy aid.
- the method preferably includes the step of perforating the flexible member before formation of the tube and/or before captivation of said negative buoyancy aid.
- the perforations are preferably formed when the material of the flexible member is held taut, but is unstretched.
- Fig. 1 is a side view of a perforating machine in use
- Fig. 2 is a plan view corresponding to Fig. 1;
- Fig. 3 is a side view of a machine for making one embodiment of fluid diffuser
- Fig. 4 is a section on line IV-IV of Fig. 3;
- Figs. 5 and 6 are diagrammatic views showing this embodiment of the fluid diffuser in the inflated (fluid delivery) and non-inflated conditions respectively;
- Fig. 7 shows the same fluid diffuser when submerged;
- Figs. 8 to 10 show different designs of the fluid diffuser
- Fig. 11 shows the supply (air inlet) end of one embodiment of fluid diffuser in accordance with the invention
- Figs. 12, 13 and 14 show alternative designs for the other end of the fluid diffuser
- Fig. 15 shows an alternative embodiment of the fluid- diffuser in the in-use condition
- Fig. 16 shows a further embodiment with an alternative negative buoyancy aid
- Fig. 17 shows an alternative design of fluid diffuser made from a perforated tube
- Fig. 18 shows the perforated tube from which the fluid diffuser of Fig. 17 is made
- Fig. 19 shows an alternative design of fluid diffuser in which the fluid delivery tube is in the form of concentric rings
- Fig. 20 is a section of Fig. 19 showing the diffuser in use.
- Fig. 21 illustrates in diagrammatic form one mode of operation of perforations of a fluid diffuser.
- the fluid diffuser of the invention may be used for delivering any fluid (whether gas or liquid) to any (preferably denser) fluid in which it is submerged
- any fluid diffuser is to deliver air into a liquid, for example water or sewage
- the diffuser is used for delivering air into water.
- the illustrated embodiment of fluid diffuser comprises an elongate material strip (of which only a short section is shown) made from two separate sheets 1, 2 of synthetic plastics material, for example plasticised polyvinyl chloride, low or medium density polyethylene, or ethylene vinyl acetate which are separately perforated in two lateral zones la, lb and 2a, 2b (as described in greater detail below) and then heat-sealed together at their longitudinal edges 3_, 4 and at intermediate positions 5, 6 to either side of a steel cable 7 positioned between the sheets 1 and 2.
- synthetic plastics material for example plasticised polyvinyl chloride, low or medium density polyethylene, or ethylene vinyl acetate which are separately perforated in two lateral zones la, lb and 2a, 2b (as described in greater detail below) and then heat-sealed together at their longitudinal edges 3_, 4 and at intermediate positions 5, 6 to either side of a steel cable 7 positioned between the sheets 1 and 2.
- the flexible material strip so formed thus has opposed walls formed by the sheets 1, 2 incorporating fluid delivery tubes 8, 9 with perforations provided by the coinciding perforated zones la, 2a and lb, 2b.
- the steel cable 7 provides a negative buoyancy aid which is trapped and sealed in position by the heat-sealed portions 5, 6.
- the strip material In the relaxed out-of-use condition shown in Fig. 6, the strip material is flat and can readily be stored on a supply reel.
- air is supplied to the tubes 8, 9, they distend into the inflated condition shown in Fig. 5 and air passes into the surrounding medium through the tube per orations.
- the fluid diffuser is shown submerged in water 10 with the encased steel cable 7 resting on a bottom surface and the air delivery tubes 8, 9, floating upwardly with the heat- sealed portions 5, 6 acting as hinges.
- the tubes 8, 9 are subjected to a pressure of up to 4 psi say 1 to 4 psi in excess of the ambient pressure. This pressure differential is sufficient to open the pores in the tube 8, 9 thereby releasing numerous fine air bubbles generally indicated at 10.
- Figures 1 to 4 show how the fluid diffuser of Figs. 5 to 7 may be manufactured.
- Figs. 1 and 2 show a perforating machine for perforating a strip 1 or 2 of synthetic plastics material intended to form the walls of the diffuser strip.
- the machine comprises pay-off and take-up wheels 11, 12 for the plastics strip material 1, 2 which is trained between pairs of tensioning rollers 13, 14 between which are mounted on a common shaft twin needle wheels 15, 16.
- the tensioned strip 1,2 runs around the underside of the needle wheels 15, 16 which rotate at high speed to perforate the strip 1, 2 during its travel between the reels 11, 12 so as to provide the two perforation zones la, 2a, and lb, 2b mentioned above.
- Each needle wheel is provided on its periphery with numerous fine radially directed needles designed to pierce the strip material 1, 2 without any ablation, i.e. without removing any material.
- the perforations produced by the fine needles will be small, downwardly tapered (as seen in Fig. 1) and self- closing in the sense that when the material is in the relaxed condition, or subject to a tension below a threshold value, the holes close automatically by virtue of the resiliency of the surrounding material. This self- closing or self-healing feature is known in other applications and is therefore not further described.
- Figs. 3 and 4 show a machine for making a flexible material strip intended as a fluid diffuser.
- Two delivery rolls 17, 18 (which may be take-off rolls 12 of the machine of Figs 1 and 2) are arranged to deliver perforated strip 1 with perforation tracks la, lb and perforated strip 2 with correspondingly positioned perforation tracks 2a, 2b to pairs of edge guide rollers 19, 20 and 21, 22 with the two pairs of each set 19, 20 and 21, 22 being spaced apart transversely for contact with opposite longitudinal edges of the travelling composite strip.
- Intermediate the guide roll of pairs 19, 20 and 21, 22 are two pairs of heat-sealing rollers 23, 24 which as seen in Fig. 4 likewise contact the opposite longitudinal edges of the travelling material strips so as to heat-seal these edges.
- a further pay-off roll 25 supplies steel cable 7 centrally between the material strips l, 2.
- the finished material strip is wound onto a take-up roll 27.
- the embodiment of Fig. 8 comprises three air delivery tubes 38, 39 and 40 with two interposed cables 37 and 37' held captive by flanking sealed portions 35, 36 and 35', 36'.
- the unperforated air tube 69 can be inflated to a required extent to vary the buoyancy characteristics of the diffuser of Fig. 15.
- the embodiment of Fig. 16 is similar to the embodiment of Fig. 9 except that the cables are replaced by flat metal strips 77, 77' and 77" positioned between the perforated air tubes 78, 79.
- Fig. 17 is similar to the embodiment of Figs. 5 and 6 except that instead of being made from two strips which are heat-sealed together it is made from a flat, perforated tube as shown in Fig. 18.
- a construction is acceptable if tube perforation poses no problems, for example if only one side of the tube requires to be perforated or if a single perforation operation involving piercing of both tube layers simultaneously is acceptable.
- Fig. 11 shows a possible design for the air supply end of the embodiment of Figs. 5 and 6.
- End fittings 27, 28 seal the ends of the air tubes 8, 9 and provide a connector for air supply pipes only one of which is shown at 29.
- the cable 7 extends from the end of the material strip and has an eye connector 7' for tethering the diffuser in a position of use.
- the opposite end of the diffuser may have a similar design as shown in Fig. 13 with an eye connector 7" but in this case the end fittings 27', 28' are simple stoppers and do not have the pipe connector extensions.
- An alternative design for the remote end of the diffuser is shown in Fig.
- FIG. 12 in which the stoppers 27', 28' can be omitted because the end of the flexible strip is flattened and heat-sealed.
- Fig. 14 A further variation is shown in which the cable stops short of the end of the diffuser and the heat-sealed end portion is provided with two eyes for use in tethering together the diffuser.
- the diffusers so far described are all of elongate construction and can be made to a wide range of designs depending upon the application of the diffuser.
- the number and weight of the metal filaments providing the negative buoyancy aids may be varied as may the number and size of the air delivery tubes. Additional features such as buoyancy tubes may be provided as described.
- a diffuser of appropriate length is run across a polluted river and tethered on both banks using the end fittings.
- the negative buoyancy aid ensures that the diffuser strip is held down onto the river bed even when air is supplied to the diffuser tube or tubes.
- FIGs. 19 and 20 An alternative design shown in Figs. 19 and 20 is of circular design with concentric air chambers and no negative buoyancy aid. If appropriate, the negative buoyancy aid may also be omitted from the other embodiments.
- the flexible material strip of the other embodiments- is replaced by a flexible material sheet.
- a negative buoyancy aid may be incorporated in the design of Fig. 19 and 20 by trapping a metal cable or strip between the opposed sheets between the concentric air chambers.
- the proximity of the perforations and the elasticity of the tube material may be selected such that internal operating pressures cause asynchronous opening and closing of the perforations.
- the perforations of the diffuser may not open simultaneously as might be expected when a predetermined internal threshold pressure is achieved.
- the desired effect may only be obtained if the perforations are closely spaced in material of suitable elasticity such that the lateral pressure exerted by air passing through one perforation exerts pressure on the land around that perforation thereby preventing closely adjacent pores from opening. Once the air, in the form of a bubble, has cleared the membrane the lateral pressure ceases thereby permitting adjacent pores to open and reversing the lateral pressure to close the first perforation.
- the phenomenon described does not exist when the land between the perforations is not stressed by the passage of air through the perforations, whether by reason of the distance between the perforations, lack of elasticity in the membrane, excessive pressure drop across the membrane, or otherwise.
- the phenomenon is also dependent upon perforations which are self-closing or self-healing when not subject to internal pressure.
- the perforations may open and close, i.e. oscillate, on a regular cycle with no perforation ever being fully open or closed.
- the cycle time or oscillating rhythm can be changed by varying the internal pressure. In order to ensure that all pores are simultaneously energised when pressure is applied to the fluid diffuser, stress within the system must be evenly distributed.
- the perforations should therefore be distributed with equal spacing in a regular pattern over the entire surface of the diffuser tube or at least within the perforation zones described with reference to the drawings.
- the material from which the diffuser tube is made should also be of consistent quality and thickness. Additionally, all the_perforations are preferably axially and geometrically aligned with the central axis of the tube when pressurised into its cylindrical form.
- the closely spaced perforations are interactive as described above with no pore ever being fully open or fully closed along its entire length.
- the internal end section of a perforation may be opened to admit a small parcel of air. This causes the stress in the adjacent wall material or land to rise compressively. Material rebound closes the perforation behind the air parcel so forcing the parcel further up the perforation repeating the stress and rebound process until the air parcel is ejected as a small bubble.
- the frequency of the stress/rebound process determines the size of the air parcel and hence the size of the bubbles that are released into the surrounding fluid in use.
- the action is similar to peristalsis in the human intestine except that muscular contraction of the intestine is replaced by elastic rebound of the tube material.
- the asynchronous opening and closing of perforations may be obtained using a diffuser tube made of synthetic plastics material, for example plasticised polyvinyl chloride, polyethylene or ethylene vinyl acetate.
- the Shore hardness ranges from 65 to 85 and the density of the perforations is 200 to 350 perforation per square inch.
- the thickness of the diffuser tube material varies depending on various factors, for example the hardness of the material, the design operating pressure and the size of the needles used.
- a typical wall thickness for a 3 inches diameter tube would be 0.015 to 0.020 inches with perforations obtained by using needles of diameter 0.028 inches with a tip tapered at an angle of 22.5°. Only the tip penetrates the membrane and not the needle shank.
- a preferred range of needle diameters is 0.020 inches to 0.032 inches shank diameter for all tube diameters.
- Fig. 21 illustrates the peristaltic action of the perforations as described above.
- a portion of the tube wall is shown in section through three perforations with the insert of the tube below the wall and the outside of the tube above the wall.
- Figs 21a and 21b show successive stages in bubble formation using a diffuser tube operating with a relatively low internal pressure and Figs. 21c and 21d show corresponding stages when a relatively high internal pressure prevails.
- the number of air parcels or bubbles reduces and their size increases as the pressure increases. Thus a low operating pressure produces a large number of small bubbles and a high operating pressure -produces a smaller number of large bubbles.
- the pores are not necessarily the same size as long as mixed pore sizes are maintained in equally spaced regular patterns.
- the same complex stress patterns mentioned above give rise to the regular oscillating pore cycle.
- two different bubble sizes are produced, one relatively larger than the other.
- This strategy may be useful in producing both relatively large bubbles for agitation purposes as well as smaller diffuser bubbles.
- the ratio of large bubble producing perforations to small bubble producing perforations is optimised to give the desired effect, preferably with a preponderance of small diffusion bubbles.
- the needle piercing may be adjusted so that incomplete perforation of the diffuser tube material is obtained. Most of the wall is pierced to leave a thin membrane at the inner end of the perforation. When the diffuser is first pressurised the thin sealing wall or membrane at the bottom of each perforation is ruptured to form a flap extending inwardly into the perforation. This flap controls air entering the perforation and acts as a non-return valve which assists in the prevention of fluid inflow when the diffuser is unpressurised.
- the diffuser tube material is transparent to facilitate inspection of perforation formation and the diffuser tube bore.
- the diffuser tube may have a dual wall construction.
- a relatively thin layer of more resilient material can be bonded to a relatively thick layer of less resilient material.
- the thick layer or substrate would be above 0.012 inches thick and the resilient thin layer would be 0.001 to 0.002 inches thick.
- the bonded laminate would be pierced as a single strip.
- the more resilient thin layer perforations would open up more than the thick layer perforations under pressure.
- the thin layer perforations govern the size of bubbles released.
- a very fine low pressure diffuser would result. This would be achieved, whilst still retaining the low stretch characteristics of the substrate which are useful in avoiding pore opening in hydraulically stressful conditions.
- Ultra-fine pores capable of working at very low internal pressures can also be achieved by lining pores of a pierced, very low elastic membrane. This can be achieved by dipping piercing needles in an appropriate solution of resilient polymer material immediately prior to piercing. The impressed needles would leave a coating of resilient polymer on the walls of the pores. The thickness of the coating could be a few microns. A light air blow immediately following the piercing/lining procedure would clear excess solution from the pores and dry out the resilient polymer coating the open pore mode.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Microbiology (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
- Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
Abstract
Un diffuseur de fluide destiné à être utilisé submergé comprend une bande allongée de matériau réalisée à partir de deux feuilles séparées (1, 2) d'un matériau plastique synthétique qui sont perforées séparément dans deux zones latérales (1a, 1b et 2a, 2b) et ensuite scellées à chaud sur leurs bords longitudinaux (3, 4) et sur des positions intermédiaires (5, 6) aux deux côtés d'un câble en acier (7) positionné entre les feuilles (1 et 2). Le câble en acier (7) est prévu pour alourdir le système. Lorsque de l'air est fourni aux tubes (8, 9), ils se dilatent et l'air passe dans le milieu environnant par les perforations des tubes. Différentes autres formes de diffuseurs sont également décrites, en particulier une qui est circulaire.
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB929212195A GB9212195D0 (en) | 1992-06-09 | 1992-06-09 | A diffuser |
GB9212195 | 1992-06-09 | ||
GB929212193A GB9212193D0 (en) | 1992-06-09 | 1992-06-09 | A fluid diffuser |
GB9212193 | 1992-06-09 | ||
PCT/GB1993/001196 WO1993025484A1 (fr) | 1992-06-09 | 1993-06-04 | Diffuseur de fluide |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0649389A1 true EP0649389A1 (fr) | 1995-04-26 |
Family
ID=26301036
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19930913301 Withdrawn EP0649389A1 (fr) | 1992-06-09 | 1993-06-04 | Diffuseur de fluide |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0649389A1 (fr) |
AU (1) | AU4341993A (fr) |
CA (1) | CA2137546A1 (fr) |
GB (1) | GB2267655A (fr) |
WO (1) | WO1993025484A1 (fr) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2279648B (en) * | 1993-07-07 | 1997-11-12 | Bridon Plc | Flexible elongate assembly for dispersing gas into liquid |
DE4412756C2 (de) * | 1994-04-13 | 1996-06-20 | Gore W L & Ass Gmbh | Schlaucheinheit und Verfahren zur Herstellung derselben |
DE19923593A1 (de) * | 1999-05-22 | 2000-11-23 | Gummi Jaeger Kg Gmbh & Cie | Verfahren zur Herstellung von feingeschlitzten Wasserbelüftern aus Gummi o. dgl. |
DE20001634U1 (de) * | 1999-10-06 | 2000-04-20 | UTA Umwelttechnik & -analytik GmbH Leipzig, 04318 Leipzig | Vorrichtung zum Belüften von natürlichen und künstlichen Gewässern, Behältern, Tanks und Becken |
US6957744B2 (en) * | 2003-01-24 | 2005-10-25 | Insta-Mix, Inc. | Nipple with multiple pinholes for baby bottle assembly |
CA2627301A1 (fr) * | 2005-10-26 | 2007-05-03 | Parkson Corporation | Panneau d'aeration souple et procedes d'utilisation |
US7806389B2 (en) | 2005-10-26 | 2010-10-05 | Parkson Corporation | Flexible aeration panel and methods of use |
JP5361332B2 (ja) * | 2008-10-30 | 2013-12-04 | 株式会社クボタ | メンブレン式散気装置 |
KR101899929B1 (ko) † | 2010-03-02 | 2018-09-19 | 애칼 에너지 리미티드 | 연료 전지 |
DE102014226134A1 (de) * | 2014-12-16 | 2016-06-16 | Rudolf Messner Umwelttechnik Ag | Luftverteiler zur Belüftung eines Wasservolumens, Luftverteilerfolie für einen solchen Luftverteiler sowie Verfahren zur Herstellung einer solchen Luftverteilerfolie |
EP3468926A4 (fr) * | 2016-06-12 | 2020-01-01 | Randall L. Tucker | Collecteur comprenant un bassin de retour et de limon, barboteur et procédé associé |
FR3075842B1 (fr) * | 2017-12-21 | 2020-10-23 | Vincent Conrard | Tapis producteur de bulles pour piscines |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB802374A (en) * | 1955-09-24 | 1958-10-01 | Distillers Co Yeast Ltd | Device for introducing gas into liquids |
DE1784398B1 (de) * | 1968-08-03 | 1970-12-10 | Danjes Dipl Ing Martin | Einrichtung zum feinblasigen Belueften von Abwasser |
US3677936A (en) * | 1971-03-10 | 1972-07-18 | Abraham G Bastiaanse | Liquid treatment method |
DE2261994A1 (de) * | 1972-12-19 | 1974-06-20 | Martin Dipl-Ing Danjes | Einrichtung zum feinblasigen belueften von abwasser |
US3988396A (en) * | 1973-11-02 | 1976-10-26 | Stannard Forrest B | Aeration tubing system |
US4029581A (en) * | 1974-12-26 | 1977-06-14 | Xodar Corporation | Aerating system |
DE3731998A1 (de) * | 1987-09-23 | 1989-04-06 | Jaeger Arnold | Vorrichtung zur wasserbelueftung |
GB9015448D0 (en) * | 1990-07-13 | 1990-08-29 | Lanmark Consultants Ltd | Improvements in or relating to flow control |
-
1993
- 1993-06-04 WO PCT/GB1993/001196 patent/WO1993025484A1/fr not_active Application Discontinuation
- 1993-06-04 EP EP19930913301 patent/EP0649389A1/fr not_active Withdrawn
- 1993-06-04 AU AU43419/93A patent/AU4341993A/en not_active Abandoned
- 1993-06-04 CA CA 2137546 patent/CA2137546A1/fr not_active Abandoned
- 1993-06-07 GB GB9311736A patent/GB2267655A/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO9325484A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU4341993A (en) | 1994-01-04 |
GB2267655A (en) | 1993-12-15 |
CA2137546A1 (fr) | 1993-12-23 |
WO1993025484A1 (fr) | 1993-12-23 |
GB9311736D0 (en) | 1993-07-21 |
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