BUBBLE DIFFUSER OF FLEXIBLE POROUS PLASTIC

UK Patent n₉,GB .... 2095123 B[strike]SC[/strike]I[strike]CNCC REPEMNCF I IRRA[/strike]S[strike]If[/strike] (54) Title of invention Apparatus for introducing a gas into a liquid or a liquid-solids mixture (51) INT CL⁴;B01F 3/04 5/04 (21) Application No (73) Proprietors Bergwerksverband GmbH,Franz-Fischer-Weg 61 (22) Date of filing 4300 Essen 1324 Jul 1981Federal Republic of GermanyRuhrkohleAG, (30) Priority data Rellinghauserstrasse 14300 Essen 1 (31) 3111500Federal Republic of Germany(32) 24 Mar 1981(33) Fed. Rep. of Germany (DE) (43) Application published (72) Inventors 29 Sep 1982Albert BahrHans Ludke (45) Patent published Friedrich Wilhelm Mehrhoff3 Apr 1985Karl Legner (52) Domestic classification (74) Agent and/or B1C122 501 628 691 AU Address for Service Marks & Clerk, (56) Documents cited 57—60 Lincoln's Inn FieldsGBS 2015361London WC2A 3LSGB 1572625GB 1568799GB 1514577GB 1444476GB 1027659GB 0743697 (58) Field of search B1C (21) Application No (73) Proprietors Bergwerksverband GmbH,Franz-Fischer-Weg 61 (22) Date of filing 4300 Essen 1324 Jul 1981Federal Republic of GermanyRuhrkohleAG, (30) Priority data Rellinghauserstrasse 14300 Essen 1 (31) 3111500Federal Republic of Germany(32) 24 Mar 1981(33) Fed. Rep. of Germany (DE) (43) Application published (72) Inventors 29 Sep 1982Albert BahrHans Ludke (45) Patent published Friedrich Wilhelm Mehrhoff3 Apr 1985Karl Legner (52) Domestic classification (74) Agent and/or B1C122 501 628 691 AU Address for Service Marks & Clerk, (56) Documents cited 57—60 Lincoln's Inn FieldsGBS 2015361London WC2A 3LSGB 1572625GB 1568799GB 1514577GB 1444476GB 1027659GB 0743697 (58) Field of search B1CoN>O CD CJ1hO GODOLONDON THE PATENT OFFICE k y y d 1L t)i >^0^9(^3 - i - APPARATUS FOR INTRODUCING A GAS INTO A LIQUID OR A LIQUID-SOLIDS MIXTURE_______________________________The invention relates to apparatus for introducing agas intoa liquid or a liquid-solids mixture with a view to achemicalor physical reaction, for example for gasifying in aflotation system.The sintered ceramic material or metal used according to German Patent Specification 24 20 482 as bubble generators in conjunction with a flotation system suffer from the disadvantage that they 10 are blocked by the smallest particles in the slurry during operation and more particularly owing to sedimentation in the event of operational breakdowns. Completely homogeneous gasifying required for a chemical or physical reaction and absolutely necessary for the ensuing separating operation cannot be ensured.15 The present invention provides apparatus for introducing a gas into a liquid or a liquid-solids mixture with a view to chemical or physical reaction, comprising a duct for carrying a stream of the liquid or mixture, the duct having an inlet and an outlet between which the stream flows in an enclosed space, at least20 one surface inside the duct comprising a gasifying surface which extends substantially parallel with the flow direction of the stream, the or each gasifying surface being constituted by a bubble generator or generators of resilient and porous plastics material mounted in a given position, means being provided for supplying the gas to the bubble generator(s) at a given rate so the gas passes through the plastics material and enters the stream as bubbles., the plastics material being sufficiently flexible that, in use, movement of the plasticsmaterial takes place transversely to and in the plane of the30 gasifying surface, thereby resulting in temporary changes inpore diameter. - 2 - One or more rows of bubble generators, constructed as hoses and disposed transversely to the flow direction, may be provided in dependence on the gas quantity to be supplied to the gas discharging area.5 Two end regions of a bubble generator can be connected to respective gas supply ducts to ensure improved and more uniform introduction of gas.The technological progress of the invention is due mainly to the fact that, as a result of the resilient construction of10 the bubble generator, movement thereof is made possible as a result of flow and vortex formation so that sedimentation or other blockages on the surface of the bubble generator, due to operational breakdowns, are avoided and complete homogeneous gasifying is made possible without malfunctioning. The motion15 results in temporary changes of the pore diameter so that foreign bodies which have penetrated are removed and simultaneously prevents substantial wear.The invention will be described further, by way of example, with reference to the accompanying drawing, whose sole Figure 20 shows a section through apparatus for introducing a gas into a slurry.The illustrated gasifying apparatus 5 comprises a box-like, enclosed construction in which hoses of resilient and porous high-density polyethylene are disposed transversely to the flow - 3 -direction to function as bubble generators 10.The apparatus 5 has, at the top, a connecting socket 1 with a flange 2 for connection to a slurry duct, and, at the bottom, a connecting socket 3 with a flange 4 for connection, for example, 5 to a separating device required in a flotation plant. Air or another gas is supplied to the bubble generators 10 from gas supply ducts 6 and 7. (It is possible to omit the duct 7.)In the illustrated embodiment, four hose-like bubble generators 10 arranged transversely to the flow direction are disposed 10 between plenum chambers 8, 9 interposed between the gas supply ducts 6 and 7 and the bubble generators 10, which are suitably retained at their ends, so that pressure surges in the gas supply are avoided and at the same time an adequate gas volume flow is ensured.15 The bubble generators 10 are arranged in one or more rows, one behind the other and one below the other, so as to form gasifying surfaces parallel with the slurry stream. The number of bubble generators 10 disposed one beneath the other and in rows adjacently to each other depends on the slurry or gas throughput.20 According to another embodiment (not shown) it is feasible to arrange the bubble generators 10 in the form of one or more bundles, parallel with the flow, thus again providing a gasifying surface or surfaces extending parallel with the flow.- wThe bubble generators 10 need not necessarily be of hose form; it is feasible for the bubble generators 10 to be constructed, for example, as plate-like chambers arranged parallel with each other in the flow direction.5 The bubble generators 10 of hose construction, in the embodiment illustrated, have an internal diameter of at least 3 mm and a pore diameter distribution varying around a mean value between 2 and 50 jm. Given these dimensions and a flow velocity of the slurry of at least 0.5 m/s and a corresponding gas velocity,10 the thickness to be gasified by the gasifying surface should have a minimum value of 4 mm and a maximum value of 20 mm. The distance of the bubble generators 10 from each other should accordingly also be a minimum of 4 mm and a maximum of 20 mm, also measured transversely to the flow.15 According to another embodiment (not shown) it is feasible to allow the slurry to flow through the resilient porous hoses (bubble generators 10) and simultaneously to allow the gas to enter the hoses under pressure from the outside to the inside, so that the gas bubbles are formed on the inner surface of the20 hoses.- 5 -CI aims:-1.Apparatus for Introducing a gas into a liquid or a liquid-solids mixture with a view to chemical or physical reaction, comprisinga duct for carrying a stream of the liquid or mixture, the duct 5 having an inlet and an outlet between which the stream flowsin an enclosed space, at least one surface inside the duct comprising a gasifying surface which extends substantially parallel with the flow direction of the stream, the or each gasifying surface being constituted by a bubble generator or generators of 10 resilient and porous plastics material mounted in a given position, means being provided for supplying the gas to the bubble generator(s) at a given rate so that the gas passes through the plastics material and enters the stream as bubbles, the plastics material being sufficiently flexible that, in use, 15 movement of the plastics material takes place transversely to and in the plane of the gasifying surface, thereby resulting in temporary changes in pore diameter.2.Apparatus as claimed in claim 1, including at least one row of bubble generators, each bubble generator being in the20 form of a hose arranged transversely to the flow direction of the stream, the row extending parallel with the stream.3.Apparatus as claimed in claim 1, including bubble generators constructed as a bundle of adjacent hoses extending parallelwith the flow direction of the stream.- 6»-4.Apparatus as claimed in claim 1, including at least one bubble generator in the form of a plate-like chamber extending parallel with the flow direction of the stream.5.Apparatus as claimed in any of claims 1 to 3, in which5 the or each bubble generator has two ends, each end being connected to a gas supply duct of the gas supplying means.6.Apparatus as claimed in claim 5, in which at least one chamber is disposed between each of the gas supply ducts and a plurality of the bubble generators.10 7. Apparatus as claimed in claim 1, in which the duct comprises a section consisting of one or more hoses through which the stream passes, the hose(s) being of the saidresilient and porous plastics material, the gas supplying means being arranged to supply the gas under pressure to the exterior of the hose(s).15 8. Apparatus as claimed in any of claims 1 to 6, in which the plastics material has a mean pore diameter of 2 to 50 /im.9. Apparatus as claimed in any of claims 1 to 8, in which the plastics material is high-density polyethylene.³aas into a liquid or a liquid-"•^rence to.