| US4540487A | 1985-09-10 |
| 1. | A method of filtering a liquid, polluted liquid being fed to a filtering device (1) above a filter and a portion of the filtrate obtained in this way being reversed temporari¬ *j ly for a counter flushing and thereby a cleaning of the filtrate, c h a r a c t e r i z e d in that the polluted liquid is divided into partial flows, which are fed into each one of several cells (11,12,13,14), each one contai¬ ning a filter (28) , and in that the cell, which is subjec¬ ted to counter flushing, is shielded from a continued fee¬ ding of polluted liquid and simultaneously is connected to a flushing liquid outlet, whereas in the other cell or the rest of the cells the filtration process continues. |
| 2. | A method according to claim 1, c h a r a c t e r i z e d in that the filtrate in reference to each filter (28) is fed through an intermediate chamber (20,21,22,23) and sub¬ sequently through a preferably central common main chamber (9) , which contains a driving unit (46) with a pump (55) , which can be optionally connected to the cell, which is to be cleaned and the intermediate chamber of which by means of the driving unit is shielded from the main chamber and simultaneously is connected to the pressure side of the pump, and in that said driving unit simultaneously shields the cell from a continued feeding of polluted liquid arid allows a connection between the cell and the flushing li¬ quid outlet (61 or 62) . |
| 3. | A device designed to carry out the method according to claim 1, a filtration device (1) comprising a filter (28) , an inlet (30) for polluted liquid, a filtrate outlet (29) as well as means (46) for a temporary reversal of the li¬ quid flow and thereby a counter flushing and a cleaning of the filter, c h a r a c t e r i z e d in that the de¬ vice (1) is divided into a number of cells (11,12,13,14) , each of which is provided with its own inlet (34,35,36,37) for polluted liquid and its own filter (28) , and in that said means (46) is designed to simultaneously shield the cell, which is subjected to a counter flushing, from a con¬ tinued feeding of polluted liquid and to connect the cell to a flushing liquid outlet (61 or 62) as well as to allow at least one of the rest of the cells to continue the filt¬ ration process. |
| 4. | A device according to claim 3, c h a r a c t e ¬ r i z e d in that the filtration device (1) comprises a housing (2) , which is parallelepipedshaped or cylinder shaped and in which in a central area a cylindershaped main chamber (9) is located, the side wall (10) of which forms an inner limitation for said outwardly located cells (11,12,13,14) , which mutually are limited by vertical par¬ titions (15,16,17,18) , which extend between the respective housing walls (4,5,6,7) and said side wall (10), and in that the cells and the main chamber have a preferably com¬ mon bottom (3) as regards the bottom plane. |
| 5. | A device according to claim 4, c h a r a c t e r i z e d in that above the sections of the bottom (3) of the cells (11,12,13,14) a respective intermediate chamber (20,21,22, 23) is located for each cell, which is laterally limited by said housing walls (47) , said intermediate walls (15 18) and said main chamber wall (10) , the latter being pro¬ vided with an opening (24,25,26,27) , via which the respec¬ tive intermediate chamber communicates with the main cham¬ ber, the intermediate chambers also being limited upwards by a perforated sheet or the like (19) , on top of which said filter (28) is disposed. |
| 6. | A device according to claim 3, c h a r a c t e r i z e d in that the main chamber (9) preferably on a slightly high¬ er intermediate level and via an overflow (60) is connected to the filtrate outlet (29) , which extends outwards in a horizontal direction and through one of the cells, and in that the inlet (30) for polluted liquid is placed on a higher level than said outlet. |
| 7. | A device according to any of claims 36, c h a r a c ¬ t e r i z e d in that the inlet (30) for polluted liquid leads to a distributing groove (31) , which encloses the main chamber (9) and is provided with one of said inlet openings (34,35,36,37) for each cell (1114). |
| 8. | A device according to any of claims 37, c h a r a c ¬ t e r i z e d in that the flushing liquid outlet (61,62) is designed as a flushing groove (38,39), which preferably is common to several cells and has an overflow inlet edge (42,43) , preferably provided with cuts (44) and located at a slightly lower level than the upper limitation edge of the chamber (9) and the distributing groove (31) respecti¬ vely. |
| 9. | A device according to any of claims 38, c h a r a c t e r i z e d in that said means (46) for a temporary re¬ versal of the liquid flow comprises a driving unit, prefe¬ rably provided with a base plate (47) , which via a pivot (45) is rotatably mounted on the bottom (3) of the main chamber (9) and can be rotated by means of e.g. an elect¬ ric motor (52) , mounted on a lid (8) on the housing (2) , said driving unit comprising a connection part (49) with a nozzle (50) , designed to sealingly, on the main chamber side, enclose one of the openings (2427) to the interme¬ diate chambers (2023) and to feed reversed liquid to the selected intermediate chamber from either the main chamber or another intermediate chamber, e.g. by means of a pump (55) , preferably mounted on the base plate. |
| 10. | A device according to claim 9, c h a r a c t e r i z e d in that the connection part (49), which e.g. is horizontal, forms the lower part of a vertical transmission tube (48) , which part is fastened to the base plate (47) , in that the transmission tube at the top is connected to a turning de¬ vice (51) , which is connected to the driving motor (52) , in that the transmission tube, within the area of the tur¬ ning device, is connected to a pump conduit (54) , which leads to said pump (55) , and in that from said turning de¬ vice a mainly horizontal arm (57) extends, which with one end (58) supports a sealing element (59) , designed to sea lingly cover one of the openings (3437) to the cell, which is to be subjected to a counter flushing, said nozzle (50) simultaneously sealingly enclosing the intermediate cham¬ ber opening of the same cell. |
The present invention relates to a method of filtering a li¬ quid according to the preamble of patent claim 1. Also, the invention relates to a device, designed to carry out the method according to patent claim 1.
The invention particularly aims at a counter flushing of filters, which subsequent to a certain operating time will be filled with impurities and thereby less efficient.
A counter flushing is per se already known, which means that the direction of e.g. a water flow is reversed and that the purified water flow or another liquid flow is forced in the opposite direction through the filter. Attached im¬ purities are thereby removed from the filter, which impuri¬ ties generally are removed from a particular outlet in or¬ der to avoid that they from then on will interfere with the purification process.
The already known methods and devices, designed for this purpose, are often complicated and expensive to use, to ma¬ nufacture and to maintain, and generally they are impaired with the substantial drawback of temporary operating shut¬ downs, which implies inconveniences in a plurality of ob¬ vious respects.
The object of the present invention is to counteract and as far as it is feasible to overcome the inconveniences, with which the already known methods and devices are im¬ paired. Also, another object of the invention is to deve¬ lop the state of the art in this field and to render pos¬ sible new alternatives of purifying liquids as well as dis¬ posing of flushing fluids.
These objects are achieved according to the present inven¬ tion by carrying out a method of the type described above mainly according to what is stated in the characterizing clause of patent claim 1. The objects are also achieved
by means of a device according to the first device claim.
Additional characterizing features and advantages of the present invention are stated in the following description, reference being made to the accompanying drawings, which illustrate a not limiting embodiment:
Fig. 1 shows, in a partly schematic way in a vertical sec¬ tion, a device for liquid filtration according to the in¬ vention; and
Fig. 2 shows the same device in a perspective view, ob¬ liquely from above and with a partial sectioning.
A liquid filtration device 1 according to the present in¬ vention is shown in the drawings in its entirety. Device 1 comprises a box-shaped housing 2, which also can be cylin¬ der-shaped. The housing has a bottom 3 and sides 4,5,6,7 and preferably also a lid 8.
A cylinder-shaped chamber 9 is positioned in the center of the housing and is fully open at the top and limited by bot¬ tom 3 below. Between chamber 9, which is enclosed by wall 10, and sides 4-7 e.g. four cells 11,12,13,14 are positioned, which have the same size and are separated from each other by vertical partitions 15,16,17,18 , which extend between the central area of the respective housing wall and the opposite part of wall 10. The latter and the partitions may reach the same level as or a slightly lower level than the upper limiting edge of the outer walls of the housing.
Chamber wall 10 as well as the partitions extend to bottom 3 and may be welded to it. However, cells 11-14 do not reach the bottom but are limited downwards by a perforated sheet or the like 19, which is in a plane-parallel posi¬ tion above the respective bottom sections, intermediate chambers 20,21,22 and 23 being enclosed. Each such inter¬ mediate chamber communicates with chamber 9 via an ope¬ ning 24,25,26, and 27 respectively. An arbitrary filter
material 28 is placed on top of perforated sheet 19.
From e.g. a slightly higher intermediate level an outlet 29 for purified liquid extends horizontally from chamber 9 through one of the cells and the respective housing wall, on the exterior side of which the outlet is connected to a pipe line (not shown) designed to dispose of said liquid. An inlet 30 for polluted liquid is preferably positioned at a small distance above the outlet and extends through the same cell and then upwards immediately outside chamber wall 10 and into a distributing groove 31, which surrounds the upper end of wall 10 and comprises an outer wall 32 and a bottom 33. The groove follows the chamber outline and has openings 24-27 in its outer wall, which corresponds to ope¬ nings 34,35,36 and 37, which communicate with their respec¬ tive cells.
Along one of the outer walls of each cell a flushing groove 38 and 39 respectively extends, which may be a through groove for two adjacent cells and extend through an ope¬ ning 40 and 41 respectively in one of the housing walls outwards and be connected there to a pipe line (not shown) or the like, designed to dispose of the flushing liquid, which will flow outwards through said flushing grooves, the overflow inlet edge 42 and 43 respectively of which is positioned at a slightly lower level than the upper li¬ miting edge of chamber 9 and distributing groove 31 respec¬ tively and e.g. provided with cuts 44 according to Fig. 2.
A driving unit 46 with e.g. a base plate 47 and a vertical transmission tube 48 is on the bottom of chamber 9 in its central area rotatably mounted on a pivot 45, tube 48 at its bottom part being fastened to the base plate and bent outwards to a horizontally connecting part 49, which has a nozzle 50, designed to sealingly on the chamber side en¬ close one of openings 24-27. At its upper part tube 48 is bent inwards and ends in the central area of the chamber
in a turning device 51, which e.g. on top of lid 8 is con¬ nected to an electric motor 52.
At turning device 51 tube 48, e.g. via a valve 53, is connec¬ ted to a pump conduit 54, leading to a pump 55, mounted on the base plate and having suction openings 56 facing cham¬ ber 9.
From turning device 51 at the top a mainly horizontal arm 57 extends, and its end 58 projects into distributing groove 31 and supports there a sealing element 59, designed to sea- lingly cover one of openings 34-37. Sealing element 59 and nozzle 50 are designed to always be connected to the same cell and consequently they preferably are positioned in the same plane and on the same side of chamber 9.
Outlet 29 suitably starts from an overflow 60 in the upper part of the chamber on a level slightly below inlet 30.
Such a device functions in the following way: Polluted liquid flows through inlet 30 and into distribu¬ ting groove 31 and continues through either all of openings 24-27 or at least three of them and into the respective cells, in which, according to the right-hand part of Fig.l, the liquid flows downwards through filter 28 and perfora¬ ted sheet 19 and into intermediate chambers 20-23, to the extent openings 34-37 are opened up. From the intermediate chambers the purified liquid flows through opened up ope¬ nings 24-27 into chamber 9 and rises to its highest level, from which it flows past overflow 60 and into outlet 29. So far the process may work fine with or without the assis¬ tance of e.g. external pumps.
In case filter 28 in one of the cells needs to be cleaned, one proceeds according to what is shown in the left-hand part of Fig. 1. Driving unit 46 has via electric motor 52 been rotated to a position, in which nozzle 50 covers ope-
ning 24-27 respectively and at the same time connects the opening to tube 48. The liquid can no longer flow from the respective intermediate chamber to the main chamber. At the same time arm 57, with its end 58 and sealing element 59, shields upper opening 34-37 of the cell to groove 31, from which polluted liquid can no longer flow into the cell. However, polluted liquid continues all the time to flow through the inlet and into the rest of the cells. Pump 55 is now activated in order to suck purified liquid from the main chamber and feed it via pump conduit 54 and tube 48 into the intermediate chamber of the cell which is to be cleaned. From the intermediate chamber the fed purified liquid then rises upwards through the perforated sheet and upwards through filter 28, which is freed from at least a portion of the deposited impurities, which come along with the water flow in the cell upwards and via overflow inlet edge 42 and 43 respectively into groove 38 or 39 and out¬ wards through flushing outlet 61 or 62. After e.g. a cer¬ tain predetermined time the driving unit can be removed to either an inactive position or to the next cell in order to perform the same cleaning process in this cell. As an alternative the pump can empty a portion of the liquid in the main chamber or all of it, and in this way the water level in the main chamber will, by means of a floating bo¬ dy or the like, control the flushing process. Also, outlet 29 can be positioned at such a level that a continuous out- feed of purified liquid will be secured, in case this is desirable or an extra outlet or bypass conduit can be used. Thus, polluted liquid can be received in a continuous re¬ liable way by means of the described and shown process, which can be modified in an arbitrary way within the scope of protection set forth in the patent claims.
The present invention is not limited to the shown and des¬ cribed embodiments. Thus, it is feasible, with or without the use of a pump, to connect the intermediate chamber of the cell to be flushed instead of the main chamber to ano-
ther intermediate chamber, which can be done in a fairly simple way by means of a tube, which is diametricly dis¬ posed through the main chamber and is provided with a nozzle at each one of its ends and which constitutes an extension of connection 49. In this way it is possible to achieve a continuous outfeed of filtrate. Also, the area above the liquid level in the main chamber and the cells respec¬ tively can be connected to a temporary positive or nega¬ tive pressure, which can be used instead of using a pump.