Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
  • B01D24/002—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with multiple filtering elements in parallel connection
  • B01D24/005—Filters being divided into a plurality of cells or compartments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
  • B01D24/007—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with multiple filtering elements in series connection
  • B01D24/008—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with multiple filtering elements in series connection arranged concentrically or coaxially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
  • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
  • B01D24/10—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being held in a closed container
  • B01D24/18—Combined upward and downward filtration
  • B01D24/183—Combined upward and downward filtration the filtering material being supported by pervious surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
  • B01D24/46—Regenerating the filtering material in the filter
  • B01D24/4631—Counter-current flushing, e.g. by air

Definitions

• This invention relates to back flushable filters.
• filters comprising siliceous particles such as sand in which water is filtered by being caused to pass through the compacted sand particles and from time to time, a cleansing of the sand is effected by causing water to flow in a contra direction hence causing the sand to rise against an otherwise compacted condition but being held against excessive removal by gravitational forces, but such that detritus, which will normally catch within water flow more effectively than sand particles, will be carried away by the so called back flushing water flow.
• a first of these is that in order to effect an adequate back flushing, a sufficient water flow capacity must be provided to ensure that there is provided adequate flow to separate the detritus from the sand particles.
• the problems discussed can be at least significantly reduced by providing that the back f lushable filter has parts which are separately accessible, so that a part only can be selected for a back flushing action while other parts of the filter are accessible for a conventional filtering process.
• the invention can be said then to reside in a back f lushable filter comprising a body liquid filter means within the body adapted to provide for a filtering effect when liquid is directed in a first direction through the liquid filter means, and adapted to provide for a flushing effect when liquid is directed in an oppositive direction through the liquid filter means, the liquid filter means being divided into at least two parts in such a way that back flushing can be effected in at least one of the parts while filtering is being effected in the other of the parts and the valve means arranged to direct liquid flow through the liquid filter means, such that back flushing will be effected in at least one of the parts while filtering is being effected in the other of the parts.
• valve means adapted to drive said valve means, such that the valve means will be stepped through after a selected time from a first position to a- second positon whereby a back flushing effect is then effected in a further of the parts.
• the back flushable filter is characterised in that the body is of substantially cylindrical shape, with the parts of the filter being divided into chambers by divisions radially extending from its axial centre, each chamber including an upper access aperture and a lower access aperture, the valve means being adapted to direct through put of a selected chamber either in the case of back flushing, from the lower access aperture to the upper access aperture, or, in the case of effecting filtering from an upper access aperture through the chamber to a lower access aperture.
• a lower access aperture can be consituted by a plurality of apertures providing thereby a screen so that in the case that the filtering medium is sand or some fine particulate material, such will be retained from egress through any such aperture.
• FI6. 1 is a cross-sectional view with part cut away parts illustrating a filter constructed according to a first embodiment
• FIG. 2 is a perspective view of the filter of Fig. 1 , with however, part cut away showing three separate chambers two of which are in a conventional filtering mode and a third of which is a back flushing mode,
• FIG. 3 is a cross-sectional view of a second embodiment incorporating a stack of filter elements
• FIG. 4 is a view from above of the same emodiment as in Fig. 3 with a top cover part removed,
• FIG. 5 is in an enlargement of a part of the stack of filter elements illustrating the arrangement for providing the filtering effect
• FIG. 6 is a plan view of one of the elements constituted in the stack of filter parts In the second embodiment.
• a pressure sand filter which has a plurality of chambers 2 which are divided by dividers 3 which are fitted between an outer cylindrical container 4 and an inner upright conduit 5.
• Each of the chambers 2 is characterised by having a lower access aperture 6 and an upper access aperture 7.
• the lower access aperture is connected to be accessible to a lower part of the central conduit 5 at 8 through a tube 9 which includes a number of straining slots 10.
• straining slots 10 are selected to provide resistance to passage of siliceous particles e.g. sand during the filtering mode.
• the upper access aperture 7 is adapted to be variously connected by means of rotary valve 1 1 so that one of the upper access apertures 7 Is connected to conduit 12 which is directed to a disposal outlet while the remainder of the apertures 7 are connected through the upper part of the vertical conduit 5 at 13 whereby they are connected to inlet conduit 14 through which water can be directed which requires filtering.
• the lower part of the vertical conduit 5 at 8 is connected to the outlet conduit 15 which is directed to provide passage for water that has been filtered.
• rotary valve 1 1 The position of rotary valve 1 1 is adapted to be controlled by motor 16 operating which operates through shaft 17 whereby to effect rotation of gear 18 which operates against corresponding gear teeth on the outer side of the cover 1 1 at 19.
• the controls operating gear 16 are such that there is a timer and a stepping function such that the rotary valve 1 1 is stepped through from a position corresponding as shown in Fig. 1 with a first upper access aperture 7 to a next positon which is the next upper access aperture 7 in the adjacent vicinity so providing back flushing for a next adjacent chamber 2.
• each of the chambers 2 is loaded with sand so that the height of sand In a compacted state that is for conventional filtering will be approximately half the height of the respective chamber, and that the size of the sand particles is generally greater to the extent of the slots 10.
• the rotary valve 1 1 can be variously positioned so as to provide for a back flushing effect for each of the chambers.
• a substantially cylindrical container 20 which has within it a stack of filtering elements 21 which are each of annular shape as shown in Fig. 6 and each located one upon the other and held in this position by retaining ring 22 at the bottom and a top plate 23.
• the top cover plate 23 has a plurality of apertures 27 which are In turn aligned with the entry columns 28 within the stack 21.
• Fig. 5 illustrates the cross-sectional parts of the stack of filter elements.
• Each of the filter elements is comprised of wedge shape sections in cross-section as is shown at 29, each of the elements 21 having a substantially identical cross-sectional shape so that each of the elements provides an inclined surface as at 30 and at 31 each of which has the same angle of inclination providing a planar surface aligned to a meeting edge at 32 such that there is provided then a symetrically aligned passage way of decreasing width from an entry end at passage way 28 to an exit end at passage way 26.
• the narrowest gap at 33, the degree of inclination provided by the respective adjoining parts and the full length of the entry into the aperture is chosen so as to ensure in respect of the particles which will be required to be filtered, that there will be a trapping and compacting of such particles so that the particles themselves provide substantially the effective filtering.
• the container 20 further includes a rotary valve 35 the lower end of which at
• the position of the rotary valve 35 is governed by motor 37 which in turn drives through shaft 38 onto cog 39 which engages gears 40.
• the motor 37 1s once again governed so that it has two controlling functions a first a timing period function and a second a stepping function so that it is adapted to be driven for a period of time on a cyclic basis with a further given period between such actions such that the rotary valve 35 will accurately coincide with an appropriate segment at
• Each of the elements in the stack 21 Includes radial dividing elements 41 together with the cover plate 23 such that each passage way 27 and 26 are separated segment to segment so that coincidence of the rotary valve 35 with one of the said segments will allow separately
• a majority of the water can then be flushed out of outlet aperture in the direction of AA while a proportion of the water can be directed by reason of controlling the respective openness or closedness of the respective conduits through the segment being connected through the rotary valve 35.
• a disadvantage of the second embodiment is the fact that it relies upon some gathering of particulate materials upon a filtering function being returned but in practice as this is a very small proportion of the total amount of water which will actually be passing through the filter and further that it can be expected such detritus and particles will very quickly gather within the constraining gaps, this can provide filtered water with sufficient speed so as the small amount of detritus that might pass can be in most cases ignored.
• the size of conduits, the capacity for pumping, and the total size of the filtering element all can be based on significantly smaller pressures and flow rates because of the concept of the invention.
• the second embodiment article can be disassembled and completely cleansed if this is necessary by disassembling each of the filter elements from the stack, but it is expected that with careful selection of the gap inclinations and with the ability to provide high pressure back flushing with even the smallest of pumping capacity will make such action now very rare.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Filtration Of Liquid (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3771383

Family Applications (1)

Country Status (3)

Families Citing this family (4)

Citations (5)

Family Cites Families (7)

• 1986
  • 1986-11-21 EP EP19860906728 patent/EP0245384A4/de not_active Withdrawn
  • 1986-11-21 WO PCT/AU1986/000354 patent/WO1987003213A1/en not_active Ceased
  • 1986-11-21 AU AU67315/87A patent/AU593603B2/en not_active Ceased

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events