Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D37/00—Processes of filtration
  • B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
  • B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
  • B01D29/114—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for inward flow filtration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
  • B01D29/62—Regenerating the filter material in the filter
  • B01D29/66—Regenerating the filter material in the filter by flushing, e.g. counter-current air-bumps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
  • B01D29/62—Regenerating the filter material in the filter
  • B01D29/70—Regenerating the filter material in the filter by forces created by movement of the filter element
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
  • B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
  • B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection

Definitions

• the invention relates to a method for cleaning filter cartridges in precoat filters for liquids, wherein a filter cake located on the outside of the filter cartridge, consisting of a layer of filter aid and a layer of dirt, is dried by a flow of dry air before each renewed connection / emm process on the filter cartridge and by mechanical movement the filter candle is removed from it.
• a filter aid for example diatomaceous earth
• the solid particles contained in the contaminated liquid are attached to this filter aid.
• the filter layer consisting of the filter aid has a significantly smaller pore size than the filter medium underneath.
• the differential pressure at the filter increases.
• the filter cake must be cleaned and then precoated again before the filtration can be continued.
• the filter cake can be cleaned by backwashing with liquid. To do this, the liquid flow is reversed;
• an air or gas cushion is used in the clean room of the filter housing to increase the backwash flow.
• a drain valve is opened, the expansion of the air or gas cushion creates a relatively high pressure surge, which leads to a brief, strong flow in the filter cartridges. This will loosen the filter cake and discharge it as sludge when the filter housing is emptied.
• the sludge obtained in this way still contains a relatively large proportion of liquid and must therefore be prepared and dried in a complex workflow. This happens, for example, in a separate sludge filter.
• the filter cake is dried out. After reaching a predetermined differential pressure on the filter, compressed air or compressed gas is passed into the dirty space of the filter housing so that the liquid contained therein is pressed out. When the air or gas continues to be supplied, the filter cake is tapped on the filter candles and then thrown off by a mechanical movement of the filter candle.
• the mechanical movement of the filter candle takes place in a known method (DE-PS 28 28 976) by a vibrating drive which shakes the separating v / and in the filter housing so strongly that the filter cake falls off the filter candles. The design effort required for this is high; In addition, the filter cartridges are heavily stressed by the acceleration forces that occur.
• a support body carrying the filter sock of the filter candle is connected to a push element and can be moved in the longitudinal direction of the candle in order to blow off the filter cake located on the filter sock.
• the object of the invention is therefore to provide a method of the type mentioned, which makes it possible to completely clean the filter candle from all residues of the filter cake without having to accept the disadvantages associated with wet cleaning of the discharge of wet sludge.
• This object is achieved in that the filter candle is backwashed at least after several operating cycles comprising a precoating process, a filtering process and a cleaning process by a flushing flow directed in the opposite direction to the filter flow direction, before a new one. Precoating process takes place.
• the invention also relates to a device for carrying out the method according to the invention.
• a device for carrying out the method according to the invention Starting from a known filter device with at least one filter candle, which is arranged on a through-hole of a partition wall, which divides a filter housing of a precoat filter into a clean room and a dirt chamber containing the filter candle, a dirt tank being connected to the dirt chamber via a filter pump and a valve, and a line to the clean room via a valve leads to a clean tank and a compressed air supply line is connected to the dirty room via a valve is the device according to the invention characterized in that a further compressed air supply line is connected to the clean room of the filter housing via a valve.
• the invention is based on one
• the drawing shows a simplified circuit diagram of a filter device for liquids.
• a closed filter housing 1 which is divided into a clean room 3 and a dirty room 4 by a separator 2, a plurality of filter candles are preferably arranged, of which only one filter candle 5 is shown in simplified form in the drawing.
• the filter candle 5 has a support body (not shown) in the form of a helical spring which carries a filter sock on its outside.
• the coil spring forms a hollow cylindrical, openwork support body with a profiled outer surface for the filter sock.
• the filter candle 5 is closed at its lower end; at its upper end, the filter candle 5 is connected to the clean room 3 by a bore in the separating valve 2.
• a compressed air cylinder 6 forms a cleaning drive for the filter candle 5; its in the filter housing 1 - 6 -
• the inserted push rod 7 is connected to the lower end of the support body of the filter candle 5 in order to move it in the longitudinal direction.
• a line 19 branching off the line 17 can be connected to the clean room 3 via a valve 20.
• a precoat funnel 21 into which a filter aid, for example diatomaceous earth, can be added by means of a metering device 22.
• a line 23 branches off from line 12 and leads into precoat 21 via a valve 24.
• the outlet of the precoat funnel 21 can be connected to the line 9 via a line 25 and a three-way valve 26.
• In the line 25 also opens an intake port 27 from the bottom of the dirt tank 8.
• the line 9 is connected to an intake port 28 coming from the Rei tank 14.
• a backwash line 29 leads via a valve 30 into the line 23 opening into the dirt tank 8.
• a line 31 leads via a valve 32 also in this line 23 and in the dirt tank 8.
• valves described can be controlled by a common controller for the operation of the precoat filter device described below.
• the filter pump 10, the cleaning drive 6, the metering device 22 and the cylinder 14 for the sludge discharge are also controlled.
• the filter housing 1 is filled from the clean tank 14 by the filter pump 10, v / o when the three-way valve 26 makes the connection to the intake manifold 28 and the valve 11 is open.
• the filter candles 5 are moved by the drive 6 in order to achieve a rinsing effect, so that any adhering residues of filter aids or dirt are removed.
• Filter aids are introduced into the precoat 21 by the metering device 22.
• the filter pump 10 conveys the liquid with filter aids from the connecting funnel 21 via the three-way valve 26 and the line 9 into the filter housing 1.
• the valve 24 is . is opened and the valve 13 is closed, so that the precoat flow in the circuit through the lines 12 and 23 reaches the priming 21 again.
• the other valves are closed.
• the liquid to be filtered is pumped out of the dirt tank 8 via the intake port 25, the three-way valve 26, the filter pump 10 and the valve 11 into the dirt space 4 of the filter housing 1.
• the liquid flows from the outside through the layer of filter aids deposited on the filter stocking of the filter candle 5 into the filter candle, the dirt particles being deposited on the outside of the layer of filter aids.
• the filtered liquid passes into the clean room 3 and from there through the line 12 and the opened valve 13 into the clean tank 14. The other valves are closed. The filtering process continues until a predetermined differential pressure is established between the dirty space 4 and the clean room 3 due to the increasing dirt deposition on the filter candle 5, so that cleaning of the filter candle 5 is necessary.
• the filter housing 1 Before the cleaning process, the filter housing 1 is emptied. Compressed air is blown into the filter housing 1 from the line 17 via the valve 18. The liquid portion, which is pressed under the effect of the compressed air injection through the filter candle 5, gets into the clean room 3 and from there via the line 12 and the valve 13 into the clean tank 14. The remaining liquid is through the line 29 and the Valve 30 pressed into the dirt tank 8. A liquid residue remaining in the clean room 3 also reaches the dirt tank 8 via the line 31 and the valve 32. During this " emptying process, the valves 11, 13, 20 and 24 are closed.
• the filter cake is then dried on the filter candle 5.
• compressed air is blown further into the dirt space 4 through the opened valve 18.
• Valves 30 and 32 are opened intermittently in order to remove liquid residues from the clean room 3 and the dirt chamber 4 in the dirt tank 8.
• the valve 13 or a valve (not shown) connected in parallel, which also opens into the clean tank 14, is opened.
• valve 18 When the filter cake located on the filter candle 5 is sufficiently dry, the valve 18 is closed and the valves 30 and 32 are opened in order to reduce the pressure in the filter housing 1.
• the filter cake By mechanical movement of the filter candle 5 by means of the cleaning drive 6, the filter cake is thrown off the filter candle 5 and discharged through the closure 15 into the container 16.
• the filter candle 5 is backwashed with liquid.
• the filter housing 1 is first filled from the clean tank 14 by means of the filter pump 10 with the valve 11 open.
• the valve 24 is open; the other valves are closed.
• the valve 20 is then opened.
• the compressed air blown into the clean room 3 from the line 17 presses the liquid out of the clean room 3 in the opposite direction to the filter flow through the filter candle 5. All residues of the filter cake still located on the outside of the filter candle 5 are rinsed off.
• the liquid flows in through line 9 open valve 11 through the standing filter pump 10 in the dirt tank 8.
• the three-way valve 26 is set so that the line 9 is connected to the intake port 27 and the intake port 28 is shut off.
• the valve 30 is opened so that a residual emptying of the dirt space 4 can take place via the line 29. All other valves are closed.
• the filter housing 1 is filled in the manner described at the beginning before a new operating cycle begins.

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

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (2)

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Citations (5)

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• 1987
  • 1987-07-06 DE DE19873722238 patent/DE3722238A1/de active Granted
• 1988
  • 1988-07-06 WO PCT/EP1988/000602 patent/WO1989000073A1/de active Application Filing

Patent Citations (5)

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