DE4217666A1 - Filter assembly - has candle-shaped filters on an intermittent rotating plate to increase the filter density - Google Patents

Abstract

The filter assembly, to separate solids from liquids, has a number of candle-shaped filters fitted to a rotary plate which is turned in steps, within a pressurised filter housing. The outlines (32,33) of the filters, arranged in order (1'-12'), converge towards the centre of the rotary plate. The filtrate take-off (9) is at the peak of the converging lines (32, 33) of the filter outlines. The converging edges (32,33) of the filter outlines are joined by a rounded curve, which partially surrounds the filtrate take-off tube (9). The other ends of the filter outline, away from the plate centre, are joined by a straight line completing the filter outline shape, or they are joined by a roof-shaped angle (34,35). A filter unit housing has an axial movement above the fluid level in the filter housing which, on rotation of the plate, releases a filter in its position (1'-12') and covers it on a further rotation of the plate. The cross section line of the filter unit housing is generally parallel to the cross section lines of the filter cross sections. The filter unit housing, in the direction of rotation, is after the station where the retained solids are removed, and the filter is repeatedly immersed in the fluid to be treated, after a filtering action to prepare the filter medium. The filter unit housing provides pre-coating of the filter medium by rinsing in a fluid pre-coating, through a fluid inlet and outlet switched into operation alternately. The fluid inlet ends in a wide-slit jet over the fibres, with a jet stream covering the filter lengths. The filter housing has a two-part cover with a concentric inner cover to carry a rotary bearing for the plate shaft and a suspension for the shaft control disc, and the shaft is secured at its lower end in a holder at the base of the housing. This gives an opening for the insertion and removal of the filters. The retained solids are removed at a compressed air lock, with a climbing conveyor in a pressurised encapsulation between the lock and filter housing, to carry the material to an ejection point over the lock. USE/ADVANTAGE - The filter assembly is a pressure filter for technical fluids, to separate solids from the liquid such as for treating process water with water cleaning. Through the filter shape, more filters can be fitted to the rotary plate, with simple removal of the retained solids and filter change while other filters are in use.

Description

The invention relates to a liquid filter according to the preamble of claim 1.

In particular, the invention relates to rivers liquid pressure filter, which u. a. for technical rivers liquids for separating a solid phase from the Liquid can be used. It can be the treatment of process water with the aim of Act water purification. The particularly in high filter performance required in such cases relies essentially on liquid pressure filters that the excess pressure in the filter housing Pressure drop in the filter cartridge increases so that the filter cake formed by the solid phase filtering liquid on the filter medium grows strongly as soon as the filter candle in question is flowed through from the outside to the inside.

The comparatively high filter performance of such and other liquid filter according to the invention is based also on continuous filtration. they it follows that the progressive switching turntable the removal of the filter cake allows while a variety of Filter candles continues to work, d. H. in the to fil and liquid in the filter housing dive out. Another advantage with fiction According to liquid pressure filters is that  the filter cake is comparatively dry, because the drying process is above the liquid kesssspiegel and until the removal of the Filter cake continues. That eases the rest Treatment of the filter cake essential. That's why are such filters also for very dirty ones Liquids with a filter that is difficult to drain cake suitable.

These and other advantages of the invention Liquid filters are based essentially on the spe Filtration process resulting from the Operation of the filter according to the invention results. Because the step-by-step turntable the filter candles one after the other to filter immersed liquid and through the liquid moving, they dip with a filter cake finally put filter cartridges back on and get into a dry sphere above the liquid mirror in the filter housing. With liquid pressure filters, the pressure drop initially remains in get these candles and press that way the residual liquid as filtrate from the filter cake. On the way to immersion in the liquid to be filtered becomes so dried filter cake from the surface of the Removed filter media from each filter cartridge. This can serve an airstop, the pressure drop in the Filter candle reverses and thereby the filter cake blows off.

Liquid pressure filters of this type are in themselves known (Zeitschrift Aufbereitungstechnik 27, 1986, SS. 387/395). The filter cartridges consist of usually from a variety of axial washers filter, mostly also in opposite directions  their circulation in the filter housing around the axis of the fil turn candles.

The disc shape of the filter cartridges is with these known designs chosen to be as possible to achieve a large filter area. That forces you basically round clear cross-section of the fil candle in which the filtrate is obtained. For removal of the filtrate serve processes in the candles, mei at least in the form of concentric tubes. To the Liquid on the entire circumference of the filter to remove candles, these must be switching the turntable around its axis of symmetry in turn be rotated. That has corresponding Required drives with the turntable drive must work together. The thereby he forced technical effort is ver equally large space requirement for the filter cartridges still enlarged. Because on the one hand it forces Disc shape of the filter surfaces a considerable Distance between the filter candles to the Fil to be able to blow off the cake completely, and others on the other hand, it is difficult to remove filter cake residue the gussets between the adjacent filters disks because of the outward converging Detach the edges of the pane completely.

Further problems can arise if the The filter cake is not as described above sprinkle off the filter medium of the filter cartridges gen leaves. The filter performance suffers considerably from this Lich. That depends in particular on the material Composition of the filter cake Solids from the liquid to be filtered. If this is on the filter cake medium develop significant adhesive forces, this can lead to  difficulties mentioned lead. For example ver cause greases or residues of hydraulic fluids corresponding disadvantages in solids.

In contrast, the invention takes a different path, whose basic idea is reproduced in claim 1 is. Other features of the invention are the subject of subclaims.

With the features of claim 1, the outline line of the cross section of the filter cartridges in such a way changed that from the circular cross section deviates; at the same time the filter cartridges become like this oriented that the outline of their cross section towards the center of rotation of the turntable converges; as soon as the filter candles replace therefore the filtrate runs down into the respective deduction. Since the filtrate drain also exzen trisch in the direction of the center of rotation of the rotation plates is arranged, is practical for the created a gradient throughout the filter cake the liquid in the filter candle towards the deepest of the filter candle cross section and thus leads into the drain as soon as the filter candles above half of the liquid level in the filter housing stand. The one in these filter cartridges Filtrate can thereby be practically completely subtract, which further increases the filter performance and the filter cake dries better.

Incidentally, it turned out surprisingly that the transition from the well-known disc shape of the Filter surface on the hollow prism training the filter surface, at least  but not significantly diminished. That is u. a. on the possibility of being a comparatively denser Arrangement of the filter candles on a pitch circle arrange the center of rotation of the turntable can and thereby the number of filter cartridges enlarge. The signs above are also omitted through the gusset design of the disc filter due to difficulties with complete removal of the filter cake.

The invention is therefore preferably implemented gene also with the features of claim 2. Die resulting approximate circle sectional shape of the filter candle cross section allowed an optimally tight arrangement of the filter candles the mentioned pitch circle around the center of rotation of the Turntable and also guaranteed by the Arrangement of the filtrate deduction a complete Removal of the filtrate from the filter candle.

With the features of claim 4, the cross sectional shape of the filter candles further specified. The roof-shaped slope provided therein works favorable to the withdrawal of the filtrate from the Filter candle out because it is draining the liquid favored. The one described in claim 3 The alternative, on the other hand, has the advantage of simplification form and through the geometrical as Secant to a pitch circle around the center of rotation appearing straight line of the candle cross section Advantage that the filter housing in the radial direction can be reduced.

The features of claim 5 can also be independently, d. H. regardless of the above described features of the filter cartridge according to the  Realize claims 1 to 4. Because of this is in the filter housing through the filter cartridge housing a closed space created; he can on different ways to improve the filter find effect. For example, in it the pressure of the sphere change more rationally, because the volume in the filter cartridge housing is essential is smaller than that in the filter housing. That can when the filter cake bursts off Compressed air blast low on energy consumption Act. In this context and also under the point of view of the space-saving arrangement of the Filter cartridge housings in the filter housing are the Features of claim 6 advantageous.

With the features of claim 7 is by Arrangement of the filter cartridge housing in the filter housing behind the station where the filter cake is deposited is blown, an action on the filter medium possible that start the new filtering process increases. The filter medium often consists of one Filter fabric, its effects on the stock parts of the filter cake after removing the filtered particles can be optimized. With the features of claim 8 is thereby Pre-coating possible. This will result in detention assets of the filter cake or contained therein special components on the filter medium greatly reduced that, as a result, the filter candle when immersed in the liquid completely dig is cleaned. Come with the pre-coating Substances and compounds into consideration that the particular ent persistent filter cake components ent are adapted accordingly. You make the filter medium repulsive against it. Have proven themselves in this connection diatomaceous earth, lignite dust  u. the like

Another way to optimize the Filtering process with the described filter candles Housing is given in claim 9. Here can be a multi-stage preparation of the filter medium for the subsequent filtration chen. E.g. each filter candle is rinsed before immersing in the liquid to be filtered to remove filter cake residue. If it the filtrate is clarified process water acts, but can also be used for backwashing filtrate another purified process water is used will. These rivers entering the filter candle liquid is contaminated with the filter cake residues and is therefore preferably withdrawn from the filter cartridge before being subjected to the pre-coating and then in the liquid to be filtered is diving.

In practice, this possibility is a reality and inevitably z. B. with the pre-coating verbin the.

With the features of claim 11, the Prepare the filter cartridge for a new one Accelerate filtration because then with the help of Wide jet nozzle the filter candle on their entire Length is processed accordingly.

Maintenance and repairs are essential ratur possibilities with such liquid fil tern. The features of claim 12 offer for this an advantageous solution. Since you see the wave of Stores turntables in the manner described there, can be removed after removing the case base or  

Pull the housing cover off the shaft with a twist plate and filter cartridges together from the filter remove the housing. On the other hand, the assembly offers opening in the filter housing base the possibility of Replace filter cartridges individually.

The details, other features and other advantages parts of the invention result from the following ing description of an embodiment based on the figures in the drawing; it shows

Fig. 1 is a schematic cross section through a fluid pressure filter, omitting all details not required for understanding the invention,

Fig. 2 shows a section along the line BB of Fig. 1 and

Fig. 3 is a section along the line AA in FIG. 1.

The generally designated 1 in Fig. 1 liquid pressure filter is provided according to the exemplary embodiment shown for the separation of a solid from a process water which forms the liquid to be filtered. In the hollow cylindrical filter housing 2 , a turntable 4 is rotatably mounted on a shaft 3 rotating in the direction of the arrow in FIG. 2. The shaft 3 can be switched in steps. On a pitch circle of the turntable 4 sit at regular intervals in Fig. 2 with the ordinal numbers 1 to 12-designated hollow prismatic filter candles. 5 The interior 6 of the filter housing 2 is under positive pressure. The lower part 7 of the filter housing is filled with the liquid to be filtered, the liquid speed level 8 is held at a predetermined height in the filter housing. Due to the gradual rotation of the shaft 3 , the filter cartridges with the atomic numbers 1 'to 12 ' move clockwise one after the other into the liquid 7 to be filtered and emerge from it again. In the exemplary embodiment, the filter candles with the ordinal numbers 10 to 2 are above the liquid level. The remaining filter cartridges are immersed in the liquid to be filtered. Each filter candle contains an axial drain pipe 9 , with which the filtrate is drawn off from the interior of the filter candle.

In the operating state shown in FIG. 2, filtrate is continuously withdrawn from the filter candles with the ordinal numbers 3 to 9 . The filter candle with the atomic number 10 is immersed in the liquid to be filtered. The removal of the filtrate is continued in it, as a result of which the filter cake is dried on the filter medium 10 . This drying process is continued in the following station, in which the filter candle with the atomic number 11 is located. The filter cake is only blown off in the next station, in which the filter candle with the atomic number 12 is located. For this purpose, a pneumatic overpressure is generated in the interior 11 of the filter candle 12 ' , through which the filter cake is blown off and applied to a conveyor belt 12 located underneath. The conveyor belt 12 leads the filter cake from the pressurized inner space of the filter housing 2 .

Above the liquid level 8 , a wide jet nozzle can be provided in the filter housing 2 in the direction of rotation after the filter cake rinsing station for rinsing the filter cake residues. After index rotation of the turntable 4 , the filter candle with the atomic number 2 'then gets under the wide jet nozzle. A backwashing liquid emerges from this, which rinses the non-blasted parts of the filter cake in front of the filter medium and takes them on their way into the liquid 7 to be filtered.

To one of the clock sequence of the turntable correspond to the arc angle, the filter cartridge with the atomic number 2 'sits in a filter cartridge housing 15 , which consists of an axially movably driven sleeve 16 , the end face directed into the pressure chamber 6 of the filter housing 2 is open and with a seal 17th seals on the inner wall 18 of the turntable 4 . The jacket of the sleeve 16 is guided through a recess corresponding to the outline of the sleeve in the housing wall 19 of the filter housing 2 to the outside. The recess has an annular seal 20 . The outer end of the sleeve 16 is provided with a bottom 21 . A drive 22 acts on it.

This consists of a preferably hydraulically driven piston in a double-acting working cylinder 24 . The piston rod 25 of the piston acts via a lever 26 directly on the bottom 21 of the sleeve, whereby the sleeve of the filter candle housing 15 depending on the cycle of the turntable 4 via a filter candle - in the exemplary embodiment, the filter candle marked with the ordinal number 2 '- slipped over or can be removed from the filter candle to the extent that the action of the backwash liquid exiting from the wide jet nozzle 14 is ensured on the filter fabric.

The bottom 21 of the sleeve 16 carries a connection for a tube 23 , which is provided with a shut-off device 27 , not shown, in front of the bottom 21 . Between the bottom 21 and the shut-off device 27 branches off a line. In this a further shut-off organ is installed.

In operation, the liquid emerging from two wide-jet nozzles 28 , 29 acts on the filter medium 10 of the filter candle in the filter candle housing 15 over a predetermined time during the standstill of the turntable. Here, the sleeve 16 is advanced so that the liquid acting on the filter candle (e.g. lignite dust mixed with water) does not get into the liquid to be filtered. Once this temporary process is complete, the z. B. removes filter cake residues from the filter candle through the branch line with the shut-off device open, the pre-coating takes place, for example, with the liquid described. This also happens during a turntable standstill over a predetermined period. The shut-off device is closed. As a result, the filter medium 10 is prepared so that normally adhering filter cake components easily detach from the filter medium as soon as the filter cake cleaning takes place at 11.

Regardless of the aforementioned features, the special shape of the filter candles with the ordinal numbers 1 to 12 can be realized in the elongated hollow form shown in FIG. 2. Here, the filter candle cross-section of the effective filter surface is the same in all cross-sections and is provided with an outline 30 which has converging paths in the direction of the center of rotation 31 of the turntable, which are identified by 32 and 33 in FIG. 1. The liquid drain from the filter candle with the help of the tubes 9 is located below the apex of the converging outline lines 32 , 33 . Since the filter candles with the atomic numbers 1 'to 12 ' are arranged on the turntable so that the apex of their outline sections 32 , 33 inside, ie on radii of the center of rotation 31 , the liquid runs within the immersed filter candles - in the embodiment of the filter candles the ordinal numbers 10 to 2 - with a downward slope to the exhaust pipes 9 .

At the apex, the outline sections 32 , 33 are connected to a curved, ie arcuate outline section 34 . On the opposite side, the converging outline section 32 , 33 can be connected with a roof-shaped, double slope in the manner of a hipped roof. Then there is also the possibility of optimally attaching the filter candles to the turntable 4 . This is done with three studs 35 to 37 . Two stud bolts 36 and 37 are then located under the bevels. The third stud is arranged next to the exhaust pipe 9 inside the filter candle.

As is apparent from the illustration of FIG. 1 also follows the contour 30 of the sleeve 15 is substantially the shape of the contour lines 32, 33, 38 of the filter cartridges and surrounding this with suffi chendem motion. As a result, a small interior space of the sleeve 16 is achieved for a given outline 30 of the filter candles. In the illustration of FIG. 1, a preferred embodiment of the invention is shown. In place of the slope, not shown, a straight section 38 of the cross section. Even in this case, however, circular segment-shaped cross-sections are created, which enables an optimal arrangement and number of filter cartridges with atomic numbers 1 'to 12 ' on a given pitch circle around the shaft of the rotary dialer.

The cylindrical filter housing 2 has a cover 40 on one end face. This is screwed to a flange 41 , the screws being arranged on a pitch circle around the shaft 3 of the turntable 4 . On a further inner pitch circle sits the screwing of a concentrically inner cover 42 , which contains the end bearing 43 of the shaft 3 and stud bolts 44 , which hold a non-rotatable control disk 45 and in which the shaft 3 runs. The free shaft end is mounted in a bearing sleeve 29 , which is rotatably attached to the inside of the housing base 46 . The housing base is screwed to a flange 47 of the cylindri's housing shell. Furthermore, the openings described are located in the housing base, in particular the opening 48 , through which the filter cake is removed from the filter housing 2 .

Through an opening (not shown) in the housing base 46 , the nuts 49 , 50 of the stud bolts 36 assigned to the housing base can be loosened and the filter candles can be removed from the turntable 4 . This enables simple assembly and disassembly of the filter cartridges.

If the turntable with the filter candles has to be replaced as a whole, this is possible in a simple manner, since after removing the housing base 46 and releasing the stud bolts 44, the shaft can be pulled off the cover.

The conveyor 12 used to remove the filter cake is encapsulated in a pressure-tight manner between the filter housing 2 and a compressed air lock 51 with mutually actuated flow valves 52 and 53 with a housing 54 . As a result, the total compressed air consumption is reduced. The discharge drum 55 , which is provided with a scraper 56 , is located in a housing attachment 57 , so that the filter cakes reach the lock 51 directly from above.

Claims (13)

1. Liquid filter with a plurality of filter cartridges arranged on a step-by-step turntable in a preferably pressurized filter housing in which the filter candles emerge one after the other from the liquid to be filtered, each time during the standstill of the turntable in several stations arranged above the liquid level Filtrate is discharged from the filter candles by a deduction arranged in the clear cross section of each filter candle before the filter cake is removed from the filter candles in at least one subsequent station, characterized in that the outline ( 35 , 33 , 51 ) of the cross section of the filter candles with the ordination numbers ( 1'-12 ' ) converges towards the center of rotation of the turntable ( 4 ), and that the filtrate discharge ( 9 ) is arranged at the apex of the converging sections ( 32 , 33 ) of the outline. 2. Liquid filter according to claim 1, characterized in that the converging part stretch ( 32 , 33 ) of the outline of the cross sections of the filter candles with the atomic numbers ( 1 '-12') each by an arc ( 33 a) are the verbun the filtrate discharge ( 9 ) formed as a tube is partially enveloped. 3. Liquid filter according to one of claims 1 or 2, characterized in that the ends of the converging sections ( 32 , 33 ) of the contour lines of the filter candle cross sections facing away from the center of rotation of the turntable ( 4 ) are connected to one another by a straight line ( 51 ). 4. Liquid filter according to one of claims 2 or 3, characterized in that the ends of the converging sections ( 32 , 33 ) of the contour lines of the filter candle cross sections facing away from the center of rotation of the turntable ( 4 ) are connected to one another by a roof-shaped bevel ( 34 , 35 ) . 5. Liquid filter in particular according to one of claims 1 to 4, characterized in that above the liquid level ( 8 ) in the filter housing ( 2 ) an axially movable filter candle housing ( 15 ) is provided, which in one position pay the filter candle with the order ( 1'-12 ' ) and thus the further rotation of the turntable ( 4 ) releases and in a further position encloses the filter candle with the ordinal numbers ( 1'-12' ). 6. Liquid filter according to claim 5, characterized in that the cross-sectional line of the filter candle housing ( 15 ) is substantially parallel to the cross-sectional lines of the filter candle cross-section. 7. Liquid filter according to one of claims 5 or 6, characterized in that the filter candle housing ( 15 ) in the direction of rotation after the Sta tion ( 11 ) in which the filter cake is blown off, is arranged and to prepare the filter medium of the enclosed filter candle with the Atomic numbers ( 1'-12 ' ) for a new filtering operation before repeated immersion in the liquid to be filtered. 8. Liquid filter according to one of claims 5 to 7, characterized in that the filter candle housing ( 2 ) is used for pre-coating of the filter medium. 9. Liquid filter according to claim 5, characterized in that the filter candle housing ( 15 ) for rinsing a liquid pre-coating on the filter candles with the atomic numbers ( 1 '-12') is used. 10. Liquid filter according to one of claims 8 or 9, characterized in that the filter candle housing ( 15 ) with a liquid outlet ( 28 ) and a liquid inlet ( 29 ) is provided, the outlet and inlet being sequential and mutually switchable. 11. Liquid filter according to one of claims 8 to 10, characterized in that the inlet ( 29 ) in the filter cartridge housing ( 15 ) ends at a wide jet nozzle ( 4 ) which above the enclosed filter cartridge with the atomic numbers ( 1 '- 12 ') is arranged and the nozzle jet extends substantially over the length of the filter candle with the atomic numbers ( 1 '- 12 '). 12. Liquid filter according to one of claims 1 to 11, characterized in that the cylindrical filter cartridge housing ( 2 ) has a two-part cover ( 40 ) with a concentrically inner cover ( 42 ) which the pivot bearing ( 43 ) of the shaft ( 3 ) the turntable ( 4 ) and the suspension ( 44 ) carries a control disc ( 45 ) of the shaft, which is supported with its free end in a removable filter housing base ( 46 ) which has an assembly opening for installing and removing the filter cartridges with the atomic numbers ( 1 '- 12 '). 13. Liquid filter according to one of claims 1 to 12, characterized in that for removal tion of the fil removed from the filter cartridges a compressed air lock is provided, whose job is between a lock and Filter housing encapsulated in a pressure-tight manner of those formed whose dropping is above the Lock is arranged.