DE20013748U1 - Magnetic filter device - Google Patents

Description

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R. Ohlmann GmbH, plant and mechanical engineering

Am Mühlberg 20 D-91477 Markt Bibart

Description

Magnetic filter apparatus

The invention relates to a magnetic filter apparatus with a tube arrangement through which a flowable medium can flow, into which magnetic rods can be inserted for separating magnetizable particles from the medium, and with a head-side connecting device which connects the tube arrangement on one side and with a foot-side connecting device which connects the tube arrangement on the other side.

Such a filter device is described in DE 91 02 175 Ul. Such filter devices are made of steel, particularly stainless steel. The manufacture and creation of the necessary mechanical connections is correspondingly complex. Steel and even stainless steel have a residual magnetism that develops when the magnetic rods are pushed in and pulled out. This residual magnetism has the disadvantage that metallic particles stick to the walls of the filter device and are difficult to clean off.

The metallic particles can settle in the filter device in places that are difficult to access during cleaning, which can lead to corrosion on the steel walls over time. The corrosion products can be carried along by the medium flowing through and then contaminate the medium to be cleaned.

Magnetic filter devices are used, for example, in the ceramics industry and the food industry to remove ferromagnetic particles from the respective medium.

The object of the invention is to propose a filter apparatus of the type mentioned at the beginning, in which there is no residual magnetism hindering cleaning, and which is not subject to corrosion by metallic particles and is of cost-effective construction.

According to the invention, the above object is achieved in a filter apparatus of the type mentioned at the outset in that the pipe arrangement and the connecting devices consist of a non-metallic, non-magnetizable plastic and that the pipe arrangement is connected to the connecting devices by means of plastic adhesive connections or plastic welded connections.

When magnetic rods are inserted into the pipe arrangement, the metallic, ferromagnetic particles of the medium attach themselves to the pipe arrangement in the desired manner, whereby the particles are separated from the medium. For cleaning purposes, the magnetic rods are pulled out of the pipe arrangement. Ferromagnetic particles adhering to the pipe arrangement can be easily cleaned off, for example by a countercurrent of water, since there is no residual magnetism in the plastic pipe arrangement and the plastic distribution devices.

that could retain the particles.

If metallic particles have become mechanically trapped somewhere in the filter apparatus for flow-related reasons, they cannot - unlike with steel - lead to rust and corrosion of the pipe arrangement and/or the distribution devices, since the metallic particles do not show any electrochemical reaction with the plastic.

Since the plastics cannot rust, rusted particles are not introduced into the medium. On the other hand, if ferromagnetic particles attach themselves to the steel due to the residual magnetism, the steel can be expected to rust over time, destroying the steel body and carrying the rusted particles along with the medium, thereby contaminating it.

The adhesive joints and/or plastic welded joints intended for connecting the plastic pipe arrangement and the connecting devices, which are also made of plastic, can be created in a technically simple and inexpensive manner. Complex steel welding processes and seals are unnecessary.

Preferably, the pipe arrangement and the connecting devices are made of the same plastic. However, the pipe arrangement and the connecting devices can also be made of different plastics. PVC, PP, PVDP or PE are preferred plastics.

Since the pipe arrangement and the connecting devices are made of plastic, it is easy to use a clear or transparent plastic. This improves the separation properties and

Cleaning behavior of the metallic particles in the area of the pipe arrangement and the flow patterns can be seen and controlled from the outside.

In a preferred embodiment of the invention, the pipe arrangement consists of jacket pipes and inner pipes running in them, with the medium flowing between the jacket pipe and the inner pipe and the magnetic rods being insertable into the inner pipes. The connecting devices each form a first wall and a second wall, with a space for distributing or collecting the medium between the first wall and the second wall. The jacket pipes are attached to the first walls and the inner pipes are attached to the second walls in a media-tight manner by gluing or plastic welding.

Further advantageous embodiments of the invention emerge from the subclaims and the following description of embodiments. In the drawing:

Figure 1 shows a magnetic filter apparatus schematically in longitudinal section with extended magnetic rods,

Figure 2 is a detailed view of Zone II of Fig.l,

Figure 3 shows an alternative embodiment of the filter apparatus to Fig.l in a view corresponding to Fig.l,

Figure 4 is a detailed view of Zone IV of Fig.3,

Figure 5 shows another alternative embodiment of a filter apparatus in a view corresponding to Fig.l,

Figure 6 is a detailed view of zone VI of Figure 5, Figure 7 is another embodiment of a filter apparatus in

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a view corresponding to Fig.l,

Figure 8 is a detailed view of Zone VIII of Fig.7,

Figure 9 shows another embodiment of a filter apparatus in longitudinal section,

Figure 10 is a detailed view of zone X of Fig.9,

Figure 11 shows another embodiment of a filter apparatus in longitudinal section, along the line A-A according to Fig.12,

Figure 12 shows the embodiment according to Figure 11 in plan view, Figure 13 shows a section along the line B-B of Figure 11, Figure 14 shows a section along the line C-C of Figure 11 and

Figure 15 is a table of the plastics that can be used, for example, to construct the filter apparatus, with the weldable (s) and/or adhesive (k) plastics being marked with &khgr; in the relevant column.

A filter apparatus consists of a pipe arrangement 1 and a base-side connecting device 2 as well as a head-side connecting device 3. The connecting device 2 forms a first wall 4 and a second wall 5. There is a space 6 between the walls 4, 5.

Likewise, the head-side connecting device 3 forms a first wall 7 and a second wall 8. Between the walls 7 and 8 there is a space 9.

Chambers 6 and 9 are collection chambers or distribution chambers for the medium, depending on the flow direction of the medium.

The figures assume the flow direction S, with space 6 being the distribution space and space 9 being the collection space.

The pipe arrangement 1 has a plurality of jacket pipes 10. An inner pipe 11 runs in each jacket pipe 10. In Figures 1, 3, 5 only two jacket pipes 10 with inner pipes 11 are shown. In practice, several jacket pipes with inner pipes are provided distributed on a circle.

The jacket pipes 10, the inner pipes 11 and the connecting devices 2, 3, especially their walls 4, 5 and 7, 8, are made of a non-metallic, non-magnetizable plastic. Suitable plastics for this purpose include polyvinyl chloride (PVC), polypropylene (PP), polyvinylidene fluoride (PVDF) or polyethylene (PE), or the other plastics shown in the table in Figure 15. The plastics used can be welded and/or glued. Adhesive films can also be used for gluing. The parts can be made of the same or different plastics. The jacket pipes 10 are preferably made of a transparent plastic so that deposits of metallic, ferromagnetic particles on the inner pipe 11 can be observed.

The filter apparatus has 12 magnetic rods on a carrier, with each inner tube 11 being assigned a magnetic rod 13. The magnetic rods 13 are held on the carrier 12 by means of fastening means, for example screws 14. By means of the carrier 12, the magnetic rods 13 can be inserted into the inner tubes 11 in the direction Z. In Figures 1, 3, 5, the magnetic rods 13 are shown in their extended position from the inner tubes 11. The jacket tubes 10 and the inner tubes 11 can be made of transparent, translucent plastic in order to clearly show the inserted position of the magnetic rods 13 and the

to be able to check the separated particles from the outside.

The walls 4,5,7,8 can also be made of transparent plastic in order to control the conditions in the rooms 6,9.

Preferably, the jacket pipes 10, the inner pipes 11 and the walls 4,5,7,8 are made of the same plastic.

The first walls 4,7 have holes 15 into which the jacket pipes 10 are inserted. The annular spaces 16 carrying the medium between the jacket pipes 10 and the inner pipes 11 open into spaces 6,9.

The second walls 5, 8 have holes 17 into which the inner tubes 11 are inserted. The inner tubes 11 are open both at the head-side connection device 3 for inserting the magnetic rods 13 and at the foot-side connection device 2 in order to avoid air pressure problems when the magnetic rods 13 move. The magnetic rods 13 can therefore be pushed into and pulled out of the inner tubes 11 despite the narrow gap without - in contrast to an inner tube 11 closed at the foot - an overpressure being created in the inner tube 11 when the magnetic rods 13 are pushed into the inner tubes 11 and a negative pressure being created in the inner tube 11 when the magnetic rods 13 are pulled out of the inner tubes 11.

The jacket pipes 10 are inserted flush into the holes 15 and are plastic-welded therein, for example by gluing, thermal action or by ultrasonic welding or high-frequency welding, whereby they are mechanically firmly and medium-tightly connected to the connecting devices 2, 3. Another plastic welding process can also be used to produce these connections.

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The inner tubes 11 can be inserted flush into the bores 17 of the second walls 5,8 and fixed therein just as firmly and tightly as the jacket tubes 10 in the first walls 4,7.

In Figures 2, 4, 6, 8, the annular surfaces at which the jacket pipes 10 are connected to the first wall 7 are designated by 18. Accordingly, in Figures 2, 4, 6, the cylindrical surfaces at which the inner pipes 11 are welded or glued to the second walls 8 are designated by 19.

In the embodiment according to Figure 1, the connecting devices 2, 3 each consist of one-piece plastic parts, with each of the spaces 6, 9 being formed by several radial holes 20. The holes 20 are set from the outer circumference of the connecting devices 2, 3 and then closed on the outside by means of plugs 21 made of plastic, with the plugs 21 being fixed by a plastic adhesive or plastic welded connection 22.

In the embodiment according to Figure 1, the two connecting devices 2, 3 are identically shaped parts, which simplifies production. A flange 23, 24 is arranged in the middle of the second wall 5, 8, which opens into a central bore 25, 26 of the second wall 5 or 8. The medium is supplied at the flange 23. A pipe 27 is arranged at the flange 24, which carries the medium away.

The radial bores 20 of the chamber 6 distribute the medium to the jacket pipes 10. The radial bores 20 of the chamber 9 guide the medium into the central bore 26.

In order to improve the distribution of the medium into the radial bores 20 of the base-side connecting device 2, a

Distributor cone 28 is arranged, which is fixed, for example, by means of a screw 29. In order to improve the introduction of the medium into the central bore 26, a further distributor cone 30 is arranged in the space formed by the radial bores 20, which is fastened to the first wall 7 with a further screw 31.

In the embodiment according to Figures 3, 4, the first walls 4,7 and the second walls 5,8 are each separate disc-shaped components. The walls 4,5 and 7,8 are each connected to outer sleeves 32,33 made of plastic to form the spaces 6,9, whereby the outer sleeves 32,33 are mechanically firmly and liquid-tightly connected to the end faces of the walls 4,5,7,8 by plastic adhesive or welded connections 34.

In the embodiment according to Figures 3, 4, the flange 23 of the foot-side connecting device 2 is arranged radially on the outside of the outer sleeve 32. The flange 24 is provided as in Figure 1.

In the embodiment according to Figures 5 and 6, as in the embodiment according to Figures 3 and 4, the walls 4, 5 are each individual disc-shaped components and are glued or plastic-welded by means of outer sleeves 32, 33. The flange 23 is provided on the base-side connecting device 2 as in the embodiment according to Figure 1. On the head-side connecting device 3, a flange 35 is arranged radially on the outer sleeve 33.

Distributor cones 28 and 30 are also provided in a suitable manner in the embodiments according to Figures 3 to 14.

In the embodiments according to Figures 3 to 8, the components forming the first walls 4,7

be designed identically. Accordingly, the components forming the second walls 5,8 can also be designed identically.

In the embodiment according to Figures 7, 8, the inner tubes 11 end within the holes 17 of the wall 8. In the remaining length of the hole 17, a further plastic pipe section 36 is inserted in alignment and flush with the respective inner tube 11. The pipe section 36 projects beyond the wall 8 and thereby extends the guide of the magnetic rods 13 so that they can be pulled out further for cleaning purposes than in the previously described embodiments. The plastic pipe sections 36 are firmly and tightly secured in the wall 8 by gluing or welding, just like the inner tubes 11. The pipe sections 36 can have a smaller inner diameter than the adjoining inner tubes 11, which ensures that the magnetic rods 13 are guided closely without jamming when moved.

In the embodiment according to Figures 7 and 8, instead of the outer sleeves 32, 33 of Figures 3 to 6, ring parts 37 made of plastic are provided, which connect the first wall 4 or 7 with the second wall 5, 8. The corresponding adhesive surfaces or welding surfaces are designated 38, 39 or 40, 41 (see Figure 8). In the embodiment according to Figures 7, 8, a circular bond is thus formed between the first walls 4 or 7 and the second walls 5 or 8, whereas in the embodiments according to Figures 3 to 6, a connection is made via the cylindrical outer sleeves 32, 33.

In the embodiment according to Figures 9 and 10, the inner tubes 11 are omitted. The magnetic rods 13 extend directly into the jacket tubes 10 through which the medium to be cleaned flows. Instead of the

A removable cover 42 is provided for the connection device 3 to the fixed wall 8, which is detachably secured to an inner flange ring 46 made of plastic by means of screws 43. The inner flange ring 46 is secured in the plastic outer sleeve 33 by gluing or welding. A sealing ring 44 is provided for media-tight sealing in the area of the screws 14. An O-ring 45 is provided for media-tight sealing between the inner flange ring and the cover 42.

Various other design variants are shown in Figures 11 to 14. A disk 47 is arranged between the wall and the wall 5 and a disk 48 is arranged between the wall 7 and the wall 8. Both disks 47, 48 consist of one of the plastics mentioned and are welded to the walls 4, 5 and 7, 8 or, if necessary, glued with adhesive films. The disks 47, 48 form channels 49 (Fig. 4) and 50, 51 (Fig. 13) which form the spaces 6, 9 and correspond to the radial holes 20 in Figure 1. The channels merge into cylindrical openings 52, 53 (Fig. 14) and 54 (Fig. 13) in the disks 47 and 48, respectively. The channels run in a star shape from the area of the central openings 25, 26 to the openings. The channels and the openings are produced, for example, using a water jet cutting process. The walls 4,5,7,8 can be produced in the same way. On the prefabricated discs 47,48, the channels and the openings are open on both sides of the discs.

The openings 52, 53 and 54 merge into the annular spaces 16 carrying the medium.

The channels open tangentially or spirally, i.e. on a spiral curve, into the corresponding opening. This imparts a rotational component to the flow of the medium to be filtered. The path of the flow through the annular spaces is thus extended, which

increases the probability that the ferromagnetic particles are retained.

On the other hand, the tangential or spiral opening increases the flow speed of the cleaning liquid, such as water, that is passed through to clean the deposited particles. This improves the cleaning effect. In Figure 13, channels 50 are shown as tangentially opening and channels 51 as spirally opening. Usually, all channels on one and the same disk are designed either tangentially or spirally opening. The spiral opening improves the turbulence of the flow compared to the tangential opening. However, with the spiral opening, corners can form adjacent to it in which particles of the suspension, i.e. the medium, other than magnetizable particles, can collect, which can be undesirable in certain cases.

In the embodiment according to Figures 11 to 14, a further measure for improving the flow conditions is shown. Reduction pieces 55 and 56,57 are provided, which reduce the flow cross-section from the space 6, or the openings 52,53,54, to the annular space 16. The reduction pieces 55,56,57 consist of one of the plastics mentioned and are on the one hand tightly fixed in the holes 15 by gluing or plastic welding and on the other hand are connected to the jacket pipes 10 in the same way.

In Figure 11, on the left, a flow cross-section reduction with only one reduction piece is shown and on the right, a flow cross-section reduction with a group of two reduction pieces 56, 57. The latter has a stronger and more distributed cross-section reduction than when using

only one reduction piece. For one and the same apparatus, either one or the other option is preferably selected for all jacket pipes 10.

Without the cross-section reduction by the reduction pieces, the separated particles would build up more in the annular space 16 in the area of the inlet, i.e. near the wall 4, than at the outlet, i.e. near the wall 7. This would cause the flow velocity to increase during operation in inverse proportion to the amount of ferritic particles separated. Due to the larger flow cross-section in the reduction pieces, the flow velocity there is lower than in the adjoining annular space 16. This results in a more even surface load of the inner pipe 11 with particles held back by the magnetic field. The particles are therefore distributed more evenly on the respective inner pipe 11. This advantageously extends the time between two necessary backwash cycles. This increases the service life and saves flushing medium.

During the course of the filter operation, so many particles will be deposited on the inner tubes 11 that cleaning will be necessary. For cleaning, the flow of the medium to be filtered, for example suspension, is switched off and the magnetic rods 13 in the inner tubes 11 are raised so that the particles are hardly affected by the magnetic fields any more. A flushing medium, for example water, is then passed through the filter apparatus via valves (not shown in detail), preferably against the flow direction S of the medium to be filtered. The flushing medium carries the deposited particles out of the space 9, the annular spaces 16 and the space 6.

In the embodiment according to Figure 9, 10, which is without

Inner tubes, the cover 42 can be lifted off together with the magnetic rods 13 for cleaning, after which the particles deposited on the magnetic rods 13 can be cleaned off and the chambers 9,6 can be flushed through.

The measures described individually in the individual embodiments can also be used in other described embodiments or further designs.

Claims (21)

1. Magnetic filter apparatus with a pipe arrangement through which a flowable medium can flow and into which magnetic rods can be inserted for separating magnetizable particles from the medium, and with a head-side connecting device which connects the pipe arrangement on one side and with a foot-side connecting device which connects the pipe arrangement on the other side, characterized in that the pipe arrangement ( 1 ) and the connecting devices ( 2 , 3 ) consist of a non-metallic, non-magnetizable plastic and that the pipe arrangement ( 1 ) is connected to the connecting devices ( 2 , 3 ) by means of plastic adhesive connections or plastic welded connections. 2. Magnetic filter apparatus according to claim 1, characterized in that the pipe arrangement ( 1 ) and the connecting devices ( 2 , 3 ) consist of the same plastic or of different plastics that can be welded and/or glued together. 3. Magnetic filter apparatus according to one of the preceding claims, characterized in that the pipe arrangement ( 1 ) and/or the connecting devices ( 2 , 3 ) consist of PVC, PP, PVDF or PE. 4. Magnetic filter apparatus according to one of the preceding claims, characterized in that at least the tube arrangement ( 1 ) consists of a transparent plastic. 5. Magnetic filter apparatus according to one of the preceding claims, characterized in that the pipe arrangement ( 1 ) is constructed from jacket pipes ( 10 ) and inner pipes ( 11 ) running in these, wherein the medium flows between the jacket pipe ( 10 ) and the inner pipe ( 11 ) and the magnetic rods ( 13 ) can be inserted into the inner pipes ( 11 ). 6. Magnetic filter apparatus according to one of the preceding claims, characterized in that the connecting device ( 2 , 3 ) has a first wall ( 4 , 7 ) and a second wall ( 5 , 8 ), wherein between the first wall ( 4 , 7 ) and the second wall ( 5 , 8 ) there is a space ( 6 , 9 ) for distributing or collecting the medium. 7. Magnetic filter apparatus according to claim 5 or 6, characterized in that the jacket tubes ( 10 ) are fastened to the first walls ( 4 , 7 ) and the inner tubes ( 11 ) are fastened to the second walls ( 5 , 8 ) in a media-tight manner by gluing or plastic welding. 8. Magnetic filter apparatus according to one of the preceding claims 5 to 7, characterized in that the jacket tubes ( 10 ) are open to the spaces ( 6 , 9 ). 9. Magnetic filter apparatus according to one of the preceding claims 6 to 8, characterized in that the distance between the first walls ( 4 , 7 ) is smaller than the distance between the second walls ( 5 , 8 ). 10. Magnetic filter apparatus according to one of the preceding claims 5 to 9, characterized in that the inner tubes ( 11 ) extend through the spaces ( 6 , 9 ). 11. Magnetic filter apparatus according to one of the preceding claims 5 to 10, characterized in that the inner tubes ( 11 ) are open on both sides. 12. Magnetic filter apparatus according to one of the preceding claims 6 to 11, characterized in that the first walls ( 4 , 7 ) and the second walls ( 5 , 8 ) each have bores ( 15 , 17 ) into which the jacket tubes ( 10 ) and the inner tubes ( 11 ) can each be inserted and glued and welded therein. 13. Magnetic filter apparatus according to one of the preceding claims 6 to 12, characterized in that the two walls ( 4 , 5 and 7 , 8 ) of the connecting devices ( 2 , 3 ) are formed in one piece, wherein the space ( 6 , 9 ) serving to guide the medium is formed by bores ( 20 ) which are closed on the outside by plugs ( 21 ). 14. Magnetic filter apparatus according to one of the preceding claims 6 to 12, characterized in that the two walls ( 4 , 5 and 7 , 8 ) of the respective connecting device ( 2 , 3 ) are separate components, the space ( 6 , 9 ) between them being formed by an outer sleeve ( 32 , 33 ) or an annular part ( 37 ) or a disk ( 47 , 48 ). 15. Magnetic filter apparatus according to claim 14, characterized in that the outer sleeve ( 32 , 33 ) or the ring part ( 37 ) or the disc ( 47 , 48 ) consists of plastic and is connected to the walls ( 4 , 5 ; 7 , 8 ) by a plastic adhesive connection or a plastic welded connection. 16. Magnetic filter apparatus according to one of the preceding claims, characterized in that the space ( 6 , 9 ) is connected to a pipeline carrying the medium by a flange ( 23 , 24 , 35 ) arranged on a second wall ( 5 , 8 ) or on the outer sleeve ( 32 , 33 ). 17. Magnetic filter apparatus according to one of the preceding claims 14 to 16, characterized in that the disc ( 47 , 48 ) forms channels ( 49 , 50 , 51 ) for guiding the medium. 18. Magnetic filter apparatus according to one of the preceding claims, characterized in that the bore ( 20 ) opens tangentially and the channels ( 49 , 50 , 51 ) open tangentially or spirally. 19. Magnetic filter apparatus according to one of the preceding claims, characterized in that reduction pieces ( 55 , 56 , 57 ) reduce the flow cross-section of the pipe arrangement in the flow direction (S) of the medium. 20. Magnetic filter apparatus according to one of the preceding claims 5 to 19, characterized in that the inner tubes ( 11 ) extend beyond the wall ( 8 ) by means of tube pieces ( 36 ). 21. Magnetic filter apparatus according to one of the preceding claims, characterized in that the one connecting device ( 3 ) has a removable cover ( 42 ) to which the magnetic rods ( 13 ) are fastened.