FILTER PRESS

Abstract

A filter press, including a housing, which receives a liquid to be filtered that contains particles to be separated off, and a pressing device arranged in the housing for pressing the liquid through a filter device, wherein the pressing device, which rotates about a vertical axis, has at least one cross-sectionally round pressing element which rotates about an axis of rotation situated at an angle to the vertical axis and which has an outer casing formed from an elastic material, by which the pressing element rolls on the filter device, wherein the filter device includes a filter and, upstream of the filter, a filter plate which has a plurality of apertures which are open toward the pressing element and each of which has a cross section reducing toward the filter.

Claims

1. A filter press, comprising a housing, which receives a liquid to be filtered that contains particles to be separated off, and a pressing device arranged in the housing for pressing the liquid through a filter device, wherein the pressing device, which rotates about a vertical axis, has at least one cross-sectionally round pressing element which rotates about an axis of rotation situated at an angle to the vertical axis and which has an outer casing formed from an elastic material, by means of which the pressing element rolls on the filter device, wherein the filter device comprises a filter means and, upstream of the filter means, a filter plate which has a plurality of apertures which are open toward the pressing element and each of which has a cross section reducing toward the filter means.

2. The filter press according to claim 1, wherein the apertures are round in cross section.

3. The filter press according to claim 2, wherein the apertures have an opening angle between 60°-120°, in particular between 75°-105° and preferably of 90°.

4. The filter press according to claim 2, wherein the apertures have a maximum diameter of 12 mm, in particular of 10 mm and preferably of 8 mm, and a minimum diameter of 8 mm, in particular of 6 mm and preferably of 5 mm.

5. The filter press according to claim 1, wherein the filter press has, downstream of the filter means, a second filter plate having second apertures aligned with the apertures of the first filter plate.

6. The filter press according to claim 5, wherein the cross section of the second apertures corresponds to the minimum cross section of the first apertures.

7. The filter press according to claim 1, wherein the filter means is or comprises a hole filter having a hole cross section of between 1-50 μm, in particular between 1-25 μm.

8. The filter press according to claim 7, wherein the hole filter is a perforated filter sheet or a perforated, preferably tear-resistant, plastics film.

9. The filter press according to claim 7, wherein a filter nonwoven is arranged directly downstream of the hole filter.

10. The filter press according to claim 1, wherein the outer casing is a covering composed of an elastomer, a thermoplastic elastomer or a rubber.

11. The filter press according to claim 1, wherein the outer casing is a mat which is fastened to a roller-shaped element body of the pressing element, or in that the outer casing is a coating.

12. The filter press according to claim 1, wherein a plurality of pressing elements are arranged so as to be offset in the circumferential direction and rotate jointly about the vertical axis.

13. The filter press according to claim 1, wherein the or each pressing element has a frustoconical shape.

14. The filter press according to claim 13, wherein the or each pressing element has an opening angle of 30°.

15. The filter press according to claim 1, wherein the filter device is frustoconical.

16. The filter press according to claim 15, wherein the filter device has an opening angle of 120°.

17. The filter press according to claim 1, wherein a collecting container for the pressed-through liquid is arranged downstream of the filter device.

18. The filter press according to claim 1, wherein the filter device has a central opening through which the vertical axis runs.

19. The filter press according to claim 17, wherein a collecting container for filter cakes consisting of compressed particles is arranged downstream of the opening of the filter device.

20. The filter press according to claim 1, wherein the or each press element is clamped against the filter device by way of a clamping device.

21. The filter press according to claim 19, wherein the or each clamping device is an actuating cylinder, in particular a hydraulic or pneumatic cylinder or a cylinder comprising a spring element.

22. The filter press according to claim 20, wherein the or each actuating cylinder is fastened by one end to a holder on which the pressing element is rotatably mounted and by the other end to a holder coupled to the vertical axis.

23. The filter press according to claim 1, wherein the vertical axis is formed by means of a shaft which is mounted so as to be rotatable by way of bearing elements and which is coupled to a drive motor and to which the pressing element(s) is/are coupled.

24. The filter press according to claim 22, wherein the shaft has its upper end running out of the housing and is coupled outside the housing to the drive motor, and/or in that the shaft has its lower end running into the collecting container and is rotationally mounted there.

25. The filter press according to claim 1, wherein a filling level-monitoring device, in particular a riser, is provided on or in a housing region above the filter device.

26. The filter press according to claim 17, wherein a liquid level-monitoring device, in particular a riser, is provided on or in the collecting container which receives the purified liquid.

27. The filter press according to claim 19, wherein a filling level-monitoring device is provided on or in the collecting container which receives the filter cakes.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0030] In the drawing:

[0031] FIG. 1 shows a perspective view of the filter press according to the invention,

[0032] FIG. 2 shows a longitudinal section view of the filter press from FIG. 1,

[0033] FIG. 3 shows an enlarged partial view with illustration of the pressing elements together with tensioning devices and filter device,

[0034] FIG. 4 shows an enlarged partial view for illustrating the angular relationships,

[0035] FIG. 5 shows a basic illustration to explain the operating principle of the filter press, and

[0036] FIG. 6 shows an exploded view of a filter device.

DETAILED DESCRIPTION OF THE INVENTION

[0037] FIG. 1 shows a cut-open perspective view of a filter press 1 according to the invention, comprising a housing 2, in which there are arranged a filter device 3 and also a pressing device 4 comprising, in the example shown, three pressing elements 5. The upper region of the housing 2 is shown to be open here. In this region, liquid, preferably water, laden with particles to be filtered off, is fed in via an inflow 6. The housing 2 is closed to the top by way of a cover 7 on which there is seated a drive motor 8 which drives a shaft 10 which forms a vertical axis 9 and to which the pressing elements 5 are connected. The pressing elements 5 roll on the filter device 3 and press the water through the filter device 3, whereas a large fraction of the particles remain suspended in the filter device 3. The cleaned water collects in a collecting container 11; see also FIG. 2, which collecting container 11 is configured as an annular space and is arranged downstream of the filter device 3. The cleaned water can be drawn off via an outflow 12.

[0038] Furthermore, the housing interior has provided therein a collecting container 13 which is arranged downstream of a central opening 14 of the filter device 3. In this collecting container 13 are collected pressed-out filter cakes which, on the one hand, are formed in the filter device 3 by the pressing elements 5 rolling over the filter device, but, on the other hand, are sucked out again from the apertures of the filter device 3 by way of said pressing elements, with the result that they can collect, while floating in the liquid, in the collecting container 13.

[0039] As FIG. 2 shows, the filter device 3 has a frustoconical shape or funnel shape. It is bolted on the housing via an annular flange 15 and is seated centrally on the collecting container 13. It can be seen that the pressing elements 5, of which three are provided here, which are arranged equidistantly around the circumference of the shaft 10, are also configured to be frustoconical, with the result that they lie on the filter device 3. Each pressing element 5 comprises a hollow element body 16 to the outer side of which there is applied an outer casing (not shown in further detail in FIGS. 1 and 2) which is composed of an elastic material and which will be described below.

[0040] In order to clamp the pressing elements 5 against the filter device 3, each pressing element 5 is preloaded against the filter device by a clamping device 17.

[0041] FIG. 3 is an enlarged detail view showing the region of the pressing elements 5 and of the filter device 3. There is shown, on the one hand, the filter device 3, which will be described in detail below, and also, in detail, a pressing element 5, with the element body 16, to which the already described elastic outer casing 18 is applied. This outer casing 18 is, for example, a mat composed of an elastic material such as an elastomer or the like, which mat is adhesively bonded to the element body 16 and is welded at the butting ends, resulting in an encircling, closed outer casing 18. The pressing element 5 is rotationally mounted via two bearing elements 19, here ball bearings, on a shaft 20 which is fastened to a holder 21. This, as it were clamp-like, holder 21 has its lower end coupled to a bearing element 23, which is connected to the shaft 10, so as to be pivotable via a bearing portion 22. Furthermore, the holder 21 is pivotably connected to the end 25 of a clamping device 17 via a further bearing element 24, with the clamping device 17 being coupled and pivotably connected by the other end 26 likewise to a corresponding holder 27 which in turn is connected to the shaft 10. This achieves a situation in which the corresponding pivoting connections allow a relative movement of the pressing element 5 such that it can be pressed firmly against the filter device 3 with deformation of the outer casing 18.

[0042] The or each clamping device 17 is an actuating cylinder 28, for example a hydraulic or pneumatic cylinder or a cylinder comprising a spring element or the like. In each case, this actuating cylinder 28, which can be varied in its length via an adjusting device 29 such that the contact pressure can be varied, makes it possible for each clamping device 5 to be correspondingly pressed against the filter device 3.

[0043] The holder 27 is, as described, likewise connected to the shaft 10. The shaft 10 is rotationally mounted in this region via a bearing block 30 and a bearing element 31 on a holder 32 which is fastened to a metal carrier sheet 33 which for its part is again fixed, on the housing inner side, via corresponding legs 34.

[0044] From there, the shaft 10; see FIG. 2, extends further and runs through the cover 7 of the housing 2, where it is connected to the drive motor 8 via a connecting element 35 so as to be constrained to rotate therewith, with the result that the shaft 10, and with it the pressing elements 5, can be rotated about the vertical axis 9.

[0045] At the other end, the shaft 10 runs through the opening 14 into the collecting container 13 and is received there in a corresponding bearing block 36 and rotationally mounted there and corresponding downwardly supported.

[0046] During operation, the drive motor 8 thus turns the shaft 10, with the result that the pressing elements 5 clamped against the filter device 3 by way of the clamping device 17 rotate about the vertical axis 9. At the same time, they roll on the filter device 3 by way of their elastic outer casing 18. That is to say that each pressing element rotates about two axes, namely, on the one hand, about the vertical axis 9 and, on the other hand, about the axis 20. Here, the elastic outer casing 18 rolls on the filter device 3 and, as described, presses a specific amount of liquid laden with dirt particles into the corresponding apertures of the filter device 3, where compression occurs on account of the elastic outer casing 18 being pressed in, with the result that, on the one hand, the water is pressed through the filter device 3 and is caught in the collecting container 11, whereas at the same time a filter cake is formed in each aperture and is subsequently sucked out again.

[0047] FIG. 4 is an enlarged partial view showing the angular geometry which the individual elements take with respect to one another. There is shown, on the one hand, the filter device 3 and, on the other hand, a pressing element 5, and also the vertical axis 9 in the form of the shaft 10. The filter device 3, which, as described, is configured to be funnel-shaped, has an angle α of 60° to the vertical axis 9, that is to say that the funnel-shaped filter device 3 has an opening angle of 120°.

[0048] The axis 20 about which each pressing element 5 rotates has an angle β of 45° to the vertical axis 9.

[0049] The pressing element 5 has the outer surface thereof of the element body 16, with said surface being situated closely to the vertical axis 9, at an angle γ of 30° to the vertical axis 9. Since the opposite side of the element body 16 runs parallel to the filter device 3, the side at that location is accordingly at an angle of likewise 60° to the vertical axis 9, just like the filter device 3. This results in an opening angle δ of the frustoconical element body 16 of 30°.

[0050] The fact that the filter device 3 and the adjacent side of the element body 16 are each at the same angle of 60° to the vertical axis 9 means that the elastic outer casing 18 situated therebetween is compressed virtually all over to the same degree over the entire bearing length.

[0051] FIG. 5 shows, in the form of a basic illustration, the pressing-out operation. What is shown here by way of example is only the elastic outer casing 18 of a pressing element 5 along with the filter device 3. This filter device 3 consists of; see FIG. 6, a first filter plate 37 which has a multiplicity of apertures 38 which are round in cross section, that is to say are configured as conical bores. In the example shown, the opening angle c is 90°. The largest diameter d1 at the side of the filter plate 37 facing toward the elastic outer casing 18 is preferably 8 mm, resulting in a cross-sectional area of about 50.2 mm.sup.2. At the opposite side, the minimum diameter d2 of the aperture 38 is preferably 5 mm, resulting in an opening cross section of about 19.6 mm.sup.2.

[0052] Directly downstream of the filter plate 37, that is to say bearing against it, there is a filter means 39 comprising a hole filter 40 in the form of a perforated metal filter sheet 41 or of a, preferably tear-resistant, perforated plastics film or hole plastics membrane. The metal filter sheet 41 has a multiplicity of holes, which have a diameter of 1-50 μm, preferably of between 1-25 μm. In other words, this hole filter 40 allows passage therethrough of only particles which are small than the hole cross section, meaning therefore that only extremely small particles can still get through the filter device 3, with all other particles being retained by the hole filter 40.

[0053] The filter means 39 further comprises a filter nonwoven 42 which serves to distribute, in the filter nonwoven plane, the water pressed through the hole filter. However, apart from the distribution of the water, the filter nonwoven also serves to provide a certain manner of sealing toward the hole filter 40 so that a certain counterpressure can be built up from this side, with the result that there is formed, within the aperture 38, a sufficiently high pressing pressure which, on the one hand, presses the water through the hole filter 40 and through the filter nonwoven 42 and which, on the other hand, firmly compresses the particles 46 to form the filter cake 48.

[0054] Downstream of the filter nonwoven 42 there is, finally, a second filter plate 43 which likewise has a multiplicity of apertures 44, which are aligned with the apertures 38 of the first filter plate 37. The apertures 44 have a diameter d3 which preferably corresponds to the diameter d2, that is to say is preferably likewise 5 mm, therefore likewise providing an opening cross section of about 19.6 mm.sup.2. The apertures 44 are no smaller in diameter than the minimum diameter of the apertures 38, but they can, where appropriate, also be somewhat larger. In each case, the water pressed through the hole filter 40, after it has also passed through the filter nonwoven 42 or has been distributed over the latter, can then flow off through the apertures 44 into the collecting space 11.

[0055] The function of the filter-pressing operation is illustrated in detail in FIG. 5. As described, the elastic outer casing 18, as illustrated by the arrow P1, presses under preloading onto the upper side 45 of the filter device 3. As is illustrated by the arrow P2, the pressing element 5 or the outer casing 18 rotates, on the one hand, about the shaft 20 and, on the other hand, about the vertical axis 9, with the result that it also moves around the latter, as illustrated by the arrow P3. It thus rolls on the upper side 45. Here, it is forced to roll over the apertures 38. While rolling over in such a way, what happens is that, on the one hand, as shown by the arrows P4, liquid including the particles 46 is pressed into a progressively rolled-over and thereby closed aperture 38. At the same time, however, the rolling-over action also causes a sufficiently high pressure to be exerted on the liquid situated in the aperture 38, not least since the elastic outer casing 18 presses slightly into the aperture 38. This results, on the one hand, in the liquid being pressed at high pressure against the hole filter 40 and being pressed through its holes into the filter nonwoven 42, whereafter the liquid flows off via the aperture 44. The liquid 47 is illustrated by way of the droplet symbols, with the arrows P5 showing the dripping action. At the same time, however, the particles 46 are retained by the hole filter 40 insofar as they are larger than the corresponding hole diameters. That is to say that a filter cake 48 consisting of firmly compressed particles 46 results in the conically tapering aperture 38.

[0056] Once the outer casing 18 then rolls further away, it rolls from the aperture 38, causing the latter to open continuously. What occurs here is that the individual filter cakes 48, which adhere somewhat to the outer casing 18, are concomitantly pulled out or sucked out of the aperture 38, since, upon opening of the outer casing 18 and rolling thereof, the outer casing material relaxes somewhat again. There thus occurs a certain suction effect, that is to say the formation of a negative pressure, with the result that the filter cakes 48 are sucked out. In other words, this results in self-cleaning of the filter device 3 since, on the one hand, the particles 46 are pressed into the apertures and strongly pressed to form the filter cakes 48, but, on the other hand, the individual apertures 38 are also automatically emptied again by virtue of the filter cakes 48 being pulled out or sucked out.

[0057] The rotating pressing elements 5 carry along the respectively adhering filter cakes 48, with the latter then being detached from the outer casing 18 and floating in the contaminated liquid situated in the upper container region. They sink downward in this region and pass either directly into the opening 14 or slide along the filter device 3 running conically toward the opening 14 into the opening 14 and, via the latter, into the collecting container 13. They can be drawn off therefrom as required, for which purpose either the collecting container 13 is opened, with this being associated with drainage of the dirty water also arising in the collecting container 13, or they can, preferably, also be extracted by suction via a corresponding suction-extraction nozzle 49, with the result that there is no need for the continuous filter process to be interrupted, not even for the removal of the filtered-off particles or filter cakes.

[0058] The elastic outer casing 18 is made of a sufficiently elastic material, preferably an elastomer or a rubber. It is preferably applied as a mat, but can also be applied as a coating. Its thickness is dimensioned in such a way that it can be sufficiently compressed, which, as explained with regard to FIG. 5, is required in order to generate the sufficient pressure in the respective filled aperture 38 such that the water 47 can be pressed out and at the same time the particles 46 can be compressed to form the filter cake 48, for which purpose the elastic outer casing 18 has to engage into the aperture 38 while molding itself into the shape thereof.

[0059] FIG. 1 also shows, finally, a filling level-monitoring device 50 which serves to be able to monitor the filling level of contaminated liquid in the upper region. Provided here is a transparent inspection glass 51, but it is also possible for an electronic filling level-monitoring device to be provided.

[0060] Although not illustrated in further detail, there further exists the possibility of also providing a filling level-monitoring device in the collecting container 11 in order to detect the filling level of cleaned water in this annular space. Additionally or alternatively, however, a filling level-monitoring device can also be present in the collecting container 13 in order to detect the filling level of introduced filter cakes 48 or else, where appropriate, loose particles 46 which may also form again as a result of the filter cakes 48 falling apart.

[0061] Depending on which filter device is provided, if it is electronic, a corresponding control of the associated peripheral devices can occur. In the case of an electronic liquid-monitoring device detecting the filling level of contaminated liquid, it is possible, for example, upon the filling level dropping to a minimum filling level, for a feed pump to be automatically activated such that the dirty water can be resupplied here via the inflow until a maximum filling level has been reached once again. In the case of an electronic filling level monitoring of the cleaned water, a pump, which draws off the liquid via the outflow 12, can be activated upon a maximum filling level being reached. Finally, in the case of an electronic filling level monitoring of the particle loading in the collecting container 13, a pump can be activated when a maximum filling level has been reached, with said pump allowing drawing-off of these particles 46 or filter cakes 48 together with a certain fraction of dirty water likewise situated in the collecting container 13.

[0062] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.