LU86109A1 - Filter press with casing sub-divided into chambers - each contg. stout rigid filter fixed relative to its axis - Google Patents

Abstract

A filter press has an assembly of plates and casings defining filter chambers, a stout rigid filter in a fixed position relative to the axis of each chamber dividing it into compartments for suspension and filtrate, an inlet to each suspension compartment and an outlet from each filtrate compartment, and a system removing filter cake from the suspension compartments after their compression. A method of filtering is also claimed.

Description

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The present invention relates to a filtering device of the filter press type, in particular for the filtration of brewery wort, comprising plates and possibly assembled frames forming between them filter chambers, at least one inlet into each filter chamber for the introduction of the material to be filtered, filtration means separating in each filtering chamber a compartment of material to be filtered, a compartment for collecting the filtrate, at least one outlet for the filtrate, means for reducing the volume of the compartments of material to be filtered for compression thereof after the formation of a filter cake, and means for removing from the filter press the filter cake obtained after compression.

The invention also relates to a filtering process implemented in such a device, in particular for the filtration of brewery wort, comprising the introduction of a material to be filtered into each of the compartments of material to be filtered, a possible washing of this material, a compression of the material to be filtered possibly washed by reduction of the volume of the compartments of material to be filtered, an evacuation of the washing solution and the filtrate which have passed through the filtration means, a cleaning of the filter press and an evacuation of the filter cake from the filter press.

Filter presses of the kind described above are already known. Filter presses known as chambered plates or plates are known in particular (see for example patent applications r 25 in France No. 2.38 * 1.526 and No. 2.398.529, the patent in the United States of America No. 3.926 .811 and European patent application No. 81.715). In these filter presses each filter chamber is formed 5 / vf r 30 3

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by two filter plates assembled, each plate comprising a peripheral frame and two front walls, at least one of which is a flexible membrane and partially movable towards the compartment of material to be filtered under the action of a fluid under pressure, 5 thereby forming a means of reducing the volume of the compartment of material to be filtered. Each flexible membrane supports a filtration means in the form of a towel or filter cloth movable with the membrane, the collecting chamber for the filtrate being formed between the filter cloth and a profiling provided in the membrane to drain the filtered liquid. These membranes are fixed to the frame at their periphery and, in the case where the supply is from the center, also to the supply duct. These front walls, costly because requiring very complicated machining to enable them to be effective, exhibit rapid aging under the conditions to which they are subjected. In addition, they generally only allow an entirely insufficient axial displacement in certain fields such as for example the brewery where the thickness of the compartments of material to be filtered must advantageously be able to be of the order of 30 to SO mm. The filter cake obtained in the filter chambers can easily adhere to the filter cloths, which are also made of deformable material. Finally, complicated and costly devices for separating the filter cake after the filter press has been cleaned are often necessary.

Filter presses are also known in which each compartment of material to be filtered is formed between, on the one hand, a flexible membrane and, on the other hand, a filter cloth or towel resting on a grooved plate for draining the filtrate. (for example the LAROX CF filter press). The cloth or filter towel must be stretched to take the filter cake out of the plate, then it is unwound outward to allow its evacuation, which requires complicated and expensive equipment.

Finally, as in the known devices described above, the filter cloths are made of deformable material, for example textile material, and, under the conditions to which they are subjected, they undergo rapid wear and must be frequently replaced.

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Finally, known in particular for the filtration of brewery wort, filter presses of the current type, that is to say allowing only filtration, without compression step (see for example the Belgian patents n ° 844.362 and 886.465 ). These filters-pres-5 ses may include, to form the filtering chambers, empty frames interposed between the plates supporting the filtration means. These are always towels or filter cloths which can optionally be supported on large mesh metal screens serving as means for supporting the filtration means.

These devices obviously have a lower efficiency given the absence of compression of the filter cake.

The object of the present invention is to avoid the problems posed by known devices and to develop a simple, inexpensive and very robust filtering device which is applicable even in cases where the filtering chambers require 'reach great thicknesses, as is the case when filtering brewery wort.

This problem is solved, according to the invention, by a device as described at the start, in which, as filtration means, each filtering chamber only comprises a resistant and non-deformable filtering medium under the operating conditions of the device and having due1 compartment side of the material to be filtered, outside of the passage openings for the liquid, a smooth and flat face. Advantageously, as filtration means, each filtering chamber comprises at least one screen, mesh, fabric or perforated metal plate whose openings have on the compartment side of the material to be filtered a dimension of the order of 50 to 400 microns, this dimension preferably widening in the direction of the filtrate collection compartment.

According to an embodiment of the invention, each filter chamber comprises a plate or frame supporting a means for reducing the volume of the compartment of material to be filtered and a plate or frame supporting a filtration means, each material compartment to be filtered being limited frontally 35. j! fj / / 1 / * · € 5 between the filtration means and the compartment volume reduction means, and the filtration means is supported at the front end, located on the compartment side of the material to be filtered of the panel or frame who supports it.

5 According to a particular embodiment of the invention, the means for reducing the volume of the compartment of material to be filtered is supported on a plate or frame, the peripheral edge of the filtration means side of which is applied against the opposite edge of the plate or support frame for the filtration means in the assembly position of the filter press, and said volume reduction means is impermeable to the material to be filtered and is supported inside its remote support frame of said peripheral edge and movably in the direction thereof.

According to another embodiment of the invention, each filtering chamber comprises an independent empty frame between the filtration means and the means for reducing the volume of the compartment of material to be filtered and a frame or support plate for said reduction means in volume, and the latter is impermeable to the material to be filtered and is supported on its support frame so that it can be moved through the empty frame, in the assembly position of the filter press.

According to the invention, in the filtering process, as described at the beginning, the cleaning includes a spacing by axial translation between the filtration means and the other elements 25 forming the compartments of material to be filtered and an evacuation of the filter cake, then always completely kept in these compartments.

Other details and particularities of the invention will emerge from the description given below, without implied limitation and with reference to the accompanying drawings.

• Figure 1 shows a perspective view, after defatting, of the frames and plates forming a filter chamber of a filter press according to the invention. The guides and supports for these frames and plates, known per se, have not been shown to allow easier reading. 1 1 i / 6 * *

2 shows a view in axial section of an alternative embodiment, in the assembled state of the filter press, in a step preceding the compression.

FIG. 3 partially shows a view similar to FIG. 2, in the compression step.

Figure 4 partially shows a view similar to Figures 2 and 3, in the step of removing the filter cake.

FIG. 3 represents a sectional view of a detail of a filtration means according to the invention, along the line V-V of FIG. 1.

Other details and particularities of the invention will emerge from the description given below, without implied limitation, and with reference to the attached drawings.

As can be seen from FIG. 1, each filter chamber 15 of the filter press comprises a filter means 1 which is non-deformable under the operating conditions of the filter press, for example in the form of a wire mesh 2 supported on a frame 3, this filtration means dividing the filtering chamber into a compartment of material to be filtered 4 (see FIG. 2) and a compartment 20 for collecting 5 of the filtrate or washing solution (see FIG. 2).

The compartment of material to be filtered 4 is, in the embodiment according to FIG. 1, formed between the wire mesh 2, an independent empty frame 6 into which opens a supply duct 7, for the material to be filtered, and a elastic membrane 8 in the form of a single sheet, for example made of natural food-grade rubber, and fixed to a support frame 9.

The latter, in the embodiment illustrated in Figure 1, is closed on its front side opposite by a second membrane 10 which will be used in the adjacent filter chamber. In the chamber 30 formed between these two membranes 8 and 10 and their support frame opens a supply duct 14 for pressurized fluid, for example compressed air.

The filtrate collection compartment 3 is, in the embodiment of FIG. 1, enclosed between the wire mesh 2 and a plate or panel comprising a frame 11 ft * * 7 closed by a partition 12, placed at a short distance on the front side of the frame 11 and preferably having a profiling, for example grooves, for draining the filtered liquid downwards, where it is collected, in a manner known per se, in the frame 11 and discharged through the conduit output 13.

► As can be seen, each of the frames 3, 6, 9 and 11 is provided with two lateral projections 23 for their support on known and not shown support and guide means. In addition, during the defatting, that is to say in the position shown in the figure, all these frames, simply applied one against the other during the operation of the filter press, can separate from each other. other.

FIGS. 2 to 4 show another embodiment of the invention which differs mainly from the previous one by the fact that the filtration means 2 is fixed directly to the frame 11 and that the frame 6 remains, for all the operations, including the cleaning, secured to the frame 9. It could be envisaged that it is in one piece with the latter or that it remains integral! of the latter, for example by bolting, but that it can be | 20 separate, if necessary, for example when it is necessary to access the membrane 8.

As can be seen in Figures 2 to 5, the partition 12 between two filter chambers is formed of a structure of rigid material, for example a sheet of stainless steel.

; 25 This sheet is fixed inside the frame 11 so as to divide it 1 axially in two. On the frame 11 the wire mesh is fixed \ at one of its front ends, so as to be · flush with the side | front 16 (see Figure 4) of the frame 11. Similarly at its other front end j, the filter means 15 of the neighboring filter chamber S 30 is fixed identically.

I As can be seen in Figures 2 to 5, the frame 9 is integral with the empty frame 6, the flexible membrane 8 being sandwiched f between the two frames. Likewise the membrane 10 is sandwiched between | the frame 9 and the empty frame 17 of the neighboring filter chamber.

1 35 Between them is formed inside the frame 9 a chamber as / i% fj * s fluid under pressure 18. This could obviously also be divided in two either by a watertight bulkhead or by a bulkhead to avoid floating membranes. The membranes serve as means for reducing the volume of the compartments of material 5 to be filtered when they are inflated by entry of pressurized fluid. in room 18. They can also, as will be seen below, serve as means of evacuating the filter cake from the filter press.

The membranes in the devices according to the invention 10 can therefore be simple sheets of very flexible rubber, for example of food-grade natural rubber, so that under the action of the fluid under pressure, they can extend without problem towards axial over a distance of the order of 30 to 80 mm. The material used is therefore inexpensive, it does not require any particular machining to obtain a special profile or perforations, and the membranes can be easily fixed to the frame 9, for example by gluing on its front faces. They can also be easily replaced, even in the case illustrated in FIG. 2, where it suffices to unbolt the two frames 6 and 9 and to remove the membra-20 not 8 sandwiched between them. This replacement therefore does not in any way require replacement of the entire frame supporting the membrane, as is the case in known devices.

Each of the filter membranes of the devices according to the invention comprises, as filtration means, only a resistant and non-deformable filter medium under the conditions of filtration and compression and having * on the compartment side. of material to be filtered, outside of passage openings 19 for the filtrate, a smooth and flat face 20. In Figure 5 is illustrated an embodiment of such a filter medium. It consists of a stainless steel lattice in two layers, the wires 21 on the compartment side of the material to be filtered being arranged substantially parallel to one another at a distance of between 50 and 400 microns. The faces 20 between the passage openings 19 thus formed are flattened and arranged so as to form a single plane. These wires are held together by underlying transverse wires 22 which are welded to them and are arranged at a greater distance one from the other. '9' · on the other. The passage openings 19 widen in the direction of the filtrate collection compartment. This allows particles larger than the passage openings to be retained on the surface and prevents particles passing through the latter from obstructing them. As a trellis of this kind, we know a trellis

R

, marketed by BEKAERT under the name of Trislot

Therefore, in the filter presses according to the invention, filtration means are used which are very resistant to the filtering and compression conditions and which do not undergo any deformation during their use.

10 They almost never have to be exchanged, which avoids the frequent replacement costs of cloths or filter towels of known devices. The filter cake almost does not adhere to their surface which facilitates the cleaning. It should be noted that during the latter the filtration means is separated from the other 15 elements by simple translation.

The operation of the device according to the invention, illustrated in FIGS. 2 to 4, will now be described in more detail:

In FIG. 2, the frames and plates of the filter press 20 have just been assembled and pressed one against the other in a known manner and not shown. The material to be filtered is then introduced through the conduit 7 into the compartment k of the empty frame 6, under a certain pressure. Filtration then occurs through the trellis 2, the liquid phase flowing through the latter and being collected 25 in the harvesting chamber 5 then evacuated by the outlet conduit 13. The solid phase is on the other hand retained by the lattice 2. In the brewery sector, it is desirable for the compartment Ψ to have a certain thickness, preferably up to 80 mm.

Indeed, it is desirable that a small thickness of solid material 30 has time to deposit against the lattice for filtration to be fully effective.

Then, washing water is introduced into the apparatus, for example through the same conduit 7 and the washing solute passed through the trellis 2 is collected in the harvesting chamber 5 where 35 3.

10

1 I

it is drained downwards through the partition 12 and discharged through the outlet conduit 13.

When an optimal amount of solute has been collected, compression of the cake can begin (see Figure 3). This compression is caused by the swelling of the elastic membrane, obtained by the introduction of pressurized fluid inside the chamber 18. During this swelling, the membrane deforms and moves in the direction of the trellis. filtration 2 which has the effect of reducing the volume of the solid material compartment 10 and of compressing the solid phase against the filtration mesh 2.

Given its great flexibility, the membrane conforms very well to the internal periphery of the empty frame 6. During this operation, the duct 7 is closed, and a compressed cake is formed between the membrane and the lattice as shown in dotted lines on Figure 3.

In Figure U, the defatting of the filter press is shown. During this operation, there is a separation by axial translation between the filtration mesh and the other elements forming the compartment of material to be filtered, that is to say the empty frame 6 and the membrane 8. It does not 'There is therefore no deformation of these elements during the unraveling or detachment between them by tearing off, as is the case in known devices using filter cloths.

In the embodiment illustrated in FIGS. 2 to 2, the evacuation of the filter cake is effected by an additional swelling of the membrane 8, as shown in FIG. 4, the membrane pushing the filtration cake out of the frame k. The cake then falls into a hopper not shown.

In the exemplary embodiment illustrated in FIG. * 30 1, during the defatting, the wire mesh 2 supported on its own frame 3 and the empty frame 6 are separated from the other frames 11 and 9. Then, an inclination is imparted to the frame 6, or it is subjected to a shock or vibration and the filter cake falls into a hopper not shown.

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It should be understood that the present invention is in no way limited to the embodiments described above and that many modifications can be made without departing from the scope of this patent.

5 One could for example provide an arrangement where "the frames 9 and 11 would be identical and each support a membrane 8 on one side and on the other would have a grooved partition 12, which would allow an arrangement in the same direction of all filtering chambers.

One could also provide an arrangement along a vertical axis of the chambers. The cake would then be collected by gravity on the membrane 8, during the degreasing, then evacuated for example by scraping. One could also imagine a lateral displacement of the frame 6 carrying with it the filter cake and its fall 15 by gravity next to the filter press.

It is also possible to provide other types of non-deformable filtration means than that illustrated in FIG. 5. It is conceivable to use screens, perforated sheets or metal plates for example.

20 Finally, the field of brewing is not the only field of application of the invention and it is obvious that any technical field using pfêsses filters is concerned.

One can also imagine a single evacuation of adjacent rooms, for example by omitting the separating partition 25 12.

Finally, it is also possible, in a manner known per se, to have a general collector for all the filtering chambers.

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Claims (16)

1. Filtering device of the filter press type, in particular for the filtration of brewery wort, comprising plates and possibly assembled frames forming between them filtering chambers 5, at least one inlet in each filtering chamber for the introduction of the material to be filtered, filtration means separating in each filtering chamber a compartment of material to be filtered from a compartment for collecting the filtrate and the washing solution, at least one outlet for the filtrate, means for reducing the volume compartments of material to be filtered for compression thereof after the formation of a filter cake, and means for removing from the filter press the filter cake obtained after compression, characterized in that, as means filtration chamber, each filtration chamber only includes a resistant and non-deformable filter medium under the operating conditions of the device and having on the mat compartment side filter to be filtered, outside of the passage openings for the liquid, a smooth and flat surface. 2. Filtering device according to claim 1, characterized in that, as filtration means, each filtering chamber comprises at least one screen, mesh, fabric or metallic perforated plate, the openings of which have, on the compartment side of the material to be filtered, a dimension. of the order of 50 to W0 microns. 3. Filtering device according to claim 2, characterized in that said dimension of the above-mentioned openings widens in the direction of the filtrate collection compartment. 4. Filtering device according to any one of claims 1 to 3, characterized in that each filtering chamber comprises a plate or frame supporting a means for reducing the volume of the compartment of material to be filtered and a plate or frame supporting a filtration means, each compartment of material to be filtered being bounded frontally between the filtration means and said volume reduction means, and in that the filtration means is supported at the front end, located \ // - · * on the compartment side of the material to be filtered, of the plate or frame which supports it. 5. Filtering device according to claim 4, characterized in that the filtration means is supported on a plate ij which comprises a frame at the peripheral edge of which is fixed the filtration means and a partition, preferably grooved vertically which closes the frame at a certain distance from the filtration means, forming with them said compartment for collecting the filtrate and the washing solution. jq 6. Filtering device according to claim 4, characterized in that the filtration means is supported on an independent frame and in that each filtering chamber comprises, on the side of the filtration means which is opposite to the compartment of material to be filtered , a plate formed by a peripheral frame ^ and a partition, closing the frame at a certain distance from the edge of the frame directed towards the filtration means, the support frame of the filtration means and the aforementioned plate forming with the means filtering said compartment. collection of the filtrate and the washing solution. 2q 7. Device according to any one of claims if to 6, characterized in that the means for reducing the volume of the compartment of material to be filtered is supported on a plate or frame, the peripheral edge of which is on the filtering side, is applied against the opposite edge of the plate or support frame 25 of the filtration means, in the assembly position of the filter press, and in that said volume reduction means is impermeable to the material to be filtered and is supported at inside the frame remote from said peripheral edge and movable in the direction thereof. 3Q 8. Device according to any one of claims 4 to 6, characterized in that each filtering chamber comprises an independent empty frame between the filtration means and the means for reducing the volume of the compartment of material to be filtered and a frame or support plate of said volume reduction means, 35 and in that the latter is impermeable to the material to be filtered:> U> a fc and is supported on its support frame so as to be able to be moved through the frame empty, in the filter press assembly position. 9. Device according to any one of claims 4 to S, characterized in that the plate or frame supporting the volume reduction means of the compartment of material to be filtered from a filtering chamber supports the volume reduction means from the material compartment to be filtered from the adjacent filter chamber. 10. Device according to any one of claims 10 tions 5 to 9, characterized in that the grooved partition closing a filtration chamber behind its filtration means simultaneously closes the adjacent filtration chamber, behind the filtration means of the latter . 11. Device according to claim 4, characterized in that the compartment for collecting the filtrate and the washing solute formed in a filtering chamber behind each filtration means also serves as a collecting compartment for the filtrate and the washing solute for the adjacent filter chamber. 12. Device according to any one of claims 20 tions 1 to 11, characterized in that the compartments of material to be filtered have an axial dimension between 30 and 80 mm. 13. Device according to any one of claims 1 to 9, characterized in that the means for reducing the volume of the compartments of material to be filtered are flexible elastic membranes 25, deformable under the action of a fluid under pressure. 14. Device according to claim 13, characterized • in that the membranes are simple sheets, fixed by gluing or any other suitable manner on their support. 15. Device according to any one of claims 1 to 7 and 9 to 14, characterized in that the means for removing the filter cake are constituted by the means for reducing the volume of the compartments of material to be filtered. 16. Device according to any one of claims 8 to 14, characterized in that the means for evacuating the filter cake comprise means making it possible, during the /// 4t when the filter press is defeated, to tilt the empty frame, to subject the latter or the cake to a shock or to make them vibrate. 17. Filtering process implemented in a filtering device of the filter press type according to any one of the claims 5 to 16, in particular for the filtration of brewery wort, comprising the introduction of a material to to filter in each of the compartments of material to be filtered, a possible washing of this material, a compression of the material to be filtered possibly washed by reduction of the volume of the compartments of material to be filtered, an evacuation of the washing solution and of the filtrate which have passed through the filtration means, a cleaning of the filter press and an evacuation of the filter cake from the filter press, characterized in that the cleaning includes a spacing by axial translation between the filtration means and the other elements 15 forming their respective compartment for the material to be filtered and an evacuation of the filter cake, still kept in these compartments. 1S. A method according to claim 17, characterized in that the evacuation of the filter cake takes place by tilting the compartments of material to be filtered and / or by exposing them to shocks or vibrations. 19. Method according to * claim 17, characterized in that, when, during the unpacking, the means for reducing the volume of the compartments of material to be filtered are provided to remain integral with these, the evacuation of the cake filtration takes place by further reducing the volume of the compartments of material to be filtered. 30 Drawings î ..... ί ........ boards .pages of which ....... <$ ....... cover page description pages - i'f- pages of claim ...... y /! .... descriptive abbreviation Luxembourg, le "7 OCT. 1985 35 The agent / /