The present invention relates to the field of filtering, more precisely the present invention concerns a pore roller based apparatus for the separation of dry matter from a medium.

Background of invention

Separation of dry matter from liquid is known in the art. Methods such as precipitation, centrifugation and filtering are commonly used for separation purposes in a vast number of industries. The latter separation method is relevant for the present invention.

An efficient method for separating dry matter from liquid was presented in WO

03/055570 disclosing a filtration apparatus providing an enclosed pressure regulated separation chamber wherein a suspension is accumulated on a filter which is passed through a set of solid impermeable rollers, whereby the pressure exerted by the rollers separates liquid from the suspension. This roller based principle was improved in WO 2008/131780 where a filtration apparatus based on one or more pore rollers was disclosed. A pore roller is a roller with a surface comprising pores allowing permeability for fluid, in fluid contact with a channel for guiding liquid to a filtrate outlet. Thus, the pressure exerted by the rollers guides the liquid inside the pore roller through the pores in the surface. The end products are the filtrated liquid and a dry filter cake.

Summary of invention

In order to ensure a high efficiency of the separation process it is necessary to sustain a high contact force, i.e. tension, between the rollers but it may be difficult to position the rollers relative to one another such that a sufficient and stable contact force between the rollers is obtained. Furthermore, when the pore roller based filtration apparatus is used in the food industry an efficient cleaning of the apparatus is compulsory in order to ensure sufficient hygienic control and access to the components that are in contact with food are therefore necessary. A first aspect of the present disclosure therefore relates to an apparatus for the separation of dry matter from a medium, comprising a pressure regulated separation chamber defined, in cross section, by a plurality of rollers mounted between opposing sidewalls, each of said rollers having a shaft adapted to be engaged with the sidewalls, a filter arranged so that it passes between at least one set of said rollers consisting of a pore roller and one other roller, means for establishing a pressure difference across the filter, means for passing filter and filter cake through the set of rollers, and a closure mechanism configured to control the transverse tension between the rollers.

A further aspect of the present disclosure relates to an apparatus for the separation of dry matter from a medium, comprising a pressure regulated separation chamber defined, in cross section, by a plurality of rollers mounted between opposing sidewalls, each of said rollers having a shaft adapted to be engaged with the sidewalls, a filter arranged so that it passes between at least one set of said rollers consisting of a pore roller and one other roller, means for establishing a pressure difference across the filter, and means for passing filter and filter cake through the set of rollers. Yet a further aspect of the present disclosure relates to an apparatus for the separation of dry matter from a medium, comprising a separation chamber defined, in cross section, by a plurality of rollers, wherein said chamber is capable of being pressure regulated, and wherein at least one of said rollers is a pore roller having a surface with pores allowing permeability for the medium, and furthermore having at least one channel for guiding the filtrate to the filtrate outlet, said channel being in fluid contact with the pores of the surface, at least one filter means arranged so that it passes between at least one set of rollers consisting of a pore roller and one other roller, means for establishing a pressure difference across the at least one filter means, means for contacting at least one filter means with a suspension of dry matter and medium, and means for passing the at least one filter means and filter cake through said at least one set of rollers, and, optionally, means for removing filter cake.

In a preferred embodiment of the invention one, two or more of the rollers comprises a drum motor configured for rotating said roller(s). A drum motor (sometimes referred to as a motorised pulley) is a geared motor drive enclosed within a tubular shell providing a single component driving pulley. A drum motor typically comprises a motor (e.g. electric or hydraulic) fixed to a stationary shaft at one end of the drum and directly coupled through the motor's rotor pinion to an in-line gearbox which is fixed to the other stationary shaft. The torque is transferred from the motor via the gearbox to the drum shell through a coupling or geared rim attached to the shell or end housing. The only moving external parts are the drum shell and bearing housing. Drum motors are advantageously used in the food or pharmaceutical industry because the drum motor can be designed to withstand hygienic cleaning and service intervals can be very long. A drum motor can therefore advantageously be integrated in one or more of the rollers and the exposed drum shafts become the shafts of the corresponding rollers and the shafts can therefore be attached to the sidewalls. These shafts do not rotate during operation of the apparatus.

The filter may be a filter belt and/or the filter may be a filter attached to the pore roller(s).

Further details about various technical features and the operation of the present apparatus (without the herein disclosed closure mechanism) can be seen in WO 03/055570 and WO 2008/131780.

Description of Drawings

The present invention will now be described in more detail with reference to the drawings.

Fig. 1 a-b show top and side view cross sectional illustrations of one embodiment of the filtering apparatus in an open configuration.

Fig. 2a-b show top and side view cross sectional illustrations of the filtering

apparatus in fig. 1 in a closed configuration.

Fig. 3a-b show top and side view cross sectional illustrations of one embodiment of the filtering apparatus in an open configuration.

Fig. 4a-b show top and side view cross sectional illustrations of the filtering

apparatus in fig. 3 in a closed configuration.

Fig. 5a-b show top and side view cross sectional illustrations of one embodiment of the filtering apparatus in a closed configuration.

Fig. 6a-c show different embodiments of the closure mechanism.

Fig. 7a-c show different embodiments of the closure mechanism.

Fig. 8a-c show top and side view cross sectional illustrations of one embodiment of the filtering apparatus with eccentric shafts. Fig. 9a-b show top view cross sectional illustrations of one embodiment of the filtering apparatus with eccentric shafts.

Fig. 10 shows a pore roller with a drum motor.

Fig. 1 1 shows a roller with a drum motor.

Fig. 12 shows one embodiment of the filtering apparatus with a housing.

Fig. 13 shows a top view cross section of the filtering apparatus in fig.12.

Fig. 14 shows a side view cross section of the filtering apparatus in fig. 12

Definitions

For the sake of clarity of the present text the term "separation" is used synonymously with the term "filtering". By the term "filter cake" is meant an accumulation of dry matter before liquid is removed according to the present invention.

By the term "filter belt" is meant a physical filter upon which a filter cake of a different material than the filter belt is obtained and being passed between two rollers. The term "filter belt" is used interchangeably with the term "filter".

By the term "pore roller" is meant a roller with a surface comprising pores allowing permeability for fluid, e.g. the medium, and furthermore having at least one channel for guiding filtrate to the filtrate outlet such that the channel is in fluid contact with one or more of the pores of the surface.

Detailed description of the invention

As stated above the closure mechanism of the present apparatus is configured to control the transverse tension between the rollers 1 . The provision of a closure mechanism is an advantage when assembling the apparatus after cleaning to ensure and control the tension, i.e. contact force, between the rollers 1 to provide for the maximum efficiency of the filtering process. The closure mechanism may further be adapted to control the distance, i.e. transverse distance between the rollers 1 whereby cleaning of the rollers 1 is eased. E.g. the closure mechanism may be configured such that the apparatus may be operated in an open configuration where the apparatus can be cleaned while the rollers are separated from each other and possibly rotating concurrently. Thus, the closure mechanism may be configured to 1 ) open the apparatus to provide access to the separation chamber, and 2) close the apparatus, seal the separation chamber 1 1 and enforce transverse tension between the rollers 1 1 . The sidewalls 2 preferably comprise bearing housings 6 adapted to the roller shafts 3.

One embodiment of the present apparatus comprises sealing elements 8 located between the rollers 1 and their corresponding sidewall 2. Sealing elements 8 are provided to ensure fluid and/or liquid tightness of the apparatus during filtering operation. The sealing elements 8 may be mounted by means of at least one elastic element 7, such as a spring, configured to separate the sealing elements 8 from their corresponding roller 1 when the sidewalls 2 are longitudinally displaced from each other. This mounting configuration of the sealing elements 8 can help to provide a better cleaning of the apparatus because if the sidewalls are longitudinally displaced from each other the elastic elements may ensure that a (longitudinal) gap is provided between the sealing element 8 and the corresponding sidewall 2 and the

corresponding roller 1 , e.g. as illustrated in figs. 1 b and 3b. In one embodiment the closure mechanism is configured such that a longitudinal displacement of the opposing sidewalls 2 provides a transverse displacement of at least two of the rollers 1 and/or the shafts 3 of at least two of the rollers 1 . Thus, at least one, two, three or four rollers 1 may be mounted such that a transverse displacement of said at least one roller 1 is provided by means of a longitudinal displacement of the opposing sidewalls 2. By linking the transverse positioning of the rollers 1 to a longitudinal displacement of the sidewalls 2, the pressure and tightness between the rollers 1 can be increased by adjusting the distance between the sidewalls 2. One example is illustrated in figs. 1 and 2. Fig. 1 a is a cross-sectional top view of one embodiment of the present apparatus comprising four rollers 1 , each roller having a centred shaft 3. The separation chamber 1 1 is defined by the four rollers 1 . Fig. 1 b is a cross-sectional side view along the line A-A in fig. 1 a. Two rollers 1 are visible with the opposing sidewalls 1 with bearing housings 6 for the shafts 3. The apparatus in fig. 1 is in an open configuration with (transversal) gaps between the rollers 1 and

(longitudinal) gaps between sealing elements 8 and the sidewalls 2 and gaps between sealing elements and rollers 1 provided by means of the springs 7. In general it is advantageous if the distance between the opposing sidewalls can be controllably adjusted, also independent of the closure mechanism, thereby making it possible to adjust and control the end sealing of the rollers, which may help to ensure that the pore rollers are mounted in a fluid tight mounting such that the filtered liquid does not leak unwanted.

In one embodiment of the invention at least one of the roller shafts comprises a tip that is at least partly pointed. A pointed tip may help to ensure an easier fit between the sidewalls 2 and the roller shafts 3. Furthermore, a part of the sidewall that engages with a roller shaft may have a substantially funnel shaped structure. The funnel shaped structure may be provided to function as a guide to a roller shaft 3 when the sidewalls 2 are longitudinally displaced relative to each other. If the sidewalls 2 are longitudinally displaced the roller shafts 3 will be guided inside the funnel shaped structure and thereby be transversally displaced. A part of the sidewall 2 that engages with a roller shaft 3 may comprise at least one surface 5 that is inclined with respect to the axis of rotation of the rollers 1 . Correspondingly a part of the sidewall 2 that engages with a roller shaft 3 may comprise at least one surface 4 that is inclined with respect to the axis of rotation of the rollers 1. These inclined surfaces may form a funnel shaped structure. Thus, the tip of at least one of the roller shafts 3 may comprise at least one inclined surface 4 adapted to engage with the inclined surface 5 of the sidewall 2 when the sidewalls 2 are longitudinally displaced from each other. The inclined surfaces 4, 5 are preferably adapted such that a longitudinal displacement of the sidewalls 2 engages corresponding inclined surfaces 4, 5 of the sidewalls 2 and the shafts 3 resulting in a transverse displacement of said shafts 3.

The inclined surface 4 of the sidewall 2 may comprise a horizontal division. This horizontal division may function almost as a storey partition and can have the function of providing a longitudinal position of the rollers 1 where the filtering apparatus is in an open configuration but at the same time allowing rotation of the rollers 1 , i.e. a cleaning position allowing for cleaning of the rollers 1 while rotating, e.g. as illustrated for the left roller in fig. 1 b.

The apparatus illustrated in fig. 2 corresponds to the apparatus in fig. 1 but in a closed configuration. Compared to fig. 1 b the sidewalls 2 have been longitudinally displaced towards each other such that the roller shafts 3 are firmly integrated with the sidewalls 2 and the bearing housings 6 providing a transverse tension between the rollers 1 thereby sealing the separation chamber 1 1 and tightly closing the gaps between the sealing elements 8 and the rollers 1 and the sidewalls 2.

A further embodiment is illustrated in figs. 3 and 4, almost corresponding to the solution depicted in figs. 1 and 2 with the apparatus in an open configuration in fig. 3 and in a closed configuration in fig. 4. The shaft of the left roller is not symmetric with a single inclined surface 4' facing a single inclined surface 5' of the sidewall 2. Thus, when the sidewalls in the embodiment in figs. 3 and 4 are longitudinally displaced only the left roller with the inclined surface 4' will be transversally displaced, whereas in the solution in figs. 1 and 2 both rollers will be transversally displaced. However, transverse displacement of just one of two adjacent rollers may be adequate to control the tension between the rollers.

In one embodiment the closure mechanism comprises at least one pivot arm arrangement for at least one or two or all of the rollers. This pivot arm arrangement may be adapted for providing a longitudinal displacement of a sidewall and the corresponding roller. An example is illustrated in fig. 5 showing a filtering apparatus in a closed configuration. The pivot arm arrangement 9 provides for the longitudinal displacement of the sidewalls 2 relative to the rollers 1 . The inclined surfaces 4', 5' provides for the transverse displacement of the left roller in fig. 5b when operating the pivot arm 9. Other solutions for providing a transverse displacement of one or more rollers as a result of a longitudinal displacement of the sidewalls may be provided. E.g. if at least two of the rollers comprise shafts that are inclined relative to the axis of rotation of the rollers. One such solution is illustrated in fig. 6a showing the top part of a roller 1 and the corresponding sidewall 2 with the bearing housing 6. The shaft 3 is inclined with respect to the longitudinal axis of the roller 1 . The interface in the sidewall 2 matches this inclined shaft 3 such that when the sidewall 2 is displaced in the longitudinal direction the roller 1 will be displaced in a transverse direction. Another solution is depicted in fig. 6b where the roller 1 comprises a funnel shaped structure into the end of the roller, i.e. with the shaft of the roller not protruding from the roller. The "shaft" 3 is in this case mounted on the sidewall 2. Yet another embodiment is illustrated in fig. 6c where the shaft 3 of the roller 1 comprises one or two guide notches 16 extending longitudinally along the shaft 3. The notches 16 can be seen in the insert to the right of fig. 6c showing a cross-section of the shaft seen along the line A-A. As seen form fig. 6c the notch is not straight but forms an angle. One or more protrusions 15 are provided in the sidewall 2 to match the one or more notches 16. When shaft 3 engages with the sidewall 2 the protrusions 15 will be guided in the notches 16 and the angled trace of the notches 16 will ensure that the roller 1 is displaced transversally when the sidewalls 2 are displaced longitudinally.

In a further embodiment the closure mechanism is configured to directly translated one or two or all of the rollers in a transverse direction, i.e. the transverse position is directly controlled by the closure mechanism. The closure mechanism may be pneumatically operated or operated by one or more toothed racks or operated by nuts and bolts. Examples are illustrated in figs. 7a-c with a pneumatic closure mechanism in fig. 7a mounted on two of the rollers 1 controlling the transverse position of these two rollers 1 such that tension between the rollers is controlled by the closure mechanism. A more simple closure mechanism is illustrated in fig. 7b where the closure mechanism is based on nut & bolt arrangement. A closure mechanism employing a toothed rack is illustrated in fig. 7c. These closure mechanisms can be automatically and/or manually operated.

Another way to provide to transverse tension between the rollers is by having non- centered shafts in some of the rollers. Thus, in a further embodiment at least one, two, three or four or all of the rollers are provided with eccentric or non-centered shafts. The eccentric configuration of one or more of the shafts is preferably adapted to provide a transverse tension of the corresponding roller(s) during rotation of said roller(s).

Correspondingly, at least one, two, three or four of the rollers may be provided with centered shafts. Non-centered shafts are illustrated in figs. 8 and 9, each having four rollers. In fig. 8 two of the rollers 1 have centered shafts 13 and two of the rollers V have non-centered shafts 13. In fig. 9 all four rollers V have centered shafts 13. A cross-sectional side view illustration of a roller V with non-centered shaft 13 is provided in fig. 8a with a drum motor 17 inside the roller 1 '. In fig. 8b the apparatus is in an open stationary configuration (i.e. no rotation of the rollers) with gaps between the rollers 1 , 1 ' and access to the separation chamber 1 1. When the rollers 1 ' with the drum motors 17 begin to rotate in the direction indicated by the arrows, the eccentricity of the shaft configuration 13 will force the outside surface of the two rollers 1 ' towards the other two rollers 1 such that transverse tension is provided between the rollers 1 , 1 ', whereas the shafts 3, 13' are not displaced transversally. The rollers 1 may be passive, i.e. no active rotation mechanism, and they are rotated by the other rollers 1 '. In fig. 9a the apparatus is again in an open configuration and with a closed configuration in fig. 9b. All rollers 1 ' are provided with non-centered shafts 13, thus when the rollers 1 ' begin to rotate the shafts 13 will remain transversally stationary but the outside rotating surface of the rollers 1 ' will be transversally displaced towards each other. When the rollers 1 ' rotate in the directions indicated with arrows in fig. 9a, the roller surface will apply tension towards each other. When the rotation is stopped the apparatus in fig. 8c and 9b will remain in the closed configuration. However, with a slight roller rotation in the opposite direction the roller surfaces will be translated away from each other and bring the apparatus to an open configuration. Thus, the closure mechanism simply need to control the rotation of the rollers 1 , 1 ' in order to close the apparatus, apply tension between the roller surfaces, to stop the apparatus and to open the apparatus.

Fig. 10 shows a more detailed exploded view of one embodiment of a pore roller with a drum motor 1 . The roller has a cylinder 2 and a filter 5 as well as ends 3 and 4 of the roller and weld rings 7 at each end of the roller. The weld rings 7 are located between the cylinder 2 and the ends 3, 4 (respectively) and are provided to ensure that the filter 5 is securely attached to cylinder 2 which is attached to the drum motor 1. At the end of the roller there is also a sealing ring 6. Fig.1 1 shows an embodiment of a roller that is not a pore roller but otherwise similar to fig.10. The roller has an outer shell 4 which e.g. can be made of rubber. As in fig. 10 there is cylinder 1 and a motor 5. At the end of the roller there is an end 2 and a sealing ring 3. The sealing rings 3, 6 are preferably configured for providing a fluid tight closure of the rollers. The sealing effect may be provided with the use of a soft material like rubber.

A further embodiment of the present disclosure relates to a housing to enclose and hold the rollers. By enclosing the apparatus the rollers are better protected and less exposed to e.g. dust, dirt and/or other external particles. The fact that moving mechanical parts are not directly accessible from the outside is also safer for a person operating the apparatus. The housing can also assist the opposing sidewalls in stabilizing the position of the rollers and closure mechanisms. The handling of the apparatus in a housing is also easier; it is easier to hold, move or transport the apparatus with a housing compared to a several exposed mechanical parts. One embodiment of the filtering apparatus with housing is showed in fig. 12. In this embodiment there are four rollers (two pore rollers and two other rollers). The pore roller 2 and the other roller 3 constitute one set of rollers. The rollers are mounted on the opposing sidewalls 1 and 14. Between the opposing sidewalls 1 and 14 and the rollers 2 and 3 there are also plastic plates 9 and 10. In this embodiment the housing 4 is cylinder shaped, which is a suitable shape when the arrangement of rollers is symmetric. A top ring 1 1 holds the housing 4 and the sidewall 14 together. In this embodiment there are also additional housing 5 and 6 for the shafts of the rollers and a top manifold 13 mounted on the sidewall 14. There is a housing 7 for a scraper, which can be used to remove filter cake.

One embodiment of the closure mechanism is illustrated in fig. 12 in the form of a nut and bolt arrangement fixed to a holder attached to the sidewall. A holder 8 for such a nut and bolt arrangement is fixed to the sidewall 14. The bolt can be screwed to control the transverse position of one of the rollers. This is a useful way to keep the roller in a fixed and precise position and thereby control the tension between the rollers.

The opposing sidewalls 1 and 14 in fig.12 may be detachable. This has the advantage that even though the mechanisms of the apparatus are enclosed in a housing, the rollers, scraper or other mechanical parts can be conveniently removed to be repaired or washed outside the housing, or exchanged against new parts.

In one embodiment of the invention, the housing comprises one or more openings (windows) on the housing surfaces parallel to the shaft axis. These openings can be used to give access to the mechanical parts inside the housing, which is useful when the apparatus or parts of the apparatus is/are to be washed or repaired without detaching the housing or the opposing sidewalls. An example of an opening in a housing (15) is shown in fig.12. The openings may also have flaps that can opened and closed to ensure that no mechanical parts are exposed while the apparatus operates, but the parts can be accessed when the apparatus does not operate. These openings may also be at least partly closed / blocked by netting to prevent a hand or other parts or tools to penetrate the opening and disturb the rotating pore rollers during operation but the netting can ensure that filter cake can still exit the openings. Fig. 13 is a top view of the embodiment in fig. 12. In this figure an example of the placement of housing 2 of the shaft for one of the rollers and a holder 3 for a nut and bolt arrangement is shown. A top ring 1 holds the housing and the sidewall together. The placement of the housing 4 for a scraper, the housing 5 for a pore roller and the top manifold, corresponding to elements 7, 5, and 13 in fig. 12 are also shown.

Fig. 14 is a cross-sectional side view along the line A-A in fig. 13 showing two pore rollers, a separation chamber 2, a top manifold 3, a filter 4, a housing 5 and an opening 6 in the housing. A further embodiment of the invention relates to the filtering apparatus being configured such that the angular orientation of the apparatus can be controlled and/or adjusted, i.e. such that the axis of rotation of the rollers can be controllably adjusted. Preferably the apparatus is configured such that it can be rotated around an axis orthogonal to the shaft axis (which corresponds to the axis of rotation of the rollers), i.e. such that the entire apparatus can be rotated. Besides the advantages of easier handling, cleaning, assembly and disassembly of the apparatus, there are several advantages related to the filtration performance in having a rotatable apparatus where the angular orientation of the apparatus can be controlled. If the apparatus is placed upright with a vertical axis of rotation of the rollers (i.e. with one of the opposing sidewalls down and the other sidewall up) it has the disadvantage that liquid may flow downwards on the inside of the pore rollers and wet the filter cake, which preferably must be kept dry.

If the apparatus instead has a horizontal position with a horizontal axis of rotation of the rollers, there will be liquid in the lower part of the pore roller (the part closest to the ground). This part of the pore roller rotates towards the center of the separation chamber. This means that filter cake will move away from the center of the separation chamber upwards with the part that rotates out from the center, where there is no liquid. A horizontal position may also avoid an uneven load on the rollers, which may otherwise be a consequence of the cake moving downwards if the apparatus is in an upright position. Thus, in many situationa a horizontal position is preferred over a vertical position during operation of the apparatus.

However, to ease to flow of filtrated liquid towards the filtrate outlet, typically located at the bottom of the pore rollers, it may also be advantageous to lean the apparatus slightly from the horizontal position to ease to flow of filtrated liquid towards the filtrate outlet. It is therefore desirable that the user can control the angular orientation of the apparatus to obtain optimal performance. In one embodiment of the presently disclosed filtration apparatus the optimal orientation of the apparatus during filtering operation is with the axis of rotation of the rollers forming an angle between 0 and 45 degrees relative to the horizontal plane, or between 1 and 30 degrees, or between 0 and 10 deg, or between 10 and 15 deg, or between 15 and 20 deg, or between 20 and 30 deg, or between 30 and 40 deg.

One way to control the angular orientation of the apparatus is by means of a mounting, e.g. configured to hold the housing, e.g. such that apparatus/housing is rotatable around an axis orthogonal to the axis of rotation of the rollers. The mounting is preferably a stable construction made of a rigid material, e.g. metal. One way to control the angular orientation precisely is to have a wheel that can be turned to adjust the orientation of the apparatus. Since the apparatus may be heavy, in another

embodiment of the mounting, the angular orientation of the apparatus may be controlled by an electrical motor, which may improve precision and reduce manual work.

A further aspect of the present disclosure relates to the use of the presently disclosed apparatus for separation of dry matter from products or elements selected from the group of: beer mask, fruit pulp and fruits such as apples, pears, berries, and grapes, and vegetables such as root vegetables such as potatoes, carrots, etc.

Further details of the invention

The invention will now be described in further detail with reference to the following numbered items: An apparatus for the separation of dry matter from a medium, comprising a pressure regulated separation chamber defined, in cross section, by a plurality of rollers mounted between opposing sidewalls, each of said rollers having a shaft adapted to be engaged with the sidewalls,

a filter arranged so that it passes between at least one set of said rollers consisting of a pore roller and one other roller,

means for establishing a pressure difference across the filter,

means for passing filter and filter cake through the set of rollers, and a closure mechanism configured to control the transverse tension between the rollers. The apparatus according to item 1 , wherein the apparatus is configured such that the angular orientation of the apparatus can be controlled and/or adjusted.

The apparatus according to any of preceding items, wherein the apparatus is configured such that the angular orientation of the apparatus around an axis orthogonal to the axis of rotation of the rollers can be controlled and/or adjusted.

The apparatus according to any of preceding items, wherein the angular orientation of the apparatus is controlled manually.

The apparatus according to any of preceding items, wherein the angular orientation of the apparatus is controlled by a wheel or handle.

The apparatus according to any of preceding items, wherein the angular orientation of the apparatus is controlled by an electrical motor.

The apparatus according to any of preceding items, wherein said closure mechanism comprises translation means configured for providing a transverse displacement of at least two of the rollers and/or the shafts of at least two of the rollers.

The apparatus according to any of preceding items, wherein said closure mechanism is pneumatically operated, or operated by one or more toothed racks or operated by nuts and bolts.

The apparatus according to any of preceding items, wherein said closure mechanism comprises translation means configured for providing a transverse displacement of at least two of the rollers and/or the shafts of at least two of the rollers, and wherein said closure mechanism comprises nuts and bolts arrangements attached to the sidewalls.

10. The apparatus according to any of preceding items, wherein said closure

mechanism comprises at least one pivot arm arrangement for at least one two of the rollers.

1 1 . The apparatus according to any of preceding items, wherein the closure

mechanism is configured such that a longitudinal displacement of the opposing sidewalls provides a transverse displacement of at least two of the rollers.

12. The apparatus according to any of preceding items, wherein the closure

mechanism is configured to 1 ) open the apparatus to provide access to the separation chamber, and 2) close the apparatus, seal the separation chamber and enforce transverse tension between the rollers.

13. The apparatus according to any of preceding items, wherein at least one, two, three or four rollers are mounted such that a transverse displacement of said roller(s) is provided by means of a longitudinal displacement of the opposing sidewalls.

14. The apparatus according to any of preceding items, wherein at least one, two, three or four of the rollers are provided with eccentric or non-centered shafts. 15. The apparatus according to any of preceding items 14, wherein the eccentric configuration of one or more of the shafts is configured to provide a transverse tension of the corresponding roller(s) during rotation of said roller(s). The apparatus according to any of preceding items, wherein at least one, two, three or four of the rollers are provided with centered shafts. The apparatus according to any of preceding items, wherein said roller shafts are stationary during operation of the apparatus. The apparatus according to any of preceding items, wherein said roller shafts are rotating during operation of the apparatus. The apparatus according to any of preceding items, wherein at least two of the rollers comprises shafts that are inclined relative to the axis of rotation of the rollers. The apparatus according to any of preceding items, wherein at least one or two of the rollers comprises a drum motor configured for rotating said roller(s). The apparatus according to any of preceding items, wherein at least one of the roller shafts comprises a tip that is at least partly pointed. The apparatus according to any of preceding items, wherein a part of the sidewall that engages with a roller shaft has a substantially funnel shaped structure. The apparatus according to any of preceding items, wherein a part of the sidewall that engages with a roller shaft comprises at least one surface that is inclined with respect to the axis of rotation of the rollers. The apparatus according to any of preceding items, wherein a part of the sidewall that engages with a roller shaft comprises at least one surface that is inclined with respect to the axis of rotation of the rollers and wherein said inclined surface comprises a horizontal division.

The apparatus according to any of preceding items 23 to 24, wherein the tip of at least one of the roller shafts comprises at least one inclined surface adapted to engage with the inclined surface of the sidewall when the sidewalls are longitudinally displaced from each other.

26. The apparatus according to any of preceding items 23 to 25, wherein said inclined surfaces are adapted such that a longitudinal displacement of the sidewalls engages corresponding inclined surfaces of the sidewalls and the shafts resulting in a transverse displacement of said shafts.

27. The apparatus according to any of preceding items, further comprising sealing elements located between the rollers and their corresponding sidewalk

28. The apparatus according to any of preceding items 27, wherein said sealing elements are mounted by means of at least one elastic element, such as a spring, configured to separate the sealing elements from their corresponding roller when the sidewalls are longitudinally displaced from each other.

29. The apparatus according to any of preceding items, wherein the filter is a filter belt.

30. The apparatus according to any of preceding items, wherein the filter is a filter attached to the pore roller.

31 . The apparatus according to any of preceding items, further comprising means for removing filter cake.

32. The apparatus according to any of preceding items, further comprising a

housing extending between the opposing sidewalls and configured to enclose and hold the roller(s).

33. The apparatus according to preceding item 31 , wherein the housing is cylinder shaped.

34. The apparatus according to preceding items 31 -32, wherein the opposing sidewalls are detachable.

35. The apparatus according to preceding items 31 -33, wherein the housing

comprises one or more openings on the housing surface. The apparatus according to preceding items 34, wherein the openings have flaps that can be opened and closed. The apparatus according to preceding items 31 -35, wherein the housing is made of metal. The apparatus according to preceding items 31 -36, further comprising a mounting configured to hold the housing, such that the housing and the apparatus is rotatable around an axis orthogonal to the axis of rotation of the rollers. An apparatus for the separation of dry matter from a medium, comprising

a separation chamber defined, in cross section, by a plurality of rollers, wherein said chamber is capable of being pressure regulated, and wherein at least one of said rollers is a pore roller having a surface with pores allowing permeability for the medium, and furthermore having at least one channel for guiding the filtrate to the filtrate outlet, said channel being in fluid contact with the pores of the surface,

at least one filter means arranged so that it passes between at least one set of rollers consisting of a pore roller and one other roller,

means for establishing a pressure difference across the at least one filter means,

means for contacting at least one filter means with a suspension of dry matter and medium, and

means for passing the at least one filter means and filter cake through said at least one set of rollers. The apparatus of item 39, further comprising any of the features of any of items 1 -31.