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Title:
IMPROVEMENTS TO MEMBRANE PRESSES AND DRAINAGE MEMBERS
Document Type and Number:
WIPO Patent Application WO/2002/024439
Kind Code:
A1
Abstract:
The present invention relates to an improved membrane press (10) and drainage member (34) for use in said press. The drainage member includes a sieve portion (74) and a support portion (76), the sieve portion arranged to prevent a first product from passing therethrough and into said support portion, the support portion being arranged to support said sieve portion. Both the sieve and support portions are made from a flexible material. In the press longitudinal clamping means (36) are positioned within a chamber containing the product to be pressed and are used to hold in position lengths of drainage members located between the clamping means. The clamping means also vertically deform the drainage members to improve upon extracted juice flow and minimise any blockages that may occur.

Inventors:
HESKETH ROBERT WILLIAM THOMAS (AU)
HUXTABLE PAUL STEWART (AU)
CAMPBELL GEORGE GILES (AU)
Application Number:
PCT/AU2001/001191
Publication Date:
March 28, 2002
Filing Date:
September 24, 2001
Export Citation:
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Assignee:
WINE INNOVATION PTY LTD (AU)
HESKETH ROBERT WILLIAM THOMAS (AU)
HUXTABLE PAUL STEWART (AU)
CAMPBELL GEORGE GILES (AU)
International Classes:
B30B9/22; (IPC1-7): B30B5/02; B30B9/22; B30B9/02; B30B15/00
Foreign References:
EP0607932A11994-07-27
US4607570A1986-08-26
EP0524373A11993-01-27
EP0349679A21990-01-10
Attorney, Agent or Firm:
Lesicar, Perrin (Adelaide, S.A. 5000, AU)
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Claims:
CLAIMS
1. A drainage member for use in a membrane press including : a sieve portion and a support portion, said sieve portion being arranged to prevent a first product from passing therethrough and into said support portion; said support portion being arranged to support said sieve portion; wherein said sieve portion and support portion are made from a flexible material.
2. A drainage member for use in a membrane press including : a sieve portion and a support portion, said sieve portion being arranged to prevent a first product from passing through said sieve portion while allowing a second product to pass therethrough and into said support portion; said support portion being arranged to support said sieve portion, and wherein in use a pressure differential exists between an area adjacent said sieve portion and an area adjacent said support portion, so that said second product is caused to pass into said support portion.
3. A drainage member as in any one of the above claims wherein said sieve portion and said support portion are integrally formed.
4. A drainage member as in any one of the above claims wherein the sieve portion and said support portion are elastically deformable so that said drainage member can be readily flexed.
5. A drainage member as in any one of the above claims wherein said support portion includes at least one transport path arranged to direct said second product to an outlet.
6. A drainage member including a sieve portion and a support portion, said sieve portion being arranged to prevent a first product of a predetermined dimension from passing through said sieve portion while allowing a second product to pass therethrough and into said support portion, said support portion including a transport path arranged to direct said second product to a receiving outlet and wherein said sieve portion and support portion are integrally formed.
7. A drainage member as in any one of the above claims wherein said sieve portion and said support portion are elastically deformable and are made of a flexible plastics material.
8. A drainage member as in any one of the above claims wherein said sieve portion includes a plurality of spaced longitudinal sieve elements separated by a sieve gap and wherein said support portion includes a plurality of spaced longitudinal support elements separated by a support gap.
9. A drainage member as in claim 8 wherein said sieve elements are approximately 3 millimeters wide, 3.6 millimetres high and separated by a gap of some 1.8 millimetres.
10. A drainage member as in claim 8 wherein said support elements are approximately 3 millimetres wide, 3.6 millimeters high and separated by a gap of some 7 millimetres.
11. A drainage member as in any one of claims 8 to 10 wherein said sieve elements includes an upper concave surface.
12. A drainage member as in claim 11 wherein the radius of said upper concave surface is some 4 millimetres.
13. A drainage member as in any one of claims 8 to 11 wherein said support elements include a lower concave surface.
14. A drainage member as in claim 13 wherein the radius of said lower concave surface is some 4 millimetres.
15. A drainage member as in claim 12 wherein located between said support elements is a transport path.
16. A drainage member as in any one of claims 8 to 15 wherein said sieve elements and support elements are positioned with their longitudinal axis substantially perpendicular to each other.
17. A drainage member as in any one of claims 8 to 15 wherein the longitudinal axis of support elements and sieve elements are angled to one another.
18. A drainage member as in any one of claims 8 to 17 wherein the sieve gap is of a size to prevent solids of a predetermined dimension from passing therethrough while still allowing satisfactory flow of liquid therethrough.
19. A drainage member as in any one of the above claims wherein said drainage member is some 1200 millimetres in width.
20. A drainage member as in any one of the above claims wherein said drainage member is made of a flexible foodgrade plastics material.
21. A drainage member as in any one of the above claims wherein the drainage member is made from lengths of extruded plastics material welded together to form a grid structure.
22. A drainage member as in any one of the above claims wherein said drainage member is manufactured in large sheets or as a roll that can be cut to the desired size by a user.
23. A membrane press for separating grape juice from grape mash including : a cylindrical vessel adapted to rotate about its longitudinal axis and having an inner surface; said vessel divided into two diametrically opposed chambers by a deformable membrane extending generally across the diameter of said vessel, said first chamber adapted to be pressurised by a fluid said second chamber adapted to hold a product to be pressed; a plurality of longitudinal clamping means located symmetrically around the second chamber inner surface and extending generally parallel to the longitudinal axis of said vessel ; a plurality of draining means extending longitudinally along said vessel and inbetween said clamping means, the edges of said drainage means held in place by said clamping means.
24. A membrane press as in claim 23 wherein said clamping means raises the edge of the draining member away from said inner surface, the drainage member in between adjacent clamping means being of a parabolic cross sectional shape.
25. A membrane press as in either claim 23 or claim 24 wherein said clamping means includes a base and a plate, said drainage member edge adapted to be placed inbetween said base and plate, wherein said plate is adapted to be moved towards said base to thereby clamp the drainage member.
26. A membrane press as in claim 25 wherein said plate is biased away form said base by use of springs extending inbetween the base and plate.
Description:
Improvements to membrane presses and drainage members Field of the Invention The present invention relates to an improved membrane press and to a drainage member used in such a press to separate a liquid from a pulp. Although the invention has particular application in the fruit juice and wine industry the invention should not be considered limited to application therein.

Background of the Invention Numerous machines have been developed to de-juice, de-water and de-oil fruits and other materials. These machines are commonly called presses and are widely used in the fruit juice and wine manufacturing industries. One factor common to these presses is the inclusion of a drainage or sieve member to effect separation between different elements, for example, the solids and the liquids. The efficiency of these machines is heavily influenced by the type and surface area of the drainage member.

One of the most common forms of presses is known as a membrane press.

Such a press includes a horizontally orientated cylindrical shaped vessel that is arranged to rotate about its longitudinal axis. The cylindrical vessel is divided into two diametrically opposed parts by a deformable membrane that is peripheral fixed in proximity to the vessel axis. One portion of the vessel is arranged to receive a product that is to be pressed. The product, for example a wine mash, is pressed against the hard wall of the vessel by the action of the pressurized air on the membrane. Liquid from the mash is then drained from the vessel via an outlet port.

To improve the processing capability of such a press, it is desirable to remove the liquid from the mash as quickly as possible.

Attempts have been made to improve the processing speeds of such presses by incorporating various devices for draining the liquid from the mash. For example it has been known to construct a drainage member extending along the longitudinal axis of the cylinder and having a two-dimensional cross-sectional shape. The drainage

member includes slits or apertures of a size that allows the liquid to pass therethrough but not any of the solid components of the mash such as grape seeds. The liquid can then flow along said drainage member for collection through an outlet port.

There have been a number of difficulties with such drainage devices. For example, some are quite heavy, being made of food-grade stainless steel thereby making them difficult-and cumbersome to install and are accordingly difficult to remove for cleaning purposes. They are also quite cumbersome being relatively long. It will be appreciated by those skilled in the art, that cleaning of the internal components of such compression presses is extremely important in order to ensure the hygiene of the resultant product. In addition, the drainage can at times be poor especially when the mash has already been substantially compressed. At that stage of the process, it takes a relatively long time for any further juice to be extracted from the press.

The present invention seeks to overcome at least some of the aforementioned problems or provide the public with a useful alternative. It provides an improved design of a membrane press utilising an improved form of drainage member. The drainage member has application in a wide range of equipment for different industries.

Summary of the Invention According to a first aspect of the present invention there is provided a drainage member for use in a membrane press including : a sieve portion and a support portion, said sieve portion being arranged to prevent a first product from passing therethrough and into said support portion; said support portion being arranged to support said sieve portion; wherein said sieve portion and support portion are made from a flexible material.

In a further aspect of the invention there is proposed a drainage member for use in a membrane press including : a sieve portion and a support portion, said sieve portion being arranged to prevent a first product from passing through said sieve portion while allowing a second product to pass therethrough and into said support portion; said support portion being arranged to support said sieve portion, and wherein in use a pressure differential exists between an area adjacent said sieve portion and an area

adjacent said support portion, so that said second product is caused to pass into support portion.

Preferably said sieve portion and said support portion are integrally formed.

Preferably the sieve portion and said support portion are elastically deformable so that said drainage member can be readily flexed.

Preferably support portion includes at least one transport path arranged to direct said second product to an outlet.

In a still further aspect of the invention there is proposed a drainage member including a sieve portion and a support portion, said sieve portion being arranged to prevent a first product of a pre-determined dimension from passing through said sieve portion while allowing a second product to pass therethrough and into said support portion, said support portion including a transport path arranged to direct said second product to a receiving outlet and wherein said sieve portion and support portion are integrally formed.

Preferably the sieve portion and said support portion are elastically deformable and are made of a flexible plastics material.

Preferably the sieve portion includes a plurality of spaced longitudinal sieve elements separated by a sieve gap and wherein said support portion includes a plurality of spaced longitudinal support elements separated by a support gap.

Preferably the sieve elements are approximately 3 millimeters wide, 3.6 millimetres high and separated by a gap of some 1.8 millimetres.

Preferably the support elements are approximately 3 millimetres wide, 3.6 millimeters high and separated by a gap of some 7 millimetres.

Preferably each sieve elements includes an upper concave surface.

Preferably the radius of the upper concave surface is some 4 millimetres.

In preference the support elements include a lower concave surface.

In preference the radius of said lower concave surface is some 4 millimetres.

Advantageously located between said support elements is a transport path.

Advantageously the sieve elements and support elements are positioned with their longitudinal axis substantially perpendicular to each other.

In preference the longitudinal axis of support elements and sieve elements are angled to one another.

In preference the sieve gap is of a size to prevent solids of a predetermined dimension from passing therethrough while still allowing satisfactory flow of liquid therethrough.

In preference the drainage member is some 1200 millimetres in width.

In preference the drainage member is made of a flexible food-grade plastics material.

Advantageously the drainage member is made from lengths of extruded plastics material welded together to form a grid structure.

In preference the drainage member is manufactured in large sheets or as a roll that can be cut to the desired size by a user.

In a still further aspect of the invention there is provided a membrane press for separating grape juice from grape mash including: a cylindrical vessel adapted to rotate about its longitudinal axis and having an inner surface; said vessel divided into two diametrically opposed chambers by a deformable membrane extending generally across the diameter of said vessel, said first chamber adapted to be pressurised by a fluid said second chamber adapted to hold a product to 'be pressed; a plurality of longitudinal clamping means located symmetrically around the second

chamber inner surface and extending generally parallel to the longitudinal axis of said vessel ; a plurality of draining means extending longitudinally along said vessel and in-between said clamping means, the edges of said drainage means held in place by said clamping means.

In preference the clamping means raises the edge of the draining member away from said inner surface, the drainage member in between adjacent clamping means being of a parabolic cross-sectional shape.

In preference the clamping means includes a base and a plate, said drainage member edge adapted to be placed in-between said base and plate, wherein said plate is adapted to be moved towards said base to thereby clamp the drainage member.

Preferably the plate is biased away form said base by use of springs extending in-between the base and plate.

The present invention therefore provides for a membrane press utilising a drainage member. The drainage member includes a sieve and a support portion. The sieve portion includes a plurality of spaced longitudinal sive elements. Each sieve element is separated from an adjacent sieve element by virtue of a sieve gap. The support portion preferably includes a plurality of spaced longitudinal support elements.

Located between adjacent longitudinal support elements is a transport path. The sieve elements and support elements are preferably positioned with their longitudinal axis substantially perpendicular to each other. Alternatively, the longitudinal axis of support elements and sieve elements may be angled to one another to shorten the length of travel along the transport pash by the second product to the outlet.

Brief Description of the Drawings The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings, Figure 1 is a perspective view of a typical membrane press and drainage member as previously known;

Figure 2 is a perspective view of a membrane press and a drainage member in accordance with an embodiment o the invention; Figure 3 is a detailed partial exploded perspective view of the drainage member clamping mechanism in accordance with an embodiment of the invention; Figure 4 is a detailed partial perspective view when a drainage member is in a fixed position by use of the clamping member; Figure 5 is a perspective view of the drainage member in accordance with an embodiment of the invention.

Figure 6 is an enlarged view of the drainage member across side'A'marked in Figure 5; Figure 7 is an enlarged view of the drainage member across side'B'marked in Figure 5; and Figure 8 is a schematic cross-sectional view of a membrane press incorporating drainage members according to an embodiment of the invention.

Detailed Description of the Preferred Embodiment The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

Figure 1 illustrates schematically the cross-sectional configuration of a membrane press 10 as currently known. The membrane press 10 includes a cylindrical vessel 12 that is arranged to rotate about its longitudinal axis 14. The cylindrical vessel 12 is divided into two diametrically opposed chambers 16 and 18 by a deformable membrane 20 that is peripheral fixed across the diameter of the vessel.

The first or top chamber 16 of the vessel 12 is arranged to receive a pressurized fluid such as air. A second chamber 18 of the vessel 12 is arranged to receive a product that is to be pressed. The vessel 12 also includes outlets or

discharge ports 22 through which filtered wine juice can be drained from the vessel 12 and an access port 24 through which the wine mash is introduced in the membrane press 10.

Extending longitudinally and secured along the inner wall 26 of the vessel are a plurality of drainage members 28. These drainage members have a two-dimensional cross-sectional shape, typically a square shape configuration. The drainage members include a plurality of slits 30 of a size to allow for the passage of wine juice therethrough. Typically the drainage members are manufactured from a food quality stainless steel and are secured to the inner wall by fixing means such as screws 32 that engage threaded bosses (not shown).

Illustrated in Figure 2 is a membrane press utilising a drainage member according to an embodiment of the present invention. The general construction of the membrane press is as illustrated in Figure 1 there being a membrane 20 partitioning the vessel 12 into first and second chambers 16 and 18 respectively.

Lengths of drainage member 34 extend longitudinally along said vessel in between clamping means 36. The clamping means extend along and away from the inner wall 26 so that the drainage member end 38 in proximity to the clamping means 34 is spaced apart from said wall 26. A locked drainage member then has a curved profile wherein its edges are raised while its middle part 40 is in contact with or close to the wall 26.

Details of the clamping means 36 and its operation is illustrated in Figures 3 and 4. As mentioned above, current drainage members use a threaded boss 42 to lock the drainage members to the vessel inner wall. These bosses are therefore already present and can be utilised in the present invention. Of course, those skilled in the art will appreciate that other forms of fixing means may be used, the use of threaded bosses applicable here only because they are already present.

To raise the drainage member away the wall 26, longitudinal supporting members 44 are placed in-between the threaded bosses 42 in a longitudinal direction of the vessel. First end 46 of the member 44 includes a half-disc 48 including a half- circle cut out 50. The second end of the member 52 also includes a half disc 48 having a cut out 60 but extending in an opposite direction to the half-disc at end 46.

One can immediately appreciate that as two members 44 are mounted longitudinally their adjoining half-discs define a whole disc with a central aperture defined by cut outs 50 the aperture c-axially aligned with a threaded boss 42.

The discs are of thickness 54 and are attached to the members 44 at their lower surface so that they rise above the members. Typically the discs are welded to the members although they may very well be moulded from suitable materials.

A supporting base 56 extends along the top of the supporting members and includes at one end an aperture 58 c-axially aligned with the threaded boss 42 (and thus with the central aperture of two members 44 defined by the cut outs 50). The other end of the base includes a half-circle cut out or groove 60 whose centre of radius is co-axially aligned with the threaded boss. The cut out 60 is of a size and shape to neatly accommodate a half-disc 48.

If the base 56 is longer than the member 44 the cut out 60 will in fact be another aperture. The illustrations in Figures 3 and 4 are meant to represent the approximate configuration of the clamping means at the end of the vessel. The base is typically some 100 millimetres in width and includes curved edges that ensure that the drainage member does not encounter a sharp drop as it extends over the edges.

A plate 62 extends along the top of the base and includes holes 64 c-axially aligned with the apertures 58 and cut outs 60 of the base and the threaded bosses 42.

Threaded bolts 66 extend through the plate 62, base 56, and engage the threaded bosses 42. Springs 68 extend between the plate and the base to provide a biasing means for the plate against the base. The apertures 58 on the base are countersunk to assist in locating the spring on the base. Typically, the bolts 66 and springs 68 and held captive to the bar 62 using means well known to those skilled in the art to minimise the risk of loose pieces within the press.

Those skilled in the art will immediately appreciate that the biasing means enables the plate and base to move apart without complete disassembly thereby making the placement and removal of the drainage members much easier. Although not shown, the bolts could have an upper stop so that users do not inadvertently completely unscrew the bolts and disassemble the clamping unit. It is however envisaged that users would soon become proficient in the amount of turn necessary for

a bolt to allow for the removal and placement of the drainage members without complete removal of the bolt.

To secure drainage member 34 in-between the plate and the base, its edge is placed on the side of the base 56 and the threaded nuts are screwed into the bosses until the drainage member is firmly clamped as illustrated in Figure 4.

The base 56 is of a convex shape with the outer edge of the base sloping downwardly. The plate includes two downwardly diverging longitudinal shoulders 70 having an edge 72, the edge meeting the drainage member so as to hold it in fixed relative position when the bolts have been rotated to engage the bosses.

Those skilled in the art will readily appreciate that separate drainage members can be positioned in between each clamping means and simply by unscrewing or screwing the bolts, the drainage members may be installed or replaced. In contrast to known prior art where only a faction of the inner wall of the press was used for juice transportation, the present invention provides for a significant increase in the surface area of the draining means leading to much higher juice flows from the press.

There are a typically a plurality of drainage members locked into place between a plurality of clamping means as illustrated in Figure 2. Each drainage member is of the order of 1200 millimeters in width and is generally several meters long, the length dependant on the length of the vessel.

It will also be appreciated by those skilled in the art that alternative orientations of the drainage member 34 are envisaged.

Figure 5 illustrates a typical drainage member 34 suitable for use in a wine press as illustrated above and used to separate juice from a wine mash. The drainage member includes a sieve portion 74 and a support portion 76. The sieve portion 74 and support portion 76 are integrally formed. The sieve portion 74 includes a plurality of spaced longitudinal sieve elements 78. Adjacent sieve elements 78 are separated by a sieve gap 80. Each sieve gap 80 is of a width which is sufficient to allow liquid to pass therethrough and into the support portion 76, while at the same time, preventing solids of a predetermined dimension from passing through the sieve portion 74.

The support portion 76 is formed from a plurality of spaced longitudinal support elements 82. Located between adjacent support elements 82 is a transport path 84.

As the described embodiment relates to the separation of liquid from a solid the transport path 84 will hereinafter be referred to as the fluid path 84.

The support portion 76 supports the sieve portion 74 in manner so that in use a pressure differential exists between an area adjacent to the sieve portion 74 and an area adjacent the support portion. The area adjacent the support portion for this purpose would be equivalent to the fluid path 84. This pressure differential encourages flow through the sieve portion 74 and into the fluid path 84 of the support portion 76.

The sieve elements 78 are arranged so that their longitudinal axes extend substantially parallel to one another. Similarly, the longitudinal axes of each of the support elements 82 are also arranged substantially parallel to one another. However, as illustrated in the Figures, the longitudinal axes of the sieve elements 78 extend substantially perpendicularly to the longitudinal axes of the support elements 82.

Those skilled in the art will appreciate that the angle between the sieve elements 78 and the support elements 82 may not necessarily by a right angle and that other angles may be appropriate under some circumstances provided that sufficient support is provided by the support elements to the sieve elements.

As stated previously, the sieve gap 80 is preferably sized to prevent solids of a predetermined dimension from passing therethrough, whilst still allowing satisfactory flow of liquid into the fluid path 84. When the drainage member 34 is used in applications that involve separating a liquid, such a grape juice, from a mash, the width of the sieve gap 80 is preferably in the order of 1.8 mm. This dimension is sufficient to prevent grape seeds from passing through the sieve portion 74 and into the support portion 76. The width of each fluid path 84 is preferably approximately 7 mm.

When a membrane press may be used for the separation of liquid from solid of other foods, such as pressing for olive oil, the relative dimensions of the drainage member may very well change. However the clamping means need not be modified since the plate will be able to clamp on any drainage member.

As best illustrated in Figures 6 and 7, the top surface 86 of each sieve element 78 and the bottom surface 88 of each support element 82 has a curved profile. The profile is such that the lowermost point of the sieve element and the higher most point of the support element is located substantially midway across the width of the sieve element 78. Typically the sieve elements and the support elements are approximately 3.6 millimetres in height and the radius of curvature is some 4 millimetres.

This curved profile is shaped so that solids in the product that are being sieved tend to be directed towards the top surface 86 of the sieve element 78, in preference to being directed towards and over the sieve gap 80. Effectively, the top surface 86 of the sieve element 78 forms a"cup"for receiving solids such as seeds. As the curved profile extends along the length of the sieve element 78 there is considerable surface area on which solids can be held during a sieving operation. It is desirable to attract solids onto the top surface 86 of the sieve element 78 in preference to being positioned over the sieve gap 80 so that the sieve gap 80 does not become blocked. This ensures that a high level of fluid flow through the sieve gap 80 can be achieved.

Clearly, if the sieve gaps 80 of the sieve portion 74 are covered with solids such as seeds, the rate of flow of liquid through the sieve portion 74 will be dramatically reduced, thereby reducing the effectiveness of the drainage member 34.

The drainage member 34 is preferably made from a food grade plastics material that is flexible. The preferred material is food grade polyvinylchloride.

Although the sieve portion 74 and support portion 76 are described as being integrally formed, it should be understood that this terminology merely indicates that the sieve portion 74 and support portion 76 are joined to form a single member that also defines a fluid transport path. It is not intended to limit the drainage member 34 to a construction made as a single piece.

Typically, the drainage member 34 is made from lengths of extruded plastics material that are welded together to form a grid-like structure. The drainage member may also be made from a plurality of injection moulded drainage pieces that can be connected together to form a drainage member. The drainage member can effectively be any length of a certain width, typically 1.2 metres.

It is envisaged that the drainage member 34 shown in the Figures would have particular application within a membrane press used, for example, to separate grape juice from a grape mash.

Figure 8 illustrates schematically the cross-sectional configuration of a membrane press 10 incorporating a drainage member 34 and clamping means 36 in accordance with an embodiment of the invention. As shown in Figure 8, the membrane press 10 includes a cylindrical vessel 12 divided into two diametrically opposed chambers 16 and 18 by a deformable membrane 20 that is peripherally fixed to the vessel inner wall 26. First chamber 16 of the vessel 12 is arranged to receive a pressurised fluid such as air. Second chamber 18 of the vessel 12 is arranged to receive a product that is to be pressed. The vessel 12 also includes outlets (not shown Figure 8) through which wine juice that has been filtered can be drained from the vessel 12 and an access port (not shown in Figure 8) through which the wine mash is introduced in the membrane press 10.

Figure 8 also illustrates a length of drainage member 34 secured on the inner or hard wall 26 of the vessel 12. The drainage member 34 is mounted in the vessel 12 so that the support portion 76 is located against the wall 26 of the vessel 12 and so that the sieve portion 74 is adjacent to mash. The orientation of the drainage member 34 is such that the longitudinal axes of the support elements 82 extend substantially perpendicularly to the longitudinal axis of the vessel 12. However, other orientations of the drainage member 34 are envisaged.

When pressurised air is applied to the first chamber 16 of the vessel 12, the membrane 20 is caused to expand against the mash in the second chamber 18 of the vessel 12. In this manner, the mash is caused to press against the drainage member 34 so that the drainage member 34 is used to sieve liquid from the mash. It will be appreciated that any liquid within the mash will pass through the various sieve gaps 80 of the drainage member 34 and into the fluid path 84 defined by the support portion 76.

Solids in the mash will be prevented from passing through the sieve portion 74 because of the width of the sieve gaps 80. As explained previously, the configuration of the upper surface 86 of the sieve element 78 will serve to direct seeds and/or other solids within the mash to locate themselves on the upper surface 86 of the sieve element 78, in preference to locating themselves over the sieve gaps 80. To maintain maximum drainage of liquid through the drainage member 34 it is desirable to keep all

of the sieve gaps 80 of the drainage member 34 as clear as possible from solid materials.

Liquid that passes through the sieve gaps 80 flows into the support portion 76.

The liquid passes into the various fluid paths 84 and is directed along the fluid paths 84 towards the fluid outlet 22 by the action of gravity and/or the action of the pressure differential between an area adjacent the sieve portion 74 and an area adjacent the support portion 76.

The drainage member 34 is flexible and light in weight. Accordingly, it will be readily appreciated by those skilled in the art, that it will be possible to bend, flex or roll the sheet of drainage member 34 so that it can be passes with relative ease through the access port 24 of the vessel 12. The flexibility of the drainage member 34 is such that quite a large sheet of drainage member 34 can be elastically deformed so that it can be passed through the access port 24 and once inside, the flexible nature of the drainage member 34 enables it to return to its original shape and to be located against the hard wall 26 of the vessel 12.

It will also be appreciated, that due to the ease in which a sheet of the drainage member 34 can be located within the vessel 12, it is practical to cover the entire hard wall 26 of the vessel 12 with drainage member 34. Before the present invention this was not practical because of the difficulty in positioning a large surface area of a drainage device within the vessel 12 and the resultant time delays.

Prior art drainage devices are very heavy making them extremely difficult to handle and thus the downtime to install them is quite high. Furthermore, they have been difficult to clean and costly to manufacture. Therefore, with prior art drainage devices it has not been practical to cover the entire hard wall of a press with a drainage member and thus, the efficiency of the press has not been maximized. The advantageous nature of a drainage member and press in accordance with an embodiment of the invention means that it is practical to cover the entire hard wall of the press with drainage member 34 thereby maximizing the efficiency of the press.

The flexible and light weight nature of the drainage member 34 is particularly advantageous when it is time to remove the drainage member 34 for cleaning and subsequently when re-locating them within the vessel 12. Ease of removal and

reattachment of the drainage member 34 from the membrane press 10 is particularly important because of the need to regularly clean the drainage members 34 and to avoid unwanted downtime of the membrane press 10.

Although use of the drainage member 34 has been described and illustrated on the hard wall of the vessel 26 only, it is also envisaged that a sheet of drainage member 34 may be applied to the surface of the deformable membrane 20. This would enable liquid coming into contact with the drainage member 34 located on the membrane 20 to also be quickly directed towards the outlet 22. It will be appreciated by those skilled in the art that the liquid has a limited ability to move through the mash and thus the use of a drainage member 34 in this manner will once again increase the efficiency of the press.

It will also be appreciated that a drainage member 34 in accordance with the present invention is easy to cut and requires no special working to fit into a press. This is contrary to prior art steel screens that must be welded punched or bent in order to fit into the press. Accordingly, it will be appreciated that a drainage member in accordance with the present invention is also cheaper and easier to manufacture than prior art devices.

It will be further appreciated that the use of drainage members as herein defined greatly increases the surface area within a press that is used to filter and transport pressed juice form the mash. This is in clear contrast to existing membrane press configurations where the surface area of the drainage members is very limited indeed.

A further important advantage is that the configuration of the present drainage members enables them to be cleaned with relative ease at least when compared to existing drainage members. Further, the drainage members may be easily cleaned with mechanical devices of the type where the drainage members are fed in a continuous fashion. One can also appreciate that due to the elasticity of the drainage members, they can be bent and folded with relative ease. This causes the gaps between the sieve members and the support members to be greatly increased thereby enabling any particles stuck therein between to be removed with relative ease. The saving in time and labour costs is self-obvious.

Although the embodiment described is used to separate a liquid from a solid, the invention is not to be taken to be limited to such an application. The drainage member may adopt numerous different forms and may be used to separate a solid from a solid or a gas from a solid.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.