FILTER PLATE ASSEMBLY

Abstract

A novel embodiment of a Filtration Unit with cleanable permeate side, formed by an internally channeled flat filter plate (1) formed by bonding of two flat half filter plates (2, 3), the filter effect formed by perforation slits or holes (10) in the surface of the plates, said perforations connecting to channels (9) inside the plate. The channels inside the plates are for permeate leading to two or more paired exits (4, 5) perpendicular to the plate, the plate exits forming exit channels for permeate to exit the Filtration Unit. The paired exits makes it possible to clean the permeate site of the Filtration Unit by flushing cleaning media from one exit (4 or 5) to the other exit (4 or 5). The filter area surface (6) can be covered by bonding a fine filter (7), typically an organic flat sheet membrane, to the filter surface, whereby very fine micro or ultra filtration or even molecular filtration can be achieved.

Claims

1. A filter plate assembly (20, 1) comprising at least one filter plate (1) configured for cross-flow filtration, said filter plate comprising a first and a second rigid planar square or rectangular surface enclosing at least two internal permeate channels (9), said first and second surface comprises perforations (10), being in fluid connection with said internal permeate channels (9), characterized in that said filter plate (1) comprises at least a first (4) and a second (5) permeate exit and where each internal permeate channel (9) extends from said first permeate exit (4) to said second permeate exit (5), and said perforations (10) comprise slits or holes, said slits or holes are formed conically with smaller opening to outside the filter plate (1) and widening up towards the internal permeate channels (9).

2. A filter plate assembly (20, 1) according to claim 1, wherein said at least two permeate exits (4,5) extends transversely to said planar surface of said filter plate (1).

3. A filter plate assembly (20, 1) according to one or more of the preceding claims, wherein said filter plate comprises a protrusion, said protrusion constitute said permeate exits (4,5).

4. A filter plate assembly (20, 1) according to one or more of the preceding claims, wherein said filter plate (1) comprises at least one filter (7) sheet positioned bonded adjacent to said first and second perforated outer surface of said filter plate (1).

5. A filter plate assembly (20, 1) according to one or more of the preceding claims, wherein said filter plate (1) comprises two half plates (2,3), which are bonded together at the periphery of the two half plates and said two half plates being identical in shape.

6. A filter plate assembly (20) according to one or more of the preceding claims, wherein said filter plate assembly (20) comprises a plurality of filter plates (1), said filter plates are situated parallel juxtaposed having the perforated surface facing the perforated surface of an adjacent filter plate, said plurality of filter plates forming a square or rectangular entry for a media (A) to be filtered, such that said media (A) is able to pass between the filter plates (1).

7. A filter plate assembly (20) according to claim 6, wherein said filter plate assembly (20) comprises at least two permeate exits, said at least two permeate exits (4,5) of each filter plate combined forms said two combined permeate exit (4,5) extending transversely to said planar surface of said filter plates (1).

8. A filter plate assembly (20) according to claim 6 or 7, wherein said filter plate comprises one or more bonding points (8) for bonding two adjacent filter plates (1), said bonding points together with the protruding permeate exits (4,5) defining the distance between two filter plates (1).

9. A filter plate assembly according to one or more of the preceding claims, wherein said filter plate assembly is composed by a plurality of identically shaped half filter plates (2,3), and where the permeate exits (4,5) are formed by integrated parts of said half filter plates (2,3).

10. Filter plate assembly according to any one or more of the preceding claims, wherein said at least two permeate exits (4,5) are positioned away from each other having said first permeate exit (5) at the entry for a media (A) to be filtered, and having said second permeate exit (4) at the retentate exit (B).

Description

DESCRIPTION OF THE DRAWINGS

[0041] Other features and advantages of the invention is disclosed in the following description, with reference to the accompanying drawings wherein

[0042] FIG. 1 is a perspective view of a filter plate,

[0043] FIG. 2 is an exploded perspective view of a filter plate,

[0044] FIG. 3 is cross-sectional views perpendicular to the longitudinal extension of the filter plate, showing two permeate channels,

[0045] FIG. 4 is a perspective view of a filter plate assembly.

[0046] FIG. 1 Illustrates one embodiment of the Filtration Unit in form of one filter plate (1) formed by a bonding of two half filter plates (2, 3). In the illustrated embodiment, the permeate exit (4, 5) of the Filtration Unit is on either side of the filtration area (6) and the filtration area is not shown with a fine filtering element covering the numerous slit shaped perforations (10). As indicated a number of channels (9) connect the two permeate exits on each filter plate and the perforations lead to the channels. The permeate exits can be sealed off at one side of the unit, depending on need for exit area.

[0047] FIG. 2 Illustrates two half filter plates (2, 3) in an exploded view, showing the inside permeate channels (9) of a filter plate connecting the filter plate exits (4, 5) and also shown are a variation in layout of inside channels. The channels (9) may be joined in a manifold like channel before connecting to the larger exit holes (4, 5). The exit holes can be placed as convenient, for example in opposite corners or side by side, considering short and efficient drainage channels (9) for the permeate. In a larger plate, more paired exits may be needed to secure drainage as well as cleaning of the permeate side.

[0048] The filter plate (1) comprises bonding points (8), the bonding points also functioning as distance point together with the protruding permeate exits, such that the media to be filtered can pass the filter plate assembly (20) in-between two adjacent filter plates (1). In FIG. 2 is illustrated four bonding points (8), and they are positioned at the periphery of the filter plate to avoid obstruction of the media to pass the filter plate assembly (20).

[0049] The bonding points (8) are illustrated as a solid cylinder shaped protrusion extending transversely to the surface of the filter plates (1). Alternative the distance between plates can be supported by a mechanical member positioned at the edge of the filter plate assembly.

[0050] FIG. 3 Illustrates details of a filter plate with example of the conical perforation (10) of the filter plates leading to permeate channels (9) in the filter plate and (E) illustrates bonding area of half filter plates (2, 3) and (F) bonding areas of fine filter cloth (7) on both side to filter plate. In the figure the two half plates (2,3) are bonded at the periphery (E). Also shown are an example of a filter plate made up by two not identical half filter plates, where the channels are predominantly formed in one half. The bonding (E) of the two half plats must secure a complete sealing of the inside of the bonded filter plates all along the edge, so that filtrate only enters the permeate side at designated filtration area. To ensure rigid filter plates, the filter plates may be bonded at various points within plate area, when two half filter plates (2, 3) are bonded into one filter plate (1).

[0051] The filter (7) is bonded to the surface of a half plate (F). The bonding (F) of the fine filter, when this is relevant for the application of the Filtration Unit, on the two sides of the filter plats, must likewise secure a complete sealing of the inside of the bonded filter plate all along the edge, so that filtrate only enters the permeate side at designated filtration area. To ensure rigid fixation of the fine filter to the filter plates, the fine filter may be bonded at various points within edge, as this will allow for trouble free back washing or back flushing of the fine filter.

[0052] Experiments have shown that a filter plate made by injection molding in plastic of 2 half plates of 2 mm plate thickness and with 2 mm permeate channels give a good rigid structure for 20 cm wide an 90 cm long filter plate and that slits of 0.1 mm by 5 mm that are spaced 5 mm sideways and longitudinal to permeate channel give good drain ability to open microfiltration organic membrane and good support to withstand a high trans membrane pressure of more than 10 bar when needed.

[0053] FIG. 4 shows a stack of filter plates formed into a multi plate filtration unit (20) and the flows of filtrate/retentate (A, B) and permeate (C, D). Retentate is the term used for media to be filtered, this can be in form of a liquid stream entering (A) and exiting (B) the filter area in the Filtration Unit in a continuously flowing stream when Filtration Unit is used in a cross flow mode. In the illustration two permeate exits are shown and during CIP cleaningCleaning In Placecleaning media can enter one permeate exit and exit the other, thereby cleaning the permeate side of the Filtration Unit.

[0054] The filter plate assembly (20,1) (also called Filtration Unit) comprises filter plates (1). The filter plate assembly comprises a plurality of filter plates (1), said filter plates situated parallel juxtaposed having the perforated surface facing the perforated surface of an adjacent filter plate (1), two adjacent filter plates having a distance of 1 to 6 mm such that said media (A) is able to pass the filter plate assembly (20) between the filter plates (1). The plurality of filter plates (1) forms a square or rectangle entry for the media (A) to be filtered.

[0055] The filter plate assembly (20,1) comprises two permeate exits. The cylindrical protrusions (4,5) (as shown in FIGS. 1 and 2) of each filter plate combined forms said two combined permeate exit (4,5) extending transversely to the extension of the planar surface of the filter plates (1).

[0056] It goes without saying that different modifications may be made to the examples described, without departing from the scope and spirit of the invention.

[0057] Further embodiments are disclosed in the following.

[0058] A sanitary Filtration Unit cleanable on the permeate side, formed by a flat elongate rigid filter plate (1) being composed of two half plates (2, 3) bonded at least around edge in a way whereby sealing (E) is secured, the half plates being of substantially identical perforated surfaces on outside, and with a thickness giving room for internal channels (9) in parallel to the flat surface for unimpeded, channeled draining of permeated media entered through the plural of perforations (10), said channels leading to paired exits (4, 5) perpendicular to filter plate surface so that these form the exit channels for permeated media from the stacked Filtration Unit. The permeate channels (9) and hence the permeate or back side of the filter areas in the filter plate can be flushed through during cleaning by entering cleaning media in one of paired exits (for example (4)) and exit the Filtration Unit through the other of the paired exits (for example (5)).

[0059] The bonded filter plate shall have a structure to form a sufficient rigid structure of the Filtration Unit providing good dimensional stability under mechanical, thermal and chemical stress.

[0060] The Filtration Unit to be used for finer filtration than the filtration offered by the perforations in the filter plates through an added fine filter (7) covering the filter area (6) and where the perforations (10) and the filter plats (1) offer drainage for the fine filter and so the Filtration Unit acts as collector and support for the fine filter, said fine filter being as example a fine mesh sheet or membrane suitable for Micro, Ultra, Nano filtration or Reverse Osmosis filtration, said fine filter bonded to the filter plate fully covering the perforated filter area (6) in a way whereby sealing is secured at the edge. The fine filter (7) is bonded in numerous spots or lines to the filter plate (1) whereby a back flow of filtered permeate can wash the active filter area without damaging the fine filter, and whereby longer filtration time before need for cleaning can be achieved. The fine filter (7) is compounded on the filtration plate either as a membrane formed by spheres or fibers or woven material or molded as an organic membrane or combination of these thereby creating the Micro, Ultra, Nano filtration or Reverse Osmosis filtration, and where the filter plate (1) acts as collector and support for the fine filter (7).

[0061] The rigid structure allows for the Filtration Unit to be exposed to a mechanical movement parallel to the filter plate and hence filter surface and to the media to be filtered, keeping the filter surface clean and secure lower the concentration gradient of media close to the filter surface, thereby increasing flux of permeate per square meter filter area and keep the filter operational for longer time.

[0062] The filter plate (1) is between 2 and 6 mm thick comprised by two half plates (3, 4) typically molded in plastics or other media withstanding and rigid material and with dimensions giving room for a filtration area from some 10's of square centimeter to some 10's of square decimeter and with and with internal channels for filtered media roughly half the thickness of the filter plate and with numerous conical filtration perforations as slits or holes connecting filter plate surface and the internal channels with perforation openings of 0.05 to 0.50 mm at the surface, said internal channels leading to filter plate exits (4, 5) of typically a diameter of 10 to 50 mm.

[0063] The filter plate (1) is stacked and bonded into a unit where the number of stacked filter plates typically compile to form a square size Filtration Unit seen from entry and exit side of flow direction, the opening and free passage for media to be filtered is between 1 and 6 mm between opposite arranged filter plates. It shall be noted that the overall design hereby gives possibility to have many square meters of filtration area in one compact Filtration Unit.

[0064] The half plates (2, 3) bonding into edge-wise sealed filter plates and the bonding of edge-wise sealed fine filter (7) onto filter plates (1) and the sealing bonding of filter plate exit to filter plate exit (4, 5) or the bonding of bonding points (8), said bonding can be through direct or indirect or laser or ultrasonic or otherwise applied heat for re-melting material of said parts or for melting added material or for a media to dissolve material or to add glue or to add mechanical fixtures or combination of above to perform a strong bond of the assemblies or subassemblies together forming the Filtration Unit

[0065] All parts can be of food and pharmaceutical grade material with traceable origins, making the Filtration Unit suitable for human food consumables and the likes. The materials used are preferably of a plastic material that can be reused by re-melting or burned as a clean fossil-like fuel.

[0066] The parts of the unit are produced by 3 D printing or sintering of other means.