FILTER PLATE ASSEMBLY

Abstract

A novel embodiment of a Free Flow Filtration Unit ensuring unimpeded flow of media to be filtered and unimpeded flow of permeated media in a leakage proof fully fused rigid unit. A Filtration Unit fused into a singular element, formed by a fused stack of internally channeled flat filter plates (1) each plate formed by fusing of two molded 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) in the plates for free flow of permeate (filtered media) leading to one or more exit (4) perpendicular to the plate, the filter plate exits forming exit channels for permeate from the Filtration Unit as the filter plates (1) are fused into a stack at the exit (4) and at bonding points (8) securing that the filter plates are spaced and rigidly fixed at specific distance in the stack, offering slit like gaps at least at 2 sides for free access and exit flow of media to be filtered. The filter area surface (6) can be covered by fusing a fine filter (7), typically an organic flat sheet membrane, to the filter area surface, whereby very fine micro or ultra-filtration or even molecular filtration can be achieved.

Claims

1. A filter plate assembly (20,1) configured for cross-flow filtration, said filter plate assembly comprises a plurality of plastic molded planar square or rectangular filter plates (1) and one or more permeate exits (4,5), said filter plates (1) comprises a first and a second rigid surface, said surfaces comprise perforations (10), said surfaces enclosing a volume, said volume constitute one or more permeate channels (9), whereby said perforations (10) are fluidly connected to said one or more permeate exit (4,5) through said permeate channels (9), characterized in that said filter plates comprises a protrusion, said protrusions of said plurality of filter plates combined forms said permeate exits (4,5) from the filter plate assembly.

2. A filter plate assembly (20,1) according to claim 1, wherein one or more of said filter plates (1) comprises two half filter plates (2,3), said half filter plates (2,3) are bonded together at the periphery of the filter plates.

3. A filter plate assembly (20,1) according to claim 2, wherein said half filter plates (2,3) being identical in shape.

4. A filter plate assembly (20,1) according to claim 1, wherein said one or more permeate exits (4,5) extends perpendicular to the plane defined by the extent of said filter plates (1).

5. A filter plate assembly (20,1) according to claim 1, wherein said filter plates (1) comprising an additional filter sheet (7) positioned and bonded adjacent to said perforated surface of said filter plates (1).

6. A filter plate assembly (20,1) according to claim 1, wherein said filter plate (10) comprises bonding points (8) for bonding two adjacent filter plates (1), said bonding points together with the protruding exits (4,5) defining the distance between two juxtaposed filter plates (1), and said filter plate assembly (20) forms a rigid singular assembly through fusing of said bonding points (8) and protruding exits (4,5).

7. A filter plate assembly according to claim 1, wherein said filter plate assembly (20) comprises actuation means for mechanical actuation such as movement or vibration of said filter plate assembly in a plane parallel to the extent of said filter plates (1).

8. A filter plate assembly (20) according to claim 1, wherein said filter plate assembly (20) comprises a plurality of filter plates (1) and a housing (30), said filter plates are situated parallel juxtaposed having the perforated surface facing the perforated surface of an adjacent filter plate, said housing encompassing said plurality of filter plates (1) forming a square or rectangular entry for a media (A) to be filtered and a retentate exit (B).

Description

DESCRIPTION OF THE DRAWINGS

[0052] Other features and advantages of the invention is disclosed in the following description, with reference to the accompanying drawings wherein

[0053] FIG. 1 is a perspective view of a filter plate assembly,

[0054] FIG. 2 is a perspective view of a filter plate assembly,

[0055] FIG. 3 is an exploded perspective view of filter plates,

[0056] FIG. 4 shows cross-sectional views perpendicular to the longitudinal extension of the filter plates,

[0057] FIG. 5 is a side view and a perspective view of a filter plate assembly,

[0058] FIG. 6 is a perspective view of a filter plate assembly comprising a housing.

[0059] FIG. 1 illustrates one embodiment of the Filtration Unit formed by a fused stack of filter plates (1). In the illustrated embodiment, the permeate exit(4) of the Filtration Unit is at the end of the filtration area (6) and the filtration area is shown without a fine filtering element covering the numerous slit shaped perforations (10). As indicated a number of channels (9) connect to the permeate exit inside the filter plate and the perforations lead to these channels. The permeate exit from the unit can be sealed off at one side of the stack, depending on need for exit area. The slit or gap between filter plates, form the free entry area for media to be filtered.

[0060] FIG. 2 shows the flows of filtrate/retentate (A, B) and permeate (C). 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.

[0061] FIG. 3 illustrates two half filter plates (2, 3) in an exploded view, showing the inside channels (9) of a filter plate connecting the inside permeate channels to the filter plate exits (4) and also shown are variations 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) or be formed as an open grid like channel formed by the two half plates where these meet. The exit hole or 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.

[0062] FIG. 4 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 fusing area of half filter plates (2, 3) and (F) fusing areas of an additional filter sheet (7), such as a fine filter cloth or organic filter membrane on both side to filter plate as well as example of pressure loss reducing edge of filter plate. 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.

[0063] The fusing (E) of the two half plats must secure a complete sealing of the inside of the fused 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 fused at various points within plate area, when two half filter plates (2, 3) are fused into one filter plate (1).

[0064] The edges of the filter plates (1) are streamlined to reduce resistance.

[0065] The fine filter cloth adding an additional filtration of a filter plate.

[0066] The fusing (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 fused filter plates 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 fused at various points or lines within edge, as this will allow for trouble free back washing or back flushing of the fine filter.

[0067] 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.

[0068] FIG. 5 illustrates two variations of a plural of filter plates fused into a stack, thereby forming a compounded Filtration Unit, and also showing a rigid structure achieved through the bonding points (8) and the fusing of permeate studs (4, 5). The fusing of the permeate studs must ensure a complete sealing of inside of the Filtration Unit, as filtrate must only enter the permeate side at the filtration areas. The number of and size of bonding points is adapted to the dimensions of the filtration plates and size of unit ensuring that sufficient structure is in place to secure a sufficiently rigid and strong Filtration Unit. Experiments have shown that 4 of 5 mm bonding points in each corner will give a sufficient rigid support to a 20 cm by 20 cm filtration area, given that the filter plate is a 4 mm thick assembly of stiff polymeric plastic and that the permeate exits are rigidly fused and close to the filtration area. Similar strength is achieved when bonding points are in form of a Bonding Point Bar (8a) fused at various points to the side of the filter plates securing uniform spacing and rigid structure of the element.

[0069] FIG. 5 shows a filter plate assembly, wherein said filter plate assembly forms a rigid singular assembly through fusing of bonding points (8) and protruding exits (4,5).

[0070] The filter plates (1) comprise a first and a second rigid surface, said surfaces also called filter areas (6), which comprise perforations (10).

[0071] The additional filter sheet (7) is sufficiently bonded to said perforated surface (10) of the filter plates (1) with sufficient distance between filter plates (1) to allow for back flow of permeate through the filter membrane (7) without filter membranes colliding through ballooning of said filter membrane.

[0072] Hereby further improvement of filtration and increase in flux of permeate per filter area is possible through possible back flush or movement of the filter assembly.

[0073] The filter plate assembly forms an open rigid free flow structure allowing for mechanical actuation or vibration of the filter plate assembly parallel to the filter plates while the free access allow for movement of media to be filtered in relation to the filter plates (1).

[0074] FIG. 6 illustrates two Filtration Units in series placed in a pressure withstanding flow channel, where inspection of filter surface is possible through a look through glass, and where a cross flow stream can enter in one end and exit in the other end of the series mounted Filtration Units and where permeate can exit the side of the channel.

[0075] It goes without saying that different modifications may be made to the examples described, without departing from the scope and spirit of the invention.

[0076] Further embodiments are disclosed in the following.

[0077] A Filtration Unit in form of a compounded singular element, formed by a fused, rigid stack of internally channeled rectangular like, flat filter plates (1), each plate formed by fusing of two molded flat half filter plates (2, 3), fused together at least around edge in a way whereby sealing (E) is secured, the half plates being with substantially identical filtration areas (6) with a plural of perforation slits or holes (10), and with a thickness giving room for internal channels (9) where the half plates meet for unimpeded draining of permeated media entered through the perforations (10), said internal channels (9) leading to one or more filter plate exits (4, 5) with raised neck bracing perpendicular to filter plate surface, the filter plate exits forming exit channels for permeate from the compounded element forming the Filtration Unit as several filter plates (1) are fused together, in a way whereby sealing is secured, into a stack at the raised exits (4, 5) and at bonding points (8) securing that the filter plates are spaced and rigidly fixed at specific distance in the stack, offering slit like gaps at least at 2 sides for free access and exit flow of media to be filtered. The fused stack of filter plates forming the Filtration Unit shall form a sufficient rigid structure providing good dimensional stability under mechanical, thermal and chemical stress.

[0078] The filtration can be obtained through an added fine filter sheet (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 fused to the filter plate fully covering the perforated filter area (6) in a way whereby sealing is secured at the edge.

[0079] The fine filter (7) is fused 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.

[0080] The Filtration Unit comprises a housing (30) having at least one see through part, such as a window, giving access to visual observation of filtration area (6) and all other parts and details (for example through look through glass close to Filtration Unit if this is placed in a channel) as well as good access for flow of cleaning media to all surfaces, this being possible through the rigid structure and free spacing between the stacked and fused filter plates.

[0081] The edges of the filter plates are formed with a hydro dynamically shaped gradient to minimize pressure loss of flow entering or exiting the free passage over filtration area through the slit like gaps between filter plates and where the flat surface of the filter area (6) is corrugated to increase turbulence of media to be filtered over filtration area.

[0082] The filter plates (1) are stacked and fused 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 and where each filter plate 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 internal channels or free area for permeated media up to 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. It shall be noted that the overall design hereby gives possibility to have many square meters of filtration area in one compact Filtration Unit.

[0083] The half plates (2, 3) fusing into edge-wise sealed filter plates and the fusing of edge-wise sealed fine filter (7) onto filter plates (1) and the edge-wise sealed fusing of filter plate exit to filter plate exit (4, 5) or the fusing of bonding points (8), said fusing 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 weld or fused bond of the assemblies and subassemblies together forming the Filtration Unit

[0084] The filter plates (1) are positioned in parallel or in series in a suitable pressure withstanding flow channel, wherein the filter areas are flushed over by media to be filtered in a cross flow created by a fast moving flow, flowing through the Filtration Unit via the slit like gaps, and where the permeate exits the Filtration Unit exit (4, 5) out through the side of the pressure withstanding flow channel in suitably dimensioned and sealed permeate exit connections.

[0085] The rigid fused structure allows for the Filtration Unit by itself or when fixed in a flow channel, to be exposed to a mechanical movement parallel to the filter plates and hence filter surface and to the flow of 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.

[0086] 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.

[0087] The parts of the unit are produced by 3 D printing or sintering of other means.