HK1006009B

HK1006009B - Fluid flow spacing element

Info

Publication number: HK1006009B
Application number: HK98105161.5A
Authority: HK
Inventors: Mohn Jurgen; Heine Wilhelm
Original assignee: Pall Corporation
Priority date: 1987-05-07
Filing date: 1998-06-11
Publication date: 1999-02-05

Description

The invention relates to a spacer element for conducting flow media, in particular in devices for filtering and separating flow media by reverse osmosis and ultrafiltration, each containing a filter element between two essentially disc-shaped spacer elements with a central hole surrounded by the flow medium, the spacer element having a number of spaced openings around the central hole through which the flow medium passes.

A separating element of this type is known (CH-A-577 334). In the case of the device described in this document, the filter elements used are alternately arranged in a cavity for the flux medium, which is formed between two diversion plates. These diversion plates have a central hole, around which a separate disc is placed, which defines an axial distance to the adjacent diversion plate and which is only used to be fixed by means of a thread placed centrally in the diversion plate. At the radial outer edges of each filter element, the otherwise slightly convex formed diversions touch each other, thus causing the current to flow in the direction of the diversion. Due to their shape and the direction of their conversion, a separate disc is placed in the known direction of the diversion plate. The function of the separating element is to prevent the flow from passing through the two filter elements, since they have no function of separation in the direction of the diversion plate.

The disadvantage of the arrangement of the known switch plates in the known device is that additional spacing discs must be provided between two adjacent switch plates, which on the one hand makes the manufacture of such devices considerably complicated and expensive and on the other hand requires a separate housing to ensure the flow of the medium around the filter elements in a chamber or a cavity formed by switch plates and housing.

A spacer element is known from DE-A-19 53 417 with a surface with a ring of bolts that completely encircle the disc, to provide a sufficient seal against liquid escape with a correspondingly high axial force.

US-A-3 398 833 shows a support plate in which the filter elements are unilaterally charged or charged by the flow medium. The raised surfaces formed on the disc element there interact with the outer edge of a hub part to distance a membrane element slightly axially to the adjacent cells, forming a circular space between adjacent cells.

WO-81/01371 is known for a spacer consisting of equal-scale films, preferably of plastic, fitted between adjacent diaphragm cushions, which are bolted on both sides and have breaks, but which do not have any proper stability and are therefore not capable of supporting the filter element.

The present invention is intended to create a spacer element which allows a good flow of the spacer element itself and a filter element on the spacer element, so that even in large stacks of filter elements the partial pressure differences of the flow medium between the inlet and the outlet are kept within reasonable limits and the flow of the flow medium is optimized and the filter element is absorbed at a differential pressure stable.

The problem of the invention is solved by having the filter element shaped like a membrane cushion, by having a projection of a projection of at least one surface of the projection element between two openings spaced apart, and by having a number of projections of heights apart from the surfaces on at least one surface of the projection element and the surface of the projection elements.

The advantage of the spacer element of the invention is essentially that filter elements of the type of a membrane cutter, which do not have any inherent stability, can be used in conjunction with the spacer element and that the spacer element provides for an unimpeded flow of flow media around the filter element, but prevents the direct exposure of the filter element to the surface of the spacer element. The non-self-stable filter elements of the type of a membrane cutter are therefore only on the tip surfaces of the protrusion, with the protrusions on the spacer element in any suitable number and at any appropriate distance, for example, in the case of some partial circular elements, which are intended to be provided by the invention. The function of the special spacer element is not conceivable for the purpose of the membrane cutter.

The openings connecting the two surfaces of the spacer in the central hole area act as effective sieves at a point on the spacer where the flow medium has crossed or encircled the entire surface area of a surface.

The advantage is that the openings are slit-shaped, with the longitudinal sides of the slits, which are longer than their transverse sides, extending essentially radially away from the centre of the hole, thus creating an optimum opening for the flow medium to pass through the area of the openings, with optimum stability of the spacer element, and the advantage is that the openings have a trapezoidal cross-sectional shape.

In order to reduce the swirl in the flow medium in the area of the entrance of the flow medium into the openings, which would inevitably lead to an increase in the partial pressure differences in this area, the spacer element has a thickness that narrows in the direction of the hole in the direction of the opening in the radial direction immediately adjacent to the opening.

In order to allow the permeate, which usually emerges from the permeate outlet holes between the membrane films, to be collected and fed freely into a permeate outlet, the hole of the spacer element is preferably provided at its edge with a number of permeate outlet holes, which can be cleverly formed, which are drawn into a permeate outlet for the permeate, which emerges from the filter element, at a predetermined distance from the centre of the hole, and which is preferably bounded by an outlet on the surface of the spacer element and away from it.

In principle, the seal between the spacer element and the filter element in the area of the front permeate outlet of the filter element can be made in any way, but it is particularly advantageous that around the central hole of the spacer element on both surfaces a circular nutritional depression is formed to accommodate sealing rings, whereby the radial distance of the recesses to the center of the hole is greater than the radial distance between the center and the inner edge of a central hole of the filter element.

The projections themselves may have a essentially circular or essentially droplet-shaped cross-section at a plane parallel to the surface, whereby the droplet-shaped cross-section largely prevents swirling in the flow medium flowing along it and reduces pressure loss.

In order to be able to assemble such filter units into a filter element stack of any size precisely and without any further constructive measures, the spacer element shall, according to another advantageous embodiment, be located in an area immediately surrounding the central hole, on one surface having a plurality of protruding pen-like projections from the central hole and on the other surface having a plurality of projections, each having a projection and a projection in relation to a common central axis obstructing it and having an equal distance to the centre of the hole.

The pen-like projection of a spacer element can thus be inserted into the recess of a neighbouring spacer element, etc., so that an absolutely uniformly aligned filter element stack can be assembled without any effort, preferably with the projections and recesses having the same cross-sectional shape.

The spacer element itself has an outer surrounding edge on both surfaces in the area of its outer circumference, one edge being at least one filter element thickness higher than the other in relation to the surface area normals, so that a filter element (membrane cushion) can be inserted into this depression formed by the slightly higher edge.

The spacer element itself may be made of any suitable material, for example, which gives the spacer element a high strength in light weight.

Preferably the spacer element is made of plastic, preferably ABS, where ABS is particularly suitable in an area where high quality of the permit is required, for example drinking water quality or even pure water quality.

The invention is now described by reference to the following schematic drawings, illustrated by an example of an embodiment, showing: Fig. 1in the section, a device for filtering and separating a flow medium in which a number of spacers and filter elements form a filter element stack,Fig. 2a section of the spacer element along the line A to B of Fig. 6,Fig. 3a section from the representation of Fig. 2 in the enlarged section,Fig. 4a section of the edge area of the spacer element in the area of its central hole in the enlarged section,Fig. 5a section through a drain in the representation of Fig. 4,Fig. 6a view of the spacer element from above - Fig. 7e view from Fig. 6Fig. 9a view from Fig. 8a view from the bottom - Fig. 9a view from the front and back of the section, and a view of the projection and other projection shapes in the section.

For example, a device for filtering and separating flow media by reverse osmosis and ultrafiltration is shown in Figure 1, wherein a number of filter elements 13 and spacer elements 11 are stacked together to form a pre-determined length of filter element stack.

The device 10 is briefly described to help you understand how the spacer element 11 is constructed in conjunction with a filter element 13 in the form of a membrane cushion. The device 10 essentially has a tubular housing 102. In the housing 102 spacer elements 11 and filter elements 13 are alternately inserted, i.e. between each spacer element 11 there is a filter element 13. Only at the ends of the filter element stack thus formed does the filter element 11 not have a filter element 13. At the terminal end of the filter element stack there is a connecting port 105 with a central port 106. The connecting port 105 is a port 105 for the flow of the corresponding current, while the terminal terminal elements 107 and 103 are placed on a central port 106. The connecting port 105 is a port 105 for the flow of the corresponding current, while the terminal elements 107 and 103 are placed on a central port 106. The external port 1010 are connected to the terminal terminal and the terminal are connected to the terminal.

A flow medium 15 entering through the inlet 109 enters the inner chamber of the housing 112 into the gap between the filter element stack and the inner wall of the housing 102 and the flow medium enters the gap between the end-disc 106 and the adjacent spacer element through the openings 14 in the spacer element and flows along the inner surface 119 of the spacer element 11 and then, in the area of the edge 34, around a filter element 13 inserted between the spacer element and the adjacent spacer element 13 and back again towards the centre 14 to re-block the gap by opening the second spacer element 11.From there, the flow of the flux medium is re-directed in the same way to the adjacent spacing elements 11 of the entire filter element stack. From the front sides of the filter element (membrane cushions) directed to the central permeate flow hole or permeate flow channel, the permeate emerges and reaches suitable flow channels, which will be described in detail below, flowing along the central tension bolt 103 outwards from the permeate flow for further processing. The concentrated flow medium 15 arrives, after passing through the entire filter element stack in a quasi-ringed shape, in a moulded assembly area, which is then formed by the 105 outlet flow and is held there for about 110 diels. The filter element is kept inside the entire chamber.

In Fig. 2 a spacer element 11 is shown in the cross section as used in the pre-described filter element stack. In the example described here, the spacer element 11 has a circular cross section and is bounded by two disc-shaped surfaces 118, 119. One axis, symbolized here by the center of the hole 16, is the axis of a central hole 12. Around the center hole 12, the spacer element 11 has a number of spaced openings 14 through the flow medium 15, as described in Fig. 3 and 4, which are described in more detail below. In the example described here, the openings 14 are arranged in a certain linear circle around the center of this hole, at a distance equal to the distance shown in Fig. 6 and 7.

The lengths of the slits are longer than the lengths of the slits 120, 121 and 123. In a radial direction adjacent to the slit 14 and away from the hole 12, the thickness of the spacer element is reduced towards the central hole, which is symbolized by the reference number 17.

Between the spaced openings 14 there is a ledge which is essentially orthogonal to the surfaces 118, 119.

As shown in Fig. 6, the central hole 12 has a number of drainage holes in its peripheral area, these 19 permeate drainage holes protruding into a permeate drainage channel 20 arranged around the centre of the hole 16 at a predetermined distance, see Fig. 3 and 6.

Around the central hole 12 there is a circular nut-like recess 22, 23 on both surfaces 118, 119 which is used to accommodate sealing rings 24, 25, which may be O-rings, for example. These seals 24, 25 are shown in Fig. 3 in the seating position in the nut-like recesses 22, 23.

The filter element 13 in the form of a membrane cushion, which is not shown here in detail in relation to its external shape, has any circular or polygonal outer edge. The filter element 13 is in any case a disc and has such an outer contour that it can be placed on the one surface 118 of the spacer element 11 without closing the area tightly to an edge which delimits the spacer element 11 externally. This allows, as mentioned, the flow medium 15 to be surrounded by the longitudinal currents at filter element 13 and to flow under the filter element at surface 118 along the 14 openings to penetrate through the spacer element 11.

A filter element 13 in Figure 6 is symbolically shown by the dashed line.

The filter element 13 is located with its central hole axially to the hole centre 16 of the spacer element 11, see Figures 7 and 3.

On both surfaces 118, 119 a number of raised projections 29 are arranged from these distant surfaces, as shown in Fig. 6 and 7 symbolically in at least one quadrant by the points on the circles. The projections 29 may be of different shapes, see Fig. 8 and 9. In the representation according to Fig. 8a, 8b, they have a substantially drop-shaped cross-section in a plane parallel to the surfaces 118, 119 which, according to Fig. 8a, may also have a paragraph in its cross-section orthogonal to the surfaces, Fig. 8a. The projection according to Fig. 9a, 9 has a substantially spherical or spherical cross-section in the plane parallel to the surfaces 118, 119 and 29 respectively. It is conceivable that the projection 11 may be used either on a plane or on another element, but it is also conceivable that the projection 29 may be used at a distance of 11 or on another element.

As shown in Figures 6 and 7, the projections 29 are arranged in concentric circles around the centre of the hole 16, but it is also conceivable to arrange them in any other suitable way on surfaces 118, 119.

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Around the area surrounding the central hole 12 a number of these protruding pen-like projections 31 are raised on one of the outer surfaces 118; on the other surface 119 a number of recesses 32 are also provided, each with the projections 31 of a spacer element and a recess 32 in relation to a common central axis 33 intended to pass through them, at an equal distance from the centre of the hole 16; the recesses 31 and 32 of the spacer element generally have the same cross-sectional shape, the upper cross-section being circular in the example shown here.

Each spacer element 11 has an outer surrounding edge 34, 35 to both surfaces 118, 119, where one of the edges 34 is at least one thickness higher than the surface normals of surface 118 and is clearly shown in Figures 2 and 3. In this disc-shaped cavity, as mentioned above, the filter element 13 is inserted, with one surface 130 of the filter element, which is the outer one according to Fig. 3, essentially in the plane with the surface 21. When several spacer elements 11 are joined together to form a top-up filter element stack, as shown in Fig. 1, one filter element 13 is closed between them, with one filter element 13 lying on the front of the filter element 111, while the other filter element 131 lies on the front of the filter element 119, while the other spacer element 1111 lies on the other side of the filter element 119.

As shown at the beginning, the flow medium 15 flows once in a meander on surface 118 towards the openings 14, see Figure 6, is rerouted there and flows away from the openings 14 - side A - on surface 119, see Figure 7 - to be rerouted through the outer closed boundary edges of the filter element (membranes) between the edge 34 of one spacer element and the edge 35 of the other spacer element and flow back towards the openings 14 - side B - of the adjacent spacer element 11.

The filter element 13's membrane films filter or permeate the flow medium 15 and the permeate is created in the space between the two surfaces 130, 131 which, according to the arrow in Figure 3, exits the filter element 13's front side into the permeate flow stream 20 and from there through the permeate flow holes 19 flowing along the tension bolt 103 of Figure 1 and exits the permeate flow 112, 111 appropriately collected.

Due to the high internal pressures in the area between the surfaces of the filter element and the surfaces of the spacer element, a good seal is created between the sealing rings 24, 25 between the filter element 13 and the inner space formed between the spacer element and the filter element, so as to ensure safe separation between the flow medium circuit and the permeate circuit under all operating conditions.

The spacers of the type described herein can preferably be manufactured inexpensively and reliably from plastic, with polystyrene being particularly suitable as a plastic. In particular, acrylonitrile-butadiene-styrene copolymers (ABS), styrene-acrylonitrile-copolymers (SAN) and Luran have been shown to be particularly suitable for the production of spacers because of their acceptability in the drinking water sector.

Bezugszeichenliste
10	Vorrichtung	16	Lochzentrum
102	rohrförmiges Gehäuse	17	Verjüngung
103	zentraler Spannbolzen	18	Steg
104	Mutter	19	Permeatabflußloch
105	Anschlußflansch	19	Permeatabflußloch
106	Endscheibe	20	Permeatabflußrinne
107	Anschlußendlfansch	20	Permeatabflußrinne
108	Endflansch	21	Ansatz
109	Zulauf	22	Vertiefung
110	Ablauf	23	Vertiefung
111	Mutter	24	Dichtungsring
112	Permeatablauf	25	Dichtungsring
113	Dichtung	26	Abstand
118	Oberfläche	27	Abstand
119	Oberfläche	28	Loch
12	Loch	29	Vorsprung
120	Längsseite	30	Stegoberfläche
121	Längsseite	31	Vorsprung
122	Querseite	32	Vertiefung
123	Querseite	33	Achse
13	Filterelement	34	Rand
130	Oberfläche	35	Rand
131	Oberfläche
14	Öffnung
15	Strömungsmedium

Claims

A spacing element for guiding flowing media, particularly in the case of apparatuses for filtering and separating the flowing media by reversal osmosis and ultrafiltration, whereby a filter element is enclosed between two substantially disc-shaped spacing elements (11) which are provided with a central hole (12) and around which flowing medium passes, the spacing element (11) being provided around the central hole (12) with a plurality of apertures (14) spaced apart from one another and through which the flowing medium (15) passes, characterised in that the filter element is constructed in the manner of a diaphragm cushion (13) and in that between any two spaced-apart apertures (14) there is at least one web (18) projecting from a surface (118, 119) of the spacing element and in that on at least one surface (118, 119) of the spacing element (11) and on the surface (30) of the webs (18) there are a plurality of raised projections (29) protruding from the surfaces (118, 119, 30).
A spacing element according to Claim 1, characterised in that the apertures (14) are slit-shaped and the long sides (120, 121) of the slits which are longer than their transverse sides (122, 123) extend substantially radially away from the centre (16) of the hole.
A spacing element according to Claim 2, characterised in that the apertures (14) have a trapezoidal cross-section.
A spacing element according to one or both (sic!) of Claims 1 to 3, characterised in that in the region directed away from the hole (12) and directly adjacent the aperture (14) in a radial direction, the thickness of the spacing element diminishes (17) in the direction of the hole (12).
A spacing element according to one or more of Claims 1 to 4, characterised in that the marginal portion of the hole (12) is provided with a plurality of permeate drains (19) which project into a permeate drain gutter (20) disposed at a predetermined distance from and around the centre (16) of the hole to carry away the permeate emerging from the end of the filter element (13).
A spacing element according to Claim 5, characterised in that the permeate drain channel (20) is bounded by a projecting member (21) constructed on and standing away from the surface (118) of the spacing element (10).
A spacing element according to one or more of Claims 1 to 6, characterised in that around the central hole (12), on both surfaces (118, 119) there is an encircling groove-like depression (22, 23) adapted to receive sealing rings (24, 25), the radial spacing (26) between the depressions (22, 23) and the centre (16) of the hole being greater than the radial spacing (27) between the centre and the inner edge of a central hole (28) in the filter element (13).
A spacing element according to one or more of Claims 1 to 7, characterised in that in a plane parallel with the surfaces (118, 119), the projections (29) have a substantially circular cross-section.
A spacing element according to one or more of Claims 1 to 8, characterised in that in a plane parallel with the surfaces (118, 119) the projections have a substantially drop-shaped cross-section.
A spacing element according to one or more of Claims 1 to 9, characterised in that in the region immediately around the central hole (12), on one surface (118), there are a plurality of peg-like projections (31) standing proud of the said surface while on the other surface (119) there are a plurality of depressions (32), one projection (31) and one depression (32) being spaced at the same distance from the hole centre (16) in respect of an imaginary common central axis (33) passing through them.
A spacing element according to Claim 10, characterised in that the projections (31) and the depressions (32) have an identical cross-sectional shape.
A spacing element according to one or more of Claims 1 to 11, characterised in that it has an outer encircling rim (34, 35) on its two surfaces (118, 119), one of the rims (34) being higher by the thickness of a filter element (13) in respect of the surface normal of the surface (118).
A spacing element according to one or more of Claims 1 to 12, characterised in that it consists of a synthetic plastics material.
A spacing element according to Claim 13, characterised in that the synthetic plastics material is polystyrene.
A spacing element according to Claim 13, characterised in that the synthetic plastics material is acrylonitril butadene styrene copolymer (ABS).
A spacing element according to Claim 13, characterised in that the synthetic plastics material is styrene-acrylonitril-copolymer (SAN).
A spacing element according to Claim 16, characterised in that the synthetic plastics material is lurane.