Title of Invention

MEMBRANE FILTER PRESS WITH AT LEAST ONE MEMBRANE FILTER PLATE

Abstract

The invention relates to a membrane filter press. On operation of such a press a secure generation of the necessary pressing pressure can be guaranteed with a membrane filter press comprising at least one membrane filter plate (1), a baseplate (3) with thickened edge region (4), a membrane (6) made from an elastically-deformable material and a filter cloth (7), whereby the membrane (6) comprises an annular edge beading (9) which lies in a complementary groove (8) on the baseplate. A sealing groove (29) is also let into the baseplate which opens out into the groove (8) at both ends in the manner of a bypass. A complementary sealing projection (30), moulded on the annular beading, engages in the sealing groove with formation of a seal. The cavity enclosed between the groove and the sealing groove is preferably provided with at least one filtrate drain drilling (23).

Full Text

Description Membrane filter press The invention relates to a membrane filter press which comprises in a known way a plurality of membrane filter plates and membrane-free filter plates arranged between them. In the operating state, the filter plates are tension-mounted between a head piece and an end piece and are configured in such a way that a filter space is arranged between them. Those faces of the filter plates which delimit the filter space are equipped with bbsses or grooves and are covered with a filter cloth. The bossed or grooved surface is formed, in the membrane filter plates, by a t flexible or elastically deformable membrane consisting of rubber or plastic. The rear side of the membrane can be acted upon with a pressure medium in order to remove the residual moisture of a filter cake formed in the filter space during filtration. When the membrane rear side "is acred upon by pressure with a pressure medium, an insufficient build-up of pressure force may occur, for example, because a pressure space i*s* leaky due to material fatigue. If pressure medium can escape from the pressure space, effective pressure filtration is no longer possible on account of the lower pressure force. Moreover, tr.is may lead to a contamination cf the filtrate by the pressure medium. Proceeding from this, the object of the inventicr., in a membrane filter press, is to ensure a reliable build-up of the required pressure force. This ob:ect is achieved by means of a membrane filter press having the features of claim 1. Accordingly, a membrane filter press is proposed, which comprises at least one membrane filter plate, a baseplate with a thickened edge region, a membrane consisting of an elastically deformable material and a filter cloth, the membrane having an edge-standing ^annular bead seated in a complementarily configured groove of the baseplate. At the same time, the baseplate has introduced in it a sealing groove which issues into the groove at both ends in the manner of a bypass. A complementarily configured sealing projection integrally formed onto the annular bead engages sealingly into the sealing groove. Since the membrane is seated with a sealing projection in said sealing groove, the membrane is prevented from lifting off from the baseplate as a result of the action of pressure upon the rear side of the membrane. The pressure medium cannot flow cut via the filtrate run-off bore at the parting plane between the membrane inside and the baseplate, but, instead, remains reliably in the pressure space. A reduction in the pressure force on the membrane is thereby ruled out. The required pressure force can be built up reliably. At the same time, by the pressure space being sealed off, a contamination of the filtrate with pressure medium is prevented. In an embodiment of the invention as claimed in claim . „ 2, there is in the baseplate, between the groove and the sealing groove, at least one filtrate run-off bore which is connected to a bore passing through the membrane and likewise serves for discharging the filtrate. This ensures a reliable filtrate run-off. At the same time, this measure provides a sealing off of the filtrate run-off bore. According to the teaching of claim 3, the membrane has an edge-standing annular bead of essentially dovetail-shaped cross section, which is seated in a complementarily configured groove arranged in the baseplate. The same applies to the interaction of sealing projection and sealing groove. The dovetail shape aerie^es particularly reliable sealing off. Moreover, ir filter presses of the type mentioned, .the fixing cf :r.e filter cloth in the case of a driptight version preserts problems. It is known, for example, to lead the filter cloth outward between two filter plates bearing against one another, said filter cloth serving for sealing cff the parting plane present between the filter plates. The two filter cloths assigned to a filter plate are often connected to one another with their edges lying outside the filter plates by means of loops or a touch-and-close fastening. Such c design is unfavorable not only because of the lack of driptighttess, but also from a hygienic point of view. To 3pe precise, microorganisms may enter the filter press ri a the filter cloths. In other press versions, the filter cloth is fastened to that edge of the membrane filter plate which is outwardly, adjacent to the membrane. This has the advantage, inter alia, that, because :f the space requirement necessary for this - purpose, the filtration area of the filter plate is reduced. Mcreever, this type ■ of cloth fastening requires ?.:.■ :t.leased outlay in assembly terms. For tr.re reason, in a particularly advantageous embodiment c f the invention as claimed in claim 4, a membrane _ s ;: reposed, in the annular bead of which is arranged a ferine groove in which a fixing strip is seated. fee 1-lter el cm is en this case fixed indirectly ;r directly with its edge region to this fixing strip . the fastening of the membrane arid"~cf "the filter el : ;:. are. thereby interlinked, thus reducing the number c: par:= necessary for fixing. This, however, also make; ::■: en ting and demounting easier. Furthermore, this type :i cloth fixing does not need any space requirement in the plate edge region. Consequently, a larger memierare with a correspondingly larger useful filtration area can be employed and the filtration capacity increased. A penetration of hygienically harmful germs via the filter cloth is prevented. As a result of this cloth fastening, the membrane filter plate is improved, particularly with regard to the number of parts and to the outlay in terms of mounting and demounting. A form fit between fixing groove and fixing strip (claim 5), said form fit being effective transversely with respect to the plane of the baseplate, is expedient, because this ensures a particularly reliable cloth fixing which, in particular, is effective even in the opened state of the filter press. In this respect, a force fit between said parts also takes effect, for example due to restoring forces as result of widening of the fixing groove by the fixing strip (claim 6) . Hermetic sealing off, preventing the penetration of microorganisms, is thereby also achieved. Furthermore, the annular bead of the membrane is .keyed in the dovetail-shaped groove of the baseplate and the clamping action of the fixing strip holding the filter cloth is increased. At the same time, a sealing off preventing the penetration of microorganisms occurs in the fixing region and is essential particularly when a filter press is employed for the production of foodstuffs, pharmaceutical products or toxic suDSudnccs . In a f urt.ter exemplary embodiment of the invention as claimed in claim 7, rhe fixing region in question is preferably configured in such a way that the fixing strip and the filter clcth dc not project, in the region of rhe membrane bead, beyond the plane scanned by the edge region of the baseplate. This ensures that the filter cloth and filter strip do not impede the bearing of- filter plates against one another in their edge region, so that a mutual hermetic sealing off of the filrer plates, for example by a sealing ring being interposed, is possible in a simple way. The measure which is shown in the exemplary embodiment taught in claim 8 and whereby the fixing strip fills the fixing groove essentially completely is aimed at avoiding gap spaces capable of being contaminated with microorganisms - As already mentioned above, the outward sealing off of the filter press takes place in the region of the edge region of the filter plates. Preferably, then, the membrane bead is provided with a sealing lip which surrounds the fixing groove, that is to say lies radially outside the fixing groove, and which projects beyond the plane spanned by the baseplate edge region (claim 9). The sealing lip can therefore cooperate with a counterplate with the effect of a hermetic sealing off. Additional structural measures, such as the introduction of a sealing groove into the filter plate and the insertion of a sealing cord, may therefore be dispensed with. The annular bead'of the membrane thus has a threefold function: it serves for fastening the membrane and at the- same time -he filter cloth and, furthermore, ensures .that the filter chamber and the space behind the membranes are sealed off outwardly. The number of parts necessary for a membrane filter plate is thereby further reduced. The outlay in terms of production and the outlay in terms of the. mounting and demounting of the filter cloth and the membrane are correspondingly low. Claims 1C tc 13 relate to further exemplary embodiments of the invention with various possibilities for fixing the filter cloth. The invention then, is explained in more detail with reference tc exemplary embodiments illustrated in the accompanying drawings in which: fig. 1 shows the top view of the corner region of a membrane filter plate with the membrane removed,* fig. 2 shows a cross section according to the line II-II in fig. 1, fig. 3 shows a cross-sectional illustration corresponding to fig. 2, which shows the corner region of a membrane plate and of a membrane-free intermediate plate, fig. 4 shows the detail IV from fig. 3, fig. 5 shows the detail V from fig. 3, fig. 6 shows the detail VI from fig. 3, and fig. 7 shows the top view of a differently configured membrane plate with a membrane fastened to it. A filter press of the type in question is composed essentially of a plurality of membrane filter plates 1 and of. membrane-free intermediate plates 2 arranged in each case between two membrane filter plates. As is evident particularly from figs. 1-3, a membrane filter plate 1 comprises a baseplate 3 with a thickened edge region 4, a membrane 6 fixed to the baseplate 3 and having bosses 5 on its outside and a filter cloth 7. The intermediate plates 2 likewise have a thickened edge region 4a. In the operating state, said plates are tension-mounted between a head piece and an end piece (not illustrated) , and they bear with trveir edge regions 4, 4a against or.e another. The plate regions adjoining the edge region 4, 4a radially inward are drawn inward, so that a filter space 11 (fig. 3) is formed between two plates cooperating with one another. To fix the membrane 6 to the baseplate 3, a reception recess or groove 8 of dovetail-shaped cross section is arranged in the edge region 4 of said baseplate. The groove 8 extends in the circumferential- direction over the entire edge region, that is to say has an annular design. The membrane 6 has an edge-standing annular bead 9 which has a cross-sectional shape corresponding essentially to the groove 8 and which is seated with a form fit in the groove 8. The insertion of the membrane* 6 into the groove 8 in this case takes place with elastic deformation of the membrane 6 consisting of a rubber-like or elastic plastic. The restoring forces caused thereby bring about a force fit between the annular bead 9 and groove 8. A fixing groove 10 is introduced into the annular bead 9 from the outside, carrying the bosses 5, of the membrane 6 and widens toward its groove bottom. This widening may be such that the groove walls 12 first run parallel to one another and then merge into a portion 13 of approximately circular cross section. In the fixing groove 10 is seated a fixing strip 14 which has a cross-sectional shape corresponding to the groove cross section. The cross-sectional dimensions of the fixing strip are in this case such that they are seated in the fixing groove 10, with the annular bead 9 being widened elastically. The strength of the connection between the membrane 6 and the baseplate 3, on the one hand, and between the fixing strip 14 and the fixing groove 10, on the other hand, is thereby increased. The filter cloth 7' is fixed to the fixing strip 14, so that the strength of the connection between the filter cloth 7 and membrane 6 is also increased in the way outlined. The fixing strip 14 fills the fixing groove 10 essentially completely, thus avoiding saps or dead spaces which entail the risk of the accumulation of dirt and microorganisms. The filter cloth 7 and fixing strip 14 are arranged in such a way that, in the closed state of the filter press, they initially do not project beyond the plane 15 spanned by the edge region 4 of the baseplate. This ensures that only the edge region 4 takes over the mutual planar bearing contact cf the filter plates and assumes a sealing-off function possibly necessary there. The sealing-off function between the filter plates* Bearing against one another is assumed by the annular bead 9, so that additional sealing-off measures, that is to say grooves in the edge region and corresponding sealing rings, may be dispensed with. For this purpose, the radially outer wall 16 of the annular bead 9 is prolonged into a sealing lip 17 which projects beyond the plane 15. In the operating state, the sealing lip 17 stands against the edge region of a counterplate, for example an intermediate plate 2, and forms a structurally simple and efficient sealing off of the membrane filter press. The filter cloth 7 may be fixed to the fixing strip 14 in various ways. In the exemplary embodiment according to fig. 4, the top side, covering the fixing groove 10, of the fixing strip 14 seated with elastic widening in the fixing groove 10 forms an adhesive face 18 tc which the filter cloth 7 is glued with its edge, region. The connection between the filter cloth 7 and adhesive face 18 may, however, also oe carried out by means of welding, for example when the two parts consist of plastics capable of being welded to one another. In the type of fastening illustrated in fig. 5, the filter cloth 7 is inserted between the fixing strip 14 and the wall of me fixing grove 10. The fixing strip 14 is dimensioned such that the annular bead 9 is widened radially and, correspondingly, both the filter cloth 7 and the fixing strip 14 are clamped in the fixing groove by means cf the restoring forces cf the annular oead material. Furthermore, the top side 19 of the fixing strip 14 is arranged in the plane 15. The edge space 2 0 cf the filter cloth 7 seated in the fixing groove II is likewise flush with the plane 15. A relatively planar sheetlike arrangement essentially free of gaps is thereby provided in the region of the annular bead 9. In order to ensure a filtrate run-off, the membrane 6 has a plurality of bores 22 which are arranged near the annular bead 9 and which are in alignment with or fluidicaily connected to a filtrate run-off bore 23 passing transversely through the baseplate 3. The filtrate run-off bore 23 is itself connected via a connecting bore 24 to a filtrate duct 25 (figs. 1 and 2) arranged in the corner region of the baseplate 3. The filtrate accumulating between the filter cloth 7 and the membrane 6 or between the bosses 5 of the latter can therefore flow off in the direction of the arrow 26 via said bores. In order to ensure that the pressure space 27 present between the membrane 6 and the inwardly drawn baseplate region 28 and capable of being acted upon with pressure to press out a filter cake is sealed off with respect to the filtrate run-off bore, two sealing grooves 29, 2 9a of dovetail-shaped cross section are introduced in the edge region of the baseplate 2. The sealing grooves 29, 29a are in this case arranged in an inner region of the baseplate 3, said inner region being bordered by the groove S. The sealing grooves issue into the groove 6 in each case at both ends in the manner of a bypass. A sealing projection 30 configured complementarily in cross section and integrally formed onto the annular bead 9 is seated in each of the sealing grooves 29, 29a with a form fit and preferably under elastic prestress. The design outlined prevents the membrane from lifting off from the baseplate surface in the direction of, the arrow 32 figs. 3 and 4' when pressure acts upon the pressure space 27, with the result that pressure medium may enter the filtrate run-off bore 23 via the gap space present between the membrane 6 and baseplate 3, which would impede the build-up of a required pressure force and, moreover, lead to pressure medium entering the filtrate. In the membrane filter plate la illustrated in fig. 7, with a membrane 6 fixed to it, the just outlined additional sealing off of the bores 22a is absent. Here, the membrane is prevented from lifting off in the event of the action of pressure upon its rear side by a pressure medium, in that the membrane is supported on a counterplate, that is to say, for example, an intermediate plate 2, by means of supporting bosses 31 in the region assigned to the bores 22a. That edge region of the baseplate 3 which surrounds the filtrate run-off duct 25 has an annular groove 33 of dovetail-shaped cross section in which a sealing ring 34 for sealing off the filtrate run-off duct 25 is seated. The intermediate plate 2 has introduced in it on both sides grooves 35 which are configured similarly to the fixing groove 10 of.the membrane filter plates 1 and in" which clamping strips 36 of essentially circular cross section are seated, with the filter cloth 7a being interposed. The end of the filter cloth 7 a is sewn together to form a hemstitch 37 which surrounds the clamping strip 36. Such a design is also possible with reg„ard tc the fixing strip 14 and to the filter cloth 7 of the membrane filter plate 1. The depth of the groove 35, the cross-sectional dimensions of the clamping strip 36 and the thickness of the filter cloth 7a are dimensioned such that the outside 38 of the filter cloth is in alignment with or does not appreciably project beyond the plane 15a spanned by the edge region 4a. The double ply 39, required for forming the hemstitch 37, of the filter cloth 7a is in this case arranged in the region of the groove 35. List of reference symbols 1 Membrane filter plate la Membrane filter plate 2 Intermediate plate 3 Baseplate 4 Edge region 4a Edge region 5 Boss 6 Membrane 7 Filter cloth 8 Groove 9 Annular bead 10 Fixing groove 11 Filter space 12 Groove wall 13 Portion 14 Fixing strip 15 Plane 15a Plane 16 Wall 17 Sealing lip IS Adhesive face 19 Top side 2 0 Edge space 22 Bore wZa r.-ore 23 Filtrate run-off bore 2 4 Connecting bore 25 Filtrate duct 2 6 Ar r ow 27 Pressure sp&ce 2 6 Baseplate region 29 Sealing groove 2 9a Sealing groove 3C Sealing projection 31 Supporting boss 32 Arrow 33 Groove 34 Sealing ring 35 Groove 36 Clamping strip 37 Hemstitch 38 Outside 39 Double ply Claims 1. A membrane filter press with at least one membrane filter plate (1) which comprises a baseplate (3) with a thickened edge region (4), a membrane (6) consisting of an elastically deformable material and a filter cloth (7), the membrane (6) having an edge-standing annular bead (9) seated in a complementarily configured groove (8) of the baseplate, characterized by a sealing groove (29) which is introduced in the baseplate (3) and which issues into the groove (8) at both ends in the manner of a bypass and in which a complementarily configured sealing projection (30) integrally formed onto the annular bead (9) is seated with a form fit. 2. The membrane filter press as claimed in claim 1, characterized in that, in the baseplate region bordered by the groove (8) and the sealing groove (29), there is at least or.e filtrate run-off bore (23) which is connected to a bore 22) passing through the membrane (6) . 3. The membrane filter press as claimed in claim 1 or 2, characterized in that the annular bead (9) and/or sealing groove (29) have an essentially dovetail-shaped cross se ction. 4. The membrane filter press as claimed in one of claims 1 to 3, characterized by a fixing groove (10) arrange: ir. the annular bead (9)■ and by a fixing strip (14) which is seated in said fixing groove and to which the filler cloth (7) is fastened indirectly or directly with its edge region. 5. The membrane filter press as claimed in claim 4, characterized in that the fixing strip (14) is seated in the fixing groove (1C) with a form fit effective transversely with respect to the plane of the baseplate (3) . 6. The membrane filter press as claimed in claim 4 or 5, characterized in that the fixing strip (14) is seated in the fixing groove (10) with a force fit. 7. The membrane filter press as claimed in one of claims 4 to 6, characterized in that the fixing strip (14) and the filter cloth (7) are arranged in the region of the annular bead (9) in such a way that they do not project beyond the plane (15) spanned by the edge region (4) of the baseplate (3). 8. The membrane filter press as claimed in claims 4 to 7, characterized in that the fixing strip (14) fills the fixing groove (10) essentially completely. 9. The membrane filter press as claimed in one of claims 4 to 8, characterized in that the annular bead (9) projects with a sealing lip (17) surrounding the fixing groove (10) beyond the plane (15) spanned by the baseplate edge region (4) . 10. The membrane filter press as claimed in one of claims 4 to 9, characterized in that the filter cloth (7) is clamped with its edge between the fixing strip (14) and the fixing groove (10). 11. The membrane filter press as- claimed in one of claims 4 to 10, characterized in that the fixing strip (14) is seated in the edge of the filter cloth (7a) , said edge being designed as a hemstitch (37). 12. The membrane filter press as claimed in one of claims 4 tc 11, characterized in that the filter cloth (7) is connected in a materially integral manner, in particular glued, with its edge to an- adhesive face (18) of the fixing strip (14). 13. The membrane filter press as claimed in claim 12 characterized in that the adhesive face (18) run parallel to the plane (15) and is in alignment wit that region of the membrane bead (9) which extend inward away from said plane.

Documents:

859-chenp-2005-abstract.pdf

859-chenp-2005-claims.pdf

859-chenp-2005-correspondnece-others.pdf

859-chenp-2005-correspondnece-po.pdf

859-chenp-2005-description(complete).pdf

859-chenp-2005-drawings.pdf

859-chenp-2005-form 1.pdf

859-chenp-2005-form 3.pdf

859-chenp-2005-form 5.pdf

859-chenp-2005-form18.pdf

859-chenp-2005-pct.pdf