Membrane module manifold with integral end caps

Abstract

To provide a membrane filter system.SOLUTION: Silicon carbide flat sheet filtration membranes are supported on one piece manifold / end cap structures. Ends of a large number of parallel flat plate membranes are fitted into elongated end cap slots that are part of a single molded manifold / end cap structure, such a structure being at each end of a series of membranes. In addition, one piece external frame module can be provided to receive the bundle of flat plate membranes with attached manifold / end caps. When damaged, the plate can be removed and replaced along with a special end cap repair section. This provides advantages over prior arrangements with individual end caps for each module or potting of the flat plates into a box or chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to membrane filtration, and more particularly to an apparatus for directing filtered permeate from a flat-plate ceramic membrane. [Background technology]

[0002] The majority of silicon carbide (SiC) flat sheet suppliers use flat sheet filters with end caps. These end caps (referred to herein as end cap type) have O-rings and are inserted into a single permeate header. Filtered water travels from the exterior of the SiC filter plates through channels inside the plates, into the end caps, and from there into the permeate header. One or two suppliers "pot" the flat plates into a box or chamber on the ends (referred to herein as potted type), so that water travels directly into the voids at the ends.

[0003] The main problem with the end cap type is that it requires numerous O-rings, which are expensive to manufacture and install and subject to failure. The main advantage is that the individual flat-sheet membranes can be individually replaced if damaged. The main problem with the snap-in type is that the polyurethane used to "snap" the flat-sheet membranes can expand and contract significantly with temperature changes in submerged applications. This expansion and contraction can crack the brittle membrane flat sheets. Additionally, snap-in plates prevent individual sheets from being replaced.

[0004] The same type of sealant (polyurethane) is typically used in both applications, which does not present end cap type problems because the amount of sealant is very small and the impact is very minimal. In addition, there is only a small gap between the plates. Summary of the Invention [Means for solving the problem]

[0005] The present invention solves the above problems with a single-piece, and preferably integrally molded, manifold and end cap set. Using the manifold / end cap structure of the present invention, the amount of sealant required is significantly reduced and, importantly, O-rings are eliminated. In a primary embodiment of the present invention, a damaged membrane plate may be replaced, which involves engaging a patch of some kind with the manifold. While a single-piece, integral design is preferred, the manifold / end cap structure may also be formed of multiple pieces assembled together in a sealing relationship.

[0006] Additionally, the present invention, in one embodiment, can have a single-piece external frame module that receives all of the membranes in an assembly that is held by manifold / end cap structural units at each end. The assembly, which may have, for example, 20 or 25 membranes, is lowered into a position where the modular frame engages the end cap / manifold units, thereby helping to provide rigid structural support for the membrane plates in use.

[0007] A key objective of this invention is to eliminate O-rings in flat-plate ceramic membrane assemblies while providing a one-piece end cap / manifold structure that efficiently attaches to a series of membrane plates, allows for individual membrane replacement, and is structurally reliable and robust. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a perspective view showing an assembly or cassette of a series of ceramic flat plate membranes held at both ends by a manifold / end cap unit of the present invention. [Figure 2] FIG. 1 is a top view of the manifold / end cap unit of the present invention. [Figure 3] FIG. 1 is a perspective view showing the present invention in more detail. [Figure 4] FIG. 2 is a top view of the assembly of FIG. 1 showing a damaged plate in the ceramic membrane plate. [Figure 5] FIG. 5 is a similar view to FIG. 4 showing the damaged plate being removed. [Figure 6] 1 is a cross-sectional elevation view showing the removal of a broken membrane plate with the aid of a cutting jig in accordance with the present invention. FIG. [Figure 7] Detailed enlarged top view showing the cutting jig engaged on the end cap / manifold. [Figure 8] This is a perspective view showing the cutting jig. [Figure 9] FIG. 1 is a perspective view of a replacement plate end cap of the present invention. [Figure 9A] FIG. 10 is a perspective view of an alternative repair coupling for the device shown in FIG. 9. [Figure 10] FIG. 11 is a perspective view of an assembly or cassette of plates held by an end cap / manifold showing the removal and replacement of a damaged plate in three stages. [Figure 11] FIG. 2 is a perspective view showing an outer frame module for receiving the assembly plate of FIG. 1. [Figure 12] FIG. 1 is a perspective view showing the stacking and organization of plate assemblies held within the outer frame module. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the drawings, Figure 1 shows an assembly or cassette 10 of multiple flat-plate ceramic filtration membranes 12 (e.g., about 20 or 25 plates) held together as a unit by end caps / manifolds 14, one at each end of the plate assembly. In some cases, one end of the plates may be uncapped so that an end cap / manifold structure is connected to receive permeate from the plates at only one end of the plates, while the other end is supported or held in a suitable manner. Each plate has an end that is received in a slot in the manifold / end cap structure at each end.

[0010] Figure 2 shows a top view of the end caps / manifolds 14, and Figure 3 also shows these end caps / manifolds 14 in more detail, engaged with a membrane. Each manifold / end cap structure 14 has a header 16 (sometimes called a header pipe), which is a permeate collection pipe, and a series of end caps 18 connected to and in fluid communication with the interior of the header 16. Each end cap is elongated, extends the full height of the membrane, and defines a slot 20 sized to fit closely over and receive the end of a membrane plate. The ends of the membrane plates 12 are open, feeding permeate into the end caps, which are firmly bonded to the membrane plates using cement typically applied to connect prior art end caps to ducts or pipes. As can be seen in the drawing, the downstream structure of the end caps 18 narrows toward a neck 22, which extends the full height of the membrane plate and end caps and is connected at the top to the header pipe 16, thereby feeding liquid into the header. Preferably, the entire end cap / manifold unit 14 structure is integrally molded as a single piece of a suitable plastic material such as Noryl, or a Nylon-ABS blend, or other durable plastic that is safe for potential sewerage applications.

[0011] The narrow necks 22 on the end caps provide flexibility. The necks 22 secure the membrane plates to the end caps 18 away from the header pipes 16, allowing the plates to bend or flex in a limited manner; the end caps are connected in fluid communication at their tops to the header pipes 16, holding the plates rigid but allowing some flexing, thereby preventing breakage. Additionally, the end caps 18 may be connected together at the bottom or elsewhere, thereby improving rigidity. By way of example, if the manifold / end cap structure is dimensioned as shown in FIG. 7, the neck may have a width of approximately 7 mm and protrude approximately 4-5 mm from the vertical tangent of the header pipe.

[0012] The drawings, including Figures 1, 2, and 3, show outlet ducts 24 on each end cap / manifold 14. These outlet ducts 24 are intended to be connected to conduits or pipes for removing permeate, typically from a series assembly. As shown, these outlet ducts are equipped with several large O-rings (not shown) for a fluid-tight connection. However, end caps 18 do not require O-rings. In the prior art, end caps were provided with numerous small O-rings that secured the end cap to the pipe or permeate header, and therefore some of the O-rings often failed.

[0013] Figure 4 shows the assembly 10 in plan view, while Figure 5 shows the same assembly, but with the damaged membrane plate 26 removed. Figures 5 through 10 illustrate the procedure for removing and replacing a damaged ceramic plate. In Figure 6, an elevational cross-section of one of the flat-plate membranes 12, a jig 28 is shown engaged on the manifold / end cap header 16. The jig 28 is also shown in Figures 7, 8, and 10. Note that the view of the jig 28 in Figure 6 is also in cross section. Figure 7 further illustrates the use of the jig, while Figure 8 shows the jig itself. Figure 6 also shows the hacksaw blade cut line 30, where the jig provides a guide for the cut through the header 16 to receive one section of the header. Two parallel cuts are made, as shown in Figure 10, resulting in a gap being cut out of the header. This gap is wide enough to encompass the header on either side of the end cap's narrow neck 22, which in one example is approximately 7 mm wide. Both headers 16 are cut as shown in Figure 10, separating each header into two pieces, each piece holding the remaining membrane plate 12. The damaged plate 26 has been removed in Figure 10 by simply lifting it up with its end caps attached and with the short sections of headers, one on each end.

[0014] If desired, the cut through the header pipe may be made without a jig and therefore a grinder rather than a blade may be used.

[0015] Figure 7 shows the end cap / manifold 14 in more detail with the cutting jig 28 engaged. In this view, the cut has been made and a section of the header / end cap removed. This drawing shows that the unitary end caps of the end cap / manifold structure 14 are as close together as molding will allow, separated by a space of less than about 1 mm. They may be joined during molding, but are preferably separated or only minimally connected as noted above to better facilitate removal and replacement of the plates.

[0016] Figure 10 shows a replacement plate 31 with special end cap replacement sections 32 at each end. The end caps or end cap replacement sections 32 are also shown in Figure 9 before being attached to the ceramic plate.

[0017] 10 shows a replacement plate 31 with a special end cap 32 being moved into place after a damaged or defective plate 26 has been removed from the plate assembly, leaving a gap. The manifold 16 may be spaced apart to accommodate the annular collar 34 of the end cap 32, which has a width greater than the gap and, therefore, greater than the section of manifold that was removed. This section of manifold is then replaced in place over the collar, and an adhesive sealant is applied to permanently attach the collar to the manifold. For the end cap / manifold construction described above with a neck having a width of approximately 7 mm, the collar 34 may have a width of approximately 19 mm.

[0018] Furthermore, after removing the membrane plate, it is possible to simply repair damage in the header 16 without replacing the defective membrane plate. A coupling sleeve, as shown in Figure 9A, rejoins the separated sections of the header.

[0019] 7 shows the end caps 18 spaced only slightly apart, preferably as closely as possible to form the structure by injection molding. As mentioned above, the end caps 18 may actually be connected with no gap between them, and a saw blade may be used to cut between the end caps to extract this section of the header pipe 14.

[0020] Figures 11 and 12 show a single-piece external frame module 38, preferably a single piece of plastic molding, configured to receive an assembly or cassette of plates 12 with end caps / headers 14 as shown in Figure 1. As the figures reveal, the interior end wall 40 of the module 38 preferably has a series of vertically extending parallel grooves 42 into which the outer ends 44 of the end caps 14 can slide, thereby providing a firm and complementary fit to the module if additional structure is required for this purpose. Figure 12 shows an assembly of plates housed within a module, with four plate-receiving modules 38 arranged in a side-by-side stacked configuration. Permeate from all of these plate sets can be conveyed out in a pipe connected to the outlet duct 24. Suction is applied to the membranes via the outlet duct 24.

[0021] The above-described preferred embodiments are intended to illustrate the principles of the present invention and are not intended to limit the scope of the invention. Other embodiments and variations on these preferred embodiments will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the invention as defined in the following claims.

Claims

1. 1. A membrane filtration system comprising a series of microfiltration membranes receiving a liquid at an outer surface for the purpose of removing contaminants and adding a permeate to the interior of the membranes, the permeate being directed out through a pipe, the system comprising: a membrane that is a ceramic flat plate membrane arranged in an adjacent parallel planar configuration; a series of membrane plates in a plate assembly having an end cap / manifold structure of molded plastic material at at least one end of the plates, the end cap / manifold structure having an overlying generally horizontal header and a series of vertically oriented end caps, each of the end caps having a slot that fits closely over and is adhered to an end of the plate, the end caps being in fluid communication with the header such that the end caps receive permeate from the membranes, thereby fluidly connecting the permeate from the plates into the header; said plate assembly having no O-rings at the end caps; Equipped with a membrane filtration system wherein the membrane plates are maintained within the assembly by the end cap / manifold structure and are rigidly connected to the end cap / manifold structure without the use of O-rings to form a fluid-tight relationship with the end cap / manifold structure.

2. The membrane filtration system of claim 1 , wherein the end cap / manifold structure is integrally molded as a single piece.

3. 2. The membrane filtration system of claim 1, further comprising replacement end cap sections for replacing damaged membrane plates, each of the replacement end cap sections having an annular collar for fitting closely onto the header pipe, and a replacement end cap integral with and extending downward from the annular collar, the replacement end cap having a slot for fitting closely onto the end of the replacement membrane plate, whereby the header pipe in a plate assembly having a damaged membrane plate can be ground or cut in two locations on either side of the integral end cap of the assembly to remove the damaged membrane plate and a short section of header, and then a replacement plate having replacement end cap sections at one or both ends can be placed in place, where the annular collar of the replacement end cap section is slid through the header pipe and secured to the header pipe with an adhesive.

4. 2. The membrane filtration system of claim 1, further comprising a repair coupling for the header to fit tightly through the header, wherein the header pipe in a plate assembly having a broken membrane plate can be ground or cut in two locations on either side of an integral end cap of the assembly to remove the broken membrane plate and a short section of the header, and then a repair coupling can be placed in place where the repair coupling is slid through the header, thereby joining the separated sections of the header together and securing them with an adhesive.

5. The membrane filtration system of claim 1 , wherein the membrane filtration system receives treated wastewater in a wastewater treatment plant.

6. 1. A method for replacing an individual damaged membrane plate while maintaining the remaining membrane plates in an assembly in a wastewater treatment system having multiple flat plate membranes connected to a manifold, comprising: providing an end cap / manifold structure integrally molded as a single piece with header pipes, wherein a series of vertically oriented end caps are connected to the header pipes, each end cap having a slot configured to fit closely over an end of a membrane plate, the end caps and the header pipes being fluidly connected such that the end caps can receive permeate from the membranes and thereby direct the permeate into the headers; assembling a series of flat plate membranes in spaced parallel relationship to at least one end cap / manifold structure, the membrane plate ends being inserted into the end cap slots at one end of the membrane plates, and applying a sealing adhesive to secure the membrane plate ends in the slots to form a plate assembly; operating the plate assembly in a bath of liquid to be filtered, such that the liquid is drawn into the pores of the membrane plates, through the membrane plates, into the end caps, and finally into the header pipes, and a pipe connected to the header pipes is used to carry the permeate of the liquid out; Upon breakage, damage, or failure of one of the membrane plates, removing a short section of the header pipe, thereby having the end cap secured to the broken membrane plate, and removing the broken membrane plate and a section of header pipe between two separate sections of header pipe, thereby leaving a gap in the header pipe where the broken membrane plate was located; (a) providing replacement end cap sections to replace the damaged membrane plate and header pipe of the removed section, each of the replacement end cap sections having an annular collar for fitting closely over the header pipe and an end cap integral with and extending downwardly from the annular collar, the end cap having a slot for fitting closely over an end of a replacement membrane plate, attaching and adhering a replacement membrane plate to the replacement end cap section of the replacement membrane plate, and positioning the annular collar of the replacement section of the end cap into the gap of the header pipe and sliding the header pipe into the annular collar on either side of the annular collar with an applied adhesive, thereby splicing the header pipe and attaching the replacement membrane plate; or (b) providing a repair coupling that fits tightly onto the header pipe, and further rejoining the separated sections of the header by sliding the repair coupling over both of the separated sections of the header using adhesive to seal the repair coupling to the header pipe, without placing a new membrane in place of the damaged membrane plate. replacing the damaged membrane plate by either A method comprising:

7. 7. The method of claim 6, wherein removing a section of a header pipe includes using a jig and cutting out a section of the header pipe with an integral end cap carrying the broken membrane plate.

8. 7. The method of claim 6, wherein removing a section of a header pipe comprises grinding or cutting the section from the remainder of the header pipe.

9. 1. A set of components for a membrane filtration system comprising a series of microfiltration membranes that receive liquid at their outer surfaces for the purpose of removing contaminants and adding permeate to the interior of the membranes, the permeate being directed outward through a pipe, the set of components comprising: a membrane that is a ceramic flat plate membrane arranged in an adjacent parallel planar configuration; a series of membrane plates in a plate assembly having an integral end cap / manifold structure of molded plastic material at at least one end of the plates, the end cap / manifold structure having an overlying generally horizontal header and a series of vertically oriented end caps, each of the end caps having a slot that fits closely over and is adhered to an end of the plate, the end caps being in fluid communication with the header such that the end caps receive permeate from the membranes and deliver the permeate into the header; a plurality of end cap replacement sections for replacing damaged membrane plates, each end cap replacement section having a collar for closely fitting onto the header pipe, and a replacement end cap integral with and extending downwardly from the collar, the replacement end cap having a slot for closely fitting onto an end of the replacement membrane plate; Equipped with The header pipe in the plate assembly having the broken membrane plate may be ground or cut in two locations on either side of the integral end cap of the end cap / manifold structure to remove the broken membrane plate and a short section of header pipe at the end of the broken membrane plate, and then a replacement plate having a replacement end cap section may be placed in place, where the collar of the replacement end cap section is slid over the header pipe and secured to the header pipe with an adhesive. A set of parts.

10. 10. The set of parts of claim 9, wherein said end cap / manifold structure is a unitary, integral, single piece molding.

11. 10. The set of parts of claim 9, wherein said plate assembly has two of said end cap / manifold structures, one at each end of each of said series of plates.

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