Filter cloth panel for a disc filter and method of assembling the panel

Abstract

A filter cloth panel for use in a fabric or cloth-type disc filter is disclosed. The filter cloth panel includes a filter cloth, a filter cloth support, and a back panel. The filter cloth extends across the front or outer side of the filter cloth support and wraps back around an edge of the filter cloth support to where a portion of the filter cloth extends across the back side of the filter cloth support. The back frame is secured to the filter cloth support and in the process, the outer portion of the filter cloth is effectively secured to the filter cloth support about the back side thereof, and in the process of securing the frame to the filter cloth support, the filter cloth is appropriately tensioned across the front or outer side of the filter cloth support.

Description

[0001] C&B Ref. No.: 6114-082

[0002] FILTER CLOTH PANEL FOR A DISC FILTER AND METHOD OF ASSEMBLING THE PANEL

[0003] RELATED APPLICATIONS

[0004] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 683,291 filed on August 15, 2024, which is incorporated herein by reference in its entirety.

[0005] FIELD OF THE INVENTION

[0006] The present invention relates to a cloth or fabric disc filter, and more particularly to the design of a filter cloth panel employed in such disc filters.

[0007] BACKGROUND OF THE INVENTION

[0008] Cloth or fabric disc filters are used for water or wastewater filtration in industrial and municipal applications. They work by directing water containing suspended solids into and through an array of cloth covered discs. As the water passes through the cloth covered discs, suspended solids are captured or trapped on the surface of the cloth or within the cloth pores while the filtered water passes into the interior of the filter discs. The cleaned or filtered water is collected inside the filter discs and exits the filter disc through a drum on which the filter discs are mounted. From time-to-time, the filter cloth will accumulate suspended solids which need to be removed in order to maintain an acceptable level of filtration efficiency. Various means can be employed to clean and remove suspended solids from the filter cloth. For example, one approach is to periodically employ a backwashing cycle where clean water or air is forced backward through the filter cloth to dislodge and remove the trapped solids. In other cases, the suspended solids may be removed through a vacuum process.

[0009] One of the challenges in cloth disc filter design is that of designing a filter cloth panel that is robust and reliable and which is relatively easy to manufacture and assemble. Over a period of time, the cloth and its supporting frame structure is subjected not only to filtering large amounts of water directed under pressure through the filter cloth, but also the filter cloth is subjected to repeated backwashing or other forms of cleaning. These forces and stress on the filter cloth and its supporting frame structure over time can tear or wrinkle the filter cloth, and in some cases cause the filter cloth to detach from its supporting frame structure. This is why the manner of mounting the filter cloth to a panel and appropriately tensioning the filter cloth on the panel or other support structure is important. C&B Ref. No.: 6114-082

[0010] SUMMARY OF THE INVENTION

[0011] The present invention relates to a filter cloth panel that is used in cloth or fabric-type disc filters. The filter cloth panel includes a filter cloth support having first and second sides and a rim disposed on the second side. A filter cloth extends across the first side of the cloth support and then wraps around an edge of the cloth support where a portion of the filter cloth overlaps the rim. A back frame having a channel is seated over the rim and the portion of the filter cloth that laps over the rim such that the portion of the filter cloth that laps over the rim is held and sandwiched between the rim and the channel. This secures the filter cloth on the cloth support.

[0012] Furthermore, the present invention relates to assembling a filter cloth panel that is designed or configured to be employed in a fabric or cloth-type disc filter. This method entails placing a filter cloth across a first side of a cloth support and wrapping the filter cloth around an edge of the cloth support. The filter cloth is extended from the edge of the cloth support over a rim disposed on the second side of the cloth support. A back frame having a channel engages the filter cloth overlying the rim. The method further entails securing the cloth support and back frame together and, in the process, engaging the filter cloth overlying the rim with the channel of the back frame and seating the channel over the filter cloth and rim. This secures the filter cloth between the channel and the rim and further secures the filter cloth about the cloth support. In one particular embodiment, seating the channel over the filter cloth and rim acts to tension the filter cloth about the cloth support.

[0013] In another embodiment of the present invention, the filter cloth panel discussed above is incorporated into the fabric or cloth-type disc filter. In this case, the fabric or cloth-type disc filter includes a drum and one or more filter discs mounted on the drum. A drive is provided that rotates the drum and the filter discs during certain operations. Each filter disc includes a filter frame and a plurality of the filter cloth panels secured on opposite sides of the filter frame. The fabric or cloth-type disc filter is operative to direct wastewater into and through the filter cloth panels into an interior area of the filter discs. The filtered wastewater that ends up in the interior of the filter discs is then directed into the drum and thereafter discharged from the disc filter.

[0014] Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of the invention.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a high-level illustration of a cloth-type disc filter with a portion of its tank broken away to show an array of filter cloth panels mounted on a series of filter discs.

[0017] Figure 2 is an exploded perspective view showing the components of a filter cloth panel.

[0018] Figure 3 is a transverse cross-sectional view of a filter cloth panel along with an enlarged view of a portion of the panel. C&B Ref. No.: 6114-082

[0019] Figures 4A-4C are a sequence of views illustrating the assembly of the filter cloth panel with Figure 4A showing a filter cloth support and frame (inner or back frame) aligned before assembly.

[0020] Figure 4B illustrates the back frame being brought into contact with a portion of the filter cloth about the back side of the filter cloth support.

[0021] Figure 4C shows the back frame connected to the filter cloth support while Figures 4B and 4C illustrate how securing the back frame to the filter cloth support tensions the filter cloth.

[0022] DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0023] With further reference to the drawings, a cloth panel configured to be employed in a disc filter is shown therein and indicated generally by the numeral 10. Filter cloth panel 10 comprises a filter cloth 12, a filter cloth support 14, and a frame 16.

[0024] See Figure 2. Frame 16 may sometimes be referred to as an inner frame or a back frame since it assumes an inner position in a filter disc and forms the back of the filter cloth panel 10. As used herein, the terms “fabric” and “cloth” are used interchangeably. The structural makeup of the filter cloth 12 can vary. Essentially, the filter cloth 12 filters suspended solids from water or wastewater (the terms “water” and “wastewater” herein mean the same and the terms are used interchangeably). Generally, filter cloths of the type used in disc filters often employ textile cloth membranes of cellulose-based material, other natural fibers or synthetic fibers of a specific diameter, length or cross-sectional shape woven or napped into a tight, single layer or multiple layer fabric matting to obtain a desired thickness and porosity. These are some examples of the structural makeup of various types of filter cloth that can be used in a cloth-type disc filter.

[0025] As described in detail below, when the filter cloth panel 10 is assembled, the filter cloth 12 extends across the outer side (sometimes referred to as the first side) of the cloth support 14. Outer portions 12A of the filter cloth 12 are wrapped around the outer edge 14A of the cloth support 14. An outer edge 12B of the filter cloth 12 terminates about the back (sometimes referred to the second side) of the filter cloth support 14. See Figure 3. Filter cloth support 14 can assume various designs. In the exemplary design shown in the drawings and discussed herein, the filter cloth support 14 assumes an open grid structure. As described more fully below, the back frame 16 is secured to the filter cloth support 14 in such a way that outer portions 12A of the filter cloth 12 are securely held between the cloth support 14 and the back frame 16.

[0026] Formed on the back side of the filter cloth support 14 is a rim 18. Rim 18 is spaced slightly inward of the outer edge 14A of the cloth support 14. See Figure 3. Additionally, rim 18 projects from the back side of the filter cloth support 14 and extends around the back side of the cloth support continuously or substantially continuously. Rim 18 can assume various shapes but in the exemplary embodiment shown in the drawings, the rim assumes a U-shape. C&B Ref. No.: 6114-082

[0027] Turning to the back frame 16, formed on the front side thereof is an open-sided channel 20. As viewed in Figure 4A, the channel 20 includes two walls or legs 20A and 20B. Note that wall 20A is slightly longer than wall 20B. Like rim 18, channel 20 is spaced slightly inwardly from the outer edge 16A of the frame 16. Channel 20 extends around the periphery of the back frame 16. Furthermore, rim 18 and channel 20 are dimensioned and arranged on the filter cloth support 14 and frame 16, respectively, so as to mate or overlie when the frame is secured to the filter cloth support.

[0028] Rim 18 and channel 20 perform two basic functions in a preferred embodiment. First, they cooperate to engage outer portions 12A of the filter cloth 12 and firmly secure the filter cloth about the filter cloth support 14. Secondly, in the course of assembling the filter cloth panel 10, the rim 18 and channel 20 cooperate to engage outer portions 12A of the filter cloth 12 and to tension the filter cloth across the outer side of the filter cloth support 14.

[0029] Figures 4A-4C illustrate a method of assembling the filter cloth panel 10. Filter cloth 12 is dimensioned such that it covers the outer side of the filter cloth support 14 and include sufficient additional surface area that allows the outer portions 12A to be lapped around the edge 14A of the filter cloth support 14 and extend at least slightly over the rim 18. See Figure 4A. Note that the outer portions 12A of the filter cloth 12 extends from edge 14A over the rim 18. As viewed in Figure 4A, note that a segment of the outer portions of the filter cloth extends in a general straight line from the edge 14A of the filter cloth support 14 to the rim 18. That, as discussed below, will facilitate the tensioning of the filter cloth 12 during the assembly of the filter cloth panel 10. Rim 18 and channel 20 arrangement, as partially shown in Figures 4A-4C, extends completely around the filter cloth support 14 and the back frame 16.

[0030] Once the filter cloth 12 is laid out and assumes the position shown in Figure 4A, the back panel 16 is positioned over or adjacent the filter cloth support 14. In this position, channel 20 aligns with the rim 18 and this alignment occurs around the filter cloth support 14 and back panel 16.

[0031] Figure 4B illustrates the back frame 16 being brought into contact with the filter cloth 12 overlying the rim 18. Note again that the channel 20 includes two walls or legs 20A and 20B. The innermost wall or leg 20A is slightly longer than the outer wall or leg 20B. As the back frame 16 is brought into contact with the filter cloth 12 overlying the rim 18, it is seen that the inner wall 20A first engages the filter cloth overlying the rim 18. Channel 20 is particularly configured such that the inner wall 20A tends to hold and secure the filter cloth tightly against the rim 18 such that it resists being pulled from right to left in Figure 4B. As the back frame 16 is continued to be moved towards the filter cloth support 14, the outer wall 20B engages the filter cloth 12 disposed on the outboard side of the rim 18, and as the frame 16 is moved to the position shown in Figure 4C the outer wall will effectively stretch and tension the filter cloth across the filter cloth support 14. C&B Ref. No.: 6114-082

[0032] There is provided a series of fasteners 22 that are utilized to fasten the back frame 16 to the filter cloth support 14. Fasteners 22 are spaced apart and extend through the web 20C of the channel 20 and between legs 20A and 20B. Fasteners 22 extend through the filter cloth 12 overlying the rim 18. From the filter cloth 12, the fasteners 22 extend through the rim 18 and in the process secure the back frame 16 to the filter cloth support 14. This causes the outer leg 20B to exert a tensioning force on the filter cloth 12 extending across the front side of the filter cloth support 14.

[0033] In order to properly tension the filter cloth 12 across the outer side of the filter cloth support 14, the fasteners 22 can be uniformly screwed down into the rim 18 such that the filter cloth is uniformly tensioned around the filter cloth support 14. This can be achieved by simultaneously screwing down all of the fasteners 22 of the filter cloth panel 10. If not, the fasteners one-by-one can be turned down in small increments until the channel 20 seats completely over the filter cloth and the rim 18.

[0034] The filter cloth panel 10 discussed above and shown in the drawings is suitable for use in what is generally referred to as a fabric or cloth disc filter. See Figure 1 . Details of a fabric or cloth disc filter are not dealt with herein because generally these disc filters are well known and appreciated by those skilled in the art, and details of which are not per se material to the present invention. However, see U.S. Patents 6,294,098; 4,090,965; and 4,639,315, the disclosures of which are expressly incorporated herein by reference. Suffice it to say that generally speaking, cloth disc filters include a drum 24 having a series of spaced apart filter discs 28 mounted thereon. See Figure 1 . Each filter disc 28 includes a frame structure 26. Frame structure 26 is particularly designed and configured to accept and support a series filter cloth panels 10. In the exemplary embodiment shown, the filter disc frame 26 includes 12 compartments. Each compartment is formed by a pair of filter cloth panels 10 disposed and supported on opposite sides of the filter disc 28. Each set of filter cloth panels 10 defines an internal chamber or area within the filter disc 28 for receiving filtered water or wastewater that passes through the filter cloth 12 that forms a part of the filter cloth panels 10. There are various ways that individual filter cloth panels 10 can be secured to the filter frame 26. In one example, the filter frame 26 can include slots or grooves that allow individual filter cloth panels 10 to be inserted into the filter frame 26 from the outer periphery of the filter frame, after which the filter cloth panels are pushed inward to a set position and secured by an outer periphery rim that extends around the filter disc 28.

[0035] As noted above, between each set of filter cloth panels 10 there is defined a chamber or open space for receiving filtered wastewater. The wastewater being treated, as noted above, typically contains suspended solids and is directed into a tank, such as that shown in Figure 1 , that contains the drum 24 and filter discs 28. Once in the tank, due to a pressure differential or vacuum, for example, the wastewater containing the suspended solids is directed or forced C&B Ref. No.: 6114-082 through the filter cloth 12 disposed about opposite sides of the filter discs 28 into the open chamber within the filter discs. As the influent wastewater passes through the filter cloth 12, suspended solids and other particulate matter therein are captured by the filter cloth. The filtered water inside the filter discs 28 can then move into the drum 24 and then out of the tank.

[0036] Various types of systems can be employed from time-to-time to remove suspended solids and particulate matter captured on or in the filter cloth 12. In some cases, these systems for removing suspended solids may entail backwashing, and in other cases vacuum systems can be employed to sweep the collected suspended solids from the filter cloth 12. In any event, such systems and processes for removing suspended solids and particulate matter from the filter cloth 12 are well known and appreciated by those skilled in the art.

[0037] There are many advantages to the filter cloth panel 10 of the present invention. First, the filter cloth panel 10 is strong and robust and will reliably and efficiently filter water or wastewater without easily being subjected to damage. Further, the assembly process effectively tensions the filter cloth 12 about the filter cloth support 14. That is, as described above, in assembling the filter cloth panel 10 and particularly securing the inner or back frame 16 to the filter cloth support 14, the process entails the filter cloth 12 being engaged by both the filter cloth support 14 and back panel 16 such that as the panel is secured to the filter cloth support, the filter cloth 12 is effectively tensioned about the filter cloth support 14.

[0038] The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments disclosed herein are therefore to be construed in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

C&B Ref. No.: 6114-082CLAIMSWhat is claimed is:1 . A cloth disc filter for filtering wastewater, comprising: a drum; one or more filter discs mounted on the drum; a drive operatively connected to the drum for rotating the drum and the one or more filter discs mounted on the drum; each filter disc including a filter frame and a plurality of filter cloth panels secured on each side of the filter frame; each filter cloth panel including: i. a cloth support having first and second sides and a rim disposed on the second side; ii. a filter cloth extending across the first side of the cloth support and which wraps around an edge of the cloth supports where a portion of the filter cloth laps over the rum; andHi. a frame having a channel seated over the rim and the portion of the filter cloth that laps over the rim such that the portion of the filter cloth that laps over the rim is held and sandwiched between the rim and the channel; and wherein the cloth disc filter is configured to filter the wastewater by directing the wastewater through the filter cloth panels into an interior area of the filter disc to yield filtered wastewater, after which the filtered wastewater passes into the drum.

2. The cloth disc filter of claim 1 wherein each filter cloth panel includes a series of fasteners that extend through the channel, through the portion of the filter cloth that laps over the rim and into the rim, thereby securing the frame to the cloth support.

3. The cloth disc filter of claim 2 wherein the filter cloth extending across the first side of the cloth support is maintained and tensioned by the channel seated over the rim with a portion of the filter cloth lying therebetween.

4. The cloth disc filter of claim 1 wherein the rim of the cloth support assumes a generally U-shape and wherein the channel is configured to tightly seat over the rim and the intervening filter cloth.

5. The cloth disc filter of claim 1 wherein the rim of the cloth support extends substantially continuously around a portion of the perimeter of the cloth support, wherein the channel extends substantially continuously around a portion of the frame.C&B Ref. No.: 6114-0826. A method of assembling a filter cloth panel configured to be employed in a disc filter comprising: placing a filter cloth across a first side of a cloth support; wrapping the filter cloth around an edge of the cloth support; extending the filter cloth from the edge of the cloth support over a rim disposed on the second side of the cloth support; placing a frame adjacent the second side of the cloth support; engaging the filter cloth overlying the rim with a channel on the frame; and securing the cloth support and frame together and engaging the filter cloth overlying the rim with the channel and seating the channel over the filter cloth and rim, thereby securing the filter cloth between the channel and the rim which secures the filter cloth about the cloth support.

7. The method of claim 6 wherein seating the channel over the filter cloth and rim tensions the filter cloth about the cloth support.

8. The method of claim 6 wherein during the course of seating the channel over the filter cloth and rim, one portion of the channel engages and holds the filter cloth, while another portion of the channel engages and stretches the filter cloth.

9. The method of claim 6 wherein the rim of the cloth support is spaced inwardly from an edge of the cloth support and extends completely or substantially completely around an outer portion of the cloth support10. The method of claim 6 wherein the channel of the frame and the rim of the cloth support are congruent.11 . The method of claim 6 further including mounting the filter cloth panel in a section of a disc-shaped frame that forms a part of the disc filter.

12. A filter cloth panel for a disc filter comprising: a cloth support having first and second sides and a rim disposed on the second side; a filter cloth extending across the first side of the cloth support and which wraps around an edge of the cloth support where a portion of the filter cloth laps over the rim; andC&B Ref. No.: 6114-082 a frame having a channel seated over the rim and the portion of the filter cloth that laps over the rim such that the portion of the filter cloth that laps over the rim is held and sandwiched between the rim and the channel.

13. The filter cloth panel of claim 12 including a series of fasteners that extend through the channel, through the portion of the filter cloth that laps over the rim, and into the rim, thereby securing the frame to the cloth support.

14. The filter cloth panel of claim 13 wherein the filter cloth extending across the first side of the cloth support is maintained and tensioned by the channel seated over the rim with a portion of the filter cloth lying therebetween.

15. The filter cloth panel of claim 12 wherein the rim assumes a generally U-shape and wherein the channel is configured to tightly seat over the rim and the intervening filter cloth.

16. The filter cloth panel of claim 12 wherein the rim extends substantially continuously around a portion of the perimeter of the cloth support; and wherein the channel extends substantially continuously around a portion of the frame.

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