Patent Publication Number: US-2022233978-A1

Title: Self-cleaning filter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to as a continuation-in-part and as the international application of U.S. patent application Ser. No. 16/432,706 filed on Jun. 5, 2019 and entitled “Self-Cleaning Filter,” which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not applicable. 
     BACKGROUND 
     Industrial fluid filters may be utilized across various industries such as oil and gas, power generation, water and waste water, battery production, food processing, metals plating and galvanizing, and chemical processing. For instance, one type of fluid filter includes a vessel with an inlet for receiving a fluid to be filtered and an outlet for discharging a filtered fluid from the vessel. 
     SUMMARY 
     In an embodiment, a filter may include: a tube comprising perforations, the tube configured to receive a flow of a gas from a first direction or a flow of a liquid from a second direction opposite to the first direction; a filter media positioned concentrically around the tube; and spacers positioned between the tube and the filter media to create a space between the tube and the filter media; wherein a portion of the filter media is configured to flex inward into the space during the flow of liquid into the filter, and flex outward from the space during the flow of gas exiting the filter. 
     In an embodiment, a filter may include: a plurality of tubes, each tube comprising perforations and each tube configured to receive a flow of a gas from a first direction or a flow of a liquid from a second direction opposite to the first direction; and a filter media positioned concentrically around the tubes to form a space between two tubes and a portion of the filter media; wherein the portion of the filter media is configured to flex inward into the space during the flow of liquid into the filter, and flex outward from the space during the flow of gas exiting the filter. 
     In an embodiment, a method may include: receiving liquid in a vessel including a filter; receiving the liquid in the filter from a first direction, wherein the filter comprises: a tube including perforations; a filter media positioned concentrically around the tube; and spacers positioned between the tube and the filter media to create a space between the tube and the filter media. The method may further include: flexing a portion of the filter media inward into the space upon receipt of the liquid; accumulating filter cake with the filter media; receiving gas into the filter from a second direction opposite to the first direction; and flexing the portion of the filter media outward from the space upon receipt of the gas, to remove the filter cake from the filter media. 
     In an embodiment, a method may include receiving liquid in a vessel including a filter; receiving the liquid in the filter from a first direction, wherein the filter comprises: a plurality of tubes, each tube comprising perforations; and a filter media positioned concentrically around the tubes to form a space between two tubes and a portion of the filter media. The method may further include flexing the portion of the filter media inward into the space upon receipt of the liquid; accumulating filter cake with the filter media; receiving gas in the filter from a second direction opposite to the first direction; and flexing the portion of the filter media outward from the space upon receipt of the gas, to remove the filter cake from the filter media. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG. 1A  illustrates a self-cleaning filter, in accordance with an embodiment of the disclosure. 
         FIG. 1B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 1A , in accordance with an embodiment of the disclosure. 
         FIG. 2A  illustrates a self-cleaning filter with a reinforcement core, in accordance with an embodiment of the disclosure. 
         FIG. 2B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 2A , in accordance with an embodiment of the disclosure. 
         FIG. 2C  is another view of the self-cleaning filter shown on  FIG. 2A , in accordance with an embodiment of the disclosure. 
         FIG. 2D  is a bottom view of the self-cleaning filter shown on  FIG. 2A , in accordance with an embodiment of the disclosure. 
         FIGS. 3A and 3B  illustrate flexing of a filter media, in accordance with an embodiment of the disclosure. 
         FIG. 4A  illustrates a self-cleaning filter, in accordance with an embodiment of the disclosure. 
         FIG. 4B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 4A , in accordance with an embodiment of the disclosure. 
         FIG. 4C  is another view of the self-cleaning filter shown on  FIG. 4A , in accordance with an embodiment of the disclosure. 
         FIG. 5A  illustrates a self-cleaning filter, in accordance with an embodiment of the disclosure. 
         FIG. 5B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 5A , in accordance with an embodiment of the disclosure. 
         FIG. 5C  is another view of the self-cleaning filter shown on  FIG. 5A , in accordance with an embodiment of the disclosure. 
         FIG. 6A  illustrates a self-cleaning filter with a reinforcement core, in accordance with an embodiment of the disclosure. 
         FIG. 6B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 6A , in accordance with an embodiment of the disclosure. 
         FIGS. 7A and 7B  illustrate flexing of a filter media, in accordance with an embodiment of the disclosure. 
         FIG. 8A  illustrates a self-cleaning filter, in accordance with an embodiment of the disclosure. 
         FIG. 8B  is a top view/bottom view of the self-cleaning filter shown on  FIG. 8A , in accordance with an embodiment of the disclosure. 
         FIGS. 8C and 8D  illustrate flexing of a filter media, in accordance with an embodiment of the disclosure. 
         FIG. 9  is a schematic illustration of a filtering system according to an embodiment. 
         FIGS. 10A-10F  illustrate an operation of a self-cleaning filter with a filtrate tube, in accordance with an embodiment of the disclosure. 
         FIGS. 11A-11F  illustrate an operation of a self-cleaning filter without a filtrate tube, in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates generally to a self-cleaning filter. A variety of filtration media can be used to filter fluids in various industries that rely on filters to clean fluids. In some industries, filtration assemblies can use discs of filtration media retained by filter plates. The fluid that is being filtered can enter into a central space and flow outwards through the stacked discs of filtration media and filter plates that retain the filtration media in position. When the filtration media is saturated with the components being filtered, the entire filter assembly is removed to allow the filtration media to be replaced. This can entail removing the entire stack of filtration media discs and the filtration plates while the filtration media is saturated with the liquid. This process is time consuming and can expose workers to harmful chemicals. Once the filtration media discs are replaced, the entire assembly can then be replaced for further filtration. The use of filtration media discs results in a large amount of waste. In addition to the components that are filtered from the fluid, the filtration media in the discs is generally discarded as well. When the liquid being filtered is still present in the filtration media discs, there is a loss of potentially valuable liquid as well. 
     Other filter structures can include filter cartridges in which filtration media is maintained. The media being filtered can be passed through the filtration cartridges, and once saturated, the entire filter cartridges can be removed and discarded. This can generate large amounts of waste that can include the filter cartridge, the component being filtered, and additional fluids retained within the filtration media. 
     Disclosed herein is a self-cleaning filter assembly that reduces the amount of waste produced by the filter assembly while also reducing the exposure of the workers to the liquid being filtered. The self-cleaning filter may include a filter tube having a filtration media disposed around the filter tube. In some embodiments, a reinforcement core and/or a volume reducer can be disposed within the filter tube to aid in self-cleaning by reducing a volume of a chamber to receive air or another gas to allow for cleaning of the filter media. Due to its configuration, the self-cleaning filter can have a surface area selected to allow a large flow of fluid to enter the self-cleaning filter, where the surface area can be as large as needed for the specific filter design. As the self-cleaning filter assembly is used, the components to be removed from a liquid can form a filter cake on the exterior of the filtration media. 
     Once the filter cake is to be removed, the filter assembly can be drained of the liquid being filtered. The filter cake can then be dried in place, thereby further removing the liquid being filtered and reducing the amount of material that is disposed of from the filter. The filter assembly can then be back-pulsed with gas to remove the filter cake. As described in more detail below, the shape of the filter tube can be selected through various designs to have a non-smooth surface. The filtration of the fluid and formation of the filter cake can then result in a non-round shape that can be expanded by the back-pulsing of gas. The expansion can result in the dried filter cake dislodging from the filtration media breaking off of and fall from the filtration media, thereby cleaning the filtration media. The dried filter cake can then be collected and disposed of separately from the filtration media, which can be reused. This system reduces the total volume of waste, while also allowing for the removal of the components removed from the fluid without the need for workers to handle the removed components directly. 
       FIGS. 1A and 1B  illustrate a self-cleaning filter  100  with a single tube  102  (“tube  102 ”). The tube  102  serves as a structural support for the filter media  108 . For example, when fluid flows from outside of the filter media  108  into the center of the tube  102 , the tube  102  holds the flexible filter media  108  and retains the filter media  108  in position while the fluid is filtered. The tube can have a plurality of openings or perforation  104  to allow fluid to flow into the center of the tube  102 . The perforations  104  are flow passages that may be arranged in columns and rows. While shown as a tube  102  having a round cross section, the tube can have other cross-sectional shapes depending on the use of the filter and the filtering conditions. 
     The tube  102  can have any suitable diameter and length. The size of the tube  102  can be selected to provide a filtering area, which based on the type of filter media  108 , suitable for the use for filtering a type and flow rate of fluid. In some embodiments, the tube  102  may have a length ranging from about 250 millimeters (mm) to about 3000 mm, or between about 500 mm and about 2000 mm. In some embodiments, a radius, r, of tube  102  may range from about 8 mm to about 120 mm, or from about 16 mm to about 80 mm. 
     The tube  102  may be made of any suitable material that has the proper structural strength and/or is inert to the fluids being filtered. In some embodiments, the tube  102  can be made of metals or alloys (e.g., steel, stainless steel, etc.), a composite material, polymers (e.g. polypropylene, polyvinylidene fluoride (PVDF), etc.), polymer coated or lined metal (e.g., a rubber lined vessel), or the like. In some embodiments, the tube  102  can be formed from a plastic such as polypropylene. When the tube  102  is formed from plastic, as may be needed when working with certain fluids such as corrosive solutions, the structural strength of the material can be an issue. This can create unique challenges for the designs of the self-cleaning filter  100  and the tube  102  based on certain factors such as when the size of the tube  102  is increased, the operating temperature increases, and/or the pressure differentials increases. The configurations of the filters as disclosed herein can then be used to allow for the filters to be scaled up while still maintaining the structural integrity needed for various operating conditions. 
     The central opening in the tube can define a chamber  106  positioned within tube  102 , where the chamber  106  can be in fluid communication with perforations  104 . The chamber  106  may extend along the length of tube  102 . The chamber  106  serves as a fluid passageway for fluids during filtering and cleaning, where the chamber may fill with filtered liquid during operation of self-cleaning filter  100  and a gas during cleaning of the self-cleaning filter  100 . 
     The filter media  108  may be positioned concentrically about/around the tube  102  and may extend along the length of the tube  102 . The filter media  108  serves to remove one or more materials within a fluid flow as the fluid flows through the filter media  108 . The filter media  108  may be a flexible material capable of being formed into tubes, sheets, and/or rolls. Examples of such materials can include, but are not limited to, paper, polypropylene, cellulose, polytetrafluoroethylene, tetrafluoroethylene, and other synthetic materials. The porosity and/or thickness of the filter sheet may be selected depending on the materials desired to be removed from the fluid. Examples of porosities may range from about 0.5 micron to about 200 microns. Examples of thicknesses of the filter media  108  may range from about 0.5 millimeter (mm) to about 3 millimeter. A surface area of the filter media  108  may range from about 0.05 to about 0.8, or from about 0.1 to about 0.5 meters squared (m 2 ) per meter-length of the filter media along an axial direction of the tube  102 . The filter media  108  (and filter  100 ) may be configured to receive fluid to be filtered at a flow rate ranging from 0 cubic meters per hour (m 3 /h) to 200 m 3 /h, or up to about 125 m 3 /h. The filter media  108  can have a diameter that is slightly larger than that of the tube  102  to allow the filter media to be placed over the tube  102  and any spacers  110 . In some embodiments, the filter media  108  can have a diameter between about 40 mm and about 250 mm, or from about 50 mm to about 210 mm. 
     One or more spacers  110  can be positioned around the tube  102  and between the filter media  108  and the tube  102 . The spacers  110  serve to shape the filter media  108  during use while allowing the filter media  108  to expand during a cleaning cycle of the self-cleaning filter  100 . The presence of additional material made by the filter media may allow for a void or space  112  to be formed between the tube  102  and the filter media  108  due to the presence of spacers  110  during cleaning cycle. During filtering, the spacers  110  allow filter media  108  to deform inward (during a flow-in of liquid to be filtered) into space  112 . During this process, a filter cake or layer can be formed on an outside of the filter media  108 . In some embodiments, the filter media  108  may adhere/stick to tube  102  during the in-flow of the liquid to be filtered. During the in-flow, filter cake may form on filter media  108 . In order to remove this filter cake, the filter media  108  may be popped/pushed outward quickly with a gas flow during the flow-out to remove or break off filter cake that has accumulated and adhered to filter media  108 , as described in more detail herein. 
     In some embodiments, the spacers  110  may be in the form of rods and extend along the length of tube  102  and filter media  108 . While shown as having a round cross-section, the spacers  110  can also have other cross-section shapes such as half-circle, triangular, square, or the like. In some embodiments, the spacers can have a diameter in a range from about 5 mm to about 40 mm, or from about 10 mm to about 25 mm. In some embodiments, a ratio of the diameter, s, of each spacer  110  to the inner diameter of the tube  102  may range from about 0.06:1 to about 0.9:1, or between about 0.06:1 to about 0.8:1. Any suitable number of spacers can be used around the tube  102 . Spacers  110  may be made of a material that is suitable for the environment in which the filter is used such as metals or alloys (e.g., steel, stainless steel, etc.), polymers (e.g. polypropylene, polyvinylidene fluoride (PVDF), etc.), polymer coated or lined metal (e.g., a rubber lined vessel), or the like. In some embodiments, the spacers  110  can be formed from any of the materials used to form the tube  102 , and in some embodiments, the spacers can be formed using the same materials as the tube  102 . 
       FIGS. 2A-2D  illustrate a self-cleaning filter  200  with a single tube  202  (“tube  202 ”). The tube  202  may be the same or similar to the tube described with respect to  FIGS. 1A and 1B , and the size and materials can be used with tube  202 . The self-cleaning filter  200  can be similar to the self-cleaning filter  100 , with the exception of the presence of a reinforcement core  214  and/or additional spacers  210 , and like components can be the same or similar to those described with respect to the self-cleaning filter  100 . 
     A chamber  206  may be formed and defined by an inner surface of the tube  202  and an outer surface of the reinforcement core  214 . The chamber  206  is in fluid communication with the perforations  204  within the tube  202 . The chamber  206  may include free space/volume within the tube  202  that is not occupied by a reinforcement core  214 . The chamber  206  may extend along the length of tube  202 , and may fill with filtered liquid during a filtering operation of self-cleaning filter  200 . In some embodiments, the reinforcement core  214  may reduce the interior volume of the tube  202  by an amount of at least about 10%, 20%, 30%, 40%, or 50%. In some embodiments, the reinforcement core  214  may reduce the interior volume of the tube  202  by an amount of equal to or less than 99%, 95%, 90%, 80%, or 70%. In some embodiments, the reinforcement core  214  may reduce the interior volume of the tube  202  by an amount between any of the lower amounts and any of the upper amounts. 
     The filter media  208  may be positioned concentrically about/around tube  202  and may extend along the length of tube  202 . The filter media  208  can include any of the filter media described with respect to the self-cleaning filter  100 . A surface area of the filter media  108  may range from about 0.05 to about 0.8, or from about 0.1 to about 0.5 meters squared (m 2 ) per meter-length of the filter media along an axial direction of the tube  102 . The filter media  108  (and filter  100 ) may be configured to receive fluid to be filtered at a flow rate ranging from 0 cubic meters per hour (m 3 /h) to 200 m 3 /h, or up to about 125 m 3 /h. 
     As with the filter media  208 , the spacers  210  can be the same or similar to the spacers  110 , and any of the spacers described with respect to the self-cleaning filter  100  can be used with the self-cleaning filter  200 . Similarly, the tube  202  can be the same or similar to the tube  102 , including any of the materials of construction and sizes as described above. 
     As shown, the self-cleaning filter  200  can include a reinforcement core  214 . The reinforcement core  214  can serve a number of functions including helping to reduce the total volume of the chamber  206  as well as providing reinforcement within the tube  202  to provide structural support during use in a filtering process. The reinforcement core  214  (“core  214 ”) may be made of any suitable material, including those that are inert to the fluid being filtered. In some embodiments, the reinforcement core  214  can be formed from metals or alloys (e.g., steel, stainless steel, etc.), a composite material, polymers (e.g. polypropylene, polyvinylidene fluoride (PVDF), etc.), polymer coated or lined metal (e.g., a rubber coated materials), or the like. The reinforcement core  214  may be positioned concentrically within tube  202  and may extend partially or entirely along the length of tube  202 , as shown on  FIG. 2C . 
     In some embodiments, the reinforcement core  214  may be positioned within the chamber  206  to reduce the volume or free space within the chamber  206 . A reduction in the amount of free space in the chamber  206  can reduce the amount and/or volume of a gas needed to expand the filter media during a cleaning process, as described in more detail herein. 
     The reinforcement core  214  may also include support portions  216  that extend outwards from the center of the tube  202  and contact the interior of the tube  202  to support tube  202  (e.g., prevent deformation of tube  202  during in-flow (filtering) of liquid or out-flow-out (e.g., self-cleaning) of gas). The support portions  216  and the spacers  210  can have any relative alignments around the perimeter of the tube  202 . In some embodiments, the segments  218  of tube  202  may be positioned between support portions  216  and spacers  210 , such that the segments  218  can be radially aligned with the spacers  210 . This configuration may allow the spacers  210  to be supported by the segments  218  during use. However, this alignment is optional and not necessary in all embodiments 
     The reinforcement core  214  may include recessions  220  positioned between the support portions  216 . The recessions  220  may extend lengthwise along the reinforcement core  214  and may provide fluid flow pathways that fill with filtered liquid as liquid passes through the filter media  208  and the perforations  204 . Also, the reinforcement core  214  may include a central passage  222  extending lengthwise through a center of the reinforcement core  214 . During use, the filtered liquid can enter the passage  222  via an inlet  223  positioned at an end  225  (a bottom) of the reinforcement core  214 , as shown on  FIGS. 2C and 2D . After the filtered fluid enters the passage  222 , the filtered fluid may exit the passage  222  via an outlet  227  into a receptacle for filtered fluid, as shown on  FIG. 2B . 
       FIG. 3A  illustrates a top view of a filter media  301 . The filter media  301  may be a particular embodiment of the filter media  108  or the filter media  208  during the flow-in period (filtering period). As shown, as a fluid enters the filter media  301  from an exterior of the self-cleaning filter and into the interior of the tube, the filter media  301  moves/flexes inward due to the flow/pressure of the fluid being filtered, and the filter media  301  may contact and be biased towards an outside surface of tube  303  and/or spacer  310  that may include the tube  102  or  202 , as shown. A space  312  can be formed between the spacer, the exterior surface of the tube, and the inner surface of the filter media  301 . The flow of entering fluid during a filtering process is depicted by the arrow  300 . The spacer  310  may be a particular implementation of the spacer  110  or the spacer  210 . The space  312  may be a particular implementation of space  112  or  212 . 
       FIG. 3B  illustrates a top view of filter media  301  during the out-flow period (e.g., during a self-cleaning period or process) after the in-flow period shown on  FIG. 3A . In this process, a gas can be introduced into an interior of the tube and flow outwards through the filter media. As shown, as a gas (e.g., a purging gas, a cleansing gas, etc.) pressurizes the filter media  301 , the filter media  301  moves/flexes outward from the space  312  (due to the flow/pressure of the gas exiting the tube) and may rebound or move back substantially to a pre-filtering/initial physical form. The flow of exiting gas is depicted by the arrow  302 . The self-cleaning period allows for the gas to exit the filter media the tube, thereby flexing (in an outward direction) the filter media  301 . This flexing results in a removal/dropping of any filter cake that has formed on and/or adhered to filter media  301 . 
       FIGS. 4A and 4B  illustrate an embodiment of a self-cleaning filter  400  with a single tube  402  (“tube  402 ”). The self-cleaning filter  400  is similar to the self-cleaning filters  100  and  200 , and similar components can be the same or similar to the components described with respect to the self-cleaning filters  100  and  200 . The main difference between the self-cleaning filter  400  and the self-cleaning filters  100  and  200  is the volume reducer  414 . 
     The tube  402  may be the same or similar to the tubes described with respect to the self-cleaning filters  100  and  200 . In some embodiments, the tube  402  may have a length ranging from about 250 millimeters (mm) to about 3000 mm, or between about 500 mm and about 2000 mm. In some embodiments, a radius, r, of tube  402  may range from about 50 mm to about 300 mm, or from about 60 mm to about 200 mm. The tube  402  may be perforated as described with respect to the tubes described with respect to the self-cleaning filters  100  and  200 . 
     The chamber  406  can be defined by an inner surface of the tube  402  and formed within tube  402 . The chamber  406  is in fluid communication with an exterior of the tube  402  and filter media  408  via the perforations  404 . The chamber  406  may extend along the length of the tube  402 , and may include free or unoccupied space within the tube  402 . 
     The filter media  408  can be the same as the filter media described with respect to the self-cleaning filter  100  or the self-cleaning filter  200 . The filter media  408  may be positioned concentrically about/around tube  402  and may extend along the length of tube  402 . The filter media  408  can have a diameter that is slightly larger than that of the tube to allow the filter media to be placed over the tube  402  and any spacers  410 . In some embodiments, the filter media  408  can have a diameter between about 150 mm to about 500 mm, or from about 165 mm to about 480 mm. A surface area of the filter media  408  may range from about 0.2 to about 1.5, or from about 0.4 to about 1.3 meters squared (m 2 ) per meter-length of the filter media along an axial direction of the tube  402 . The filter media  408  may be configured to receive fluid to be filtered at a flow rate ranging from 0 cubic meters per hour (m 3 /h) to 200 m 3 /h, or up to about 125 m 3 /h. 
     The spacers  410  can be the same as the spacers described with respect to the self-cleaning filter  100  or the self-cleaning filter  200 . In some embodiments, the spacers  410  can have a diameter in a range from about 10 mm to about 60 mm, or from about 20 mm to about 40 mm. In some embodiments, a ratio of the diameter, s, of each spacer  110  to the inner diameter of the tube  102  may range from about 0.03:1 to about 0.8:1, or between about 0.05:1 to about 0.5:1 
     As shown, the self-cleaning filter  400  can include a volume reducer  414 . The volume reducer  414  is similar to the reinforcement core described herein in that the volume reducer  414  serves to reduce the volume within the chamber  406 . The volume reducer  414  may be of a cylindrical shape and may partially or fully extend along the length of tube  402 , similar to the reinforcement core  214  as shown on  FIG. 2C . The volume reducer  414 , similar to the reinforcement core  214 , also reduces a volume of free space that can be occupied by a fluid. The volume reducer  414  may include a passage  416  passing therethrough. In some embodiments, the volume reducer  414  may reduce the interior volume of the chamber  406  by an amount of at least about 10%, 20%, 30%, 40%, or 50%. In some embodiments, the volume reducer  414  may reduce the interior volume of the chamber  406  by an amount of equal to or less than 99%, 95%, 90%, 80%, or 70%. In some embodiments, the volume reducer  414  may reduce the interior volume of the chamber  406  by an amount between any of the lower amounts and any of the upper amounts. 
     In use of the self-cleaning filter  400 , liquids containing contaminants can pass through filter media  408  from an exterior of the self-cleaning filter  400  into an interior of the tube  402  via the perforations  404  of tube  402 , thereby filtering at least a portion of the contaminants as the fluid passes through the filter media  408 . The filtered fluid can pass between the interior of the tube  402  and an exterior of the volume reducer  414  (see the arrow  413  in  FIG. 4C ). The filtered liquid can then enter (see the arrow  413 ) the passage  416  (e.g., a tube) via an inlet  418  (see  FIGS. 4B and 4C ). The filtered liquid may then pass through the passage  416  and can exit (see arrow  415 ) passage  416  via an outlet  420 , which can be in fluid communication with a receptacle for holding the filtered liquid. The end  422  (bottom end) of the volume reducer  414  may be sealed except for the inlet  418  and the passage  416 . A space  424  (internal bore or internal chamber) within an interior of the volume reducer  414  and around/about passage  416  can be arranged with a filter housing using appropriate seals and the like to remain free of any liquid. This allows for a reduction in a volume/free space within tube  402 . 
     As shown in  FIGS. 4A-4C , the volume reducer  414  is placed within the tube  402 , but may not contact an inner surface of the tube  402 . The volume reducer  414  can be retained in position by one or more components of a filter housing, as described in more detail herein. Appropriate seals and connections can be present as part of the filter housing to allow the fluid to flow along predetermined flow pathways. 
       FIGS. 5A-5C  illustrate self-cleaning filter  500  with multiple tubes  102 , as described above (see  FIGS. 1A and 1B ). The self-cleaning filter  500  has components similar to those described with respect to the self-cleaning filters  100 ,  200 ,  400 , and the same or similar components may have the same reference numbers. In some embodiments, multiple tubes  102  (e.g., a plurality of tubes  102 ) may be positioned about or around a passage  516  through a flow tube. The flow tube  516  may extend partially along the length of the tubes  102 , as shown on  FIG. 5C . In some embodiments, the flow tube  516  can extend along the entire length of the tubes, and one or more opening can be disposed in an end of the flow tube  516  to provide a fluid pathway into an interior of the flow tube  516 . The use of multiple tubes  102  may provide the spacing to allow the filter media to contract and expand in response to the filtering process and cleaning process. As shown, the multiple tubes  102  may take the place of spacers in this embodiment as the outer profile of the tubes  102  serves as the spacers. 
     When multiple tubes  102  are present, the filter media  508  may be positioned concentrically about/around the tubes  102  and may extend along the length of the tubes  102 . In some embodiments, the tube  102  may have a length ranging from about 250 millimeters (mm) to about 3000 mm, or between about 500 mm and about 2500 mm. In some embodiments, a radius, r, of tube  102  may range from about 8 mm to about 80 mm, or from about 10 mm to about 65 mm. 
     The filter media  508  may be the same or similar to any of the filter media as described herein. In some embodiments, the filter media  508  (and filter  500 ) may be configured to receive fluid to be filtered at a flow rate ranging from 0 m 3 /h to 150 m 3 /h. A surface area of the filter media  508  may range from about 0.05 to about 1.5, or from about 0.1 to about 1.2 meters squared (m 2 ) per meter-length of the filter media along an axial direction of the tube  102 . The filter media  508  can have a diameter that is slightly larger than that of the tube to allow the filter media to be placed over the plurality of tubes  102 . In some embodiments, the filter media  508  can have a diameter between about 40 mm to about 500 mm, or from about 50 mm to about 375 mm. 
     During a filtering process, contaminated liquid can pass through from an exterior of the self-cleaning filter  500 , through the filter media  508 , and through the perforations  104  of tubes  102  and/or into a space between the tubes  102  and an exterior of the flow tube  516 . The filtered liquid can pass to an end of the flow tube  516  and enter (see arrows  513 ) the interior of the flow tube  516  via an inlet  518 , as shown on  FIGS. 5B and 5C . In some embodiments, the flow tube  516  can extend the entire length of the tubes  102 , and one or more openings can be present to allow the filtered fluid to enter the interior of the flow tube  516 . The filtered liquid may then pass through the flow tube  516  and exit (see arrow  515 ) the flow tube  516  via an outlet  520 , which can be in fluid communication with a receptacle or flow pathway for holding the filtered liquid.  FIG. 5B  illustrates the end  522  (bottom end) of the flow tube  516 . The self-cleaning filter  500  can be retained in position within a filter housing by one or more components of a filter housing, and appropriate seals and connections can be present as part of the filter housing to allow the fluid to flow along predetermined flow pathways. 
       FIGS. 6A and 6B  illustrate a self-cleaning filter  600  with multiple tubes  202  including cores  214 . The cores  214  can be the same or similar to the cores  214  described above (see  FIGS. 2A and 2B ). Further, the self-cleaning filter  600  having multiple tubes can be the same or similar to the self-cleaning filter  500  as described with respect to  FIGS. 5A-5C , and similar components can be the same or similar. The filter media  608  may be positioned concentrically about/around tubes  202  and may extend along the length of tubes  202 . The filter media  608  may be the same or similar to any of the filter media as described herein, including filter mediate  508 . The cores  214  can be positioned within one or more of the tubes, and in some embodiments, all of the tubes  202 . The cores  214  can serve to support the tubes  202  and/or reduce the interior volume within the tubes  202 . 
     During a cleaning process, a liquid containing one or more contaminants to be filtered can pass through filter media  608  to remove at least a portion of the one or more contaminants. When being used for filtering the fluid, the filter media  608  can contact and conform to the outer surface of the tubes  202 . The filtered liquid can pass into the tubes  202  via perforations  204  and/or into the space between the tubes and the flow tube  516 . The filtered liquid can then enter the flow tube  516  via an inlet  518 . The filtered liquid may then exit the flow tube  516  via an outlet  520 , which can be in fluid communication with a receptacle for holding the filtered liquid.  FIG. 6B  illustrates the end  522  (bottom end) of the flow tube  516 . The flow of liquid in this configuration is similar to the flow of liquid shown on  FIGS. 5A-5C . 
       FIG. 7A  illustrates a top, cross-section view of filter media  708 . Filter media  708  may be a particular implementation of filter media  508  or  608  during the in-flow period or process, and the filter media  708  can include any of the filter media materials as described herein. As shown, as a fluid enters filter media  708 , filter media  708  moves/flexes inward into space  703  due to flow/pressure of the fluid being filtered and may conform to and engage an outside surface of tubes  702  that may include tubes  102  or  202 , as shown. The direction of flow of the entering fluid is depicted by arrow  300 . 
       FIG. 7B  illustrates a top, cross-sectional view of filter media  708  during the out-flow period (e.g., filter self-cleaning period). As shown, as a gas (e.g., a purging/cleansing gas) exits filter media  708 , filter media  708  moves/flexes outward from space  703  due to flow/pressure of the exiting gas and move back substantially to a pre-filtering/initial physical form. The force to move the filter media  708  back to the initial form can be provided by the pressure drop across the filter media supplied by the gas. The flow direction of exiting gas is depicted by arrow  302  in  FIG. 7B . The self-cleaning period allows for the gas to exit filter media  708 , thereby flexing (in an outward direction) filter media  708 . This flexing can result in a removal of at least a portion of any filter cake that has adhered to filter media  708 . The removal process can be enhanced by first drying the filter cake, as described in more detail herein. 
       FIGS. 8A and 8B  illustrate an embodiment of a self-cleaning filter  800  with multiple tubes  102  and a volume reducer  414 . The components of the self-cleaning filter  800  can be the same or similar to those described herein, for example as described above (e.g., see  FIGS. 1A, 1B, 4A, 4B, and 4C ). In some embodiments, the tube  102  may have a length ranging from about 250 millimeters (mm) to about 3000 mm, or between about 500 mm and about 2500 mm. In some embodiments, a radius, r, of tubes  102  may range from about 5 mm to about 60 mm, or from about 10 mm to about 45 mm. A surface area of the filter media  808  may range from about 0.2 to about 3, or from about 0.4 to about 2.25 meters squared (m 2 ) per meter-length of the filter media along an axial direction of the tube  102 . The filter media  808  may be configured to receive fluid to be filtered at a flow rate ranging from 0 cubic meters per hour (m 3 /h) to 300 m 3 /h, or up to about 250 m 3 /h. The filter media  808  can have a diameter that is slightly larger than that of the tube to allow the filter media to be placed over the tubes  102 . In some embodiments, the filter media  808  can have a diameter between about 100 mm to about 750 mm, or from about 130 mm to about 680 mm. While a number of tubes  102  are shown, the number of tubes  102  an vary between about 5 tubes and about 40 tubes, between about 10 tubes and about 30 tubes, or between about 15 tubes and about 25 tubes, depending on the surface area needed and the overall size of the filter. 
     In use, a liquid comprising one or more contaminants can pass through the filter media  808  from an exterior of the self-cleaning filter  800  into the one or more tubes  102  and/or a space between the one or more tubes  102  and an exterior of the volume reducer  414  via the perforations  104  of the tubes  102 . The filtered liquid enters the flow tube  416  via an inlet  418 , shown on  FIGS. 4B and 4C . The filtered liquid may then exit (see arrow  415  in  FIG. 4C ) the flow tube  416  via an outlet  420 , which can be in fluid communication with a receptacle for holding the filtered liquid. The end  422  (bottom end) of the volume reducer  414  may be sealed except for the inlet  418  the flow tube passage  416 . The space  424  within the volume reducer  414  and around/about the flow tube  416  can remain free of any liquid based on being retained in a filter housing. This allows for a reduction in a volume/free space within the self-cleaning filter  800 . 
       FIG. 8C  illustrates a top view of filter media  808  during an out-flow period (filter self-cleaning period) after an in-flow period shown on  FIG. 8D . As shown, as a gas (purging/cleansing gas) exits filter media  808 , filter media  808  moves/flexes outward from space  809  due to flow/pressure of the gas exiting and may rebound or move back substantially to a pre-filtering/initial physical form. The flow of exiting gas is depicted by arrow  302 . The self-cleaning period allows for the gas to exit the filter media  808 , thereby flexing in an outward direction the filter media  808 . This flexing can result in a removal of at least a portion of any filter cake that has adhered to filter media  808 . 
       FIG. 8D  illustrates a top view of a filter media  808  during the flow-in period (filtering period). As shown, as a fluid enters filter media  808 , filter media  808  moves/flexes inward into space  809  due to flow/pressure of the fluid being filtered and may conform to an outside surface of tubes  102 , as shown. The flow of entering fluid is depicted by arrow  300 . 
       FIG. 9  illustrates a schematic flow diagram of a filter system  950  according to some embodiments. As illustrated, a process  952  using a fluid can provide a rich fluid containing particles or elements to be filtered out of the fluid to an optional feed tank  954 , and then to a filtering vessel  900 . The process  952  can comprise any type of process that uses a liquid and results in particles or components within the fluid that can be filtered. Exemplary processes can include fluid units for oil and gas, power generation, water and waste water, battery production, food processing and refining, metals plating and galvanizing, chemical processing, and other industrial processes. The filtering vessel  900  can include any of the self-cleaning filter elements as described herein, and suitable arrangements and components of the filtering vessel  900  are described in more detail herein. 
     When present, the feed tank  954  can serve as an intermediate holding tank prior to the rich fluid being passed to the filtering vessel  900 . The feed tank  954  can serve as a surge tank and/or as a chemicals tank such that one or more chemicals can be dosed into the rich fluid and allowed to react prior to the rich fluid passing to the filtering vessel  900 . In some aspects, a filtrate such as a powdered material used to form a filter cake on the filter element for use in the filtering process can be introduced into the feed tank  954  after the filter cleaning process, as described in more detail herein. In some embodiments, the feed tank can be used to contain a chemical or solution to clean the filter element within the filtering vessel  900 . For example, the feed tank  954  can contain water, a cleaning solution (e.g., soap, de-scaling agents, etc.), or the like to remove any remaining contaminants from the filter element, piping, sensors, and valves as part of the self cleaning process. 
     In order to prevent settling of the components in the feed tank  954 , a mixing device or agitator can be installed within the feed tank  954  in some embodiments to keep the rich fluid in the tank well mixed. When additional chemicals are added into the fluid in the feed tank  954 , the mixer or agitator can be used to provide a mixed solution to ensure a full reaction between the chemicals and the components in the rich fluid prior to the rich fluid passing to the filtering vessel  900 . Examples of reactants and conditions are provided herein. 
     A gas source  956  can be fluidly coupled to the filtering vessel  900  to provide the gas used to remove the filtered solids from the filter element. For example, the gas source  956  can provide the gas for the back-pulse. While illustrated as a vessel, the gas source  956  can include any combination of a compressed gas source (e.g., a pressure tank, etc.), a compressor, a fan, a blower, or the like. Further, the gas can comprise any suitable gas for the process  952 . In some aspects, the gas can comprise air. In other aspects, the gas may comprise an inert gas such as nitrogen, argon, or the like when reactive gases such as flammable gases are present within the filtering vessel  900 . While shown as supplying air to a fluid line between the process  952  and/or the feed tank  954 , the gas source  956  can also be in direct fluid communication with the filtering vessel  900 . 
     In some embodiments, an optional buffer tank  958  can be in fluid communication with the filtering vessel  900  and/or one or more additional components such as the feed tank  954  or disposed between the process  952  and the feed tank  954 . The buffer tank  958  can serve to store some amount of the process fluid and allow for some amount of pressure buffering within the system. For example, the buffer tank  958  can contain a gas and/or contain the process fluid in a bladder or other expandable container. The buffer tank can then serve to reduce pressure forces or shocks within the system during the filtering and cleaning process. For example, when fluid flow stops (e.g., creating a water hammer effect, etc.) and/or the gas is introduced into the system, the buffer tank  958  can serve to reduce the peak pressure loads to protect the various components of the system. In some embodiments, the buffer tank  958  can help to provide a pressure buffer when the components of the system are vertically separated. For example, when the filtering vessel  900  is disposed below the process  952 , the buffer tank  958  can serve to buffer the pressure between the two processes and aid in the startup process after a self-cleaning cycle. In some embodiments, the buffer tank  958  may not be present, and the feed tank  954  may serve to provide a buffering function within the system. 
     During a normal filtering operation, the rich process fluid can be passed from the process  952  to the filtering vessel  900 , which can comprise one or more vessels with filter assemblies arranged in parallel or series. When a feed tank  954  is present, the rich process fluid can pass to the feed tank  954  before passing to the filtering vessel  900 . The rich process fluid can then be filtered within the filtering vessel  900  to capture the filtered particles from the fluid, and the filtered, clean process fluid can pass back to the process  952 . This process can continue so long as the filtering vessel  900  has filtering capacity. Various measurements and sensors can be used within the filtering vessel  900  to determine the filtering capacity, including sensors such as pressure sensors, position sensors, fluid level detectors, and the like. For example, the filtering capacity can be determined by a pressure drop across the filter element within the filtering vessel  900 , though other sensors and sensed process conditions can also be used to determine the filtering capacity of the filter element. 
     When the filter element needs to be cleaned, a self-cleaning cycle can be initiated. During the self-cleaning cycle, the process fluid passing to the filtering vessel  900  may be stopped. As described in more detail here, the process fluids within the filtering assembly  900  can first be drained from the filtering vessel  900 . The process fluid can be recovered and passed back to the process to avoid loss of the process fluids. In some embodiments, the process fluid can be passed into the feed tank  954  to store the fluid from the filtering vessel during the cleaning cycle. 
     Once the fluids are removed from the filtering vessel  900 , a drying gas can be introduced into the filtering vessel to dry the filtered solids on the filter element. Once dried, a back-pressure pulse or flow of gas can be supplied from the gas source  956  to break the dried filter materials loose from the filter assembly and cause the dried materials to fall to a bottom of the filtering vessel  900 . A valve or flap in the lower portion of the filtering vessel  900  can then be actuated to allow the dried solids to pass out of the filtering vessel  900 . 
     In some embodiments, the filter element can use a filtrate material used to form a filter cake on the filter element. The filtrate material can comprise any suitable material that can form a filter cake that is then used to filter the particulates or components from the process fluid. The filtrate is generally a particulate material (e.g., a powder) that is capable of being filtered on filter element to form the filter cake while being relatively porous to allow for flow of the process fluid through the resulting filter cake. Examples of filtrate can include diatomaceous earth, perlite and/or other mineral based filter media powders, and the like. 
     The filtrate can be removed with the filtered materials and be can be replaced prior to starting the filtering process. In order to introduce the filtrate, the process fluid can initially be circulated between the feed tank  954  and the filtering vessel  900  prior to introducing process fluids from the process  952 . The filtrate can be introduced into the fluid in the feed tank  954 , and an agitator or mixer can be used to form a mixture of the filtrate and the process fluids. The mixture can then be passed through the filtering assembly  900  where the filtrate can form a filter cake on the filter element in the filtering assembly  900 . The clean or filtered process fluid can be returned to the feed tank  954  until the filtrate is filtered on the filter element to form the filter cake. The process fluid can then be introduced into the filter assembly  900  directly or through the feed tank  954  to continue the normal filtering process. The filtering and self-cleaning cycles can be continued and repeated in order to maintain a desired level of filtering of the process fluids. 
     Within the self-cleaning process, the filter element can be cleaned as described herein, and the process fluid can be re-introduced into the filtering vessel after the self-cleaning. In some aspects, the filter element and the associated piping, valves, and/or sensors may be cleaned to remove any residual contaminants such as scale, residual filter particles, residual filtrate, and the like. For example, the filter element can build up scale over time that may not be removed in the self-cleaning process, and the scale can contribute to an initial backpressure across the filter element that can limit the useful filtering time of the filter element. In order to remove any build up on the filter element and associated equipment, a chemical solution such as hot water, cleaning solution, scale remover, etc. can be circulated through the filtering vessel after the self-cleaning process and before the process fluid is reintroduced into the filtering vessel. In some embodiments, the cleaning fluid can be included in the feed tank and used to circulate between the feed tank and the filtering vessel to clean the filter element and the filtering vessel and associated equipment. Once circulated and cleaned, the filtering vessel can be returned to use to filter the process fluids. The filter element cleaning may occur periodically or as needed based on contaminant buildup on the filter element and associated equipment, for example, as measured by a backpressure reading or pressure drop in the filtering vessel. 
     Having described the general components and operation of the system, embodiments of the operation of the filtering vessel  900  will now be described.  FIG. 10A  illustrates an embodiment of the filtering vessel  900 . The vessel  900  is configured to contain a self-cleaning filter element as described above, and any of the embodiments of the filter element as described herein can be used in the vessel  900 . The vessel  900  may be a container configured to withstand high pressures and high temperatures during filtering operations. The vessel  900  may be a sealed/pressurized vessel. Depending on the operating conditions, the vessel  900  can be constructed of a suitable material capable of withstanding the temperatures, pressures, and chemicals encountered in a filtering process. In some embodiments, the vessel  900  may be formed from metals or alloys (e.g., steel, stainless steel, etc.), a composite material, polymers (e.g. polypropylene, polyvinylidene fluoride (PVDF), etc.), polymer coated or lined metal (e.g., a rubber lined vessel), or the like and can be configured to withstand high pressures and high temperatures during filtering operations. 
     In some embodiments, the vessel  900  may include a filtered fluid outlet  902  (“outlet  902 ”), which can be or can be fluidly coupled to, a valve at a first end (top) of the vessel  900 , a feed inlet  904 , which can be or can be fluidly coupled to, a valve at a second end (bottom), and a filter cake disposal valve  906 . A filter cake discharge chute  908  may be adjacent to the disposal valve  906 . The vessel  900  may include a filter  914  that may be a particular implementation of a filter as discussed above (e.g., filter  200 ,  500 ,  600 , or  800 ). The vessel  900  may also include filtered fluid flow tube  910  (“flow tube  910 ”) to receive filtered liquid via one or more inlets  912 . The flow tube  910  may be a particular implementation of any of the embodiments of a core or a volume reducer as described herein. It should be noted that the flow tube  910  may include inlets  912  (e.g., side inlets in  FIG. 10A ) or inlet  223  (e.g., bottom inlet in  FIG. 2D ) or  418  (e.g., bottom inlet in  FIG. 4B ). 
     In some embodiments a drain tube  907  can be present within the filtering vessel  900 . The drain tube  907  can be coupled to the feed inlet  904  and provide a sealed fluid pathway between the feed inlet  904  and a lower portion of the filtering vessel  900  above the disposal valve  906 . The drain tube  907  allows the fluid within the filtering vessel  900  to be nearly completely drained from the filtering vessel  900  during a drying a filter cleaning process, as described in more detail herein. A second feed inlet  905  can be optionally present in the vessel  900  for use as a feed inlet or a drain outlet. The second inlet  905  may be useful for high flow operations where additional flow rate into and/or out of the vessel  900  is needed. 
     The filter can be retained within the vessel  900  using various retaining components. In some embodiments, the vessel  900  may include pinch points  916  between a first retaining ring  918  and first filter holder  920 , and between a second retaining ring  921  and a second filter holder  919 . The first retaining ring  918  can engage the first filter holder  920  with the filter media  922  disposed therebetween to retain the filter media  922  in position at a top of the filter. The second retaining ring  921  and the second filter holder  919  can be engaged with the filter media  922  disposed therebetween to retain the filter media  922  in position at the bottom of the filter. This engagement can retain the filter media  922  in position during use. 
     A cap can be retained on the vessel  900  using clamps or retaining bolts  923  that can be threaded into corresponding holes on a body of the vessel  900 . A seal can be disposed between the cap and the body to form a seal for the vessel  900 . The engagement of the cap with the body can compress the retaining rings  918 ,  921 , and the filter holders  919 ,  920 . In some embodiments, the first retaining ring  918  can threadedly engage the first filter holder  920 , and the second retaining ring  921  can threadedly engage the second filter holder  919  to form a filter assembly. The filter media  922  may be a particular implementation of a filter media, as described above. The vessel  900  may also include a gas inlet valve  924  that may be utilized for directing gas into vessel  900  for drying filter cake on the filter media  922 . The gas inlet valve  924  may also be utilized as a vent for pressurized fluid within the vessel  900 . A system controller  925  (e.g., a computer system) may include a processor, memory, and display and can be configured to operate the vessel  900  (e.g., opening or closing valves, detecting temperatures and pressures with sensors positioned in vessel  900 ). System controller  925  may be in signal communication with the vessel  900  (e.g., via a wired or wireless connection such as signal line  926 ). 
     During operation of the filter  914 , a liquid comprising one or more contaminants can be fed to vessel  900  via feed inlet  904 , or optionally, inlet  905 . The disposal valve  906  and the gas inlet  924  may remain closed. The vessel  900  may fill up with the liquid to be filtered. During this process and once the vessel  900  is full of the liquid to be filtered, the liquid can flow through the filter media  922  and through the filter  914  and into the flow tube  910 . At least a portion of the contaminants in the fluid can be filtered by the filter media  922  and begin to form a filter cake on an exterior surface of the filter media  922 , allowing the filtered fluid to pass into the filter. The flow tube  910  may be fluidly coupled to the outlet  902 . After entering the flow tube  910 , the clean, filtered fluid may exit filter  900  via outlet  902 , which can be or can be in fluid communication with, a valve. 
       FIG. 10B  illustrates filter cake  1000  accumulating on the filter media  922 . The direction of a flow of liquid is depicted by arrows  1002 . The liquid containing the one or more contaminants can enter vessel  900  via the inlet  904 , enter the filter  914  (e.g., after passing through the filter media  922  and perforations). After passing through filter  914 , the filtered liquid can flow into the flow tube  910  via the inlets  912 . The flow tube  910  receives the filtered liquid. The filtered liquid can flow out of the vessel  900  via outlet  902 . The flow rate through the vessel  900  can be controlled using one or more control valves and/or through a control of the pumping rate (e.g., the pump speed, etc.). A thickness of filter cake  1000  may correspond with a pressure differential between fluid pressure at inlet  904  and outlet  902 , where a thicker filter cake  1000  can be associated with a higher pressure differential. Once the differential pressure is detected to be above a threshold and/or after a threshold time period, the system controller  925  can cease the filtration process. 
     Once the filtration process is stopped, the self-cleaning cycle can be initiated. As a first step, the vessel  900  can be emptied of the liquid being filtered.  FIG. 10C  illustrates emptying of liquid from the vessel  900  after filtration is complete. The remaining clean liquid within the flow tube  910  can be directed to the outlet  902  (see arrow  901 ), and any unfiltered liquid remaining outside of the filter media  922  can be directed back into a feed tank through the feed inlet  904  (see arrows  903 ). It can be noted that a minor amount of filtered fluid retained in the filter media and/or flow tube  910  may pass back out of the filter media  922  and pass through the feed inlet  904  when the vessel  900  is being drained. A purge gas can be introduced into the vessel  900  via inlet  924  to assist with clearing any remaining fluid within vessel  900 . As the gas flows into the vessel  900 , any filtered liquid within the flow tube  910  can flows out through outlet  902 . Any unfiltered liquid outside of the filter media  922  within the vessel  900  can flow back into a feed tank through the inlet  904 . The use of the drain tube  907  can allow the fluid to be removed from slightly above the valve  906 . The fluid can be pumped out from the vessel  900  out of the inlet  904  and/or pulled by a suction or vacuum out of the inlet  904 . The suction or vacuum can be generated using any suitable process or device. In some embodiments, the suction or vacuum can be generated through the use of an eductor in fluid communication with the outlet to create suction at the outlet (e.g., at the drain tube  907 ). The use of suction along with the drain tube  907  can allow for the vessel  900  to be substantially emptied of liquids before the drying cycle begins. Once empty, the inlet  904  can be closed, for example, using a valve. 
     Once the vessel  900  is drained, the filter media  922  can have the wet filter cake disposed thereon within the vessel  900 . In order to limit the amount of material to be cleaned from the filter media  922 , the filter cake can be dried within the vessel  900  before being removed. In order to dry the filter cake  1000 , a drying gas can be passed into the vessel  900 .  FIG. 10D  illustrates the filter cake  1000  drying with a drying gas that is pumped into vessel  900  via inlet  924 . The gas is utilized to dry filter cake  1000  from filter media  922 . The gas may enter flow tube  910  via inlets  912  and may exit vessel  900  via outlet  902 . Vessel  900  remains pressurized during drying. 
     The gas used during the drying cycle can be any suitable gas. In some embodiments, air can be used as the drying gas if oxygen is not reactive with the chemicals in the filter cake. Otherwise, an inert gas such as nitrogen can be used. In order to dry the filter cake, the gas can be heated and/or dried prior to passing into the vessel  900 . For example, the gas can be heated to between 5° C. and 95° C. prior to passing into the vessel  900 . The temperature of the gas will depend on the materials used to form the filter and housing and/or the type of chemicals being filtered within the vessel  900 . The use of a heated and/or dried gas may improve the drying times for the filter cake. 
     Once dried, the filter cake  1000  can be removed from the filter media  922 .  FIG. 10E  illustrates the filter cake  1000  being removed from the filter media  922 . In order to remove the dried filter cake from the filter media  922 , the flow of the drying gas can be stopped. Any remaining gas pressure can be released via outlet  902 . Depending on the gas composition, a purge gas can be optionally used to purge the vessel  900  if needed. The valve  906  can be opened in order to collect the dried filter cake when removed from the filter media  922 . When removed, the pieces of the filter cake  1000  can fall from the filter media  922  and pass through the valve  906  (open position) for collection and subsequent disposal. 
     In order to remove the dried filter cake from the filter media  922 , a back-pulse of a gas can be used to expand the filter media  922 . The back-pulse can be provided by a gas source such as a compressed gas source (e.g., a pressure tank, etc.), a compressor, a fan, a blower, or the like.  FIG. 10F  illustrates a flow of gas entering the vessel  900  via the outlet  902  depicted by arrows  1004 . This back pulse flow of gas causes the filter media  922  to be restored to the original shape as discussed herein. For example, the filter media  922  may conform to the shape of the tube(s) and/or spacers as described above during the filtration process. The filter cake can also conform to the shape of the filter media  922  during the filtration process. By back-pulsing the filter media  922 , the filter media  922  can expand outward and change shape. The change in shape may cause the dried filter cake to break into pieces and become dislodged from the filter media  922 . 
     The amount of the gas used for the back-pulse can depend on the need to provide a pressure differential within the interior of the filter media  922 . As the volume within the filter assembly increases, a large amount of gas is needed in order to provide a given amount of pressure differential, which would need to be supplied by a larger gas reservoir (e.g., a pressure tank, etc.), fan, compressor, or the like. This can lead to a correspondingly larger compressor and associated equipment. In order to reduce the amount of gas needed for the back-pulse, a core or volume reducer as described herein can be used. The core or volume reducer can reduce the total amount of space or volume that needs to be pressurized with the gas in order to back-pulse the filter media  922 . This can then reduce the size of the equipment needed to provide the back-pulse. 
     Once dislodged, the dried filter cake pieces can then pass downwards through the valve  906  into a receptacle. After this back pulse flow of gas, the filtration and cleaning process is complete, and the valve  906  can be closed. Vessel  900  may be ready for a subsequent filtration cycle for another batch of contaminated liquid. Thus, the self-cleaning cycle can be used to reduce the total amount of waste generated from the system by drying the filter cake within the vessel so that only a dried filter cake is removed from the system. Further, the filter cake can be removed without the need for the removal of the entire self-cleaning filter assembly and without requiring users to handle the wet, and potentially harmful, filter cake materials. 
     Within the system illustrated in  FIG. 10A-10F , a filtering system can comprise a plurality of vessels  900  arranged in parallel. This allows the system to continue to filter the liquids through at least one vessel  900  while one or more additional vessels are placed into the self-cleaning process. In some embodiments, a filtering system can comprise 2-10 vessels, with at least 2 vessels fluidly connected in parallel. 
     Another embodiment of a filtering system is shown in  FIGS. 11A-11F .  FIG. 11A  illustrates a filtering vessel  1100 , which can be similar to the vessel  900 . The vessel  1100  may be formed from metals or alloys (e.g., steel, stainless steel, etc.), a composite material, polymers (e.g. polypropylene, polyvinylidene fluoride (PVDF), etc.), polymer coated or lined metal (e.g., a rubber lined vessel), or the like and can be configured to withstand high pressures and high temperatures during filtering operations. The vessel  1100  may be a sealed vessel except for the filtered fluid outlet  902  at a first end (top) of the vessel  1100 , a feed inlet  904  at a second end (bottom), and a filter cake disposal valve  906 . A filter cake discharge chute  908  may be adjacent (below) to the valve  906 . The vessel  1100  may include a self-cleaning filter including any of those described herein. The vessel  1100  may include a chamber  106  for receiving filtered fluid. In some embodiments, the filter may not include a flow tube to collect fluids from a lower portion of the filter to pass the fluids out of the filtered fluid outlet  902 . 
     The vessel  1100  may include the filter media coupled in the same manner as described with respect to the vessel  900 . The vessel  1100  may also include gas inlet  924 , which can be coupled to a valve, that may be utilized for directing gas into the vessel  1100  for drying the filter cake on the filter media  108 . The gas inlet  924  may also be utilized as a vent for pressurized fluid within the vessel  1100  in portions of the filtering and/or self-cleaning cycles. A system controller  925  (e.g., a computer system as described in more detail herein) may include a display and can be configured to operate the vessel  1100  (e.g., opening or closing valves, detecting temperatures and pressures with sensors positioned in the vessel  1100 ). 
     During operation of the filter system, a liquid comprising one or more contaminants can be fed to the vessel  1100  via the feed inlet  904 . The disposal valve  906  and the gas inlet  924 , and optional inlet  905 , may remain closed during the filtration process. In some embodiments, the gas inlet  924  can optionally be used to vent any gas in the vessel  1100  while the vessel  1100  is initially filling. The vessel  1100  may fill up completely with the liquid to be filtered, including a portion of the liquid that passes through the filter media to fill the filter. 
     After the vessel  1100  is full of liquid to be filtered, the liquid can be circulated through the vessel  1100  such that the liquid flows through filter and into the chamber  106 . The chamber  106  may be fluidly coupled to the outlet  902 . After entering the chamber  106 , clean fluid may exit the vessel  1100  via the outlet  902 . The flow of fluid can be controlled by an outlet valve, a pumping speed (e.g., thereby controlling the pump speed), or a combination thereof. 
     During the filtration process, a filter cake  1000  can form on an outer surface of the filtration medium.  FIG. 11B  illustrates the filter cake  1000  accumulating on the filter media  108 . The direction of a flow of the liquid is depicted by the arrows  1002 . The contaminated liquid enters the vessel  1100  via the inlet  904  and/or optional inlet  905 , enters the filter (passing through filter media  108  and perforations  104 ). After passing into the filter, the liquid is clean (e.g. having at least a portion of the contaminants removed by being filtered) and can flow into the chamber  106  via perforations  104  and filter media  108 . The chamber  106  receives the filtered liquid. The filtered liquid can flow out of the vessel via the outlet  902 . A thickness of filter cake  1000  may correspond with a pressure differential between fluid pressure at inlet  904  and outlet  902 . The thicker the filter cake  1000  is, the larger the pressure differential may be across the filter cake and filtration media. Once a threshold differential pressure is detected and/or after a threshold time period occurs, for example as detected by a system controller  925 , the filtration process can be halted. 
     Once the filtration process is halted, the self-cleaning cycle can be initiated. The self-cleaning cycle can begin by draining the liquid from the vessel  1100 .  FIG. 11C  illustrates the emptying of the liquid from the vessel  1100  after filtration is complete. The liquid remaining in the vessel  1100  can be directed back into a feed tank through the feed inlet  904  (see arrow  903 ). A purging gas may flow into the vessel  1100  via the inlet  924  to assist with clearing any remaining fluid within the vessel  1100 . As the gas flows into the vessel  1100 , the remaining liquid can flow back into a feed tank through inlet  904 . A drain tube  907  can be used to allow the fluid to be drained down to the top of the valve  906  using pressure within the vessel  1100  and or suction from the inlet  904 . Once empty, an inlet valve coupled to the inlet  904  can be closed. 
     The vessel can then contain the filter cake  1000  on the filter media.  FIG. 11D  illustrates the filter cake  1000  being dried with a drying gas that is passed into the vessel  1100  via the inlet  924 . The drying gas is utilized to dry the filter cake  1000  on the filter media  108 . The drying gas may enter the chamber  106  via the perforations  104  and may exit the filter  1100  via the outlet  902 .  FIG. 11E  illustrates the dried filter cake  1000  on the filter media  108 . As shown, the filter cake can start to crack based on shrinkage as the filter cake dries. 
     Once dried, the filter cake can be removed from the filter media via one or more back-pulses of gas.  FIG. 11F  illustrates a flow of gas entering the vessel  1100  via the outlet  902  depicted by the arrows  1004 . This back pulse flow of gas can cause the filter media to expand and dislodge the filter cake  1000  from the filter media  108  after the drying of filter cake  1000 . The dried filter cake can then break off and pass through the valve  906  for collection and disposal. After this back pulse flow of gas, the filtration and cleaning process is complete. Vessel  1100  may be ready for a subsequent filtration cycle for another batch of contaminated liquid. 
     The filter system and the filtering vessel(s) as described herein can be used for any type of process used to filter solids from liquids. As an example of a process that can use the filtering vessel in addition to chemical additions, a galvanizing process can be carried out and the filtering system can be used to precipitate iron and filter the precipitated iron from the flux solution. Galvanizing refers to the process of coating iron or steal with a protective layer of zinc. Prior to the zinc coating process, the iron or steel to be coated can be cleaned using various solutions to remove surface oxidation in order to provide for a suitable bond between the zinc and the iron or steel. 
     While a number of surface cleaning processes can be used, in some embodiments a flux solution can be used to clean the surface oxidation from the iron or steel. Various flux compositions can be used such as a zinc-ammonium chloride solution. When contacted with steel or iron, the flux solution can remove the oxidation layer, and some amount of iron can be solvated into the solution in the form of Fe 2+  and some particles can also be formed in the solution. In order to filter the flux solution, the flux solution can be passed through the filter system including any of the systems described herein. 
     In order to prevent a buildup of iron in the system, an oxidizer and pH control agent can be added into the flux solution prior to the flux solution passing into the filtering vessel. The oxidizer can convert the Fe 2+  to Fe 3+  and create insoluble precipitates in the solution. The pH control agent can serve to correct the pH of the flux solution as part of the oxidation reaction. Suitable oxidizers can include hydrogen peroxide, though other oxidizers such as chlorine dioxide, ozone, or potassium permanganate can also be used in some aspects. Suitable pH control agents can include any suitable acid or base that is compatible with the other components of the flux solution. 
     The flux cleaning process can be described with respect to the system of  FIG. 9 . In an embodiment, the process  952  can be a flux cleaning process that can use a flux solution that can pass to a feed tank  954 . The flux process  952  can comprise contacting a metal with a flux solution. Within the process  952 , the flux solution can entrain particles and dissolved iron to create the rich flux solution. 
     The rich flux solution can pass to a feed tank  954 . Within the feed tank  954 , one or more oxidizers and pH control agents can be dosed into the feed tank  954  to mix with the rich flux solution. An oxidation reaction can occur to convert the iron into a non-soluble species that can precipitate from the rich flux solution. A mixer can be used within the feed tank  954  to keep the precipitated iron dispersed in the solution and prevent settling and building of the iron within the feed tank. 
     The rich flux solution carrying the precipitated iron species can then pass to the filtering vessel  900 . The filtering vessel  900  can comprise any of the filtering vessels and configurations described herein. Within the filtering vessel  900 , the rich flux solution can pass through a filter element that can remove any particles in the rich flux solution, including the precipitated iron species. The flux solution with the solids filtered out can then pass through the filter element and out of the filtering vessel  900  as a clean flux solution before passing back to the flux process  952 . This process can continue until the filter element triggers a threshold such as a pressure drop across the filter element to indicate that the filter element needs cleaning. 
     When the filter element within the filtering vessel  900  needs to be cleaned, a self-cleaning cycle can be initiated. During the self-cleaning cycle, the flux solution passing to the filtering vessel  900  may be stopped. As described in more detail here, the process fluids within the filtering assembly  900  can first be drained from the filtering vessel  900 . In some embodiments, the feed tank can be drained with the fluids passing back to the process  952 , and the feed tank  954  can eb used to store the fluids within the filtering vessel  900  during the cleaning cycle. 
     Once the fluids are removed from the filtering vessel  900 , a drying gas can be introduced into the filtering vessel to dry the filtered solids on the filter element, including any particles within the flux solution and the precipitated iron species. Once dried, a back-pressure pulse or flow of gas can be supplied from the gas source  956  to break the dried filter materials loose from the filter element and cause the dried materials to fall to a bottom of the filtering vessel  900 . A valve or flap in the lower portion of the filtering vessel  900  can then be actuated to allow the dried solids to pass out of the filtering vessel  900 , as described in more detail herein. 
     In some embodiments, the filter element can use a filtrate material used to form a filter cake on the filter element. The filtrate can be useful in filtering finer particles such as precipitated iron species. The filtrate material can comprise any suitable material that can form a filter cake that is then used to filter the particulates or components from the process fluid. The filtrate used with the flux cleaning process can include any of those described herein. 
     Once the filter cake has been removed and the filter element has been cleaned, the cleaning process can be resumed by introducing the fluid starting with the fluid in the feed tank. The filtering of the stored flux solution in the feed tank  954  can help to ensure that no unfiltered flux solution is passed back to the flux process  952 . When a filtrate is used, the filtrate can be introduced into the feed tank with the flux solution. The mixer can ensure that the filtrate is mixed in the flux solution. The flux solution with the filtrate can then be circulated between the feed tank  954  and the filtering vessel  900  to form the filter cake on the filter element. Once the filtrate is filtered out of the flux solution, the flux solution can then be introduced into the filter assembly  900  directly or through the feed tank  954  to continue the normal filtering process. The filtering and self-cleaning cycles can be continued and repeated in order to maintain a desired level of filtering of the process fluids, and the oxidizers and pH control agents can be introduced into the system upstream of the filtering assembly  900  in order to control the amount of dissolved iron in the flux solution. 
     Having described various systems and methods herein, some embodiments can include, but are not limited to: 
     In a first embodiment, a filter comprises: a tube comprising perforations, the tube configured to receive a flow of a liquid from a first direction or a flow of a gas from a second direction opposite to the first direction; a filter media positioned concentrically around the tube; and one or more spacers positioned between the tube and the filter media to create a space between the tube and the filter media; wherein a portion of the filter media is configured to flex inward into the space during the flow of the liquid into the filter, and flex outward from the space during the flow of the gas exiting the filter. 
     A second embodiment can include the filter of the first embodiment, further comprising: a reinforcement core positioned within the tube, wherein the reinforcement core at least partially extends along a length of the tube and includes portions to support the tube and prevent deformation of the tube. 
     A third embodiment can include the filter of the second embodiment, wherein the reinforcement core includes recesses configured to receive filtered fluid. 
     A fourth embodiment can include the filter of any one of the first to third embodiments, further comprising: a volume reducer positioned within the tube, wherein the volume reducer includes an internal chamber and extends at least partially along a length of the tube, wherein the internal chamber is configured to not receive filtered fluid. 
     A fifth embodiment can include the filter of the fourth embodiment, wherein a passage extends through the volume reducer, wherein the passage is configured to receive filtered fluid. 
     In a sixth embodiment, a filter comprises: a plurality of tubes, each tube comprising perforations and each tube configured to receive a flow of a liquid from a first direction or a flow of a gas from a second direction opposite to the first direction; and a filter media positioned concentrically around the plurality of tubes to form a space between adjacent tubes of the plurality of tubes and a portion of the filter media; wherein the portion of the filter media is configured to flex inward into the space during the flow of the liquid into the filter, and flex outward from the space during the flow of the gas exiting the filter. 
     A seventh embodiment can include the filter of the sixth embodiment, wherein one or more tubes of the plurality of tubes comprises a reinforcement core positioned within the tube, wherein the reinforcement core at least partially extends along a length of the tube and comprises portions configured to support the tube and prevent deformation of the tube. 
     An eighth embodiment can include the filter of the seventh embodiment, wherein the reinforcement core comprises recesses to receive filtered fluid. 
     A ninth embodiment can include the filter of any one of the sixth to eighth embodiments, further comprising: a volume reducer positioned between the plurality of tubes, wherein the volume reducer includes an internal chamber and extends along a length of the tubes, wherein the internal chamber is configured to not receive filtered fluid. 
     A tenth embodiment can include the filter of the ninth embodiment, wherein a passage extends through the volume reducer, wherein the passage is configured to receive filtered fluid. 
     An eleventh embodiment can include the filter of any one of the sixth to tenth embodiments, further comprising a passage extending at least partially along lengths of the tubes, wherein the passage is positioned between the tubes, wherein the passage is configured to receive filtered fluid. 
     In a twelfth embodiment, a method of filtering a fluid comprises: receiving a liquid in a vessel including a filter; receiving the liquid in the filter from a first direction, wherein the filter comprises: a tube including perforations; a filter media positioned concentrically around the tube; and one or more spacers positioned between the tube and the filter media, wherein a space is created between the tube and the filter media when the liquid is received from the first direction; flexing a portion of the filter media inward into the space upon receipt of the liquid; accumulating a filter cake on the filter media in response to receiving the liquid in the filter from the first direction; receiving a gas in the filter from a second direction opposite to the first direction; flexing the portion of the filter media outwards from the space upon receipt of the gas; and removing the filter cake from the filter media based on flexing the portion of the filter media outwards. 
     A thirteenth embodiment can include the method of the twelfth embodiment, further comprising: drying the filter cake with the gas. 
     A fourteenth embodiment can include the method of the thirteenth embodiment, wherein the filter further comprises: a reinforcement core positioned within the tube, wherein the reinforcement core at least partially extends along a length of the tube and includes portions to support the tube and prevent deformation of the tube. 
     A fifteenth embodiment can include the method of the fourteenth embodiment, wherein the reinforcement core includes recesses to receive filtered fluid. 
     A sixteenth embodiment can include the method of any one of the thirteenth to fifteenth embodiments, wherein the filter further comprises: a volume reducer positioned within the tube, wherein the volume reducer includes an internal chamber and extends at least partially along a length of the tube, wherein the internal chamber does not receive filtered fluid. 
     In a seventeenth embodiment, a method comprises: receiving a liquid in a vessel including a filter; receiving the liquid in the filter from a first direction, wherein the filter comprises: a plurality of tubes, each tube comprising perforations; and a filter media positioned concentrically around the tubes to form a space between two tubes and a portion of the filter media; flexing the portion of the filter media inward into the space upon receipt of the liquid; accumulating a filter cake with the filter media; receiving a gas in the filter from a second direction opposite to the first direction; flexing the portion of the filter media outwards from the space upon receipt of the gas; and removing at least a portion of the filter cake from the filter media in response to flexing the portion of the filter media outwards. 
     An eighteenth embodiment can include the method of the seventeenth embodiment, further comprising: drying the filter cake with the gas. 
     A nineteenth embodiment can include the method of the eighteenth embodiment, wherein the filter further comprises: a reinforcement core positioned within each tube, wherein the reinforcement core at least partially extends along a length of each tube and includes portions to support each tube and prevent deformation of each tube. 
     A twentieth embodiment can include the method of any one of the seventeenth to nineteenth embodiments, wherein the filter further comprises: a volume reducer positioned within each tube, wherein the volume reducer includes an internal chamber and extends at least partially along a length of each tube, wherein the internal chamber does not receive filtered fluid. 
     A twenty first embodiment can include the method of any one of the seventeenth to twentieth embodiments, further comprising: a volume reducer positioned between the plurality of tubes, wherein the volume reducer includes an internal chamber and extends along a length of the tubes, wherein the internal chamber is configured to not receive filtered fluid. 
     A twenty second embodiment can include the method of the twenty first embodiment, wherein a passage extends through the volume reducer, wherein the passage is configured to receive filtered fluid. 
     In a twenty third embodiment, a method of filtering a fluid comprises receiving a flux solution in a feed tank; introducing an oxidizer into the flux solution in the feed tank; forming a precipitate in the flux solution within the feed tank in response to introducing the oxidizer; passing the flux solution with the precipitate to a filtering vessel containing a filter comprising a filter media; receiving the flux solution with the precipitate in the filter from a first direction; flexing a portion of the filter media inward into the space based on receipt of the flux solution with the precipitate; accumulating a filter cake on the filter media in response to receiving the flux solution in the filter from the first direction; receiving a gas in the filter from a second direction opposite to the first direction; flexing the portion of the filter media outwards from the space upon receipt of the gas; and removing the filter cake from the filter media based on flexing the portion of the filter media outwards. 
     A twenty fourth embodiment can include the method of the twenty third embodiment, wherein the filter comprises: a tube including perforations; the filter media positioned concentrically around the tube; and one or more spacers positioned between the tube and the filter media, wherein a space is created between the tube and the filter media when the flux solution is received from the first direction; 
     A twenty fifth embodiment can include the method of the twenty third embodiment, wherein the filter comprises: a plurality of tubes, each tube comprising perforations; and the filter media, wherein the filter media is positioned concentrically around the tubes to form a space between two tubes and a portion of the filter media. 
     A twenty sixth embodiment can include the method of any one of the twenty third to twenty fifth embodiments, further comprising: drying the filter cake with the gas prior to flexing the portion of the filter media outwards. 
     A twenty seventh embodiment can include the method of any one of the twenty third to twenty sixth embodiments, wherein the filter further comprises: at least one tube, and a reinforcement core positioned within the at least one tube, wherein the reinforcement core at least partially extends along a length of the at least one tube and includes portions to support the at least one tube and prevent deformation of the at least one tube. 
     A twenty eighth embodiment can include the method of the twenty seventh embodiment, wherein the reinforcement core includes recesses to receive filtered fluid. 
     A twenty ninth embodiment can include the method of any one of the twenty third to twenty eighth embodiments, wherein the filter further comprises: at least one tube, and a volume reducer positioned within the at least one tube, wherein the volume reducer includes an internal chamber and extends at least partially along a length of the at least one tube, wherein the internal chamber does not receive filtered fluid. 
     A thirtieth embodiment can include the method of any one of the twenty third to twenty ninth embodiments, further comprising: introducing a filtrate into the flux solution within the feed tank after removing the filter cake from the filter media; passing the flux solution with the filtrate through the filter media; forming a second filter cake on the filter media based on passing the flux solution with the filtrate through the filter media; and reintroducing the flux solution with the precipitate to the filtering vessel after forming the second filter cake. 
     The particular embodiments disclosed above are illustrative only, as the embodiments may be modified and practiced in different manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope of the present disclosure.