Patent Description:
Aspects and embodiments disclosed herein are directed generally to wastewater treatment systems which utilize settling basins and to apparatus and methods for operating settling basins.

Chain and scraper sludge collector equipment is designed to remove settled suspended solids (sludge) from rectangular settling basins, for example, rectangular concrete settling basins, in municipal and industrial water and wastewater treatment plants. In some implementations, rectangular settling basins may be from about <NUM> feet (<NUM> meters) to about <NUM> feet (<NUM> meters) wide, from about <NUM> feet (<NUM> meters) to about <NUM> feet (<NUM> meters) long, and from about eight feet (<NUM> meters) to about <NUM> feet (<NUM> meters) deep. Scraper flights are often used to scrape settled material on the basin floor to a sludge withdrawal location, for example, a hopper in the settling basin. Concurrently with the removal of sludge from the basin floor, other scraper flights may be utilized to push floating material, referred to generally as "scum," from the surface of liquid in the settling basin to a scum collector for removal.

The sludge and scum removal mechanism in a settling basin often includes two endless strands of chain that run the length of the settling basin. Scraper flights that span the width of the settling basin are mounted to the chain. The chain and the flights attached to the chain move through the settling basin to direct the sludge to the sludge withdrawal location in the floor at one end of the basin. The chain and flights are propelled by sprockets that are affixed to a headshaft that spans the width of the settling basin.

<CIT>relates to an integrated roof chain for the sludge collector of a water treatment facility.

In accordance with an aspect of the present disclosure there is provided a settling basin of a wastewater treatment system. The settling basin comprises a collector chain for driving a plurality of flights through the settling basin. The collector chain includes chain links comprising a plurality of side bars including an inner pair of side bars and an outer pair of side bars. Each of the plurality of side bars may be shaped as flattened open loops. The collector chain further includes stepped connecting pins configured to join the plurality of side bars. Each stepped connecting pin includes a first end including a head portion having a cross-sectional area larger than apertures defined by interior curved surfaces of end sections of the side bars through which the stepped connecting pin extends and a second end on an opposite end of the stepped connecting pin from the first end and having a cross-sectional area less than the cross-sectional area of the head portion. The collector chain further includes end caps configured to receive the second ends of the stepped connecting pins. Apertures configured to receive a retaining element are defined in the end caps and second ends of the stepped connecting pins.

In some embodiments, the end caps include internal bores configured to receive and retain the second ends of the stepped connecting pins.

In some embodiments, the end caps include reduced cross-sectional area portions and larger cross-sectional area portions having cross-sectional areas greater than cross-sectional areas of the reduced cross-sectional area portions. The end caps may further comprise grooves defined in the larger cross-sectional area portions of the end caps. The grooves may be configured to receive and retain ends of the retaining elements passing through the end caps. Each stepped connecting pins may further comprise a stepped portion having a cross-sectional area intermediate of the cross-sectional area of the head portion and the cross-sectional area of the non-stepped portion. The stepped portion may be configured to be disposed within the apertures of the plurality of side bars.

In some embodiments, each of the plurality of side bars includes inwardly extending projections that extend the interior curved surfaces of the end sections of the plurality of side bars beyond <NUM>°. At least one of the stepped connecting pins and end caps may include one or more projections configured to engage the inwardly extending projections of the plurality of side bars and suppress relative motion between the stepped connecting pins, end caps, and outer pairs of side bars.

According to claim <NUM>, the settling basin further comprises shields sized and shaped to align with sides of the plurality of side bars. The shields may be formed integral with one of the stepped connecting pins and end caps. The shields may comprise sheets that are retained on outer walls of the plurality of side bars. The shields may include apertures having recesses sized and shaped to receive radially extending projections disposed on one of the stepped connecting pins and end caps.

In some embodiments, at least one of the plurality of side bars includes a strain gauge. The at least one of the plurality of side bars may include a wireless transmitter configured to transmit data from the strain gauge to an external data recorder. The at least one of the plurality of side bars may further includes a memory configured to retain information related to time in service of the at least one of the plurality of side bars. The wireless transmitter may be configured to transmit the data related to time in service of the at least one of the plurality of side bars to the external data recorder. The external data recorder may be programmed to issue an alarm responsive the data related to time in service of the at least one of the plurality of side bars being indicative of the at least one of the plurality of side bars approaching or exceeding a rated useful life. The strain gauge and wireless transmitter may be potted with a water impermeable material at least one of on a surface of the at least one of the plurality of side bars or within a cavity defined in the at least one of the plurality of side bars. The external data recorder may be programmed to issue an alarm responsive to stress measured by the strain gauge exceeding a predefined level. The strain gauge and wireless transmitter may be disposed in a portion of a center section of the at least one of the plurality of side bars that is thinned relative to other portions of the center section. The at least one of the plurality of side bars may be formed of a different material than others of the plurality of side bars. The strain gauge may include one of an optical strain gauge and an acoustic strain gauge.

In some embodiments, the settling basin further comprises at least one sprocket including one of a strain gauge or pressure transducer configured to measure stress applied to the collector chain.

In some embodiments, at least one of the stepped connecting pins includes an internal core having a strain gauge configured to measure stress applied to the collector chain.

In accordance with another aspect, there is provided a collector chain for driving a plurality of flights through a settling basin of a wastewater treatment system. The collector chain includes chain links comprising a plurality of side bars including an inner pair of side bars and an outer pair of side bars. Each of the plurality of side bars may be shaped as flattened open loops. The collector chain further includes stepped connecting pins configured to join the plurality of side bars. Each stepped connection pins includes a first end including a head portion having a diameter larger than portions of the plurality of side bars through which the stepped connecting pin extends and a second end on an opposite end of the stepped connecting pins from the first end and having a diameter less than the diameter of the head portion. The collector chain includes end caps configured to receive the second ends of the stepped connecting pins and a strain gauge included in at least one of the plurality of side bars.

In accordance with an example, there is provided a method of operating a settling basin of a wastewater treatment system. The method comprises monitoring stress applied to a collector chain of the settling basin utilizing one of a strain gauge coupled to a chain link of the collector chain and a pressure transducer disposed in a sprocket of a chain drive system of the settling basin, and performing preventative maintenance on the settling basin responsive to the stress applied to the collector chain exceeding a predetermined value.

The method may further comprise receiving a wireless signal from the collector chain providing an indication of a time in service of the collector chain, and replacing at least a portion of the collector chain responsive to the indication of the time in service indicating that the at least a portion of the collector chain has reached or exceeded a rated useful lifetime.

Aspects and embodiments disclosed herein are not limited to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. Aspects and embodiments disclosed herein are capable of other embodiments and of being practiced or of being carried out in various ways.

Collector chains utilized in settling basins of wastewaters treatment plants may be subjected to harsh conditions. The liquid in a settling basin may exhibit swings in pH and/or changes in temperature from day to night or from season to season. Collector chains are also subject to mechanical stresses and repetitive vibrational stress associated with being driven through the settling basin.

Collector chains for use in settling basins of wastewater treatment plants desirably exhibit a number of properties. The collector chains are advantageously lightweight to facilitate installation or replacement and to minimize power utilized to drive the collector chains and attached flights through the settling basins. A collector chain should be mechanically strong along its entire length to resist deformation due to stress associated with being driven through the settling basin. A collector chain is desirably corrosion resistant so that it is not affected by the environment in the settling basin nor does it affect the environment due to its presence there. A collector chain should have few parts to facilitate installation or replacement and to reduce a number of possible failure points. A collector chain should also be resistant to accumulation of debris, for example, fibrous matter or rags in a settling basin. Accumulation of such debris in the collector chain may increase drag on the chain as it is driven through the settling basin, thus increasing the power used to drive the chain though the settling basin. Accumulation of such debris in the collector chain may also interfere with the passage of the collector chain over sprockets in the settling basin, potentially increasing power consumption, stoppage of the collector chain, or damage to the collector chain or sprockets. Collector chains may desirably provide an indication of stress experienced by links of the collector chain as the collector chain is drawn through a settling basin to provide advance notice of potential problems and provide for preventative maintenance to be performed rather than repair upon failure of a component of the settling basin.

One possible material from which a collector chain may be formed is metal. Settling basin collector chains have typically been fabricated out of carbon steel or stainless steel. The weight of the metal collector chains, however, is often substantial, and a large amount of power may be utilized to drive metal collector chains through a settling basin. The weight of the metal collector chains often requires the use of strong and heavy sprockets and associated mounting equipment, which may result in a settling basin having a high capital cost. The weight of the metal collector chains often makes maintenance difficult when the metal collector chains are to be removed and/or replaced. When carbon steel is used, corrosion can be a problem since the metal collector chains are normally not painted or otherwise treated for corrosion protection. If a corrosion resistant metal collector chain is desired, the collector chain may be constructed from stainless steel. The use of stainless steel, however, is costly due to the expense of the material and the difficulty of machining stainless steel as compared to carbon steel.

Another material from which a collector chain may be formed is engineering plastic (hereinafter, referred to as "plastic"). Plastics are typically corrosion resistant and generally lighter than most metals. Further, plastic collector chains can be either machined or molded, which reduces the cost of construction as compared to conventional steel collector chains. Most plastics, however, do not possess the mechanical strength desirable in a settling basin collector chain. A plastic collector chain may deform over time due to forces associated with driving the collector chain and flights through a settling basin.

Collector chains may be formed of ceramic materials. Ceramics are typically corrosion resistant and strong. Ceramics, however, typically have poor impact resistance and may shatter when experiencing a sharp force or crack after being subjected to repetitive vibrational stress.

Composite materials, for example, fiber reinforced plastics or metals embedded with ceramic materials may be strong, impact resistant, corrosion resistant, and lightweight. Many composite materials may be molded, which reduces the cost of construction as compared to conventional steel collector chains which may require machining. One drawback of many composite collector chains, however, is their cost relative to collector chains formed of common metals, for example, carbon steel or many plastics. Some forms of composite, however, are not excessively expensive and may provide an acceptable tradeoff between cost and mechanical properties desirable in a collector chain that may be superior to those of pure metal, plastic, or ceramic materials.

Aspects and embodiments disclosed herein involve utilizing a collector chain formed of a composite material (a "composite collector chain") in designs of chain and scraper sludge collector equipment in wastewater treatment plant settling basins instead of a conventional solid steel collector chain. The composite material may be a polymer matrix composite, for example, a nylon or epoxy matrix composite, a metal matrix composite, for example an aluminum or steel matrix composite, or a ceramic matrix composite, for example, a glass or alumina matrix composite. The composite material may include fibers, for example, glass, metal, carbon, aramid, or boron fibers embedded in the matrix. The composite material may include particles, for example, metal, polymer, or ceramic particles embedded in the matrix. In some embodiments, the composite is filament wound fiberglass reinforced plastic (FRP).

Aspects and embodiments disclosed herein may include a chain-drive assembly for use in a settling basin at least partially filled with wastewater. A chain-drive assembly disposed in the settling basin may include a parallel composite collector chains carrying flights and extending along both the bottom of the settling basin to remove settled sludge and at the surface of wastewater in the settling basin to collect and remove surface scum. The collector chains may include features to reduce the potential for the accumulation of debris in or in the links of the collector chains as compared to prior designs. The collector chains may include features to provide an indication of stress applied to links of the collector chains as they travel through the settling basin.

Other portions of the chain and scraper sludge collector equipment, for example, the headshaft, the flights, the bull sprocket, collector headshaft sprockets, idler sprockets, sprocket key elements, and/or wall bearings or stub posts may be formed of metal, for example, steel. In other embodiments any one or more of these portions of the chain and scraper sludge collector equipment may be formed of a polymer or a composite material, similar to that from which one or more portions of the collector chain may be formed.

Illustrated in <FIG> is a rectangular settling basin <NUM> which may be utilized in a wastewater treatment plant for the settling and removal of suspended solids from wastewater undergoing treatment. The settling basin <NUM> includes an opposed pair of sidewalls <NUM>, <NUM>, a pair of end walls <NUM>, <NUM>, and a bottom surface <NUM>. A pair of parallel collector chains <NUM> are driven by a headshaft <NUM>. The collector chains <NUM> engage the headshaft through collector headshaft sprockets <NUM> secured to the headshaft <NUM> proximate opposite ends of headshaft <NUM>. The collector chains <NUM> may also engage idler sprockets <NUM> which may rotate freely in wall bearings or about stub posts <NUM> secured to the sidewalls <NUM>, <NUM> of the settling basin <NUM>.

A motor, for example, an electric motor <NUM> external to the settling basin <NUM> drives a drive chain <NUM> which engages a bull sprocket <NUM> secured to the headshaft <NUM> proximate an end thereof to rotate the headshaft <NUM>. The headshaft <NUM> is supported by and rotates about headshaft mounts, for example, stub posts <NUM> secured to the sidewalls <NUM>, <NUM> of the settling basin <NUM>.

A series of sludge and scum collector flights <NUM> are connected at opposite ends to the collector chains <NUM>. In operation, the flights <NUM> collect sludge from the bottom surface <NUM> of the settling basin <NUM> and direct it into sludge hoppers <NUM> for removal. The flights <NUM> also skim the top surface of liquid in the settling basin and direct floating scum into a scum collector, for example, a scum pipe assembly <NUM>.

The settling basin <NUM> is illustrated in cross section along line <NUM>-<NUM> of <FIG> in <FIG>. The collector chain <NUM>, as illustrated in <FIG>, travels in a clockwise direction about the collector headshaft sprocket <NUM> and idler sprockets <NUM>. The flights <NUM> both scrape settled sludge (not shown) from the bottom surface <NUM> of the settling basin <NUM> into the sludge hopper <NUM> and skim scum (not shown) from the surface <NUM> of liquid in the settling basin <NUM> and direct it to the scum pipe assembly <NUM>.

The settling basin <NUM> is illustrated in cross section along line <NUM>-<NUM> of <FIG> in <FIG>. In <FIG> the drive chain <NUM> can be seen engaging the bull sprocket <NUM> secured to the headshaft <NUM>. In the embodiment illustrated in <FIG>, the bull sprocket <NUM> is configured with an external tooth section 155a which engages the drive chain <NUM> that is horizontally displaced toward a wall of the settling basin <NUM> from a base portion 155b where it is connected to the headshaft <NUM>.

An example of a collector chain <NUM> that may be utilized in the settling basin <NUM> is described in <CIT> (the '<NUM> patent).

An illustration of a chain link assembly of the example collector chain presented in the `<NUM> patent is reproduced <FIG> generally at <NUM>. The chain link assembly <NUM> includes two identical side bars <NUM> each having the shape of a flattened open loop with a pair of straight and parallel center sections <NUM> integrally connected by curved end sections <NUM>. The side bars <NUM> are joined by a connecting pin <NUM> and are retained on the connecting pin <NUM> by cotter pins <NUM> extending through each end of the connecting pin <NUM>.

Each side bar <NUM> is formed of a hardened resin matrix of, for example, a thermosetting polyester or epoxy resin. The matrix material is reinforced by high tensile strength, continuous filaments, for example, glass, steel, carbon, or aramid filaments which have been wound in parallel paths around the loop.

The side bars <NUM> include integral, inwardly extending projections <NUM> of hardened resin which extend the interior curved surface <NUM> of the end sections <NUM> to a circular arc greater than <NUM>°. These projections <NUM> serve to locate and maintain the end of the pin <NUM> longitudinally and concentrically at the ends of the side bars <NUM>.

The connecting pin <NUM> consists of a cylindrical core <NUM> having a polymeric sleeve <NUM> and a pair of drilled holes <NUM> at its ends for receiving cotter pins <NUM>. The core <NUM> is preferably a composite of a hardened thermoset resin reinforced by high strength filamentary material extending in the direction of the longitudinal axis of the core. The pin <NUM> also includes a sleeve <NUM> comprised of a low friction plastic material, which surrounds the core <NUM> to form a wear resistant coating or sleeve around the core.

The sleeve <NUM> includes an integral central barrel portion <NUM> adapted to engage the sprocket teeth, the central barrel portion of the sleeve having a material thickness greater than the material thickness of the opposite ends <NUM> of the sleeve, and the opposite ends <NUM> of the central portion <NUM> of the sleeve define shoulders adapted to be engaged by the sides of an inner pair of side bars <NUM>, the shoulders <NUM> and barrel portion <NUM> maintaining the side bars <NUM> in spaced apart relation.

The `<NUM> patent discloses that embodiments of the disclosed collector chain of comparable size and similar geometry to prior art chains has been shown to have an ultimate strength of nearly <NUM>,<NUM> lbs. (<NUM>,<NUM>. ) and is expected to have a working rating of <NUM> lbs. force (<NUM>,<NUM> Newtons), which is greater than that of cast iron chains.

Various improvements may be made to the collector chain disclosed in the '<NUM> patent. It has been discovered that it may be possible to reduce the number of individual parts forming a collector chain as compared to that disclosed in the '<NUM> patent, which may have about <NUM> parts per foot (about <NUM> parts per meter) of chain. It has also been discovered that the exposed cotter pins and the open loops of the side bars of the collector chain disclosed in the `<NUM> patent may undesirably tend to snag or collect debris such as rags or other fibrous debris when traveling through a settling basin. This collected debris may stress the links of the collector chain as it moves through a settling basin and may eventually cause a chain link to fail. The repair costs associated with such failures are significant, sometimes about $<NUM>,<NUM> or more due to the need to drain and sanitize the settling basin prior to performing repairs.

One example of an improved chain link assembly for a settling basin collector chain is illustrated generally at <NUM> in perspective view in <FIG> and in an exploded view in <FIG>. The chain link assembly <NUM> includes side bars <NUM> having the shape of a flattened open loop with a pair of straight and parallel center sections <NUM> integrally connected by curved end sections <NUM>. The side bars <NUM> are joined by stepped connecting pins <NUM>. The stepped connecting pins <NUM> differ from the connecting pins <NUM> described in the '<NUM> patent in that retaining elements, for example, cotter pins <NUM> are utilized only on one side of the stepped connecting pins <NUM>. The stepped connecting pins <NUM> include stepped portions 220A, non-stepped portions 220B, and a head 220C. The heads 220C have a greater external diameter or cross-sectional area than the stepped portions 220A. The stepped portions 220A have a greater external diameter or cross-sectional area than the non-stepped portions 220B. The cotter pins <NUM> pass through apertures <NUM> defined in end caps <NUM> that connect to the non-stepped portions 220B of the stepped connecting pins <NUM> and through corresponding passageways <NUM> defined in the non-stepped portions 220B of the stepped connecting pins <NUM> proximate terminal ends thereof (<FIG>).

The non-stepped portions 220B of the stepped connecting pins <NUM> may be disposed within central bores <NUM> of reduced diameter or reduced cross-sectional area portions <NUM> of the end caps <NUM> or central bores <NUM> passing through an entirety of the end caps <NUM>. The reduced diameter or cross-sectional area portions <NUM> of the end caps <NUM> may have the same or substantially the same diameter or cross-sectional area as the non-stepped portions 220B of the stepped connecting pins <NUM>. In other embodiments, the end caps <NUM> may extend into recesses or bores defined in the non-stepped portions 220B of the stepped connecting pins <NUM>.

Lower portions <NUM> of the cotter pins <NUM> are bent into an arc-shaped configuration after the cotter pins <NUM> are inserted through the end caps <NUM> and stepped connecting pins <NUM>. The arc-shaped lower portions <NUM> of the cotter pins <NUM> fit into grooves <NUM> defined in the surface of a larger diameter or cross-sectional area portion <NUM> (larger in diameter or cross-sectional area than the reduced diameter or cross-sectional area portions <NUM>) of the end caps <NUM>. The lower portions <NUM> of the cotter pins <NUM> have a reduced tendency to snag on rags or other debris than standard cotter pins because by being disposed in the grooves <NUM> rather than protruding from a side of the end caps <NUM>, the grooves <NUM> prevent the ends of the cotter pins <NUM> from snagging debris in wastewater in the settling basin.

It should be appreciated that although the stepped connecting pins <NUM>, end caps <NUM>, and portions of each are illustrated as being cylindrical or having circular cross-sections, it should appreciated that one or more portions of either the connecting pins <NUM> or end caps <NUM> may have non-circular cross-sections, for example, triangular, square, pentagonal, hexagonal, or oval cross sections, or cross-sections having any other appropriate geometrical shape.

Each side bar <NUM> is formed of a hardened resin matrix of, for example, a thermosetting polyester or epoxy resin. The matrix material is reinforced by high tensile strength, continuous filaments, for example, glass, steel, carbon, or KEVLAR® para-aramid synthetic fibers which have been wound in parallel paths around the loops of the side bars <NUM>.

The stepped connecting pins <NUM> may include a core <NUM> formed of hardened resin matrix of, for example, a thermosetting polyester or epoxy resin reinforced by high tensile strength, continuous filaments, for example, glass, steel, carbon, or KEVLAR® para-aramid synthetic fibers. The core <NUM> of the stepped connecting pins <NUM> may be formed by a pultrusion process wherein reinforcing filaments coated with resin are pulled through a die, causing the reinforcing filaments to be aligned in mutually parallel relation and causing the filaments to be compressed together to form a densified core material.

The stepped connecting pins <NUM> may include a sleeve <NUM> surrounding the core <NUM>. The sleeve <NUM> may be formed of nylon or another self-lubricating polymeric material. In other embodiments, the sleeve <NUM> may be formed of non-corroding metallic materials such as 304SS, 316SS, Nitronic <NUM>, Duplex or Super-duplex stainless steels or a polymer coated metal. The sleeve <NUM> may optionally be reinforced with high tensile strength, continuous or short, discrete filaments, for example, glass, steel, carbon, or KEVLAR® para-aramid synthetic fibers.

The side bars <NUM> include integral, inwardly extending projections <NUM> of hardened resin which extend the interior curved surface <NUM> of the end sections <NUM> to a circular arc greater than <NUM>°. These projections <NUM> serve to locate and maintain the non-stepped portions 220B of the stepped connecting pins <NUM> and the end caps <NUM> longitudinally and concentrically at the ends of the side bars <NUM>. The heads of the stepped connecting pins <NUM> have a larger diameter or cross sectional area than that of the aperture defined by the interior curved surfaces <NUM> of the end sections <NUM> of the side bars <NUM> and so are prevented from passing through the end sections <NUM> of the side bars <NUM> without the need for cotter pins or other fasteners or retaining elements.

Both the stepped portions 220A of the stepped connecting pins <NUM> and the end caps <NUM> may include one or more, for example, two or four outwardly extending projections or tabs <NUM> that engage internal sides <NUM> of the inwardly extending projections <NUM> (see <FIG>) in the outside side bars <NUM> (the side bars <NUM> between which are sandwiched other side bars <NUM>) to prevent or suppress relative motion between the stepped connecting pins <NUM>, the end caps <NUM>, and the outside side bars <NUM>. In non-limiting examples, center lines of the tabs may be offset by about <NUM>° about the circumferences of the stepped portions 220A of the stepped connecting pins <NUM> or endcaps <NUM>. In other embodiments, the projections or tabs may engage corresponding recesses in the outside side bars <NUM> to prevent or suppress relative motion between the stepped connecting pins <NUM>, the end caps <NUM>, and the outside side bars <NUM>. The lack of relative motion between the stepped connecting pins <NUM>, the end caps <NUM>, and the outside side bars <NUM> prevents wear on the outer surfaces of the stepped connecting pins <NUM> and end caps <NUM>, and on the interior curved surfaces <NUM> of the outside side bars <NUM>. The inside side bars <NUM> that are sandwiched between the outer side bars <NUM> are free to rotate about the stepped connecting pins <NUM> and end caps <NUM> relative to the outer side bars <NUM> to allow the collector chain to curve around sprockets in a settling basin.

Rollers <NUM> may be provided about the stepped connecting pins <NUM> between the inner side bars <NUM>. The rollers <NUM> may be free to rotate about the surface of the connecting pins <NUM> between the inner side bars <NUM>. The rollers <NUM> may be formed of a hard, corrosion resistant material, for example, stainless steel to prevent or reduce wear on the connecting pins <NUM> due to contact with sprockets in a settling basin. In other embodiments, the rollers <NUM> may be formed of a low friction material, for example, nylon, fiber reinforced nylon, or KEVLAR® para-aramid synthetic fibers.

Embodiments of the improved chain link assembly may include <NUM> parts per foot (<NUM> parts per meter) for embodiments in which the side bars <NUM> have <NUM> inch (<NUM>) total lengths as compared to <NUM> parts per foot (about <NUM> parts per meter) of chain as in some prior known settling basin collector chain designs. In a non-limiting example of a settling basin collector chain <NUM>, the side bars <NUM> have <NUM> inch (<NUM>) total lengths with a <NUM> inch (<NUM>) center-to-center distance between adjacent stepped connecting pins <NUM> and heights of <NUM> inches (<NUM>). The stepped connecting pins <NUM> may have overall lengths of about <NUM> inches (<NUM>) with the stepped potions 220A having lengths of about <NUM> inches (<NUM>) and diameters of about <NUM> inches (<NUM>), the non-stepped portions 220B having lengths of about <NUM> inches (<NUM>), external diameters of about <NUM> inches (<NUM>) and internal diameters of about <NUM> inch (<NUM>), the head 220C having a length of about <NUM> inches (<NUM>) and a diameter of about <NUM> inches (<NUM>), and the tabs <NUM> having lengths of about <NUM> inches (<NUM>) and heights of about <NUM> inches (<NUM>). The end caps <NUM> may have overall lengths of about <NUM> inches (<NUM>) with the reduced diameter portions <NUM> having lengths of about <NUM> inches (<NUM>), outer diameters of about <NUM> inches (<NUM>), and inner diameters of about <NUM> inches (<NUM>) and the larger diameter portions <NUM> having lengths of about <NUM> inches (<NUM>) and diameters of about <NUM> inches (<NUM>).

In some embodiments, the settling basin collector chain <NUM> may include shield elements to help prevent debris from being caught within the open loops of the individual side bars <NUM>. The shield elements may be in the form of sheets of material. An example of settling basin collector chain <NUM> including shield elements is illustrated in perspective view in <FIG> and in an exploded view in <FIG>. As illustrated in <FIG> and <FIG> the shield elements may include or consist of covers <NUM> sized and shaped to align with sides of the side bars <NUM> and block the open space within the open loops of the individual side bars <NUM>. The covers <NUM> may be disposed on outer sidewalls of the individual side bars <NUM>. The covers <NUM> may be held in place on the outer side bars <NUM> on one side of the collector chain <NUM> between the heads 220C of the stepped connecting pins <NUM> and outer sidewalls <NUM> of the outer side bars <NUM> and on the outer side bars <NUM> on the other side of the collector chain <NUM> between the end caps <NUM> and outer sidewalls <NUM> of the outer side bars <NUM>. The covers <NUM> on the outside of the inner side bars <NUM> may be sandwiched between inner walls <NUM> of the outer side bars <NUM> and outer walls <NUM> of the inner side bars <NUM>.

The covers <NUM> may include apertures <NUM> to receive the stepped portions 220A of the stepped connecting pins <NUM> or the reduced diameter portions <NUM> of the end caps <NUM>. The apertures <NUM> of the covers <NUM> may include recesses <NUM> sized and shaped to receive the projections or tabs <NUM> of the stepped connecting pins <NUM> and end caps <NUM>.

The covers <NUM> may be formed of a polymeric material, for example, polytetrafluoroethylene (PTFE), nylon, or another suitable polymer.

In some embodiments, as illustrated in <FIG> and <FIG>, covers <NUM> are distinct or formed separately from other portions of the collector chain. In other embodiments, the covers <NUM> may be formed integral with one or more of the side bars <NUM>, stepped connecting pins <NUM>, or end caps <NUM>.

In some embodiments, the components of the settling basin collector chain <NUM> may be configured to provide a customer with a choice of whether or not to install covers <NUM> on faces of the side bars <NUM>. As illustrated in <FIG>, one or more components of the settling basin collector chain <NUM>, for example, the connecting pins <NUM> may be sized to provide gaps <NUM> between the heads 220C of the connecting pins <NUM> and the outer sidewalls <NUM> of the outer side bars <NUM> and/or between the inner walls <NUM> of the outer side bars <NUM> and outer walls <NUM> of the inner side bars <NUM>. The gaps <NUM> are sized to accommodate the covers <NUM> if one desires to include the covers in the settling basin collector chain <NUM>. The covers <NUM> may be between about <NUM> inches (<NUM>) and about <NUM>/<NUM> of an inch (<NUM>) thick, and the gaps may be similarly sized. If one were to choose not to include the covers <NUM> in a portion or all of the settling basin collector chain <NUM>, washers <NUM>, illustrated in <FIG>, may be inserted between the heads 220C of the connecting pins <NUM> and the outer sidewalls <NUM> of the outer side bars <NUM> and/or between the inner walls <NUM> of the outer side bars <NUM> and outer walls <NUM> of the inner side bars <NUM> to fill the space that would otherwise be present due to the gaps <NUM>.

A comparison between settling basin collector chains <NUM> with and without covers <NUM> are illustrated in partial cross-section in <FIG>.

In some embodiments, one or more components of a settling basin collector chain <NUM> or other components of a collector chain drive system for a settling basin may include one or more sensors to provide an indication of one or more conditions within the settling basin. The one or more conditions may include, for example, stress or strain on the collector chain <NUM> that may be indicative of an undesirable or unusual situation. The undesirable or unusual situation may be a different (greater or lesser) than expected stress or stain being applied to the collector chain <NUM> or to sprockets in the collector chain <NUM> drive and support system of the settling basin. An observation of a stress or strain applied to the collector chain <NUM> or to sprockets that is different than expected may be indicative of a different amount of sludge present in the settling basin than expected or may be indicative of interference with the collector chain <NUM> drive and support system due to, for example, debris being caught in the collector chain <NUM>. An indication of the undesirable or unusual situation may provide for an operator of the settling basin to investigate the settling basin for a potential cause of the undesirable or unusual situation and make adjustments or perform preemptive repairs or preventative maintenance to avoid failure of the collector chain <NUM>, collector chain drive system or sprockets, or other portion of the settling basin.

In one example, illustrated in <FIG>, a sensor/transmitter <NUM> may be installed in or mounted to a portion of one or more side bars <NUM> of a settling basin collector chain <NUM>. The sensor/transmitter <NUM> may be a strain gauge sensor including wireless data transmission capabilities and an internal battery. The sensor/transmitter <NUM> may be mounted on a sidewall <NUM> of the side bar <NUM> as illustrated in <FIG> or embedded in a cavity <NUM> defined in the side bar <NUM> as illustrated in <FIG>. A potting material <NUM> that is water impermeable and resistant or inert with respect to the liquid in the settling basin, for example, an epoxy or other suitable potting material may be disposed about the sensor/transmitter <NUM> to protect it from damage due to contact with the liquid in the settling basin. The sensor/transmitter <NUM> may be disposed in a portion <NUM> of the center section <NUM> of the side bar <NUM> that is thinned relative to other portions of the center section <NUM> but which is thick enough to carry the rated working load of the side bar <NUM>. The thinned portion <NUM> may deform under stress to a greater extent than the remainder of the center section <NUM> of the side bar <NUM> and thus provide for greater sensitivity of the sensor/transmitter <NUM> than if it were disposed on a non-thinned portion of the side bar. A corresponding thinned portion <NUM> having a thickness T may be defined on the opposite center section arm <NUM> of the side bar <NUM> so that the side bar <NUM> deforms evenly under applied stress and does not cause misalignment with adjacent side bars under applied stress.

The sensor/transmitter <NUM> may communicate via the Bluetooth wireless technology standard, Zigbee, Wi-Fi or any other desired standard or protocol to a monitor/data recorder <NUM> external to the settling basin. In some embodiments, the sensor/transmitter <NUM> may include one of the nBlue™ nano ampere network modules available from BlueRadios Inc. to provide wireless data transmission to the monitor/data recorder <NUM>. The sensor/transmitter <NUM> may transmit to the monitor/data recorder <NUM> continuously, or in other embodiments, on a periodic basis, for example, once every <NUM> minutes, once every <NUM> minutes, or at a different periodicity to preserve battery life. The sensor/transmitter <NUM> may include a memory, for example, RAM or flash memory to record a pattern of stress or strain over time to transmit to the monitor/data recorder <NUM> on a periodic basis and/or when the monitor/data recorder <NUM> requests data regarding the pattern of stress or strain over time or an instantaneous stress or strain measurement from the sensor/transmitter <NUM>.

The sensor/transmitter <NUM> may provide an indication of strain exerted on the side bar <NUM> to the monitor/data recorder <NUM> as it travels through the settling basin. Strain exerted on the side bar <NUM> may be observed to increase as the side bar <NUM> and associated flights, for example, flights <NUM> as illustrated in the settling basin <NUM> of <FIG> pass though sludge on the floor of the settling basin and may be observed to decrease as the side bar <NUM> and associated flights <NUM> exit the sludge bed and move toward the top of the basin or surface of fluid in the basin.

A pattern of stress (or strain) verses time and/or positon of the side bar <NUM> and associated flights <NUM> in the settling basin may be collected over time and a mathematical model or an expected pattern of stress (or strain) verses time and/or positon of the side bar <NUM> and associated flights <NUM> in the settling basin may be developed by the monitor/data recorder <NUM>. An observation by the monitor/data recorder <NUM> of stress in the side bar <NUM> exceeding a predefined level or of a deviation from the mathematical model or pattern by more than a desired amount may cause the monitor/data recorder <NUM> to issue an alarm to an operator of the settling basin <NUM>. A deviation resulting in the alarm may be, for example, a strain <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% or more different (greater or less) than expected for a particular time and/or position of the side bar <NUM> and associated flights <NUM> in the settling basin or a deviation that violates a set of statistical process control rules established for the mathematical model or pattern of expected strain (or stress). For example, a pattern of stress (or strain) versus time and/or positon of the side bar <NUM> and associated flights <NUM> in the settling basin under normal operating conditions may exhibit the pattern illustrated in <FIG> at <NUM>. If the observed pattern of stress changed to exhibit the pattern indicated at <NUM>, an alarm may be issued by the monitor/data recorder <NUM> that the sludge bed in the settling basin <NUM> may be thicker or deeper than expected. Spikes <NUM> in the stress pattern may be indicative of a link in the settling basin collector chain <NUM> carrying debris that interferes with the passage of the link over a sprocket of the settling basin. Observation of such spikes <NUM> may cause the monitor/data recorder <NUM> to issue an alarm that there may be an issue with one or more links of the settling basin collector chain <NUM>.

In other embodiments, the memory of the sensor/transmitter <NUM> may include information identifying the particular side bar <NUM> to which it is coupled. The sensor/transmitter <NUM> may transmit the identifying information along with any stress or strain data to the monitor/data recorder <NUM> so the monitor/data recorder <NUM> can determine from which side bar <NUM> the data transmission originated. Additionally or alternatively, the memory of the sensor/transmitter <NUM> may include information regarding a manufacturing date of the side bar <NUM> or when the side bar <NUM> or collector chain <NUM> including the side bar <NUM> was put into service. The side bar <NUM> or collector chain <NUM> may have a rated useful life. The sensor/transmitter <NUM> may transmit the data regarding the age or time in service of the side bar <NUM> and/or collector chain <NUM> to the monitor/data recorder <NUM> on a periodic basis or when such information is requested by the monitor/data recorder <NUM>. The monitor/data recorder <NUM> may issue an alert or alarm to an operator of the settling basin responsive to the data regarding the age or time in service of the side bar <NUM> and/or collector chain <NUM> being indicative of the side bar <NUM> and/or collector chain <NUM> nearing, reaching, or exceeding its rated useful life. The operator may thus be informed that the side bar <NUM> and/or collector chain <NUM> may need to be replaced and the operator may perform preventative maintenance to replace the side bar <NUM> and/or collector chain <NUM> prior to failure of same.

In some embodiments, the side bar <NUM> including the sensor/transmitter <NUM> may be placed in a link of a collector chain <NUM> in parallel with a side bar <NUM> that is substantially similarly or identically shaped and formed of the same material or materials so that both side bars <NUM> exhibit the same degree of strain in response to an applied stress to keep the collector chain <NUM> straight and the sides of the collector chain <NUM> aligned.

The side bar <NUM> including the sensor/transmitter <NUM> may be formed of the same or similar materials as the other side bars of the collector chain <NUM> (e.g., side bars <NUM> as described above). In other embodiments, however, the side bar <NUM> including the sensor/transmitter <NUM> may be formed of a different material or materials as the other side bars of the collector chain <NUM>. Different side bars formed of fiber reinforced polymer may exhibit different stress/strain behavior due to variability inherent in the manufacturing process. It may thus be desirable to form a side bar <NUM> including the sensor/transmitter <NUM> of a material that has less variability in stress/strain behavior from one side bar to another. Such a material may include, for example, stainless steel. One particular grade of stainless steel that may be utilized for the body of side bar <NUM> including the sensor/transmitter <NUM> may be <NUM>-<NUM> stainless steel.

The sensor/transmitter <NUM> included in the side bar <NUM> may be any of various commonly available electromechanical, semiconductor, or microelectromechanical system (MEMS) strain gauges. One non-limiting example of a strain gauge that may be used for the sensor/transmitter <NUM> is the T24-SA wireless strain gauge available from Metrolog. In other embodiments, the sensor/transmitter <NUM> may be an optical or acoustic strain gauge. As illustrated in <FIG> an embodiment of a side bar, indicated at <NUM> may include a strain sensor system <NUM> including an optical or acoustic (e.g., ultrasound) transmitter or transceiver <NUM> and an associated receiver or reflector <NUM>. The strain senor system <NUM> may also include a wireless transmitter <NUM> as described above with reference to the sensor/transmitter <NUM>. Strain induced in the side bar <NUM> will be reflected in a change of length of the side bar <NUM> which may cause a change in distance between the transmitter or transceiver <NUM> and associated receiver or reflector <NUM>. This change in distance may be recorded by the strain senor system <NUM> and transmitted to a monitor/data recorder such as monitor/data recorder <NUM> described above.

In other embodiments, the transmitter or transceiver <NUM> may emit an acoustic signal into the body of the side bar <NUM> itself. The time the acoustic signal takes to reach the receiver or reflector <NUM> or to return to the transmitter or transceiver <NUM> though the body <NUM> of the side bar <NUM> may be dependent on the strain placed on the side bar. Data regarding the time of travel of the acoustic signal may be provided to the monitor/data recorder <NUM> via the wireless transmitter <NUM> and the monitor/data recorder <NUM> may derive the stress applied to the side bar <NUM> from this data.

Embodiments of the sensor/transmitter <NUM> or strain senor system <NUM> may be included in multiple side bars <NUM>, <NUM> in a collector chain <NUM> of a settling basin <NUM> to provide simultaneous data from multiple areas with the settling basin <NUM>.

One or more sensors may also or alternatively be included in one or more portions of a collector chain drive system of a settling basin <NUM> other than a side bar <NUM>, <NUM>. As illustrated in <FIG> a strain gauge or pressure transducer, wireless transmitter, and battery, (and optionally, a memory element, for example, RAM or flash memory) collectively indicated at <NUM> may be included in one or more teeth <NUM> of at least one sprocket <NUM> of a collector chain drive system of a settling basin <NUM>. The sensor/transmitter <NUM> may be potted in a tooth <NUM> of a sprocket <NUM> in a similar manner as the sensor/transmitter <NUM> is potted in the side bar <NUM> as illustrated in <FIG> to protect the sensor/transmitter <NUM> from moisture or other contaminants.

The sprocket <NUM> may be a collector headshaft sprocket <NUM>, idler sprockets <NUM>, or a drive sprocket included in or coupled to the electric motor <NUM> in a settling basin <NUM> such as that described with reference to <FIG>.

The sensor/transmitter <NUM> may provide an indication of stress applied by the collector chain <NUM> or individual links thereof to the sprocket <NUM> and/or to each individual one of the teeth <NUM> including a sensor/transmitter <NUM>. The sensor/transmitter <NUM> or sensor/transmitters <NUM> may measure and provide an indication of stress exerted on the collector chain <NUM> as a whole to a monitor/data recorder <NUM> and/or may provide stress data for individual links of the collector chain <NUM> to the monitor/data recorder <NUM>. The sensor/transmitter <NUM> may also send information identifying the sprocket <NUM> and/or age or time in service of the sprocket <NUM> to the monitor/data recorder <NUM> in a similar manner as described above with reference to the sensor/transmitter <NUM> of the side bar <NUM>.

Communications between the sensor/transmitters <NUM> and the monitor/data recorder <NUM> may be performed similarly as described above with reference to the sensor/transmitter <NUM>.

The monitor/data recorder <NUM> may determine global conditions within the settling basin <NUM>, for example, an amount of sludge present in the settling basin <NUM> from data received from the sensor/transmitter <NUM> or sensor/transmitters <NUM>. The monitor/data recorder <NUM> may also or alternatively determine conditions specific to individual links or sections of the collector chain <NUM>, for example, whether a portion or link of the collector chain <NUM> may have debris caught in itself from data received from the sensor/transmitter <NUM> or sensor/transmitters <NUM>. The sprocket <NUM> may be formed of a material with a low degree in variation in stress/strain behavior from one unit to the next, for example, stainless steel.

In a further embodiment, a sensor/transmitter <NUM> as disclosed with reference to the sprocket <NUM> may be included in an embodiment of a connecting pin <NUM> of a collector chain <NUM> or in the core <NUM> of one or more connecting pins <NUM> of a collector chain <NUM> as illustrated in <FIG>. The sensor/transmitter <NUM> included in the core <NUM> of the one or more connecting pins <NUM> may provide similar data as described above with reference to the sensor/transmitter <NUM> of the side bar <NUM>. The core <NUM> may be formed of a material with a low degree in variation in stress/strain behavior from one unit to the next, for example, stainless steel.

In another aspect of the present disclosure, it is to be understood that an existing settling basin <NUM> may be retrofit to include any of the embodiments of the collector chain side bars or other portions of the collector chain drive system described herein.

Having thus described several aspects of at least one embodiment of this disclosure, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within scope of the disclosure as defined in the appended claims. For example, although aspects of the present disclosure are described as used to remove biological floc from wastewater, these aspects may be equally applicable to the removal of any form of suspended solids, for example, inorganic suspended solids or fats, oil, or grease in a settling unit or vessel. Aspects of the wastewater treatment systems described herein may also use non-biological treatment methods rather than biological treatment methods for the treatment of wastewater. Accordingly, the foregoing description and drawings are by way of example only.

Claim 1:
A settling basin (<NUM>) of a wastewater treatment system, the settling basin (<NUM>) comprising:
a collector chain (<NUM>) for driving a plurality of flights (<NUM>) through the settling basin (<NUM>), the collector chain (<NUM>) including chain links comprising:
a plurality of side bars (<NUM>) including an inner pair of side bars (<NUM>) and an outer pair of side bars (<NUM>), each of the plurality of side bars (<NUM>) shaped as flattened open loops;
stepped connecting pins (<NUM>) configured to join the plurality of side bars (<NUM>), each stepped connecting pin (<NUM>) including a first end including a head portion having a cross-sectional area larger than apertures (<NUM>) defined by interior curved surfaces of end sections of the side bars (<NUM>) through which the stepped connecting pin (<NUM>) extends and a second end on an opposite end of the stepped connecting pin (<NUM>) from the first end and having a cross-sectional area less than the cross-sectional area of the head portion;
end caps (<NUM>) configured to receive the second ends of the stepped connecting pins (<NUM>); and
apertures (<NUM>) defined in the end caps (<NUM>) and second ends of the stepped connecting pins (<NUM>) configured to receive a retaining element, characterised in that the chain further comprises shields sized and shaped to align with sides of the plurality of side bars (<NUM>).