Patent Publication Number: US-2020298149-A1

Title: Wastewater screen filter and chain tensioning system

Description:
This application is a Non-provisional Patent Application of U.S. Provisional Patent Application No. 62/822,788, entitled “WASTEWATER SCREEN FILTER AND CHAIN TENSIONING SYSTEM”, filed Mar. 22, 2019, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to the field of wastewater treatment, and more particularly to a screen filter for use in such applications that provides for a tensionable chain drive that may be used to remove debris with rakes within the screen filter. 
     In the field of wastewater treatment, a range of components are used at various stages of water capture and processing, ultimately resulting in treated water that may be used or released into the environment. One component that is often found at the initial stages of wastewater collection and treatment is the screen filter. These devices allow for water to flow into a screen which collects larger debris while allowing the strained water to flow through for further filtering and treatment. In one type of screen filter, one or more chain-mounted rakes are continuously moved over a screen field to remove the debris that is collected from the water. Typically, the one or more chains are moved by a drive assembly over sprockets, so that the collection and raking operations may be performed without operator intervention, at least during times when water is flowing through the filter. The debris is scraped from the rakes and may be disposed of accordingly. 
     Persistent problems in such devices may result from wear on the moving elements, particularly on the chain and on the sprocket assemblies used to guide the chain. Such wear may result in the loss of efficiency of the drive used to move the rakes, and may be costly. There is a need, therefore, for improved techniques for managing the wear and tear of the chain drive and related components. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below. 
     In one embodiment, screen filter for wastewater applications includes a chain tensioning system. The chain tensioning system provides a tensioning force for a screen filter chain. The chain tensioning system includes a chain adjuster device configured to tension the screen filter chain. The chain tensioning system additionally includes a sensor configured to provide a signal representative of a load applied by the chain adjuster; wherein the chain adjuster device is configured to apply a force in a direction that tensions the chain and wherein the signal provided by the sensor is representative of the force. 
     In a second embodiment, method for making a screen filter for wastewater applications is provided. The method includes providing a chain adjuster device configured to tension the screen filter chain. The method further includes providing a sensor configured to provide a signal representative of a load applied by the chain adjuster; wherein the chain adjuster device is configured to apply a force in a direction that tensions the chain and wherein the signal provided by the sensor is representative of the force. 
     In a third embodiment, a non-transitory computer readable medium comprises instructions that when executed cause a processor to actuate a chain adjuster device. The instructions further cause the processor to receive a signal from a sensor configured to provide the signal representative of a load applied by the chain adjuster device and to stop actuating the chain adjuster device when a desired chain tension is derived. 
     The present invention provides for a novel chain tensioning system disposed in a screen filter. The invention offers an improved tensioning control for the chain, such that a tensioning force is applied more evenly, thus minimizing or eliminating mechanical stress between components, including components disposed at opposing ends of the chain. In one embodiment, the chain tensioning system may include one or more sensors, such as load cells. As the chain becomes more “loose” due to wear, a tensioning force may be adjusted to compensate for any slack by monitoring the load cells. In one example, a chain adjuster device, such as a jack, may be monitored in use via the load cell(s). As a desired loading is reached, the actuation of the jack may be stopped, and the chain and related systems secured to the desired loading. By providing for an improved chain tension, the efficiency of the chain drive may be improved, and component wear may be minimized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a perspective view of an embodiment of screen filter for wastewater applications employing a chain tensioning system; 
         FIG. 2  is a side view of an embodiment of the screen filter for wastewater applications of  FIG. 1 , showing details of a chain tensioning system; 
         FIG. 3  is a more detailed section view of an embodiment the chain tensioning system of  FIG. 2 , including a chain adjuster device; 
         FIG. 4  is a more detailed view of an embodiment the chain tensioning system of  FIG. 3 , including various components of the chain tensioning system, including a load cell; 
         FIG. 5  is a detailed view of embodiments certain components of the chain tensioning system where the load cell is disposed on a different location; 
         FIG. 6  is block view of an embodiment of a control system suitable for controlling the chain tensioning system; 
         FIG. 7  is flowchart of an embodiment of a process suitable for using the chain tensioning system; 
         FIG. 8  is a side view illustrating an embodiment of the screen filter that includes a chain adjuster device; 
         FIG. 9  is a front view illustrating two of the chain adjuster devices of  FIG. 8  disposed on opposite sides of the screen filter, and; 
         FIG. 10  is a side sectional view of and embodiment of the chain adjuster device of  FIG. 8  illustrating further details. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of an embodiment of a screen filter  10  that would be used in a wastewater treatment facility. As will be appreciated by those skilled in the art, the screen filter may be positioned vertically or at an angle at an entrance side of a collection point or treatment facility. An open end  12  of the screen filter  10  receives a flow of water as indicated by arrow  14  through a filter screen  16  which may be seen in the interior volume  18  in the image of  FIG. 1 . The filter screen  16  may stop large debris from flowing through the filter  10  to downstream components, while allowing water to flow through for subsequent filtering and treatment. 
     Also depicted is a chain drive assembly  20  including a motor, such as an electric motor  22  used to drive one or more chains  24  (depicted as a broken line). The chains  24  may use sprockets, such as a sprocket  26 , to move a rake useful in removing debris that may collect on the filter screen  16 . The debris may be collected and disposed of appropriately, as depicted by arrows  23 . Unfortunately, wear on the chain  24  or improper chain  24  tensioning may result in certain “slackness,” thus reducing overall efficiency of the chain drive assembly  20  and increasing wear on components of the screen filter  10 . Advantageously, the chain  24  is mounted on a drive side wall  28  having a drive side chain tensioning system shown in more detail in the figures below. Likewise, a chain  24  is mounted on an opposite side wall  30  having a wall side chain tensioning system shown in more detail in the figures below. The chain tensioning systems may enable a more efficient tensioning of the chain  24 , thus improving chain drive  20  efficiency and minimizing wear and tear on components of the screen filter  10 . 
       FIG. 2  is a side view of an embodiment of the screen filter  10  of  FIG. 1 . More specifically, the figure depicts the side wall  30  having the drive assembly  20  with the electric motor  22 . A debris plate  32  is disposed near a bottom downstream side of the filter screen  16  (shown in  FIG. 1 ) and serves to collect the debris that may be present in the wastewater that flows through the filter. Above the debris plate  32 , one or more plate sections may be provided for allowing the debris to be raised on the chain  24  and rakes  34  positioned along the chain. Depending upon the design of the screen filter, and its length, one or many such rakes  24  may be provided along the length of the chain. These rakes  24  are raised on the downstream side of the interior volume of the screen filter and lowered along the upstream side. The rakes  24  progressively advance over the debris plate  32  and remove any debris that has collected there, raising it to an upper end of the screen filter  10 . A scraper assembly may contact the rakes  24  at on a debris chute  36  end of the screen filter  10  and pushes the debris into the debris chute  36  as shown by the arrows  23 . 
     As shown in  FIG. 2 , the chain  24  is wound around sprockets  26  and is guided by the sprockets at lower and upper ends of the screen filter  10 . In most applications, two such chains  24  will be provided, one on either side of the assembly. The chains  24 , then, span these two sprockets  26  and over a length of the screen filter  10 . The chains  24  are driven by a gear reducer  38  at the upper end of the screen filter, which is itself driven by the electric motor  22 . This mechanism may run continuously, or at least during periods when wastewater is being received to continuously remove debris from the water and maintain the screen filter in an unobstructed operative condition. In the depicted embodiment, a chain tensioning system  40  includes a chain adjuster device  42  (e.g., adjusting jack) and may be used to maintain a more suitable chain  24  tension. Indeed, should the chain  24  experience slack, the chain tensioning system  40  may be actuated to “take up” the slack and provide for uniform chain tension. A similar chain tensioning system  40  may be disposed on the opposite chain drive side wall  28 . Accordingly, the chain tensioners may improve efficiency of the chain drive  20  and reduce wear of components of the screen filter  10 . 
       FIG. 3  is a section A-A view of an embodiment of a top portion of the screen filter  10  illustrating further details of the chain tensioning systems  40 , including the chain adjuster device  42 . In use, the chain  24  “stretch” over time. Accordingly, the chain tensioning systems  40  may be used to tension the chain  24  by moving the chain  24  and connected systems, e.g., systems  20 , motor  22 , in an upwards direction  44 . More specifically, the adjuster device  42  is actuated so that a component of the adjuster device  42  abuts against a lower assembly portion  46  of the systems  20 . 
     The techniques described herein provide for using one or more load cells to monitor a load as the adjuster device  42  applies a force to the lower assembly portion  46 . As the load increases, the chain&#39;s slack may be removed, until a more optimal tension for the chain  24  is reached. In some embodiments, once the desired tension, as measured by the load, is achieved, the adjuster device  42  may be reset so that it no longer abuts the lower assembly portion  46  and the chain  24  may be kept in place (e.g., prevented from moving down) by refastening certain fasteners, such as bolt and nuts, screws, latches, and so on. 
       FIG. 4  is a side view illustrates embodiments of certain of the components of the chain tensioning system  40  in more detail, including the chain adjuster device  42 . In the depicted embodiments, the chain adjuster device  42  may be manually actuated and/or actuated via a controller, e.g., via a piston assembly  50 , to raise a piston or ram  52  so that the ram  52  abuts against a take up spacer  54  disposed in a pocket  56  of the lower assembly portion  46 . 
     As part of the chain tensioning systems  40 , a load cell seat assembly  58  may include a load cell  60 . The load cell seat assembly  58  may be removable. That is, before starting the chain  24  tensioning process, the load cell seat assembly  58  may be disposed onto the ram  52 . For example, the user may place the load cell seat assembly  58  onto the ram  52 , and subsequently actuate the chain adjuster device  42 , e.g., via the piston assembly  50 . As the ram  52  moves in the upward direction  44 , the load cell  60  may abut against the take up spacer  54 . As more force is applied by the ram  52 , the load cell  60  may register increasing load measurements. The operator may continue actuating the chain adjuster device  42  until a desired load reading incoming from the load cell  60  is achieved. In some embodiments, the load cell  60  may be communicatively coupled, via wired or wireless techniques (e.g., Bluetooth, Wi-Fi, mesh networks) to a load meter that may then provide the load readings or load graph. The load meter may include an application on a tablet, laptop, smart phone, smart watch, and the like, and/or a dedicated meter having a built-in display suitable for presenting the load readings and/or loading graph. It is to be noted that in some embodiments the load cell  60  may be permanently placed as part of the lower assembly portion  46 . Multiple load cells  60  may also be used, and techniques such as an average and/or median may be used to determine when the desired load has been achieved. 
     In another embodiment, the load cell  60  may be disposed on a base of the chain adjuster device  42 , as shown in  FIG. 5 . More specifically,  FIG. 5  is a side view of embodiments of the chain tensioning systems  40  where the load cell  60  is disposed below a base  70  of the chain adjuster device  42 . Because the figure includes like element with  FIG. 4 , the like elements are depicted using like numbers. As depicted for example only, in some embodiments it may be beneficial to dispose the load cell  60  below the chain adjuster device  42 . In these embodiments the load cell  60  may measure a desired load when the chain adjuster device  42  is actuated via the base  70 . It is also to be noted that in some embodiments, the chain adjuster device  42  may include a load cell  60  already built-in, for example, in the ram  52 , or in any other portion or component of the chain adjuster device  42 . As mentioned earlier, the load cell  60  may then be used to measure a loading as the chain adjuster device  42  is used to tension the chain  24 . 
     Turning now to  FIG. 6 , the figure illustrates an embodiment of a control system  80  that may be used to automate or to partially automate the application of the chain adjuster device  42 . The control system  80  may be included in the chain tensioning systems  40  and may include one or more processors  82  and a memory  84 . The memory  84  may store computer code or instructions executable via the processor(s)  82 . The control system  80  may also include a human machine interface (HMI)  86  suitable for receiving inputs and for providing certain displays, such as load measurements. In the depicted embodiment, the control system  80  may be communicatively coupled to the load cell  60  and/or operatively coupled to the chain adjuster device  42 . In full automated use, the user may use the HMI  86  (e.g., that may include a display) to enter a desired loading value and may the initiate chain  24  tensioning operations. The control system  80  may then actuate the chain adjuster device  42  to move the ram  52  in the upward direction  44 . 
     As the ram  52  abuts against the against the take up spacer  54 , the load cell  60  may provide signals to the control system  80  representative of the load being applied by the chain adjuster device  42 . The control system  80  may then continue actuating the ram  52  until a desired load is achieved. Once the desired load is achieved, the control system  80  may stop actuation of the ram  52  and provide a log of the chain tensioning activity, including load applied. The user may then secure the systems  20  as mentioned above to maintain the desired chain  24  tension, and then the control system  80  may be used to lower the ram  52  to a stowing position. The chain adjuster device  42  may be driven by hydraulic power (e.g., hydraulic jack), electric power, and so on, controllable via the control system  80  to move the ram  52  up and/or down. 
     In a semi-autonomous mode, the control system  80  may be used to provide indication of a desired loading while the user may manually actuate the chain adjuster device  42  to move the ram  52  in the upward direction  44 . That is, the user may actuate the piston assembly  50  manually but the control  80  may monitor the loading as the ram  52  abuts against the take up spacer  54 . Once the desired loading is achieved, the HMI  86  may provide a visual and/or audio indication that the loading is now representative of a “good” chain  24  tension. For example, lights may be used, where green represents the good loading, yellow represents a smaller than desired loading, and red represents no loading or too much loading. The user may monitor the lights as they start red, go to yellow when the ram  52  abuts against the take up spacer  54 , and stop actuating the chain adjuster device  42  once the lights go green. Likewise, sound, including voice output, may provide similar feedback. 
       FIG. 7  is a flowchart depicting an embodiment of a process  100  suitable for chain tensioning the screen filter  10 . The process  100  may be implemented as computer code or instructions stored in the memory  84  and executable by the processor  82 . In the depicted example, the process  100  may first position (block  102 ) the loading cell  60 . For example, the load cell seat assembly  58  having the loading cell  60  may be disposed on top of the ram  52  of the chain adjuster device  42 . The process  100  may then actuate (block  104 ) the chain adjuster device  42 . For example, the control system  80  may be used to provide hydraulic power, electric power, compressed air, and so on, to the chain adjuster device  42  to actuate the chain adjuster device  42  (e.g., move the chain adjuster device  42  up and/or down). Likewise, a human operator may manually actuate (block  104 ) the chain adjuster device  42  via the piston assembly  50 . 
     The process  100  may then monitor (block  106 ) loading as the ram  52  abuts against the take up spacer  54 . For example, the process  100  may use the one or more load cells  60  to monitor loading as the ram  52  moves in the upwardly direction  44 . Once a desired load is reached, the process  100  may then stop (block  108 ) actuating the chain adjuster device  42 . The desired load may be provided by the manufacturer of the screen filter  10  and may take into account hours of operation. For example, at table that lists a desired load based on how many hours the chain  24  has been used after installation and/or after the latest tensioning activity may be provided. The process  100  may then secure (block  110 ) the chain  24  and related systems, e.g., system  20  via bolts, screws, fasteners, and so on. The process  100  may then lower the ram  52  once the chain  24  and related systems are secured (block  110 ). By providing for improved chain tensioning systems and methods, the techniques described herein may enable a more efficient operation of the screen filter  10 . 
     Other chain adjuster devices may be used. For example, and turning now to  FIG. 8 , the figure is a side view illustrating an embodiment of the screen filter  10  that includes a chain adjuster device  180 . In the depicted embodiment, a drive shaft  201  used to drive the chain  24  may be moved via tensioner(s)  202  included in the chain adjuster device  180 . For example, the drive shaft  201  may be disposed on a slide plate  204  that slides with respect to a fixed bracket assembly  184 . Sliding the slide plate  204  in a direction  186  may thus increase tension on the chain  24 . 
       FIG. 9  illustrates two of the chain adjuster devices  180  disposed on opposite sides of the screen filter  10 . As mentioned earlier the chain adjuster devices  180  may adjust chain tensioning by moving the shaft  201 . Movement of the shaft  201  in the direction  186  may increase chain  24  tension. It is also to be noted that the chain adjuster devices  42  and  180  operate while the screen filter  10  is off. The user may tension a first side B of the screen filter  10 , and then move to an opposite side C of the screen filter  10  and tension the opposite side. 
       FIG. 10  is a side sectional view of and embodiment of the chain adjuster devices  180  illustrating further details. The tensioner  20  includes a bearing  203  attached to the drive shaft  201  and mounted to the slide plate  204  which moves within a guide way  205  in the frame of the take up. The slide plate rest on a washer  206  which in turn rests on a nut  207 . The position of the nut is controlled by a threaded rod (acme or otherwise)  208  to which it may be pinned. A nut  209  may be attached to the tensioner frame that the threaded rod  208  passes through. Therefore as the rod turned the position of the nut that the slide plate ultimately rest on changes. An additional nut  210  and washer  211  may also be provided to lock the position of the threaded rod  208 . 
     The slide plate  204  may rest on a sensor  212 . The sensor  212  may be a force transducer, e.g., Load cell, Donut Load cell, Load Washer, and/or or Strain Gauged hollow cylinder, which in turn may rest on a washer  206 . The washer then in turn rest on a nut. The tensioners have a bearing  203  attached to the drive shaft and mounted to a slide plate  204  which moves within a guide way  205  in the frame of the take up. The slide plate  204  may rest on the sensor  212  which in turn may rest on the washer  206 . The washer  206  may then in turn rest on a nut  207 . The position of the nut  207  is controlled by a threaded rod (acme or otherwise)  208  to which it may pinned. A nut  209  may be attached to the tensioner frame that the threaded rod  208  passes through. Therefore as the rod  208  turns the position of the nut  207  that the slide plate  204  ultimately rest on changes. An additional nut  210  and washer  211  is provided in order to lock the position of the threaded rod. That is, in the embodiment viewed in  FIGS. 8-10 , tensioning may be provided via threaded bolts and nuts, and a slide plate (e.g., plate  204 ) may abut against the sensor  212  to measure a loading. It is to be noted that the sensor  212  may be used in lieu of or alternative to the load cell  60 . A display may be used to display a value representative of the force measured by the load cell  60  and/or all sensors described herein, such as pressure values and/or torque values. For example, the load cell  60  and/or all sensors described herein may be used to drive a display, e.g., via a Wheatstone bridge, the control system  80 , to view the values as the user tensions the chain. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.