Patent Publication Number: US-2016236116-A1

Title: Hinged launder cover system for improved access to the weir

Description:
BACKGROUND 
     1. Field of the Invention 
     The present arrangement is directed to a waste treatment tank launder cover arrangement. More particularly, the present arrangement is directed to a cover and associated mounting arrangement for a launder channel cover. 
     2. Description of Related Art 
     The primary and secondary clarifiers in most wastewater treatment plants are large circular tanks designed to allow solids to settle out of the sewage influent and collect the clean water in an effluent channel, or launder channel, built around the periphery at the top of the clarifier. This water is further processed before being returned to the environment. 
     Algae is a major nuisance that often forms in the nutrient rich effluent that collects in and around the clarifier launder channel. A weir is a common component of such launder channels, acting to control the flow of clean water into the launder and further assisting in preventing solids that have not settled from entering the launder channel. The algae often collects on the weir and launder surfaces, impacting hydraulic flow over the weir and passing downstream throughout the plant to clog filters and other equipment. Cleaning algae from the launder surfaces is an expensive, labor-intensive chore in treatment plants. 
     One of the most effective means of reducing or eliminating algae growth is the installation of a cover system that extends over the launder and weir and keeps incident sunlight from reaching the surfaces of the launder and weir, thus inhibiting the growth of the algae. 
     Prior art launder cover systems for algae control as shown for example in prior art  FIG. 1  typically have a series of two-piece cover modules each made up of a mounting section and a cover section connected by a continuous stainless steel hinge. The mounting section is supported by a bracket that fastens to the top of the weir wall and serves as the base for the hinged cover section. The cover section is configured to be opened toward the center of the tank and away from the operator standing on the outer tank wall to allow the operator to clean the weir with a hose and inspect the weir and launder for algae growth, debris, wear and other factors that can affect effluent system performance. Principal among these factors is the collection of rags and other debris that can become entangled in the V-notched “teeth” of the weft and impact hydraulic flow in the clarifier. 
     A major concern among users of this design is the fact that, depending upon the viewing angle of the operator, the hinge point of the cover is in front of the weir plate and can, and often does, block the operator&#39;s view of the weir and his ability to dean the weir with a hose or brush if required. In other words the hinge is located closer to the outer tank wall than the weir as shown in  FIG. 1 . 
     OBJECTS AND SUMMARY 
     The present arrangement overcomes the drawbacks by producing a novel cover mounting bracket arrangement for the mounting section of the cover module that is attached to the inner face of the weir wall so that the hinge point of the cover section can be moved inward towards the center of the tank relative to the prior art location so that it is between the weir and scum baffle. When the cover section is opened the weir is clearly visible from the tank wall and above without interference from the hinge area of the cover section. 
     To this end a waste treatment tank cover arrangement is provided having at least one cover module having a cover section, a mounting section, and a hinge, where the cover section is pivotably mounted to the mounting section, movable between a dosed position and an open position. At least one cover module mounting bracket arrangement has a first L-shaped bracket connected to an inner side of a launder channel wall and a U-shaped mounting bracket conned to the first L-shaped bracket and extending upward, where the U-shaped mounting bracket connects to and supports the mounting section of the cover module. The position of the mounting bracket and connected hinge are such that the position of the hinge is inboard relative to the location of the weir such that when the cover section is in an open position, the weir is exposed and not hidden beneath the mounting section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be best understood through the following description and accompanying drawings, wherein: 
         FIG. 1  is a prior art cut-away view of a launder channel and cover module; 
         FIG. 2  shows a launder channel with a cover module mounting bracket arrangement in accordance with one embodiment; 
         FIG. 3  shows a launder channel with scum baffle and scum baffle bracket arrangement in accordance with one embodiment; and 
         FIG. 4  shows a launder channel with a cover module mounting bracket of  FIG. 2  and scum baffle bracket arrangement of  FIG. 3  in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with one embodiment of the present arrangement,  FIG. 2  shows a typical cross section of a clarifier tank in the area of a launder channel. As shown, the clarifier tank has an outer tank wall T, a launder channel C and a launder channel inner wall CW. At the top of channel wall CW is a weir W. For the purposes of illustrating the salient features of the invention, it is assumed that the clarifier tank is a typical circular clarifier tank with a launder channel located at the upper outer circumference however the features of the present cover module mounting bracket arrangement may be implemented on other shaped launder channels and clarifier tanks. 
     As shown in  FIG. 2  a cover module  10  includes a cover section  12  and a mounting section  14  connected by a hinge  16 .  FIG. 2  shows cover module  10  in a closed position with the edge of cover module  12  resting against outer tank wall T. Cover section  12  is configured to be pivitoable about hinge  16  towards the center of the tank exposing the launder channel C and the weir W. Cover module  10  is typically constructed of molded fiber glass components with hinge  16  being made from metal.  FIG. 2  is a cut-away view of a circular clarifier tank and launder channel but it is understood that a typical tank will have many independently mounted cover modules  10  each about three (3) to four (4) feet in length of an arcuate shape so that the combination of cover modules  10  in totality completely cover the entire launder channel C. 
     As shown in  FIG. 2 , a cover module mounting bracket arrangement  20  is provided for supporting the other side of cover module  10  at the launder channel wall. Cover module mounting bracket arrangement  20  is made from a first L-shaped bracket  22  with its first side  22 A mounted flush against the inner side of the channel wall CW with the second side  22 B of the L-shaped bracket  22  extending inward perpendicular to the inner side of the channel wall CW for a given distance. Attached to second side  22 B of the L-shaped bracket is a U-shaped mounting bracket  24  with a first lower leg  24 A attached to second side  22 B of the L-shaped bracket, an upwardly extending leg  24 B and another perpendicular upper leg  24 C that is coupled to the underside of mounting portion  14  as shown in  FIG. 2 . 
     As shown in  FIG. 2  owing to the extension of L-shaped bracket  22  and lower and upper legs  24 A and  24 C, hinge  16  between cover section  12  and mounting section  14  is positioned inward with respect to weir W so that when cover section  12  is opened an operator standing on tank wall T would have a clear un-obstructed view of weir W. As shown in  FIG. 2 , the connection between the second side  22 B of the L-shaped bracket  22  and lower leg  24 A of cover mounting bracket  24  as well as the connection between upper leg  24 C of cover mounting bracket  24  and the underside of mounting section  14  are slidingly adjustable via bolt attachments  28  so to accommodate varying weir W locations so that hinge  16  is always inboard with respect thereto. 
       FIG. 2  shows a single cover mounting bracket  24  however it is understood that a number of such brackets  24  are disposed about the entire circumference of launder channel wall CW. In one example, each mounting section  14  is supported by two independent brackets  24  spaced apart from one another by a few feet along the circumference of launder channel wall  24 . More or less brackets  24  may be used per mounting section  14  as desired based on the size of cover modules  10  and the size of the clarifier tank. 
     To prevent confusion,  FIG. 3  separately illustrates a side view of a scum baffle  30  and scum baffle mounting bracket arrangement  32  with the mounting brackets  24  removed for clarity. A scum baffle is used to prevent solids from passing in launder channel C. Scum baffle bracket arrangement  32 , has a first L-shaped bracket  34  similar to L-shaped bracket  22  above, with a lower portion  34 A attached to the inner side of launder channel wall CW and a perpendicular portion  34 B extending inward. Attached to first L-shaped bracket  34  is a second L-shaped bracket  36  which likewise has a first perpendicular portion  36 A and then an upwardly extending portion  363 . The actual scum baffle  30  is attached to upwardly extending portion  36 B up towards mounting section  14 . As shown in  FIG. 3 , the top of baffle  30  extends upwards far enough to end just below the underside of mounting section and nested within a downturned flange  15  of mounting section  14  so as to essentially prevent all sunlight from reaching weir W. 
     As with  FIG. 2 , to be understood clearly,  FIG. 3  shows a single scum baffle  30  and bracket arrangement  32  however it is understood that a number of such baffles  30  and brackets  32  are disposed about the entire circumference of launder channel wall CW. In one example, the actual “baffle” is comprised of a plurality of baffles  30 , each arcuate in shape and extending around the entire inner circumference of launder channel wall CW. In one example, each section of baffle  30  may be supported by two independent brackets  32  spaced apart from one another by a few feet along the circumference of launder channel wall  24 , potentially interspersed between cover module brackets  24 , As with brackets  24 , more or less brackets  32  may be used per baffle  30  as desired based on the size of each component baffle  30  and the size of the clarifier tank. 
     The final  FIG. 4 , shows the combination of cover module mounting bracket  24  with scum baffle  30  (baffle brackets remove) so that the position relationship between the two can be seen. 
     In another embodiment, it is noted that an alternative arrangement for the mounting of scum baffle  30  (not shown) could include mounting scum baffle  30  to mounting section  14 , and/or putting a strap between the mounting section  14  and the scum baffle  30 . 
     While only certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes or equivalents will now occur to those skilled in the art. It is therefore, to be understood that this application is intended to cover all such modifications and changes that fall within the true spirit of the invention.