Leaching chamber having sidewall with fenced louvers

Abstract

A corrugated thermoplastic leaching chamber has sidewall louvers that define sidewall slot openings. Each louver comprises an outward extending canopy, a cap integral with the outer end of the canopy, having a down slope greater than the slope of the canopy, and a preferably concave fence at the inner end of the canopy, for inhibiting ingress of soil. The chamber may be made by first thermoforming sheet material, preferably two-layer PET plastic sheet to the shape of the chamber, followed by mechanically cutting and deforming the sidewall, to create the opening and the fence.

What is claimed is: 
     
         1 . A method of forming a corrugated thermoplastic leaching chamber having an arch shape cross section, wherein the method comprises:
 thermoforming a plastic sheet to form a chamber precursor having a base flange, a top, a sidewall and corrugations,
 wherein the chamber precursor includes a plurality of alternating peak corrugations and valley corrugations running transverse to the length of the chamber and a plurality of undulations along at least one of the plurality of peak corrugations; and, 
   cutting and deforming the sidewall of the chamber precursor at the location of each undulation, so a portion of the peak corrugation moves inwardly toward the center of the chamber to form a plurality of louver pairs,
 wherein one or more of the plurality of louver pairs define a slot opening in the peak corrugation and wherein each louver includes a fence at the inner portion of the louver. 
   
     
     
         2 . The method of  claim 1 , further comprising,
 shaping each undulation to include,
 a canopy, wherein the canopy extends transversely to the width of the chamber and includes a canopy inner end and a canopy outer end, 
 a cap integral with the canopy outer end, wherein the cap is sloped downwardly relative to the canopy, and 
 a subwall that extends upwardly from the inner end of the canopy. 
   
     
     
         3 . The method of  claim 1 , wherein cutting and deforming includes pushing the subwall inwardly to form the fence and slot opening. 
     
     
         4 . The method of  claim 3 , wherein the fence has ends which are connected to the sides of the peak corrugation and which are curved in both a vertical plane and a horizontal plane of the chamber. 
     
     
         5 . The method of  claim 1 , wherein the fence includes an upper edge which is concave as projected into the horizontal base plane of chamber. 
     
     
         6 . The method of  claim 1 , further including forming the plastic sheet used to make the chamber precursor by adhesively bonding a first plastic layer to a second plastic layer. 
     
     
         7 . The method of  claim 6 , wherein the plastic sheet comprises polyethylene terephthalate (PET). 
     
     
         8 . A corrugated plastic chamber having an arch shaped cross section, opposing sidewalls and opposing side base flanges that run lengthwise along the chamber, wherein the opposing sidewalls extend upwardly the opposing side base flanges to a top portion of the chamber, wherein each of the opposing sidewalls comprise:
 a plurality of alternating peak corrugations and valley corrugations running transverse to the length of the chamber, wherein each of the plurality of peak corrugations include arch-curving sides and a plurality of louvers, wherein each of the plurality of louvers includes a fence at an inner portion of the louver, runs lengthwise within the peak corrugation and defines an opening, wherein each louver includes,
 a canopy, wherein the canopy extends transversely to the width of the chamber and includes a canopy inner end and a canopy outer end, 
 a cap integral with the canopy outer end, wherein the cap is sloped downwardly relative to the canopy, and 
 a subwall that extends upwardly from the inner end of the canopy. 
   
     
     
         9 . The chamber of  claim 8 , wherein each opening is slot shaped. 
     
     
         10 . The chamber of  claim 8 , wherein the ends of each fence are connected to the sides of the peak corrugation. 
     
     
         11 . The chamber of  claim 8 , wherein the upper edge of each fence has a concave shape, as projected into a horizontal plane. 
     
     
         12 . The chamber of  claim 8 , wherein the fence includes opposing end portions and wherein the opposing end portions are curved in both a vertical plane and a horizontal plane of the chamber. 
     
     
         13 . The chamber of  claim 8 , wherein the fence includes an upper edge and has a concave shape when projected into a vertical center plane. 
     
     
         14 . The chamber of  claim 8 , wherein the angle between the canopy and the cap is in the range of about 20 degrees to about 80 degrees when measured in a plane that is perpendicular to a lengthwise center plane of the chamber. 
     
     
         15 . The chamber of  claim 8 , wherein the canopy includes a top surface and wherein the angle of the top surface is in the range of about 0 degrees to about 20 degrees when measured in a plane which is perpendicular to a lengthwise center plane of the chamber. 
     
     
         16 . The chamber of  claim 8 , wherein the chamber is at least partially constructed from polyethylene terephthalate (PET). 
     
     
         17 . The chamber of  claim 8 , wherein the PET material comprises a first layer and a second layer, the layers joined to each other by an adhesive.