Multi-purpose lid for septic tank and associated riser

Abstract

A kit, and an assembly formed with components of the kit, comprises a fitting for the top of a septic tank or water tank, one or more frusto-conical rings shaped to interconnect with an identical ring to form an undulating wall riser that extends upwardly from the tank top fitting, and a lid. The lid is shaped for multi-purpose use: closing off the opening of either the large end or the small end of a ring/riser—whichever is uppermost, or closing off the fitting when there is no riser. Joints between the rings of the riser, and between a ring/riser and the fitting of a tank, are held together by latching tabs and/or screws. A fitting may be integral with a tank top.

1 - 22 . (canceled) 
     
     
         23 . A lid configured for sealing a subsurface fluid tank, the lid comprising:
 a top configured to cover an opening of the tank;   a circumscribing inner skirt extending downwardly from the top;   a circumscribing outer skirt extending downwardly from the top, wherein a diameter of the circumscribing outer skirt is larger than a diameter of the circumscribing inner skirt; and   a circumscribing middle skirt between the circumscribing inner skirt and the circumscribing outer skirt extending downwardly from the top, wherein the circumscribing middle skirt is configured to engage a gasket located in a fitting of the opening of the tank.   
     
     
         24 . The lid of  claim 23 , wherein the top is flat. 
     
     
         25 . The lid of  claim 23 , wherein the top is convex. 
     
     
         26 . The lid of  claim 23 , wherein the lid forms a seal with the gasket located in the fitting of the opening of the tank. 
     
     
         27 . The lid of  claim 23 , wherein the tank comprises a septic tank. 
     
     
         28 . The lid of  claim 23 , wherein the opening of the tank comprises an opening in a riser connected to the tank. 
     
     
         29 . The lid of  claim 23 , wherein the gasket comprises an O-ring. 
     
     
         30 . The lid of  claim 23 , wherein the lid is made of thermoplastic. 
     
     
         31 . The lid of  claim 23 , wherein the fitting of the opening of the tank comprises:
 a flange having a rim defining an opening of the fitting;   a web having a top surface running radially inward from the flange to the rim;   a circumscribing first ridge on the web top surface in proximity to the rim; and   a circumscribing second ridge on the web top surface, wherein a diameter of the circumscribing second ridge is larger than a diameter of the circumscribing first ridge.   
     
     
         32 . The lid of  claim 31 , wherein the circumscribing first ridge or the circumscribing second ridge comprises a gasket material. 
     
     
         33 . The lid of  claim 31 , wherein the fitting further comprises a step where the flange meets the web. 
     
     
         34 . The lid of  claim 31 , wherein the fitting further comprises a first skirt and a second skirt, wherein the first skirt and the second skirt extend downwardly from the web. 
     
     
         35 . The lid of  claim 31 , wherein a height of the second ridge is larger than a height of the first ridge.