Sewer overflow relief device

Abstract

A sewer overflow relief device for mounting at a top end of a sewer overflow relief pipe includes a top cover having at least one outside air intake and an air flow control mechanism for controlling the flow of outside air into the sewer overflow relief pipe. In use, the device prevents outside water from entering the sewer and the device may be ejected from the sewer overflow relief pipe by sewage pressure pushing against the device, thereby allowing the sewer overflow relief pipe to overflow.

1 .- 9 . (canceled) 
   
   
       10 . A sewer overflow relief device for mounting at a top end of a sewer overflow relief pipe, the device comprising:
 a top cover having an upper surface, the upper surface having at least one outside air intake; and   air flow control means for controlling the flow of outside air into the sewer overflow relief pipe;   wherein, in use, the device prevents outside water from entering the sewer and the device may be ejected from the sewer overflow relief pipe by sewage pressure pushing against the device, thereby allowing the sewer overflow relief pipe to overflow.   
   
   
       11 . The sewer overflow relief device according to  claim 10 , wherein the upper surface is a dome. 
   
   
       12 . The sewer overflow relief device according to  claim 10 , wherein the air flow control means comprise a one-way air valve having an upstream side in fluid connection with the at least one outside air intake and having a downstream side in fluid connection with the sewer overflow relief pipe;
 wherein the valve is oriented, when the device is oriented in an in-use orientation, with the upstream side at a lower level than the downstream side; and   wherein the valve is operable to allow passage of air when pressure on the downstream side is lower than on the upstream side, whereby outside air is admitted into the sewer overflow relief pipe.   
   
   
       13 . The sewer overflow relief device according to  claim 10 , wherein the at least one outside air intake is, when the device is oriented in an in-use orientation, located at a level higher than the level of the top end of the sewer overflow relief pipe. 
   
   
       14 . The sewer overflow relief device according to  claim 10 , further comprising
 a body of circular cross section for insertion into the top end of the sewer overflow relief pipe, the side walls of the body being sized to provide a close fitting arrangement with an internal wall of the top end of the sewer overflow relief pipe so as to prevent egress of sewer gas;   wherein the top cover is fixed to the body and has the same diameter as the outer diameter of the top end of the sewer overflow relief pipe, whereby the device is difficult to manually remove from the sewer overflow relief pipe.   
   
   
       15 . The sewer overflow relief device according to  claim 10 , further comprising
 a float for engaging against the device;   wherein, in use, the device may be ejected from the sewer overflow relief pipe by sewage pressure pushing against the float.   
   
   
       16 . The sewer overflow relief device according to  claim 10 , wherein the upper surface is polyhedral. 
   
   
       17 . The sewer overflow relief device according to  claim 10 , wherein, when the device is oriented in an in-use orientation, the at least one outside air intake is located in a raised position higher than the outer perimeter of the top cover.