Sewer Vent

Abstract

A sewer vent 1 including structure 3 defining a flow path along which air entering the sewer travels upwardly past a valve element 4 . The valve element is configured to sink in air to form a seal to prevent gas escaping from the sewer, and float in water to form a seal to prevent water entering the sewer.

1 . A sewer vent including structure defining a flow path along which air entering the sewer travels upwardly past a valve element, wherein the valve element is configured to
 sink in air to form a seal to prevent gas escaping from the sewer; and   float in water to form a seal to prevent water entering the sewer.   
     
     
         2 . The vent of  claim 1  wherein the valve element is or includes a downwardly open vessel portion. 
     
     
         3 . The vent of  claim 1  wherein the valve element has a waist encircled by the structure to retain the valve element. 
     
     
         4 . The vent of  claim 3  wherein the encircling structure includes or carries a resilient portion for engaging the valve element to form each of the seals. 
     
     
         5 . The vent of  claim 1  including an overflow relief mechanism. 
     
     
         6 . The vent of  claim 5  wherein the overflow relief mechanism includes a mounting arrangement, by which the vent is mountable, configured to permit the vent to be lifted by rising liquid. 
     
     
         7 . The vent of  claim 6  including a float for lifting the vent. 
     
     
         8 . The vent of  claim 6  wherein the mounting arrangement includes an upwardly open tube in which the vent is receivable and relative to which the vent may be so lifted. 
     
     
         9 . The vent of  claim 8  and the upwardly open tube.