Eductor

Abstract

An eductor having an air gap, a venturi structure, and a non-return valve located in the air gap. The non-return valve is removable and allows the eductor to be operated as an air gap eductor or a non-return valve eductor. A non-return valve cartridge for installing in to the air gap of an air gap eductor, so that the eductor can be operated as a non-return valve eductor. A method of retrofitting a non-return valve in an air gap eductor.

1 . An eductor comprising a venturi structure, an air gap across which in air gap operational mode a liquid jet is passed to the venturi structure and a removable non-return valve located in the air gap, whereby the eductor is convertible between air gap operational mode and non-return valve operational mode.  
   
   
       2 . An eductor according to  claim 1 , wherein in air gap operational mode the eductor has a nozzle to provide said liquid jet, the nozzle being removable and replaced by the non-return valve on conversion.  
   
   
       3 . An eductor according to  claim 1 , wherein the non-return valve has an outlet providing in use a fluid jet directed into the venturi structure.  
   
   
       4 . An eductor according to  claim 1 , wherein the non-return valve provides a sealed first flow path across the air gap when open for liquid flow to the venturi structure and provides a second flow path for back flow from the venturi structure into the air gap out of the non-return valve when said first flow path is closed.  
   
   
       5 . (canceled)  
   
   
       6 . (canceled)  
   
   
       7 . (canceled)  
   
   
       8 . (canceled)  
   
   
       9 . A method of adapting an air gap eductor having a venturi mixing portion and an air gap, comprising installing a non-return valve in said air gap.  
   
   
       10 . A method according to  claim 5 , wherein the air gap eductor comprises a nozzle for directing a water jet and the method comprises the step of removing the nozzle from the eductor.  
   
   
       11 . An eductor according to  claim 2 , wherein the non-return valve has an outlet providing in use a fluid jet directed into the venturi structure.  
   
   
       12 . An eductor according to  claim 2 , wherein the non-return valve provides a sealed first flow path across the air gap when open for liquid flow to the venturi structure and provides a second flow path for back flow from the venturi structure into the air gap out of the non-return valve when said first flow path is closed.  
   
   
       13 . An eductor according to  claim 3 , wherein the non-return valve provides a sealed first flow path across the air gap when open for liquid flow to the venturi structure and provides a second flow path for back flow from the venturi structure into the air gap out of the non-return valve when said first flow path is closed.