Backflow prevention valve

Abstract

The backflow prevention valve comprises various embodiments for installation in a liquid conduit for the prevention of reverse flow therethrough. The valve is particularly well suited for installation in a fire hydrant, where it prevents the illicit backflushing of the water system with contaminants. The valve may be constructed for use with either dry barrel hydrants, i.e., where the water is drained from the hydrant when the water is shut off, or wet barrel hydrants, where water remains in the hydrant body at all times. The valve may be constructed with a cylindrical body or with a thinner ring for the body, depending upon the installation desired. Each embodiment includes a series of generally triangular leaves hinged about the inner circumference of the valve body, which close against the central control rod or against one another at their apices when water is not flowing therethrough.

1 . A backflow prevention valve, comprising: 
 a hollow cylindrical body having a first edge, a second edge opposite said first edge defining a length therebetween, and an inner periphery;    a plurality of rigid, generally triangular valve segments each having a base, a radially disposed first and second edge, and an apex, the first edge and the second edge of each of said valve segments having a mating, complementary configuration, the first and the second edge of adjacent said valve segments sealing with one another when said valve segments are closed; and    at least one flexible hinge extending inwardly from the inner periphery of said body and securing the base of each of said valve segments to said body.    
   
   
       2 . The backflow prevention valve according to  claim 1 , further including: 
 a first attachment flange extending radially outwardly from said first edge of said body; and    a second attachment flange extending radially outwardly from said second edge of said body.    
   
   
       3 . The backflow prevention valve according to  claim 1 , further including: 
 a first and a second control valve stem segment passing concentrically through said body;    a frangible coupling connecting said first and said second control valve stem segment;    said apex of each of said valve segments having a truncated tip; and    a seal extending from said truncated tip of each of said valve segments and sealing against said coupling when said valve segments are closed.    
   
   
       4 . The backflow prevention valve according to  claim 1 , wherein: 
 said at least one flexible hinge comprises a resilient material having a toroidal configuration with an outer peripheral body attachment portion and an inner peripheral valve segment attachment portion; and    a clamp plate having a toroidal configuration is secured to said first edge of said body, sandwiching said outer peripheral body attachment portion of said at least one flexible hinge between said first edge of said body and said clamp plate.    
   
   
       5 . The backflow prevention valve according to  claim 1 , wherein said apex of each of said valve segments has a pointed tip, bearing against one another when said valve segments are closed.  
   
   
       6 . The backflow prevention valve according to  claim 1 , further including: 
 a first lip and a second lip spaced apart therefrom disposed along said first edge of each of said valve segments, and defining a groove therebetween; and    a ridge disposed along said second edge of each of said valve segments, and sealing closely within the mating said groove of an adjacent one of said valve segments when said valve segments are closed.    
   
   
       7 . A backflow prevention valve, comprising: 
 a thin ring having a toroidal configuration defining an inner periphery;    a plurality of rigid, generally triangular valve segments each having a base, a radially disposed first and second edge, and an apex, the first edge and the second edge of each of said valve segments having a mating, complementary configuration, the first and the second edge of adjacent said valve segments sealing with one another when said valve segments are closed; and    at least one flexible hinge extending inwardly from the inner periphery of said ring and securing the base of each of said valve segments to said ring.    
   
   
       8 . The backflow prevention valve according to  claim 7 , further including an attachment flange extending radially outwardly from said ring.  
   
   
       9 . The backflow prevention valve according to  claim 7 , further including: 
 a first and a second control valve stem segment passing concentrically through said ring;    a frangible coupling connecting said first and said second control valve stem segment;    said apex of each of said valve segments having a truncated tip; and    a seal extending from said truncated tip of each of said valve segments and sealing against said coupling when said valve segments are closed.    
   
   
       10 . The backflow prevention valve according to  claim 7 , wherein: 
 said at least one flexible hinge comprises a resilient material having a toroidal configuration with an outer peripheral ring attachment portion and an inner peripheral valve segment attachment portion; and    a clamp plate having a toroidal configuration is secured to said ring, sandwiching said outer peripheral ring attachment portion of said at least one flexible hinge between said first edge of said ring and said clamp plate.    
   
   
       11 . The backflow prevention valve according to  claim 7 , wherein said apex of each of said valve segments has a pointed tip, bearing against one another when said valve segments are closed.  
   
   
       12 . The backflow prevention valve according to  claim 7 , further including: 
 a first lip and a second lip spaced apart therefrom disposed along said first edge of each of said valve segments, and defining a groove therebetween; and    a ridge disposed along said second edge of each of said valve segments, and sealing closely within the mating said groove of an adjacent one of said valve segments when said valve segments are closed.    
   
   
       13 . A hydrant having a backflow prevention valve installed therein, comprising in combination: 
 a hydrant barrel having a hollow interior and a base;    a hydrant standpipe disposed concentrically below said barrel;    a hydrant backflow prevention valve installed concentrically between said hydrant barrel and said hydrant standpipe, the valve having: 
 a valve housing having an open center concentric with said hydrant barrel and said hydrant standpipe, and having an inner periphery;  
 a plurality of rigid, generally triangular valve segments each having a base, a radially disposed first and second edge, and an apex, the first edge and the second edge of each of said valve segments having a mating, complementary configuration, the first and the second edge of adjacent said valve segments sealing with one another when said valve segments are closed; and  
 at least one flexible hinge extending inwardly from the inner periphery of said valve housing and securing the base of each of said valve segments to said valve housing.  
   
   
   
       14 . The hydrant and backflow prevention valve combination according to  claim 13 , wherein said valve housing comprises: 
 a hollow cylindrical body having a first edge, a second edge opposite said first edge defining a length therebetween, and an inner periphery;    a first attachment flange extending radially outwardly from said first edge of said body; and    a second attachment flange extending radially outwardly from said second edge of said body.    
   
   
       15 . The hydrant and backflow prevention valve combination according to  claim 13 , wherein said valve housing comprises a thin ring having a toroidal configuration with an inner periphery.  
   
   
       16 . The hydrant and backflow prevention valve combination according to  claim 13 , further including: 
 a first and a second control valve stem segment passing concentrically through said hydrant barrel, said hydrant standpipe, and said valve housing;    a frangible coupling connecting said first and said second control valve stem segment;    said apex of each of said valve segments having a truncated tip; and    a seal extending from said truncated tip of each of said valve segments and sealing against said coupling when said valve segments are closed.    
   
   
       17 . The hydrant and backflow prevention valve combination according to  claim 13 , wherein: 
 said at least one flexible hinge comprises a resilient material having a toroidal configuration with an outer peripheral valve housing attachment portion and an inner peripheral valve segment attachment portion; and    a clamp plate having a toroidal configuration is secured to said valve housing, sandwiching said outer peripheral valve housing attachment portion of said at least one flexible hinge between said valve housing and said clamp plate.    
   
   
       18 . The hydrant and backflow prevention valve combination according to  claim 13 , wherein said apex of each of said valve segments has a pointed tip, bearing against one another when said valve segments are closed.  
   
   
       19 . The hydrant and backflow prevention valve combination according to  claim 13 , further including: 
 a first lip and a second lip spaced apart therefrom disposed along said first edge of each of said valve segments, and defining a groove therebetween; and    a ridge disposed along said second edge of each of said valve segments, and sealing closely within the mating said groove of an adjacent one of said valve segments when said valve segments are closed.