Subsurface drainage system

Abstract

The present invention is directed to a subsurface drainage system for a playing surface. The subsurface drainage system includes a subgrade, an intermediate layer disposed over the subgrade, a layer of semi-permeable filter fabric disposed over the intermediate layer, an upper permeable layer disposed over the layer of filter fabric and on which the playing surface is disposed, and a hydronic piping network disposed in the upper layer near the layer of filter fabric. The layer of filter fabric has a permeability less than the permeability of the intermediate layer and such that the layer of filter fabric functions as a perching layer to support a perched water table above the filter fabric. The hydronic piping network is positioned within the perched water table such that the water of the perched water table functions as a heat exchanger to facilitate heating and cooling of the upper layer upon the hydronic piping network being heated or cooled.

1 . A subsurface drainage system for a playing surface, comprising: 
 a subgrade;    an intermediate layer disposed over the subgrade and formed from at least one material to define a drainage blanket layer;    a layer of semi-permeable filter fabric disposed over the intermediate layer, the layer of filter fabric having a permeability less than the permeability of the intermediate layer and such that the layer of filter fabric functions as a perching layer to support a perched water table above the layer of filter fabric;    an upper permeable layer disposed over the layer of filter fabric and on which the playing surface is disposed; and    a hydronic piping network disposed in the upper layer near the layer of filter fabric so that the hydronic piping network is positioned within the perched water table such that the water of the perched water table functions as a heat exchanger to facilitate heating and cooling of the upper layer upon the hydronic piping network being heated or cooled.    
   
   
       2 . The subsurface drainage system of  claim 1  wherein the layer of filter fabric is a polyester spunbond non-woven fabric having a weight in a range of from about 110 gsm to about 150 gsm.  
   
   
       3 . The subsurface drainage system of  claim 1  wherein the subgrade is contoured to define one or more surfaces sloping down to points or lines of fluid collection.  
   
   
       4 . The subsurface drainage system of  claim 1  wherein the intermediate layer is formed at least one material selected from the group consisting of crushed stone, pea gravel, rubber particles, and combinations thereof.  
   
   
       5 . The subsurface drainage system of  claim 1  wherein the intermediate layer is a thermoplastic mat having a laterally extensive backing grid and a plurality of spaced tubular support members projecting from the backing grid whereby fluid may flow through the backing grid and the support members.  
   
   
       6 . The subsurface drainage system of  claim 1  wherein the upper layer is a root zone layer comprising at least one material selected from the group consisting of sand, organic matter, inorganic matter and combinations thereof.  
   
   
       7 . A subsurface drainage system for regulating the temperature of a root zone, comprising: 
 a semi-permeable filter fabric having a permeability such that the filter fabric functions as a perching layer to support a perched water table above the filter fabric;    a root zone layer disposed over the layer of filter fabric;    a natural turf layer disposed on the root zone layer; and    a hydronic piping network disposed in the root zone layer near the layer of filter fabric with the hydronic piping network positioned within the perched water table such that the water of the perched water table functions as a heat exchanger to facilitate heating and cooling of the root zone layer upon the hydronic piping network being heated or cooled.    
   
   
       8 . The subsurface drainage system of  claim 7  wherein the layer of filter fabric is a polyester spunbond non-woven fabric having a weight in a range of from about 110 gsm to about 150 gsm.  
   
   
       9 . A subsurface drainage system for regulating the temperature of an artificial turf, comprising: 
 a semi-permeable filter fabric having a permeability such that the filter fabric functions as a perching layer to support a perched water table above the filter fabric;    a permeable upper layer disposed over the layer of filter fabric;    an artificial turf layer disposed on the upper permeable layer; and    a hydronic piping network disposed in the upper permeable layer near the layer of filter fabric with the hydronic piping network positioned within the perched water table such that the water of the perched water table functions as a heat exchanger to facilitate heating and cooling of the upper permeable layer and thus the artificial turf layer upon the hydronic piping network being heated or cooled.    
   
   
       10 . The subsurface drainage system of  claim 9  wherein the layer of filter fabric is a polyester spunbond non-woven fabric having a weight in a range of from about 110 gsm to about 150 gsm.