Drainage systems employing preassembled drainage elements

Abstract

Pairs of preassembled drainage units are disposed in the bottom of a trench in laterally spaced apart relation with each drainage unit having an integral flap extending outwardly into overlapping relation with the flap of an adjacent drainage unit to form a chamber below the flaps and between the drainage units. An adapter can be used at one end of the drainage units to space the drainage units apart and to seal off the end from the entry of dirt and debris.

1 . A drainage system comprising at least one pair of preassembled drainage units disposed in the bottom of a trench in laterally spaced apart relation, each said drainage unit having an integral flap extending outwardly thereof into overlapping relation with said flap of an adjacent drainage unit to form a chamber below said flaps and between said drainage units; and
 a layer of backfill disposed over said drainage units and said flaps.   
   
   
       2 . A drainage system as set forth in  claim 1  wherein said flaps are secured together to maintain a spacing between said drainage units. 
   
   
       3 . A drainage system as set forth in  claim 1  wherein each said drainage unit includes a sleeve having an upper peripheral portion formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering said drainage unit, a lower peripheral portion of netting and a mass of light weight synthetic aggregate disposed within said sleeve. 
   
   
       4 . A drainage system as set forth in  claim 3  further comprising a perforated pipe extending through said mass of aggregate of at least one of said drainage units. 
   
   
       5 . A drainage system as set forth in  claim 3  further comprising a perforated pipe extending through said space between said drainage units. 
   
   
       6 . A drainage system as set forth in  claim 3  further comprising an adapter at one end of said drainage units to space said drainage units apart and to seal off said one end of said drainage units from the entry of dirt and debris. 
   
   
       7 . A drainage system as set forth in  claim 6  further comprising a perforated pipe passing through said adapter into the space between said drainage units. 
   
   
       8 . A drainage system as set forth in  claim 1  further comprising a bridge disposed in parallel between said drainage units to support said backfill. 
   
   
       9 . A drainage system as set forth in  claim 8  wherein said bridge is arch-shaped and perforated to allow the passage of water. 
   
   
       10 . A drainage system as set forth in  claim 8  wherein said bridge is placed loosely on top of said overlying flaps  14  with ends of said bridge abutting said respective drainage units. 
   
   
       11 . A drainage system as set forth in  claim 10  wherein said bridge has longitudinally extending ends of the bridge turned in one of an outwardly and inwardly directed direction. 
   
   
       12 . A preassembled drainage assembly comprising at least one pair of preassembled drainage units, each said drainage unit having an integral flap extending outwardly thereof into overlapping secured relation with said flap of an adjacent drainage unit to secure said drainage units together. 
   
   
       13 . A preassembled drainage assembly as set forth in  claim 12  wherein each said drainage unit includes a sleeve having an upper peripheral portion formed by a membrane material that allows for the passage of water while retaining fine particles and soil from entering said drainage unit, a lower peripheral portion of netting and a mass of light weight synthetic aggregate disposed within said sleeve. 
   
   
       14 . A preassembled drainage assembly as set forth in  claim 13  wherein each flap is formed by overlying longitudinal edges of said peripheral portions of a respective drainage unit and extends along the length of a respective drainage unit.