Liquid drainage system for flat surfaces

Abstract

The drainage system is for flat surfaces, especially roofs, terraces, baths, car parks, designed for drainage of water or other liquids from the area of the surface. The drainage system includes at least one rectangular plate, the lower surface of which is substantially flat and the upper surface is non-flat. At points on the upper surface, the inclination of at least a part of the upper surface is smoothly variable.

We claim: 
     
         1 . A drainage system for flat surfaces, the system comprising;
 at least one rectangular plate, the lower surface of which is flat and the upper surface is non-flat,   wherein, at points on the upper surface, at least on a part of the upper surface, the inclination of the upper surface is smoothly variable.   
     
     
         2 . The drainage system, according to  claim 1 , wherein the upper surface is shaped as a slice of the lateral surface of an elliptical cone, and
 wherein the points on the upper surface have an inclination smoothly varying from the smallest inclination for the longer axis of the cone base to the largest inclination for the shorter axis of the cone base.   
     
     
         3 . The drainage system according to  claim 2 , wherein the elliptical cone is a straight cone. 
     
     
         4 . The drainage system according to  claim 2 , wherein the elliptical cone is an inclined cone. 
     
     
         5 . The drainage system according to  claim 2 , further comprising: at least one plate, the upper surface of which is shaped as a cylinder section or the plate is wedge-shaped. 
     
     
         6 . The drainage system according to  claim 2 , further comprising: at least one plate, the upper surface of which is flat. 
     
     
         7 . The drainage system according to  claim 1 , wherein the upper surface of the plate is shaped as a slice of the side surface of a pyramid, the base of which is a rectangle with rounded corners, and
 wherein the points on the upper surface have a slope varying from the smallest slope at the shorter side of the pyramid base to the largest slope at the longer side of the pyramid base.   
     
     
         8 . The drainage system according to  claim 1 , wherein at least one plate is square. 
     
     
         9 . The drainage system according to  claim 1 , further comprising: a flat plate adapted for or in which a drain hole is provided. 
     
     
         10 . The drainage system according to  claim 1 , further comprising: at least two plates adapted to provide a drain hole or in which a drain hole is provided at an interface between said plates. 
     
     
         11 . The drainage system according to  claim 1 , wherein at least one plate has a mark made on the upper surface to indicate the direction of drainage of water or other liquid. 
     
     
         12 . The drainage system according to  claim 11 , wherein the mark is comprised of an arrow or arrowhead. 
     
     
         13 . The drainage system according to  claim 11 , wherein the mark is comprised of a line or strip of variable width. 
     
     
         14 . The drainage system according to  claim 11 , wherein the mark is located at the side of the plate with the smallest thickness.