Filtering device for collecting debris at the surface of bodies of water

Abstract

The invention relates to a filtering device comprising: a pipe ( 11 ) intended to be submerged in a flow of fluid, the pipe comprising an inlet opening ( 12 ) receiving the flow of fluid, and an outlet opening ( 13 ), a filter ( 14 ) arranged in the pipe and extending over an entire cross-section of the pipe, the pipe comprising a downstream section ( 11 b ) conveying the flow of fluid exiting the filter towards the outlet opening, the outlet opening having a surface area smaller than a surface area of the inlet opening, the surface areas being viewed in a plane perpendicular to a longitudinal axis (X) of the pipe.

1 . A filtering device comprising:
 a pipe intended to be immersed in a flow of fluid, and a filter arranged in the pipe to filter the fluid that enters the pipe, the pipe having:   an inlet opening receiving the flow of fluid,   an upstream section extending from the inlet opening and housing the filter,   an outlet opening, and   a downstream section extending from the filter as far as the outlet opening in order to convey the flow of fluid leaving the filter toward the outlet opening, the downstream section having a length greater than or equal to the length of the upstream section, the outlet opening having a surface area less than a surface area of the inlet opening, the surface areas being considered in a plane perpendicular to a longitudinal axis of the pipe.   
     
     
         2 . The filtering device as claimed in  claim 1 , wherein the upstream section has, in a plane passing through the longitudinal axis of the pipe, an internal profile which, with the direction of the flow, makes a zero angle or angle comprised between 0 and 16° toward the longitudinal axis of the pipe. 
     
     
         3 . The filtering device as claimed in  claim 1 , wherein the pipe has a bulge on its exterior face around the inlet opening, the bulge having, at the inlet opening, a tangent that makes an angle greater than 45° with respect to the longitudinal axis of the pipe. 
     
     
         4 . The filtering device as claimed in  claim 1 , wherein the downstream section has, in a plane passing through the longitudinal axis of the pipe, an internal profile that is rectilinear or curved and that, with the direction of the flow, makes an angle of between 0 and 20°. 
     
     
         5 . The filtering device as claimed in  claim 1 , wherein the surface area of the outlet opening is tailored such that the velocity of the flow of fluid at the pipe outlet is comprised between 80 and 110% of the velocity of the fluid around the outlet opening. 
     
     
         6 . The filtering device as claimed in  claim 5 , wherein the surface area of the outlet opening is comprised between 0.1 and 5 times the total surface area for the passage of the fluid through the filter. 
     
     
         7 . The filtering device as claimed in  claim 1 , wherein the pipe has a cross section of circular, elliptical, trapezoidal, triangular, polygonal, square or rectangular shape or of a shape made up of these shapes. 
     
     
         8 . The filtering device as claimed in  claim 1 , comprising a grating positioned in front of the filter and having a surface area for the passage of the flow of fluid that is greater than the passage surface area of the filter, the grating being positioned in the pipe, or else in front of the opening of the pipe so as to act as a filter and/or a breakwater, the grating optionally being associated with a cleaning or suction device for removing the debris caught by the grating. 
     
     
         9 . The filtering device as claimed in  claim 1 , comprising at least a filter exhibiting one of the following features:
 the filter has a cone or pyramid shape,   the filter has a cone or pyramid shape and a debris discharge opening at the vertex of the cone or pyramid shape,   the filter is planar and arranged perpendicular to the longitudinal axis (X) of the pipe,   the filter is planar and arranged inclined with respect to the longitudinal axis of the pipe,   the filter exhibits a plurality of juxtaposed grooves of V-shaped normal cross section,   each face of the filter exhibits a convex part and a concave part,   the filter is made up of parallel rods, and   the filter comprises rods or meshes that are profiled so as to reduce the drag of the filter.   
     
     
         10 . The filtering device as claimed in  claim 1 , wherein the filter is associated with a cleaning device or with a suction device, to remove the debris caught by the filter. 
     
     
         11 . The filtering device as claimed in  claim 1 , comprising a member configured to push the device upward when the device is fully immersed in the body of water, and a member configured to push the device downward when the device is not fully immersed in the body of water. 
     
     
         12 . A method for collecting solid debris near the surface of a body of water, the method comprising the steps of:
 providing a filtering device as claimed in  claim 1 , and   associating the filtering device with a structure that keeps the pipe of the filtering device immersed at the surface of the body of water in a flow of water, or else   associating the filtering device with a ship so as to keep the pipe of the filtering device immersed at the surface of the body of water, and moving the ship at a cruising speed so as to generate a flow of water in and around the pipe of the filtering device.   
     
     
         13 . The method as claimed in  claim 12 , comprising a step of collecting debris in a reservoir. 
     
     
         14 . The method as claimed in  claim 12 , wherein the flow of water has a velocity of between 1 and 15 m/s. 
     
     
         15 . The filtering device as claimed in  claim 4 , wherein the downstream section has, in a plane passing through the longitudinal axis of the pipe, an internal profile that is rectilinear or curved and that, with the direction of the flow, makes an angle of between 4 and 9°.