Endless flexible belt conveyor with a leaktight flexible cover belt

Endless flexible belt conveyor (1) operating in the shape of a deep semicircular trough provided with a flexible cover belt (2) consisting of a light textile support at least one side of which is coated with an elastomer or plastic polymer that is held in contact with said endless flexible belt conveyor (1) by pressure rollers (4) that move the two said belts (1, 2) at the same speed and enclose the transported materials, characterized

• in that flexible cover belt (2) is flat in the rest position, except for its longitudinal edges (7), and includes a width (a) related to width (L) of endless flexible belt conveyor (1) when it has a deep semicircular trough shape, at angle (δ) formed by said flexible cover belt (2) and operating, relative to the horizontal and to length (b) of continuous leaktight loop (8), by the following relation:
• 2 a = L · cos ⁢ ⁢ δ + 2 ⁢ b
• in that a leaktight device (5) between said belts (1, 2) is constituted on each longitudinal edge of said belts (1, 2 ) of said continuous leaktight loop (8), the width (c) of recess (9) of which matches thickness (e) or endless flexible belt conveyor (1) that grips each longitudinal edge (6) of said endless flexible belt conveyor (1) by automatically locking near loading zone (Zc),
• in that said leaktight device is disconnected near unloading zone (Zd) by becoming simply unhooked under the separation load exerted between said belts (1, 2) and trough opening angle (α) without any mechanical operation being required to create said disconnection.