We combined the ideas of the systems with plates and slurry trays to create long gutters with sloping walls of glass fiber reinforced polyester. The gutters consist of several elements which will be linked together until the total length of the slurry channel is reached. The elements are linked by a connection which is made in the elements during the production. To seal off both ends of the gutter, end pieces are produced, which will be linked to the other elements by the same kind of connection. These gutters can be provided with a cooling system.