Structural parts of machines, namely, conveyor belts, sieve conveyor belts, support belts, filter round plates, filter cartridges, filter cylinders, sieve cylinders and sieves, each made from wire cloth and wire grids; filters being parts of machines or motors; pressure leaf filters being machine parts for solid and liquid separation; mechanical filter presses being machine parts for use in the paper industry, the waste and refuse industry and the sewage industry; horizontal vacuum belt filters being machine parts for filtration of slurries, namely industrial, chemical and mineral sludge; filters being machine parts, namely, filters for filtering sand; machines for use in the food industry, namely, pulp washers and pulp filters; thickening machines, namely, sludge thickeners and sludge thickeners utilizing internal rakes