Patent ID: 7771503

Claim:
A method of manufacturing a stiffened tubular filter element for use in connection with gas turbines, the method comprising: centrally arranging a hollow tubular inner insert inside of a hollow tubular outer insert, securing a top flange at one end of said inserts to form a tubular filter element; applying a hardenable liquid in the form of multiple lines to an outer and/or an inner side of the filter element by discharging the liquid from one or more nozzles while moving at least one of the nozzles relative to the filter element to form multiple lines thereon, and further comprising: applying the liquid lines so as to form one or more rings which surround the tubular filter element, by fixing one or more nozzles in the longitudinal direction relative to the tubular filter element, while rotating the tubular filter element a number of rotations about a longitudinal axis thereof, and oscillating one or more nozzles with an oscillation greater than or equal to a distance between two rings and smaller than or equal to the length of the filter element, thereby applying and forming connecting lines between the rings, the rings and the connecting lines being in the form of a lattice; and, hardening the multiple liquid lines to form a stiffening net which is integral with the tubular filter element, thereby forming the stiffened tubular filter element.