GB1002286A - Improvements in apparatus for forming a mat of fibres - Google Patents

Abstract

1,002,286. Lap forming. WEYERHAEUSER CO. May 25,1962, No. 20243/62. Headings D1N and D1R. In an apparatus for forming a mat 32 of fibres on a travelling surface 10 by depositing the fibres thereon from a pneumatic fibre disperser 15 having a semi-cylindrical dispersing head 16, the head has a main group of holes 17 of uniform size of such a dimension that the coarser fibres will be dispersed therethrough, and a second group of holes 18 of smaller uniform size of such a dimension that only the finer fibres will be dispersed therethrough. Fibres enter the disperser 15 at above atmospheric pressure and are wiped through the holes 17 and 18 by the nylon bristle brushes 30 on the blades of a rotor 19 which is rotating at a speed between 175 and 600 r.p.m. They settle on the endless wire screen 10 as it passes over a suction box 13. The fine fibres, from the holes 18, form a smooth uniform top layer on the mat, despite the tendency of the air stream 25 to sweep the lighter fibres to the back of the chamber 21. The group of holes 18 are either spaced from the holes 17 or else separated by a baffle 31, Fig. 4 (not shown), on the outside or the head. To obtain smooth surfaces on each side of the mat a single disperser may be used with fine holes at the rear and front, or three dispersers used, with fine holes in the front of the front one and in the rear of the rear one (Fig. 2 not shown). Suitable values of the size and separation of the holes 17, 18 are given.