Abstract: Low density and acoustically absorbing panels are produced by consolidation in a mold of a heated part of a pre-cut, lofty, semi-finished product containing polypropylene fibers and reinforcing fibers and having an air pore content of 20 to 80 vol.-% wherein overlapping with the periphery of the pre-cut part are heated strips of polypropylene optionally containing up to 60 wt.-% reinforcing fibers, but containing 5 vol.-% or less of air pores.

Abstract: Low density and acoustically absorbing panels are produced by consolidation in a mold of a heated part of a pre-cut, lofty, semi-finished product containing polypropylene fibers and reinforcing fibers and having an air pore content of 20 to 80 vol.-% wherein overlapping with the periphery of the pre-cut part are heated strips of polypropylene optionally containing up to 60 wt.-% reinforcing fibers, but containing 5 vol.-% or less of air pores.

Abstract: A device is suggested wherein the work piece finishing chamber (31) serves simultaneously as a mixing chamber for mixing the gas components, and wherein a gas deceleration stage (47) is integrated in chamber block (30) between chamber (31) and a spark plug (54). The gas deceleration stage (47) is provided with labyrinth like extending bores (49,50,51). The combustion residues generated in the work piece finishing chamber (31) cannot reach spark plug (54) in view of the gas deceleration stage (47). Thus, a contamination of the spark plug (54) being disposed in block (30) is substantially eliminated.