The invention relates to a crusher housing (67) which is provided with a lid member (69) that is provided with an inner lid lining face (82) that is positioned as closely as practical possible to the open rotor (72) creating essentially a sandwich rotor with a rotating rotor table and a stationary roof with minimum free space between the top side of the sliding members (85) and the inner lid lining face (82), which configuration provides the crushing chamber with a number of unique features in that vortex building and turbulence in the crushing chamber are severely limited, such that the particles are focused for accurate and undisturbed impact; increasing the reduction ratio, providing constancy to the breakage process - resulting in less oversize and less undersize, better shaping and a high degree of selectivity - and reduces wear along the feed opening and along the inner lid lining in dramatic way, saves on energy, and limits dust formation.