A sintered metal fiber medium as subject of the invention comprises at
least a first metal fiber layer providing a first outer surface to the
sintered metal fiber medium. The first metal fiber layer comprises metal
fibers with an equivalent diameter D1. The medium has a mean flow pore
size of less than 2 times the equivalent diameter D1. The metal fibers in
the first metal fiber layer in the sintered metal fiber medium have a
ratio of average fiber length L1 over diameter (L1/D1) which is
preferably less than 110.