Abstract: A filter device for use in a pipeline flow system used in particular, but not essentially in milking installations comprises a filter housing (4,5) containing a plurality of filter elements (1a,1b,1c etc) of decreasing size in the flow direction for successively filtering and particles of decreasing size. Each filter element comprises a first filter mesh (1) and a second and coarser filter mesh (2) serving a support mesh positioned on the downstream side of each filter element. The support meshes are all coarser than the coarsest filter mesh. Such an arrangement is readily dismantable for cleaning, is resistant to the usual pressures in pipeline flow systems so that filter meshes as fine as 50.mu. do not rupture and permits a high liquid throughput especially when woven plastics filament meshes are employed.