A FLOW CONTROL ELEMENT FOR USE AS A FILTER OR GAS DIFFUSER

摘要

A microporous flow control element having a non-labyrinthine, accurately controlled pore size is provided by a helically coiled wire with contacting coils of cross-section reducing inwardly from an outer face so as to define contact edges one of which is provided with microscopic grooves closed by the adjacent coil edge. The wire may be a tension coil spring whereof the coils are held in close contact by the spring force.