Orifice-defining entry plate for filtration device

A filter unit for use with a filtrating fluid flow system is configured to receive a flow of a fluid containing particulate matter. The filter unit comprises a filter structure formed of a filter material configured to at least partially filter the particulate matter from the flow of fluid. The filter unit further comprises an entry plate located proximate the filter structure entrance. The filter structure and the entry plate together define a fluid cavity within the filter unit, the entry plate having at least one orifice defined therein through which the flow of fluid can pass into the fluid cavity. The orifice is configured to form a choke, creating a Venturi effect for temporarily increasing the velocity of the flow of fluid through the entry plate and within the fluid cavity, and onto the filter material.