Determination of the degree of blockage of a liquid or gas filter, by progressively exposing more of the filter surface as the upstream pressure increases

摘要

A dividing disc (6) forms a seal between the filter unit (6) and outer casing (2). As the filter becomes blocked increased pressure on the upstream side pushes the divider downwards, exposing more filter surface. The outer casing is transparent, or has a window or some other device, so the position of the divider can be determined.