Fuel contamination monitor having a shut-off valve

Claim 1

A fluid filtering unit comprising: a housing having fluid pervious walls for the entrance therethrough of a fluid, and an outlet port for the exit therefrom of the fluid; a tubular filtering element disposed within the housing permitting fluid flow therethrough from the outside to the inside of the tubular filtering element, said tubular filtering element being in a alignment with said outlet port; means placing said tubular filtering element under a predetermined axial compression; valve means disposed at the other end of said tubular filtering element normally closing that end of said tubular filtering element to the passage of fluid, said valve means having one side exposed to fluid pressure inside said tubular filtering element and the other side exposed to fluid pressure outside of said housing so that when a predetermined pressure drop occurs across said valve means, said valve means concurrently opens the end of the tubular filtering element at which it is disposed and closes said outlet port thereby preventing further fluid flow through the filtering unit and, a layer of filtering media disposed within said housing in confronting relationship to said fluid pervious housing wall for separating submicronic particulate matter from the fluid as it passes through said fluid pervious housing wall, said filtering media and said tubular filtering element being in series fluid communication, such that, when a fluid enters said housing through said fluid pervious walls and said filtering media, said fluid next passes through said filtering tubular element toward said outlet, said fluid communication through said outlet being terminated when the pressure drop across either said tubular filtering element and/or said particulate filtering media is above a predetermined level.