Abstract: A fuel vapor storage canister having a screen assembly between a mass of carbon granules in the storage canister and a purge port of the storage canister. The fuel vapor storage canister includes a cup-shaped plastic body defining a carbon bed chamber and a plenum in the canister body covered by the screen assembly. The screen assembly includes a pair of concentric cylindrical bosses around the plenum, a plastic foam screen over the plenum seated on a circular edge of each of the concentric cylindrical bosses, and a retainer having a plurality of flexible barbs and flexible reinforcements resiliently biased against opposite sides of the outermost one of the cylindrical bosses. Concentric circular segments of the plastic foam screen are compressed tightly between an annular planar side of the retainer and each of the circular edges of the concentric cylindrical bosses to positively prevent migration of carbon granules around the foam screen.

Abstract: A fuel vapor storage canister having a screen module between carbon granules in the canister and a purge port of the canister. The screen module includes a module body defining a plenum, a flat plastic foam screen seated on an uninterrupted edge of a raised boss on the module body around the plenum, and a retainer clamped to the module body over the flat foam screen. A tubular stem on the module body plugs into a socket in the storage canister. An interference fit between the tubular stem and the socket prevents migration of carbon granules between the socket and the tubular stem. The foam screen is exposed to the carbon bed chamber through a window in a planar side of the retainer which planar side, in a seated position of the retainer on the module body, cooperates with the uninterrupted edge of the raised boss in compressing a segment of the foam screen to define a seal around the window.