Abstract: A flame arresting filter element for air intake systems has an outer ring of pleated filtering paper and an inner, concentric ring formed of expanded metal foil, longitudinally stretched and laterally compressed so as to be adapted to diffuse and quench frames resulting from engine backfire. The inner ring is coated with a relatively inert, cohesive substance to provide a unitary structure. The two rings are provided with resilient end caps.

Abstract: A feed line for conveying gasoline from the air side of an engine diaphragm fuel pump to the intake manifold consists of a tube having an interior strip with a width equal to that of the inside diameter of the tube wound into a spiral along its length and fixed within the tube. The feed tube allows the return of fuel reaching the air side of the diaphragm of the fuel pump to the engine in the event of rupture of the diaphragm, without the danger of backfire. The introduction of the unatomized fuel into the intake manifold directly or through the wall of the carburetor causes a disruption in smooth engine operation to signal the operator of a disorder.