Filter bypass indicator

The combination comprising housing means having terminal means associated therewith and a filter element, and bypass means associated with said housing means and comprising a piston movable in first and second directions relative to said housing means within a bore defined by the housing means, and resilient means for resiliently urging the piston in the first direction, said piston being movable in said second direction against the resilience of the resilient means, the piston being movable in said first direction to a position directing fluid through said filter element, and movable in said second direction upon buildup of fluid pressure thereon due to blocking of fluid flow in the filter element, against the resilience of the resilient means, to a position wherein the fluid flow may bypass the filter element, and means for maintaining an electrically conductive state between the piston and the terminal means upon an initial degree of movement of the piston in its second direction against the resilience of the resilient means due to a degree of fluid pressure buildup on said piston, and for breaking said electrically conductive state between said piston and said terminal means upon further movement of the piston in the second direction, due to further fluid pressure buildup on said piston.