Patent ID: 8517105

Claim:
A variable flow resistance device defining at least one flow path, the flow path comprising: an inlet and an outlet; a vortex chamber; wherein the vortex chamber has first and second inlet openings each fluidly connected to the inlet of the flow path and first and second feedback outlets, wherein the first and second inlet openings of the vortex chamber are positioned to direct fluid in opposite, tangential paths into the vortex chamber so that fluid entering the first input inlet opening produces a clockwise vortex and fluid entering the second inlet opening produces a counterclockwise vortex, and wherein the first and second feedback outlets of the vortex chamber are positioned to direct fluid in opposite, tangential paths out of the vortex chamber, whereby fluid in a clockwise vortex will tend to exit through the second feedback outlet and fluid in a counterclockwise vortex will tend to exit through the first feedback outlet, wherein the first inlet opening is adjacent the first feedback outlet and the second inlet opening is adjacent the second feedback outlet, and wherein the first and second inlet openings and the first and second feedback outlets are all within about a 180 degree segment of the periphery of the vortex chamber; a switch for changing the direction of the vortical flow in the vortex chamber; a feedback control circuit for operating the switch, wherein the feedback control circuit is controlled by fluid output from the vortex chamber through the first and second feedback outlets; wherein the vortex chamber has a vortex outlet fluidly connected to the outlet of the flow path; and wherein the device comprises a structure split into two halves with opposing internal faces, and wherein the flow path is defined in at least one of the opposing internal faces.