A flat pump for producing liquid spray or for producing an atomized liquid stream may have a thickness of 6 millimeters or less. The flat pump may include an internal reservoir (3), a valve (19), a valve conduit (45) and a vortex chamber (49) wherein fluid from the reservoir may be pumped through the valve, along the valve conduit, and into the vortex chamber. An atomized liquid stream, spray, or mist formed in the vortex chamber may be expelled from the flat pump.