A valve structure of a fluid delivery and analysis system having an upper substrate, a lower substrate and an intermediate layer with at least one opening and at least one open cavity having a first touch point between the upper substrate and the intermediate layer and a second touch point between the lower substrate and the intermediate layer where the first touch point and the second touch point are offset to create a torque so that when intermediate layer is compressed between the upper substrate and the lower substrate that the torque deforms the intermediate rubber layer in the direction of the opening for better sealing.