Magneto-active check valve with a reprogrammable cracking pressure

The check valve is essential for controlling flow direction, flow rate, and pressure distribution in a fluidic system. The pressure at which the flap opens in the check valve, called cracking pressure, is fixed because it depends on the material and geometry of the valve. Therefore, reasonable reprogramming of the cracking pressure allows a single check valve to operate in various scenarios and systems. Here, we fabricate a magneto-active check valve using a magneto-active elastomer. The magnetic force applied to the magneto-active check valve was diversified by changing the direction and magnitude of the current along the Maxwell coil. Our experiments on the actuation of a magneto-active check valve under various magnetic forces demonstrate the re-programmability of cracking pressure. We also theoretically analyze the mechanical response of the flap subjected to the gravitational force, magnetic force, and flow pressure. Furthermore, we predict the cracking pressure, defined as the inlet pressure when the contact force becomes zero between the flap and the stopper, by conducting finite element simulations. Experimental, theoretical, and numerical results well-agree with each other, implying that the cracking pressure of check valves can be dynamically controlled within a specific range. Consequently, we expect our new active and passive check valves to be designable for various needs in diverse fields, from drug delivery to gas separation systems.