US Patent 7527069 Electromagnetic split flapper pressure relief valve

A pressure relief check valve system includes a valve body, a flapper, a magnet, an electromagnet, and a pressure sensor circuit. The flapper is rotationally mounted on the valve body and is movable between a closed position and an open position. The magnet is coupled to the flapper, and the electromagnet is coupled to the valve body. The pressure sensor circuit is adapted to sense one or more fluid pressures and is operable, based on the one or more sensed fluid pressures, to selectively supply or interrupt the electrical current to the electromagnet. The electromagnet is coupled to receive the electrical current and, upon receipt of the electrical current, either magnetically attracts or does not magnetically attract the magnet, to thereby hold the flapper in the closed position or allow flapper rotation to the open position, respectively.