Oil pressure delay check valve and pressure switch for shutting off

Abstract

Oil pressure delay check valve and pressure switch for unattended Diesel engine to shut off the fuel supply valve after a low oil pressure signal, and to delay opening of the valve for a predetermined time interval. This delay is attained by the closing of a normally open pressure switch upon pressures decreasing from the order of 8 psi and by bleeding the oil pressure past a check valve through a bleeder tube in cooperation with an accumulator, from a pressure in the order of 8 psi to a pressure in the order of 5 psi to accommodate the opening of a normally closed switch as the pressure decrease from the order of 5 psi. The two switches are in series and when closed, energize the solenoid of an electrically energizable valve to shut off the supply of fuel to the Diesel engine. As the oil pressure decreases, one pressure switch will close and remain closed while the other pressure switch will open in a predetermined time delay interval and effect opening of the fuel supply valve. The delay check valve connected with the oil pressure manifold of the engine is spring-biased into a closed position and has the bleeder tube leading therethrough affording communication between the valve inlet and the valve chamber. The normally closed pressure switch in series with the main oil supply pressure switch is connected with the valve chamber and receives pressure therefrom. An accumulator connected with the valve chamber accumulates oil under pressure and when the oil pressure reaches 8 psi or more, the normally open switch will close, and when the oil pressure in the valve chamber drops below 8 psi, the trapped oil pressure will bleed down through the bleeder tube to 5 psi, and accommodate opening of the fuel supply valve and the establishment of the supply of fuel to the engine.