Abstract: The pressure interrupter device provides a simple and easy way to interrupt the pressure in a hydraulic system. A piston having an internal check valve is biased in an internal chamber by a spring. As the piston is moved against the spring by upstream hydraulic pressure, channels in the internal chamber walls are exposed to provide a flow bypass around the piston. The increased flow around the piston reduces the upstream pressure. When the upstream pressure is less than the force exerted by the spring force against the piston and the downstream pressure, the piston moves to a closed position, blocking the channels and stopping the fluid flow. This process is repeated many times at a rapid rate as long as there is a positive pressure upstream of the pressure interrupter device. The piston action operates to create a pulsating effect when the pressure upstream of the pressure interrupter device is greater than the downstream pressure.