Patent attributes
A backflow prevention device including a tank having a holding chamber and first and second inlets connected with the holding chamber; a control valve having an intake chamber and first and second discharge chambers connected with the first and second inlets, respectively, the intake chamber connected with the first discharge chamber through a valve inlet; a valve sealing element for opening and closing the valve inlet, the second discharge chamber connected with the intake chamber through a hole of the valve sealing element; a float in the holding chamber; a slide bar in the holding chamber, contacting the float, and moveable toward the second inlet under the action of the float; and a slide bar sealing element for controlling opening and closing of the second inlet. When the second inlet is closed, the valve inlet is closed; and when the second inlet is open, the valve inlet is opened.