Sometimes called a "solenoid valve;" a valve installed at the highest point in the piping to prevent liquid from accidentally siphoning or leaking out of the tank in the event of a piping leak or rupture. An anti-siphon valve is needed when the liquid level in the tank is higher than the elevation of the dispenser or any product piping (which is usually the case at marina fueling facilities).
A device that prevents waste water from being drawn back into supply lines and possibly contaminating the water supply.
Preventive device for back-flow of liquid such as on sprinkler systems to prevent water from trickling back into the feed supply.
Preventive device for the back-flow of liquid into a system. Used in sprinkler systems to prevent water from trickling back into the water supply that is feeding it originally.