The no. 72 series Auto-Vents are reliable, automatic air eliminating valves for concealed radiators, pipe lines, tanks and other devices where water or liquids are used for heating and cooling. They have proven to be the solution to problems that have confronted engineers and contractors in which air pockets or traps retard the free circulation of the liquids and reduce the efficiency of the system or appliance. The no. 7 series Auto-Vents air eliminators are made of brass and equipped with a self-closing, float-operated valve. The valve is equipped with a Monel metal spring and a Neoprene valve seat which is unaffected by high temperatures, oil and anti-freeze. No air chamber is required. The vent is regularly fitted with a patented cap that may be used as a check in case of a leak caused by core sand or scale.