Abstract: Safety valving for cargo tanks used for bulk transportation of hazardous commodities, such as for instance flammables. The valving provides automatic differential pressure relief for the tank, and overturn protection, with the automatic differential pressure relief including port means in the housing for the valving, adapted for communicating the interior of the associated tank with the exterior atmosphere, and comprising poppet type closure means coacting with the port means and biased to normally closed condition, but being openable to provide automatic differential pressure relief. The overturn protection section comprises an angle responsive closure means responsive to predetermined angular orientation of the valving relative to the vertical, and operative to close the associated port means of the valving against inadvertent escape of the tank's contents, when the tank is at least in partially overturned position.

Abstract: A discharge control for a storage tank for liquid, such as a gasoline transport tank, with the tank having an outlet port with the control comprising an emergency valve associated with the port, with such emergency valve normally being biased to a closed position, whereby discharge from the tank is prevented. Enclosed or protected valve operating means coacts with the emergency valve and is responsive to air pressure, for overcoming the normal valve closing bias of the emergency valve, wth the valve operating means including a crank comprising an operating lever with a crank case in which the lever is disposed, and with an air operated reciprocal motor unit secured to the crank case for coaction with the lever of the crank upon application of pressurized air to the motor unit, to cause the crank to move the emergency valve to open position. The valve operating means is able to be operated manually in the event of failure of the pressurized air supply.