Fluid vessel with filler pipe

A fluid vessel for an exhaust-gas purification fluid for the treatment of exhaust gas of an internal combustion engine for an aqueous urea solution, the fluid vessel comprising:

• a filler pipe which is connected in fluid-conducting fashion to an interior of the fluid vessel and which, at an end averted from an interior of the fluid vessel, has a filler head;
• a detachable tank cap arranged to close the filler pipe, wherein the fluid vessel and the filler pipe are arranged such that, in an installed position of the fluid vessel, a geodetically highest point of the fluid vessel lies geodetically lower than the filler head, and
• first and second deaeration devices, wherein, the first deaeration device is arranged in the tank cap and the second deaeration device is arranged at the point which is the geodetically highest point of the fluid vessel when the fluid vessel is in the installed position,
• wherein pressure equalization resulting from operation of the first and second deaeration devices to aerate and/or deaerate the interior of the fluid vessel is generated to counteract a negative pressure generated in the vessel interior during extraction of fluid from the fluid vessel.