container is a delivery pump for emptying it into the delivery volume of the fuel tank application_number US 51230309 A description the fuel tank 1 shown in fig1 includes in known manner a filler pipe 2 and means not shown for conveying and removing fuel for delivery thereof as well as means for introducing air into and venting the fuel tank 1 during refuelling and operation in general the fuel tank 1 is for example in the form of a plastic tank which was produced in one piece by extrusion blow molding it can be of a comparatively complicated chamber like structure involving various sub volumes the fuel tank 1 shown in fig1 is illustrated in a greatly simplified form for the purposes of enhanced clarity for the purposes of venting the fuel tank in a refuelling operation or in operation provided in the fuel tank are various ventilation points which can each be controlled with respective valves from the valves venting lines 3 are taken by way of a collecting container 4 to a fuel vapor filter activated carbon filter not shown for that purpose the collecting container 4 shown in the figures is connected to an operational venting line identified by reference 3 b and a refuelling venting line identified by reference 3 a reference 5 denotes the pressure compensating line which is passed.