Level measuring instrument and procedure for its inserting into a container

A process for introducing a filling level measurement device in a tank whose level of filling with a filling medium is to be measured, comprising

• providing a tank with a passage opening leading from outside the tank through the wall of the tank to the inside of the tank, the passage opening comprising an opening wall protruding into the passage toward the inside of the tank, which at least partially tapers toward the inside of the tank,
• introducing a seal into the passage opening of the tank and the filling level measurement device,
• providing a filling level measurement device having a dog fashioned at least in part on the perimeter of the filling level measurement device on the tank side,
• introducing the filling level measurement device into the passage opening from the outside of the tank, the until a portion of the filling level measurement device protrudes through the passage opening wall, leaving a clearance area between the protruding portion of the filling level measurement device and the opening wall, and
• with the dog of the filling level measurement device, pressing the seal in the direction of the inside of the tank, against the opening wall and into the clearance area.