Fuel tank of thermoplastic material with functional installation fitments for air intake and venting, for fuel take-off and the like

A method for forming a container of thermoplastic material, having an inside wall and a filling volume, and including functional installation fitments, comprising:

• connecting one functional installation fitment to said inside wall of the container by melt-bonding in such a way that the functional installation fitment defines with the container wall a second volume separated from the filling volume of the container in such a way that the inside wall of the container serves directly as a boundary wall of said second volume,
• wherein said melt-bonding of said at least one installation fitment to said inside wall of said container occurs while said container wall is still plastic and during the operation of shaping the tank.