"Jim GM4 DHJ ..." wrote in message
...

just noticed yesterday my car fuel tank has an anti-syphon device fitted
in the neck which won't let you tip the tank up to empty it...... simple
device
or perhaps on further thought is to stop the fuel going the wrong way for
whatever reason ????????????....three hinged triangular flaps which shut
in a frame when you tip the tank upside down....but let fuel through when
filling??????

How do you tip a car fuel tank upside down? That would involve turning the
car upside down. ;-)

Do you perhaps mean a fuel can - a small (eg) 5-litre portable can (plastic
or metal) kept as a reserve or used to transfer fuel to a mower etc.