Have you seen a petrol tank vehicle filling petrol at the storage tank or reservoir? If you been pumping petrol all the times but yet to see it, let me show to you now.
First and foremost, the operator need to attach a transfer tube on the storage tank opening.
Next, the operator need to clean the opening of the petrol tank vehicle.
After that, it is the insertion of the connecting tube between the storage tank and the petrol tank vehicle.
Then, adjust on the amount of petrol to be transferred.
Next, insert another transfer tube (green) at another opening on the petrol tank vehicle. This tube is not connected to the storage tank or reservoir but remain unconnected.
After that, wait for the filling of petrol and as part of QC, the operator must record his activities which later be duly stamped by the operator of the petrol station.
Tada... simple right?
And now you understand?
*Pictures taken while waiting friends at Esso petrol station. Captions of the pictures are narrated and not evidence based.