No weak points
A cylindrical-shaped container doesn’t have structural weak points that require reinforcing. In fact, a rectangular or a square shaped container has corners and flat sides that can easily break under high pressure. It means conventional rectangular container will lead to failure over time quicker than a cylindrical container.
When a tanker accelerates or de-accelerates, the liquid in the tank sloshes around due to the law of inertia i.e., “a body at rest remains at rest and a body in motion continues to move until an opposite external force acts on it”. The phenomenon of sloshing is called as ‘surge’. To reduce the surge effect while slowing down or accelerating during the travel, the tankers have metal sheets placed inside them that reduce the to-and-fro surging of liquid. That’s why experienced drivers maintain a habit of slowing down or accelerating their tanker trucks smoothly.
Moreover, a spherical container counters the surging of liquid better as compared to other shapes.
Extraction of liquid
A cylindrical container is most favorable in extracting the liquid from the truck in an easier way than the other shaped containers. This is because the liquid gets funneled down to bottom of a cylindrical tank and even the least of drops flow out. On the other hand, a rectangular tank would not allow the movement of liquid at the vent point and all the time some amount of product will always be left behind.
A cylindrical container is easier to clean than any rectangular container because in a box-shaped tank the traces of liquid will get stuck at the corners and eventually be harder to remove. A cylindrical container contains no such corners, therefore their cleaning is easy.