Rotary pump on a tanker

[shadowgun1102]

Hi!
What are the advantages and disadvantages of having a rotary pump instead of vacuum pumps on tankers? I found it mentioned on Joskin channel and because I noticed a lot of continental tankers had them.
Thanks!

 

[Mursal]

High output pump will out perform vacuum when filling. Sand and stone get to make contact with the expensive parts using a pump, but can fill the tank to the top. The manufacturers can get away with a lighter wall tank, with the pump.

 

[cosmagedon]

Positive displacement pumps, the tank isn't pressurised so when your running a flow system a 3way valve can return excess to tank.

Higher pressures and flow when working with wider equipment