Wondering in anyone has ever set up an air purge system on fertilizer/water/ transfer pump nurse wagons ?

I've seen a setup like this on fuel trucks to eliminate slopping,spills and for draining fill hoses.

Are there special fittings required or what exactly is needed to make this work. Is this using compressed air from the air brake system or is some sort of vacuum needed instead ?

I've got an old large Oxygen cylinder that was gave to me from an old timer who has since passed away. Oxygen place will not fill or accept this bottle with out a signed affidavit that I was given the bottle so I'm out of luck there.

I thought it would make a more than stout reservoir for air pumped up to say 150psi and would give lots of capacity for purging lines.

It would also be nice to be able to connect and disconnect from planter and applicator or refill nurse tank without that little splash when disconnecting hoses. I can usually do okay filling the planter by closing valve on nurse tank then at planter then at the hose end then shutting off engine and pump. It creates enough suction in the fill line when the pump stops that when you disconnect from planter and crack valve before breaking the seal it will suction out the area between the valve on the planter and the valve on  the end of the hose.

Just considering ideas to make transferring liquids less sloppy. I also intend to set up the valve sequence so that I can use the nurse tank mounted pump to pull out of the supply tank or to also use it to pump out the planter when finished.