Tank Sizing

Do you know what a day tank is?

day tank means it supplies contineously fluid to the process or consumer

do u mean it supplies for a day

This and the two adjacent threads are rather vague, and might better have been combined to depict the entire system.

I would consider using a float valve (also called a "trough valve," like a toilet float) to feed the emulsion into the roller tank. There will be some turbulence at the infeed point, but you could put a baffle in the tank so that the infeed is into one compartment while the roller is in a quiescent section. [?] This should give a uniform coating of emulsion onto the roller.

This sounds like a really simple math question, am I missing something here!

Do you know how long the plant production day is so you can multiply this time by your consumption value to estimate the minimum size your day tank needs to be? Take into account same-day production overtime and a reserve capacity safety factor and that should be all you need.

On this basis how should i design storage tank?

If you cannot do the above sizing you really should get someone more qualified to do the design and purchase/build/install for you.