Flow through piping (a highly viscous additive)

[Mudabbir]

Dear Members

Good day to all.
We recently installed a piping system to transfer a highly viscous additive from an ISO tank to another holding tank by using a mono screw/lobe pump.
My question to you all is,the discharge size of the iso tank is 3 inches, will my flow be effected if i change the suction line from 4in to 6in and discharge line from 3in to 5in

 

[gmax137]

"Lobe pumps" are, I believe, positive displacement, right? The flowrate depends only on the pump speed, not the piping sizes.

edit: within reason. if you reduce the pipe size too much you could overpressurize the pump casing

 

[Colin the Engineer]

If the piping is long enough and/or the viscosity is really high then you might see a small increase in flow rate because of a decrease in frictional pressure drop from the increase in diameter and reduction in velocity. But with normal assumptions I would expect to see a negligible change in flow rate.