Best way to have fluid processing time?

I need to run a fluid through a continuous blender that will have a 3 minute retention time. Not a batch time, but a flow through time.
Independent of the amount entering, I need that rate to flow out after 3 minutes.

So, if it starts coming in at 10 GPM and then increases to 20 GPM after a minute, in 3 minutes, it flows out at 10 GPM and then after a minutes starts flowing out at 20 GPM.
The retention time is key, but it is not a batch.

Recommendations?

The fluid conveyor would be able to model this. It is not part of the standard library, but sent a mail to Flexsim if someone can sent you the object.

Regards,
Dirk-Jan Moens