Originally Posted by

**adosana** Thank you HallsofIvy,

The amount op pollution is in m3/min at constant rate that comes into the oven. The requirement is that amount of pollution doesn't exceed a certain vol% inside the oven. So if you know what volume of polution is as function of time than you can easly calculate %vol of pollution relative to the total volume of the oven which is constant. Then %vol of pollution = V(polution)/V(oven)*100%

So I am looking for differential equation that discribes V(pollution) in the oven as function of time. Note: not only pollution is flushed out, also the air in the oven is being flushed out.

At t=0 you have 100% air in the oven. Then for example at t=1 min you have V(pollution) in m3 and V(air) in m3. Both amounts are being flushed at flush rate Vf [m3/min). I expect that at certain time the same amount of pollution is flushed out as it comes into the oven (equilibrium). Does your equation describe this situation? What is the outcome of your equation if you differentiate dt? In your equation V means oven volume?