Flowrates in gravity system + piston pump

[dutchbomb]

Hi all

I hope you can help me here. I am trying to model an elevated vat which is using gravity to supply water to a filler. The pipeline has filters and bends in it which lead to headlosses. The filler supplys a fixed volume of liquid to a bottle at set time intervals. The filler is basically a glass jar (of sorts) with a piston in it and every time it needs to fill a bottle the psiton moves up - thereby pulling water into it. Once it has been filled the inlet valve shuts, oulet valve opens and the piston moves down - thereby filling the bottle.

I previously calculated the flowrate of a simillar system assuming it was one vat draining into the other. Here i wrote all sources of headlosses in terms of Q, summed and equated these to the total available head and solved for Q. This was a straightforward method which provided me with good results.

However, with the inclusion of the filler and the suction head it provides at intervals I'm not sure how to calculate the flowrates. Essentially i am looking to see if there is enough head available to supply the filler with enough water.

Your thoughts are appreciated!

 

[Navin A S]

</code>One possible approach is to calculate the headlosses for each component in the system, then deduct these from the total available head. For example, if the total available head is 10m, and you have calculated that the filters and bends cause a total headloss of 2m, then this leaves 8m of head available for the filler. You can then calculate the flowrate required to fill the bottle in a set time interval (e.g. 60 seconds) by dividing the volume of the bottle by the time interval. This should give you an idea of how much water needs to be supplied to the filler in order for it to fill the bottle in the given time. You can then compare this with the available head of 8m to see if there is enough pressure to supply the required flowrate. If not, then you may need to consider other solutions such as increasing the total available head, or changing the configuration of the system to reduce the headlosses.