Pressure through a Pipeline

[buddabeast]

Hi guys, I have a question about water pressure through a 1.5" PVC pipeline.

The supply pressure is around 700kPa (from a reservior on a hill). The water line runs about 10m to a pressure regulator which is currently set to 200kPa. This water is then used to power a venturi to suck up powdered carbon. The doseline then runs about 30 m with 12 bends and rises about 6 m high. (maybe 400kPa friction and lift pressure here?)

My supervisor is telling me the doseline needs replacing as there is too much backpressure on the venturi - however I don't think so.
I can increase the pressure to around 500kPa with the PRV and decrease it right down also.

But I don't know how to explain to him that the doseline is OK..

Thanks for any help.
Heath

 

[bimr]

What you have described is a sluicing eductor.

Sluicing Eductor

The operating results will be difficult to predict because of the materials that you are handling. You may have material clumping, bridging, different volumes of sluicing water, effects due to shape of hopper, etc.

Performance chart is listed here:

Performance Chart

Here is a picture of an eductor that was used on a recent project. These eductors are used to sluice media in order to load water treatment vessels with media. This eductor includes a pump to add water pressure.

Suggest that you optimize the operation and then demonstrate it to your boss. Don't believe that there are any simple calculations for this. The best calculation that you may develop will just be an operating range.

 

[georgeverghese]

You might want to consider a check valve that provides more open cross sectional area than a ball check for unimpeded flow in this case since there are entrained solids to accomodate - like a dual plate or a tilting disk check valve.