additional pvc piping for water supply
additional pvc piping for water supply
(OP)
hello everyone, i need some help from our expert members. we have an existing 8" dia. PVC water line with a water flow of 40 liters per second which is being directed into two 6" dia. PVC pipes. now, we are planning to fix a new 6" dia. PVC pipe into the 8" dia. (its water flow is 30 liters per second). My questions, will there be any problem in case this will push thru? Can the 2 six inches diameter PVC pipes accomodate the new 70 lps water flow or discharge and how about the original 8" dia. pipe? By the way I'm working for a local water distribution company here in the Philippines.





RE: additional pvc piping for water supply
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: additional pvc piping for water supply
As BigInch stated, we need more input.
RE: additional pvc piping for water supply
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: additional pvc piping for water supply
before connecting the 6" 30 lps PVC pipe, the velocity of water on the 8" dia. is 1.32 m/s and the velocities on the 2 pcs assuming they are halving the original flow rate is 1.31 m/s.
for the second situation, after connecting the new pipe (velocity on this 6" pipe with 30 lps flow rate is 1.96 m/s) on the 8" dia PVC pipe the velocity will become 2.31 m/s on that pipe (8" pipe). and the velocities on on the two 6" pipes will be 2.29 m/s assuming they will halve the 70 lps flow rate.
Is the continuity equation applicable on this?
Does anyone here have an idea also regarding Recommended Velocities for fluids in PVC pipes? Is 2.5 m/s the maximum allowable velocity in PVC pipes?
Many thanks to everyone for the help and enlightenment.
Mabuhay!
RE: additional pvc piping for water supply
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: additional pvc piping for water supply
i'm just new in this area of Mechanical Engineering that's why pardon me for so many questions.
Another question sir, which would you prefer between these options:
1. to make a parallel transmission mains of a 6" dia. with 30 lps and 8" dia. with 40 lps and then make a loop at the distribution line,
2. to connect the 6" dia. pipe to the 8" dia. pipe ( this was the question that's i've been asking if it'll cause some problems on the 8" dia. pipe)but it'll have 2 6" dia. pipe again at the end of the 8" dia. pipe 1 kilometer from the point of interconnection.
many thanks...
RE: additional pvc piping for water supply
If I understand your system configuration...
And assuming you want to go for minimum cost,
First I would look at a design without looping the 8" with the 6", as long as surge pressures would not become significant, then change to 2-6" lines at 1 km. You must be sure you have pumps with combined characteristics operating in parallel (I think that is the case, right?) that will be able to make that flow against the new pipe H-Q curve and still be within the pressure capacity of your PVC.
If surge was a problem with high velocity in the 8" line, then I would try looping the 8" with 1-6" changing to 2-6" lines at 1 km and, just to be sure, check the surge pressures again with that configuration.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: additional pvc piping for water supply
hope i was able to explain the situation clearly sir BigInch.
RE: additional pvc piping for water supply
Without knowing the details of the elevations and pumps etc, still no way for me to say what would be best. It looks like a single 8" line might work, in lieu of making the loop now, but I can't tell you that from here with any degree of assurance. If you're still not sure what to do, I suppose you could always connect the 6" to the 8" and if it didn't work well, install the 6" loop at some point in the future.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: additional pvc piping for water supply
taking into consideration the pressure surge that might occur in case i'll connect the new 6" dia. (30 lps or probably more) into the 8" dia pipe (which carries 40 lps already). i think it's better not to connect the 6" into the 8" pipe which will result into a 70 lps flow into the 8" dia. pipe.
more power to you sir!
RE: additional pvc piping for water supply
Good luck.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com