deciding wether one or two pump is needed

[martino6000]

HALLOW EVERYONE!
I AM CONSTRUCTING A PIPELINE FOR COOLING TOWER .I NEEDED PUMP FOR PUMPING COOLLED WATER BACK TO HEAT EXCHANGER.BASED ON MY PIPELINE DESIGN AND VOLUME FLOW RATE;I HAVE CALCULATED OVERHEAD PRESSURE DROP.I HAVE BEEN SEACHING FOR A SUITABLE PUMP THAT COULD MACTH MY CALCULATED VALUES, I DID GET SOME BUT THEY ARE ALL SPECIFIED TO BE IN USE FOR OTHER PURPOSES e.g IN CHEMICAL INDUSTRIES:IS IT ADVISABLE TO USE THESE PUMPS FOR MY COOLING WATER SYSTEM:HERE ARE MY VALUES.
IS IT BETTER TO USE TWO PUMPS IN PARALLEL CONECTION SO THAT I CAN EASLY GET BETTER PUMP/BEST OPERATING POINT FOR MY SYSTEM.YOUR HELP WILL BE HIGHLY APPRECIATED.
Volume flow:900 cu meter/hr
pump head:98m
Static head:27m
kinetic viscosity:0,68cst
temperature:40°C
PumP power:299KW
Pumpen type:Coolling water pump

 

[Artisi]

"stephenweinstein:

I don't understand your belief that pumps are used to fill vehicle tires. Pumps pump liquids; compressors fill tires. The two handle totally different fluids.

Additionally, please explain your reasoning for asserting that "With 3 x 50%, you are more likely to have two simulatenously out of service". Is this your belief or someone's theorem or finding? While this could be true, what is the engineering logic behind it? The same comment applies to your statement: "With 2 x 50%, you are more likely to have everything simulataneously out of service".

I have operated cooling towers with 2 x 50% capacity pumps in many sites and never had any failures - much less everything simultaneously out of service. Perhaps I'm just lucky, but I'm willing to learn about this probability."

I too was a litle puzzled by this posting, but getting back to 2 x50% versus 3x50%, it all comes down to economics, and your faith in the installed equipment etc.
2x50% units is fine as it always gives at least 50% capacity should one unit ever go-down or has to be shut for unscheduled maintenace, however 3x50% will (usually) give 100% capacity even allowing for the failure of 1 unit or unscheduled maintenance on 1 unit, it also give you the benefit of having one unit out of service for routine maintenance.



Naresuan University
Phitsanulok
Thailand

 

[Artisi]

This thread seems to be very typical of a lot of threads started in this forum. Somebody poses an interesting question or problem and many of us have fun bantering back and forth our ideas and theories - unfortunateley in many cases the original poster just seems to vanish into thin air never to be heard from again.
I for one always feel that it would be nice to hear that our collective help overcame a problem - but guess that's in a perfect world, anyway, maybe we have helped someone else along the way to make it all worthwhile.

Naresuan University
Phitsanulok
Thailand