PARALELL PUMPS 2

[gorkus]

HELLO, COULD YOU help me with this case:

flow = 500.000 l/h
Suction= on load
Discharge= 2000 mts length,10 mts high. diameter 10"
liquid= vegetal oil ( 500 ssu)
these rules are ok?

Qt= Q1+Q2+Q3+Q4
Ht= H1+H2+H3+H4

so..
I HAVE TO SET 4 VANE PUMPS IN PARALELL.
EACH OF THEM IS GOING TO DELIVER 125.000 L/H.


PUMPS DELIVER THE LIQUID TO A 10" COLECTOR THAT GO 2000 Mts STRAIGHT TO THE SHIP.

DISCHARGE HEAD VALUE IS 11.5 BAR. ( aprox)

EACH PUMP HAVE TO DELIVER 125000 L/H,AT 11.5 BAR PRESSURE AT WORKING CONDITIONS.
is it true.??

Then I have to know how is the power that each pump needs to pump the liquid to the ship.
flow= 125000 l/H
discharge head= 11.5 bar

 

[nickelkid]

Please review

http://www.mcnallyinstitute.com/18-html/18-1.htm

 

[BigInch]

Ht DOES NOT = h1 + h2 + h3 + h4

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic
"Note: Make that 99.99% for pipeline companies" -

http://virtualpipeline.spaces.live.com/

 

[gorkus]

sorry

THE HEAD IS:

ht=h1=h2=H3

tHIS IS CORRECT??

 

[BigInch]

guess again

parallel heads do not add together. Head will be somewhere inside a range from the suction head + lowest pump differential head to the suction head + highest pump differential head.

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic
"Note: Make that 99.99% for pipeline companies" -

http://virtualpipeline.spaces.live.com/

 

[gorkus]

so how can I get the woking pressure for each pump.??

First I calculate the total head value ( of the piping system) and then with this value I go to the curve and I get the power required for each pump.( with its flow, the same each pump)
I thougt that the prssure value was The total head value of the piping system for each pump.

Do you understand me??

 

[bk19702]

Please review (worth repeating):

 

[BigInch]

pressure = maximum required head x specific gravity of fluid x reference density of water

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic
"Note: Make that 99.99% for pipeline companies" -

http://virtualpipeline.spaces.live.com/

 

[Artisi]

Head is the vertical distance from inlet level to the highest point in the discharge line PLUS all friction losses which must include losses thru valves, bends etc. based on the friction factor for vegetable oil thru a 10" pipeline and corrected for specific gravity.

For instance, if the total discharge head is - let's say 10 metres for the discussion, then each pump sees the same discharge head (10 metres) while pumping at the specified rate with the 4 pumps in operation.

 

[Artisi]

" **********************
"Pumping systems account for nearly 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic"

Of the 20% of the energy used, what percentage of that do you think is wasted energy due to poorly selected pumps, pipelines, configurations etc resulting in operating away from BEP, by-passing excess flow back to source, throttlled flow etc?

 

[nickelkid]

Artisi,

I need to stop thinking about all of the poorly sized systems I have observed in the US and abroad. With that said, I will guess a minimum of 25% is "wasted energy"

 

[BigInch]

Taking into account energy wasted by the missuse of "energy savings devices", those flow controlled systems that would be better served with a tank and an on-off switch, one size too small pipe diameters, reduced motor efficiency from running at partial loads, too small or too long electrical cables, water pumped but leaked from piping or otherwise wasted by the end user, it will even be higher.

33.33 -50 % ?

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic
"Note: Make that 99.99% for pipeline companies" -

http://virtualpipeline.spaces.live.com/

 

[Artisi]

Difficult to put a number on it - but from what I've seen over the years I wouldn't be surprised if wasted energy exceeds well above 50% - now that's a lot of power wastage across the whole world.

 

[BigInch]

Opps. Could be higher than we both thought.
See thread407-231185

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[BillBirch]

gorkus,
Do you really mean vane pumps? These are positive displacement pumps, but your discharge head is quite high for this type of pump. Can you provide details of the pumps?

 

[Artisi]

At this stage I believe head is unknown - it is assumed the OP summed the individual pump head to arrive at the 11.5bar as per the first posting and we haven't heard any different at this stage.