pump graphs... here is a silly question!
pump graphs... here is a silly question!
(OP)
hello, ive just started a new job 2 weeks ago and have been given a small project but where is the question...
if the pump is rated to 410m3/s at 35m @ 1750rpm
and ive got the pump curve
why whould this nember not be shown in the chart? this point is about 10% too low on the graph, if 410m3/s is fed in to the graph i get 40m
cheers
Sean
if the pump is rated to 410m3/s at 35m @ 1750rpm
and ive got the pump curve
why whould this nember not be shown in the chart? this point is about 10% too low on the graph, if 410m3/s is fed in to the graph i get 40m
cheers
Sean





RE: pump graphs... here is a silly question!
Regardless, you should develop a system curve and plot it against the pump curve. Where the two intersect will be your operating point.
Cheers,
CanuckMiner
RE: pump graphs... here is a silly question!
Things to check:
-Impeller diameter same as shown on curve?
-Was a performance test done on this pump? If so, you
should have a specific curve for the pump instead of a
generic one. (will have serial number, impeller trim,
date, etc. shown on chart)
-If pump is installed, the dead head pressure (pressure developed with no flow) can usually be checked to confirm whether it is operating on or below the curve.
RE: pump graphs... here is a silly question!
1 - Is the speed on the curve shown as 1750?
2 - The mention above that rated is usually less the curve makes me wonder if the manufacturer might build in a little margin. The curve might be like a best estimate new and the rated sort of like a minimum value? I don't know but just wondering aloud.
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RE: pump graphs... here is a silly question!
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Eng-tips forums: The best place on the web for engineering discussions.
RE: pump graphs... here is a silly question!
RE: pump graphs... here is a silly question!
rmw
RE: pump graphs... here is a silly question!
on the contrary, if the pump @ 410 m3/h developed only 30m then it is too small for the service.
what happens is that the diameter of the impeller must be machined to give exactly the head you need or...
draw the curve of the system and see what is the actual operation point.
saludos.
a.
RE: pump graphs... here is a silly question!
going to have a proper look at it on monday!
I'm not very experianced with pumps and the accociated diagrams. Yeah its shown as 1800RPM in the curve but i made an allowance for this.
pump specs(off the top of my head):
1750 Rpm,
75KW,
77% hydraulic efficiency,
114 L/S,
3 phase,
460V,
1900kg dry with skid,
it is used for hanging off the side of an oil rig to supply another booster pump on the deck... check some of the pics out thay are quite cool!
http://www.rigcooling.com
thats about all i can remember at the moment... had a bit of a heavy night yesterday so not feeling my best!
RE: pump graphs... here is a silly question!
RE: pump graphs... here is a silly question!
1) Are you pumping anything else but (sweet) water at 60 deg F?
2) Are the impellars the same as for the curve
3) Since you speed is slower than the design speed you would expect a lower head - but you find a higher. Have you gotten it backwards in you compensating? (or am i misunderstanding you)?
Best regards
Morten
RE: pump graphs... here is a silly question!
Yeah ive read most of that site, its just this bloody curves are not correct!
as for the Questions:
No,
Yes,
Yes ive assumes a slightly lower head, its still about out 10% out...
going to call the makers and have a convo with the person there! There might be a good reason for it!
RE: pump graphs... here is a silly question!
Naresuan University
Phitsanulok
Thailand
RE: pump graphs... here is a silly question!
it will be interesting to see how he has calculated the supplied results... i'll keep you informed.