Centrifugal Pump Performance Curve

I wonder if the OP is referring to a 'rising curve' (a.k.a. drooping head curve):

All the same, someone in a pump company should know about these things.

We can only just begin the guessing game....

Unfortunately the lack of syntax, proper terminology and punctuation will only confuse the issue for the OP.

When nobody tries to state their question or their answers in simple straightforward English we all just waste our time.

I have been a US engineer for over 40 years and I can understand less than half of the questions posed.

I know that some will be deeply offended by this post, however, if we truly want to communicate in English, fundamental skills are required.

Wow! We seem to have some members who are vigorous defenders of the English language who also happen to think suggesting English is neither simple nor straightforward is some sort of slight.

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Very interesting. This does add some weight to the argument that the GA/OT ratings should remain anonymous, because if they weren't I'd be wasting time proofreading for grammar errors in the posts of each negative Nancy.

Let's see.

Gallagher - Messing with your mind - YouTube
Gallagher and English language - YouTube

My dear friend, which 'English' are you talking about?

Sorry, perhaps your 4th paragraph answers that. But if you live in a multi-lingual/multi-cultural region, rather than being totally isolated from the outside world, you get a better understanding of these things.

I dare say the OP has a much better grasp of your language than you do of his (or mine, for that matter), so there might be much you can question about his post, but if I can get his 'English', and you can't, where does the problem lie?

got to agree.... and we don't agree very often!

English while being complex in its simplest form, it would seem that the OP DOES have a far better understanding and grasp than our American friend who wishes to berate the OP for lack of punctuation. 40 years in the USA, and with little world travel has tended to instill intolerance and ergo frustration when ESASL speakers ask a question that is NOT American grammer!

Lets be honest guys. we the British gave you the Americans the Queens English.. look what you did to it.. and then you moan about OTHER English speaker.

ps: ESASL English Spoken As a Second Language.

What?? We fixed the language you "gave" to us.

Two simple examples: colour becomes color here. Why waste letters, and ink. And really, why would anyone in their right mind give a truck a girl's name?

What do they say? Two great nations, separated by a common language.

"Fixed it!" You say you fixed it? Be very careful, Lyn, because I could bore you endlessly on this topic! Furthermore, many of us find Gallagher neither funny nor clever. And this has nothing to do with the US/English dichotomy, it comes from people making fun of things of which they clearly have no understanding. It comes from a very isolationistic 'Us & Them' view borne of those who live very far (and very isolated) from the rest of the world. It also comes from the fact that Gallagher is really rather dull. Believe it or not, there are actually some far better German comedians about! Really!

This sounds interesting. I have to admit I know almost nothing about German prowess in the field of comedy. Would you mind providing some links?

....also, just to be certain, you are aware that Gallagher is not German, right?

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De gustibus non est disputandum.

Sorry, Brich, we probably don't agree on much, and probably never will, despite the fact that I am possibly almost as Welsh as you (Mother's maiden name Jones? Say no more!) . A few facts:

• We did not give America the Queen's English, we gave it the King's English. At the same time we gave it our own systems of weights and measures (eg. Avoirdupois, etc!)
• We Brits like to pretend that our American cousins have 'bastardized' everything we gave them. When you have an understanding of history and linguistics you can see that the 'displaced' people keep things the same, whereas the 'homeland' changes things. The best example of this is modern & ancient Icelandic vs. modern and ancient Danish. Current US pronunciation is broadly similar, in many respects, to what we had in southern England in the early 18^th century, whereas our (UK) pronunciation has changed considerably (also compare 'BBC English' from 70 years ago to current usage).
• We gave them our weights and measures, then promptly changed everything with the 'Weights and Measures Act' of 1824, hence the current difference even with Imperial measures, such as pints.
• Canada does everything better than the US or the UK! Fact!
• What is absolutely the most irritating and dire, on an international level, is the insistence that everyone should speak, do, behave and feel exactly the same as us. The Brits get a bad rap for this (and quite rightly so), but no one comes close to our American cousins. They own this outright!
• If we are open-minded, we tend to find that engineers speak the same language, wherever they are.
• There are many countries where indigenous languages have no history of terminologies in certain technologies, eg. Pretty much all dealings with pumps in the middle east, as you probably know, are done in English. In other countries, it sometimes helps to understand the way they talk, and their own terminologies, to get a better understanding of their English.

I stand corrected.. "King's English"! When I said the Queen's English I am referring to the present monarch, to which it would now be attributed to.. However....

You have added weight (no pun intended) to my argument that, we, the British gave our cousins over the pond a wonderful system, "weights and measures", that was working fine, and apart from minor adjustments, needed no fixing. Falling in line with the EU, decimalization and metrication were the biggest change to our system ever.

But.. they had to fiddle.. it's not broke, but we're gonna fix it anyway!! Same for English!

Perhaps the OP can give the direct wording of the client, not his interpretation of the client's problem.

OP.. I suggest you tell us the whole problem, so we can assist you.

Quickly, yes you can reduce the flow, however you will move to the pump to the left of the performance curve (BEP). But the output pressure will increase if you are just using a flow reducing valve or 'choke'.

I suggest you think about a Variable speed drive, where you can reduce the flow but STILL keep the pump in the curve, therefore reducing any damage you might cause, and maintaining your head psi.

give us your company web site so we can see what you make, also whet type of pump, fluid, surface or submersed, valves and type of motor and motor controller..

I'm not quite following "you can reduce the flow but STILL keep the pump in the curve, ......., and maintaining your head psi." By using a variable speed drive you will reduce head in accordance with the affinity laws by the ratio of the square of the speeds and flow will also be reduced albeit only by the ratio of the speed reduction itself. The curve will shift lower and have the same characteristic curve since that is pretty much based on the physical characteristics of the impeller and casing design.

Changing the Wheel Velocity

My work here is done.

If you are inquiring as to a permanent reduction in head while maintaining the same flows you can remove the impeller and machine the diameter down to meet the new conditions or just buy an additional impeller at the reduced diameter and maintain the old one in case you need to go back to the original condition. Alternately assuming you have a standby pump trim one and leave the other as is. If you're throttling back a lot you could install a bypass to keep the flow above the required minimum.