Pumps in Series Vs. Parallel Graph

[JoeBar]

OMG Martin is on a review frenzy...

[theseeker]

Martin, I read in one your old threads that you recommended 4" tubing run between the pumps. Does this still hold true?

[NaeKuh]

Guess it's time to change my loop around and put pumps in series. Oh well, it's time for a cleaning.

WOW

NECRO'd a thread from 5-2009.

80% of the people posting here do not even date back to that time.

Glad you guys brought this back up. I'll do some actual testing onb this and see how real world compares with some stand alone pumps.

I'll also look at pump redundancy.

You'd have to start from scratch martin. Not unless u can recreate at least one of the old data you had in that bench, which im thinking is going to be very very very difficult.

[Martinm210]

OMG Martin is on a review frenzy...

I get an itch now and then...gotta scratch..

Martin, I read in one your old threads that you recommended 4" tubing run between the pumps. Does this still hold true?

I've never done any testing on this, that was purely based on some rules of thumb I've read about installation of industrial pumps. I've got a water guy in my office that tells me 4XID or four times the pipe diameter is a minimum recommended elbow to pump inlet spacing. This probably depends somewhat on flow rate and turbulence of the stream itself, etc.

But again, never tested it myself, but it has been one of those nagging questions.

WOW

NECRO'd a thread from 5-2009.

80% of the people posting here do not even date back to that time.



You'd have to start from scratch martin. Not unless u can recreate at least one of the old data you had in that bench, which im thinking is going to be very very very difficult.

Are you admitting to being an old timer, you ole fart you!..

Regarding the parallel vs series. The recent Koolance bay res reviews was the first I've done much of any series type testing myself, and it does appear to double pressure head.

To test the theory, I just planning on something like this:

Test PQ

• Single Pump of a PMP450
  
• Two PMP450s in series with a short piece of tubing in between the two
  
• Two PMP450s in parallel using two Y fittings

Compare.

I'm sure there are some minor losses in the interconnecting tubing, but it should be roughly doubling the pressure direction for series and doubling the flow direction for parallel.

It shouldn't be all that hard, all I need is to make myself another copper Y that's very low restriction.

[Church]

You mean Y-s like these or some plastic ones?

[Martinm210]

You mean Y-s like these or some plastic ones?

No, my own custom made type like this:
http://img152.imageshack.us/img152/9...mcoppercc5.jpg

It's a fairly a gradual merge and made of 1/2" ID copper. It's not real pretty, but probably really low on restriction which should help it more closely match theoretical. I still have this one in my parts drawer, just need to make another.

The "mother of all" Y fittings..

[Computurd]

that is a job very well done, looks great
my only question is: will the results using that equipment be truly indicative of that most users get in a typical usage scenario?
also, are the PMP450 going to be tested at variable rates, so that a comparison could be gleaned for low flow pumps such as the PMP400?

[Martinm210]

that is a job very well done, looks great
my only question is: will the results using that equipment be truly indicative of that most users get in a typical usage scenario?
also, are the PMP450 going to be tested at variable rates, so that a comparison could be gleaned for low flow pumps such as the PMP400?

Well, that's debatable I suppose. I just wanted to give parallel the best chance possible since it does have to deal with extra fitting restriction over series. If it looses in the perfect low restriction fitting scenario than it surely would with added restriction.

I'll give it a run, we'll take a look...then see where we to take it from there.

I've got the pump testing bench all set up, so these sort of things are pretty quick to check out..

[Computurd]

i have a parallel setup *of sorts* so this is very interesting to me. one loop is one block for cpu and low restriction rads, but the other has some fairly restrictive blocks, but they all empty into same res.

so i guess the point is, cant wait for your results

[Martinm210]

i have a parallel setup *of sorts* so this is very interesting to me. one loop is one block for cpu and low restriction rads, but the other has some fairly restrictive blocks, but they all empty into same res.

so i guess the point is, cant wait for your results

Ahh...I see. Parallel pumps and parallel loops are sort of two separate things though.

This was talking about parallel pumps (Splitting before two pumps, then merging back together.).

In your case, parallel loops(Splitting after and merging before the pump), that's another topic all together. The trick is as you've mentioned the restriction of each loop. The lower restriction loop might receive 60% of the flow where the high restriction loop would only receive 40%..ect.

Nothing wrong with parallel loops, it's just it's a give and take emphasis of flow rate depending on the restriction of each loop. If you know the other blocks in your setup are higher in restriction, you're probably doing good.

The hard part of parallel loops is the lack of pressure drop info. You could always do a bucket test yourself I suppose, but without some sort of info or quick flow test, it may not be apparent where the emphasis in flow is going. Pretty safe on SLI GPU blocks or dual rads etc though.

In most cases the differences are probably too small to measure, but parallel loops of mixed components should be taken with a bit more planning than single loop series. Series is just hard to mess up, you only have one flow rate to deal with so it's very easy for your average user.

[Computurd]

well i learned something! thx for that now i get it