Common pump P-Q Curves (graph inside)

[Skulemate]

Wow... compared to those other pumps, the MCP600 looks like quite the solid performer.

[pHaestus]

Some (preliminary) testing here:

http://forums.procooling.com/vbb/sho...5&pagenumber=2

Yea it's a very nice pump.

[Groth]

Found an interesting link: http://www.reefs.org/library/pumps/

Let's see pHaestus put all those on one graph!

[pHaestus]

(1) I'd need more than those 2 numbers to do so
(2) I'm working on dynamic graph generation (well Joe is) that'll let you pick any pumps or wb test results or whatever and graph them vs. other test results. As soon as he sobers up I'm sure he'll get right on that

[BillA]

many of the curves are shown in the "more info" links
I submitted the MCP600
lol

[pHaestus]

Good lord that's beautiful!

[Cathar]

Posted this at OCAU.




Some notes:

*) This post was designed for an Australian audience. Ignore the prices listed unless you want a good laugh about how much us Aussies get ripped off on pump pricing.

*) The Danner Mag 3 line is my personal interpretation of a best fit line given the data presented at their website. Their data produces a line that is not even remotely smooth, so I look the liberty to smooth it out somewhat. If anything, I may have overestimated slightly. The in-line heat figure is another approximation drawn from reading about people's experiences. I believe it to be somewhat close.

*) The Swiftech MCP600 in-line heat is another approximation, based on motive pumping power which must be ultimately converted as frictional heat into the water, and some heat from the motor itself.

*) The Johnson pump may be obtained for the price stated from www.depcopump.com. The in-line heat value is an approximation based on my experiences with the Davies-Craig EBP, with both pumps sharings a similar design.

*) The Davies-Craig EBP price quoted is an over-the-counter cash price direct from Davies-Craig. The on-line order price is $201 AUD. (http://www.daviescraig.com.au/newproduct_ebp.asp)

*) The Eheim pumps voltages/frequency is not given as Eheim release correctly spec'ed models for whatever country they are targetted for. This means that so long as you buy the Eheim pump that is correct for your country, you should see the performance stated. The Eheim PQ curves on the literature did not have uniformally placed graph lines. The PQ curves given are based on an interpretation of the graphs using the global min-max scale of the graphs presented, and then following the points on the curve. I believe that this actually eliminates some of the discrepencies with the visual interpretation of the Eheim PQ curves that people have occasionally reported on.

*) The block flow/pressure resistance curves presented are for the blocks themselves only. They do not include additional resistances that may be introduced by a radiator or other heat-transfer device.

[Blackeagle]

That chart of pumps is impressive indeed.

Links to that can be about as helpfull as the heater core data base been for those seeking a good rad. This link will set up those seeking a good pump.

Very impressive.

Cathar, nice graph for the WW & Cascade. But why no curve for the Iwaki MD20rlzt?

[Cathar]

Originally Posted by Blackeagle

why no curve for the Iwaki MD20rlzt?

LOL - You're the second person to ask for it. I presume you want the 115VAC/50Hz curve for the MD20-RZ?

[Cathar]

Okay, re-edited the graph with some assistance for the color-blind (had some complaints about it), and added the 115VAC/50Hz MD20-RZ.

The new graph replaces the old at the site, so if you can't see the updated information then press <shift>+<F5> to refresh it.

[satanicoo]

From what i see the cascade is more resistive than the white water?
And in this case a 1250 equals a mcp600 for the white water.

Could you put there a cascade + heatercore flow vs pressure grafh?

It would represent a more realistic situation, the mcp would look way better, and the iwaky md20 yummy

[Cathar]

Originally Posted by satanicoo

From what i see the cascade is more resistive than the white water?
And in this case a 1250 equals a mcp600 for the white water.

Could you put there a cascade + heatercore flow vs pressure grafh?

It would represent a more realistic situation, the mcp would look way better, and the iwaky md20 yummy

Yes, Cascade is more restrictive than the White Water. Only the first rev Cascade prototypes were less restrictive. As you can see though, despite being about 50% more restrictive, it typically makes for just a 5-15% difference in volumetric flow rates due to the shape of the curves.

What heater-core?

I use the Camry cores ("Big Arse"). Flow rates with the core attached are typically 5% less than where block lines intersect the pump lines for most scenarios when the math is worked out. The Camry cores have about a 0.7mH2O PD at 10LPM with the 1/2" copper-tube fittings I use.

[satanicoo]

Thats a 2*120mm fan heatercore right?

Was reading the graphs bad. i guess the diference inst that much.

[agiacobbi]

Can someone explain what the 5 or 6 feet of head is. Is that the pressure or length of distence the pump reaches or maintains the GPH. How the hell does that work. Been reserching and reading for about a year now and I have yet to hear it explained. Probably a n00b question.

[bigben2k]

Yes, a noob Q, but that's ok.

It's confusing because many different terms are used by various manufacturers. The short answer is that it's the maximum pressure that the pump can deliver.

The long answer is...

It's sometimes called "dead head", because it's the pressure level at which the flow rate becomes zero.

It's also called "head" or "max head", as this max pressure is often expressed as the maximum height of a water column that a pump can sustain.


If you look at any of the PQ graphs above, you'll see a maximum flow rate, and a maximum pressure. Obviously, once you hit the max flow, there's no pressure, and when you hit max pressure, there's no flow...

[bobkoure]

Originally Posted by pHaestus

...Bill has some pretty good evidence that the Eheim P-Q curves are a bit optimistic. ...

I ran into a pump test on watercoolplanet.de that seems to indicate that Eheim's specs on the 220V 1046 and 1048 are actually a bit conservative.
It's in German/Deutche. If you don't read that, I've used Systran to produce a translated version and put it here. If you want to grab the numbers, here's the raw spreadsheet. I've edited it by removing unintersting-tome pumps and data columns. I may have totally screwed something up in translation - but I've tried not to.
They've got manafacturer's pump-head specs in bar and observed head in m (and I'm assuming that's m/h2o).
They've also got flow measurements for each pump through 2m of various sized tubing. At least I'm assuming that's what the German means.
I'm a little bit lost with converting flow rates at various restrictions into head/flow figures appropriate for a graph. I'm guessing the first step is to convert a liter of water into a cylinder the diameter of each size of tubing. Because the figures are in l/min, I know how long the "cylinder" is that goes by every minute (measured # of liters times length). This gives me velocity, which I can then use to calculate resistance. I'm pretty sure none of these are fast enough to be "turbulent" which means I should be using ??? to calculate resistance (or maybe just look up in a plumbers' table which might have the advantage of being observed data rather than output of a formula). Have I got that approach right? Anyone got a direct conversion formula (I'm just trying to satisfy my curiosity about the HPPS and data on that pump has been very scanty - it's an amazingly quiet pump, BTW...)
Bob

[satanicoo]

watercoolplanet.de also says cascade is in 9º place (last time i saw it), and diferenciates waterblocks with 0.1k temp diference, quite impossible to say AFAIK.

You should not take that much seriously.

[bobkoure]

Oh OK - hadn't looked at their waterblock ratings.
How hard can it be to measure flow through a tube at 0 head, though? I'm pretty sure they got the tube length and diameter right

[bobkoure]

Just took a look at their waterblock ratings. Very strange indeed.
I notice that most of the waterblocks have what appear to be Innovatek-style compression fittings on them.
I have one of those fittings around from an Innovatek agb-o-matic I bought a while back - hmmm... looks like this is intended to fit 8mm ID tubing?
I don't think low flow/pressure is enough to explain their ratings/temps, though...

[satanicoo]

I think the eheim pumps where tested by phaestus who realised the graphs where optimistic but im not sure.i really dont like the way they test the blocks. Oh well, after seeing the professional way they are tested here, thats something i shouldn't be surprised with...

I also heard that cascade they have there is a "defective" one... never knew what that meant...

[Razor6]

It's time for an update.

[satanicoo]

to add new pumps? yes indeed.

[satanicoo]

*deleteeeeed*

[BillA]

Originally Posted by bobkoure

Oh OK - hadn't looked at their waterblock ratings.
How hard can it be to measure flow through a tube at 0 head, though? I'm pretty sure they got the tube length and diameter right

how hard @ 0 head ?
I do not know how to do so
some tips ?

[bobkoure]

Well, in retrospect, I'm not totally sure I do either (semi-old post in old thread recently resurrected with a new post). I've done some reading and thinking about pumps since then.
I think what I was trying to say was "How hard could it be to measure output from a pump, though a measured length of tubing, tubing outlet at the same height as the pump outlet?" (Was thinking about just timing how long it takes to move a gallon, for instance.)
But even that doesn't allow for the residual pressure (positive or negative) coming from the relative elevation of the reservoir (or whatever you want to call the container that's feeding the pump). I'd guess the best you could do to minimize this would be a container with a very large cross-section, with the container outlet near the water surface and the pump inlet on that same level. I'd also guess that another way to do this would be to measure the rate from reservoir through the pump and tubing to the outlet without turning the pump on. Still not right as an unmoving rotor is going to present some resistance (much more if it's a closed rotor). Maybe remove the rotor for this measurement, try to keep pump inlet pressure slightly positive, and then subtract this flow from whatever the pump produces when running.

So - do I think WCP actually did any of this? I dunno. Probably not, though... IMHO the best we can hope for is that they used the same reservoir source setup for all the pumps in their spreadsheet so at least those numbers are comparable to each other. Might be a forlorn hope at that.