Prominent Gamma/L 0232 Flow Rate Test

@IH Fanboy

"minimum guaranteed performance at maximum rated capacity" makes sense to me.

There is a maximum rated capacity which is the capacity of the pump when all its settings are on maximum (i.e., 180 strokes per minute and 100% of possible stroke length). Prominent then tells its customers what the minimal guaranteed value is for this capacity. They do this so customers know which pump model to order.

Let's suppose you have an application which requires 30 L/H at 2 bar backpressure. You now know that you can order the 0232 model because Prominent guarantees that the 0232 delivers a minimum of 32 L/H when all setting are on max. You should even be able to dial the settings back bit to get your required flow. On the other hand if your requirement is for 40 L/H, you know that you should order a different model because your requirement is above what is guaranteed (i.e., the minimum it will pump) at the maximum rated capacity.

So Prominent is telling you the minimal flow you are guaranteed to get when the pump is running flat out. It may actually be able to pump a bit more but this minimum is the guaranteed amount. If I were Prominent, the way I would arrange to meet this guaranteed level would be to make the true maximal pumping rate attainable by the pump a bit higher that the guaranteed level. That would mean that you could have a little variation in manufacturing and still be sure that your pumps would meet the guaranteed level most of the time. And then I would do product testing as the pumps come off the line and reject any that fall under the guaranteed minimum.

To set a couple more examples:

- Your need is 31 L/H at 2 bar backpressure? That is below the guaranteed minimum performance at maximum capacity so go ahead and buy the 0232!

- Your need is 33 L/H at 2 bar backpressure? Don't buy the 0232. By another model. If you ordered the 0232, the one they ship you might possibly be coaxed to deliver 33 L/H, but it is not guaranteed.

@Bruce__H,

Your prose is nice. But it isn't expressed in such terms in the manufacturer's spec.

Quote from IH Fanboy

@Bruce__H,

Your prose is nice. But it isn't expressed in such terms in the manufacturer's spec.

How would you buy a pump from this manufacturer? Look at the spec sheet and then tell me, If you required 40 L/H would you buy the 0232? If you would, then what is your reasoning? If not then what is your reasoning?

Quote from Alan Fletcher

Since Rossi is referring to the Gamma L Manual, which states "Minimum flow at Maximum Pressure" it is obvious (to most people : there may be exceptions at the left-end of the bell curve) that Rossi is referring to "Minimum guaranteed flow at maximum pump settings of 180 strokes/minute, 100% stroke length, with 2 bar backpressure."

I don't believe that anybody is worrying about the minimum flow the pump can be set to.

Taking Prominent's recommendation that "sensible" stroke-length is between 30% and 100% (infinitely adjustable), and the programmable stroke rate can be set between 1 and 180 strokes per minute, the minimum "sensible" flow at 2 bar is:

1/180 * 30/100 * 32 l/hr = 0.053 l/hr. So YOU are off by a factor of 1/0.053 = about 20.

Of course, if you want to set the stroke length even lower (say 1%) and drive the pulses with the external control, you can 1 get ONE stroke per hour. That gives something like 10^-4 liters per hour.

We don't know yet if his claim is right or wrong. That is the purpose of this experiment.

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OK, I used the lowest rate given in the performance curves from the manufacturers spec, of 10% (18 strokes/min). So you are right, you can go even lower, and I misspoke. I should have said less "than 1 l/h". And since your point is valid, Rossi is off by at least 4 orders of magnitude but potentially up to infinty (and beyond).

Which doesn't help Rossi's case at all: when Smith cites 32 l/h, how does saying that Smith was wrong because 'this is the minimum', when it contextually is 'minimum guaranteed at maximum performance' help Rossi's argument in any way?

It obviously doesn't help Rossi's argument at all. If Rossi wanted to make a counter-argument, it would need to be something like 'yes, 32 is the spec'ed maximum but we ran the pump at180% of the manufacturers maximum specification under out-of-specification conditions'. Instead, he implies that this was the minimum flow rate of the pump. Which is incorrect.

In any case, now you are the one arguing that minimum as used by the manufacturer in context really means maximum. So we agree! (But not with Rossi). And perhaps you can understand if others, like IHFB were both confused by this and pointing to Rossi's incorrect statement which supposedly showed that Smith was 'wrong', when in fact his statement was reasonable within approximation, unless you want to quibble.

And this IS relevant because it is not possible to match the flow rate that Penon quoted with those pumps at anything close to 32 l/h. For example, 40 l/h doesn't come close, given the number of pumps.

Which was Smith's point, as you no doubt are aware.

And of course the other reasons that Rossi's statement is far-fetched, like running an expensive precision metering pump well outside it's specified metering range, remain.

But again, I sincerely appreciate your efforts to empirically answer this question, and look forward to your findings.

Quote from Alan Fletcher

No, the reason I've gone to all the trouble is the "Expert" Smith did all his calculations with the erronious reading of the spec as "Maximum guaranteed flow at maximum settings." This was featured prominently in IH's opening statements. It was Rossi who (in Mats' interview) pointed out that error. Nobody here ... me included -- noticed that fatal mistake.

Except that it's not in the least bit 'fatal' to Smith's conclusions of inadequate flow if the manufacturer's specification can be trusted. Rather, those ratings are fatal to Rossi's flow and heat transfer claims.

The only remaining hope for Rossi's argument is if the Prominent pump can be made to run at 180% of the rated performance of the pump.

Which is kind of like pulling a rabbit out of the hat.

So, we're waiting to see if your experiment pulls a rabbit out of the hat, metaphorically.

Quote from Alan Fletcher

0232 is their highest Gamma L (at 2 bar) 32 l/h -- to reach 40 you'd have to buy two

0240 is their highest Gamma X (replaces L) 40 l/h -- just buy one (unless you don't like running at maximum).

I agree completely (you appear to be reading the specs in the same way as I am), but I don't think Mr Rossi would agree.

I think that the measurement errors on the timed runs are pretty firmly under control now. Nice!

Quote from IH Fanboy

Sig, what does that even mean? You seem to be combining words in such a way that is not consistent with the manufacturer's spec, which literally states it using the following terminology:

"Minimum pump capacity at maximum back pressure." (32 l/h)

http://prominent.us/promx/files/987604_04_12_gammal_us.pdf

I submit that "minimum guaranteed performance at maximum rated capacity" is quite different from "Minimum pump capacity at maximum back pressure."

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OK, this obviously is confusing to some, and it's understandable confusion, since their use of 'minimum' practically means 'maximum'. But this isn't at all uncommon. For example, in electronics, the characteristics of the part (transistor, diode, transformer, etc.) is often spec'd as a 'minimum' when for design purposes, it's stated as it's max reliable (or 'guaranteed') rating.

And I gave the example of the 1/2 ton pickup truck which is analogous to how this pump is spec'ed.

It's important to remember that this is a metering pump. It's purpose is to provide precise flow control. So, if you have 2 bar of back pressure (which is the maximum that the manufacturer says you can have and still know that the pump should function correctly), the maximum capacity (or flow rate) is 32 l/h. You know that they mean the maximum (even though they use the word minimum), because they are stating that this is using the maximum stroke length (100%) and the maximum stroke frequency (180 strokes/minute). At one bar back-pressure, it's 36 l/h. And the 'correction factor' graph shows that this is linear with back pressure over the range they provide (down to .5 bar). If you extrapolate to 0 bar (atmospheric) this gives you 40 l/h. But they don't show this 0 bar correction factor, so it might not be exactly linear outside of the range they show. But it's extremely unlikely to be substantially non-linear outside of the provided range. This is why I bet Quatloos that Alan will measure less than 42 l/h. I've given some substantial error margin for measurement, to be safe.

The reason they use the word 'minimum' is because the pump is performing a pumping function against the fluid which resists flow (due to back-pressure and fluid resistance). So the manufacturer is stating that the pump will pump at least the amount given in the spec., and calling that 'minimum'.

So the pump will still reliably 'push through' (at least) 32 l/h under those conditions. But it's not going to push through any significant amount more than that either (to within the accuracy of the metering pump) because it is a precision metering pump designed to not over-pump or under-pump, assuming it's operating within it's specified range.

As (I think) you know, I'm using the words 'guaranteed performance' (which are obviously mine, not the manufacturer's) to help clarify the meaning of this specification to those not familiar with the interpretation of these kind of specifications. If you find that terminology confusing, or you think it's contradictory, than ignore it. It's how I understand this spec and other similar ratings in other engineering applications.

However, the specification provided shows the practical maximum (not the minimum) that the pump will deliver. And that is a fact. So if you don't like my explanation or terminology, you can come up with your own. But you still end up with the fact that this is the practical maximum of the pump. Not the minimum, despite Rossi's incorrect statement otherwise.

I hope this helps.

Quote from Alan Fletcher

Sooo .... there is a definite (25%) increase in flow from 0.15 to 0 bar

or 32% more than than the minimum guaranteed (etc etc) flow at 2 bar.

BUT: we don't know how good this pump IS until we get in range of a Prominent Spec.

Somebody posted low-backpressure curves : could somebody find them for me?

This seems a big enough jump to continue with the experiment.

The level-reading is very difficult and error-prone, so I'm going to order a digital scale of at least 0.01 kg resolution.
Without USB I'll film the readout for the whole run.

OR I'll put a digital clock next to the scale and take a photo of both of them at the beginning and end of a run.

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Alan, its here:

Prominent Gamma/L 0232 Flow Rate Test

(This is also the link that I've been putting in several of my responses)

The 'curve' is actually linear to my eye from .5 to 2.0 bar back-pressure. If you assume it's linear to 0 bar (as I just explained in my response above to IHFB), this would predict 40 l/h at 0 bar (with 100% stroke length and 180 strokes per minute).

Thanks again for your efforts.

Quote from ele

Bruce, only the people that had a complete knowledge on how the plant was made cold give you an answer.

Well we do have Mr Rossi's own words regarding the backpressure at the outlet of the Prominent pumps. In his handwritten notes regarding Rick Smith's supplemental report, Rossi says "But in our case the pumps have to push the water to a height that averages 1 meter, which corresponds to 1/10 of bar!!!"

I don't agree with this and it is possible that Mr. Rossi has made a bit of a mistake in his calculations. From an argument supplied by a "friend of Rossi's" earlier in this thread it is virtually certain that the backpressure at the pump outlet is almost 0.

We can agree, however that the backpressure is small.

And Randombit0 made an argument earlier that the inlet has a head of about 15 feet of water which is about 0.5 bar. That would be a maximum. I am dubious though. I don't think that there was any overpressure on the inlet. If there was it would contradict how Penon describes the system in his report.

Alan, before the control testing you will do at ~ 2 bar, we will not say what we're all thinking, which is that the pump will likely prove to be within spec at 2 bar, and that that will be evidence that your pump is representative of such Gamma/L pumps more generally.

We will also seek to find what merit there is in arguments to the effect that nothing at all can be concluded about Rossi's getup from your tests. (Regardless, there is still the matter of the "recirculator" to be dealt with.)

ETA: who knows how these things work when they're damaged or they've been operated out of spec for a long period of time.

Quote from sigmoidal

Alan, its here:

Prominent Gamma/L 0232 Flow Rate Test

(This is also the link that I've been putting in several of my responses)

The 'curve' is actually linear to my eye from .5 to 2.0 bar back-pressure. If you assume it's linear to 0 bar (as I just explained in my response above to IHFB), this would predict 40 l/h at 0 bar (with 100% stroke length and 180 strokes per minute).

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The curve is actually slightly nonlinear (concave up). You can see this if you use a ruler.

In my opinion, the conditions for one of the timed runs (run 06C) that Alan Fletcher performed today closely replicates the inlet and outlet conditions actually seen by the pumps in the Doral plant during the 1-year test. These would be 0 bar backpressure and an negative inlet pressure corresponding to pulling up water from a reservoir by about 1 metre or so.

Indeed the only significant physical condition in Mr Fletcher's rig that departs from the Doral conditions is the water temperature which was about 26C for Mr Fletcher and about 70C in Doral.