Bruce__H Member
  • Member since Jul 22nd 2017
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Posts by Bruce__H

    I'm absolutely sure that it is too early to estimate pumping rates. Nonetheless I am going to do it!!


    In the first video you can clearly visualize the water level climbing in the output hose between the 33 and 43 second marks. I have measured at several points in this time period and have found that each stroke raises the level in the 1/2" hose by about half a diameter. Converting to cm and calculating through gives a stroke volume of about 0.8 cm^3 per stroke. At this early part of the video the stroke length is set to 50% of max so this means that the full stroke volume is about 1.6 cm^3 per stroke. Finally, the pump is set at 180 strokes per minute = 3 strokes per second. So the Pumping rate per second is about 4.8 cm^3 per second or roughly 17.3 L/h.


    Lots of approximations here but we are most certainly not near 60 L/h which seems to be Mr Rossi's latest claim.


    My prediction for the 1.5 bar run is 40 L/h. I bet a million quatloos (which I think isn't very much ever since the galactic confederacy suffered that bout of hyperinflation).

    Since the pump has to overcome the difference between inlet and outlet pressure, does it mean that increasing the inlet pressure (for example by the recirculation pump) until the difference between inlet and outlet pressure is very low, will have the same effect ?

    This could possibly be tested by supplying the water to the pump from a tank positioned above the inlet of the Prominent



    If you look at the way the pump is built, the ball valves on its inlet and outlet would both tend to become unseated if the inlet pressure is higher than the outlet pressure. On the face of it this means that there is nothing much to stop fluid from travelling straight through the pump under these conditions. Let's call this "push-through". This could contribute to the phenomenon the Prominent manual is warning about.


    The extent of push-through will be modified by the position of the solenoid/diaphragm system. In its resting state, between strokes, I would guess that the diaphram should close off any flow and minimize push-through (I don't really know this however). When the pump is operating, the susceptibility to push-through will be different at different different portions of the pumping stroke.


    So the situation is complex. But this all means that when there is a pressure imbalance in favour of the inlet side the accuracy of the pump may depend on stroke rate. It may be of interest, therefore, to set up a situation where the backpressure at the outlet is smaller than the forward pressure at the inlet and see 1) if the pumping capacity is grossly above the rated rate, and 2) if it depends on the stroke rate of the pump.

    @THHuxelynew


    Hi THH. I am struggling to understand the calculations in your Excel worksheet. I understand that it would take some work but would it be possible for you to update your worksheet with more extensive comments on it showing where some of the constants are from and how the equations work?


    I also wonder if you could identify a textbook problem involving a heat exchanger with baffles and show that your worksheet handles it adequately and produces the known solution. This is a technique you have used in the past would be a check on the worksheet calculations.

    PS - what I'd like is for the ECW guys (and specifically E48) to read the above and answer. E48's answer to the conversation about erroneous HTC is that it would be Ok if the wind velocity was high enough, which could be got from a design with baffles. That is sort of true - though Wong left out any mention of baffles there is no requirement on him to do that. But the power argument knocks this on the head.


    I'll try to attract some attention for your calculations on ECW.


    In the meantime I'm working through your spreadsheet. I don't understand the mass velocity, G. Dimensionally, it seems to have units of a mass flux [Kg/m^2*s] rather than a mass velocity. And can you explain how this comes into the formula for deltaP and the rationale for that?

    THHuxleynew


    Does it change the energy budget if the fans for the heat-exchanger were drawing air rather than pushing it? In his deposition, Wong seems to believe that the fans were right up against the window openings and were meant to suck air from the exchanger box and expel it directly to the outside.

    The Prominent pumps on the E-Cat units at Doral are fed by a condensate holding tank sitting on the floor of the red shipping container. Penon, Smith, and one of the on-site technicians, Barry West all treat the pumps as having to suck up condensate from this tank. In recently released notes and in his interview with Mats Lewan, however, Rossi has begun suggesting that this tank is sealed and pressurized rather than at atmospheric pressure. The pressurization is apparently due to a "recirculator" sitting on the JMP of of the facility that Rossi has never spoken about before but now seems very important. If I understand correctly, the recirculator pumps condensate into the holding tank on the floor of the E-Cat plant which creates a head of pressure that then appears at the suction side of the Prominent pumps. I can't tell you how large that head of pressure would be, Rossi appears to be keeping it secret.


    I suspect that in disclosing the existence of this recirculating pump Rossi is creating room to argue that it is pressure at the inlets of the Prominent pumps that accounts for their high capacity. It would therefore be interesting to see if the capacity of the pumps actually does depend on inlet pressure. It would be a shame if you did your experiments, sold the pump, and then afterwards learned that Rossi is claiming that inlet pressure is the key to everything.



    In any case, adding a recirculating pump to the input will accomplish something between nothing ... and forcing water through the suction/dosing valves with a little modulation by the diaphragm.


    I understand your point about forcing water through the pumps with little modulation. If it is true then I don't understand the role of the Prominent pumps in the systems at all. But I think this is where Rossi is heading

    OK. I see your point although I don't think that Prominent would recommend this method of calibration if startup and shutdown errors were a real issue.


    On other fronts, I actually think you don't have to worry too much about changing output heights much in your experiment. No one really contests that the distance between pump outputs and the fluid levels inside the reactors at Doral was more than 1 metre (actually from the photos it seems less than that). It seems like measurements at just 1 metre head of water and 0 meters would address the most important issues squarely.


    What I think is more important is how pumping capacity depends on inlet pressure. This is pretty much totally ignored in the Prominent literature. I assume that is because they believe most setups will have the pump drawing up water from below -- thus producing a negative inlet pressure. But in his most recent release of information via Mats Lewan's website, Rossi seems intent on arguing that there was positive pressure on the inlet side of the pump. The amount of pressure is unknown but I think that any data characterizing maximal pumping capacity at different inlet pressures would be useful.


    The final thing to consider is something that I don't believe you can do much about. It is possible to argue that running a pump like this flat out at 70C for months on end is likely to change its operating characteristics and perhaps increase its maximal capacity. I think the mechanism would be something like the diaphragm fatiguing under high temperatures and with constant activity and perhaps allowing more water to enter per stroke. As I say, I'm not sure how one addresses this. Maybe you can think of something.

    Alan Fletcher


    Hi Alan.


    Did you know that this pump can be programmed to run a set number of strokes and then stop?


    I suggest that a simple way to conduct your experiment could be to run the pump at maximal strokes rate and stroke length for 100 strokes, or whatever you find suitable, then measure the output. Having the pump run for a set number of strokes appears to be available in the "batch" and "calibration" modes of the pump.


    There are some good instructional videos for Prominent pump available on the internet. Here is one walking you through how to use the front interface for programming the pump operation


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    And here is one that covers pump calibration. This is a particularly good one because it looks to me as though the setup in use might be one you could adopt for your experiments


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