How to overestimate water flux by wrongly positioning an instrument

Report written on: 19/04/2016

This Post was triggered by a discussion concerning the energy measurements published in this document of May 2013 (Provisional Patent Application US61/821,914) and by the statements of a user on the 22passi Blog (nickname: Hermano Tobia), who does not believe that a possibility exists for outrageous errors in measuring the quantity of water drained from a container named “water reservoir” when this is done by using a “Flowmeter” as the one mentioned in the said document. In particular Hermano Tobia, referring to an image that likely documented visually the setup adopted (image referred to as Figure 1), stated (translating from Italian):

The pipe with the flow meter is connected to the Tellarini self-priming pump that is in the blue bucket where the condensed vapor is conveyed, thus I don’t believe your hypothesis is plausible.[10 April 2016 23:03]

Hermano Tobia referred to the technical criticism previously expressed by Mario Massa, who had highlighted how the improper choice made for positioning the “Flowmeter” was such to potentially cause a malfunction of the instrument. In particular Mario Massa in his comment had evidenced that:

… that palette flowmeter is mounted in a manner that is absolutely incorrect: it is in the highest point of a pipe that flows into a reservoir.” [10 April 2016 20:22]

i.e. the “Flowmeter” (in particular a litre counter as normally used in households for drinkable water) was wrongly positioned if aimed at correctly recording the true flux of water.

Figure 1 shows the set-up adopted for that test and one can readily see how the “water reservoir” (the blue container) is positioned below the instrument.

Figure 1 – Reservoir equipped with a “Flowmeter” positioned on top of the pipe runs

Figure 1 – Reservoir equipped with a “Flowmeter” positioned on top of the pipe runs

To convince those who may doubt that significant functional issues may arise when the conditions are not met for a complete and constant filling of the pipe where water is present and flows, a test setup was realized (Figure 3) similar to the one in question. By using a pump, water is drawn from a reservoir, and the quantity of water is measured by initially using a Watermeter by Gioanola (*) model DALF/25-1 (Figure 2):

Figure 2 – 1″ Watermeter by Gioanola

Figure 2 – 1″ Watermeter by Gioanola

In the first test the Watermeter size 1″ and the relevant connections are positioned in a similar fashion as visible in the image in question (Figure 1) i.e. in the functionally INCORRECT manner adopted for that test.  The overall set-up is visible in Figure 3:

FFigure 3 – INCORRECT 1” Watermeter Set-up

Figure 3 – INCORRECT 1” Watermeter Set-up

 

With such setup we will determine the actual quantity of water flowing per unit time and compare to a reference measurement.

The verification of the clumsily installed instrument’s reading  is done by filling a glass container of known volume (1 Liter in our case) with water drawn by the reservoir, and by measuring the time needed to fill the reference 1 Liter container. The value recorded with this method is then compared to the instrument’s reading.

In order to document the main phases of the test a brief Video (n.1) was taken.

Summarizing the main data of our first test, water starts to flow into the 1 Liter container  at minute 0:26 of the video, and the container is filled completely at minute 1:13. During this interval the roller counter that indicates the quantity of water flowed has completed 3 turns, that correspond to 3 Liters of water estimated by the instrument.

By analyzing the data one can compute the time necessary to pump 1 Liter of water into the glass container. Such time is 47 seconds, thus the water flux is estimated about 76.6 liters/hour.

If one were to trust the reading of the Watermeter, measuring 3 liters, and considering the same 47 seconds, one would erroneously estimate a water flux of about 229.8 liters/hour thus with a 200% measurement error.

In the second test the set-up with the 1” Watermeter as modified in order to ensure a CORRECT instrument functionality, by introducing an upward bend downstream from the Watermeter  The overall setup realized is visible in Figure 4:

Figure 4 – CORRECT 1” Watermeter Set-up

Figure 4 – CORRECT 1” Watermeter Set-up

In order to document the main phases of the test, a brief Video (n.2) was taken.

Summarizing the main data of our second test, water starts to flow into the 1 Liter container  at minute 0:23 of the video, and the container is filled completely at minute 1:11. During this interval the roller counter that indicates the quantity of water flowed has completed 1.1 turns, that correspond to 1.1 Liters of water estimated by the instrument, with an error within 10% roughly.

By analyzing the data one can compute the time necessary to pump 1 Liter of water into the glass container. Such time is 48 seconds, thus the water flux is estimated about 75 liters/hour.

For the third test  a 3/4″ Gioanola Watermeter model USLF/20 (Figure 5 and Figure 6) was used:

Figure 5 – 3/4″ Gioanola Watermeter

Figure 5 – 3/4″ Gioanola Watermeter

Figure 6 –3/4″ Gioanola Watermeter

Figure 6 –3/4″ Gioanola Watermeter

In this case, again the Watermeter size 3/4″ and the relevant connections are positioned in a similar fashion as visible in the image in question (Figure 1) i.e. in the functionally INCORRECT manner adopted for that test.  The overall set-up is visible in Figure 7:

Figure 7 – INCORRECT 3/4″ Watermeter Set-up

Figure 7 – INCORRECT 3/4″ Watermeter Set-up

Again the verification of the clumsily installed instrument’s reading  is done by filling a glass container of known volume (1 Liter in our case) with water drawn by the reservoir, and by measuring the time needed to fill the reference 1 Liter container. The value recorded with this method is then compared to the instrument’s reading.

In order to document the main phases of the test a brief Video (n.3) was taken.

Summarizing the main data of our third test, water starts to flow into the 1 Liter container  at minute 0:30 of the video, and the container is filled completely at minute 1:26. During this interval the roller counter that indicates the quantity of water flowed has completed 2.7 turns, that correspond to 2.7 Liters of water estimated by the instrument.

By analyzing the data one can compute the time necessary to pump 1 Liter of water into the glass container. Such time is 56 seconds, thus the water flux is estimated about 64.3 liters/hour.

If one were to trust the reading of the Watermeter, measuring 2.7 litri, and considering the same 56 seconds, one would erroneously estimate a water flux of about 176.8 liters/hour thus with a 175% measurement error.

In the fourth test the set-up with the 3/4” Watermeter was modified in order to ensure a CORRECT instrument functionality, by introducing an upward bend downstream from the Watermeter. The overall setup realized is visible in Figure 8:

Figure 8 – CORRECT 3/4″ Watermeter Set-up

Figure 8 – CORRECT 3/4″ Watermeter Set-up

In order to document the main phases of the test, a brief Video (n.4) was taken.

Summarizing the main data of our fourth test, water starts to flow into the 1 Liter container  at minute 0:31 of the video, and the container is filled completely at minute 1:28. During this interval the roller counter that indicates the quantity of water flowed has completed 1.0 turns, that correspond to 1.0 Liters of water estimated by the instrument, with negligible error.

By analyzing the data one can compute the time necessary to pump 1 Liter of water into the glass container. Such time is 57 seconds, thus the water flux is estimated about 63.1  liters/hour.

Conclusions

The data shown help in understanding how large an overestimate can be caused by an incorrect instrument placement when measuring water flow.

Such behavior of “palette” counters is well known to specialists in the field, chosing to install the instrument in that way the risk to overestimate is high and the measurement could become completely unreliable.

(*) It is worth  noting that in order to avoid malfunctions, Gioanola published a  series of installation instructions (to which installers must comply) in order to ensure the necessary conditions for the correct functionality of their Products.

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Una risposta a How to overestimate water flux by wrongly positioning an instrument

  1. Jed Rothwell ha detto:

    This article is a helpful. Thank you for going to the trouble to test flowmeters and for writing this.

    I have made many mistakes with laboratory scale flowmeters. I have accidentally caused errors as large as the ones you describe. It is very important to read the manufacturer’s manual. It will list many ways to set up the flowmeter incorrectly, such as the ones you describe, and also with backflow and other problems.

    The experiments conducted by Defkalion were invalid because they set up the flowmeter incorrectly and allowed backflow. This is described here:
    http://lenr-canr.org/acrobat/GamberaleLfinaltechn.pdf

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