Talk:Flow measurement: Difference between revisions

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--Mlloydmequon 17:29, 31 July 2006 (UTC)MikeIs this article a business directory listed at the bottom? is that policy?

I have deleted the entire "Companies selling flow measurement devices" section. Wikipedia is not a Web directory, and this list is an open invitation for spammers. If there are any truly notable companies that are worth a mention, they will be notable enough to have their own Wikipedia article, and we can link to that. —Caesura^(t) 12:23, 17 December 2005 (UTC)

31July06: The article is useful as it is. But it suffers a bit from its apparent perspective in potable water distribution. To wit: It omits several important classes of flowmeters:

1) Flowmeters providing visual flow information such as:

a. rotameters with poppets positioned by flow/gravity interaction
b. totameters  with poppets positioned by flow/spring interaction
c. vane type flowmeters

2) Low cost "mechanical" flowmeters

a. paddlewheel flowmeters with pickups using reed switch or Hall effect or optical or ?? sensors
b. turbine flowmeters with various pickups

3) Other flowmeter types:

a.  Fluidic oscillation meters (related to vortex shedders, but different enough to justify their own mention)
b.  Target meters (related to pitot meters, but, again, different enough for mention).

4) Beyond this, venturi meters and orifice meters should be classified as "head flowmeters" or something similar. This would then be a reasonable place to include open channel flowmeters such as:

a.  V-notch wiers
b.  Parshall flumes.

I'm sorry that my expertise is not up to the task of providing actual improved text for the Wiki entry. Hopefully, some expert will take my (probably still incomplete) list and use it to extend the entry.

Is that density or viscosity of fluid will affect the flow

Dear all,

Is that anyone come across this issue before? How does the density or viscosity affect the total flow? for example, with different density of gases, will they have same quantities if their flow with same units (1000 m3/hr, etc)?

Regards, Lee

Venturi meters

Is it really enough to say that a venturi meter constricts flow 'in some fashion'? I believe a venturi flowmeter must use a venturi tube, just as a orifice plate meter must use an orifice of a very specific size in order to function.

Determining mass/flow rates etc

Hi

I need help on a formula that I can use in spreadsheet or database to calculate total quantity of fluid passed over a period of time.

Example pressure 25 psi, pipe bore 2 inches, length 12 feet, fluid = water time 20 minutes.

I would appreciate an answer from anyone who can spare the time please

Nb I would be using MS Excel or Access (sad I know but limited resources).

Thanks

Allan

Calculating flow rates (for Allan)

Unfortunately Allan, the calculation isn't as simple as your question implies.

The simplest equation for calculating flow looks like this:

V = Av

where:

(V) is the Volumetric flow rate (in your example, probably in cubic feet per minute [cfm])

(A) is the cross-sectional area of the pipe. In your example the area would be the pipe radius (half the diameter or 1 inch) squared times pi (3.14) or 3.14 square inches. For most flow equations in standard units, you will want the area of the pipe in square feet, which in this case would be 0.0218 square feet.

(v) is the average fluid velocity. This is where your example gets harder. The flowmeters in this article really only measure fluid velocity because the pipe size (and thus the cross-sectional area) is fixed by the meter itself. If you don't know the fluid velocity in your example, you can't calculate flow. If we could measure flow with the example information you provided, flowmeters would be unnecessary, you could measure flow with a pressure gauge and a tape measure.

However let's say you did know the velocity, and you didn't list it because you didn't know it was important. Lets say for example it's 20 feet per second (fps). The volumetric flowrate would be 0.0128 square feet times 20 feet per second or 0.256 cubic feet per second. Cubic feet per minute is a more standard unit of measure, so converted that would be 15.36 cfm.

There are 7.48 gallons in one cubic foot of water, so in gallons per minute (gpm), that is 15.36 times 7.48 or 114.9 gpm.

If it was mass flowrate that you wanted, the above equation is still necessary. The following equation is then applied:

m = Vρ

where:

(m) is mass flowrate

(V) is volumetric flowrate from above

(ρ) is the density of the fluid (in this case water)

Density of pure water is a function of temperature. If the temperature of the water in your example is constant and known, you could look up the density on a table. For now, we will use 62.3 pounds per cubic foot, which is the approximate density of water at 70°F.

Using the volumetric flowrate we calculated above, the mass flow rate would be 15.36 cfm times 62.3 pounds per cubic foot or 956.928 pounds per minute.

After you calculate the flowrate the rest is the easy part. Take the flowrate (we'll use the 114.9 gpm from above) and multiply it by the time that has passed to get total volume. From your example we will use 20 minutes times 114.9 gpm and we see that a total of 2298 gallons of water have passed through our 2 inch pipe in the 20 minutes alloted.

Although I'm sure this entry didn't get you closer to your spreadsheet equation, I hope it shed some light on flow calculation in general, as well as the variables required to calculate flow.

Brandon W.

Dear Brandon Kindly let me know if the medium is air for the above what would be the flow if the input pressure is 6kg/cm2 and the does the size of the pipe matter and what is the relation. If an orifice is used in the valves what effect does it make. I have an enclosure of say 50cuft and would like to purge out 100cuft of air with a 6kg/cm2 pressure air with me what would be the size of the tube at inlet /outlet and what would be the time required for the same.

Pramod

Query for Instrumentation Engineers

How would an instrumentation engineer differentiate between the measurement of flow and pressure? Plz help —The preceding unsigned comment was added by 61.0.17.157 (talk) 02:00, 3 April 2007 (UTC).

WP:NOT

Wikipedia is not a place for advertising. I took out an enormous quantity of far-too-specific text and pictures with a whole bunch of registered trademark logos on it. The information duplicated other info that was found in the rest of the article, was way too specific, linked to proprietary websites and generally looked like a paste from a company representative. I re-worked what I could but most of it I just took out. WLU 20:15, 18 July 2007 (UTC)

diameter of pipe

how to find the required diameter of pipe if we know discharge,velocity of flow and density of fluid in sewerge net work —Preceding unsigned comment added by 121.247.154.101 (talk) 10:59, 9 April 2008 (UTC)

Flow of water at standard pressure of 3bar, Calculation of pipe dia. to be used?

When water needs to be pumped for a distance of 3 kilometers, and a constant pressure of 3 bar is supplied what is the optimal diameter of pipe that can be used? What formula can be used to calculate the diameter of pipe to be used when the pressure substance (water) and distance are known. Can anyone provide me with information? Arjaa (talk) 09:14, 4 August 2008 (UTC)

Wikipedia talk pages are not for help with an articles subject -- they are about the articles themselves. User A1 (talk) 11:51, 4 August 2008 (UTC)

1. Explain the difference between a quantity metre and a rate-of-flow – flow metre. —Preceding unsigned comment added by 122.55.116.49 (talk) 07:38, 29 July 2009 (UTC)

I hope that is not is not a homework question. User A1 (talk) 09:29, 29 July 2009 (UTC)

Flowmeter versus flow meter

Why does the text use "flow meter" instead of "flowmeter"?. There are lots of instances where concatenating the word "meter" with the preceding noun is common i.e. calorimeter, odometer, speedometer, ammeter, barometer, anemometer, velocimeter, etc BluesLewis (talk) 01:19, 11 December 2011 (UTC)

I don't know. Use it once or twice in the article and see if use spreads? I like to saw logs! (talk) 08:36, 11 December 2011 (UTC)

Both version are used and accepted in industry. Wikipedia seems to be favoring "flow meter" in all the pages I have seen.AussieMueller (talk) 20:39, 23 April 2013 (UTC)

Ultrasonic flow meters (Dopper and transit time)

Updated the information on ultrasonic flow meters to make it clear that Doppler and transit time are two separate methods. Also reduced the marketing spin about natural gas (these technologies are used for so much more). I will be updating the Ultrasonic flow meter page shortly for similar clarity issues.AussieMueller (talk) 20:16, 23 April 2013 (UTC)

Calibration - the stopwatch-and-bucket method?

One commonly-used method of verifying the accuracy of a liquid flowmeter (particularly if the liquid is water) is to let the liquid flow at some measured flow rate into a bucket for a specified period of time, and then weigh the liquid (taring the bucket, of course). Mass of liquid divided by time is the mass flow rate. It's extremely low-tech, but can yield surprisingly good accuracy. Accuracy can be improved by increasing the flow time - this reduces errors due to reaction time with the stopwatch, but you need a bigger bucket and scale. 152.51.56.1 (talk) 13:48, 14 June 2013 (UTC)

Already mentioned in the mechanical flow meter section. Ray Lightyear (talk) 14:11, 14 June 2013 (UTC)

It's mentioned there as an analogy (and a good one), but it's also used as the actual verification method for various liquid flowmeters. Since we have a Calibration section with specific information for the use of radiotracers, some less complex methods should probably be suggested - including verifying one meter with another, more accurate, one connected in series.152.51.56.1 (talk) 19:32, 25 June 2013 (UTC)

Unclear and wrong statements

" The density for a liquid is almost independent of the liquid conditions; however, this is not the case for gas, the density of which depends greatly upon pressure, temperature and to a lesser extent, the gas composition."

There is so much wrong in this statement. First of all saying density of liquid is almost independent of the conditions is wrong. Density of water changes ~4% between 0 - 100 degree Celsius, how is that not a significant change? It would be right to say relatively less dependent compared to gas. Second density of gas is depends to a lesser extent on the gas composition. What does this even mean? This implies if i mix gases its density doesn't change, which is completely wrong. Changing a fixed volume of pure hydrogen to same volume of 50% hydrogen and 50% Argon increases is density by 40 times.Ray Lightyear (talk) 14:24, 14 June 2013 (UTC)

Mass Air Flow meter section

I think that section confuses MAFs and AFMs (Air Flow Meters) which measure volume rather than mass. The two specific examples I'm aware of are moving-vane type AFMs which incorporate a temperature sensor so that the engine control module can calculate air mass from the measured volume and temperature; and a heated-wire type MAF which measures mass directly by determining the current necessary to maintain a platinum wire suspended in the air stream at a predetermined temperature. Dbeierl (talk) 04:05, 8 July 2013 (UTC)

Dog mix interference?

The section "Turbine Flow Meter" mentions a phenomenon called "Dog mix interference" which only appears on Wikipedia and copies of Wikipedia articles...and nowhere else. I'm virtually certain it's a translation error, but am unsure what to replace it with. Turbulence?

(The only other place I can find that isn't a copycat article is Water metering#Turbine meters, which is pretty obviously a copy-paste from this article, or vice versa)

Cicero225 (talk) 17:36, 2 April 2014 (UTC)

Good grief, that's been there since December 2010![[1]] (Revision history search is great.) I suppose it might be a faulty translation of "liquid/solid two-phase flow" or some such, maybe even a euphemism for sewage, but rather than resolve that I've just gone ahead and replaced the whole sentence about accuracy - that suggestion that all sizes are accurate to 0.2 l/s had to go too. I'll do the other article too. Good catches! NebY (talk) 18:33, 2 April 2014 (UTC)

Viscometric flowmeter

I've copied the following from my talk page, where it was posted under the heading "flowmeters and reliable sources", so that the discussion is kept with the article and other editors can join it. NebY (talk) 19:40, 28 December 2015 (UTC)

Dear NebY,

Thank You for your attention.

I must take issue with several things.

First, I suggest that the class being referred to as 'linear resistance meters' is too easily confused with apparatus for measuring ohmic resistance. I suggest returning to 'Viscometric flow meters' and moving the somewhat hypothetical 'multi-tube', and porous element meters to their own sub-classifications of 'pressure differential types'.

Also, I don't see the point of pointing out that a longer tube yields a larger pressure differential, this is evident from the equation. Indeed, a reason the viscometric flowmeter became viable was improvement in technology to take reliable and inexpensive low differential voltage measurements, which correspond with shorter sensing elements. Indeed, shorter elements are preferred since they do not induce as great a pressure drop in the system as would a longer element.

Also, these devices are not restricted to 'very low flows', and are not restricted to laminar flows except in the special case of those 'pressure differential' types which do indeed use the Hagen-Poiseuille relationship.

Also, I'm not sure why the US Patent office does not classify as a reliable source. Seems independent, rigorous, and staffed by reasonable subject matter experts. On further research, I see how to properly cite a patent as a sounrce here: https://en.wikipedia.org/wiki/Template:Cite_patent

Also, there is the 'viscometer', and there is the 'flowmeter', and there is a 'viscometric flow meter', which performs either function at a given time.

Also the last edit seem to infer flowmeters using "a bundle of such tubes, or a long porous plug" are governed by the Hagen-Poiseuille relationship, and this is not the case.

Lastly I suppose I would say it is somewhat misleading to characterize the viscometric flowmeter as having a similar temperature related error characteristic as the super-set of linear resistance meters, as viscometric flow meters specifically measure and compensate for temperature variation over some range. This is the charachteristic which separatesthem non-temperature compensated implementations.

Please advise. Regards, Herr baumeister (talk) 02:52, 21 December 2015 (UTC) Herr Baumeister. — Preceding unsigned comment added by Herr baumeister (talk • contribs) 02:21, 21 December 2015 (UTC)

Italic comments/rebuttals/etc inline with below are from Herr baumeister in response to NebY's edits of the section on 'Linear Resistance Meters'.

First, concerning the text I've added:[2]

• The term "linear resistance meters" is taken from the ASME report I cited. I don't know why you think that "linear resistance" in an article about flow measurement would be taken to mean electrical resistance. 'I' am not confused on the term, however; readers might easily be.
• The construction using single tubes, multiple tubes or a porous plug is described and illustrated in the ASME report and in Miller's "Flow Measurement Engineering Handbook", which I also cited. Your description of one type as "somewhat hypothetical" suggests you're unfamiliar with the sources and with the products of Meriam, Furness Controls and others. I prefer we stick to the issue at hand, not anyone's familiarity with a given product. It increases the possibility of a deterioration of our discussion.
• On Wikipedia, we don't simply present equations and expect the reader to deduce key design considerations from them. In general I agree, but in this specific case, the deduction requires only simple algebra, which should be well within the grasp of anyone researching flow measurement technologies.
• The linear resistance meters described are all restricted to flows with low Reynolds numbers, below the turbulent flow range. Again, that's in the sources. True, but the Reynolds number range is not an absolute requirement. It is more useful to the reader to realize the sensing element geometry can be optimized to produce laminar flow. In fact, citing a Reynolds number causes one to ignore the issue of sense tubing tubing. This is why it was removed.
• The flow through capillary tubes is explicitly described in the ASME report as given by Poiseuille's equation. This is not exactly an error in the report, but well, it is an error. There is no provision in Hagen Poiseuille for the pressure drops associated with the recombination of flows from the capillaries. Hagen Poiseuille deals only with a single tube.

Second, concerning the "viscometric" flowmeter you describe:[3][4]

• The only source you have provided is a patent. A patent is not a reliable source for the existence of a device, even in prototype form let alone as a commonly available product or as a device that is commonly in use. A patent is not even a reliable source for the feasibility of the device; patent officers don't have to consider that. Nor is it a reliable source for terminology; patent officers don't have to judge whether terms are used conventionally or evaluate them as neologisms. Well, we will have to disagree on the use of a patent as a citation, as it is not so far as I can see against Wikipedia policy. Additionally, when and how a possible neologism becomes common useage is an interesting process. Since the device was awarded the patent based on novelty, it seems the use of a new word may be in order. Clearly the device under question (viscometric type 'linear resistance' meter is different than the other types (multi-tube and porous element), significantly so that it was after examination awarded a patent. Seems to me this is a very reasonable test of technology which has a combination of newness and merit to warrant inclusion.
• You have provided no other sources for the existence of this "viscometric" flowmeter. No, but I have seen the technology used recently in mass spectroscopy equipment manufactured by Thermo-Fisher. The patent is certainly more neutral than would be a user Thermo-fisher manual.
• I have asked you to read Wikipedia:Conflict of interest. I hope that you have and that you would declare if you have a connection with that patent. Below comment. The patent is abandoned I see anyway, so no-one should be able to attain any benefit from it's citation. Indeed, taking the material further into the public domain by citing the patent would go against any possible conflict of interest.

Third, I note that two later edits have come from IP 98.235.35.58.[5]

• These introduced errors concerning existing flowmeters, removed sources and added material about your "viscometric" flow meter, this time without any sources. They also introduced the bizarre claim that a flowmeter that causes a reduction in flow thereby introduces a measurement error, going on to promote the "viscometric" flowmeter. I'm going to reinstate the previous text, without those errors, with sources and without promotion.
• @Herr baumeister:, the coincidence of the IP edits with a similar purpose following so close on your own means that I have to ask you to be aware of the Wikipedia:Sock puppetry policy. Editing logged-out, editing with another account to give an impression of multiple editors, and various other practices are contrary to that policy. The policy page describes it better and in detail, and I do recommend it. NebY (talk) 21:12, 28 December 2015 (UTC)An oversight on my part I assure you. There was no intention of sock puppetry in any form. Harrrumph.

Dear NebY, First with regard to a technical error about increasing the tubing length and the associated pressure induced flow error....... The actual flow of any device under test does change as a function of backpressure (hydraulic loading). Contrary to what we were taught, fluids compress. Additional backpressure due to a measurement device having a longer (rather than shorter) flow sense tube (given identical radius) will cause additional compression of the fluid, changing mass in a given volume of fluid. For this reason, regardless of the source (cited does not necessarily mean correct) I removed your insertion regarding the suggestion to improve resolution by increasing tube length. The tube selection based on modern instrumentation sensitivities is the correct engineering approach. Second, the previous edit separated the single tube 'viscometric' flowmeter from the other types which were introduced and wrongly asserted as conforming to Hagen Poiseuille. Therefore, it made sense to separate the single tube laminar flow device from the multi-tube and porous element types. Additionally, the single tube type (viscometric) can indeed directly calculate viscosity in traditional units, based strictly on Hagen Poiseuille, whereas the other types (multi-tube and porous element) cannot. So it seems entirely appropriate to create a sub-class of linear resistance measurement types. Last, Regarding patents as sources, though patents are not included in or excluded by the Wikipedia policy, and since Wikipedia policy acknowledges that even among scholarly sources there is a variety of robustness of review, one could reasonably argue within the interest of providing additional sources of study that an abandoned patent has a reasonable chance of furthering a readers knowledge without chance of providing falsehoods......at least no greater chance of promoting what is false than any other type of citation. I ask what is a citation fundamentally? They are not by any means validation and proof of truth. One must follow the citation and ultimately make various judgements. Since policy regarding patents is not in the guidelines, I suggest this topic of truthfulness and reliability of citations, particularly as specific patents compare to currently accepted citations, be forwarded to the appropriate Wikipedia policy body.

 Rebuttals/comments to immediate previous post above added in italics. 

Herr baumeister (talk) 01:49, 29 December 2015 (UTC)Herr baumeister