Sensors - Monitoring Flow in Gallons per Minute (GPM)

Hey Kilgore,

My plumbing knowledge isn't as good as I wish it were but if I understand you, this is a rather heavy and thick walled pipe? And, I am not aware of the other constraints, but if you were able to isolate a given section of pipe between two flexible (rubber?) couplings (perhaps on a downward slope) could you not monitor the weight and extrapolate the flow using load cells? This could also be used to indicate a plugged pipe.

Load cells could also be placed at pipe supports without isolation plumbing but the calibration curve would be dependent on the influence of adjacent plumbing.

Everything else I can think of has to penetrate the pipe which counts it out.

Excellent--I will start looking for them--Any more specifics on them?--Brand, type, durability, etc.........

Thank you--I didn't even think about it, but dredging is close to what we have. Our material is classified and is within a small range of size, just not metered well--Clumps and surges of the material. This may be a perfect avenue--Thanks gsuhas and GA from me.

Trout

Thanks for GA.

Will you please let me know the ID of the lining, lining material and the range of flow rate?

As the material is not radio active, there should not be any problem in measuring flow of water with sand. Being through bore without any obstrtuction, no clogging problems will be there. Besides, no pressure drop will be there provided, we can use same size flow meter as that of pipe ID (for flow rage reasons)

With above data, I can suggest you exact size etc for the flow meter.

Just for your information: I am heading the India's largest flow calibration rig, and developed magnetic flowmeters up to bore 2400 mm. Also worked with commisioning of the meters on dredgers.

You are right Babybear.

Ultrasonic may also be a solution. The flow meter will not add any pressure drop, as in case of magnetic flowmeter. The meter components may be fitted directly above the existing pipe line, without cutting/ creating gap in existing line.

But accuracy may not be as good as magnetic flowmeter. Accuracy depends upon the alignment of the elements and the materials of pipe line including lining material.

But it may proove cheaper, if cost constraints are predominent, than the accuracy.

Hello gsuhas:

Ultrasonicis was my first thought, though I was not sure you could get it for this ~ 45 cm pipe. It seems they go up to 60". I am typing this from memory (which is not good!. As I am now replying to a different question and let the page go. Though it will be on the post I replied to the original thread on.

Thank you for the note. Take care.................

Clamp on type Ultrasonic has no size restriction. Anyway, you will be fitting transreceivers on your pipe. Only thing you need to clamp those very accurately.

Some link

http://www.krohne.com/OPTISONIC_6300__DLC.11512.0.html

http://www.sierrainstruments.com/products/205data.pdf

Hello Kilgore Trout:

I am not sure if this will be what you are looking for, as it looks as if you have to fit it as a joint between two pipe lengths.

http://www.globalspec.com/FeaturedProducts/Detail/Malema/Electromagnetic_Flowmeter_MLDZ_Series/27272/0

The spec' above is for a manetic sensor whos site is above that.

======================================================

This is a search page for 45 cm pipes as you have.

http://www.google.co.uk/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLJ_enGB294GB294&q=ultrason+flowmeter+for+45+cm+pipe

You two are a goldmine--I have got a date with my wife and some work this weekend, but I promise to make time for you and respond soon--THANK YOU.

Hello Kilgore Trout:

Have a great weekend and get your wife a drink on me!

I appreciate the thanks. All I did was have that 'light buld moment', or it would be if I could spell! And just used your phrase as a search, and it worked. More important, I hope you find the correct type and size of whatever system and, it works and gives no problems.

I think gsuhas had a pretty good idea. Depends on whether flow interruption and fitting the Magnetic type in-line is suitable? Sorry gsuhas, I forgot the proper name).

Good luck..............

I am glad you are back and as always, happy to help out.

I started going through some of the links--One of them looks like a similar system to what we have--I think we are on the right track. Tonight or tomorrow I will be able to sit down and look all of them over.

Hello Kilgore Trout:

why thank kind Sir, and it is good to be back!

What links were you viewing, if you do not mind me asking?

As I said I was not at all sure whether the ultrasonics would work on such a large size pipe, as the first searches I did brought a maximum size of half an inch! I thought I was on a loser, but tweaked the search parameter and got what I sent. Doesn't mean to say it will work, but, I hope it does and it is none invasive, so no cutting and joining..............

Thanks for complements. It is not so great on our side. It is just sharing the experience, what so ever we have. I, and almost all at CR4 believe that all experience, need not be counted in terms of finacial gain. Distributing the experience gives different kind of pleasure.

Note on magnetic and Doppler shift flow meters: Pipe must stay totally filled at measurement point, for these are actually velocity meters.The flow is calculated on the area of the pipe times the velocity,so a partially filled pipe will give erroneous reading.Ultrasonics are also velocity meters, so the same applies. There are meters designed to measure partially filled pipes,and they use a level detector and an algorithm to calculate area of fill of the pipe,and factor in velocity to get flow rate. Flow rate can be converted to any desired engineering units (Cu ft min, GPM,GPD,etc) Hope this is helpful.

You are right Guest. Mag and ultrasonic FMs need fully filled pipes for accurate results. Though actually these meters measure velocity and flow rate is velocity multiplied by area of cross section of the flow, practically, these flow meters are calibrated directly in tems of Flow Rate. Thus, measurement of actual cross sectional area is not done or needed. Both these flowmeters are designed to show the flow in any engineering units... LPM, LPS, M3/hr, GPM, GPD.... whatever you need.

There are flow meters which are designed to measure flow in partially filled pipes. Even magnetic flowmeters are there, which are designed for partially filled flow. But these are way highin cost, and one need not at all think in favor of these, as it is very simple to get full bore flow.

I beg to differ on the necessity of calculating cross sectional area.At some point in the algorithm that derives flow, there have to be at least 2 factors,since flow is a dimensionless number:Velocity, and area.IF the pipe is full, the area is fixed,and is factored in during calibration of the meter. As I stated, the meters are velocity meters, and this is only one factor of flow.The area of a horizontal pipe changes non-linearly with percent of fill, so in a partially filled pipe, an algorithm must be used to derive flow from these factors. As I also stated, there are meters used to measure flow in partially filled pipes, but these must incorporate method of determining percent pipe fill to calculate surface area of the measured variable.The magnetic sensor portion only measures the velocity.Marsh McBernie ($$$$) makes such a unit.It uses a bubble tube to determine pipe fill (level,aka:surface area),and a magmeter to determine velocity.The entire sensor mounts inside of the pipe, and different plug-in modules(E Proms) are used for different diameter pipes to give proper algorithm calculation. The flow rate can be displayed or recorded in any desired units of measurement(Engineering units),such as Million/Gallons/Day,(MGD) Gallons per minute(GPM) Liters per minute(LPM) or any other measurement or totalizer system. Hope this clears it up. He that knows not, and knows not that he knows not, is a fool, shun him

1. I am not talking about the partially filled pipes. What I said is fully filled pipe flow. In fully filled pipe, though theoretically flow is area X flow velocity, actual measurement of cross sectional area is is not needed. The output current is calibrated in terms of flow rate, which indirectly takes care of the cross sectional area.

In all types of flow meters, you can choose any engineering unit. It is not a monopoly of partially filled type flow meters. This just a internal programming.

2. For the technical discussions, you need not call any body fool. You have come to your own low level, that too with cover of name "GUEST". Be non-coward and come with some name. Though you take some name, knowbody knows you personally.

Besides, I introduced myself as I am heading some good, internationally accredited flow calibration laboratory, which as got connections with many other international flow calibration laboratories. In this capacity, I had a chance to see many other laboratories including flow calibration laboratory of Nmi, The Netherlands. Thus, I am evry clear and correct about what I say.

What is your identity? Come openly, before commenting anything, as if I insulted you.

Hello gsuhas,

I want to ley you know I feel the same as you about Guests. It is too easy to stand and talk and name any figures, when you are hiding behind the name 'guest'!

Take care....................

Please examine your motto for typographical errors.Perhaps something was lost in translation. I did not intentionally call you a fool, I was merely quoting another line from the proverb that you used in your motto, the complete proverb follows: He who knows not, and knows not that he knows not, is a fool. Shun him. He who knows not, and knows that he knows not is simple. Teach him. He who knows, and knows not that he knows, is asleep. Wake him. He who knows, and knows that he knows is wise. Follow him. Sir Richard Burton, Anonymous Arabic Proverb, Insofar as the measurement goes,you are correct in the fact that pipe diameter is a constant in a full pipe, the point I was trying to make, is that the area of the pipe is a factor needed to measure flow using velocity meters.It does not have to be calculated except when first designed, it then becomes a constant factor, and can be plugged into the algorithm that calculates flow.Most velocity type flowmeters are ordered for a specific pipe size and flowrate, so the pipe inside area is already factored in from the factory.I did not mean to imply that the area had to be constantly,dynamically calculated throughout the entire measurement process. Partially filled pipes,on the other hand, are a different matter,as well as open channel flow,using flumes, but that is a matter for another discussion. Once again, I apologize for any perceived insult, it was a poor choice of wording and timing on my part. Hope you have a nice holiday. By the way, my last name is GUEST! Why login, when It signs me automatically?

I would prefer not to discuss the acrobatics of the words you have done in justifying yourself.

Regarding you as a guest... This is again a coward way out to hide yourself.There are thousnds of guests on CR4. Be open with your prefered name, even a name GUEST, with location and other profile details. Log in can happen with whatever name you use.

A person wishing to conceal his identity can do so just as easily with a login name.Location can be falsified,as can profile, etc.Does anyone know that you are who you say you are?do you swear an oath when you set up your account?Notarized and witnessed?Recorded in legal document?Photo ID?Fingerprint?DNA Sample?Passport? You may be the greatest coward of all,hiding behind information that cannot be authenticated, and may in fact, be false. As Snoopy the famous beagle from Peanuts once said: "On the internet,no one has to know you are a dog." You obviously do not have the vocabulary or knowledge to defend your position intelligently,or to respond maturely, so you resort to a feeble sophomoric attempt at insult. Come back when you grow up. -------------------------------------------------------------------------------------------------------------------------------------------------------------------- MR GUEST

Hello Guest,

If you are on CR4 to help, why don't you instead of shouting at people.

You have a serious attitude problem, and no one will correspond with you when you put forward rudeness and almost hate. It makes no sense.

In regard to gsuhas, you do not know him. gsuhas is a very knowledgeable person.

You proved you can turn your mind round to answer the question I asked, but still the rudeness and nasty remarks as you 'say good bye'. Quote "SIGNED: Guest,AKA: coward,chicken, etc.Whutever"

You have tried to say sorry. Accept it as said that your apology is not accepted by gsuhas. That's life right.

If you put as much thought into your correspondence between people and members at that, as you did in answering my 'test' question to you.........

If you carry on like this, and do not sign in if you have a membership I will personally report you.

What super sensitive people.Any perceived insult was aimed at myself,to simply illustrate the point that it does not matter what you call me.No insult was hurled,aimed,punted,hinted,or otherwise directed to anyone else.I thought it would be perceived as humorous, but humor varies from culture to culture.My humor may be slightly abrasive to some, but there is no malice in it.I just play roughly.I expect the same in return,it's all in the game,but no one is supposed to get truly offended.I realize everyone does not have a thick skin,and for that I advise a class on de-sensitivity training.Perhaps Marine Basic Training.It is a rough world we live in, and thin skinned people have a rough time of it. I will attempt to be more genteel in the future.If you will analyze the posts, you will find that I did not draw first blood.I was intending to be helpful,and point out a typo error,and to give the complete parable from which it was excerpted. Inasmuch as the maturity level of this blog is so young, I will exit and return in a few years when it has matured.Or not.

Hello Guest,

I and all on CR4 are here to help, and sometimes to joke with each other. But, if you are not sure of how your words will be understood, use the 'Emoticon'.

Not everyone is 'English' or has a good understanding of it. Sometimes, even the 'English' have trouble understanding so this is not a 'race' thing.

Some people like gsuhas and all the 'regulars' on here are 'so into searching for a solution to the question, which can often mean working hard searching and working things out at home (if that is where they are) and, to suddenly be faced with a sentence or paragraph on something which is not exactly 'on topic', can be a shock.

If someone takes offence, just say I meant it 'this way', apologise, and leave it that. In time you may well talk to that person again, but the first time you 'spoke' to 'him', you have no idea what kind of pressure 'he/she/they' might have had on their shoulders?

I will tell you the first time I answered a question I got 12 negative 'opinions' before someone stepped in and said, "Hey wait a minute, come on he sounds honest, lets try and discuss this and help with his problem"/.........etc"

I know that gsuhas is a very well educated person and a very good engineer. As sometimes is found, someone with their 'head in a book' (for want of a better phrase), will not immediately grasp what you are trying to say, and also remember they are at least 'Bi-lingual', which adds to the difficulty understand a post or question.

By the way, I was not being vindictive in any way. But there was three or four posts which took people minds away from answering the complicated question which was posed some days ago now. gsuhas and I, as well as a lot of others helped with advice when the question was first asked, and, it has been a week or so since the OP (Original Poster) had been in touch, we had to recall and refresh ourselves as to what was wanted.

I really do thank you for your explanation in both posts you sent to answer my query. I to have been working on this and could not work out how the max' flow could be worked out when and if the flow speed was not known. You have helped me. Thank you!

It seems to me you have a knowledge and understanding on Engineering, and I am sure, if you stay around, (registered or not) you would be a great help to people asking for help on the subjects which you are familiar with. And, as, like me, you may not be 'expert', you will learn to be!

Please do not take offence. But accept things as they are. You may be talking to someone in England in English...........But it is more than likely you will be talking to someone who's native tongue may be Chinese, Australian, Dutch, Indian, Brazilian.........any language, OK?

Take care..............

I have already expressed my apologies in post 42.

Now, better I decide not to respond to any Guest (as I will never now if this is BM Guest or some other guest) unless the point is purely technical.

Sorry again.

Hello Guest,

can you work out the flow of a 10" sewer pipe, or work it out with your algorithm for me please?

I have been trying to work it out for weeks. You sound a clever person. I would be most grateful.

Take care..............

OK...A 10 inch Inside Diameter Pipe has an area of 78.5 square inches.A square foot is 144 square inches,so the pipe is 54.5 percent of a square foot in area.An approximate rule of thumb for this pipe would be 55 percent,or a little over half of a square foot.At a velocity of 10 feet per second,then 5.5 cu. feet of material per second will pass through this pipe. A cubic foot is 12 cubed, or 1728 cubic inches, and a gallon is 232 cubic inches,so a cubic foot is equal to approximately 7.5 gallons. So, 5.5 (Cubic feet per second) times 7.5 (gallons) equals 41.25 gallons per second, times 60 equals 2475 Gallons Per minute, approximately. This is an off the top of the head estimate, but I think you get the idea of how to plug in any numbers you like for the variables. Hope this helps. SIGNED: Guest,AKA: coward,chicken, etc.Whutever

Hello Guest,

I thank you. The explanation has helped very much. I was confused on how to convert and work out the total through-put the pipe can manage.

Thank you once again...........

You are most welcome.Remember, when you double the diameter, you square the area of a circle,or pipe.Think of it this way:Imagine a square 4 inches on each side.Divide the square into 1 inch squares.It will hold exactly 16 squares.Now double the square to 8 inches on each side.It will now hold 64 squares of 1 inch size. Very similar as in circles, remembering you must square the radius to get area. So you cannot add 2ea 10 inch pipes to get one 20 inch equivalent, it will require 4ea. 10 inch pipes to equal 1 20 inch pipe. Hope this clarifies things a bit when you use other size pipes for comparison purposes. ----------------------------------------------------------------------------------signed: Mr Guest

Contact your local ABB instruments rep or have a look at heir web site www02.abb.com. We used their Magflow meteres for iron sands sewage and water with very good results they are pretty bullet proof and acurate but not cheap.

I will get an I D measurement for GSUHAS monday.

Babybear--I will go back through the links again and I will get the manufacturer of what we have.

I replaced the niehbors floor this weekend and had company--Never enough time. I will have a long day tomorrow, but I will try to put some time in here soon.

Hello Kilgore Trout:

certainly sounds like you are not afraid of work!

OK with regard to you telling me the maker. No rush.

Take care..............

I didn't--I don't want to look like I am playing favorites, but I managed to put a tape on the pipe for GSUHAS and the I.D. is 17"--18" overall with 1/2" of steel and rubber--

We are busy with a bunch of big projects and I will get the manufacturer of the meter to you. Thanks Babybear.

Hello Kilgore Trout:

Not quite sure what you mean by 'favourites'? This is just a discussion and it is to help you get whatever you think is best for your application. Thats all. I mean I will never ever talk to you again!

Thanks Kilgore for the post.........K?

Do you have a source near you for whatever type of measure you decide? Is that pipe under pressure, because it seems pretty thick at 12.5 mm?

Take care.

Hi Kilgore

Thanks

1. As I understand, though the pipe in of nominal size 18", the ID of the lining is 17". Am I correct.

2. I need flow rate range, you are expecting.

With this data, I can define the flow meter size.

I await.

Gotta go--just a quick one.

17" I D and 18" O D--correct. 30,000 cu. ft. per minute(I will have to check that) with water and less with sand--

Thanks BB and GSU.

Hello Kilgore

Thanks for information.

The flow seems to be too high. The area of cross section of 17" ID becomes 1.57625 ft^2. And flow rate is 30000 cu.ft per minute.... 500 cu.ft per second. Thus the velocity in the pipe is 500/1.57625 = 317 ft/sec. Too high. With sand in water, the rubber lining should erode very fast.

Are the figures correct?

Or Am I wrong smewhere in calculations?

Hello gsuhas:

I have just read the whole post again. It sounds like a really interesting job you have. I like any large machines, anything to do with them? I think Dredgers are taken for granted. They do such a hard job.

With regard to the Pipe ID 17". r 8.5" x 8.5"= 72² x 3.1416 = 227² = 1.576² ft.

I have written this so you can see my math. It works out the same as yours.

I found a site which lists a chart you may like to view it.

I used the 3", 4", and 10" and added the sizes together to get a total.

The chart is in gpm, but if you need to convert from cfm to gpm x448.8.

I do not use these equations everyday. But going on only the far right-hand row of figures. The Maximum Velocity it seems is 18fps/5500 US Gallons ? Does that figure make sense to you? I am trying to find an answer, and the flow rate given to you just seems way to high, even for the size of pipe.

Does that figure look more realistic than the 30000 cfm? Because that total would be 13464000 Gals per Minute!

Please let me know what you think. I tried but could not remember how to figure the flow rate so had to use this chart.

Take care, and will catch up with you later.

Hello Babybear

Mathematics is very simple. You (and I) calculated the cross sectional area as 1.576 ft^2.

Flow is 30000 Ft^3/minute = 30000/60 ft^3/sec. = 500 ft^3/sec.

Velocity is simply flow (ft^3/sec)/ CS Area ft^2 = 500/1.576 = 317 ft/sec.

As you say, it is too high for the pipe. The frictional losses will be too high, thus the pressure drop.

Normally for any flow meter for liquids maximum velocity used is upto 40 ft/sec. (about 11 m/s).

I am not sure conversion between US GPM and cu.ft./min. But in your table for 10" pipe at 12 ft/sec. flow rate comes to 392.7 cu. ft.per min.

Dredger is very interesting application. They dredge the material from see bottom, collect it in huge tanks and dump it in deep sea. The dredged material contains sand and boulders up to size 1 ft. (The pump suction strainer holes are of size 1ft X 1 ft.)

These boulders and sand is pumped at a high velocity of 10 m/sec. This wears out the pipes and lining very fast. Thus normally flow meters are lined with 25 to 50 mm of hard polyurathene, which has very good wear properties.

The billing between dredging company and the port depends upon the weight of dredged material. Thus they use maximum permisible pumping velocities using couple of pumps around 3000 HP simulteneously. The weight of the only dredged material is calculated with a mathematical formulae, wher density of the flowing material is also measured and used in formulae. Daily hiring charges of a dredger may be beyond $100000 depending upon the size of the dredger.

Hello gsuhas,

I hope you are fine?

I am writing to say thank you for the post on the Maths and the other details. Very interesting!

I worked out the area and it did come to the same result as you-for the area only, well, give or take a few decimal points.

I could not figure where you got the 30,000 CFM? Then, after checking the posts I realised Kilgore Trout had given that info' in a post.

Sorry I did not reply sooner. I found a site which gives pipe sizes and nominal flow rates. But the flows vary tremendously. I worked on those examples, and came up with some really high flows and some very small flows. Then I had a brain-wave, to add together the three pipe sizes, (which was wrong!!!!!) and just copied and added them together for the total. I should have figured out the flow rates or flow possibilities, but did not. My mistake.

What I do not understand is how you can work out the flow knowing only the size of the pipe? Because that is what I at first thought you did. I realise now you were told the flow rates.

But, hypothetically, how can you work out the min and max flow rates of this 17" pipe?

Let me say here. I am sorry for my crude 'written' Math symbols.

I was ill as a child and because I was hardly at school I was not able to learn any of the more complicated math notation. It always seemed the Lowest class which I was in, has really bad Teachers. For two years, one Teacher taught us the same things 6 times over. I was so angry I almost left school.

Take care...........

I missed your point. If I understood it correctly, to make a diameter of 17", you added 10" , 4" and 3".

No, you can not do like it. The total area of these 3 pipes will only 0.6818 ft^2 as against the area of 17" pipe = 1.57625 ft^2.

Thus at 5.4 m/sec in 17" pipe flow will be 1702.35 cu. ft. per min. = 12734.46 US GPM (I found out the conversion)... This is much more than 5500 US GPM.

Hello gsuhas,

OK, back to the drawing board then? Sorry, I should have double checked the totals were the same as with the 17" pipe.

I am going to bed now so will catch up with you later.

Thank you for the post, and, yes you did understand my post thank you. I worked out the area which was the same as your answer. But I have forgoten how to work out flow rate from that. Though, I am not sure I need to know the area to figure the flow? The last and onlt time I had to do this kind of thing was thirty years ago. I just forgot.

See you later.

Take care............

Hello Kilgore Trout:

Me thinks 'Big Brother' is watching!

Both types of Flow-Meter were on the daily news sheet.

Ultrasonic Flow Meters...

Learn More | The Engineering Web®

| Suppliers/Specs

...use sound frequencies to determine flow rates; they do not work well with liquids with suspended solids or air gaps.

Subscribe to these GlobalSpec DirectU2 e-Newsletters: Hydraulics; Plant & Facilities Engineering; Sensors & Switches; and Industrial Processing Equipment.

Take care...............

Here you go Babybear--DYNASONIC series DFXD

Too busy with other stuff to dedicate to this--I am traveling for our Thanksgiving day so I will see if I can find a computer and catch up.

Gobble, Gobble.

Hello Kilgore Trout:

Here you go Babybear--DYNASONIC series DFXD

I thank you, and have a great time!

Take care.................

I have been consumed by other projects.

The vendor supplying the sensors have been out and failed to get them to work--I will leave it to them to resolve for now. I have faith that they will find out what the problem is and resolve it. I will monitor how it goes and report back to you, gsuhas and Baby bear. I appreciate your input.

I consider guests negative comments with a grain of salt--The worst you could do to them is to never respond to their comments and talk around them. Rise above it, gentlemen, they don't count.

CHEERS!

Good, you are back.

I hope you have resolved the your need for flow meter. Still I am curious to know the flow rate in 17" pipe. The flow seems too high. Is it right?

I am always there for whatever I can do for you.

I will have a busy day tomorrow, but I will try to get it. I am not sure about the information I gave you about it.

Thanks and kind regards.

Hello Mr Kilgore Trout:,

welcome back...............

29 cu. ft./min. gsuhas.

cheers! K T

Hello KT,

I copied these figures converted from your 29 ft³ pm.......Ft³ < > GPM ETC

Have you sorted a measuring device yet?

Take care...........

Hello KT,

With regard to my last post, I only included part of what i copied. Here is the rest in UK and US measures. Hope it OK. Gsuhas (Not sure of the spelling sorry my friend) is helping with the more technical detail, yes?

Forgot to send last time.

Take care...............