Seeking Advise On Moving Water

[Welhaven]

I'm seeking advise on how to best move water from our river up to our new 6 rai rubber tree plantation. The pipe lenght is 250 meters, and the elevation from water level to output is 14 meter. What sort of pump can handle a distance and elevation like this, and where/how should the pump be installed?

Any advise is highly appreciated. Thank you.

Welhaven in the Ubon Ratchathane Province.

[jamescollister]

Hi can't help with the pump question, but will say do the numbers carefully. I have looked at irrigation on some of my plantations and the gain from the investment is maybe one month of extra tapping per year. Extra waters is good, but will it produce enough extra rubber to warrent the expense. Don't forget that pumps break etc and have to be replaced and maintained, electricity, pipes hoses and tanks all add up. Jim

[pnustedt]

I posted about an irrigation system I installed last year:

It will certainly pump further than 250m but not sure about the height of 14m. All the equipment was purchased from Ubon Pasadon {sp.)

The system is working well and is enabling me to grow a second crop of rice at the moment.

[IsaanAussie]

Welhaven,

There are a number of existing topics that cover your questions, but to add my 2 bahts worth, I think you have two issues, the elevation and the distance. Trying to achieve both in one step will be difficult. My brother in Australia is a pump specialist and his advise to me was, whatever you do, try to pump the water once.

I would suggest that if you can elevate the water close to the river you will save energy and use a much smaller pump. This however means you will need to have an elevated storage tank from which the water flows under gravity feed. Sizing the tank depends on the volume of water you are going to need. That in turn on the irrigation system be it drip, soak or sprinkler. Here is a table of piping sizes that I made up for the gravity feed system for my pig sty. Note: No allowance for frictional losses.

Pipe sizing.xls

Another suggestion is to keep the suction side to the pump as short as possible to avoid losses.

Have a search through the site for more data.

Isaan Aussie

Edited to add data as a file, graphics lost in paste.

Edited January 19, 2011 by IsaanAussie

[OOTAI]

welhaven

As Isaanaussie says you need to keep the suction head i.e. the vertical distance the water level is below your pump, as small as possible. Most pumps struggle if they have a high suction head. Given that you need to make sure that your pump is located above the flood level so it doesn't go under each year.

To work out the size of the pump you will need you first need to work out the TOTAL energy or head needed. Each piece of pipe, each bend, each join adds energy loss to the sytem that you need to supply at the pump to get the water out the other end. So I would try and design you system to determine how many of each of these things you are going to have and then go to a supplier (or use Google) and get the energy loss for each piece. the loss will be expressed as "equivalent head loss in metres" once you have these numbers you can add them all together and get the ebergy in equivalent vertical head. You can then find a pump and ask the supplier for the "pump curve for that pump. The graph is normally vertical head on the vertical axis and flow rate (in litres) on the horizontal axis. You use your calculated number and find it on your pump curve the number of litres for that head is the the horizontal axis.

Different diamater pipe will have different energy loss equivalent metres, as will 90degree bends compared to 45 degree. If you can buy pipe in 100m rolls that is better than 4m lengths which give you 100 joins (each adds more loss of energy). If you can go with the bigeest diameter pipe you can (usually cost is the restriction). don't put a 1inch valve in a 3inch line etc etc. If you are going to irrigate with sprinklers then I would suggest having valves strategically placed so you can break it up into sections which get watered individually. That is a system that requires water for 40 sprinklers needs 4 times the water if only 10 are on at any one time hence a smaller pump because you have a smaller flow rate required.

It is not rocket science and I suggest (if you haven't already) you read past threads here on irrigation and the pinned one on Boreholes. Maisefarmer has in the past given some very detailed explanations on this subject.

Just keep posting your questios and I'm sure someone will point you in the right direction and before long you will be the forum's expert.

Good Luck

Edited January 19, 2011 by OOTAI

[drtreelove]

I'm not an expert, but I was in Sriyont CM today buying a sprayer, so I asked my guy there your question.

Good points from IA and others, Like he and OOTAI point out, better to push the water than pull it, so install your pump near the river (keeping in mind the point about flooding). He recommended a 2", 3 hp, double impeller, electric pump with a 40 m head (elevation) rating. Your distance, no problem. The brand that he had there was Italian, 'Pirali'. I bought and installed the same pump in a smaller size for a friend for landscape irrigation; it works real well. The double impeller is more powerful than the standard single. I'm sorry I forgot to ask the price, but the 1" was 5500.

If electricity to the river bank is an issue, or if you have to move the pump to and from the river on irrigation day, then you might consider a diesel motor with piston pump on wheels. Like IA, he recommended pumping into a holding tank at a high point and then irrigating from there. I took photos with my phone but don't have time to process them now. PM me if you want. don

Edited January 19, 2011 by drtreelove

[WatersEdge]

Download my Irrigation Calculator at

Type your pertinent data into the yellow cells,

and the answers will pop out precisely.

If you have further questions,

PM me with your email address.

You are halfway there.

Head is only half the equation.

You have 14 meters static head.

That gets the water there but doesn't flow it out.

Then you add hose line pressure or sprinkler pressure to it.

Flow is the other half.

How much water will be applied to 6 rai.

How many hours of the day are you willing to run?

Is this a drip system with a small pump running 24/7,

In that case you can use a much smaller pipe,

than if you want to cover the whole thing in a couple of hours a week.

When you know your acceptable flow rate in Liters per Minute

Then choose a large enough pipe that the flow velocity does not exceed 1.5 meter/second.

Above that you will suffer very high friction losses.

[Lickey]

If electricy is available, a 2 hp single vane pump at about 3000bht should do the job, from what the OP descibes, his farm is hillside same as ours, if you maths men want to work it out, it rises 3in in 1 yard, and the pipeline is about 300 mtrs long, 2in blue plastic into 1in hose for sprinklers,

The system i used with the help of Chownah was a borehole pump pumping into a ground level water tank, and the 2in booster pump operated by a luke-loy floating valve that turned on the booster pump, or off when level sunk.

I think in your case, a 2hp pump with a flexible re-inforced hose with a good magaluf [thai name] valve fitted, and the first few meters allowing movement of the pump due to high/low water would suit your needs.

If you use the blue plastic pipe, give it coat of paint, any colour, it stops the sun baking it, making it brittle ect, also fit a one way valve a metre or so from the pump, the water in the pipe will keep it cooler.

Consider fitting a timer, night time watering is far more effective without the sun evaporating the water, about 2000bht from home pro,

[IsaanAussie]

I would like to ask a question of all you irrigators out there. Do any of your fertigate at the same time? I am looking for some clues, or somone as a test source to try using worm castings, or steeped water or vermitea in irrigation water. I have had great results with drenches and foliar sprays and would like to try with irrigation. All input welcome.

Isaan Aussie

[WatersEdge]

Hi IsaanAussie,

I built a fertilizer injection system a couple years ago,

see the original post with photo at

http://www.thaivisa....21#entry3085821

which works great, dumping bags of fertilizer in,

dissolving with the pump circulating the water vigorously in the tank,

then injecting into the sprinkler mainline.

I used a 1 cubic meter plastic pallet tank,

2 inch Honda gasoline pump as recently offered for sale by DrTreeLove

Then rigging the valves so that three functions are served.

1. Pump water into the mixing tank from any source,

I used the water passing by from the irrigation mainline

2. Stir the water to dissolve the fertilizer,

pulling water from the bottom of the tank,

and pumping it back into the top,

with a flexible hose which allows you to blast the solids on the bottom of the tank

3. Injecting the fertilizer solution into the sprinkler line.

I inject a relatively small volume of concentrated fertilizer,

into a much larger volume of mainline water passing the injection pump location.

It is possible to dissolve more than five bags of fertilizer into a cubic meter of water

The solution rate is probably limited by the drop in water temperature as the fertilizer dissolves.

Depending on the fertilizer chemical compound,

the temperature of the water may either drop or increase.

but heats of solution are not in today's lesson plan.

There was a thread a few months ago in which the original question was

whether the main pump's NPSH could be used to pull fertilizer solution into the main flow.

http://www.thaivisa....25#entry3088925

The answer is Yes, as the pump doesn't distinguish the source that it's pumping from.

It will pull suction from the source of least resistance.

You can even pump an uncertain amount solids this way,

provided that they are small enough to pass through the pump impeller,

and then through the sprinkler nozzle.

Just be prepared to pull things apart if it clogs.

The Honda gasoline pump has a large impeller housing,

so it's tough to clog,

but the little house water pumps have much smaller impeller vanes

The intake screen is the key to this of course.

[customcurb]

hi all,

excellent info and much a bit above my head. <need to get something like a modest amt of water up a hill to manually water rubber trees. <hill is about 25 meters vertical from small river and 300 meters max from the river. <have a kubota 7.5 hp <iron buffalo tractor as power source. now getting accurate info in uppernowheresville from a few shops is getting silly and gettig a spec sheet isnt possible here. would a centrifuge pump rated at 30mm, 2950rpm, 7.5hp, .5 sq meter per minute (all directly off the plate on the pump) do the job... about 3500 baht cost

glennb6

[RedBullHorn]

I'm not an expert, but I was in Sriyont CM today buying a sprayer, so I asked my guy there your question.

Good points from IA and others, Like he and OOTAI point out, better to push the water than pull it, so install your pump near the river (keeping in mind the point about flooding). He recommended a 2", 3 hp, double impeller, electric pump with a 40 m head (elevation) rating. Your distance, no problem. The brand that he had there was Italian, 'Pirali'. I bought and installed the same pump in a smaller size for a friend for landscape irrigation; it works real well. The double impeller is more powerful than the standard single. I'm sorry I forgot to ask the price, but the 1" was 5500.

If electricity to the river bank is an issue, or if you have to move the pump to and from the river on irrigation day, then you might consider a diesel motor with piston pump on wheels. Like IA, he recommended pumping into a holding tank at a high point and then irrigating from there. I took photos with my phone but don't have time to process them now. PM me if you want. don

฿5500 !?!! (farang's price ? )

I bought my 1.25'' (1&1/4'') double impeller Italian Pirali for ฿3'000 6 months ago, very powerful indeed

I bought from this shop in Chiang Rai, most TV members in Chiang Rai know this shop.

http://www.thaivisa.com/forum/topic/254852-google-map-for-chiang-rai/page__view__findpost__p__3442956

Edited February 5, 2011 by RedBullHorn

[Lickey]

hi all,

excellent info and much a bit above my head. <need to get something like a modest amt of water up a hill to manually water rubber trees. <hill is about 25 meters vertical from small river and 300 meters max from the river. <have a kubota 7.5 hp <iron buffalo tractor as power source. now getting accurate info in uppernowheresville from a few shops is getting silly and gettig a spec sheet isnt possible here. would a centrifuge pump rated at 30mm, 2950rpm, 7.5hp, .5 sq meter per minute (all directly off the plate on the pump) do the job... about 3500 baht cost

glennb6

Welcome Glennb6,

I dont think a centrifuge pump would be any good for you, Thing is, a centrifuge pump usually has a head of water to start with, you know, pumping from below the water level, they can be primed to suck water, but the pipework must be very airtight, and even the pump shaft seals, I dont think you will be getting much of a pump for 3500bht to lift 25mtr,

I have a different set-up, but near the same as yours, Well, measurment wise anyway, Keep looking here, you,ll get some good advice soon,,

Cheers, Lickey.

[WatersEdge]

Hi customcurb glennb6

May I encourage you to not be intimidated by pump numbers.

It's no big deal to start with, and I've made it as easy as can possibly be.

Plug a few numbers and watch the results pop out.

We used to say The Lottery is a Tax on those with poor math skills.

Can I adapt a bit to....

Bad Pump Design is a Wealth Transfer Mode to the Fuel / Electricity Company.

I'm here to assure you that the level of "Engineering"

is so fundamental that it barely qualifies as Engineering.

Anyone who regularly pumps water,

particularly if it influences his income

cannot fail to do it right.

Energy Costs alone can make or break an entire operation.

First your conditions.

You want to lift

25 meters elevation head

300 meters distance.

Let's add 5 meters head to make it flow out the hose.

30 meters total head from River to Rubber Tree.

A centrifugal pump is above the water source.

You can pull a suction head of 6 meters,

while as little as possible is preferred.

Locate your pump as near the river as convenient,

and not more than 6 meters elevation above.

Airtight fittings on the suction line are essential.

Real life conditions force adjustments.

My pump is around 40 meters distance from the water,

and around 5 meters above low season level

It's not ideal, it's what I have to do to remain above flood water.

A foot valve is required at the intake.

I use a larger foot valve than required by the suction line pipe size,

as any flow restriction through the foot valve costs energy.

A bit of pump science here...

the perfectly efficient pump at sea level would pull 10.35 meters,

as this is Atmospheric Pressure.

It is not a perfect world, we don't have perfectly efficient pumps,

the world's finest pumps are 0.85,

with anything off the shelf in Thailand around 0.70

so work with 6 meters or less.

Back to the problem at hand...

How many trees requiring how many liters water each?

How much time would you like to spend manually watering them?

Let's make something up for the purpose of this discussion,

conveniently matching it to the Pump Spec tag.

100 trees

50 liters per tree

1 hour spent.

That's 5,000 liters per hour

100 x 50 => 5,000 liters / 1 hour => 5,000 liters per hour.

A cubic meter is 1,000 liters

So 5 m3/hr

Let's recreate that Spec tag on the pump

30 meters Head

2950 rpm

7.5 hp

5 m3/hr

There's something wrong with those figures,

because the Excel calculator mentioned in my thread above shows

Total Electric Draw 0.74kW => 0.99 hp

Here the link is again....

You will want a pulley on your iron buffalo engine that is

3 times larger diameter than the pulley on the pump.

This will enable you to idle back your 7.5 hp diesel engine,

while still achieving the 2,950 rpm on the pump.

2,950 / 3 => 983 engine rpm

Cast iron pulleys are available for around B175 - B220 in all diameters.

Changing the Pulley requires three bolts on the engine flywheel.

I use a channel iron frame to mount my engine and pump

perfectly aligned and with belts properly tensioned.

The frames cost me B2,000 at my local equipment dealer.

If you need the engine back to your tractor,

it is admittedly a bit of wrench work,

four bolts engine mount and lifting the engine here to there.

The local method is to run a long belt through open air with stakes pounded in the ground

and a rope loop twisted with a stick to provide belt tension.

To each his own...slipping misaligned belts waste energy as well as wearing the belts out.

Pipe size is an important consideration.

Note that the Excel calculator is set at 2" pipe as the smallest size.

Change that to 1 inch in cell D10, and the Friction Energy Loss leaps to 1.61 kW => 2.16 hp

while at 2" pipe is only 0.06 kW => 0.07 hp.

Note that Friction Loss can easily exceed the well designed Total Required Power

You will buy pipe once,

then pay Energy cost every time the pump starts.

For this system,

Use not less than 1.5 inch Pipe.

The Grey color Agriculture grade PVC will work fine.

Slightly above that the Blue color 5.0 bar grade is great.

5 bar is 5 x 10.35 => 52 meters / 0.70 => 74 psi pressure rated.

There isn't a stated pressure rating on the Agriculture grade,

but I'll say it will handle 30 meters head

It is a waste of money to buy 8.5 or 13.5 grade pipe.

If I've not made anything clear,

always happy to follow up.

[RedBullHorn]

For this system,

Use not less than 1.5 inch Pipe.

The Grey color Agriculture grade PVC will work fine.

Slightly above that the Blue color 5.0 bar grade is great.

5 bar is 5 x 10.35 => 52 meters / 0.70 => 74 psi pressure rated.

There isn't a stated pressure rating on the Agriculture grade,

but I'll say it will handle 30 meters head

It is a waste of money to buy 8.5 or 13.5 grade pipe.

If I've not made anything clear,

always happy to follow up.

Hi WatersEdge,

Could i impose on you to simplify this part in Layman Term, i really want to be educated on this especially on the

pipe classes...appreciate~

[WatersEdge]

Hi RedBullHorn as the lead Layman,

On PVC pipe manufactured in Thailand,

regardless which of the several manufacturers,

there is a line of print down the length of pipe.

It tells the nomimal size of the pipe in inch & mm as well.

Then it has one of three numbers,

which are the three grades called for under Thai Industrial Standard.

5.0, 8.5, and 13.5.

These numbers technically stand for the kg/cm2 pressure rating,

but the difference between kg/cm2 and bar is forgiveably small.

For those laymen more comfortable with psi than bar,

1 bar is 14.7 psi...round it to 15 and you'll be just fine

For detailed description

http://www.thaipipe....es/upvcpipe.htm

Your question is what do the ratings mean?

They are to be used for pressure up to the rating

5.0 bar 73 psi 52 meters head

8.5 bar 125 psi 88 meters

13.5 bar 198 psi 140 meters

.

Edited February 6, 2011 by WatersEdge

[RedBullHorn]

So if i were to use a class 5 with a 80 metre head, chances are the pipe might burst ?

Edited February 6, 2011 by RedBullHorn

[WatersEdge]

Hi RedBullHorn,

Yes, 80 meters head would almost certainly split 5.0 bar Pipe.

I'm naturally curious to know the results if you will do the test.

I had an unfortunate occasion once, almost twice,

but fortunately the one break occurred in a place that was easy to reach above the surface.

There is an advantage to one bad fitting somewhere in the system.

Interesting thing is that when the pressure suddenly released due to the failure,

the sudden surge in the suction line collapsed it.

A 4" pipe collapsed tightly flat and twisted is quite a sight.

[David006]

Hi can't help with the pump question, but will say do the numbers carefully. I have looked at irrigation on some of my plantations and the gain from the investment is maybe one month of extra tapping per year. Extra waters is good, but will it produce enough extra rubber to warrent the expense. Don't forget that pumps break etc and have to be replaced and maintained, electricity, pipes hoses and tanks all add up. Jim

Hey Jim good to see you again ..hope the new improved rubber prices are keeping you smiling...lol

To the OP ...last year I installed a 30m output lift pump down the hill to a second well for domestic consumption at the house at about 20-30m elevation and 180m distant from the well. The cost of the pump blue 1" piping/glue electrical cable tie wraps and an additional 1000 litre tank was under 10k baht.Plus a lot of sweat and beer of course...

It is a manual system so I just plug it in every couple of days up at the house to refill the tank as required. No idea about the additional electric costs but I have not noticed any significant increase in the bill...Our overall bill is always less than 1000 baht...three water pumps two fridges, fans, electric showers,kettle,toaster oven,lighting, TVs etc ...no air. ( I do notice a jump of two hundred baht or so when we are invaded by kids...but that's nothing compared to the food bill lol)

just a thought Jim.. a month of additional tapping could be worth a lot of moula these days..for us about 40-60k gross on our currently tapped 600+ trees..pretty good ROI even with as little as 200 trees...so might be worth the extra outlay and headaches.. ( ...yup just had to change the start up capacitor on the &lt;deleted&gt; pump)

cheers

david

Edited February 6, 2011 by David006

[customcurb]

thanks guys for the responses. let it be known that all shops and the guy drilling our well on another site are virtually clueless. more info from you guys than can be found locally. will attempt to run the spreadsheet.

glennb6

[WatersEdge]

It truly boggles the mind.

I'd dream of a thousandth share

of the energy wasted by pipeline friction in Thailand

which is around 95% avoidable

in exchange for minimal increased initial pipeline cost.

But who's greedy?

I'll settle for a ten thousandth and still be rich.

Hmmm, I'll have to work this angle a little closer!

I could boost one time sales of larger pipe,

resulting in a landfall to the pipe manufacturers.

Perhaps they'll share a 1% commission?

There are no performance curves available with pumps here either.

As customcurb mentioned, only the spec tag on the pump is available.

How do you know where the peak efficiency is?

I suppose the peak efficiency of the pump is of small concern

when so much greater energy is blown on friction.

In searching for the TIS Pipe Specs yesterday,

I chanced upon the Engineers Without Borders paper on Water Guidelines

http://ewb-usa.org/downloads/Guidelines/Water%20Guidelines_Final.pdf

It is a lot of information under one cover.

[OOTAI]

It truly boggles the mind.

"ONLY IF YOU HAVE ONE"

There are no performance curves available with pumps here either.

As customcurb mentioned, only the spec tag on the pump is available.

How do you know where the peak efficiency is?

I suppose the peak efficiency of the pump is of small concern

when so much greater energy is blown on friction.

In searching for the TIS Pipe Specs yesterday,

I chanced upon the Engineers Without Borders paper on Water Guidelines

http://ewb-usa.org/d...lines_Final.pdf

It is a lot of information under one cover.

Watersedge the guidelines are great, thanks, I am not sure what will happen when people see the equations towards the end!

As for obtaining a pump curve, if you have the pump make and model just gooogle it, that's what I did.

As for understanding peak efficency of a pump and reading the pump curves anyone can google "reading pump curves" and there are a myriad of sites to look at some do a very good job of explaining in layman's terms.

Just this week the missus has been installing some pipes for watering the garden, I insisted on 1inch pipe and she spat the dummy as we had some 1/2inch already. Why do you want to buy more? My answer "because!" I have given up trying to get her to understand the tradeoff between initial capitol spend and ongoing operating costs. I suppose I could have been nasty and asked why we had the small pipe in the first place (she over-ordered on a previous job) but thought better to leave the scene intact.

[WatersEdge]

Hi Ootai,

The friction equations toward the end aren't all that terrible.

You put them into a spreadsheet once,

and from then on out they give the results instantly.

I used Hazen-Williams friction equation in the calculator spreadsheet,

so no one needs to figure it out

All my spreadsheets are open unlocked,

after you save from download to disk,

so that anyone who wants to study the guts of it is clearly able.

Hazen-Williams does not provide the friction loss of bend fittings,

only the calculation for pipeline distance.

So if anyone ever wants to get that particular,

you will have to look up the specific values.

adding them together for the total friction.

Fitting friction values are available online, and probably in the EWB paper.

The general rule of thumb is

Do Not Exceed 1.5 meters/second Flow Velocity.

That's 5 feet per second for imperial system folks.

That's in Cell D19 of the spreadsheet.

I call 1.50 the Friction Threshhold,

because above it friction goes nuts.

If your pipeline is long drop to 1.2

If you have a lot of bends drop to 1.0

The reason I ran the comparative costs of the next larger pipe size

is so that the designer can see how many years will be required

for the energy savings to pay off the next larger pipe size.

If the number of operating hours per year are small,

then of course you should use the smaller size pipe.

If you are running nonstop, then the larger size will pay off nicely.

In general, running a small system continually is the most economical,

but not very many of us want to tend our irrigation system 24/7

An adequate design allows you to cover the entire field with 10mm water in an 8 hour day.

This allows plenty of capacity during a hot dry spell,

coinciding with peak plant water demand.

Corn, for instance, is a high water demand crop,

which peaks at 20mm per day at around 80 days.

That is an outrageous amount of water,

more than rainfall can be depended on to provide

If the plant is dry at that time, the yield will be reduced,

no matter what all else has been done properly.

If you are farming plants that start out as fragile tiny seedlings,

such as Carrot, then you absolutely need to be able to get the water out there in a hurry.

You can watch your little plants toast in the sun,

while you water as fast as you can but not quite fast enough.

For Carrot I'd allow 20mm per 8 hour day.

Not that tiny carrots need 20mm,

but the whole field needs 2 mm in a 1 hour burst.

then again two or three hours later

It is so nice to have the surplus ability

to keep the entire farm moist at all times.

We use the sprinklers as a giant aircon,

keeping the entire field as damp and cool as the baby plants require.

[RedBullHorn]

.......................................... ??????

(Rocket Science !?!!)

[WatersEdge]

No RedBullHorn as the lead Layman,

it's not Rocket Science at all.

Thanks for being the voice of exploring the mystery.

So simple that it barely qualifies as Engineering,

but so important that farm profitability depends on it

The previous post is in response to Ootai's comment

that the equations near the end of the Engineers Without Borders paper might confuse some.

Those equations are two different methods of calculating friction loss in water pipeline flow.

Mr Hazen working together with Mr. Williams developed the Equation that carries their names.

The Hazen-Williams Equation allows calculation of how much friction loss will be felt,

for a given volume of water travelling a given distance through a pipeline

That's for a straight smooth pipeline.

Let's hear a round of applause for them both.

In addition to that straight smooth flow,

friction loss also adds up at every bend and other disturbance to smooth pipeline flow.

That can be calculated with a lot more detailed work,

adding the loss from each fitting in a specific system.

To simplify it all, it is safe to say, Use Bigger Pipe!

The exercise of calculation is to refine how big the pipe needs to be.

I could tell everyone to use 12 inch pipe,

and everyone on the forum would be totally safe from friction

while for most of us, 4" mainline with 2" distribution lines is quite adequate.

The Friction Threshhold of 1.5 m/sec refers to the speed the water travels through the pipeline.

Imagine cutting a 1 meter long piece of pipe, and filling it with water.

The Volume of that water is measured by the cross sectional area of the Pipe.

The pushing that 1 meter long body of water inside the long pipeline,

faster or slower, is the Flow Velocity.

Let's take a stick of 4" Pipe for a quick example.

The Cross Sectional Area is Pi x Radius x Radius.

Let's keep this all metric, because even though I'm American,

as an Engineer I can assure you the metric system

is easier and more clear than Imperial measures.

Step by step:

4 inches x 0.0254 meter/inch = 0.1016 meter Diameter

Radius is 1/2 Diameter => 0.0508

The Area of a 4" Pipe then is Pi 3.1416 x 0.0508 x 0.0508 => 0.0081 m2 (Square Meter)

The Volume of a 1 meter length of 4 inch pipe then is the Area X Length.

0.0081 x 1 => 0.0081 m3 (Cubic Meter)

A Cubic Meter is 1,000 liters,

so moving the decimal point three places to the right

We have the Answer... 8.1 liters in a one meter length of 4 inch pipe.

Now let's calculate the Flow Volume.

This is how many liters pass through the pipeline in a minute.

Liters / minute => lpm

The Friction Threshhold of 1.5 meters/second

multiplied by the Cross Sectional Area 0.0081 m2

gives us 1.5 x 0.0081 => 0.0121 m3/sec

There are 1,000 liters per cubic meter

60 seconds per minute

0.0121m3/sec x 60 sec/min x 1000 liters/m3 => 730 liters/minute

Now bringing it all to the field.

Let's say we have 1 Rai field area.

That's 40 x 40 => 1,600 m2

Let's say we want to put on 10mm of Water per day.

10 mm converted to meter is 0.0100 meter

The Volume of Water required then is

1,600 m2 x 0.0100 m => 16 m3 => 16,000 Liters

The 4 inch Pipeline carries 730 liters per minute.

How many minutes does it take to water the field today?

16,000 liters / 730 lpm => 22 minutes

So, while it is kind of tedious,

it's not all that difficult.

It is just troublesome enough that the effort placed into building a spreadsheet calculator is well spent.

The spreadsheet goes on to bring in

the cost of electricity,

the number of hours operated per year,

the cost of pipe

the friction loss energy compared to

the unavoidable rightful energy requirement

pump efficiency loss

electric motor efficiency loss

the desired flow rate

the length of the pipeline

the elevation difference

the desired pressure at outlet

More than we can keep clear in our head,

so the spreadsheet remembers and changes it all together as called upon.

The reason that Rocket Science has become a part of our vocabulary,

is that putting a Rocket where you want it,

Let's say Landing on the Moon

while the Earth is rotating and orbiting the Sun

the Moon is rotating and orbiting the Earth

with gravitational forces of the Earth

yielding to weightless space,

then entering the gravitational force of the Moon

gets extremely complicated.

It's not like flying an airplane,

where you figure it out as you go

looking at the ground along with a map and compass,

coming in on your destination

this one has to be figured out to seconds not minutes.

No mistakes allowed, because good men are going to die

at the fingers of a bad engineer.

They shot a metal tube packed with toys from a point in Florida,

so that it landed on a chosen point on the Moon,

while everything involved is moving!

And does so gently enough to have survivors following impact.

Then if that wasn't enough,

they lifted back off, and made the safe trip home.

splashing in the water close enough to a boat,

ready to pick up the two time survivors.

Furthermore, they did it before computers were powerful.

The early work was sliderule and papers.

My laptop today has more power than all that NASA had in that day.

Ha, I just don't use what I have as intensively.

Now Those guys are Engineers!

What I do is by comparison is child's play.

One point I'd like to close with.

The goal here is not to be confused by the calculations

or for me to amaze or irritate anyone because I'm quite comfortable with it.

Just as the goal of the Moon Landing was not to accumulate stacks of papers with lots of numbers written.

Our small goal is to keep money in our pockets,

which otherwise will be spent on diesel or electricity.

As I said starting off,

Bad Pump Design is a Wealth Transfer Mode to the Fuel / Electricity Company.

It's MONEY...and the only track to keeping that money is to understand.

If anyone is up for subsidizing the continued success of big energy,

be my guest

but proceed alone.

[RedBullHorn]

Thank you WatersEdge,

Your last post is save to the disk ...

Sorry for pulling you down to my level

RBH

[OOTAI]

Thank you WatersEdge,

Your last post is save to the disk ...

Sorry for pulling you down to my level

RBH

RBH don't apologise to him as I reckon he's not really an Engineer. Engineer's are not meant to be very good with words and I loved that last post of his, especially the bit about how the yanks still insist in maintaining the imperial measurement system and then proceeded to go metric.

Watersedge I congratulate you that was one of the most humourous posts I have read.

Now in all seriousness I have a question for you. In the pdf file from engineers without borders they provided some factors for de-rating the pipes in regard to temperatures. Do you have any experince in this regard of do you bury your pipelines. I was amazed that at 38 degrees they suggest you de-rate the pipe by a factor of 0.61. If you did that then a 8bar rated pipe would be rated less than 5bar.

[WatersEdge]

Hi RedBullHorn

Glad you are satisfied.

The comparative levels are narrowly separated,

and with this yours is brought up.

I don't agree that there is no such thing as a stupid question,

but the guy asking the question even if it was at first stupid

is out far ahead of the others who didn't ask.

Please...that's a general statement...I don't mean to say your questions were stupid.

I'll have to continue learning to stay ahead of you.

Continued learning is the quest that lasts a lifetime.

If I stop wanting to know it's time to quit.

I read stuff that smart people write,

stay completely buried below their level,

and what do you know, it generally sinks in.

Guys like Hazen and Williams for example,

they did the work, we just plug and play their numbers.

From the Student's perspective

That "glazed faraway stare" is what we want to avoid.

Those who don't want to learn are totally safe.

Brain Pain is always a good thing.

From the Teacher's perspective

Einstein said, If you can't explain it to a six year old,

then you don't know it yourself.

I'm off to explain friction to my son.

Hi OOTAI,

I bury all pipe.

Mainlines 1 meter deep

Distribution lines initially were 0.30 m,

but all new construction will be 0.50 m

because tall 2" sprinkler risers are self supported by the dirt.

Yes, I made some errors in the beginning...which is why we have saws and glue.

Yes, it's overkill, but I don't want a plow or a hoe to break it,

and it makes it too much work should a thief every want my pipe more than I.

Simon Bird, a Brit Civil Engineer in Chiang Mai said that 0.30 m dirt cover

is sufficient for a car to drive over without damage.

If EWB says PVC at 38C derates to 0.61 then let's run with it.

For the open sunlight hot pipe

as soon as water flows inside it will begin to cool.

PVC is a lousy heat conductor / fabulous insulator,

so it will take time for even a thin wall pipe to cool from inside out.

A pipe sitting in the sun full of water will not become as hot as an empty pipe.