[SEL] O.T. O.T. Need Help On Water Flow Problem
curt at rustyiron.com
curt at rustyiron.com
Fri Jun 5 05:19:23 PDT 2009
You can tell someone who has never lived in the south! Until this year we
have been in drought for 5 years. The last few summers there have been
month long stretches with NO rain at all.
Mother Nature is making it up to us this spring/summer!
Lake Hartwell is still down about 15'.
Curt
> I just LOVE the TOTAL BS of this thread. I plant about 5-6 doz. tomato
> plants each year and have NEVER given any thought to watering them--
> that's what rain is for. I would think I get 30-40 bu. a year and give
> the vast majority away.
> Dave
> PS, I do hope this thread continues. Jennie says I easier to get along
> with when I laugh so hard that my sides hurt every evening!
> PPS, doG save us from "Greenie Magazines!"
> PPPS, Paul, I pretty sure you can get a stimulus grant from POTUS for
> this project!
>
> On Jun 4, 2009, at 3:41 PM, Jerry Evans wrote:
>
>> At 06:00 PM 04/06/2009, you wrote:
>>> Date: Wed, 3 Jun 2009 12:50:27 -0500
>>> From: "Elden DuRand" <edurand at mchsi.com>
>>> Subject: Re: [SEL] O.T. O.T. Need Help On Water Flow Problem
>>> Paul:
>>> I think what I'd do would be to use the PVC pipe as a manifold to
>>> which I
>>> would attach a number of irrigation drip heads.
>>>
>>> Go to a big box store and look at the Rainbird and other systems.
>>> You can
>>> get drip heads that can be used with 1/2" NPT (I think) PVC nipples
>>> which,
>>> in turn, are screwed into 1/2" NPT holes in the manifold.
>>> They are adjustable so you can balance the system close enough for
>>> Mother
>>> Nature.
>>> What, me engineer??!!
>>> Take care - Elden
>>> http://www.oldengine.org/members/durand
>>
>> Hi Paul,
>> I'm getting into this thread a bit late but have been
>> following
>> it. It would appear that you are following plans from some "Greenie
>> Magazine" :-) - have the Tomato plants read the same article ?
>> I liked Ron Carolls answer as well as many others.
>> If I remember correctly (I'm not going to read all the replies
>> again) you have 2 main pipes going down the length (which is not
>> very long)
>> and they are closed on the ends.
>>
>> This is what I would do:
>>
>> 1) I would use a slightly bigger pipe for these lengthwise
>> pipes
>> (lets just say 3/4") (it reduces friction and increases volume) (I
>> also
>> think that at the volume/pressure you are using that this will not
>> make any
>> appreciable difference to the tomato plants) and I would NOT have them
>> closed at the end - I would join them (maybe with another piece of
>> the same
>> size pipe) which would in effect give you a "circuit" ie. (with no
>> holes
>> yet) the pressure would be equal throughout the circuit.
>> 2) Then drill your holes (but I prefer the adjustable microjet
>> nozzles or Ron Carrol's idea using screws and washers). When
>> deciding on
>> the size holes (assuming you are NOT using aforementioned adjustable
>> microjet nozzles) you should drill go for something like this.
>> i) The "area" of the inlet pipe. (I'm going to change to
>> metric
>> here - it's easier for me to work out but the principle is exactly the
>> same.) 3/4" inch pipe is (as near as dammit) 19mm pipe. (I'm also
>> going to
>> use this as an internal measurement for the sake of not letting this
>> turn
>> into an encyclopaedia).
>> The mathematical formula for working out the "area" of a
>> circle is
>> "pi" X radius squared) (I do not know how to write this correctly on
>> my
>> keyboard).
>> Now I'll try to explain this as easily as possible
>> (apologies to
>> all others for this "long winded explanation").
>> To all you guys who understand these things I do apologise
>> but I'm
>> gonna try to explain this thing in a way that someone who does not
>> understand will get the picture.
>> "pi" is a mathematical formula described by some ancient
>> Greek -
>> you do not need to know how he arrived at it - just use it. Roughly
>> it is
>> (22 divided by seven) or "the answer" (3.1428571)
>> Your 19mm pipe has an internal diameter of 19mm (surprise).
>> So the
>> "area" of this opening is ("pi" X (times) the radius) (if the
>> diameter is
>> 19 mm then the radius is half of that or 9.5 mm
>> This equals pi (22 divided by seven) or 3.1428571)
>> multiplied by
>> the radius of the 19mm pipe
>> 3.1428571 x 9.5(the radius - or 1/2 of the diameter of the
>> pipe)
>> equals 29.857 (unless my cheap Taiwanese calculator is lying to me).
>> This
>> is the delivery area of your pipe. 29.857
>> Now divide this by the number of "delivery points" that you
>> need.
>> In your case you mentioned 16 (tomato plants). So divide the answer
>> above
>> by 16 - ie. 29.857 divided by 16 = 1.8660625. and this will give you
>> your
>> answer for the area of the holes you need. Now you need to convert
>> this
>> "area" back to a diameter (so you know what size drill to use). Now,
>> for
>> tonight, I've forgotten the formula needed here so I will use
>> "Google" (to
>> work out the "diameter of a circle" from the area").
>> This gave me an answer of "1.5414099285872527" - If "Google"
>> was
>> correct then you need to drill all your holes "1.5 mm".
>> What I would do is to drill these holes approximately half
>> of this
>> size and put a bucket under any one of the holes and measure how
>> long it
>> takes to provide your required amount of water (always trying to
>> bear in
>> mind that the tomato plants have read the same article.) It's more
>> accurate
>> to have "half size" holes and leave the tap (faucet) open for twice
>> as long.
>> Sometimes "maths" or "science" can baffle us all - have the
>> tomato
>> plants also read this article?
>> Now, the above method will only work if your delivery (where
>> the
>> water comes from) pressure is always exactly the same. Do you really
>> think
>> that the tomato plants give a damn?
>>
>> Understand that this answer will only be relevant if your water
>> pressure is
>> always exactly the same ie. "all things being equal".
>>
>> Paul, I've been there, done that and bought the "t"shirt.
>> Fresh
>> "homegrown" veggies are really great and they are also "so green".
>> But, at
>> the end of the day, they will always cost you more than you can buy
>> them
>> for at the local vegetable shop. The reason is that you will grow
>> veggies
>> "in season" at the same time as the "big producers" put theirs on the
>> market. Unless you are planning to produce "out of season" (which
>> involves
>> major investment in greenhouses and similar) you will not win
>> financially.
>> Just my opinion. Be prepared to have that "They came from my
>> garden" expression cost you Bucks.
>> Jerry
>>
>> Keep the revs up (or down)
>> Jerry Evans
>> Near Johannesburg in Sunny South Africa.
>> Etched Brass Engine Plates made to order:
>> <www.oldengine.org/members/evans/plates/index.htm>
>>
>>
>>
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