[SEL] O.T. O.T. Need Help On Water Flow Problem

Thu Jun 4 14:08:28 PDT 2009

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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