New Farm Irrigation

[Lickey]

It seems a lot of the blue PVC piping has past its best, it has taken on a near white/pale blue colour, now, next month we will have a tractor in to clear the old papaya plantation, the pipe runs right through the middle of the plantation, its taken its toll with age and weed whackers [strimmers] ect and ive repaired it many times, my plan is to run a new pipe on the edge of the field, with outlets for irrigation, im thinking of making small trestles to rest it on, anybody tried this? does the weight of the water cause the pipe to flex to much and weaken the joints, also, anybody tried painting the pipe, to keep the sun off a bit, if so, what paint and did it work?

Has anybody seen Y section rather T section in the shops, im sure this would make the booster pumps work a little easier by creating an easy flow, I think that Ts cause back pressure cos the water is not sure where to go, where as a Y or a flowing bend rather than a right angle is easy for the water direction and the pump, Im not sure about this, but opinions and views are very welcome, Thanks, Lickey..

[JungleBiker]

It seems a lot of the blue PVC piping has past its best, it has taken on a near white/pale blue colour, now, next month we will have a tractor in to clear the old papaya plantation, the pipe runs right through the middle of the plantation, its taken its toll with age and weed whackers [strimmers] ect and ive repaired it many times, my plan is to run a new pipe on the edge of the field, with outlets for irrigation, im thinking of making small trestles to rest it on, anybody tried this? does the weight of the water cause the pipe to flex to much and weaken the joints, also, anybody tried painting the pipe, to keep the sun off a bit, if so, what paint and did it work?

Has anybody seen Y section rather T section in the shops, im sure this would make the booster pumps work a little easier by creating an easy flow, I think that Ts cause back pressure cos the water is not sure where to go, where as a Y or a flowing bend rather than a right angle is easy for the water direction and the pump, Im not sure about this, but opinions and views are very welcome, Thanks, Lickey..

Hi Lickey,

Actually the blue PVC pipe is not supposed to be used for irrigation piping, especially if it is above ground and exposed to UV light. The correct material to use is the black PE piping; it is readily available in Thailand.

About the Ys and Ts, you may be right, but irrigation systems designed by professional agricultural engineers always have Ts and Ls in the pipe layouts so it can't really be an issue.

JB.

[chownah]

Not all T's and L's are the same. Some have a restriction in the middle....some provide a smoother flow path with less irregularity. Check them out and get the good ones.

Chownah

[ozzydom]

The black poly-tubing JB refers to is available from Global Stores in sizes from 1/2 -4 inch ,it can be used above ground or buried.

It comes in rolls and is cheaper than blue piping used here but some of the fittings are a bit more exy as they are capillary type, branch lines and spinklers or drippers are a snack with poly pipe, repairs are easy as there is no glue involved..

[Lickey]

Thanks for info gentlemen,JB & Ozzy, we do have some black poly on the farm, 2inch, does the joins you mention have a blue theaded nut then a collar and a red O-ring to seal it into the joint then the on-going pipe the same? are the outlets the same set up? looks a bit exspensive to me, but on the other hand the hundred mtrs of Poly pipe has had no probs atall,its all above ground and a lot in direct sunlight, this is just joined with no outlets, Going to Udon next week so will nip into Global house and check prices, also will inspect the Ts and Ls for casting differences, Cheers, Lickey..

[mobile69]

I'm pretty sure I've seen Y-junctions in the blue pvc at Global House.

[chownah]

Going to Udon next week so will nip into Global house and check prices, also will inspect the Ts and Ls for casting differences, Cheers, Lickey..

On the issue of fittings:

There is one type of T called a "sanitary tee"....google for it and you will see how it provides a larger radius bend for the turning water in the tee....it must be installed the right way as it is not symmetric....they are expensive I think but just another option. They probably are not cost effective for your smaller lines but if you have a large high velocity line with a T used to route all flow either one way or the other then you might eventually get pay back if used there.

Also, I have seen some pump installations where the pump outlet port is 1" (for example) and the main line it feeds is 1-1/2" (for example) and the transition is made with a standard reducer fitting installed as an enlarger. Alot of energy is lost at this junction. To avoid losing this energy a long tapered fitting should be use. It should have evenly tapering sides and the length of the taper should be AT LEAST seven times the diametre of the large pipe....I think although to be sure this should be verified on the internet. Ideally the pipes should be centered at both ends of taper...a symmetrically tapering cone....but for ease of fabrication often both pipes are off to one side of the cone so that one side does not taper at all and the other side contains all the taper. My description is not so good...do you understand?

The best thing is to install the taper as near the pump as practical and before the first elbow or T...to do this for a centrifugal pump means having a straight section coming out of the pump housing for some distance while some people put an elbow right at the pump so it is important to design a pump installations so that this initial straight section can be accomodated.

Another fine point is that having an elbow near the pump inlet causes turbulance in the water and pumps lose efficiency because of this turbulance....it is better to have a straight section leading to the inlet...and if the inlet pipe is larger than the well pipe then a taper like the one I described should be used.

Also, if the black pipe fittings are expensive could you adapt a blue pvc fitting to work?...hose clamp compression bands?

Chownah

Edited December 15, 2007 by chownah

[rice555]

Hello JungleBiker and all , the company http://www.nawaplastic.com/ sales gray PVC for Ag use. I've seen there ad in several ag magazines for 5-6 years. They have "Y's" and "Large Radius EL's". For running mains, they have main/sub main crosses ie: 1"X3/4"X1"X3/4" and main/sub main reducers: 2"X1"X1-1/2X1".

I like using LDPE and HDPE for mains and sub mains, Im also using 1" HDPE for my pickup tube for my well pump. Their is a lot of different fittings to choose from. I'm going to use 1" HDPE for my mains and use 3/4" single saddle clamp to run a 25mm LDPE sub mains. Of the sub I will use TV1 valve for drip tape.

I've got some Mexican Hyb. papaya that I'm trying and for that I'm using Queen Gil drip tape and 120cm wide row cover. I got Netafim 25L/H emitters to use but now will use the tape. The price of the emitters is Bt11 and 400M of tape 1000-1200Bt. Super Products has 2, 4 & 8L/H PC-dripper that you can take apart and clean, unlike Netafim and Naan Dan. For the row crops I'm using 16mm Metzerplaz "Lin", 1.6L/H 30cm spaicing from Naan Dan in BKK off Lat Phrao Rd.

The LD & HD-PE takes 2 people to unwind the coils so they don't kink, and is good to lay in the sun a while to straighten out. To install I use a pair of PVC shears(cutter) to cut the PE, a Makita to drill holes for the saddles and and PE to tape fittings. The make spanner wrench's for all the fittings, small for 16,20 25cm. The large for the compression fittings are 20-40cm Bt.150 and 32-63 Bt.200. and a couple 6-10mm wrenches for the saddles. Always get next size opening with saddles, ie. 3/4" instead of 1/2", 1" instead of 3/4" and use a PE M/F reducer, then you can remove it if you need to go to a larger size sub, cheap for 10B.

Last, Lickey don't put anything in a water tank but water. Get a ventury fertilizer injector!

3/4 B.520, 1" B.650, 1-1/2" B.890 and 2" B.1,220. from Super Products.

[Gary A]

The black plastic pipe that comes in coils is REALLY durable even out in the sun for years. I don't know what it is made of but I have a piece my wife uses occasionally as an extension to her normal hose. I has laid on the ground in the sun for about 4 years and is still as tough as it always was. In comparison the blue pipe disintegrates after about two years if it is in the sun.