Turbine tower

[SmoggyTurnip]

Hi - I am new to this forum and I am not a welder.
I have built a wind turbine and now I want to build a tower for it.
I want it to be 100 ft high.
I have 10" OD X .134 wall thickness pipe in 20 ft lengths.
My question is what is the best way to join thes pipes.

1) Weld the pipes end to end.
2) Weld square plates to the ends (say 12" X 12") - drill holes and bolt together.
3) Make a coupler to go around the pipes (a sleve of some sort).

[unkle spike]

My suggestion would be to insert a stub piece inside it, and plug weld it through a hole in the outside tube.


My opinion though. I am sure more will follow

[trial&error]

i'm not going to comment on the how, but a 100ft tower will require an obstruction light a permit and an engineer's approval. anything you put up without it will subject you to many different local, state, and federal laws you may not be prepared for. I would recommend that you check with your county officials for permit and approval proceedures.

[whateg0]

Just wondering, how are you planning on keeping a tower of that height upright on a 10" diameter pole? Depending on how long the turbine blades are, you may have a fairly long part of the tower that will depend entirely on the tubing's strength. I don't think it would take much wind to topple it.

Here's a couple of pics from a windfarm about 50 miles east of Wichita. The small light-colored thing at the bottom of the second pic is a small step leading to a man-door. The blades are approximately 80' long. Pretty cool.

Dave

[SmoggyTurnip]

Nice pics, thanks for taking the time.
The blades for my turbine are not that big. I am not planning on powering a small city. My blades will be 20 feet in diameter and the tower will be supported by guy wires.

[coalsmoke]

If I were going to do this, of course check with permits, building codes, etc. Then I'd bring in a rotary well driller to push 40' of this 10" pipe into the ground and then fill the bottom 30 feet with concrete and excavate around the top of the pipe and pour another 10 yards of concrete for lateral ballast around the pipe. At least this would be my plan I'd take to the engineer for sign-off, what changes he / she would make to he plans I wouldn't know. I think I'd just weld beveled butt welds. In one of my past engineering classes we looked at how stiffeners added in sections to lateral beams could weaken the overall structure. I would imagine (but not guarantee) that this principle follows with solitary vertical members too. Example, think of a fly rod, it’ll bend and remain strong, but stiffen one section of it and bend on either end and you will eventually get a break. Now, a PEng might be use something like a continuous parameter model and tell you that since its only 110' in length (don't forget 10" in the ground without the concrete), the overall deviation (or 'flexing') is not enough to arise concern. This is just one example of why you get a certified PEng. You also may have to get your site location soil-sampled, core-sampled or possibly submitted to an ultra-sound to make sure there are no hidden sub-terrain surprises waiting for you. Keep in mind that this pipe you are using, while thin wall, is still 15.15lbs/L.foot. which means if you build this as I suggested with some form of concrete ballast and a counterweight at terrain level, you'll be in the area of 45,000lbs. The next concern I have is that intuitively I wouldn't think .134" wall pipe to be thick enough. Is this an engineered spec on the pipe or manufacturer spec'd? Does it involve wind drag? Keep in mind this thing will be like a sail once you get it fully assembled, so if this pipe dimensions is something you came across in a good deal vs. something spec'd in a certified design, I would pay careful consideration to it. This isn't everything, and please don't think this is certified or even "the right way" of doing this project. I just want to shed light on what might be a few overlooked variables and design considerations. Good luck on your project and I'd love to see some pictures

[boilerman]

why not contact some companies ...alot well sell old towers for cheap ...they will be down but you have to move them ...here is a bad shot of one we put up for a generator..and a pic of the top on the ground being fitted with a platform

[hankj]

When they built the support towers in the Altamont Pass in northern California nearly 30 year ago, there was no structural material on site that was .134 thick! Of course, there were no baby wind machines out there, either!

For what you want to do, you need to have some engineering expertise, either your own or from a consuting engineer. A 10" tube with a .134 wall at 100' high would scare the **** outta me if it could hit my joint! I'd expect that the guying material would cost nearly as much as the tube to make that arrangement safe for moderate wind loading, but you ain't hearin' from no engineer here, just an old hand who has worked on a lot of antenna towers.

Hank

[spuddown]

The pipe seems a little light to me but to make a strong weld on it I would bevel both ends and use a backer ring made out of 3/16 or 1/4 X 1" and leave an1/8" gap between the pipe.

[Mike W]

Add a little strength for ice loading.

[coalsmoke]

leave it to Mike Good point and picture though

[Broccoli1]

Originally Posted by Mike W

Add a little strength for ice loading.

Probably used a couple of clamps when weldin' it up too

[whateg0]

Something of interest while visiting the wind farm in Beaumont, KS. Don't know what caused this, but one of the turbines had a damaged (missing) blade. You can see the remnants on the ground to the right. I wonder what makes up one of these blades. There seems to be a flexible something in the middle of the blade sheathed by some rigid composite skin. Anyway, your tower needs to be able to withstand the unbalance of something like this should it happen when the turbine is spinning.

Dave

[SmoggyTurnip]

Originally Posted by coalsmoke

I'd bring in a rotary well driller to push 40' of this 10" pipe into the ground and then fill the bottom 30 feet with concrete and excavate around the top of the pipe and pour another 10 yards of concrete for lateral ballast around the pipe.

This would add 40ft of pipe to the cost = $1200
Extra concrete 30 yds at $180 per yard = $5400
Drilling a 40 ft hole $500 (guess)

The top 100 ft would still have to be guyed because it is not strong enough to take the load.

Extra cost = $7100
Extra benifit = 0

hmmm....

Originally Posted by coalsmoke

Keep in mind that this pipe you are using, while thin wall, is still 15.15lbs/L.foot. which means if you build this as I suggested with some form of concrete ballast and a counterweight at terrain level, you'll be in the area of 45,000lbs. The next concern I have is that intuitively I wouldn't think .134" wall pipe to be thick enough. Is this an engineered spec on the pipe or manufacturer spec'd? Does it involve wind drag? Keep in mind this thing will be like a sail once you get it fully assembled, so if this pipe dimensions is something you came across in a good deal vs. something spec'd in a certified design, I would pay careful consideration to it. This isn't everything, and please don't think this is certified or even "the right way" of doing this project. I just want to shed light on what might be a few overlooked variables and design considerations. Good luck on your project and I'd love to see some pictures

I did have a PE look at this. And he did model it as a continous pipe. There is no way it
would survive the wind load without guy wires. It would have no trouble when it has guy wires attached to it. No need for massive amounts of concrete. My only concern is with the welding.

[TRG-42]

If you are joining idealy you want 100% penetration

The least time consuming way but requires far more operator skill is to weld and open root ( as if the pipe was a pressure pipeline )

Gap 1/16 w/ a slight ( up to 1/16 ) land and go in with a 3/32 E6010 like Fleetweld 5P+ on a vertical down to put in the root. 2nd pass with E6010 or other electrode . If you want to use a low hydrogen you will need the special low hydrogen vertical down

Another alternative if you have a good MIG machine is to run a MIG in the open root, for your root pass


The easiest as far as welder requirements is run a backing ring ( 1/4" thick will be plenty ). Open the gap up a bit to 1/8 and with a bevel and let her have it with a E6010 . IF you want to run a more conventional stick electrode such as a standard E7018 , or a gas shielded flux cored you should run these in a vertical up progression

IF you have access to rollers it would be much easier to weld

If I had to do this job I would get rollers to rotate the pipe and use the backing ring method and use a gas shielded flux cored electrode ( E71T-1/11 ).

Good luck with your project