Spear nozzle buy or build revisited

[cricker]

Hello again,

I put this post where no one might see it so I'm, re posting here, please forgive my repeat.

I went ahead and tried the solenoid valve method, and it did save me from having to make so many trips to the genny for nozzle changes. I used automatic sprinkler valves from the hardware store, two different brands. It was some progress, but it surges the penstock quite a bit during closing, the mechanism clogs very easy thereby not always closing and they don't always open fully. Also there is more pressure drop across the valves, thus lowering the jet pressure and so the electrical output it less than a jet without a sol valve. They also use 10 watts each, so I don't want to use very many of them. They also do require nozzle changes now that the seasonal water flow is rising. It just seems like a crude way to do the job.

 I still want to try a needle nozzle. And I would like to develop this into a product since I can't find any for sale anywhere in the size range equivalent to jets of .100 to .375 inches. I think there may be a need for them, I have read a few posts on the yahoo micro hydro web site from folks wanting one. The idea would be to construct an automatically adjustable needle valve using 2 inch stainless steel pipe for the body, a threaded collar containing the nozzle portion on the delivery end and a fixed needle mounted inside. Then by rotating the nozzle collar the distance between the needle and the orifice can be accurately adjusted. Rotating automatically would require some kind of gearmotor and perhaps a small chain or toothed (timing) belt. Then a simple control system to power the gearmotor to open or close the valve as required to maintain a full forebay. Thats my simplest explanation.

 I'll see if I can learn how to post some pictures of my little "cricker hydro" which is today operating at an average of 200 watts. The solenoid valves currently in use allow a range of 0 to 280 watts. The genny/turbine with the 36 Hartvigsen bluespoons will provide up to 1000 watts when the water is high.

As always, your ideas will be appreciated.

Nando, is your offer to PM you still good?

Also, I have a Rainbow Power Company epoxy Pelton wheel I want to sell or trade for blue spoons. I bought it new from Australia for $100. USD and it is little used. It is currently mounted on a nearly new 1/2  hp ball bearing 1750 rpm single phase 110/240 volt motor in a "cricker" arrangement with a nozzle. It provided up to 300 watts at 120 volts. The turbine is somewhat noisy and not as efficient as the blue spoon turbine. I will try to post a picture of it if thats OK. I'd sell the whole unit if someone wants that. I'm not much of a salesman, I guess.

Thank you for your interest,

Cricker

[wdyasq]

I think I might consider a stepper motor for control of the nozzle. There would be several options and could be controlled with a number of methods.

Ron

[cricker]

Thanks Ron,

The stepper motor seems like a good use of newer technology. Maybe better than a DC gearmotor. I would need one with a fair bit of torque. Finding a motor and controller assembly is a big challenge for me. The only one I am familiar with is out of my dissmantled printer. Obviously it would have to be inexpensive and bombproof. Is there a source for a simple system?

Cricker

[maker of toys]

for cheap, this is a possibility:

http://www.seattlerobotics.org/guide/servohack.html

There are servos out there that are even more durable than the one demonstrated in the article.

you can get the basic servo they describe from tower hobbies for about $9.00 and shipping. <G>

most uControllers (basic stamp, PIC) have a PWM or servo control routine built into them.  if you rigged the spear (instead of the nozzle) with a gate valve type stem-and-packing arrangement, and put a 10 or 15 turn potentiometer on it with a fairly simple 8 bit ADC  (National ADC00831: http://www.national.com/pf/DC/ADC0831.html ), you could have a complete control system for about $150 in parts and less than 2 watts continuous power. . . . and you could trim that down some by only having the uController wake up every 1/2 hour or so, to look at the power demand, power output and water levels, optimize the spear setting, then shut down again.  with power only on the servo/gearmotor when the 'brain' was awake, your power consumption for such a device would be negligable.  

-Dan

[cricker]

Thank you Dan,

This is the kind of info I really need. I just have to learn and comprehend it.

The reason I wanted to rotate the nozzle instead of the spear is to avoid using a curved housing which is often used to allow the spear shaft out through the bend. Also to eliminate that long shaft and its bushing that might cause restrictions or turbulence in the water flow. A straight housing is easier to machine true, and also could have only one seal, packing or gasket system. All maintenance could then be done on the nozzle end of the housing. Minimizing the number of parts is always a goal for me. But I won't rule out any ideas for the layout. Practical simplicity usually wins.

Though I did get some formal education in electronics 20 years ago I am going to need more study to understand how to connect that controller. Your description of the controllers programming is exactly what I was hoping for. But what would the potentiometer tell the controller?

Please keep those ideas coming, I intend to share with the group whatever I end up making. I have some digital photos but how to post them still eludes me.

I really think that small steep creeks for high pressure(with no fish in them) are a part of the future of home hydropower. It is the only way I have been able to produce power from these 1.5 inch fire hoses that make one 700 foot long and one 500 foot long penstocks. I also have a half mile long fire hose that drains into a 300 gallon stock tank forebay for the 500 foot penstock. The 700 foot fire hose leads directly from a spring with a 1500 gallon storage tank. Together they can make as much as 1kw in max spring flow. Ive been tinkering with this thing for 3 years now. I keep good records.

Thank you very much,

Cricker

[Nando]

Cricker:

I do not have any PM, they are all gone.

Where are you located ?.

Why don't you connect directly with me !.

The Spear Nozzle does not need a sophisticated control, just the way to do bi-directional rotation to open or close.

One needs to determine the energy to rotate the spear and the circuit is a full bridge power controller to be able to control the direction.

Also, the Bridge is pulsed at a rate that defines that the full rotation from full On to Full OFF it will take at least 10 seconds -- this to avoid the ramming effect in the pipe.

Pulsed to avoid heating and to allow the system to stabilize.

Regards

Nando