Pelton/Turgo Needle valve nozzle, to buy or build

[cricker]

Hi everyone.

I've searched the web many times and read (and learned) a bunch about AE, and have built a dandy little hydro plant that harvests from 100 to 900 wats of electricity at a max of 73% eff. It uses fire hoses for the penstock at 200 feet static head and a 2 hp single phase induction motor. It uses 36 Hartvigsen bluespoons on a hub that I've made and Rainbow Power nozzles that while efficient, have to be changed quite often due to ever changing water flows. Its been running now for 3 years with a two nozzle setup.

I have looked for small or should I say tiny, adjustable needle nozzles (spear valve)on the web but have only found photos of large ones and no specifics on how they should be constructed. I would like to build or buy one that can be made to automatically adjust to keep the forebay full at all times, regardless of flow. Contolling the nozzle shouldn't be too difficult, but I very much need specifics on how to make the nozzle itself, at the business end, so to speak. I would buy one but haven't seen any in that size range. Th nozzle diameters I now use range from .050 to .390. Any help or links you folks can provide will be most appreciated.

Regards,

Cricker

[Nando]

Why don't you supply a few photos of the setup showing how was built to see if there are other arrangements like installing more RAINBOW Nozzles that are not expensive with ball valves to close or open the ones needed.

Do you have capabilities to build one, Lathe work ?.

Nando

[Flux]

If you have a lathe you should be able to make an adjustable nozzle, You could roughly follow the shape for large ones, I am sure you can find a picture, if not I may have something I can scan. The main thing will be to keep the needle rigid and concentric within the orifice. You will probably have to use stainless steel unless your water is very clean with no abrasive in which case gun metal may be ok.

You may also be able to use 2 or 3 fixed nozzles as Nando suggests.

Flux

[cricker]

Thanks for the replies. I have a lathe and all the rest plus 25 years of the trade. I have the stainless material. The proportions of needle to orfice and the diameters of all the parts as well as the angles involved would be a guess and I think that efficiency would be compromised by guessing. I've seen some photos of them with little slots along the needle. I couln't begin to know how to dimension those or if thats important.  I could scale up or more likely, down if I had examples of proven designs. I am trying to do more than just make it work, while its in the lathe I might as well build it right. I agree that a number of nozzles with all the plumbing will work but I would still have to walk down the hill every day to change settings. Of course electric actuators are an option for the ball valves. I really would prefer a stepless arrangement. Either way I will need an indicator of the forebay level probably using a float attached to micro switches to avoid having wo walk up to the intake every day. I already have wiring from the intake to the control shack (near the house) and then down to the genny, consisting of twelve conductor phone line. Unless needle nozzles are inherently inefficient I would like to pursue this course. Are there none available commercially?

I have some photos of the genny but none of the show the working parts, I will try to remedy that. If your interested I can describe the installation in detail, but that wouldn't have much to do with the nozzles.

Thank you for your time,

Cricker

[Flux]

Cricker

If this works, I have scanned a diagram of a larger nozzle. You are working at such a small scale that you are not going to be bothered  by slots etc, I am not sure how well these things scale to such a small size anyway s0 think you are in the land of experiment.

As long as you keep the basic shape and keep your surface finish good I think you will be ok. Theory is all very nice but water flow is not an exact science even now and if you manage to find a source of a commercial nozzle that small it will have been produced by experiment. Hope the sketch helps.

Flux

[Trivo]

Looks a lot like a Carburettor needle valve

Trivo

[cricker]

Thanks, Flux, for your drawing. I can't read it but can see the shape. I wouldn't have known about the inverted bell shape. The few photos seen appeared to have straight tapers. I guess experimenting is what I'll have to do. I see where Power Pal uses a spear valve but their not showing any detail. I still want to do this and if anyone has more info I'll be appreciative it would save me lots of time and electricity for the lathe.

Regards,

Cricker

[Flux]

Cricker

It is nearly impossible to read the original, the figures are someones measurements to calculate the area of the orifice at various points. As there is no horizontal distances given it would not help you with the shape.

I have done a few rough measurements that may help you. The inside angle of the orifice is 70 deg as is the angle of the needle at that diameter so it all closes off at that angle. The angle of the needle at half orifice diameter is about 30deg and the tip angle of the needle is 10 deg. The active bit of the needle from tip to closure point seems about 2 x orifice diameter.

I think the shape is chosen so that flow is roughly proportional to needle displacement as this makes life easy for the governor. I doubt if it has much other effect on the jet efficiency.

Flux

[nanotech]

As Trivo said, those look an awful lot like carburetor jets.  A lot of the smaller Honda and Yamaha motorcycle engines used those type for thier throttle...

Best bit, they're threaded into place, so easy swap out.

[w32514]

Use multiple nozzles with a solenoid valve on each.  Wire each solenoid to a float switch with different settings.  Get normal closed solenoids so they only draw power when you have extra water.

[Nando]

CRICKER:

The drawing you got is for large Spear Nozzles for large Peltons and Turgos.

For small ones the Spear can be made straight, without out any body length curving and the cover is also made straight and mating the diameter of the spear when is in maximum closed position.

This is the form that has been used by many for several decades -- If interested in building one, I can assist you -- you may end up making several sizes to sell at a good price -- new business for you.

Regards - nando37-at-comcast-dot-net

Nando

[cricker]

Hello again,

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 a 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