Built a nozzle today and have some questions about lighting...

Hi Everyone,

I was building some RGB colour scrolling pond lights for a friend, and whilst doing some research to see what kinds of LED pond lighting you can buy off the shelf, I came across these laminar jet fountains. I had seen these on TV a while ago (a demo by Wet Labs in Vegas) and I always thought I should try making one, and so this time I thought I would.

I started gathering parts at lunch time and by about 5pm I had a working nozzle. I am getting about 8ft distance and about 4ft arc height with it using a standard household water outlet tap (turned down low!)

The nozzle consists of a bit of 4inch PVC pipe, with a two sockets, one on each end and an end cap in each socket. One end cap has the water inlet, and one has the nozzle. I made my nozzle from a thin bit of plastic and I reamed the hole out smooth and glued it onto the inside of the end cap.

I am using two layers of spontex scouring pad before the straws, and I decided to use very small diameter drinks straws. Not sure if thats a good idea or not, but it seems to be working, diameter on the straws is about 3mm. I am using about 1200 of them.




I also used some bits left over from my RGB pond light and I installed four bright diodes, I made a little PCB for them and sealed it, then positioned it under the outlet, about an inch below. They are quite bright diodes.

I turned the system on, and the stream dosn't light up, instead where the stream lands, it creates a pool of coloured light. This is quite nice, but what I really want is the light to shine off the stream. Do I need more light?

When I interrupt the stream, by flicking my finger through it, I get a really nice jumping light that flies along the stream.

Could it be that I have accidentally created quite a good laminar stream first time round (beginners luck?) and all the light is being efficiently transferred down the stream to the end?


Any help would be great.

Thanks,

Pete.

PS - Thanks to Mario for linking me to the forum via a Youtube message.

Welcome, and congratulations on making such a nice stream!

Yes, that is exactly what is happening. Laminar streams are too effective at transporting the light (like fiber optics). There are a couple of ways to fix that problem. One put something in the water so that the light will hit and bounce off the substance and light up the stream. This is good, but could damage the pumps, filters and such. I tried this once with just a cap full of vegetable oil. It worked pretty good, but I think the stream suffered due to a bad reaction with the pump.

Second is to put a scratcher just on the exit. Essentially you are going to put a screw tip into the water. The fiberstar laminar jet does this.

Third is to add more powerful leds, or lots more of them.

Fourth is the tapping method which only provides a temporary brilliant light.

Essentially you need to destroy the quaility of the stream, add something to the water, or add more light. Maybe all of it?

Hi,

I have just re-fiddled my nozzle. I took out the old output nozzle (a bit of plastic with a hole drilled in it) and replaced it for a much sleeker one. I found a bit of aluminium and used the cnc lathe to make a nice sharp knife edge nozzle and glued this on to the front of the tube.



This works 10x better, I am getting a fantastic still laminar stream for a bit, and then it starts to go rough. I have it aimed into the pond at the moment, and when the stream hits, it makes no noise at all, which is nice.

I think I will take it all apart and make it a bit neater, some of my straws have started moving about.

I am also going to put the water input in at the side, should this help even more?

I am thinking that I might turn up a really nice brass nozzle for the jet. Would anyone on this forum be willing to help me design it, and we can possibly sell a few of them or make them to order?


Jet on youtube

I have some brass ones for sale if you want. If you want to just make your own it's pretty simple, all you have to do it make a hole and then countersink the hole.

Just tested the jet again, and the stream stays laminar for a bit but then goes rough. What could be causing that?


Pete.

Are you trying to push more water through it, or the same amount. If I remember correctly you are using a 4" tube?

Hi John,

At the moment I am just using the garden tap.

Its A 4inch diameter pipe with a 10mm dia exit nozzle.

I'm assuming that you aren't trying to push more water through it compared to the last time.

Most of the time people deal with issues of pump jitter at the beginning, but since you are using a tap it SHOULD be ok.

1. I guess what I would look for is to make sure all the air is out of the nozzle.

2. Examine the exit orifice closely, do you see any nicks etc? Those will also affect the stream quality.

3. From experience the 4" with a .5" diameter nozzle didn't produce great results in the first place.

If you can start to quantify the amount of water it is using (i.e. measure the flow rate). Pictures help a ton too!


Oh and untreated aluminum will corrode over time. I don't imagine that quickly, but maybe examine that.

My nozzle consits of (input to output)

20mm dia input pipe at a tangent to the tube, which is 4inch soil pipe.

About an inch above this there is a green scouring pad, then another inch gap, then a steel mesh, and the 1200 small drinks straws. the straws are about 3mm ID and are about 120mm (approx 5 inches)

Above the straws there is a 3 inch space, then my custom made 10mm dia nozzle which is clean and perfectly round.

will stick some photos up in the morning.

Any advice would be great.

Thanks,

Pete.