I'm an ardent (if inexperienced) gardener, and one of the things I've found seems to help one's veggies grow is to water them regularly, especially when it's hot and dry out, as is so often the case here on the prairies.
I'm primarily interested in getting a good volume of water onto the plants, without having to wait too long to do it, and without too much of the water being misted off in the wind. Also I like to be able to target the water flow to a specific group of plants, as well as control the amount of water comming out to some degree. All the watering nozzles I found at the local vendors seemed to have one or more of the following problems:
I had previously installed a ball-type shutoff valve on the hose end, as well as a female quick-connect, so I figured that flow throttling was taken care of, as long as I could find a way to burn off the velocity and misting the water picked up while ripping through the orrifice. Skipping some details of the developement effort, I'll describe the finished product, with pictures.
The above picture shows a side view of the tool. Starting from the left, we have an "Orbit Sunpro" male quick-connect (aside, their sunpro line of female quick connects are the best constructed ones I've seen, although I'm not necessarily wild about the EPDM grips. Make sure you get the ones with the o-ring in them.), next is a brass line adapter that goes from (I believe)1/2" pipe to a 3/4" male NPT, next a female 3/4" NPT to male 1" NPT, then female 1" NPT to male 1.5" NPT, and finally a 1.5" NPT threaded cap. There's another component inside which I'll describe later.
The inside of the quick-connect hose thread was torch-soldered onto the outer surface of the brass pipe adapter. Note that since neither of these is a functionally controlled surface, you'll need to check (and adjust) the fit. I found that with a slight shave on the lathe these two were a nice, snug fit. A wise individual would have made sure to use a lead-free solder here, but I'm not that wise. Obviously the rubber ring was removed before soldering. The other components were simply threaded into place. No sealing tape was used, because this is a watering tool. Who cares if it drips.
After soldering I machined the male hose thread off the quick connect. I though it looked ugly. You can see the odd lead spot around the joint, although I tried to clean off most of it.
Before assembly I drilled this happy patern of holes into the cap. For the prototype I hand drilled them (and it shows). For the real ones I used a drill press and proper spacing shims to get a more even water patern. If doing this yourself, think about the spray spread you want, and make the outer angles accordingly. I used a hole size of about 3mm, which gives a good spray in my humble opinnion. The picture shows the prototype, which has fewer holes, and a less even pattern than the final version does.
What cleverness there is in the design is in the flow spreader inside. If this object was simply put onto the end of a hose, there would be a very uneven distribution of output flow, as the hose jet would smack right into the central holes, while the peripheral ones would only dribble. I fixed this by cutting an "Iron-Cross" shaped piece of copper plate (2mm thick) and turning it into the threads of the 1" to 1.5" bushing. This holds it quite securely in place, with the centre of the cross catching the water jet. I chose copper because in isolated contact with mains water it should last many decades of normal use, and it's easy to work. That being said, it may end up being the quickest wearing part of the design, as the rest should be almost immortal.
The water has to do two 90 degree turns to get past the cross, and ends up burning it's kinetic energy in the resulting turbulence. By the time the water flow gets to the cap it's slow and even, resulting in a nicely spread fountain of even spritzers emitting from the pipe cap.
It'll take you a bit of trial and error to get the cross the right size. You want something that just barely mates with the threads at first, but get's good and tight by the time it bottoms out.
What's good about the design?
What's no so hot about it?
Flow resistance is so low that I can't tell the difference in hose feel with/without the tool installed. Actually you can open the retainning ring on the quick-connect while the valve is wide-open, and the tool won't come off <- low back pressure.
Cost for the materials is about CDN10. The ball valve and quick connect are about another CDN10. If anyone is interested in building their own, let me know and I'll put up a better picture of the final hole pattern.
What would I do differently next time: Not much. They work quite well. If I make any more I'll keep the same pattern in all respects.
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