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Airless Misting System
- Thread starter jweaver72
- Start date
- Joined
- Jan 16, 2020
- Messages
- 8
I do not yet have all of the drawings finished, but here is part of what I have, the overview, and the mixer block in PDF format. I originally designed it where the nozzle, extension tube, and mixer block would be made of brass and soldered together, but am having second thoughts on that. If those parts thread together, any material could be used for the mixer block. So, I have to update the drawings and get them dimensioned yet.
There are a couple of things that are key to the way this thing works:
1. The reservoir must be pressurized so that the coolant is pushed up to the mixer block. It cannot be 'drawn' by venturi effect.
2. The nozzle and the port where the coolant meets the air are only .040" while the air passage is quite a bit larger. This slows the air flow down so that it does not atomize the fluid as it carries it along.
In the drawing of the mixer block, the air comes in on the left side and the coolant enters through the bottom. The two valves shown are brass needle valves made for aquarium aeration. This design currently uses one regulator so that the fluid and the air are at the same pressure, but some guys have been using two separate regulators to gain better control over both pressure and flow. I plan to try the single regulator system first, and if that does not give enough control I will add a second regulator and try that.
If any of you see any problems with what I have so far, feel free to speak up. I would rather correct problems now rather than later.
There are a couple of things that are key to the way this thing works:
1. The reservoir must be pressurized so that the coolant is pushed up to the mixer block. It cannot be 'drawn' by venturi effect.
2. The nozzle and the port where the coolant meets the air are only .040" while the air passage is quite a bit larger. This slows the air flow down so that it does not atomize the fluid as it carries it along.
In the drawing of the mixer block, the air comes in on the left side and the coolant enters through the bottom. The two valves shown are brass needle valves made for aquarium aeration. This design currently uses one regulator so that the fluid and the air are at the same pressure, but some guys have been using two separate regulators to gain better control over both pressure and flow. I plan to try the single regulator system first, and if that does not give enough control I will add a second regulator and try that.
If any of you see any problems with what I have so far, feel free to speak up. I would rather correct problems now rather than later.
- Joined
- Jan 16, 2020
- Messages
- 8
I must admit that mine freezing up was something of an anomaly, but I cannot figure out any other reason. The compressor had been used heavily that morning for about four hours, but I do not know if that contributed to the problem or not. When I found that it turned freely in the spring, I immediately pulled both heads and found no signs of scoring or damage, just a couple of rusty spots where water had collected on the walls of the cylinders up against the tops of the pistons (it was a two cylinder V-configuration compressor). The thermal overload for the motor did eventually kick out, but I don't know how long it sat there humming and groaning. It is possible that the motor was marginal as it was before this problem occurred. All I know is that I could detect the motor damage with my nose when we got home. It was bad enough that the smell got from the garage into the house and SWMBO was NOT happy about it!
My wife is also quite happy that I am getting a quiet compressor, as the large one in the garage can be heard throughout the house when it lights off. The vibrations it sets up travel through the concrete and no part of the house is immune from it. I will save it for large projects, like running impacts, changing truck tires, etc., running it only when necessary and keep some peace in the family!
- Joined
- Nov 17, 2013
- Messages
- 36
terrywerm;167013My wife is also quite happy that I am getting a quiet compressor said:I'm in a similar situation but for, the air compressor kicking on will remind them where I am atJust kidding.
I looked at the drawings you attached and although being so new at this I do not have a lot to add but being in the electrical business for my entire career and relating electrical flow to that of fluid or air, the only concern I would have with the one regulator set up would be the relationship both nozzles will have to each other when you are adjusting flow. I don't think it will be a game stopper but when adjusting one you will ultimately adjust the other.
For instance, if you have 10 psi and you are dividing it equally between coolant and air and then you adjust the coolant to 4 psi, your air will increase to 6 psi. this could create difficulties in getting that fine tune you are looking for.
Other than that, it looks great.
- Joined
- Jan 16, 2020
- Messages
- 8
Considering that the regulator can supply more CFM of air than the two aquarium needle valves together can pass, and considering that this system will use air and coolant in very small amounts and at low pressures (5 to 10 PSI), there should be little if any detectable pressure drop up to the point of the needle valves, provided that the delivery lines are of adequate size and not overly long. So, pressure should remain fairly constant, and tuning the needle valves to the required flow should not present any issues for each other that I can think of.
On the other hand, I am not a fluid dynamics engineer, so I might be so far off that readers with fluid power backgrounds are now laughing heartily, and the guffaws can be heard at great distances. :headscratch: If that is the case, I am sure that they will offer their professional advice later this week after the laughter subsides. :allgood:
Like I said earlier, I will be experimenting as I go once I have it built, and, based on past experience with coolant misters, there is quite a bit of latitude in the settings, and I suspect this is especially true if the coolant is provided under pressure. So, we'll see what happens. Oh, and I'll start a separate thread on that, too, but will post a link to it in this one for everyone's convenience. And, since everyone likes lots of pictures, I will document the entire build, too.
On the other hand, I am not a fluid dynamics engineer, so I might be so far off that readers with fluid power backgrounds are now laughing heartily, and the guffaws can be heard at great distances. :headscratch: If that is the case, I am sure that they will offer their professional advice later this week after the laughter subsides. :allgood:
Like I said earlier, I will be experimenting as I go once I have it built, and, based on past experience with coolant misters, there is quite a bit of latitude in the settings, and I suspect this is especially true if the coolant is provided under pressure. So, we'll see what happens. Oh, and I'll start a separate thread on that, too, but will post a link to it in this one for everyone's convenience. And, since everyone likes lots of pictures, I will document the entire build, too.
- Joined
- Jan 16, 2020
- Messages
- 8
The needle valves came from an aquarium supply house that I found on the net - petsupplies.com They are a Supreme brass air valve, item number 721217, $5.32 each since I ordered six of them. 1/8" NPT on one end, and has nipples for aquarium hose on the other end. While I placed my order with them, I also bought 25 feet of silicone tubing to hook it all up, item number 720518-25 for $4.09. Since pressures will remain extremely low, the simple push on tubing should work, but if it starts to push off of the nipples, I can make some simple hose clamps out of stainless welding wire to keep things in place.
I am currently working on the final details for the drawings, which include a bill of materials and list of where I obtained them, along with current cost. For example, the water filter housing was quite inexpensive since I bought a smaller one without all of the doo-dads and bells and whistles: It was only $7.99 from filtersfast.com. I had to purchase the bracket and the bowl wrench separately, but they totaled another $9.44. All in all, not too bad. A person could probably get away without the bowl wrench, but I have a filter similar to this for my house water system, and after a few months it gets like it is glued on there. Trust me, the wrench is well worth it! I could just use the wrench that I already have for the home water filter, but I keep that hanging in the utility room, right next to the filter and I don't want to have to hunt it down all the time, so I just bought another one for this project.
The most expensive item for this project was the brass bar from which I cut the mixer block. A 12" length of 5/8" x 1 1/2" brass bar was $42, but I wasn't too concerned as I will use it up for myriad other projects as well. A person could make the mixer block out of aluminum or even plastic if he wished, but I really like the look of all-brass. My original plan was to solder the nozzle, extension tube, and mixer block together, which would have required brass, but I revamped my plans for those parts so they could thread together, cutting the material cost for those that just happen to have the right chunk of material lying around or those who are working on a tighter budget than myself.
As already mentioned, I am putting the finishing touches on the drawings and should have them posted soon. Each time I go over them I find some little detail to address, or so it seems.
I am currently working on the final details for the drawings, which include a bill of materials and list of where I obtained them, along with current cost. For example, the water filter housing was quite inexpensive since I bought a smaller one without all of the doo-dads and bells and whistles: It was only $7.99 from filtersfast.com. I had to purchase the bracket and the bowl wrench separately, but they totaled another $9.44. All in all, not too bad. A person could probably get away without the bowl wrench, but I have a filter similar to this for my house water system, and after a few months it gets like it is glued on there. Trust me, the wrench is well worth it! I could just use the wrench that I already have for the home water filter, but I keep that hanging in the utility room, right next to the filter and I don't want to have to hunt it down all the time, so I just bought another one for this project.
The most expensive item for this project was the brass bar from which I cut the mixer block. A 12" length of 5/8" x 1 1/2" brass bar was $42, but I wasn't too concerned as I will use it up for myriad other projects as well. A person could make the mixer block out of aluminum or even plastic if he wished, but I really like the look of all-brass. My original plan was to solder the nozzle, extension tube, and mixer block together, which would have required brass, but I revamped my plans for those parts so they could thread together, cutting the material cost for those that just happen to have the right chunk of material lying around or those who are working on a tighter budget than myself.
As already mentioned, I am putting the finishing touches on the drawings and should have them posted soon. Each time I go over them I find some little detail to address, or so it seems.