No Fog Coolant Mister

[Terrywerm]

The plans listed below are for building your own no fog coolant system to use in your shop. Compressed air is required, but the design will apply coolant to your cutting tools without creating a foggy mist in the air when it is used properly. In practice, the air volume is turned up just enough to gently blow chips away from the cutting area, which will also carry small droplets of coolant to the tool.

Most dimensions can be changed without issue, however there are two dimensions that are critical: the .040" hole in the mixing block, and the .040" hole in the nozzle. The air passage through the mixing block must be large enough to slow the speed of the air flowing through it, but must be small enough for the air to travel fast enough to carry the droplets of coolant along.

I made my mixing block from brass for three reasons, but aluminum could be used: 1. I like the look of brass 2. It was what I had 3. Allows assembly by soldering if desired

The drawings show using only one regulator on the system, but two can be used, providing different pressure settings for the mixer air and for the fluid reservoir.

This coolant system could be used with any light coolant, such as Kool Mist, WD-40, or even soluble oil. Heavy cutting oils will most likely not work well with this system.

The drawings and bill of materials depict the system as I am currently building mine. If it becomes necessary to make changes to a drawing, I will do so and post the revised drawing here, replacing the original, then will post a note to the thread. As always, some individuals will do some things differently, and that is okay.

Comments and ideas are welcome, let me know what you think.


View attachment NO_FOG_MISTER_001.pdf - Coolant system overview
View attachment NO_FOG_MISTER_002.pdf - Regulator and air fittings
View attachment NO_FOG_MISTER_003.pdf - Reservoir and fittings
View attachment NO_FOG_MISTER_004.pdf - Reservoir modification details
View attachment NO_FOG_MISTER_005.pdf - Mixer head assembly
View attachment NO_FOG_MISTER_006.pdf - Mixer component details in English/Imperial measurements
View attachment NO_FOG_MISTER_006M.pdf - Mixer component details in Metric measurements
View attachment NO_FOG_MISTER_007.pdf - Bill of materials


ON EDIT: I discovered an error on one of the drawings regarding the nozzle size, and it has been increased from .040" to .090" and it works much better at this size. Alternatively, the nozzle could be eliminated and the coolant could exit directly from the extension tube.

All drawings have been updated as of 1/11/2015

 

[wrmiller]

Thanks Wermie! Already downloaded and queued for one of my next projects.

Bill

 

[bpratl]

Thanks again for a great project, design and layout.
Parts are now on order.

 

[yohan]

Brilliant Idea! something I will be trying out shortly

Thanks for Sharing!

Johannes

 

[Chucketn]

I also downloaded and printed the plans and the No Fog Mister is on the to do list. Thanks for sharing Terry!

Chuck

 

[Terrywerm]

For those who work in the metric system and have already downloaded the plans, go back to the initial post in this thread, as I have added a metric version of drawing 6 which contains all of the critical dimensions. Sadly, not everything converted over correctly, but most things did. It should make things easier for you anyway.

One other thing: I mentioned assembly of the block by soldering if desired. After giving things more thought, I think it would be a good idea to thread the block, extension tube, and nozzle for assembly. This would allow disassembly in the event of foreign material getting into the mixer and plugging it up. Cleaning it all out would be much easier if it can be disassembled.

 

[melsdad]

Thanks Wermie! This looks like a great project. The drawings and parts list are top notch!

 

[LJP]

Nice set of drawings! Simpler than I thought it would be to make. Thanks

 

[TomS]

The plans listed below are for building your own no fog coolant system to use in your shop. Compressed air is required, but the design will apply coolant to your cutting tools without creating a foggy mist in the air when it is used properly. In practice, the air volume is turned up just enough to gently blow chips away from the cutting area, which will also carry small droplets of coolant to the tool.

Most dimensions can be changed without issue, however there are two dimensions that are critical: the .040" hole in the mixing block, and the .040" hole in the nozzle. The air passage through the mixing block must be large enough to slow the speed of the air flowing through it, but must be small enough for the air to travel fast enough to carry the droplets of coolant along.

I made my mixing block from brass for three reasons, but aluminum could be used: 1. I like the look of brass 2. It was what I had 3. Allows assembly by soldering if desired

The drawings show using only one regulator on the system, but two can be used, providing different pressure settings for the mixer air and for the fluid reservoir.

This coolant system could be used with any light coolant, such as Kool Mist, WD-40, or even soluble oil. Heavy cutting oils will most likely not work well with this system.

The drawings and bill of materials depict the system as I am currently building mine. If it becomes necessary to make changes to a drawing, I will do so and post the revised drawing here, replacing the original, then will post a note to the thread. As always, some individuals will do some things differently, and that is okay.

Comments and ideas are welcome, let me know what you think.

View attachment 67210 - Coolant system overview
View attachment 67211 - Regulator and air fittings
View attachment 67212 - Reservoir and fittings
View attachment 67213 - Reservoir modification details
View attachment 67214 - Mixer head assembly
View attachment 67215 - Mixer component details in English/Imperial measurements
View attachment 67267 - Mixer component details in Metric measurements
View attachment 67216 - Bill of materials

After searching this forum on coolant delivery systems I came to the conclusion that flood and misting, while having good points, also have negatives that led me to your post on no fog cooling. I liked the concept and decided this is the way I wanted to go. Most of what I did was as described in your post and drawings. I made a few changes mostly because parts and material were on-hand or could be purchased locally. The following pictures show my installation.

What troubles me is I can't get a steady flow of droplets. I've varied the air pressure from 3 psi to 60 psi and adjusted the needle valves and either it intermittently spits out coolant or I get a steady stream of liquid out of the nozzle. Tried it both with one regulator as shown on the drawings and with two regulators; one controlling the air pressure to the nozzle and the other controlling the air pressure to the filter housing. The pressures are extremely sensitive to adjustments. Is this normal? What pressure should I run at? It's flowing way too much coolant and empties the filter housing in about three minutes of run time. I'm missing something but can't put my finger on it. Any help is appreciated.

Tom S



Photo 1 - Picture of the metering block. The upper left needle valve is the air feed to the nozzle. The nozzle is fed by the clear Tygon tube that loops down and under the metering block. The bottom needle valve is fed from the outlet of the filter housing. The metering block is drilled and tapped 1/8" NPT for the needle valves with a .040" diameter hole in the nozzle feed circuit.



Photo 2 - Picture of the regulators. The black hose is the air feed to the filter housing. The left regulator is plumbed into a pipe tee that is not visible in the picture and is plumbed to the metering block.



Photo 3 - Not a good picture. The nozzle tip has been fitted with a brass plug with a .040" diameter hole in it.



Photo 4 - Picture of the filter housing plumbing. The black hose comes from the right hand regulator shown in Picture 2. The 1/4" nylon tube on the outlet side of the housing feeds the lower needle valve on the metering block.



Picture 5 - Another picture of the metering valve plumbing.

 

[Terrywerm]

Tom,

I would first try enlarging the hole in your nozzle, it's size is not so critical as the .040" hole in the mixing block. You might even try removing the nozzle. Once you've done that, you can use more air flow to carry the small droplets to the work.

What is happening right now is that the air starts to carry the droplets at the mixing block as it is travelling at a velocity high enough to do so. Once the air/coolant stream hits the large inner diameter of your flex hose, the velocity is greatly reduced and the fluid droplets drop out of the slower moving air. Once the liquid forms a large enough 'puddle' in the flex hose, the air pushes all of it out at once. You also might be opening your fluid needle valve too far due to the perception that there is no coolant coming through.

The original design called for a straight nozzle that is relatively short in length, and small enough in diameter to keep the air velocity high enough to still carry the droplets, but not so high that the droplets become atomized, thus not creating a fog in the room. The flex hose you are using may be what is causing the problem.

I made a prototype that worked reasonably well, but it was a bit bulky. The mixing block was too large, as were the needle valves that I used in the first design. The design in the drawings is a smaller version of that prototype, and I still need to build one of the smaller ones. The needle valves are sensitive, especially if they are overly large, but the sensitivity is not as bad at lower pressures. You should only need about 20 PSI at max, maybe a hair bit more, but probably less in most cases. You are looking for air volume, not pressure. A higher volume stream, at lower pressures, can carry tiny droplets of fluid in the air stream. Air will provide most of the cooling, aided by the cooling effect of a tiny bit of fluid.

In use, you should turn on the air first. Get a nice flow going at a lower pressure, but not so much flow that it gets real noisy. Next, just crack the fluid valve open a tiny bit while holding a finger out ahead of the nozzle. When the fluid starts coming, you may not see it, but you will feel it as the temperature of the air stream will drop sharply. If you watch closely you will see that your finger is starting to get wet, but not dripping wet. That is all you need. One canister of coolant should last for several hours, as in all day or more. Granted, a heavier milling job will need a bit more coolant, but you will be surprised at just how little it really takes.

Fiddle with your modifications a bit, then come back and let us know how you've done. Feel free to tell us what works and what doesn't, and don't be afraid to critique my design if you find a flaw with it, even if it is only a personal preference. I am going to be out of town for a couple of weeks, but will check back here when I return.