Dryer for CPAP Hose/Mask

thingiverse

This is my first publicly shared design. This is a dryer to attach to your CPAP hose after cleaning it to allow it to dry. I noticed that when I cleaned mine, if I hung it to dry water droplets never dried and I thought that was a bad thing. After plugging it into my hose for the first time I could feel the high level of humidity that was coming out of the other end of the hose, that just further reinforced my idea that I wanted to get air moving through the hose (even if just a little) to help it dry. I found a unit that was very similar on Thingiverse designed by A1XT (https://www.thingiverse.com/thing:3809211) - hope I am crediting this person properly, but whomever designed it intended it to use a non USB fan and I was not able to make it work with the USB powered fan that I wanted to use. At first I tried to make my own design modeled more closely after the one that I found, and it worked ok but it had one pretty significant flaw. Unlike my inspiration design, versions A and B limited the filter surface area to a surface area only the size of the fan blade diameter. It was creating so much drag that it was pulling the fan speed down. Yeah the design worked but it didn't work as well as I wanted (reduced mass flow) and I was concerned that it would reduce the life of the fan. That takes us to this design. There have been a number of changes from my rev A to my rev C but in a nutshell the biggest changes included in this design are: 1. this design has a much bigger base so it is more stable on the nightstand 2. this design includes removable filter frames to make changing the filters easier 3. this version includes an integrating cavity between the fans and the filters to assist in load sharing between the filters 4. this design changes the effectively used filter exposure to use almost the entire surface area of the filter 5. this design includes a second filter in parallel to further minimize the pressure drop So far so good, it seems to be working much better than my original attempt. A few suggestions on materials: 1. This design uses a 40mmx40mmx10mm fan, the version I am using is USB powered since I have an alarm clock with a USB port so USB is very convenient. I found it on Amazon in a two pack here: https://www.amazon.com/dp/B074YJH3P9?psc=1&ref=ppx_yo2ov_dt_b_product_details. I am including my FreeCAD design files in the downloads section so if you want to tweak the design you are welcome to do so (for example if you wanted to use a 40x40x20 fan instead, but I found this fan works fine). 2. This design is using filters that fit an airsense 10 CPAP machine which I also got off Amazon here: https://www.amazon.com/dp/B07DMGMC54?psc=1&ref=ppx_yo2ov_dt_b_product_details. Nothing special about this brand, just happens to be what I used. 3. I sized the mounting holes for M3-6-5 threaded thermal inserts to receive the four M3-20 screws that hold the nozzle on (and in doing so hold the fan in place). If you are not going to use thermal inserts then these holes are likely too big to try and tap directly into the plastic and you will need to change the design to make them a smaller diameter - again, I included the actual design files, you just need to change the diameter in the spreadsheet to change the design to a smaller diameter hole. I am including how I printed it below but there is nothing terribly special about my material and print settings. I am sure that this work work just as well using different materials and settings, so use your best judgement. PLA might work even better for the nozzle due to its smoother finish compared to the EZPC-CF I am using. There is ABSOLUTELY NOTHING in this design that justifies using a carbon fiber polycarbinate material, it is just a material I am playing with and have discovered that I really like - but be warned to print with it you need an all metal hot end and a hardened or Ruby/diamond nozzle. One suggestion... I did put support suppression blocks over the holes that will receive the thermal inserts. I am not concerned if the lid droops a bit because I am putting in the thermal inserts anyway. 5/28/23 - update.... I have discovered something... If I take my hose and move it from my machine to this little blower every morning, I don't need to clean it nearly as much or as often. Because I am using this gizmo daily and not just when I clean my mask I found it easier to install a switch. I found the following which is working great for me. Take care all... https://www.amazon.com/dp/B07T9BRNHW?psc=1&ref=ppx_yo2ov_dt_b_product_details