SOLVED high capacity humidifier

[car54]

Many times I have read that people would like a high capacity humidifier tank of which I agree. The Resmed tank holds 1 cup. After studying the tank, this is my solution.
It took about 45 minutes to make it after a couple of hours figuring out what I could use. I wanted parts that could be easily converted and I wanted it simple.
I used it last night and it works.

 I wanted the bottle to be plastic, wide mouth, be about 6 ounces and angled. A playtex baby bottle worked. I would have used a Lixit wide mouth small animal water bottle if I wanted to order it.


   

   

   

Link for water bottle

https://www.chewy.com/lixit-wide-mouth-s...t&utm_term=

Car54

[Big Guy]

That looks to be a good & easy fix for a problem many seem to experience. Well done! 

Not sure why though others have such an issue and I rarely ever had to deal with it? I think maybe twice or so, my water reservoir ran dry during the night.

[Ratchick]

That is amazing and I have a spare tank to butcher. I may give it a go with the help of my handy roommate!

[car54]

I would just doing a test on some other material. The rubber bushing is an electrical grommet. The tube that goes through it has to be very snug to prevent leaks.

[kappa]

Not sure why though others have such an issue and I rarely ever had to deal with it? I think maybe twice or so, my water reservoir ran dry during the night.

Agree that this is a neat solution. I expect having a tube of sufficienctly large diameter which sits above the base of the tank (say 1cm above) is cricital here in order to allow air to get past the water in the tube and up into the bottle.

Assuming that one is using the 'auto' humidity setting, which delivers air with 85% relative humidity, water consumption will be determined by room humidity, tube temperature setting, PAP pressure and any mask leaks. PAP pressure determines 'intentional' leak rate through mask vents which adds to unintentional mask leaks to determine total airflow, so total volume of air that needs to be humidified. Warmer air carries more water so higher tube temperature uses more water.

For example, a pressure of 12cmH2O gives an approximate flow of 34.2L/min, which is around 2 cubic meters of air per hour. At 20C/68F water carrying capacity of air at saturation is 17.3g/m3, while at 30C/86F it is 30.4g/m3 (according to engineeringtoolbox). So if your room humidity is 50%, water consumption should be (85%-50%)*2*17.3= 12.1mL/h @ 20C/86F and 21.3ml/h @ 30C/86F.

So if you sleep in a dry environment (e.g. air conditioned room) and/or have high pressure and/or mask leaks and/or use a higher tube temperature then you are more likely to run out of water.

[car54]

Kappa,
 The tube has to be below the high level mark so that it does not flow back into the blower. I put my about 1/2 way down.  When the water is drawn down far enough, it will allow the secondary reservoir to operate.
The tube I used was 3/8 inch OD with a 1/4 inch ID.
Do some daytime testing with it before using for sleep to tweak in any adjustments.

Here is a picture of the tube assembly. I put a 3/8 inch thread on it with stainless steel washers plate and jamb nuts. I have all the materials and tools at home so putting the thread on was no problem. I cut the nipple off the baby bottle(not shown) and used that as a gasket between the plate and the bottle. Ultimately I will cut the tube to length so when the nut hits the humidifier tank the tube will be at the right height. The tube(pipe) is available at Home Depot or Ace hardware

If you use the animal water bottle everything is done for you but the one way valve at the end of the tube would have to be removed. I do not know what the tube OD is on it and that would determine what rubber grommet you use.

   

[cberistain]

Kappa:  wouldn't the amount of air drawn in on each breath also have an impact on the amount of water consumed? a large person probably requires a lot more air per hour than a petit person.

[kappa]

cberistain, you breath out the same volume of air (essentially) that you breath in, so the air that needs to be humidified is based on how much air is lost due to total leaks.

Here's a total flow graph from a F&P machine:
   
Note that only a small amount of flow measured at the machine is negative (i.e. back through the machine). This may increase at lower pressures and with higher breath volumes, and the impact might be to reduce the amount of humidification required as the humidity sensor would see more exhaled air which likely has higher humidity.

Regardless, water consumption can be reduced by reducing tube temperature, or by addressing mask leaks, or by increasing room air humidity.

[Given the small amount of air going back in to the tubing it begs the question on how well the external cartridge HME (heat moisture exchange) humidification systems can work for many people].

[Ratchick]

Given that I sleep forever and have relatively high pressure, plus central heating causing extra dry air, that explains a lot. Leaks aren't really an issue for me, but the rest is.

[DaveL]

Given that I sleep forever and have relatively high pressure, plus central heating causing extra dry air, that explains a lot. Leaks aren't really an issue for me, but the rest is.

I had capacity issues with my S10 reservoir.  

Then my ukulele cracked....Canadian furnace with no humidifier.

Installed a humidifier on the furnace in the basement and that solved the capacity problems.  Actually, had a company install it.  Cost twice as much as the ukulele....