A bit of advise/help..Design for heating air flowing into cold weather mask

[jarity]

Hello members,
What i need help/suggestions with is concerning heating a plate thru which cold air flows on it's course to the face mask. This plate is designated as number "3" in the drawing (page 1). Not sure rather:
1. To simply thread nichrome coated wire thru said plate
2. Increase the number of plates.
3. Use (2) 5 watt power resisters in series (as i need 10 watts) of which i have no idea how to do
4. Or dispense with the plate concept altogether and coil coated nichrome wire around the outside dia. of the aluminum tube using it as a heat sink(#4 in the drawing on page 1)
What i am concerned about is will the air have enough time in passing thru the chamber to bring it up to the 60-75 degrees i need for breathing.(I have copd and cannot tolerate air below 45 degrees for long which makes me a virtual prisoner in winter)

Mask (shown on page 2) has a one way outlet valve.

The arithmetic is mostly worked out (By other. See page 6)
With air flow volume at 50 liters/min and temperature at 27 degrees 8 watts is needed to bring air up to design temperature of 60-70 degrees. (Taking a 10 watts figure)

On order at present (links are on page 3)
1. -temperature controller.
2. -sensor to warn me when my battery falls below a certain voltage.
3. -5000mAh 11.1 volts battery-rechargeable Lipo Pack

This has been a bit long but i wanted to include enough info.
Thanx for any time you may have to address my problem.

 

[crutschow]

Transferring the heat to the air could indeed be a problem. You want a lot of surface area to the flowing air, the more the better. I would suggest something like a number of heated screens (like metal window screen) through which the air would flow or perhaps a long length of nichrome wire coiled inside the tube (think hair dryer).

Heating the tube would not give an efficient transfer of heat and would waste heat from the outside of the tube to ambient.

 

[jarity]

Transferring the heat to the air could indeed be a problem. You want a lot of surface area to the flowing air, the more the better. I would suggest something like a number of heated screens (like metal window screen) through which the air would flow or perhaps a long length of nichrome wire coiled inside the tube (think hair dryer).

Heating the tube would not give an efficient transfer of heat and would waste heat from the outside of the tube to ambient.

Thanks Crutschow,
I don't have a lot of expertise in this area but suspected as much. I will run a test using an array of such screens as well as a coiled wire inside the tube. I had thought of insulation on the exterior of the tube in any case.

 

[ronv]

You might think about attaching power resistors to a heat sink that the air has to flow thru. It will take some experiments to find out what surface area you need and of course you will need some outside feedback for incoming air temperature and outlet temperature.

**broken link removed**

 

[jarity]

You might think about attaching power resistors to a heat sink that the air has to flow thru. It will take some experiments to find out what surface area you need and of course you will need some outside feedback for incoming air temperature and outlet temperature.

**broken link removed**

Thanks Ronv,
this looks something that is cheap enough for me to experiment with. I found ( 2) 5 watt heatsinks smaller dia. on ebay. One of the problems is i don't know the materials/components available in this field. As i widen my knowledge of available components i am able to visualize a more efficient design. Thanx again for taking time to look this up and posting the link for me.