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By far the most unusual part of this rather neat product is the heater.  It is a very odd twist on standard technology, that allows greater heat transfer to the air.

The silica-gel cartridges seem to dry quite quickly for reuse due to the combination of heat and a low flow of air to drive the moisture out.

https://youtu.be/fHknZfdx9ME

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Inside a weird rechargeable silica gel dehumidifier

This very stylish dehumidifier branded Prem-I-Air (not a sponsor) consists of a base that blows a gentle stream of hot air that can either be used to dry shoes, or be used to recharge one of two silica gel moisture absorbing cartridges by drying it out. These could find use in a storage box for 3D filament or other items where you wanted to control humidity. The hot air flow ,means they dry relatively quickly compared to the very steamy versions that just contain an internal heater. The internal heater is very odd. Initially I thought it was a traditional resistive heater, because I got a slight whiff of that smell you get when the surface oil burns off a new heating element. But that might have been from the metal electrode plates on either side of a PTC (Positive Temperature Coefficient) block. What makes it really unusual is that the block is perforated with a grid of holes so the air can blow directly through it. I'd guess that allows more efficient heating of air, and a reduction in the amount of material needed. It also explains the air inlet filter material and the unused guides for a removable filter. The power supply is a fairly generic module for powering the 9V fan. Bizarrely, the red LED is NOT powered from that supply, but is run directly on the incoming supply instead, with a sleeved resistor and possibly a diode. The thermal fuse on the heater block is rated 5A with a trip temperature of 76 degrees C. This unit came from a UK eBay seller:- https://www.ebay.co.uk/itm/352580454594 There are other sellers selling them, but since they don't ship to the Isle of Man they won't get a link. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty. #ElectronicsCreators

Comments

Anonymous

I have that exact unit. I used it to keep the humidity in my gun safe down. Mine did not come with the boot drying attachment. It worked well, just needed to remember to pull it out and let it sit on the heater about once a week.

Anonymous

In Case anyone is looking for them it's spelt 'PREM-I-AIR' - let's get them before the Big Clive Price Hike kicks into action!

Keith W

Just remember when you "recharge" the desiccator canister, all that moisture within the desiccator canister is expelled in to the area you are drying the desiccator canister in.

Mike Hughes

Hi Kieth this is the ebay number I ordered it from : https://www.ebay.co.uk/itm/352580454594

Anonymous

Weight of new cartridge = 515 g Weight after heating = 475 g Definitely arrived damp then! Going to put one in telescope bag.

Anonymous

I had these same heating elements many years ago, but running on 12V. They are ceramic heating elements and act like PTC’s indeed. When the airflow stops, the temperature goes up and current drops. So they are somewhat self regulating, providing some safety.

Anonymous

Just 3D printing a container for loose silica that fits on the ebay dehumidifier. If everything fits I'll give it a test run and then upload a link with the STLs.

bigclive

My experiment of an adaptor and sawn-off drink bottle flopped (literally) with the heat.