Our health care heroes simply can not work from home - they are in the coronavirus/covid19 response first line!
At this very moment, there are a lot of community initiatives addressing the challenging tasks of designing positive pressure helmet / powered air purifying respirators (PAPR).
In PAPR projects seen, I've noticed that in most of them was used quite big blowers having significant blow capacity, but also having big power requirements. This conduct to small autonomy and to heavy equipment, not even talking about costs.
Starting from minimum flow requirement of 20l/min [1.2m3/h] purified air and tacking a safety range of 2-2.5, I estimate the PAPR flow requirement target of 50l/min [3.0m3/h].
I looked around for some compact blowers and I chosen for this test SUNON GB1205PKV1-8AY | Ventilator: DC; blower; 12VDC; 50x50x20mm; 9, 68m3/h; 35dBA. This blower is rated with 1.5W having consumption ~120mA at 12V.
As second design criteria, I used the assumption of the usage of 5V power-bank - there are a lot of models available, some of them with storage as 10000mAh or even bigger.
To make the long story short, below is our humble contribution - one very low cost, but effective design of PAPR / PPH blower flow controller.Blower controller schema
We test the blower controller, AP3032 variant with 10uH/2.2A coil, powered from 5V 1A power bank.
We forced the GB1205PKV1-8AY blower up to 16.3V, having the HEPA filter simulated by thick cotton pads. Under such conditions, after some low resolution measurements, I personally estimated the maximum flow at about 65-70l/min., maybe more. The flow level can be controlled very smoothly adjusting the output voltage from the potentiometer.
Measured blower maximum consumption was around 150mA (at 16.3V) and blower controller efficiency between 82-86%.
Preliminary flow controller test (see cigarette smoke filtering - flow related), powered from LiPO battery, video here.
All those will be measured and tested, in real environment (PAPR helmet + blower 3D printed casing + HEPA / ULPA filters), by Pepe Peralta Guerrero from NEMO project / Timisoara, Romania (NEMO PAPR picture gallery here).
Blower controller EAGLE files here.
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