About this resource
Our health care heroes simply cannot 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 equipment as ventilators and positive pressure helmet / powered air purifying respirators (PPH/PAPR).
Whatever HEPA or ULPA filters, internal flow repartitions and garments are included in PAPR / PPH design, some major challenges are to assure the minimum of 20 litres / minute of purified air, to maximize the PAPR autonomy and to assure the easiness in control of the ventilated air volume and speed.
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 12VDC; ~130mA, 50x50x20mm; 9,68 cubic meters per hour. 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.
Bellow is our humble contribution - one very low cost, but effective design of PAPR / PPH blower flow controller. Intended for usage in conjunction with regular 5V power-bank and with compact, low flow, 12VDC blowers.
No Arduino, no RaspberryPI, no sensors, no internet of things - nothing fancy, just a basic and reliable hardware.
Blower controller schema
Blower controller PCB
Blower controller tests
We test the blower controller, AP3032 variant with 10uH/2.2A coil, powered from 5V 1A power bank.
We forced the SUNON GB1205PKV1-8AY blower up to 16.3V, having HEPA filter simulated by thick cotton pads. Maximum acquired flow is estimated at about 65-70l/min. and can be controlled to smaller flow very smoothly.
Measured blower maximum consumption was around 150mA and 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 other resources
Eagle schema and PCB files: here.
RESOURCES PROVIDED WITHOUT ABSOLUTELY NO WARRANTY! USE THEM AT YOUR OWN RISK!!!!