Supplementary Information for MADVent: A Low-Cost Ventilator for Patients with COVID-19
Journal Article - Open Access
CALIFORNIA UNIV SAN DIEGO LA JOLLA LA JOLLA
Pagination or Media Count:
Referring to Supplementary Fig. 1, there is a force, Fb pb x Ab Fs , on the lever due to contact with a pressurized bag, where pb is the pressure in the bag, Ab is the contact area between the bag and the lever, and Fs is the inherent force of the self-inflating bag. We assume the pressure in the bag is 40 cm H2O, the largest pressure anticipated to be used during normal operation. The contact area in the most compressed state can be approximated by the radius of the circular portions of the lever and the distance between these two, Ab 6.5 x 3 19.5cm2. The force produced by the self-inflating bag estimated by applying an increasing amount of static weight to the bag until the force of gravity on the weight overcomes Fs , approximately 10 N. The torque required about the hinge is estimated by Tarm AFb, presuming the force is perpendicular to the arm.