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Calculations

Maximum Force Applied to Ambu-bag: 45 lbf

Assumed Motor Torque:

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Tension in rope:

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Taking the moment about hinge when the compression bar is horizontal and the tensioning rope is perpendicular to bar:

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Solving the equation for

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Minimum Power Requirement: 28 Watts

Calculating the volume of the uncompressed Ambu-bag:

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Where

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are axes of the ellipsoid, so

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for a 7" diameter Ambu-bag and

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as an estimation of the Ambu-bag length

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Exaggerating the true compression as approximately compressing the Ambu-bag to the shape of an oval plate:

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Calculating the work required to compress the Ambu-bag:

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Pressure is constant throughout compression because there is continuous flow.

Exaggerate

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instead of

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(This does not account for silicone rubber material properties of Ambu-bag.)

Calculating the required power to compress the Ambu-bag:

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At a maximum frequency of 30 BPM (breathes per minute), with an Inhale:Exhale ratio of 1:3, the ventilator must compress every

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seconds.

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The maximum tidal volume output of the Ambu-bag required for respiration is around

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, and the normal maximum required for an adult is

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. The maximum volume output used in the calculations is

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. This gives a built in factor of safety of around

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. This power requirement is close to the MIT E-Vent specified requirement, with a similar factor of safety. (Source:

https://e-vent.mit.edu/mechanical/power-calculation/

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)

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