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Mechanical Specifications

Calculations
Calculations

Maximum Force Applied to Ambu-bag: 45 lbf

Assumed Motor Torque:

⁠

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:

⁠

Solving the equation for

⁠

Minimum Power Requirement: 28 Watts

Calculating the volume of the uncompressed Ambu-bag:

⁠

Where

⁠

are axes of the ellipsoid, so

⁠

for a 7" diameter Ambu-bag and

⁠

as an estimation of the Ambu-bag length

⁠

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

⁠

Calculating the work required to compress the Ambu-bag:

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Pressure is constant throughout compression because there is continuous flow.

Exaggerate

⁠

instead of

⁠

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

Calculating the required power to compress the Ambu-bag:

⁠

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

⁠

seconds.

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

⁠

, and the normal maximum required for an adult is

⁠

. The maximum volume output used in the calculations is

⁠

. This gives a built in factor of safety of around

⁠

. 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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CalculationsCalculations

Maximum Force Applied to Ambu-bag: 45 lbf

Minimum Power Requirement: 28 Watts

Calculations
Calculations