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Utilization of Landfill Gas

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					Breathing Machine
Design Requirements
   Provide/Remove 500cc of air
   Rate ≈ 15 breaths per minute
   Ability to vary volume of air, and rate

    Age (years)   Weight (kg)   Tidal Volume (cc)
     Child 10         33           200 - 270
    Teenager 17       55           330 - 440
       Adult          73           440 - 580
Existing Breathing Machines
   The need for artificial breathing mechanism has
    always been around with human history

   1896: O’Dwyer used a foot operated pump
    which blew air into patient’s lungs through a
    curved metal tube




                                 Existing Breathing Machines
Current Respirators
   Air-Shielded Electric Ventilators

   Mörch Piston Ventilators

   Bennett Respirators




                          Existing Breathing Machines
Air-Shielded
Electric Ventilators
   Blows atmospheric air into
    the lung using an electric
    powered blower that
    compresses and expands
    rubber bellows inside a
    rigid container

   Uses one-way valve

   Only works for inhalation




         Existing Breathing Machines: Air-Shielded Electric Ventilators
Mörch Piston Ventilators
   Uses a circular plate
    with a rod connected
    to a piston

   Motor provides force

   Circular plate controls
    volume

   For either inhalation
    or exhalation

              Existing Breathing Machines: Mörch Piston Ventilators
Bennett Respirators
   Operates with patient’s
    initiation

   Patient breaths in, low
    pressure causes spring to
    pop, and the valve opens
    since it is connected to the
    spring diaphragm

   Compressed air comes in
    until the pressure
    difference between either
    side of the valve becomes
    small

                    Existing Breathing Machines: Bennett Respirators
MUSSL Breathing Machine

  Inhalation
  Exhalation




               No tilting of the plate
Machined Components
 Casing
 Cam Supports
 Cams
 Beam and Slider
 Bellows Plate
    Weight & Sealing  Plexiglass


                Design Justification: Choice of Materials
How it works…
                       Fully-Compressed
                             (2 inches)




                       Fully-Expanded
                                   (12 inches)


                Neutral position
Expansion


                                        Exhaust Air
                                        from the lung

     Fresh Air


    Allowed
    Flow
    Direction


 Neutral position


                    Fresh Air trapped   Exhaust Air trapped
Compression

                   Trapped Fresh Air     Trapped Exhaust Gas
                   flows into the lung   escapes to ambient




Neutral position




Fully-Expanded
  Issues
Problems: 1) Difficulty in synchronizing 2 motors
          2) Severe sliding of outer beam along inner beam
             - leads to bending of the bellows




                                  Bending of the bellows




                                    Plate remains HORIZONTAL
    The Final Design
    3D-Model


       Bellows Guide




                                 1 Motor
       Timing Belt and Pulleys
Breathing Rate Control
   Variation of motor speed

   Method
     1. Resistive speed control
     2. PWM speed control




                Design Description: Breathing Rate Control
Resistive Speed Control




   R1 = motor, R2 = resistor
   Resistor reduces voltage delivered to motor
   Simple to implement
   Extreme inefficiency and possible danger


                     Design Description: Breathing Rate Control
PWM Speed Control




   PWM: Pulse Width Modulation
   Splits voltage supply into pulses and controls the
    pulse width, hence the total voltage
   Each pulse carries full voltage & torque


                      Design Description: Breathing Rate Control
PWM Circuit




          Design Description: Breathing Rate Control
Performance
 Provide/Remove      500cc of air

 Rate   ≈ 15 breaths per minute

 Ability   to vary volume of air

 Ability   to vary breathing rate

                                    Machine Testing
Integration with Lung Model

				
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