Strap Adjustment

(Mock adjustment system for mask strap). The dial essentially controls the tension of all 4 straps by bringing two bridges closer together or further apart. A single cog and clutch component would set tension once adjusted and provide sensory feedback while performing the adjustment.

Exploring possibility of incorporating a living hinge on the main strap bridges for reduced protrusion and improved contact/comfort 

Update on Airflow Component

In discussion with hyperbaric technician: Johan Olivier, new useful information with regards to airflow has been made available and will have a significant impact on the technical attributes of the design in the following areas:


There will need to be a demand based mechanism in place for the expiratory airway due to the fact that air moving from a pressurized volume into a non-pressurized volume will cause a natural vacuum effect. Therefore the opening of the airway must be completely controlled by a positive pressure change in the mask (i.e expiring air). Otherwise the outlet will behave in the same way as a vacuum and will continue to draw air from the mask. 


26/07/11   

Side Configuration Valve Weight Test

A mock demand valve and diaphragm were attached to the fit test rig in order to identify any weight issues or changes in fit due to unbalance. The weight of this component was simulated as accurately as possible and equalled approximately 35 grams.

Result: 

Having this component positioned off centre - did not affect the fit or balance of the test mask in any way. Additionally, if the size of the diaphragm is further reduced it is likely that this component will have even less of an impact in these areas.

Additionally it was noted that downward vision was improved and a very minute portion of peripheral vision was affected on the right hand side. This can potentially be resolved further with testing and development in positioning and form. 

Basic Fit Test Rig

Basic fit test rig assembled using vacuum formed styrene and EVA foam. The purpose for building this rig was to evaluate the compliance of the seal over a range of different facial anthropometric profiles. 

Oxygen Inlet Configuration

Some basic mock-up layouts were used here to begin visualizing and collaborating key components of the mask. At this stage in the design process is it assumed that a circular diaphragm set up will be used to control the airflow of the mask - however further research into powered air supply circuits and alternative diaphragms will be conducted this week. This exercise was useful in beginning to ask questions around the configuration of airflow components and starting to establish a form language for the mask.  

Side Profile - Front Inlet/Outlet

Add caption

Inlet/Outlet - Same Side

Inlet/Outlet - Split

Update on Airflow System

New information gained through discussion with Performance Diver Technician: Allan Driscoll:

26/07/11

Demand valve systems work with compressed air supplies and can offer effortless breathing capability. Generally speaking, the larger the rubber diaphragm - the gentler the breathing work is.

The more energy demanding part of breathing through a circuit is the expiration phase - due to the fact that there is no force assisting you in moving the air. Where as, inspiring oxygen through a demand based supply is much easier due to the fact that the air is compressed so the resistance is less in between the point that the air is released - and your lungs.

The further the valve is positioned away from the mask - the more breathing resistance there will be due the fact that the distance to travel increases as well as the diameter of tube potentially becomes narrower. 

There may not need to be a demand based release mechanism as the air expired can exit through a one way valve provided there is as little resistance as possible.

There will only be a requirement for a mechanical valve if the expiratory limb is acting under vacuum.

Demand Based Airflow

This video basically demonstrates how pressurized oxygen can be supplied into a mask on demand - using lever and diaphragm components similar to that of a diving regulator. The advantage of using this system is improved oxygen efficiency and the amount of resistance the lever and diaphragm produce can be adjusted. My aim will be to achieve demand airflow that is gentle enough for effortless breathing during resting/sleeping.  

Molding Process

This phase was carried out to create a solid replica of a 50th percentile male head for further testing and experimentation with vacuum forming.
Process beginning: July 1st 2011