According to Gordon Rose, senior industrial designer for ARC’TERYX, he tested various air blowers, including ducted fans, centrifugal blowers and mixed flow blowers, with and without venturi systems as proof of concept work. However, since he had no formal background in rotor engineering, Rose needed a partner to help optimize the blower system. This led him to ADT.
“I was initially drawn to ADT when looking for design software to help me design the blower”, said Rose. “But, after contacting ADT and discussing the complexity of the project, we decided a much better solution was to use ADT’s design expertise and have them optimize the blower system rather than to acquire their software system”.
Using the 3D Inverse Design methodology in ADT’s TURBOdesign Suite software, ADT’s engineers examined the parameters of ARC’TERYX’s required performance characteristics, the available power and all the blowers Rose had experimented with before offering ARC’TERYX definitive advice on the most appropriate blower technology - a centrifugal blower.
“Our system requires two aspects to be optimized that are at opposite ends of the performance spectrum - relatively high pressure for initial deployment of the airbag from the backpack and then maximum air-flow to fill the bag quickly with no back-pressure”, said Rose.
Because of the two opposing goals, the use of 3D Inverse Design methodology was justified and required to find an optimal design. Rose added, “The other factors critical to our system were maximum efficiency and minimum size. Both have implications beyond the blower design as the weight and power requirements for the battery are critical to the overall weight of the backpack system, and the size of the blower dictates the space requirements. The use of ADT’s 3D Inverse Design methodology ensured we could optimize all these factors and be 100% confident before committing to the final design, tooling costs, etc”.
ARC’TERYX executives had concerns about the injection moulding tooling costs, so they wanted to try several design concepts. ADT quickly provided design alternatives for testing these concepts.
All the development work was done using 3D prototype impellers or existing components with the assumption that if they worked well enough then a future version could be refined and improved upon for size and efficiency. The testing phase resulted in good data for available power, torque and rpm, though the impellers were not optimized.
After establishing the project parameters and discussing the various concerns for manufacturing and other variables like motor power, ARC’TERYX had ADT provide digital files for several potential design solutions for the impeller and housing. Rose converted these into 3D mechanical drawings and built rapid prototypes and cast polyurethane prototypes to test the blowers in the company’s airbag system.
Rose collected the data such as power loading, rpm, inflation times and pressure achieved and then discussed the geometry with the tool and die maker (for injection moulds). Rose provided feedback to ADT along with comments on how to improve the final product. ADT used the feedback to redefine geometries and proposed alternate solutions.
Through several design iterations they all arrived at the final solution, at which point Rose made a number of prototype systems for bench testing and for field evaluation in the full airbag backpacks prior to committing to tooling and final design of the other components in the system (DC motors, batteries, controllers).
ARC’TERYX proved the system was workable and applied for international patents covering the entire technology platform. After this, the team optimized all aspects of the technology platform, including the battery system (or alternative), the electronic control system and the air blower.