©2013 Physio-Control, Inc. Confidential
Design History
Brainstorm, Pros and Cons, Top Design Ideas
©2013 Physio-Control, Inc. Confidential
Pros Cons• Eliminates most tubing • Not very exciting
• Simple • Have to make a connector
• Can design manifold similar to CasMed
• Separate module gives more flexibility
Pros Cons• All components completely integrated • Might be a little bulky
• Relatively small • Complex
• Interesting design
©2013 Physio-Control, Inc. Confidential
Pros Cons• Integrates all components • Not most compact design
• “Valve bundle” allows for easy storage of valves beneath pump
• Too much tubing
Pros Cons• Smallest design in size • Doesn’t completely integrate all
parts
• Integrates valves and circuit board
• Manifold design might be a bit difficult
• Separate pump allows more flexibility
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Top Three Initial Design Ideas
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Criteria for Picking Top three designs
Combined concepts Least Complex (can do in 10 weeks) Least amount of tubing Most compact
©2013 Physio-Control, Inc. Confidential
Criteria for Picking Top Design
Integrated connector can easily be added Neat appearance Compact system (length, width and height small
as can be) that can easily become completely integrated in the future
Interesting
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Top Design Idea Version 1.0
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Comments
Pros Cons • All ports in one area, minimized
friction between pump outlet and pressure sensor/cuff inlet
• Walls prevented access to the pump outlet
• Walls kept all parts contained • Walls added extra thickness
• Distance between sensor port and cuff port was acceptable
• Port to transducer was too close to pump, couldn’t put a tube completely over it.
• Port was designed as a barbed tube fitting to form a tight seal (tube ID 3/32”)
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Top Design Idea Version 2.0
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Comments
Pros Cons• Decreased size by removing
majority of walls and created a wall that can be inserted to keep bottom of the pump from sliding
• Two parts
• Repositioning sensor port (while maintaining the same port-to-port distance) allowed tube to fit completely over the ports
• No support for upper part of pump
• Added channels (details of design explained later)
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Top Design Idea Version 3.0
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Comments
Pros Cons• Added snap and clip for support
(removed all walls)• Clip too thin towards middle
(snapped)• More compact package • Snap too stiff
• Tooth of snap too long
• Slit on either side of snap too narrow
• Channel edges too sharp
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Top Design Idea Version 3.2
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Comments
Pros Cons Added strength to clip by adding triangular support
Tube doesn’t quite fit into pump and cuff outlet due to clip
Widened the slit ?
Rounded off all edges of channel ?
Redesigned snap ?
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Top Design Idea Version 4.0
Air channels
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Comments
Added seal around channels Removed extra materials Lengthened the snap (less load)
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Channel Design
Wanted to find channel width (b) and depth (a) that would minimize friction loss through channels
Defined a range for width and constant values for depth
Plotted data to find the smallest head loss.
©2013 Physio-Control, Inc. Confidential
Channel Design (Calculations)Inputs
384
* 0.965
3
0.17 – 0.27
0.1 / 0.3 / 0.7
*Flow rate was half of the one from rolling air pump data sheet.
Equations
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Channel Design (Calculations)
0.17 66636.22818 0.17 2742.232 0.17 259.0330.18 59254.41998 0.18 2425.62 0.18 227.30710.19 53033.9358 0.19 2160.642 0.19 201.0033
0.2 47743.46924 0.2 1936.684 0.2 178.96340.21 43206.53733 0.21 1745.719 0.21 160.32110.22 39286.60128 0.22 1581.586 0.22 144.41770.23 35876.69259 0.23 1439.497 0.23 130.7460.24 32892.05057 0.24 1315.682 0.24 118.910.25 30264.8125 0.25 1207.144 0.25 108.59770.26 27940.12765 0.26 1111.473 0.26 99.55990.27 25873.275 0.27 1026.717 0.27 91.59635
Depth (a) = 0.01 Depth (a) = 0.03 Depth (a) = 0.07
0.15 0.2 0.25 0.30
20000400006000080000
Varying Width (a=0.01)
Width (b) [in]
h_L
/ f [
in]
0.15 0.2 0.25 0.30
50010001500200025003000
Varying Width (a = 0.03)
Width (b) [in]
h_L
/ f [
in]
0.15 0.2 0.25 0.30
100
200
300
Varying Width (a=0.07)
Width (b) [in]
h_L
/ f [
in]
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Channel Design (Results)
Optimal depth: 0.07 in Optimal width: 0.27 in : ~91.6 in Velocity: ~51.1
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Snap Design
Used it to secure bottom of pump as a replacement for the wall.
Takes up less space Had to make sure strain was below 1.3% to
prevent my snap from breaking
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Snap Design (Calculations)
Note: Formulas based on Snap Fit Design Manual from BASF Chemical Company‐
Inputs:
Outputs:
Strain is about 0.8% which is less than 1.3% and less than the limit (typically 3-6%) recommended in design guides for PC/ABS.
©2013 Physio-Control, Inc. Confidential