1. ©2013 Physio-Control, Inc. Confidential
Design History
Brainstorm, Pros and Cons, Top Design Ideas

2. ©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

3. ©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

4. ©2013 Physio-Control, Inc. Confidential
Top Three Initial Design Ideas

5. ©2013 Physio-Control, Inc. Confidential
Criteria for Picking Top three designs
 Combined concepts
 Least Complex (can do in 10 weeks)
 Least amount of tubing
 Most compact

6. ©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

7. ©2013 Physio-Control, Inc. Confidential
Top Design Idea Version 1.0

8. ©2013 Physio-Control, Inc. Confidential
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”)

9. ©2013 Physio-Control, Inc. Confidential
Top Design Idea Version 2.0

10. ©2013 Physio-Control, Inc. Confidential
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)

11. ©2013 Physio-Control, Inc. Confidential
Top Design Idea Version 3.0

12. ©2013 Physio-Control, Inc. Confidential
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

13. ©2013 Physio-Control, Inc. Confidential
Top Design Idea Version 3.2

14. ©2013 Physio-Control, Inc. Confidential
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 ?

15. ©2013 Physio-Control, Inc. Confidential
Top Design Idea Version 4.0
Air
channels

16. ©2013 Physio-Control, Inc. Confidential
Comments
 Added seal around channels
 Removed extra materials
 Lengthened the snap (less load)

17. ©2013 Physio-Control, Inc. Confidential
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.

18. ©2013 Physio-Control, Inc. Confidential
Channel Design (Calculations)
Inputs
𝐺𝑟𝑎𝑣𝑖𝑡𝑦 (𝑔) [𝑖𝑛/𝑠2] 384
*𝐹𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 (𝑞) [𝑖𝑛3/𝑠] 0.965
𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑐ℎ𝑎𝑛𝑛𝑒𝑙 (𝐿) [𝑖𝑛] 3
𝑅𝑎𝑛𝑔𝑒 𝑜𝑓 𝑊𝑖𝑑𝑡ℎ (𝑏) [𝑖𝑛] 0.17 – 0.27
𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡 𝐻𝑒𝑖𝑔ℎ𝑡 𝑣𝑎𝑙𝑢𝑒𝑠 (𝑎) [𝑖𝑛] 0.1 / 0.3 / 0.7
*Flow rate was half of the one from rolling air pump data sheet.
Equations
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 (𝑣) 𝑞
𝑎𝑏
𝐻𝑦𝑑𝑟𝑎𝑢𝑙𝑖𝑐 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 (𝐷ℎ) 2𝑎𝑏
𝑎 + 𝑏
𝐻𝑒𝑎𝑑 𝐿𝑜𝑠𝑠
𝐹𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑓𝑎𝑐𝑡𝑜𝑟
ℎ 𝐿
𝑓
𝐿𝑣2
2𝐷ℎ 𝑔

19. ©2013 Physio-Control, Inc. Confidential
𝑊𝑖𝑑𝑡ℎ (𝑏) ℎ 𝐿/𝑓 𝑊𝑖𝑑𝑡ℎ (𝑏) ℎ 𝐿/𝑓 𝑊𝑖𝑑𝑡ℎ (𝑏) ℎ 𝐿/𝑓
Channel Design (Calculations)
0.17 66636.22818 0.17 2742.232 0.17 259.033
0.18 59254.41998 0.18 2425.62 0.18 227.3071
0.19 53033.9358 0.19 2160.642 0.19 201.0033
0.2 47743.46924 0.2 1936.684 0.2 178.9634
0.21 43206.53733 0.21 1745.719 0.21 160.3211
0.22 39286.60128 0.22 1581.586 0.22 144.4177
0.23 35876.69259 0.23 1439.497 0.23 130.746
0.24 32892.05057 0.24 1315.682 0.24 118.91
0.25 30264.8125 0.25 1207.144 0.25 108.5977
0.26 27940.12765 0.26 1111.473 0.26 99.5599
0.27 25873.275 0.27 1026.717 0.27 91.59635
Depth (a) = 0.01 Depth (a) = 0.03 Depth (a) = 0.07
0
20000
40000
60000
80000
0 0.05 0.1 0.15 0.2 0.25 0.3
h_L/f[in]
Width (b) [in]
Varying Width (a=0.01)
0
500
1000
1500
2000
2500
3000
0 0.05 0.1 0.15 0.2 0.25 0.3
h_L/f[in]
Width (b) [in]
Varying Width (a = 0.03)
0
100
200
300
0 0.05 0.1 0.15 0.2 0.25 0.3
h_L/f[in]
Width (b) [in]
Varying Width (a=0.07)

20. ©2013 Physio-Control, Inc. Confidential
Channel Design (Results)
 Optimal depth: 0.07 in
 Optimal width: 0.27 in

ℎ 𝐿
𝑓
: ~91.6 in
 Velocity: ~51.1
𝑖𝑛
𝑠

21. ©2013 Physio-Control, Inc. Confidential
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

22. ©2013 Physio-Control, Inc. Confidential
Snap Design (Calculations)
Note: Formulas based on Snap‐Fit Design Manual from BASF Chemical Company
Inputs:
𝐿 = 0.8 𝑖𝑛
𝑏 = 0.45 𝑖𝑛
𝑡 = 0.06 𝑖𝑛
𝐸 = 360,000 𝑝𝑠𝑖
𝑌 (𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡) = 0.1 𝑖𝑛
Outputs:
𝑘 = 10.5
𝑙𝑏𝑓
𝑖𝑛
𝑃 = 1.05 𝑖𝑏𝑓
𝐸 = 0.008625
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.

23. ©2013 Physio-Control, Inc. Confidential