156B Week 4
Overview of Status of Analysis, Design, Fabrication, Tests, etc.
3D printing single valve for testing
Implementing soft rubber tubing into device
Accomplishments from Previous Week
Valve CAD has been completed
Extensive testing done to verify viability of valve design over needle valves
Evaluated channel pressures and determined pressure drop was non-negligible
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Testing device with 3D printed valve (Josh)
Implement electronics
Make adjustments if necessary
If all goes well, make 2 more
Complete a first draft of the report (Obed, Basil)
Continue developing servo control code and design low pass filter (Jeffrey)
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
All comments via Zoom (4/22)
Data should be plotted more clearly
Rename the legend in the plot comparing needle valves and compression valve
Change bar plots for channel data to be a single bar with standard deviation added
Don't need to continue with 10 channel design, instead go with 4 and measure the whole range
Currently 50 mm of Hg, might change to 100 mm of Hg
Max shear stress of 0 - 30 Dynes/cm^2
Max flowrate of ~30 mL/s
Begin finalizing 4 channel device
Concerned with attaching valves to device
Explore mounting solutions like high heat velcro, printing custom mounts, etc
Left space on bottom of valve for attachment points
Might want to consider building a heat chamber to test the device at temperature
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Comments via email (4/20)
Valve/Channel Report
The steady state data is noisy
Working on designing a low pass filter to condition pressure sensor output
More clearly label steady state data for channel
In future presentation will put the three tests on separate subplots
The variation in pressure is due to sensor sensitivity because 1 psi = 51 mm of Hg
Valve/Channel Presentation
Clearly state conditions for dependence of pressure variation on tube diameter
Plots are still confusing
Consider swapping "turns" and "% open" on plots
Clearly indicate which valve is being changed
Big problem is in clearly defining our experiments
Which valve/channel is being tested and what variables are being studied needs to be made clear
Add slide describing the flowrates
Elaborate on the valve comparison slide
Really point out why needle valves suck (very high P is too high for the cells to survive, even when fully open)
Suggests verifying the maximum clamping needed to attain desired inlet pressures
Also suggests expanding experimental setup to encompass all valves of the same type
Use a clamp on all three valves and tune to achieve desired pressures
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
n/a
Risks and Areas of Concern
Mounting valve to device might make device overly bulky and cluttered
Resources or Information Required but not Available
n/a
Schedule
Successfully regulate pressure with one valve
Overhaul design for 4 channels
Budget (list amount spent and amount remaining)
~$300 spent, ~$2-300 remaining
Progress on Report and Webpage
Updating internal site
Should upload CAD files for first iteration of valve design