Austin FrazerEileen KobalAna Maria MaldonadoMarie Rohrbaugh
Moog Gas EvacuationSystems Design Review
The Team Austin Frazer
Role: Lead Engineer - Analysis Major: Mechanical Engineering
Eileen Kobal Role: Lead Engineer – Mixtures
of Gas Fluids Major: Chemical Engineering
Ana Maria Maldonado Role: Team Manager Major: Industrial Engineering
Marie Rohrbaugh Role: Project Manager Major: Mechanical Engineering
Problem Statement
To mass spectrometer
UUT
High pressure helium
High pressure helium
Fixturing/leakage similar to other side
Fixtures interface between AGT can and UUT
Fixture leakageUUT leakage
VOC to
VOE customer
rating
Mate with the
current softwar
e system
No extra procedur
e is required to make
the system
run
The system starts when
the test starts
Nitrogen
moves when
the system is
told to start
<5 sec between start of test
and equilibri
um
Reduce the
leakage into the can to 1% of
original value
No adjustment made to
original design
<100scc
/min of
Nitroge
n used
Maintenance plans
provided
Training
materials provided
cost of system is
<$10,000
time betwee
n mainten
ance cycles is
>30 days
FMEA performed
training
takes
<30 min
provide accurate test data 10 * * *
Preserve Vacuum 1 *
Reduce delay caused by false failures 7 * *
minimize increased cycle time 8 * * * * * *
user safety 12 * *
operator understands process 3 * * *
system is controlled transparently by the existing software 9 * *
minimize cost by balancing initial cost, maintenance cost, and consumable
materials6 * * * * * *
sturdy and robust system 11 * *
maximize time between maintenance cycles 4 * *
maintenance plans 5 *
maintenance can be accomplished with minimal money and time 2 * * *
Design Constraints Safety Contamination
Class 10,000 clean room. All products should comply to a strict cleanliness
certification Existing Fixture
Cannot modify inside of can Must be attachable to can
Gas Flow Nitrogen gas at 120psia available Vacuum at 1psia available
Pugh Diagram- Move/ Evacuate the Gas
Comparison Concept A B C D
small centrifugal pump to draw
out test gas
heating / cooling a
reservoir of inert gas to
draw out test gas
additional mass spectrometer at the vent draws
out test gassmall vacuum
pump
alternating drawing down
the test gas and pumping with a
flush gasCriteria Weight
Application elsewhere at Moog 1 0 -1 1 0 0Availability of resources 7 0 -7 -7 0 0Contamination possibility 9 0 0 0 0 0Cost 8 0 -8 -8 0 -8Durability (everyday use) 7 0 -7 0 0 0Effectiveness 9 0 -9 9 9 9Fits timeline 10 0 -10 0 0 0Long term benefits 5 0 0 0 0 0Maintainable 5 0 -5 0 0 0Meets space limitations 8 0 0 0 0 0Safety 10 0 0 0 0 0Works transparently with current system 9 0 0 -9 0 0 0 -47 -14 9 1
Pugh Diagram- Access the Gas
Comparison
Concept A B C
larger cavity for gas collection
modify vent geometry
fill vent with a viscous fluid to
prevent He from entering
have a different o-ring material so that the He
doesn't go through
Criteria Weight
Application elsewhere at Moog 1 0 0 -1 1
Availability of resources 7 0 0 -7 -7
Contamination possibility 9 0 0 -9 -9
Cost 7 0 -7 7 -7
Durability (everyday use) 7 0 0 -7 0
Effectiveness 9 0 9 -9 0
Fits timeline 10 0 0 0 0
Long term benefits 5 0 0 -5 0
Maintainable 5 0 0 -5 5
Meets space limitations 8 0 0 8 8
Safety 10 0 0 10 0
Works transparently with current system 9 0 0 -9 9
0 2 -27 0
Flexline to Nitrogen Source
Flexline to Vacuum Source
To vent
To large o-ring X2
Relief Valve
AN Fitting
2-way 2-position solonoid valve
Flexline to Nitrogen Source
Flexline to Vacuum Source
To vent
To large o-ring X2
Relief Valve 3-way 2-
position solonoid valve
AN Fitting
2-way 2-position solonoid valve
Analysis Performed – Simscape Parameters
Model Orings as Orifices
1 2 𝐾=𝜌
2𝐶𝑑2 𝐴2
𝛿𝑃=𝑃1−𝑃2
L = Approximate leak rate of the seal, std. cc/sec.F = Permeability rate of the gas through the elastomer at the anticipated temperature, std. cc cm/cm2 sec bar. (example: Butyl's permeability at 77oF with Acetylene is 1.26 x 10-8 std. cc cm/cm2 sec bar)D = Inside diameter of the O-ring, inches.P = Pressure differential across the seal, lb/in2 .Q = Factor depending on the percent compression and whether the O-ring is lubricated or dry (from figure 3 below)S = Percent compression on the O-ring cross section expressed as a decimal (i.e. for 20% compression, S = 0.20)
Diffusion
Diffusion Coefficient for 2
gasses
Diffusion Flux: Movement due to
Diffusion across an area
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