WHIRLPOOL CAPSTONE
STEAM GENERATION
PROJECT
TEAM: JEFF PHILIPPART, TEAM MEMBER NAMES
REMOVED
INITIAL DESIGN CONCEPTS
• Ultrasonic Humidifier
• Uses piezoelectric transducer to vibrate water droplets into
vapor.
• Produces “Cool Mist” immediately with no warm up time.
• Boiler
• Steam exits boiler after it reaches vaporization point.
• Impeller Humidifier
• Fan pulls water droplets through diffuser and into
atmosphere.
• “Invisible Mist” exits fan after water moves through diffuser
TESTING METHOD
• Gauze
attached to
thermocouple
as wet bulb
• The end of the
gauze was
placed in a
measuring cup
of water
• Second
thermocouple
used as dry
bulb
• The
convection fan
was run
continuously
PERFORMANCE AT 350° F
Relative Humidity versus Time at 350F
3.000
Relative Humidity(%)
2.500
2.000
1.500
no added
humidity
boiler
1.000
humidifier
0.500
0.000
0
2
4
6
8
Time(mins)
10
12
14
16
• The boiler
performed
the best at
350
degrees
Fahrenheit
PERFORMANCE AT 450° F
Relative humidity vs. time at 450F
1.200
1.000
Relative Humidity(%)
• The
humidifier
performed
the best at
450
degrees
Fahrenheit
no added
humidity
0.800
boiler
0.600
humidifier
0.400
0.200
0.000
0
5
10
time(min)
15
20
FMEA
Product
Funtion
Potentional Failure Mode Severity
Potention Root Cause
Occurance Rating
Corrective Actions
10
Hard Water
5
Customer Instructions: Deionized Water
10
System Flood
4
Use Corrosion Resistant Material
Tubing Leak
10
Material Wear
5
Use Stronger Heat Resistant Tubing
Cloged Transducer
10
Hard Water
5
Customer Instructions: Deionized Water
10
Material Corrosion
5
Use Corrosion Resistant Material
10
Resevoir Scaling
5
Heating Element in Water Resevoir
Tubing Leak
10
Material Wear
5
Use Stronger Heat Resistant Tubing
Overflow
10
Customer Error
6
Add Failure Valve
Customer Getting Burnt
10
Hot Water Draining
5
Auto Valve Drains When Cooled
Tranducer Fail
Ultrasonic Humidifier
Provide Steam To Oven
Cavity
Boiler Reserve Leak
Steam Boiler
Drain Valve
Provide Steam To Oven
Cavity
Drain
BOILER CONSTRUCTION
CONSIDERATIONS
• Recycles no parts from the steam generator
used in performance testing.
• Water reservoir will maximize the surface
area that will be exposed to the external
heating plate constructed from welded
aluminum .
• Heating plate will be constructed from scrap
range top element received after the oven
breakdown
• Electric coils will be removed and set in a
non-conductive base plate
• Coil path will be milled into the base plate.
• Glass plate will be cut to size and attached
to the base plate with an adhesive.
• Steel brackets will be bent to mount the
prototype behind the oven cavity.
• Rubber top will be purchased and hole for
nozzle drilled
• Boiler construction considered “reasonable”
and scores middle value of 2 on Pugh
matrix.
HUMIDIFIER CONSTRUCTION
CONSIDERATIONS
• Many recycled parts from the
ultrasonic humidifier used
during the performance testing
• Wires on the humidity level
switch and led light will be
stripped and extended
• Switch and LED light will be
mounted below stove knobs
• Re-designed body will be 3-D
printed and contain humidifier
components.
• Mounting brackets will be
made from bent steel to
secure body behind oven
cavity
• Humidifier construction is
considered “good” and scores
best score of 1 on Pugh matrix
COST
Humidifier
Boiler
Boiler Design Cost
Humidifier Design Cost
part
size/type/quantiy
part
Cost
size/type/quantiy
Cost
transformer
1
$6
nichrome wire
5 ft
$5
transducer
1
$4
aluminum body
1
$7
small fan
1
$2
switch
1
$2
3 ft
$1
rubber top
1
$3
circuit board
1
$4
water sensor
1
$1
heat resistant tubing
1
$1
led light
1
$2
water resevoir
1
$2
switch
1
$2
drain valve
1
$1
water resevoir
1
$2
water sensor
1
$1
body
1
$5
led light
1
$2
drain valve
1
$1
lock
1
$1
wiring
TOTAL
$30
TOTAL
$25
RELIABILITY
Quality of
Steam
Warm-up Time
Quality of Food
Control
Maintenance
Ultrasonic Humidifier
Impure water mist could be directly
injected into the oven cavity if water in
the reservoir is contaminated.
Customer Introduction is needed.
Water mist is formed as soon as the
system is turned on. Users can find out
whether the humidity feature is properly
working or not immediately.
Cold mist injected into the oven cavity
could cause a temperature fluctuation
which affects the quality of food.
Steam Generator
As the water goes through the boiling
process, there is less possibility of impure
steam being injected to the oven
cavity.
It takes about 12 minutes for boiling
water. But the oven also needs time for
pre-heating.
Comparison
Steam generator has less
possibility of having
contamination issues.
As fewer components are required for
installing a mist generating unit into the
oven, there are less maintenance issues.
Components such as a transducer and a
fan are easily replaceable. There are
also scaling issues.
Additional Heating components are
required for boiling water. Same as an
ultrasonic humidifier, there are scaling
issues. (run vinegar through it to clean it)
Ultrasonic humidifier requires
less effort for maintenance. But
both systems has common
scaling issues which affects the
life time of each system greatly.
Ultrasonic humidifier works
much faster than steam
generator. Ultrasonic humidifier
requires no warm up time.
As the heated steam is injected into the Ultrasonic humidifier is
oven cavity, there are less food quality expected to have a higher
issues due to temperature.
possibility of food quality issue.
But further testing is required to
verify it.
The flow rate can be easily controlled by The flow rate can be easily controlled
Flow rates of both systems can
adjusting the vibration speed of the unit. by adjusting the electric current with a be easily controlled by users.
Users can easily adjust the flow rate with knob.
a knob.
PUGH MATRIX
Pugh Matrix
Design
FMEA
Humidifier
1
Boiler
3
1-good
2-reasonable
3-poor
Cost
3
1
Performance Application Construction Reliability Usability
2
1
1
2
1
2
2
2
2
1
TOTAL
10
11
Water Entrance
3-D DESIGN
Vapor Exit
Fan Entrance
Water Drain
Circuit Board
Transducer
Water Sensor
Flow onto Transducer
Plunger
Path for fan flow
Low Water LED
Switch
Water Entrance
Vapor CAVITY Entrance
Body
Transformer
Regulator
DESIGN MODIFICATIONS
Extended
Roof
Angled
Vapor Exit
Vapor Exit
Ramp
DESIGN MODIFICATIONS
Altered
Dimensions
Floating
Magnet
LED
COMPLETE PROTOTYPE
Switch
Prototype Water Inlet
• Oven front (above)
• Prototype and connection
mounted on the oven back (right)
Prototype Water Reservoir
TESTING RESULTS AT 350°F
% Moisture by volume vs. time at 350F
% Moisture by volume
30.0
20.0
10.0
0.0
0
2
4
6
8
Time(min)
10
12
14
16
TESTING RESULTS AT 400°F
% moisture by volume vs. time at 400F
75.0
% Moisture by volume
60.0
45.0
30.0
15.0
0.0
0
2
4
6
8
Time(min)
10
12
14
16
TESTING RESULTS AT 450°F
% moisture by volume vs. time at 450F
75.0
% moisture by volume
60.0
45.0
30.0
15.0
0.0
0
2
4
6
8
Time(min)
10
12
14
16
BREAD TESTING METHOD
• Oven pre-heated to
350 °F
• Thermocouple placed
approximately 2 inches
into dough
• Desired Thermocouple
reading of 93° C (200
°F)
BREAD TESTING RESULTS
With
Prototype
Normal
Oven
Conditions
MODIFICATIONS AND SUGGESTIONS
FOR FUTURE IMPROVEMENTS
Product
Funtion
Potentional Failure
Mode
Tranducer Fail
Humidifier Prototype
Provide Steam To
Oven Cavity
Tubing Leak
Cloged Transducer
Severity
Potention Root Cause Occurance Rating
Corrective Actions
10
Hard Water
5
Customer Instructions: Deionized Water
10
System Flood
4
Use Corrosion Resistant Material
10
Material Wear
5
Use Stronger Heat Resistant Tubing
10
Hard Water
5
Customer Instructions: Deionized Water
10
Material Corrosion
5
Use Corrosion Resistant Material
• Design permanent water reservoir and water inlet
• CNC Machine components from heat resistant plastic
• Design smaller fan and scale down body size to accommodate limited
space at oven back
• A larger piezoelectric plate could increase the water vapor production
• Add required circuitry to central board to eliminate humidifier board,
transformer, and regulator
• Move LED and switch for better physical appearance