Centrifuge Calibrator

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Centrifuge Calibrator
Group 18 Presents
BME 401 Preliminary Presentation

• Nicholas Adam Thaera
• Yu-Chen Su (Ray)
• Zhou-Yuan Zhang (Jimmy)
• Mentor Dr. Kurt Thoroughman

Wednesday, October 4, 2006
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Our Project Scope

• Engineering World Heath
• Provide means of verifying speeds of centrifuges
  for
• Underdeveloped countries
• Secluded regions
• Lower-income communities
• Cost less than 20 cents per unit

Centrifuge CalibratorMechanical or electrical
device for verifying the RPM of a centrifuge.
Must bereusable and applicable to a very wide
range of centrifuges. Separate devicesfor each
RPM calibration is acceptable.Relevant
additional specificationsCost lt1 in quantities
of 5
Engineering World Health. lthttp//www.ewh.org/gt
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Centrifuge Basics

• Spinning apparatus that uses centripetal force
• Objects feel centrifugal force

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Types of Centrifuges

• Laboratory centrifuge

• Astronaut spinner
• Ultracentrifuge

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Uses of Centrifuges

• Apheresis
• Donation of blood
• Plasmapheresis to alleviate Guillain-Barré
  syndrome1
• Leukapheresis to alleviate leukemia
• Sort cells and cell components
• Test drinking water2

1 National Institute of Neurological Disorders
and Stroke. "NINDS Guillain-Barre Syndrome
Information Page. 2 Taylor, Michael. "UV
Disinfection of Drinking-Water." MEUT.
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Problem of Centrifuges

• Centrifugation requires a specified centripetal
  acceleration (in g-forces).
• Knowing the rotational velocity, the acceleration
  can be calculated.
• However, turning the dial only changes power
  supplied to the motors.
• Inaccuracies
• Friction Heat loss occurs.
• Degradation Parts wear down.

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Problem of Centrifuges

• Why cant we just use the maximum speed?
• Test tubes break.3
• Cells are adversely affected.4

3 UltraClean Microbial DNA Isolation Kit.
Catalog No. 12224-S. 4 Sharma RK, Vemulapalli
S, Kohn S, Agarwal A. "Effect of centrifuge
speed, refrigeration medium, and sperm washing
medium on cryopreserved sperm quality after
thawing." Arch Androl. 1997 Jul-Aug39(1)33-8.
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Current Technology Simples Devices

• Mechanical Counter
• Tends to wear down
• Exhibits internal friction
• Completing a Circuit
• Difficult to make contacts
• Requires complicated
• setup

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Current Technology Optical Sensor

• Stroboscopic Effect
• Optic sensor detects N encounters per revolution

• Optical sensors are expensive!

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Current Technology Vibration Sensing

• Piezoelectric crystals
• Resonance

• Impractical - Requires massive computational
  power
• Unique for each device - Requires compiling
  statistical data

Song and Limin. "Virtual RPM sensor" United
States Patent 7,031,873.
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Current Technology Tachometer

• A tachometer is a device that measures the speed
  of rotation of a shaft, as in a motor. It
  displays this rate of rotation in RPM.
• There are many different types of tachometers.
• Main difference lies in the sensor of the
  tachometer.
• Hall effect sensor.

United States Patent 7,075,290 B2. Tachometer
apparatus and method for motor velocity
measurement. http//upload.wikimedia.org/wikipedia
/en/7/7e/Hall_sensor_tach.gif
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Our Choice

• Tachometer
• Cheap sold commercially
• Compact
• Reliable
• Simple to implement
• Parts
• Timing device
• Calculating circuit

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Design Concept

• Tachometer is placed within the space of the
  rotor and centrifuge case.

http//www.uspto.gov/web/patents/patog/week44/OG/h
tml/1300-1/US06960158-20051101-D00000.gif
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Preliminary Calculations

• Newtons Second Law
• Applied to Rotational Motion

Robert Fairbrother, Wendy Riddle and Neil
Fairbrother, Physics and Biochemical Engineering
3, Journal of Physics Education, Sept 2006,
p420-426.
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Preliminary Calculations

• G-force or Relative Centrifuge Force (RCF)

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Hall Effect
http//content.honeywell.com/sensing/prodinfo/soli
dstate/technical/chapter2.pdf
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Design Issues to Consider

• Display type digital vs analog
• Power source DC vs AC
• Connection of device from inside to the outside
  display
• System components

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Preliminary Specifications

• Completion of Design December 11, 2006
• Cost of Production 1 in quantities of 5
• Size 2cm2 by 3mm for circuitry, no limit for
  display
• Mass 50g
• Detection Range 0 15,000 RPM
• Power Supply DC power (battery) 1.5 V
• Compatibility Able to be installed on most
  laboratory benchtop centrifuges (80 of
  centrifuge models)
• Accuracy Reports RPM within 1
• Durability Robust and lasts 5 years
• Interface Analog pointer display
• Safety Adheres to safety guidelines
• Operating Temp Room temperature (25C 20C)
• Noninvasive Easily installed, requires 1 hour

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Preliminary Specifications

• Completion of Design December 11, 2006
• Cost of Production 1 in quantities of 5
• Size 2cm2 by 3mm for circuitry, no limit for
  display
• Mass 50g
• Detection Range 0 15,000 RPM
• Power Supply DC power (battery) 1.5 V
• Compatibility Able to be installed on most
  laboratory benchtop centrifuges (80 of
  centrifuge models)
• Accuracy Reports RPM within 1
• Durability Robust and lasts 5 years
• Interface Analog pointer display
• Safety Adheres to safety guidelines
• Operating Temp Room temperature (25C 20C)
• Noninvasive Easily installed, requires 1 hour

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Schedule Major Milestones
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Group Responsibilities

• Nick
• Preliminary Presentation
• Mechanics, Mathematics, 3D Modeling
• Jimmy
• Progress Presentation
• Electronics Circuits
• Ray
• Final Presentation
• Patent Research, Coordination

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Summary

• Centrifuge Basics
• Problem
• Scope
• Current Technology
• Our Choice
• Specifications
• Schedule
• Group Responsibilities

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References

• Images
• http//www.ewh.org/images/ewh.gif
• http//www.ktf-split.hr/glossary/image/centrifuge.
  gif
• http//www.gmi-inc.com/Genlab/Hettich Universal
  32R.jpg
• http//old.atlasaerospace.net/image/f_centr6.jpg
• http//www.gmi-inc.com/Genlab/beckman XL90.jpg
• http//content.answers.com/main/content/wp/en/thum
  b/7/7a/300px-Apheresis.PNG
• http//www.vimec.nl/images/stories/Technical-glass
  /Tubing_Broken_Cosm.jpg
• http//www.duanekeiser.com/Assets/venetianturpsbro
  ken.jpg
• http//enmco.thomasnet.com/ImgMedium/a1107.jpg
• http//www.trutrack.com/intech/SPST_circuit_diagra
  m.gif
• http//www.repairfaq.org/sam/vcrrsens.gif
• http//img.microsoft.com/whdc/images/archive/TempR
  ate7.GIF
• http//ccrma.stanford.edu/CCRMA/Courses/252/sensor
  s/img5.gif
• http//vestibular.wustl.edu/images/ear.jpg
• http//upload.wikimedia.org/wikipedia/commons/4/42
  /LightRefractsOf_comb-rows_of_ctenophore_Mertensia
  _ovum.jpg

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Questions

• Are there any questions?