Cryogenic Freezing of Dissection Samples Gretchen Foltz Marie Meyer Kristy Wood and Jodi Zilinski BME 400 October 19th 2001 Client Professor Barry Ganetzky YoungHo Koh PhD Department of Genetics University of Wisconsin Madison Advisor Mitch Tyler Department of Biomedical Engineering Department of Rehabilitative Medicine University of Wisconsin Madison Overview Problem Statement Background Key Specifications Design Overview Components Cooling Mechanism Electrical Control Spray Chamber Final Design Preview Future Aspects Questions Problem Statement To design a device which is able to 1 Rapidly freeze biological specimens 2 Provide maximum vitrification 3 Preserve morphology Background Study of Synapses in Drosophilia Electron Scanning Microscope Requires New Fixation Techniques Key Specifications Preservation of Morphology Rate of Freezing Cost Regulation of Cryogen Flow Temperature and Pressure Design Overview Phase I Phase II Phase III Cooling Mechanism Overall Design Electronic Control Spray Chamber Integration And Testing Cooling Mechanism Primary Cryogen Liquid Nitrogen Secondary Cryogen Propane Component Elements Flow Rates Cryogen Volumes Length of the Copper Tubing P ro p a n e L iq u id N itr o g e n Thermo Calculations Amount of heat that must be removed for the sample to properly freeze specimen Amount of liquid propane needed to extract the heat in the sample Amount of liquid nitrogen needed to condense and cool the propane Length of copper tubing Thermo Calculations Volume of Liquid Propane 20ml Volume of Liquid Nitrogen 55ml Length of Copper Tubing 5cm Flask Dimensions 15x15cm Electronic Control S e n s o r y I n f o r m a t io n fro m S e c o n d a ry C ry o g e n T h e r m o c o u p le P r o p a n e I n le t P r o p a n e O u t le t C ir c u it P r o c e s s in g N O S e c o n d S o le n o id R e le a s e d YES YES S e c o n d a ry C ry o g e n 1 5 0 C N O LCD D is e n a b le S o le n o id V a lv e E n a b le S o le n o id V a lv e E n a b le S o le n o id V a lv e D is e n a b le S o le n o id V a lv e Spray Chamber C opper T u b in g Spray Mechanism Insulating Materials Vacuum Pump Solenoid Valves N o z z le F itt in g F u ll C o n e S p r a y N o z z le S a m p le Final Design Preview Spray Nozzle Copper Tubing 5 cm ID 0 4868 cm OD 0 9970 cm Copper Tubing 15 cm Flask 15 cm Copper Tubing 15 cm 1 cm Platform Flask 15 cm 10 cm Spray Chamber 5 cm Copper Tubing Platform Flask 15 cm 21 cm 15 cm Future Aspects Complete Engineering Drawings Build Prototype Testing Run a Design of Experiment to Optimize Cryogen Flow Make Necessary Adjustments to Design for Construction of Final Product Write Safety Manual for Operation Questions
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