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Heated Lavage

Heated Lavage

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Heated Lavage

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  1. Heated Lavage Joe McFerron, Justin Miller, and Ashley Danicic Dr. Dinakar Golla, M.D Linda Huckenstein , R.N

  2. Background Information • Lavages are most frequently used to remove debris from an organ or cavity with repeated injections of a solution. • The solution (saline) is often heated • to increase circulation to the area • reduce the risk of infection • and to increase the comfort of the patient

  3. HeatExchanger Bulky More expensive Must rely on internal pump in the heat exchanger to propel the solution to the lavage device. Microwave cannot control the temperature of solution PVC IV bag deforms at 135-180 degrees F Solution immediately begins to cool, must be reheated again Methods

  4. Group Goals • To design a device that when mounted onto the IV bag, can control and measure the temperature of the solution • Heater must heat solution to desired temperature, it must be flexible, small, and capable of heating solution quickly • Choose insulation for heater which is resistant to chemicals, water, and other liquids. • The thermocouple • must be small enough to fit into one of the IV’s ports. (~0.24 in), • capable of immersion in fluids, but also must not let solution leak from port. • Fast and accurate response • hermetically sealed

  5. Individual Goals • Research heater options • Etched Foil-etched foil resistive element • Pros: more economical in small heaters, thin, very flexible, transfer heat more efficiently over larger surface area, heaters stay cooler to the touch, run higher wattages, insulation life is 10x greater, uniform heat patterns, • Cons: heating element less durable, not as economical if manufactured • Resistance Wire- wire elements, • Pros: more economical in large sizes/ manufacturing, durable, lower leakage current, withstand repeated flexing, uniform heat patterns • Cons: thick , reduced watt densities • Research insulation options • Kapton • Silicone Rubber • All-Polyimide (AP) • Mica • Update Design history file

  6. Achievements to Date • Procured 2 lavages for testing • Designed heater • determined approximate heater size, temperature range, Max. resistance density, power, lead locations and size • Heater will be galvanized to mating parts. • 5 minute warm up time • Heater wraps around circumference of IV bag and clamped into place. • Contacted several custom heater manufacturers • Considering thermocouple • Selected Kapton insulator • Excellent dielectric strength, resistant to most acids, solvents, and bases, can be made for immersion in fluids.

  7. Completed heater design • Maximum heater thickness (with foil backing): • Over element: 0.4 mm • Over Leads: 1.4 mm • Kapton Insulator: 0.03-0.05 mm • Temperature range (-200 C -200 C) • Lead Wires: 0.141 mm^2

  8. Work to Do • Finite Element Analysis on Heater in CosmosFloWorks • (This week) • Decide on Thermocouple • (Mid February) • Decide temperature controller • (Mid February) • Order heater and thermocouple prototypes. • (February) • Test these protypes • (March-April)

  9. Criteria For Heater Success • Heater heats solution to specific temperature • Heater stays securely on IV bag • Completed device is easy to mount onto bag • Heater is portable, small, and flexible

  10. Sample Calculations • Warm up Power: • P(watts)=mCp(tf-Ti) / t • 1000(g)*4.19(J*g/C)*(40 C-25 C) / (600s)= 104.75 • 125.7 W with heat loss • Conduction Loss: • Pcd=KA(Tf-Ta) / 3.412*L • 4.08 Btu*in/ft^2/F/hr*(12.9 ft^2)*(104F -77F) / 3.412*15.24 in=27.33W • Radiation Loss: • Pr= E*A(0.173x10^(-8))*(Tfr^2-Tar^4) / 3.412 • 0.98(.1713*10^(-8))*((104+460)^4-(77+460)^4) / 3.412 = 8.87 W