A simple heater for preventing Hypothermia when administering IVs in the field.
Heating block is made from spent shell casings (found in abundance on the battle field/in conflict areas) cast into the desired shape using a 3D printed positive and casting sand.
Tube is layed down inside the groove and the lid is closed on top and locked in place.
PID controller is based on an Arduino Nano in the initial version, before a custom board is designed.
Power supply is meant as a DC input from a battery solar, probably solar charged.
Initial version is a PID controller.
Later, profiles for ramping up the temperature in steps when dealing with patients having a low core temperature can be added.
Got the block for testing the heat transfer of the tubing made.
I need to figure out how to transfer the heat from the heater while still having around 1 m of tubing inside it and avoid liquids. The easiest way would be to make a cool form, put the the tubing inside a container, add e.g. water and heat it up.
This adds unwanted fluids and more issues regarding daily use. E.g. evaporation, possibility of shorts etc.
So... today, I got my gritty mittens on an IV kit (Braun Intrafix) (and a blood kit) in order to get a better view of the task at hand..
Initially, I wanted the system to handle both IV (such as saline) and blood, but the flow rates are of a concern to me. Even professional equipment rolls up about 1 m (!!!!) of tube in order to create enough heating surface to heat the liquid and they even struggle with the ambient cooling of the last length of tubing.
Further input was given from a nurse related to the daily use and problems. This lead me to redesign the heating block based on the specifications of the tubing:
Diameter: 4.1 mm
Max pressure : 2 bar (current solution is a gravity fed system, so this is not important)
Max temperature: 40 C
I had hoped on setting a higher temperature for compensating for the ambient temperature based on the thermal resistance of the tubing (adjusted by the software), but I'll have to limit the maximum temperature to below 40 C.