DESIGN
Thermal Conductivity Measuring Device
There are multiple methods to measure thermal conductivity. Methods are researched and the best method is chosen. The most optimum technique for measuring thermal conductivity is determined from analyzing the requirements for the device, cost, available resources. The methods researched and analyzed include; Steady state longitudinal heat flow method, Thermistor with pulse heat input, Heated thermo-couple method, and Thermistor with step temperature change. The technique chosen most resembles the heated thermistor with step temperature change technique.
ANALYSIS
Analysis is done to provided design parameters to create a successful design. Test time, resolution, material, product selection, and dimensions for the device is determined within the analysis process. Components requiring analysis include the thermistor, circuity housing, probe house and electrical system. Requirements for device will also be analyzed. Utilizing the product requirements thermodynamic, statics, and strength of materials design parameters can be determined.
Analyses;
Resistivity required to achieve 5% error
Maximum axial load of probe (occupational limit)
Thickness required for handle
Outer diameter required for probe housing
Screw diameter
Equivalent screw length engagement
Bit spec required for circuit board
Weight
Resistor to complete Wheatstone bridge.
Power supply to heat up thermistor
Required thickness of revised probe housing with hole
RC8 fit tolerancing for probe housing and handle
Thiessen voltage to resistance of thermistor
Requirements;​
- The requirements for this project include:
The unit can weigh no more than 20lbs
Must fit in a 18x13x10 box
Measurement time must take less than 15 minutes
Takes less than 45 mins to prep for testing.
Device must record accurately less than 5% error
