Thermal conductivity apparatus

Abstract

Abstract THIS INVENTION COMPRISES AN APPARATUS EMPLOYING THERMOELECTRIC HEAT PUMPS TO EFFECT THE REQUIRED LEVEL OF TEMPERATURE CONTROL NECESSARY TO PROVIDE AN ADEQUATE MEASUREMENT OF THE THERMAL CONDUCTIVITY OF INSULATING FOAMS. THE METHOD OF ESTABLISHING A FIXED THERMAL DIFFERENCE ACROSS THE SAMPLE IS ACCOMPLISHED BY PLACING THE SAMPLE BETWEEN TWO SURFACES WHOSE TEMPERATURES ARE ACCURATELY CONTROLLED. THE COLD PLATE TEMPERATURE IS ACCURATELY SET AND CONTROLLED BY A THERMOELECTRIC HEAT PUMP DRIVEN BY A HIGH GAIN PROPORTIONAL CONTROLLER. THE HOT PLATE IS ALSO OPERATED AT AN ACCURATELY CONTROLLED TEMPERATURE, HEAT BEING SUPPLIED FROM A CLOSE-COUPLED PROPORTIONALLY CONTROLLED LOW MASS HEATER. THE HEAT FLOW THROUGH THE SAMPLE IS MEASURED WITH A HEAT FLOW TRANSDUCER WHICH PRODUCES AN EMF THAT IS PROPORTIONAL TO THE HEAT FLOW PER UNIT TIME AND AREA THROUGH THE FOAM. THE EMF THUS DERIVED IS VOLTAGE DIVIDED BY A SLIDE WIRE WHICH IS MECHANICALLY COUPLED ANALOG CORRECTIONS ARE MADE TO PROVIDE A SIGNAL FOR DIRECT DIGITAL READ-OUT OF "K."

Inventors

• 👤 John V Goode Jr
• 👤 Zaxk J Moore

Bibliographic Details