Apparatus for the measurement of heat extraction coefficients

Claim 2

An instrument for the measurement of the heat extraction coefficient of solid bodies comprising a feeler constituted by two masses of good heat-conducting material, said masses comprising a central, measuring mass and a peripheral, protective mass surrounding the central mass and separated therefrom by a thin layer of a heat insulating medium, the two masses having coplanar surfaces for simultaneous contact with the body to be measured, first temperature measuring means for measuring the temperature of the measuring mass, second temperature measuring means for measuring the difference in the temperature of the two masses, displacement control means for placing the feeler in a position in contact with the surface to be tested and for separating the feeler from said position, electrical heating means surrounding the protective mass, power control means for controlling the power input to the heating means, and automatic means connected to said first and second temperature measuring means for triggering at appropriate times the following operational phases; the initial supply of power to the heating means of the protective mass for heating the two masses, the supply of further power to the heating means by the power control means in accordance with the difference in temperature of the two masses when the temperature of the measuring mass reaches a predetermined value, and operation of the displacement control means for placing the feeler in a position in contact with the solid to be tested when the temperatures of the two masses are substantially the same and for separating the feeler from said position, the contact surfaces each being covered with a layer of an elastomer filled with a powder of a body which is a good heatconductor.

Claim 3

An instrument for the measurement of the heat extraction coefficient of solid bodies comprising a feeler constituted by two masses of good heat-conducting metal, said masses comprising a central, measuring mass and a peripheral, protective mass surrounding the central mass and separated therefrom by a thin layer of a heat insulating medium, the two masses having coplanar surfaces for simultaneous contact with the body to be measured, first temperature measuring means for measuring the temperature of the measuring mass, second temperature measuring means for measuring the difference in temperature of the two masses, a supporting chassis for the feeler comprising displacement control means for placing the feeler in a position in contact with the solid to be tested with a predetermined force and for separating the feeler from said position, electrical heating means surrounding the protective mass and comprising a heating resistance, means for delivering electrical power to said heating resistance, means for controlling said power in accordance with the difference in temperature between the two masses when the temperature of the measuring mass as measured by the first measuring means reaches a predetermined value, an automatic means connected to said first and second temperature measuring means for triggering the following operational phases: the initial supply of power to the heating resistance of the protective mass for heating the two masses, the control of said supply of power to the heating resistance by said power controlling means in accordance with the difference in temperature of the two masses as measured by said second measuring means when the temperature of the measuring mass reaches said predetermined value, and the operation of said displacement control means so as to place the feeler in a position in contact with the solid to be tested when the temperatures of the two masses are substantially equal and to separate the feeler from said position.

Claim 4

An instrument for the measurement of the heat extraction coefficient of solid bodies comprising a feeler constituted by two masses of good heat-conducting metal, said masses comprising a central, measuring mass and a peripheral, protective mass surrounding the central mass and separated therefrom by a thin layer of a heat insulating medium, the two masses having coplanar surfaces for simultaneous contact with the body to be measured, first temperature measuring means for measuring the temperature of the measuring mass, second temperature measuring means for measuring the difference in temperature of the two masses, a supporting chassis for the feeler comprising displacement control means for placing the feeler in a position in contact with the solid to be tested with a predetermined force and for separating the feeler from said position, electrical heating means surrounding the protective mass and comprising a heating resistance, means for delivering electrical power to said heating resistance, means for controlling said power in accordance with the difference in temperature between the two masses when the temperature of the measuring mass as measured by the first measuring means reaches a predetermined value, an automatic means connected to said first and second temperature measuring means for triggering the following operational phases: the initial supply of power to the heating resistance of the protective mass for heating the two masses, the control of said supply of power to the heating resistance by said power controlling means in accordance with the difference in temperature of the two masses as measured by said second measuring means when the temperature of the measuring mass reaches said predetermined value, and the operation of said displacement control means so as to place the feeler in a position in contact with the solid to be tested when the temperatures of the two masses are substantially equal and to separate the feeler from said position.