Apparatus for the high temperature testing of dielectric materials

Claim 1

IN AN APPARATUS FOR THE HIGH-FREQUENCY DIELECTRIC TESTING OF SPECIMEN DISCS, THE COMBINATION COMPRISING AN ELECTRICALLY CONDUCTIVE CYLINDRICAL CASING, A FIXED STEM ELECTRODE COAXIAL WITH THE CASING HAVING A PLANE END FACE, EXTENDING INTO THE CASING FROM ONE END THEREOF TO FORM THEREWITH A CONSTANT-IMPEDANCE COAXIAL-LINE PORTION, A SECOND STEM ELECTRODE ALSO COAXIAL WITH THE CASING AND ALSO HAVING A PLANE END FACE, EXTENDING INTO THE CASING FROM THE OTHER END THEREOF TO FORM THEREWITH A FURTHER COAXIAL-LINE PORTION, MEANS FOR SO SUPPORTING THE SECOND ELECTRODE AS TO PERMIT AXIAL MOVEMENT THEREOF TOWARDS AND AWAY FROM THE FIXED STEM ELECTRODE, MEANS FOR ACCURATELY SETTING AND MEASURING THE POSITION OF THE SECOND ELECTRODE RELATIVE TO THE FIXED STEM ELECTRODE, AN ELECTRICALLY CONDUCTIVE DIAPHRAGM INTERCONNECTING THE SECOND ELECTRODE AND CASING IN AN AIRTIGHT MANNER, SAID DIAPHRAGM CONSTITUTING A SHORT-CIRCUIT ELEMENT DETERMINING THE EFFECTIVE END OF THE FURTHER COAXIAL-LINE PORTION AND FORMING WITH THE CASING A SUBSTANTIALLY AIRTIGHT CHAMBER ENCLOSING THE MUTUALLY OPPOSED PLANE END FACES OF THE TWO ELECTRODES, SAID CHAMBER HAVING A SEALABLE ACCESS OPENING ADJACENT TO THE SAID END FACES FOR THE INSERTION AND REMOVAL OF SPECIMEN DISCS, MEANS FOR EVACUATING SAID AIRTIGHT CHAMBER, AND ELECTRICAL MEANS FOR HEATING AT LEAST ONE OF SAID STEM ELECTRODES CLOSELY ADJACENT TO SUCH END FACE THEREOF, A FURTHER SHORT-CIRCUIT ELEMENT ELECTRICALLY INTERCONNECTING THE CASING AND FIXED STEM ELECTRODE AND MOVABLE AXIALLY OF THE LATTER TO VARY THE COMPOUND EFFECTIVE LENGTH OF THE COAXIAL-LINE PORTIONS, AN INPUT ELEMENT AND AN OUTPUT ELEMENT FOR ELECTRICAL OSCILLATIONS, EACH EXTENDING INTO THE AIRTIGHT CHAMBER, MEANS FOR CONDUCTING COOLING FLUID THROUGH THE INTERIOR OF THE FIXED STEM ELECTRODE TO A POINT A PREDETERMINED DISTANCE FROM THE PLANE END THEREOF, COOLING MEANS FOR COOLING THE WALL OF THE CASING, AT LEAST IN THE VICINITY OF THE PLANE ENDS OF THE ELECTRODES, COOLING MEANS FOR THE STEM OF THE MOVABLE ELECTRODE, MEANS FOR ASCERTAINING THE TEMPERATURE AT A POINT NEAR THE END FACE OF AT LEAST ONE OF THE STEM ELECTRODES, AND MEANS OPERABLE FROM OUTSIDE THE AIRTIGHT CHAMBER TO ADJUST THE POSITION OF THE MOVABLE SHORT-CIRCUIT MEMBER.