Patent ID: 9681496
Date: 2017-06-13
CPC Classifications: F27B,F27D,G01K,H05B

Claim:
1. A high temperature calibration furnace comprising: a core having an elongated central test cavity for testing/calibration of a temperature-sensitive component, the core having at least three electrical heating elements adjacent to the test cavity for heating of the test cavity by a supply of electrical power to the heating elements, the heating elements including a first end heating element adjacent to a first end portion of the test cavity, a second end heating element adjacent to a second end portion of the test cavity opposite the first end portion thereof, and a central heating element between the first and second end heating elements; and control circuitry for managing the supply of electrical power from a power supply to the first end heating element, the second end heating element, and the central heating element, the control circuitry having operating means for periodically configuring interconnections of the first end heating element, the second end heating element, and the central heating element during multiple phases of a duty cycle, including a first phase in which the power supply is electrically connected to the central heating element such that electrical current passes only through the central heating element, a second phase in which the power supply is electrically connected to the first and second end heating elements in series, and a third phase in which the power supply is electrically connected to one of the first and second end heating elements and the central heating element in series such that electrical current passes only through one of the first and second heating elements and the central heating element in series without passing through the other of the first and second end heating elements.