(under subclass 200) Subject matter which includes means to create a magnetic field in which is placed a heated ferromagnetic material, the apparatus to sense and indicate being responsive to the magnetic field modified by the heated material to determine whether the heated material is at least at or below the critical temperature at which the heated material loses its ferromagnetism.
(1) Note. The apparatus to sense and indicate the magnetic field may be a magnet which functions to pass its magnetic flux through the material to induce magnetism in the material if its temperature is below the Curie point of the material to attract the material to the magnet.
SEE OR SEARCH THIS CLASS, SUBCLASS:
224, for the temperature control of the test material or an element of the test circuit.
228, for permanent magnets which locate ferromagnetic material by inducing magnetism in the material and noting the relative movement of the permanent magnet to material to be located.
SEE OR SEARCH CLASS
148, Metal Treatment, particularly
195+, for flame cutting or burning combined with sensing, subclasses 215+ for processes of carburizing or nitriding of metal combined with sensing or testing, subclass 240 for testing combined with reactive coating of metal, or subclasses 508+ for processes of measuring, testing, or sensing combined with treatment of solid or semi-solid metal to modify or maintain the internal physical structure (i.e., microstructure) or chemical property of metal. If casting, fusion bonding, machining, or working is combined with the treatment of solid or semi-solid metal to modify or maintain the internal physical structure (i.e., microstructure), there is a requirement that there be significant heat treatment as defined in section III, A, of the Class 148 definition.
335, Electricity: Magnetically Operated Switches, Magnets, and Electromagnets,
209+, for magnets and electromagnets.
340, Communications: Electrical,
597, for a ferromagnetic temperature sensor in a signalling system; and subclasses 577 and 600 for ferromagnetic flame and radiation sensors, respectively, in a signalling system.
356, Optics: Measuring and Testing,
43+, for optical pyrometers.
361, Electricity: Electrical Systems and Devices,
158, for temperature indicating instruments with systems for magnetizing, demagnetizing, or controlling a magnetic field.
374, Thermal Measuring and Testing,
176, for a thermometer having a ferromagnetic sensor.
