초록 ▼

A high frequency magnetic field exposure meter for use in an induction heat sealing operation for heat sealing metal foil elements in closures to containers to be closed by the closures. The meter has a magnetic field sensing coil, a rectifier to convert the a.c. output from the coil to a d.c. outpu

A high frequency magnetic field exposure meter for use in an induction heat sealing operation for heat sealing metal foil elements in closures to containers to be closed by the closures. The meter has a magnetic field sensing coil, a rectifier to convert the a.c. output from the coil to a d.c. output, an integrating circuit to integrate the d.c. output over an exposure period to an h.f. magnetic field, and a display device to indicate the integrated exposure value generated by the integrating circuit. During operation, the meter generates a quantitative reading indicating exposure to the h.f. magnetic flux as an integral of the magnetic flux, which generates the induction heating currents, over the exposure period during the induction heat sealing operation, and the reading provides a useful measure of the induction heating generated in an induction heat sealable closure.

대표청구항 ▼

A high frequency magnetic field exposure meter suitable for use in an induction heat sealing process for heat sealing the metal foil wad elements in a closure to a container to be closed by said closure, during which operation each closure passes beneath an induction coil of an induction heat sealin

A high frequency magnetic field exposure meter suitable for use in an induction heat sealing process for heat sealing the metal foil wad elements in a closure to a container to be closed by said closure, during which operation each closure passes beneath an induction coil of an induction heat sealing apparatus, said meter comprising: a magnetic field sensing coil designed to be exposed to the same h.f. magnetic flux as said metal foil wad elements of said closures receive during the induction heat sealing operation; a rectifier to convert the a.c. output from said coil to a d.c. output; an integrating circuit to accumulate said d.c. output over an exposure period equal to the exposure period in which the metal foil is sealed to the container during normal operation of the apparatus; a display device to indicate the accumulated value generated by said integrating circuit.