| 摘要 |
PCT No. PCT/NL92/00181 Sec. 371 Date Jun. 13, 1994 Sec. 102(e) Date Jun. 13, 1994 PCT Filed Oct. 9, 1992 PCT Pub. No. WO93/07504 PCT Pub. Date Apr. 15, 1993.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.
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