Abstract: A method of controlling an inductive heating circuit, having a varying load, to seal a packaging material is provided. The method comprises generating AC power of at least two frequencies on at least one inductor in the inductive heating circuit; determining of the resulting phase shift in the inductive heating circuit from the current generated at the at least two frequencies; determining the impedance of the inductive heating circuit for each of the at least two frequencies; determining a load characteristics of the inductive heating circuit based on the relationship between the determined impedance and the determined phase shift; determining an impedance operating range; and selecting an AC output frequency for an induction power generator based on the load characteristics which results in the least amount of phase shift from a set ideal value and which is associated with an impedance that is within the impedance operating range.

Abstract: A method of controlling an inductive heating circuit, having a varying load, to seal a packaging material is provided. The method comprises generating AC power of at least two frequencies on at least one inductor in the inductive heating circuit; determining the resulting phase shift in the inductive heating circuit from the current generated at the at least two frequencies; determining the impedance of the inductive heating circuit for each of the at least two frequencies; determining a load characteristics of the inductive heating circuit based on the relationship between the determined impedance and the determined phase shift; determining an impedance operating range; and selecting an AC output frequency for an induction power generator based on the load characteristics which results in the least amount of phase shift from a set ideal value and which is associated with an impedance that is within the impedance operating range.

Abstract: Packaging Machine operable to produce sealed packages made of heat-seal sheet packaging material and containing a food product, and comprising an ultrasonic sealing device including an electrical power signal source operable to generate an electrical power signal; an ultrasonic transducer electrically coupled to the electrical power signal source to receive the electrical power signal and responsively heat seal the sheet packaging material; and an electronic counter operable to count the ultrasonic sealing cycles of the ultrasonic sealing device.

Abstract: Packaging Machine operable to produce sealed packages made of heat-seal sheet packaging material and containing a food product, and comprising an ultrasonic sealing device including an electrical power signal source operable to generate an electrical power signal; an ultrasonic transducer electrically coupled to the electrical power signal source to receive the electrical power signal and responsively heat seal the sheet packaging material; and an electronic counter operable to count the ultrasonic sealing cycles of the ultrasonic sealing device.