Method for managing a microwave heating device and microwave heating device

Patent metadata

Field	Value
Publication number	US-11032878-B2
Application number	US-201715713861-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Sep 26, 2016
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A method for managing a microwave heating device able to operate based on a first signal having a first fundamental harmonic frequency that is within the microwave range, wherein operation of the microwave heating device (1) is interrupted or modified when, inside the microwave heating device (1), the presence of a second signal is detected, the latter having harmonic components which have frequencies that are different from a fundamental harmonic frequency and an intensity higher than a critical reference value.

First claim

The invention claimed is:

1. A method for managing a microwave heating device wherein the microwave heating device comprises:
a heating chamber;
a signal generator, the signal generator being of the solid-state type and being able to generate sinusoidal signals with a fundamental harmonic frequency within the microwave range;
one or more radiating portions positioned in the heating chamber and supplied by the signal generator via a supply circuit, for radiating microwaves in the heating chamber;
the signal generator and the supply circuit being settable according to multiple operating configurations, each operating configuration having its own fundamental harmonic frequency; the method comprising:
a setting step in which the signal generator and the supply circuit are set according to a first operating configuration having a first fundamental harmonic frequency; and
a supply step in which the signal generator generates a first signal with the first fundamental harmonic frequency, which is transmitted by means of the supply circuit, and, according to the first operating configuration, to the one or more radiating portions according to a forward direction of propagation that goes from the signal generator to the one or more radiating portions;

and wherein, during the supply step, the method also comprises:
a step of monitoring a second signal that propagates in the supply circuit according to a reflected direction of propagation that goes from the one or more radiating portions to the signal generator, and/or that is generated in the heating chamber;
a step of detecting the intensity of one or more harmonic components of said second signal, which have a frequency higher than the fundamental harmonic frequency;
a step of comparing the intensity detected with a critical reference value;
and, when the comparison step indicates that the intensity detected is higher than the critical reference value, a safety intervention step in which the supply step is interrupted or in which the operating configuration is changed.

2. The method according to claim 1 , wherein the supply circuit comprises a plurality of independent branches, each of which comprises a power amplifier connected to one or more radiating portions, wherein according to the method the monitoring and detecting steps are performed at each branch with reference to the intensity of only the second signal affecting the branch.

3. The method according to claim 1 , wherein the critical reference value is equal to 5-10 times the intensity of a third signal that propagates in the supply circuit according to the reflected direction of propagation and/or that is generated in the heating chamber in a reference operating condition.

4. The method according to claim 1 , wherein the monitoring step and/or the detecting step are carried out with reference to a signal proportional to the second signal or to one or more harmonic components of the second signal.

5. The method according to claim 1 , wherein alternatively:
the detecting step comprises detection of the intensity of only a second harmonic component;
the detecting step comprises detection of the overall intensity of a group of harmonic components having a frequency higher than the fundamental harmonic frequency; or
the detecting step comprises detection of the overall intensity of all of the harmonic components having a frequency higher than the fundamental harmonic frequency.

Assignees

• Illinois Tool Works

Inventors

• Carcano Marco
• Sclocchi Michele

Classifications

• H05B6/702

  using coaxial cables · CPC title

• H05B6/666

  Safety circuits (emergency protective circuits in general H02H) · CPC title

• H05B6/686 Primary

  Circuits comprising a signal generator and power amplifier, e.g. using solid state oscillators · CPC title

• H05B6/705

  using microwave tuning · CPC title

• H05B6/72

  Radiators or antennas · CPC title