Core temperature sensor and combination cooking appliance with core temperature sensor
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Solution Overview
Problem
Core temperature probes in microwave ovens can act as antennas, leading to overheating and distorted temperature measurements due to unwanted electrical currents when used in microwave cooking modes.
Innovation Solution
A core temperature sensor design with a contact tube and microwave trap that positions the handle end at a local minimum of the electromagnetic field, reducing current flow and heat input, and includes a contact point with the cable shield to manage electrical currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the core temperature probe is used in microwave mode, then temperature monitoring is achieved, but the measuring probe acts as an antenna receiving microwaves causing unwanted electrical currents and overheating
Solution Approach 1:
The patent positions the handle-side end of the contact tube at a distance corresponding to an electrical length of at most one-quarter wavelength of the microwave radiation. This placement converts the harmful microwave energy into a beneficial positioning effect, where the end of the contact tube sits at a minimum of the electromagnetic field (E-field), thereby reducing current flow and energy input while maintaining temperature monitoring capability
Solution Approach 2:
The patent changes the positional parameter of the contact tube relative to the microwave field by setting its distance from the contact point to correspond to an electrical length of at most one-quarter wavelength. This parameter change transforms the probe's interaction with microwave radiation from harmful (acting as an antenna) to beneficial (positioned at field minimum), resolving the contradiction between measurement capability and harmful heating effects
2Measurement precision
If the core temperature probe is inserted into the food, then core temperature measurement is enabled, but local heating of the food occurs in the area of the probe
Solution Approach 1:
The patent applies the same quarter-wavelength positioning principle to the contact tube's handle-side end, positioning it at a minimum of the electromagnetic field. This converts the potentially harmful microwave interaction into a beneficial arrangement that minimizes energy absorption, thereby preventing local heating of the food while maintaining the probe's temperature measurement function
3Ease of operation
If the core temperature probe is in standby position not inserted into food, then it is ready for use, but the probe heats up excessively and may be damaged
Solution Approach 1:
The patent performs a preliminary protective action by pre-positioning the handle-side end of the contact tube at a distance corresponding to an electrical length of at most one-quarter wavelength during manufacturing. This preliminary positioning ensures that when the probe is in standby mode, the end is already at a minimum of the electromagnetic field, preventing excessive heating and damage before the probe is even inserted into food
Solution Approach 2:
The patent changes the fixed positional parameter of the contact tube during design and manufacturing, setting it at the optimal quarter-wavelength distance. This parameter change ensures that regardless of whether the probe is in standby or inserted, the handle-side end remains at a minimum of the electromagnetic field, preventing overheating and extending the probe's service life
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents damage to the core temperature probe and ensures accurate temperature readings, extending the probe's lifespan and improving cooking precision in microwave combination ovens.
Implementation Method 1
the handle-side end of the contact tube is located at a minimum of the electromagnetic field generated by the microwave radiation
Implementation Method 2
The contact point is at a distance from the handle-side end that corresponds to an electrical length of the microwave radiation in the handle section, which is shorter than or equal to a quarter of the wavelength of the microwave radiation used in the combination cooking appliance
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a core temperature probe (28) for a combination oven (10), comprising a measuring section (32) and a handle section (30). A contact tube (50) is also provided, in which a cable (36) is guided. The cable (36) has an exposed section (88) in the handle section (30) in which the contact tube (50) forms a contact point (90) with the cable (36). The contact point (90) is located at a distance d1 from the handle end (52), which corresponds to an electrical wavelength of the microwave radiation in the handle section (30) that is less than or equal to one-quarter of the wavelength of the microwave radiation used in the combination oven (10). The invention further relates to a combination oven (10) with the core temperature probe (28).