Microwave Drying of Extruded Honeycomb Bodies
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Solution Overview
Problem
Microwave-assisted drying of honeycomb bodies can lead to fractures due to unfavourable irradiation, which affects the mechanical stability and usability of ceramic honeycomb catalysts used for exhaust gas purification.
Innovation Solution
A system and method for drying honeycomb bodies using a microwave oven with microwave radiators oriented at a predefined angle relative to the channel walls, avoiding parallel irradiation and ensuring anti-parallel irradiation to absorb stresses and prevent fractures, combined with a control unit for maintaining the correct orientation and adjusting microwave power to manage pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microwave radiators are arranged to irradiate honeycomb bodies with a directional microwave beam at different angle directions, then drying efficiency is improved, but fractures may arise within the honeycomb body during the drying process
Solution Approach 1:
The patent applies local quality by orienting microwave radiators at specific angles (30-60 degrees) relative to the channel walls, creating localized irradiation patterns that optimize drying in specific regions while avoiding parallel irradiation that causes fractures. The control unit adjusts microwave power distribution to different zones of the honeycomb body based on their orientation relative to the radiators.
Solution Approach 2:
The patent implements dynamics through the control unit that actively adjusts microwave power output based on real-time detection of honeycomb body orientation and position. The system dynamically modulates irradiation intensity to accommodate variations in channel wall orientation, preventing fractures while maintaining drying efficiency.
2Productivity
If conventional IR irradiation is used to assist drying, then drying speed is increased, but a temperature gradient is produced (hot on the outside and cold on the inside) which is disadvantageous
Solution Approach 1:
The patent changes the fundamental parameter of irradiation from conventional IR to microwave radiation, which penetrates the material and heats it uniformly from the inside out. The control unit further modulates microwave power to compensate for variations in material thickness and moisture content, achieving uniform temperature distribution throughout the honeycomb body.
3Use of energy by moving object
If parallel irradiation is used relative to channel walls, then microwave energy is efficiently coupled, but stresses cannot be absorbed and fractures occur
Solution Approach 1:
The patent applies asymmetry by deliberately avoiding symmetric parallel irradiation and instead using asymmetric angle orientations (30-60 degrees) relative to the channel walls. This asymmetric irradiation approach creates stress distribution patterns that the honeycomb structure can better absorb, preventing fracture while maintaining adequate energy coupling.
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
The approach significantly reduces the occurrence of fractures during the drying process, ensuring uniform and efficient drying while maintaining the mechanical stability of the honeycomb catalysts, thereby enhancing their usability in applications like exhaust gas purification.
Implementation Method 1
a plurality of microwave radiators (6) which are offset with respect to one another in the longitudinal direction (L) of the microwave oven (4)... irradiating the honeycomb body (14) with a directional microwave beam
Implementation Method 2
The honeycomb bodies are typically composed of a ceramic mass, and the drying of the honeycomb bodies is a partial step during the manufacture of a ceramic honeycomb body
Implementation Method 3
the drying is carried out by sublimation from a frozen state, i.e. that the water passes directly into the gas phase
Data Source
Figure 1~2
AI summary
A system (2) for extruding and drying an extruded honeycomb body (14) which has channels (18) that extend in a longitudinal direction (L) and which channels (18) are each bounded by first channel walls (20a) that extend in a first direction (A) which is transverse relative to the longitudinal direction (L), and by second channel walls (20b) that extend in a second direction (B) which is also transverse relative to the longitudinal direction (L) comprises: (i) an extruder (16) having an extrusion head (17) for producing the honeycomb body (14) by extrusion; (ii) a microwave oven (4) comprising an arrangement of a plurality of microwave radiators (6), each microwave radiator being for irradiating the honeycomb body with a directional microwave beam in an irradiation direction (S); and (iii) a feed unit (12) adjoining the extruder (16) for transferring the honeycomb body from the extruder (16) into the microwave oven (4), wherein either: (a) the extrusion head (17) of the extruder is oriented in such a way that during operation of the system the orientation position of the extruded honeycomb body (14) resulting from the extrusion when transferred into the microwave oven (4) is such that the irradiation direction (S) of each microwave radiator (6) is oriented at a predefined irradiation angle (a) which is not zero relative to each of the two transverse directions (A, B) of the first and second channel walls (20a, 20b); GBor (b) the system (2) is designed to sense the orientation of the first and/or second channel walls (20a, 20b) of the honeycomb body produced by the extruder and to move the honeycomb body and/or a microwave radiator (6) into a set point orientation such that the irradiation direction (S) of each microwave radiator (6) is oriented at a predefined irradiation angle (a) which is not zero relative to each of the two transverse directions (A, B) of the first and second channel walls (20a, 20b).