Zeolite Drying Temperature Sensing for Dishwasher Drying Control
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Solution Overview
Problem
Dishwashing machines with drying units face challenges in precise control of the drying process due to varying loads and temperature fluctuations, requiring expensive temperature sensors to detect high temperatures near the absorption column.
Innovation Solution
Placing a temperature sensor upstream of the drying unit and downstream of the washing compartment in the air circulation loop allows for the use of simpler, cost-effective sensors to detect significant temperature changes, enabling precise control of the drying process without the need for absolute temperature detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature detection is performed downstream of the absorption column or in the water-absorbing material itself, then the drying control precision is improved, but the cost of temperature sensors increases due to high temperature requirements
Solution Approach 1:
The patent introduces an intermediary location (upstream of the absorption column) where temperature detection can be performed indirectly. The temperature sensor detects air temperature before it enters the high-temperature zone, using the air as a mediator to convey drying progress information without requiring the sensor to withstand extreme temperatures.
Solution Approach 2:
The patent creates a temperature copy or proxy measurement by detecting temperature at a different location (upstream of absorption column) rather than directly in the high-temperature zone. This indirect temperature measurement serves as a sufficient substitute for direct measurement, enabling cost-effective sensor selection.
2Reliability
If temperature sensors are placed downstream of the absorption column to detect high temperatures, then accurate drying monitoring is achieved, but the device complexity and sensor requirements increase
Solution Approach 1:
The patent inverts the conventional approach by placing the temperature sensor upstream of the absorption column rather than downstream or within it. This reversal allows the use of standard low-cost sensors instead of specialized high-temperature sensors, simplifying the overall device design while maintaining monitoring effectiveness.
3Measurement precision
If absolute temperature detection is performed in the high-temperature zone, then precise drying endpoint determination is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the measurement parameter from absolute temperature to temperature change (ΔT). By monitoring the temperature difference or change in the air circulation loop rather than absolute high temperature values, the system achieves sufficient precision for drying endpoint detection while enabling the use of inexpensive standard temperature sensors.
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
This approach simplifies the control of the drying process, reduces manufacturing costs, and provides additional user options for different drying results by analyzing temperature profiles for fault detection and varying drying conditions.
Implementation Method 1
They make use of the characteristic of the zeolite whereby heat is emitted upon the absorption of water as a consequence of the absorption reaction.
Implementation Method 2
heat is emitted upon the absorption of water as a consequence of the absorption reaction
Implementation Method 3
a temperature sensor is arranged upstream of the drying unit and downstream of the washing compartment in the direction of flow of the air circulating in the air circulation loop
Implementation Method 4
They can have a fan for maintaining the airflow from the washing compartment into the absorption column and back
Data Source
AI summary
A dishwashing machine is provided having a washing compartment, a drying unit that includes an absorption column with a reversibly dehydratable drying agent, and having an air circulation loop through the washing compartment and the drying unit. A temperature sensor is arranged in front of the drying unit and to the rear of the washing compartment with respect to the direction of the flow of air circulating in the air circulation loop.