Dishwasher Drying Time Control Using Evaporation Temperature Profiles
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Solution Overview
Problem
Conventional dishwashers with inherent heat drying methods run a fixed drying cycle regardless of load, leading to inefficient energy use and inadequate moisture sensing due to saturated air conditions, which does not account for varying loads and environmental factors.
Innovation Solution
A method that regulates drying time by recording and analyzing a temperature profile between items to be washed and a condensation surface, detecting the degree of evaporation to determine complete drying, allowing for automatic detection and optimization of the drying process without complex sensors, using a simple temperature sensor and software evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed drying cycle is used regardless of load, then adequate drying result is achieved for large load, but energy consumption increases for small load
Solution Approach 1:
The drying cycle duration is made dynamic rather than fixed. The control unit adjusts the drying time based on the actual load size detected by the sensor, extending the cycle for large loads and shortening it for small loads, thereby optimizing energy consumption while maintaining adequate drying results for all load conditions
Solution Approach 2:
A sensor detects the actual load size and provides feedback to the control unit, which then adjusts the drying cycle parameters accordingly. This closed-loop control enables the system to adapt the drying process to the specific load conditions, preventing energy waste on small loads while ensuring sufficient drying time for large loads
2Reliability
If a fixed drying cycle is used regardless of load, then adequate drying result is achieved for large load, but drying time increases for small load
Solution Approach 1:
The drying cycle duration is dynamically adjusted based on load size. For small loads, the cycle is shortened to reduce time loss, while for large loads, the cycle is extended to ensure adequate drying. This dynamic timing resolves the contradiction between maintaining reliable drying results and minimizing time loss
Solution Approach 2:
The sensor-based feedback system provides real-time information about load size, enabling the control unit to optimize the drying cycle duration. This feedback mechanism ensures that the drying process is neither too long (wasting time) nor too short (compromising results) for any given load condition
3Measurement precision
If moisture sensors are used in inherent heat drying, then moisture detection is attempted, but sensors fail due to saturated air conditions
Solution Approach 1:
Instead of directly measuring moisture in the saturated air (which causes sensor failure), the system uses an indirect approach by detecting load size with a sensor and using this information to control the drying process. The load sensor acts as an intermediary that provides useful information without being affected by the saturated air conditions
Solution Approach 2:
The patent replaces the problematic moisture sensing system with a load detection system. Instead of using sensors that must directly measure moisture in the saturated environment (mechanical/electrical sensing in harsh conditions), the system substitutes this with a load detection approach that controls drying based on load size, avoiding the saturated air environment entirely
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
Enables energy savings by adjusting drying time based on load, ensuring adequate drying results while reducing energy consumption, and eliminating the need for complex sensors, as the method is independent of chamber insulation and environmental conditions.
Implementation Method 1
the items to be washed are heated to a predetermined initial temperature (T 0)
Implementation Method 2
detecting a characteristic for the degree of evaporation of water from the surface of the items to be washed
Implementation Method 3
A cold surface increases drying performance. The moisture from the indoor air can condense on it
Data Source
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AI summary
Process for controlling the drying time in a dish washer with a rinsing chamber for reception of the material to be dried, where this material is heated to a predetermined starting temperature which is higher than the condensation surface which communicates with the rinsing chamber. The method involves the steps:(a) determination of the temperature course of a characteristic temperature T during drying of the material and (b) detection of a characteristic feature of the extent of water evaporation from the surface of the material on the basis of the temperature course of the characteristic temperature. An independent claim is included for a dish washer with a rinsing chamber for the material to be dried.