Structural unit, in particular heating pump, comprising a heatable tube section for a water-conducting domestic appliance, and water-conducting domestic appliance comprising such a structural unit
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Solution Overview
Problem
Liquid heating devices in water-bearing household appliances, such as dishwashers and washing machines, face issues with deposit formation due to incorrect water hardness settings, detergent usage, and salt replenishment, leading to operational failures and customer service calls, and existing solutions like surface structuring for lime deposit areas add processing complexity and may shorten the device's lifespan.
Innovation Solution
A heating pump with a pipe section featuring mechanical structures that create locally different flow speeds and two temperature measuring devices arranged outside the pipe section, ensuring they remain dry and functional, allowing for accurate detection of temperature differences that indicate lime scale formation, enabling early detection and prevention of deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface structuring is used to create lime deposit areas, then lime deposit detection is enabled, but manufacturing complexity increases and device lifespan may be reduced
Solution Approach 1:
The invention extracts the temperature measurement function from the interior of the pipe section and places temperature sensors on the exterior surface. This allows lime deposit detection without requiring surface structuring of the pipe interior, thereby reducing manufacturing complexity while maintaining measurement capability.
Solution Approach 2:
The pipe section wall acts as an intermediary that transmits thermal information from the interior liquid flow conditions to the exterior temperature sensors. By measuring temperature differences on the exterior surface, the system indirectly detects lime deposit formation without direct contact with the liquid or modification of the pipe interior.
2Measurement precision
If temperature measuring devices are placed inside the pipe section, then direct temperature measurement is possible, but the devices are exposed to liquid and may fail
Solution Approach 1:
The temperature measuring devices are extracted from the liquid-exposed interior environment and relocated to the dry exterior surface of the pipe section. This maintains their ability to measure temperature through thermal conduction while protecting them from liquid exposure and potential failure.
Solution Approach 2:
The pipe section wall serves as a thermal intermediary that conducts temperature information from the liquid-contact side to the sensor side. This allows accurate temperature measurement without the sensors being directly exposed to the liquid, thereby ensuring long-term reliability.
3Productivity
If uniform flow velocity is maintained throughout the pipe section, then liquid heating is efficient, but temperature difference measurement for deposit detection becomes difficult
Solution Approach 1:
The invention creates local variations in flow velocity by positioning temperature sensors at locations with naturally different flow characteristics (one in a low-velocity recirculation zone, another in a higher-velocity flow zone). This allows temperature difference measurement for deposit detection without requiring non-uniform flow throughout the entire pipe section, thus maintaining heating efficiency while enabling measurement.
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 solution allows for reliable and robust detection of lime scale deposits, enabling timely countermeasures and reducing the risk of device damage, while maintaining long-term functionality of temperature sensors and reducing maintenance costs.
Implementation Method 1
the pipe section can be heated from the outside via heating conductors arranged on the outside of the pipe section
Implementation Method 2
the pipe wall is heated from the outside by the heater and cooled on the inside by the liquid flowing there
Implementation Method 3
At the respective measuring point, there is preferably a mixed temperature from the heating temperature prevailing at the measuring point and the temperature that the liquid has when it arrives at the inside of the pipe section opposite the measuring point
Data Source
AI summary
The invention relates to a structural unit (14), in particular a heating pump for a water-conducting domestic appliance (1), in particular a domestic dishwasher, having a heatable tube section (15) through which a liquid can flow during operation and in which one or more mechanical structures (19; 20) are arranged that produce locally different flow speeds of the liquid. The exterior (24) of the tube section (18) is paired with at least two temperature measuring devices (22; 23). A first temperature measuring device (22) is arranged radially outside of a region with a lower flow speed or worse inflow, and a second temperature measuring device (23) is arranged radially outside of a region with a higher flow speed or better inflow.