Kitchen Scale Strain Gauge Coating for Moisture Protection
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Solution Overview
Problem
Conventional kitchen scales are not liquid-tight, leading to moisture and dirt ingress, which damages load cells and affects measurement accuracy, especially during cleaning or exposure to high humidity, making them unreliable for household use.
Innovation Solution
A liquid-tight and vapor-permeable coating is applied to the load cells' strain gauges, with a sensor system to monitor moisture levels, switching the scales to an inactive state when wet and back to active when dry, ensuring accurate weighing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the kitchen scales are designed as open scales with a gap between the support plate and substructure for easy cleaning, then ease of operation is improved, but moisture and dirt can penetrate inside damaging the load cells and affecting measurement precision
Solution Approach 1:
A liquid-tight and vapor-permeable coating is applied to the load cell to protect the strain gauge from moisture and chemical influences during cleaning, while allowing water vapor to pass through for drying. This thin film protection resolves the contradiction by enabling both easy cleaning access and measurement precision protection.
Solution Approach 2:
A sensor system monitors the moisture content of the coating in real-time and provides feedback to the control unit. When moisture exceeds a threshold, the system switches to an inactive state preventing incorrect measurements. This feedback mechanism ensures measurement precision is maintained by detecting and responding to moisture conditions that could affect accuracy.
2Measurement precision
If a completely closed housing is implemented to protect against moisture, then measurement precision is improved, but the load cells cannot deflect properly due to restricted movement, reducing reliability
Solution Approach 1:
The liquid-tight and vapor-permeable coating forms a flexible protective layer on the load cell that does not restrict the mechanical deflection required for measurement. Unlike rigid enclosures, this thin film allows the load cell to move freely while still providing moisture protection, thus maintaining both measurement precision and reliability.
Solution Approach 2:
The coating's selective permeability parameters are optimized to allow water vapor transmission while blocking liquid water and chemical substances. This parameter change enables the load cell to maintain its mechanical properties and deflection capability while being protected from harmful moisture effects.
3Reliability
If a watertight polymer coating is applied to the load cell for protection, then reliability is improved, but the coating complexity and cost increase significantly
Solution Approach 1:
A single liquid-tight and vapor-permeable coating is applied directly to the load cell surface, providing comprehensive protection against water and chemical influences without requiring complex multi-layer structures or additional protective components. This simple yet effective coating reduces device complexity while maintaining high reliability.
Solution Approach 2:
The coating performs multiple functions simultaneously: it provides liquid-tight protection against water ingress, vapor-permeability for drying, and chemical resistance against cleaning agents. This multi-functionality in a single layer reduces overall system complexity compared to multiple separate protective measures.
4Measurement precision
If the kitchen scales remain in an inactive state until completely dry to ensure measurement accuracy, then measurement precision is improved, but the loss of time for drying increases productivity loss
Solution Approach 1:
The sensor system continuously monitors moisture content and provides real-time feedback to the control unit. When the moisture level drops below the predetermined threshold indicating sufficient dryness for accurate measurement, the system automatically switches from inactive to operational state. This feedback-based decision-making optimizes the balance between measurement precision and productivity by ending the drying wait time as soon as accuracy requirements are met.
Solution Approach 2:
The predetermined threshold value for moisture content is optimized to represent the minimum required dryness level for accurate measurement. By setting this parameter appropriately, the system ensures measurement precision is maintained while minimizing the drying time required before the scales can be used again.
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 solution allows kitchen scales to be used under water or in a dishwasher while maintaining measurement accuracy by preventing incorrect readings during moisture exposure and ensuring quick recovery after drying.
Implementation Method 1
load cells which are interposed between the flow of forces from the base plate to the base and have at least one strain gauge which is deformed by the deformation of the load cell as a result of a load lying on the base plate
Implementation Method 2
the load cell is provided with a liquid-tight and vapor-permeable coating at least in the area of the strain gauges
Implementation Method 3
the electronics having a sensor system for measuring the moisture content of the coating
Data Source
Figure 1~3
AI summary
The invention relates to a kitchen scale comprising a base plate (1), a support structure (2) for the base plate, load cells (6) with at least one strain gauge (10), electronics (4) capable of calculating the weight of the load, a display device for showing the measured weight, and a battery compartment for a power source supplying the electronics (4). The kitchen scale is designed as an open kitchen scale with a water-permeable gap between the base plate (1) and the support structure (2). The electronics (4), the display device, and the battery compartment are enclosed in a moisture-proof manner. Known scales have the disadvantage that the load cells (6) are not protected against the ingress of liquid.This improves the invention in that the load cell (6) is provided, at least in the area of the strain gauges (10), with a liquid-tight and vapor-permeable coating (9) and no further covering layer in the area of the coating (9).