Aseptic Load Cell with Curved Dome Cover
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Solution Overview
Problem
Existing load cells used in aseptic environments, such as food processing, face challenges in cleanliness due to horizontal surfaces and depressions that trap dirt, bacteria, and fungi, making them difficult to clean and unsuitable for hygiene regulations.
Innovation Solution
A hermetically sealed load cell design featuring a longitudinal body with a double bending beam, strain gages, and a flexurally stiff pipe sleeve enclosed by ring elements with flexible membranes, ensuring all force is directed through the strainable measuring parts and preventing contamination accumulation, allowing for easy cleaning and disinfection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hermetically sealed load cell with pot-shaped metallic sheet metal parts is used, then measurement precision is improved, but ease of operation deteriorates due to difficult cleaning in depressions
Solution Approach 1:
The patent replaces the pot-shaped depression with a dome-shaped cover element that has a curved, convex surface. This curvature eliminates the horizontal surfaces and recesses where contaminants accumulate, making the load cell easy to clean while maintaining the hermetic seal. The dome shape allows cleaning agents to flow over the surface without pooling, directly resolving the cleaning difficulty while preserving measurement accuracy.
Solution Approach 2:
The patent extracts the strain gage mounting function from the pot-shaped depression and relocates it to the curved surface of the dome-shaped cover. The strain gages are applied directly on the curved outer surface of the cover element, eliminating the need for the problematic pot-shaped recess while maintaining the hermetic enclosure and measurement capability.
2Manufacturing precision
If horizontal surfaces and depressions are provided on load cell, then manufacturing precision is improved, but object-affected harmful factors worsen due to bacterial and fungal accumulation
Solution Approach 1:
The dome-shaped cover element with its convex curved surface eliminates horizontal surfaces and depressions that serve as breeding grounds for bacteria and fungi. The curved geometry prevents contaminant accumulation and facilitates complete cleaning, directly addressing the hygiene requirements while maintaining manufacturing precision through controlled forming processes.
3Measurement precision
If strain gage strips are applied on the surface of bending rod, then measurement precision is improved, but ease of operation deteriorates as cleaning with watery agents becomes impossible
Solution Approach 1:
The patent uses a thin-walled, flexurally soft dome-shaped cover element that provides hermetic enclosure while allowing the strain gages to be applied on its outer curved surface. The thin-walled structure transmits force effectively to the strain gages for accurate measurement, while the smooth curved surface enables easy cleaning with watery agents, resolving the contradiction between measurement precision and cleanability.
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 design achieves high measurement accuracy, prevents bacterial and fungal growth, and allows for secure installation in aseptic areas, ensuring the load cell's longevity and usability in harsh environments.
Implementation Method 1
strain gage strips are applied on both sides as shear force pick-ups or transducers, which produce a proportional electrical signal in connection with a weight loading
Implementation Method 2
the force measuring element consists of a vertical bending spring
Implementation Method 3
pot-shaped metallic sheet metal parts are welded into the bored holes, and hermetically tightly enclose the sensitive electrical measuring elements
Data Source
AI summary
A load cell includes a longitudinal body including force input and output elements and a bending beam, strain gages, and a hermetically sealed enclosure. A force applied onto the input element perpendicularly to the longitudinal axis causes bending strain of the beam, which is measured by the strain gages. The enclosure includes a stiff pipe sleeve and two ring elements, which each include a membrane that is more flexible than the pipe sleeve, and which support the pipe sleeve relative to and spaced radially away from the longitudinal body. The membranes preferably decouple the pipe sleeve from the longitudinal body so that essentially none of the applied force is shunted into the pipe sleeve. Preferably a cylindrical outer surface of the pipe sleeve can avoid accumulation of contaminants.