Wireless Capacitive Sensor for Carding Gap Measurement
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Solution Overview
Problem
Existing methods for measuring the carding gap on spinning preparation machines are hindered by fiber material interference with laser sensors during production, and inductive/capacitive sensors fail to accurately record critical deflections of flat bars, especially under real production conditions with varying temperature settings.
Innovation Solution
Integration of sensors within the flat bars with wireless signal transmission allows for contactless carding gap measurement during production, enabling continuous monitoring without fiber material influence and maintaining safety devices' operation, even with closed doors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser sensor is used to measure the carding gap, then the measurement can be performed through the carding gap, but the laser beam is interrupted by fiber material during production making the receiver unable to receive signals
Solution Approach 1:
The patent replaces the optical laser measurement system with a capacitive sensor system that uses electrical fields instead of light beams. The capacitive sensors (e.g., inductive sensors or capacitive distance sensors) can measure the carding gap through electrical field interaction without being blocked by fiber material, thus resolving the contradiction between measurement capability and signal interruption during production.
2Measurement precision
If inductive or capacitive distance sensors are used outside the clothing areas, then the distance between flat bar guide and cylinder can be determined, but the critical deflection of flat bars in the middle of the machines is not recorded
Solution Approach 1:
The patent divides the measurement system into multiple segments by placing capacitive sensors at different locations: outside the clothing areas for overall distance measurement and integrated sensors within the flat bars for detecting local deflections. This segmentation allows comprehensive monitoring of both the general carding gap and specific flat bar deflections throughout the machine.
Solution Approach 2:
The patent integrates measurement electronics and capacitive sensors directly within the flat bar structure itself, nesting the sensing system inside the mechanical component. This allows the flat bars to serve dual functions: their mechanical role in the carding process and their role as integrated sensor carriers for detecting deflections and positions.
3Reliability
If the card remains closed for safety during production, then safety devices remain in operation, but contactless measurement during production with fiber material throughput is prevented
Solution Approach 1:
The patent replaces the laser-based optical measurement system with capacitive sensors that use electrical fields, which are not interrupted by fiber material. This substitution enables continuous contactless measurement during production when the card is closed and fiber material is being processed, maintaining both safety and measurement capability simultaneously.
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 accurate, continuous carding gap measurement during production with fiber material throughput, maintaining safety and operational integrity by using wireless transmission and embedded measuring electronics within the flat bars, effectively accounting for temperature variations.
Implementation Method 1
distance sensors (inductive or capacitive sensors) determine the existing distance between the flat bar guide and the cylinder
Implementation Method 2
distance sensors (inductive or capacitive sensors) determine the existing distance between the flat bar guide and the cylinder
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
In a device on a spinning preparation machine, e.g. carding machine, with a traveling cover with a plurality of garnished cover bars for measuring distances between the cover bars and the garnished drum, in which at least one sensor (18a, 18b, 18c) is provided with which the tip distance (carding distance) between the garnished surfaces can be detected, the sensor is assigned to a cover bar and is arranged opposite the drum garnishing (4a).In order to enable non-contact carding gap measurement under production conditions and wireless transmission of the measurement data to an evaluation unit, the sensor is located directly opposite the drum assembly, the cover bar with the at least one sensor for distance measurement is electrically connected to another cover bar (17), it has measuring electronic components (and a power source) and the measurement data can be transmitted wirelessly (online) to an electronic evaluation unit (20).