Capacitive RF Inspection of Tobacco Filter Capsules
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Solution Overview
Problem
Current methods in the tobacco processing industry fail to reliably check the quality of rod-shaped articles, particularly filter cigarettes, after complete processing, as they do not effectively detect changes in density or liquid filling of capsules, especially after multiple processing steps that can damage capsules, leading to potential leakage and quality issues.
Innovation Solution
A capacitive HF measuring device is designed to have articles dip transversely axially into a measuring capacitor with a homogeneous HF field, allowing precise detection of density changes and liquid filling, using a trough conveyor device with insulated capacitor electrodes and a zero detector control circuit to maintain virtual ground, reducing noise and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microwave sensors are used to inspect capsules during production, then detection of capsule fill level and position is achieved, but detection reliability deteriorates after storage time due to capsule leakage and drying
Solution Approach 1:
The patent performs capsule inspection at two distinct time points: first during production before storage, and second after storage before packaging. This preliminary action during production establishes a baseline measurement, and the second inspection after storage detects any changes that occurred during storage, thereby maintaining detection reliability throughout the storage period
Solution Approach 2:
The system uses microwave sensors to continuously monitor capsule properties and provides feedback to the control system. The control system processes this feedback information to identify capsules that have leaked or dried during storage, enabling real-time quality control and maintaining detection reliability after storage
2Productivity
If multiple processing steps are performed on filter rods, then complete product manufacturing is achieved, but capsule damage and leakage increase
Solution Approach 1:
The patent performs inspection at multiple stages: after capsule insertion during production, after storage, and before packaging. This preliminary action at each stage detects capsule damage early, allowing for timely intervention before subsequent processing steps cause further damage or allow damaged products to progress
Solution Approach 2:
The microwave sensing system continuously monitors capsule integrity throughout the multiple processing steps and provides feedback to the control system. This enables real-time detection of capsule damage and leakage, allowing the system to identify and isolate affected capsules before they progress to packaging, thereby maintaining capsule integrity despite multiple processing steps
3Reliability
If conventional inspection methods are used after processing, then quality control is attempted, but detection precision deteriorates due to position-dependent measurement variations
Solution Approach 1:
The patent transitions from conventional single-point measurement to a distributed array of microwave sensors that measure across multiple positions and dimensions. This dimensional expansion allows the system to capture position-independent characteristics of capsule fill level and detect anomalies regardless of their location in the filter rod
Solution Approach 2:
The microwave sensing system is designed to perform multiple measurement functions simultaneously: detecting capsule fill level, position, integrity, and changes during storage. This multi-functionality enables comprehensive quality control with a single inspection system, achieving position-independent detection across all capsule properties
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 enables precise and position-independent detection of changes in filter density and liquid filling, enhancing measurement reliability and ensuring quality control of filters and capsules after complete processing, thereby preventing damaged or improperly filled items from progressing to packaging.
Implementation Method 1
a capacitive RF measuring device (30) for the capacitive determination of at least one property of an endless strand of material
Implementation Method 2
a high-frequency field emanating from them penetrates each cigarette end
Implementation Method 3
whose surface area is smaller than the surface area of the conductive electrode surface on the first side of the transmission channel. Thus, the capacitor surfaces are configured as two surfaces or sides of the transmission channel, one side being supplied with an RF signal of typically approximately 1 MHz to 100 MHz, and the other being held to ground
Implementation Method 4
The difference between the virtual mass of the capacitor electrode and the ground potential of the base body is typically less than 1 mV to about 1 mV. This ensures a very homogeneous field geometry
Data Source
Figure 1
Figure 2~3
Figure 4(a)~4(c)
AI summary
The invention relates to an arrangement for inspecting transversely conveyed rod-shaped articles (14) of the tobacco processing industry, in particular for inspecting liquid-filled capsules (18) in filters (16) of filter cigarettes (14), comprising at least one trough conveyor device (10, 20) with troughs (12, 22) for receiving and transversely conveying rod-shaped articles (14) and at least one capacitive RF measuring device (30) with at least one measuring capacitor (34, 34'). The invention further relates to a machine of the tobacco processing industry and a method for inspecting transversely conveyed rod-shaped articles (14) of the tobacco processing industry, in particular for inspecting liquid-filled capsules (18) in filters (16) of filter cigarettes (14).In the arrangement according to the invention, the at least one capacitive RF measuring device (30) has at least one longitudinally extended, one-sided or two-sided open lateral passage channel (40) along a conveying path of the rod-shaped articles (14) for a section (15) of the articles (14) projecting beyond the respective recesses (12, 22), wherein the at least one passage channel (40) laterally penetrates the at least one measuring capacitor (34, 34'), so that projecting sections (15) of the rod-shaped articles (14) pass through an RF measuring field in the at least one measuring capacitor (34) on their conveying path through the passage channel (40).