Sealing Roller with Protrusions for Blister Pack Pressure Control

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Solution Overview

Problem

Existing sealing devices for blister packs face challenges in maintaining consistent pressure across the sealing line, leading to potential punctures in the cover film due to high pressure in areas with blister cups and inadequate sealing in areas without blister cups, while also being costly and complex to produce.

Innovation Solution

A sealing device with a sealing roller and counter-roller that features a displaceable design with elevations on the lateral surface, allowing for adjustable distance between the rollers to vary pressure based on the presence of blister cups, ensuring consistent sealing without punctures and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pressure along the sealing line is increased to ensure complete sealing, then sealing reliability is improved, but punctures occur in the cover film in areas with blister cups

Engineering Contradiction:
Improvesealing reliabilityVSAvoidpuncture damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The counter roller is designed with varying contact surface areas in different longitudinal sections. The contact surface area is largest in sections where the film surface is most reduced by recesses for blister cups, and smallest in sections where the film surface is not interrupted. This creates locally adapted pressure distribution, ensuring sufficient sealing pressure where needed while preventing excessive pressure that would cause punctures.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameter of the counter roller surface (contact area) to dynamically adjust pressure distribution. By varying the contact surface area along the longitudinal section, the system adapts the sealing pressure parameter to match the local film conditions, resolving the contradiction between sufficient sealing and puncture prevention.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the pressure exerted by the rollers is reduced to prevent punctures, then film damage is avoided, but the pressure in areas with longer effective sealing lines becomes insufficient for complete sealing

Engineering Contradiction:
Improvefilm damageVSAvoidsealing completeness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Different longitudinal sections of the counter roller are designed with different contact surface areas tailored to the local film conditions. Sections with blister cup recesses have larger contact areas to reduce pressure and prevent punctures, while sections with uninterrupted film surfaces have smaller contact areas to maintain sufficient sealing pressure for complete sealing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The contact surface area parameter of the counter roller is varied along its longitudinal section to create corresponding pressure variations. This parameter change ensures that pressure is locally optimized for each section's specific film conditions, preventing both punctures and incomplete sealing.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the contact pressure is made variable to adapt to different film positions, then sealing quality is improved, but the device complexity and manufacturing costs increase significantly

Engineering Contradiction:
Improvesealing qualityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using expensive actuators and complex control systems to dynamically adjust roller pressure, the invention employs a simple, cost-effective counter roller with pre-formed varying contact surface areas. This static geometric solution replaces complex active control systems, significantly reducing device complexity and manufacturing costs while maintaining high sealing quality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the geometric parameter (contact surface area) of the counter roller during manufacturing to create a passive, built-in pressure distribution system. This eliminates the need for complex active parameter adjustment mechanisms during operation, resolving the contradiction between sealing quality and device complexity.

Inventive Principle:
Principle #35Parameter changes

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 device achieves reliable and error-free sealing of the cover film to the shaped film by dynamically adjusting pressure, preventing punctures and ensuring complete sealing across the entire sealing line, even at high conveying speeds, while being simpler and less costly to produce.

Implementation Method 1

The sealing roller and counter roller exert pressure on the forming film and the top film, thereby sealing the films together

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

Both the essentially cylindrical sealing roller and the essentially cylindrical counter roller are in essentially linear contact with the film adjacent to them

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The sealing roller is heated, and the sealing roller and counter roller exert pressure on the forming film and the top film, thereby sealing the films together

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3882008B1Sealing device and method
Publication Date: 2022.05.18 UHLMANN PAC SYST
  • EP3882008B1 patent drawingFigure 1a~1b
  • EP3882008B1 patent drawingFigure 2~3

AI summary

A sealing device (2) according to the invention comprises a sealing roller (10) and a counter roller (12) which are arranged parallel to each other, so that a gap (24) is formed between the sealing roller (10) and the counter roller (12), wherein at least one of the sealing roller (10) and counter roller (12) is displaceably mounted in a radial direction relative to the other of the sealing roller (10) and counter roller (12), so that their distance (D) is variable; and wherein at least one sealing roller (10) and counter roller (12) has a plurality of circumferentially spaced-apart protrusions (26) on its cylindrical surface (16, 20) such that the distance (D) corresponds to a first distance (D1) if no protrusion (26) is arranged in the area of ​​the gap (24), and to a second distance (D2) which is greater than the first distance (D1) if a protrusion (26) is arranged in the area of ​​the gap (24).