Segmented Weld Seam Structure for Burst-Resistant Filter Bags

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Solution Overview

Problem

Vacuum cleaner filter bags experience weakness at weld seams, leading to bursting or material tear when filled with dirt, especially with nonwovens above 200 g/m² or when connecting multiple layers, resulting in uncontrollable dirt leakage.

Innovation Solution

A vacuum cleaner filter bag with a weld seam featuring alternating welded and unwelded areas, where the welded areas are 1.0 mm to 10.0 mm long and 1.3 mm to 10.0 mm wide, and the unwelded areas are greater than 1.0 mm to 5.0 mm long, providing enhanced tear strength without compromising sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous linear weld seams are used to connect filter material layers, then sealing effectiveness is improved, but the weld seam becomes a permanent weak point that bursts or tears under mechanical stress

Engineering Contradiction:
Improvesealing effectivenessVSAvoidweld seam strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The continuous weld seam is divided into alternating welded and unwelded areas along its linear course. The welded areas (1.0-10.0 mm long) provide sealing, while the unwelded areas (>1.0-5.0 mm long) maintain the inherent strength of the filter material layers, preventing the weld seam from becoming a continuous weak point that bursts under stress.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the weld seam have different properties: welded areas provide sealing functionality while unwelded areas maintain material strength. This local differentiation allows the weld seam to simultaneously achieve both sealing effectiveness and mechanical strength, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #3Local quality

2Strength

If ultrasonic welding is applied to nonwoven materials with mass per unit area above 200 g/m², then connection strength is improved, but the weld seam becomes prone to bursting when the filter bag is filled with dirt

Engineering Contradiction:
Improveconnection strengthVSAvoidresistance to bursting
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By segmenting the weld seam into alternating welded and unwelded areas, the structure maintains strong connections where needed (welded areas for sealing) while preserving the material's inherent resistance to bursting in the unwelded areas, preventing catastrophic failure when the filter bag is filled with dirt.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The unwelded areas act as pre-positioned stress relief zones that prevent the propagation of tears and bursts throughout the entire weld seam. When mechanical stress occurs during filling, these unwelded areas absorb and distribute the stress, preventing the weld seam from bursting.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 significantly increases the tear strength of the weld seam, preventing the filter bag from bursting under mechanical stress while maintaining effective sealing, even with high dirt loads and multi-layer nonwoven materials.

Implementation Method 1

at least one linear weld seam, by means of which the interior of the vacuum cleaner filter bag is closed off from the surroundings at least on one side. The weld seam connects at least two layers of the filter material to one another

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Implementation Method 2

a vacuum cleaner filter bag made of a thermally weldable filter material

Methodology Applied
Scientific EffectThermal welding: Heating

Data Source

PatentEP2944247B1Vacuum cleaner filter bag with high strength weld seam, method for its production and tool and ultrasound welding installation for producing an extremely strong weld seam
Publication Date: 2016.09.21 EUROLIFTERS HLDG NV
  • EP2944247B1 patent drawingFigure 1
  • EP2944247B1 patent drawingFigure 2~3
  • EP2944247B1 patent drawingFigure 4

AI summary

The present invention relates to a vacuum cleaner filter bag (10) made of a thermally weldable filter material, which forms the enclosed interior of the vacuum cleaner filter bag. The interior is closed at least on one side by means of a weld seam (S) designed according to the invention, in which at least two layers (R, V) of the filter material are welded together. The weld seam (S) designed according to the present invention is characterized by a significantly higher tensile strength compared to weld seams known from the prior art. The invention also relates to a method for manufacturing the vacuum cleaner filter bag (10), a tool for producing the high-strength weld seam (S), and an ultrasonic welding system in which this tool is integrated.