Vacuum Cleaner Filter Bag Double-Seal Structure for Leak Prevention

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Solution Overview

Problem

Existing filter bags for vacuum cleaners face challenges in achieving reliable sealability with the connection piece on the vacuum cleaner side, leading to potential leaks and inefficiencies in air filtration.

Innovation Solution

The filter bag features a plastic injection-molded retaining plate with two seals made of TPE, designed to widen radially, providing a one-piece injection-molded connection that enhances sealing by creating a pressure lock between different pressure areas, ensuring that even if one seal is damaged, air does not leak from the dirty side to the clean side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single seal is used on the retaining plate, then the structure is simple, but the sealing reliability is insufficient and leaks may occur

Engineering Contradiction:
Improvesealing reliabilityVSAvoidseal structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing system is divided into two separate seals (first seal and second seal) positioned at different locations on the retaining plate. The first seal seals between the retaining plate and connection piece, while the second seal seals between the retaining plate and partition wall. This segmentation ensures that if one seal fails, the other continues to provide sealing, thus improving reliability without requiring a single complex seal design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual seal arrangement acts as a backup system where the second seal provides redundant sealing capability. If the first seal deteriorates or fails during operation, the second seal maintains the pressure differential and prevents gas leakage. This beforehand cushioning approach ensures continuous sealing reliability throughout the service life of the filter bag.

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

2Reliability

If seals are made separate from the retaining plate, then manufacturing is simpler, but the sealing connection reliability decreases

Engineering Contradiction:
Improveseal connection reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The seals are integrated into the retaining plate as a single injection-molded component. The retaining plate is made of thermoplastic material, and the seals are formed directly from the same material in one manufacturing process. This merging eliminates separate assembly steps, ensures consistent material properties, and creates strong mechanical bonds between the seals and the retaining plate, thereby improving connection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The retaining plate and seals are constructed from thermoplastic materials that can be injection-molded in one piece. The use of thermoplastic polymers allows for complex geometries including integrated seals with radial widening features. The material properties provide both structural integrity and sealing capability, combining multiple functions in a single composite component.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the seal does not widen radially, then the structure is simpler, but the sealing effect is insufficient under pressure differential

Engineering Contradiction:
Improvesealing effectVSAvoidseal geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The seals are designed with radial widening that allows them to dynamically respond to pressure differentials. Under operating conditions, the pressure difference between the inside and outside of the filter bag causes the radially widening seals to expand and press against the mating surfaces (connection piece and partition wall). This dynamic sealing action ensures maintained sealing effectiveness throughout the pressure cycle without requiring overly complex seal geometries.

Inventive Principle:
Principle #15Dynamics

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 design significantly improves the sealing effect, preventing raw gas from reaching the clean gas side, even if one of the seals is compromised, by utilizing the pressure differences across the seals to maintain a tight seal and ensuring that clean air escapes if a seal fails, thus maintaining filtration efficiency.

Implementation Method 1

The pressure area of higher pressure always forces the seal into the sealing contact position. The pressure area of higher pressure always forces the seal into the sealing contact position.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP2364631B1Vacuum cleaner with an attached filter bag and filter bag
Publication Date: 2012.11.28 VORWERK & CO INTERHOLDING GMBH
  • EP2364631B1 patent drawingFigure 1
  • EP2364631B1 patent drawingFigure 2~3
  • EP2364631B1 patent drawingFigure 4~5

AI summary

The vacuum cleaner contains a filter bag (4) having a holding plate (9) with an inflow aperture (10) with a connector (13) bounding a first pressure regions (P1). There is a first seal (17) between the holding plate and this connector. The holding plate is also sealed by a second seal (18) from a second pressure region (P2) formed by a partition wall (15) fixed to the housing.