Filter Bag Restraint in Wet Vacuum Suction for Stable Liquid Flow

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Solution Overview

Problem

Existing suction devices face inefficiencies in generating negative pressure and risk liquid particles scattering, leading to reduced performance due to the filter bag inflating and potentially blocking the liquid flow, which can result in undersupply of fluid to power tools.

Innovation Solution

A suction device design that includes a filter bag retaining part which separates the container interior into a filter bag receiving space and a liquid delivery space, preventing the filter bag from expanding into the liquid conveying chamber, ensuring reliable operation and effective filtration without the need for a cartridge filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the filter bag is allowed to expand freely in the container interior, then the filtration surface area increases, but the filter bag blocks the liquid flow path and enters the suction unit, reducing suction performance

Engineering Contradiction:
Improvefiltration surface areaVSAvoidsuction performance
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The container interior is segmented into two distinct spaces by the filter bag retaining part: a filter bag receiving space where the filter bag can expand, and a liquid delivery space where liquid flows to the pump. This segmentation prevents the filter bag from blocking the liquid flow path while maintaining adequate filtration surface area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter bag retaining part acts as an intermediary structure between the filter bag and the liquid delivery system. It provides support for the filter bag, defines its expansion boundaries, and prevents it from entering the liquid delivery space or suction unit, thus mediating between the need for filtration surface area and the need to maintain suction performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a cartridge filter is added on the inlet side of the suction unit, then liquid particles are prevented from entering the suction unit, but the device complexity increases

Engineering Contradiction:
Improveprotection against liquid particle scatteringVSAvoidnumber of filter components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter bag retaining part combines multiple functions: it supports the filter bag, defines the boundary between filter bag receiving space and liquid delivery space, and prevents both filter bag expansion into the liquid flow path and liquid particle scattering into the suction unit. This merging of functions eliminates the need for a separate cartridge filter.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter bag retaining part is a multi-functional component that simultaneously achieves filtration support, spatial separation, and protection against liquid particle scattering. This universal component replaces what would otherwise require multiple separate components including a cartridge filter.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enhances the filter effect, prevents liquid from entering the suction unit, and maintains reliable liquid pumping, even under high dirt loads, while allowing the filter bag to expand without blocking the liquid outlet, ensuring efficient cleaning and preventing tool undersupply.

Implementation Method 1

a mixture of a carrier liquid and entrained dirt particles being able to be sucked in via a suction inlet by means of negative pressure generated by the suction unit

Methodology Applied
Scientific EffectNegative pressure generation: Pressure Gradient

Implementation Method 2

the dirt particles are retained by the filter element, and wherein the carrier liquid filtered by the filter element

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3148390B1Suction apparatus for cleaning purposes
Publication Date: 2018.08.15 HILTI AG
  • EP3148390B1 patent drawingFigure 1
  • EP3148390B1 patent drawingFigure 2
  • EP3148390B1 patent drawingFigure 3

AI summary

The invention relates to a suction apparatus 10 for cleaning purposes, comprising a container 20 having a container interior 22, also comprising a suction subassembly 58, further comprising a changeable-shape filter element 46, which can be arranged in the container interior 22, and additionally comprising a pumping subassembly 60, wherein a mixture made up of a carrier fluid and entrained particles of dirt can be taken in via a suction inlet by means of negative pressure generated by the suction subassembly 58, and the particles of dirt are restrained by the filter element 46, and wherein the carrier fluid filtered by the filter element 46 can be delivered, by the pumping subassembly 60, from the container interior 22 to a fluid outlet 36. In order to provide such a suction apparatus 10 which can be made to operate more reliably, the invention proposes that the filter element 46 should be a filter bag 48, through which the mixture is taken in by the suction subassembly 58, and that the suction apparatus 10 should comprise a filter-bag-restraining part 66, which subdivides the container interior 22 into a filter-bag-accommodating space 70 and a fluid-delivery space 72, wherein the filter bag 48 is arranged in the filter-bag-accommodating space 70 and is prevented, by the filter-element-restraining part 66, from expanding into the fluid-delivery space 72, from which carrier fluid flowing around, or through, the filter-element-restraining part 66 is delivered by the pumping subassembly 60.