Annular Pre-Motor Filter Design for Compact Hand Vacuum Cleaners
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Solution Overview
Problem
Conventional surface cleaning apparatuses with cylindrical filters require larger housings due to their tall design, limiting their compactness and efficiency in providing upstream surface area.
Innovation Solution
An annular pre-motor filter with a hollow interior and non-circular cross-sectional area is used in a hand vacuum cleaner, offering a squatter shape with enhanced upstream surface area, allowing for improved filter life and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a cylindrical filter is used, then the filter provides a larger upstream surface area, but the filter requires a taller housing which increases the overall size of the apparatus
Solution Approach 1:
The filter transitions from a cylindrical shape to an annular shape with a hollow interior. This dimensional change allows air to flow through both the outer cylindrical surface and the inner hollow cavity, effectively doubling the upstream surface area without increasing the external footprint or housing length in the flow direction.
Solution Approach 2:
The hollow interior of the annular filter creates a nested structure where air flow paths are concentric. The inner hollow cavity is nested within the outer filter structure, allowing dual flow paths (outer and inner surfaces) to coexist within the same external dimensions, maximizing surface area utilization.
2Area of stationary object
If a cylindrical filter with larger upstream surface area is used, then filter performance is improved, but the apparatus becomes less compact
Solution Approach 1:
By transforming the filter from a solid cylinder to an annular structure with hollow interior, the design utilizes the internal volume for additional filtration surface area. This allows the apparatus to maintain a compact external volume while providing increased upstream surface area through the dual-flow-path annular configuration.
3Area of stationary object
If the filter is made taller to increase upstream surface area, then filtration capacity is improved, but the apparatus complexity and housing requirements increase
Solution Approach 1:
The annular filter segments the air flow into two distinct paths: outer flow through the cylindrical surface and inner flow through the hollow cavity. This segmentation allows both flow paths to occur simultaneously within the same filter component and housing space, increasing surface area without requiring additional housing sections or complex multi-stage arrangements.
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 annular filter design provides increased upstream surface area while maintaining or enhancing filter life, enabling a more compact and efficient surface cleaning apparatus with reduced housing size requirements.
Implementation Method 1
a pre-motor filter positioned in a pre-motor filter housing downstream from the air treatment member
Data Source
AI summary
A hand vacuum cleaner having a front end and a rear end positioned in a rearward direction rearward of the front end is described herein. The hand vacuum cleaner includes a dirty fluid inlet, an air treatment member downstream of the dirty fluid inlet, a pre-motor filter positioned in a pre-motor filter housing downstream from the air treatment member, a suction motor downstream of the pre-motor filter, an air flow path extending from the pre-motor filter to the suction motor, a clean air outlet downstream of the suction motor, and a handle. The pre-motor filter has a longitudinal length in the rearward direction that is longer than a transverse length in a direction transverse to the rearward direction. The pre-motor filter housing has first and second rearwardly extending pre-motor filter housing sidewalls and the pre-motor filter has first and second rearwardly extending pre-motor filter sidewalls that are positioned transversely inwardly of the pre-motor filter housing sidewalls. The pre-motor filter sidewalls are an upstream face of the pre-motor filter and the pre-motor filter has an inner cavity that is downstream of the upstream face.