Filter Element Venting to Prevent Liquid Droplet Redispersion

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Solution Overview

Problem

Existing pneumatic filters allow aggregated liquid droplets to redisperse into compressed air due to the uncontrolled flow of compressed air, especially at the inlet where air pressure is high, leading to inefficiencies in removing contaminants.

Innovation Solution

A filter element design with a non-perforated portion on the outer core at the upper part of the central channel to control the flow direction of compressed air, combined with a downflow channel to prevent liquid droplets from redispersing, using a specific ratio of non-perforated area to channel length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vent holes are formed uniformly over the entire surface of the outer core, then compressed air can flow efficiently through the filter body, but aggregated liquid droplets redisperse into the compressed air flow

Engineering Contradiction:
Improveair flow efficiencyVSAvoidcontaminant removal effectiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The outer core is designed with non-uniform vent hole distribution: the lower portion has vent holes to facilitate air flow and liquid drainage, while the upper portion is non-perforated to prevent liquid droplet redispersion. This local differentiation allows each region to perform its specific function optimally without interfering with the other.

Inventive Principle:
Principle #3Local quality

2Speed

If compressed air flows horizontally through the filter body, then the shortest path is taken through the filter elements, but liquid droplets move laterally with the air flow and disperse again

Engineering Contradiction:
Improveair flow speedVSAvoidliquid separation effectiveness
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The filter body is segmented into functionally distinct zones: the lower portion with vent holes handles air intake and liquid drainage, while the upper non-perforated portion handles liquid droplet containment. This segmentation allows the air flow path and liquid separation path to be independently optimized.

Inventive Principle:
Principle #1Segmentation

3Stress or pressure

If the entire outer core surface is perforated, then air pressure is evenly distributed, but liquid droplets are carried by high-pressure air flow and redisperse at the inlet

Engineering Contradiction:
Improveair pressure distributionVSAvoidcontaminant removal effectiveness
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The outer core implements local quality differentiation with perforated lower portion for pressure distribution and drainage, and non-perforated upper portion for liquid droplet containment. This allows pressure management and liquid separation to occur in separate zones with appropriate characteristics.

Inventive Principle:
Principle #3Local quality

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

Effectively prevents the redispersion of aggregated liquid droplets by controlling air flow, ensuring high removal efficiency of contaminants from compressed air.

Implementation Method 1

the liquid is gradually aggregated into large droplets, and the liquid droplets move down by their own weight and drip into the filter case 41

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

the compressed air introduced into the central space 48 flows out so as to horizontally transverse the vent holes 49a of the inner core 49, the inner filter member 50, the vent holes 51a of the outer core 51, and the outer filter member 52

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3943178B1Filter element
Publication Date: 2025.09.03 SMC CORP
  • EP3943178B1 patent drawingFigure 1
  • EP3943178B1 patent drawingFigure 2
  • EP3943178B1 patent drawingFigure 3

AI summary

[Object] To prevent aggregated liquid droplets from dispersing again into compressed air by controlling the flow of the compressed air flowing through a filter element. [Solution] A filter element 1 has a central channel 10, an inner core 6, an inner filter member 7, an outer core 8, and an outer filter member 9. The inner core 6 has vent holes 25 formed around a portion facing the central channel 10. The outer core 8 has a perforated portion 8b having vent holes 26 formed therearound and a non-perforated portion 8a having no vent hole. The region over which the non-perforated portion 8a is formed along the central channel 10 extends from a position above the central position C of the central channel 10 in the up-down direction to the upper end of the central channel 10. The region over which the perforated portion 8b is formed along the central channel 10 extends from the lower end of the non-perforated portion 8a to the lower end of the central channel 10.