Filter Assembly Radial Drain and Circumferential Alignment

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Solution Overview

Problem

Existing filter systems have a protruding drain configuration that increases the axial length and footprint, making them unsuitable for space-constrained applications, and lack structures for circumferential alignment of the filter cartridge, increasing the risk of misplacing or losing the drain plug during maintenance.

Innovation Solution

A filter assembly with a substantially cylindrical center tube and a plate connected to it, featuring an orifice and cap with pilot features that allow for circumferential alignment and a fluid-tight seal with a stand pipe and flange, minimizing the axial length and footprint while ensuring proper installation and preventing drain plug misplacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protruding drain configuration is used, then the drain can effectively remove fluid from the canister, but the axial length and footprint of the filter system increase

Engineering Contradiction:
Improvedrain functionVSAvoidaxial length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent relocates the drain plug from an axial protrusion to a radial position within the filter element structure. The drain passage extends radially outward from the central axis rather than axially, allowing the drain plug to be positioned at the periphery. This dimensional change reduces the axial length while maintaining the drain's fluid removal capability through the side wall of the canister.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the drain plug is completely removed from the drain passage, then fluid can be drained from the filter housing, but the plug is likely to be misplaced or lost during maintenance

Engineering Contradiction:
Improvedrain functionVSAvoidmaintenance procedure
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The drain plug is nested within a recess in the filter element structure rather than being a separate removable component. The recess provides a storage cavity that holds the drain plug when not in use, allowing it to be easily accessed and reinstalled without risk of loss. The plug remains integrated with the filter element assembly, eliminating the risk of misplacement while maintaining drain functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If no circumferential alignment structures are provided, then the filter cartridge can be installed freely, but the filter element cannot be properly aligned with the longitudinal axis

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidcircumferential alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent incorporates asymmetric keyway structures on both the filter element and the support structure. A keyway extends radially outward from the central axis at a specific angular position, creating an asymmetric geometry that allows only one correct rotational orientation during installation. This asymmetric feature provides precise circumferential alignment while maintaining ease of installation through a simple snap-fit mechanism.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP2976144B1Filter assembly
Publication Date: 2019.12.04 CATERPILLAR INC
  • EP2976144B1 patent drawingFigure 1
  • EP2976144B1 patent drawingFigure 2
  • EP2976144B1 patent drawingFigure 3

AI summary

A filter element (14) includes a substantially cylindrical center tube (56) having a first end (57), a second end (59) opposite the first end, and a central longitudinal axis. The filter element also includes filter media (16) extending circumferentially around and longitudinally along the center tube, and a plate (58) connected to the center tube proximate the first end. The plate includes an orifice (70) and a cap (63). The orifice includes a pilot feature (72) configured to locate the filter element at a single circumferential position relative to the longitudinal axis, the cap extending from a top surface (60) of the plate toward the second end and having an inner wall (32) configured to mate with a drain plug (30). The orifice and the cap ma y be disposed radially inward of an inner circumference of the center tube, and at least one of the orifice and the cap extends circumferentially around an additional longitudinal axis spaced radially from the central longitudinal axis of the center tube.