Cap Filter With Spring-Operated Bypass Valve

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Solution Overview

Problem

Existing filtration systems for lubrication oils face issues where the main filter clogs, leading to either unfiltered liquid passing through or increased pressure loss and potential clogging of the reserve filter, depending on the design of the bypass valve mechanism.

Innovation Solution

A filter design featuring a coaxial main and reserve filtering element with a spring-operated closure means that opens the bypass valve when pressure difference exceeds a threshold, allowing liquid to flow through the reserve filter, reducing pressure loss and preventing unfiltered liquid from passing, while maintaining filtration efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bypass valve is designed to allow liquid flow through the reserve filter when the main filter clogs, then continuous operation is maintained, but unfiltered liquid may pass through if the main filter material breaks up

Engineering Contradiction:
Improvecontinuous operationVSAvoidunfiltered liquid passage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The reserve filter is nested inside the main filter housing, with the bypass valve positioned to direct flow through the reserve filter only when the main filter is clogged. This nested arrangement allows the reserve filter to serve as a backup without occupying external space, maintaining compact design while ensuring continuous filtration capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The bypass valve acts as an intermediary mechanism that controls flow direction between the main filter and reserve filter. It responds to pressure differential changes to activate flow through the reserve filter only when needed, preventing unfiltered liquid from bypassing the filtration system under normal conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If the bypass valve opens when pressure difference increases, then pressure loss is reduced, but the reserve filter may clog more quickly by unfiltered liquid

Engineering Contradiction:
Improvepressure lossVSAvoidreserve filter lifespan
Core Design Contradiction:
Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The bypass valve incorporates a pressure differential sensing mechanism that provides feedback control. When the pressure difference across the main filter exceeds a threshold indicating clogging, the valve automatically opens to redirect flow through the reserve filter, reducing pressure loss. The valve closes when pressure differential normalizes, preventing the reserve filter from processing unfiltered liquid during normal operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the flow path parameter based on pressure differential conditions. Under normal pressure conditions, flow passes through the main filter. When pressure differential increases beyond a threshold, the parameter changes and flow is redirected through the reserve filter via the bypass valve, optimizing both pressure loss reduction and filter lifespan.

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If a spring-operated closure means is used for the bypass valve, then automatic opening at threshold pressure is achieved, but the valve dynamics and opening pressure control require precise design

Engineering Contradiction:
Improveautomatic valve openingVSAvoidvalve mechanism design
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The bypass valve is designed as a self-actuating mechanism using a spring-loaded closure means that automatically responds to pressure differential changes. The spring force is calibrated to overcome the closure force only when pressure difference exceeds the threshold, enabling automatic opening without external control systems. The valve self-regulates flow based on operating conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring-operated closure means applies localized force at the valve seating area to control opening and closing. The spring stiffness and preload are specifically designed to provide the required opening pressure threshold, creating a simple yet effective control mechanism that balances automation with design simplicity.

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

The solution ensures continuous operation by switching to the reserve filter when the main filter clogs, minimizing pressure loss and preventing unfiltered liquid from entering the reserve filter, thus maintaining effective filtration and extending its lifespan.

Implementation Method 1

when the pressure difference across the main filter exceeds a given value, the spring gives in for opening the closure means

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

The closure means is spring-operated

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

a main filtering element and a reserve filtering element

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP2488272B1Cap filter and use
Publication Date: 2021.05.26 PARKER HANNIFIN MANUFACTURING FINLAND OY
  • EP2488272B1 patent drawingFigure 1~4

AI summary

The invention relates to a filter, which has a body (1) provided with a coaxially cylindrical main filtering element (17) supplied with liquid from an inlet channel, and a cylindrical reserve filtering element (19.1; 19.2) whose filtering resistance is not more than equal to that of the main filtering element, a closure means (10), which has a closed position blocking the flow of liquid past the main filtering element, and an open position allowing liquid to flow through the main filtering element, and a closure means spring (11), which urges the closure means to the closed position and which gives way when the pressure difference across the main filtering element exceeds a given value. The body (1) includes a removable, body- closing cap (3) which, when in attachment, presses the closure means against the spring. The invention can be used for example for the filtration of lubrication oils.