Suction Return Filter Dual-Function Valve Design

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Solution Overview

Problem

Existing suction return filters face inefficiencies in filtration, particularly during after-suction operations, and have complex designs that are difficult to produce and assemble, leading to increased pressure differences and reduced hydraulic system efficiency.

Innovation Solution

A suction return filter design featuring a freely movable anti-cavitation valve seat interacting with a spring-loaded preload valve, where the anti-cavitation valve fully accommodates the preload valve, allowing for a unified structural unit that simplifies production and assembly, ensuring efficient fluid flow and filtration by allowing fluid to enter only when spring force is exceeded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a protective screen with small dimensions is used in the anti-cavitation valve, then the valve can be compact, but the pressure difference before and after the screen increases considerably, leading to deterioration in hydraulic system efficiency

Engineering Contradiction:
Improvevalve compactnessVSAvoidhydraulic system efficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The preload valve is nested within the anti-cavitation valve structure. The preload valve piston is formed as an extension of the anti-cavitation valve piston, and the preload valve is integrated into the bottom plate of the filter housing. This nested arrangement allows both valves to occupy the same spatial envelope, maintaining compactness while providing separate flow paths that reduce pressure differential across the screen.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If separate preload valve and anti-cavitation valve arrangements are used, then each valve can be optimized independently, but the device complexity and assembly difficulty increase significantly

Engineering Contradiction:
Improvevalve optimizationVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The preload valve and anti-cavitation valve are merged into a single integrated assembly. The preload valve piston forms part of the anti-cavitation valve piston structure, and both valves share common mounting features and flow paths. This merging maintains the functional independence and optimization capabilities of separate valves while dramatically reducing assembly steps and overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the anti-cavitation valve and preload valve are directly connected to the tank, then the structure is simplified, but filtration during after-suction operation is not optimally ensured

Engineering Contradiction:
Improvestructural simplicityVSAvoidfiltration quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The screen is positioned upstream of the integrated valve assembly, performing preliminary filtration of the hydraulic fluid before it reaches the valve mechanisms. This preliminary action ensures that particles are removed before the fluid enters the valve system, maintaining filtration quality during after-suction operation while keeping the overall structure simple through the integrated valve design.

Inventive Principle:
Principle #10Preliminary action

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 design enhances the functional integration of preload and anti-suction valves, simplifies manufacturing and assembly, and maintains efficient filtration during both suction and return operations without significant pressure loss, ensuring reliable operation and improved hydraulic system performance.

Implementation Method 1

a spring-loaded second seat valve (preload valve) is axially integrated, which allows fluid to flow exclusively from the suction-return filter when the spring force is exceeded

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a suction return filter is known from the prior art that is prepared for installation in a pressure medium tank... in order to clean the circulating equipment (e.g. hydraulic fluid) of impurities

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP2493589B1Suction/return filter having a dual-function valve
Publication Date: 2014.10.15 ROBERT BOSCH GMBH
  • EP2493589B1 patent drawingFigure 1
  • EP2493589B1 patent drawingFigure 2
  • EP2493589B1 patent drawingFigure 3

AI summary

The present invention relates to a suction/return filter, comprising an inner filter arrangement at least comprising a filter head that can be interconnected in a fluid circuit and a filter base having a precharge/anti-cavitation valve for arrangement in an operating-medium tank. According to the invention, the precharge/anti-cavitation valve (4) has an inner valve seat (34), which can be partially closed by means of a valve seat body (36), and an outer valve seat (44), which can be fully closed by means of said valve seat body (36), wherein a spring-loaded seat valve (38, 40, 42) that permits only a fluid flow from the filter base into the operating-medium tank is integrated in the valve seat body (36).