Nested Dual Check Valve Structure for Foreign-Matter Leak Backup

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Solution Overview

Problem

Conventional check valve devices with multiple valves in a flowpath are prone to leaks due to foreign matter interference, leading to pressurized fluid leakage when one or both valves cannot close properly.

Innovation Solution

A check valve device with a main valve and a sub-valve arranged in series, where one valve closes if the other fails to prevent leakage, and a pilot valve controls the opening and closing of both valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple valves are provided in a flowpath to control fluid flow, then the valve can effectively block pressurized fluid when closed, but the probability of valve failure due to foreign matter increases, leading to pressurized fluid leakage

Engineering Contradiction:
Improvevalve closing reliabilityVSAvoidforeign matter interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sub-valve member is nested inside the main valve member, with the sub-valve positioned within the main valve's cylindrical hole. This nested configuration allows both valves to occupy the same flowpath space, enabling series arrangement without significantly increasing device volume. When the sub-valve fails to close due to foreign matter, the main valve provides backup sealing, and vice versa, thus resolving the contradiction between reliability and susceptibility to foreign matter interference.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention provides a backup valve mechanism in advance to compensate for potential valve failure. By arranging the main valve and sub-valve in series, the system预先 (in advance) prepares a redundant sealing mechanism that can compensate if one valve fails due to foreign matter or other issues, thus cushioning against the harmful effects of valve failure before they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If two valves are arranged in series in one flowpath, then backup sealing is provided against leakage, but the device complexity and space occupation increase

Engineering Contradiction:
Improveleakage preventionVSAvoidvalve structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sub-valve member is nested inside the main valve member, with the sub-valve positioned within the main valve's cylindrical hole. This nested configuration allows both valves to occupy the same flowpath space, enabling series arrangement without significantly increasing device volume. When the sub-valve fails to close due to foreign matter, the main valve provides backup sealing, thus resolving the contradiction between reliability and susceptibility to foreign matter interference.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If conventional separate valve arrangements are used, then each valve operates independently, but pressurized fluid leaks when either valve fails to close

Engineering Contradiction:
Improvevalve operation independenceVSAvoidpressurized fluid sealing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention merges the main valve and sub-valve into a single integrated valve assembly where both valves share the same flowpath and are controlled by a common pilot valve. This merging allows the valves to operate independently for sealing purposes while being coordinated by the pilot valve, providing backup sealing capability without requiring complex independent control systems.

Inventive Principle:
Principle #5Merging (Combining)

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

Prevents pressurized fluid leakage by ensuring at least one valve remains closed even if the other fails, reducing pressure loss and wear due to chattering.

Implementation Method 1

A valve closing spring (47) is mounted between the main valve member (41) and the block (1), and the valve closing spring (47) urges the main valve member (41) toward the main valve seat (46)

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 2

When pressurized fluid is supplied to the actuation chamber (76), the pilot valve member (63) is moved toward the sub-valve member (50)

Methodology Applied
Scientific EffectPressure force: Pressure Increase

Implementation Method 3

The pilot valve member (63) is urged away from the sub-valve member (50) by a retreating spring (66)

Methodology Applied
Scientific EffectElastic force: Spring

Data Source

PatentEP4421363B1Check valve device
Publication Date: 2026.03.18 KOSMEK LTD (JP)
  • EP4421363B1 patent drawingFigure 1
  • EP4421363B1 patent drawingFigure 2
  • EP4421363B1 patent drawingFigure 3

AI summary

Provided is a check valve device having a structure with which pressurized fluid is less likely to leak from a flowpath blocked by a valve. A flowpath 2 is formed in a block 1, and a main valve 3 and a sub-valve 4 are provided in series along the flowpath 2. A primary-side chamber 5, an intermediate chamber 7, and a secondary-side chamber 6, which form a section of the flowpath 2, are formed in that order from the one end of the flowpath 2 to the other end thereof. The main valve 3 and the sub-valve 4 are opened by a pilot valve 60.