Series Valve Assembly with Venting for Backflow Prevention

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Solution Overview

Problem

Existing valve arrangements for connecting low-pressure and high-pressure areas in fluid systems are not completely tight, leading to backflow and contamination, which poses safety risks and can cause malfunctions, especially at high pressures.

Innovation Solution

A valve arrangement comprising a first valve that closes automatically when pressure from the high-pressure area equals or exceeds the low-pressure area, coupled with a second valve that also closes and a third valve that opens to vent fluid to a lower pressure area, preventing backflow and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an automatic non-return valve is used to prevent backflow, then backflow prevention is improved, but the valve is not completely tight leading to creeping flows at high pressure

Engineering Contradiction:
Improvebackflow preventionVSAvoidcreeping flows
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The shut-off device is divided into two separate valves (first shut-off valve and second shut-off valve) positioned in series between the low-pressure and high-pressure areas. This segmentation ensures that if one valve has imperfections or creeping flows, the other valve provides an additional barrier, achieving complete backflow prevention without substance loss.

Inventive Principle:
Principle #1Segmentation

2Stress or pressure

If a safety valve is used to prevent excess pressure, then pressure control is improved, but contamination of the low-pressure area cannot be prevented

Engineering Contradiction:
Improvepressure controlVSAvoidcontamination
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

Two shut-off valves are positioned in series to create multiple barriers between the high-pressure and low-pressure areas. This segmentation prevents contamination by ensuring that even if pressure control is adequate, harmful substances cannot penetrate through both tightly sealed valves to reach the low-pressure area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shut-off valves are designed to close automatically when pressure differences indicate potential backflow or contamination risk, before actual contamination can occur. This preliminary action prevents harmful substances from reaching the low-pressure area while maintaining pressure control.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If two shut-off valves connected in series are used, then complete shut-off is achieved, but device complexity increases

Engineering Contradiction:
Improveshut-off completenessVSAvoidvalve arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses two simple shut-off valves in series rather than one complex valve. This segmentation achieves complete shut-off reliability while keeping individual valve components simple and manageable, balancing reliability improvement with acceptable device complexity.

Inventive Principle:
Principle #1Segmentation

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 complete shut-off between the pressure areas, preventing fluid backflow and contamination, even if the valves are not completely tight, and effectively manages pressure exceeding the design limits, thereby enhancing safety and system reliability.

Implementation Method 1

The first valve is configured to close when a pressure applied to the second pressure range side is at least as high as a pressure applied to the first pressure range side

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

A third valve connects an area between the first and the second valve to a third pressure area in which the pressure, in particular the operating pressure, is in particular lower than in the first pressure area

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP2930407B1Valve assembly
Publication Date: 2017.01.25 LINDE AG
  • EP2930407B1 patent drawingFigure 1
  • EP2930407B1 patent drawingFigure 2~3

AI summary

The invention relates to a valve arrangement (200) for a fluid-operated system for connecting a first pressure region (p1) with a second pressure region (p2) by means of a first valve (10) and a second valve (20) connected in series therewith, wherein a third valve (30) connects a region (p1/2) between the first valve (10) and the second valve (20) with a third pressure region (p3); wherein the first valve (10) is configured to close when a pressure applied on the side of the second pressure region (p2) is at least as high as a pressure applied on the side of the first pressure region (p1); wherein the first valve (10) is coupled to the second valve (20) such that the second valve (20) closes when the first valve (10) closes; and wherein the second valve (20) is coupled to the third valve (30) such that the third valve (30) opens when the second valve (20) closes.