Hinged Flap Non-Return Valve for Heating System Backflow Prevention

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Solution Overview

Problem

Existing non-return valves in heating systems experience issues with noise, complex installation, and reduced user comfort due to noise and complex retrofitting, and are prone to backflow due to pressure fluctuations in multi-occupancy systems, requiring improved operational reliability and ease of installation.

Innovation Solution

A non-return valve with a rotatable flap part having increased deformability and a hinge region to adapt to uneven sealing surfaces, combined with a frame part for secure sealing and resistance to pressure surges, allowing easy installation and reliable sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-return valve is installed in the exhaust duct, then backflow prevention is improved, but noise is generated that reduces user comfort

Engineering Contradiction:
Improvebackflow preventionVSAvoidnoise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The non-return valve is extracted from the exhaust duct and relocated to the air supply line. This removes the noise-generating component from the exhaust system while preserving its backflow prevention function in the air supply path, thereby eliminating the harmful noise effect while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a non-return valve is installed in the exhaust duct, then backflow prevention is improved, but installation and retrofitting become complex

Engineering Contradiction:
Improvebackflow preventionVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The non-return valve is designed as a universal component that can be installed in the air supply line, which is a standard location in heater construction. This multi-functional placement allows the same valve design to serve both new installations and retrofits without requiring complex exhaust duct modifications, thereby simplifying installation while maintaining backflow prevention reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If a thin and lightweight non-return valve is used, then ease of operation is improved, but operational reliability deteriorates due to pressure fluctuations causing false opening

Engineering Contradiction:
Improvevalve operationVSAvoidbackflow prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The valve design parameters are optimized to achieve an optimal balance between weight and stiffness. The flap is designed with specific dimensional ratios and material properties that provide sufficient rigidity to resist pressure fluctuations from multi-occupancy systems, preventing false opening, while remaining lightweight enough to ensure easy operation and proper sealing contact with the sealing surface.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If a non-return valve is installed in the heater, then backflow prevention is improved, but inspection and retrofitting require opening the gas-air path which is complex

Engineering Contradiction:
Improvebackflow preventionVSAvoidinspection complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The non-return valve is extracted from the gas-air path and installed in the air supply line instead. This relocation allows the valve to be accessed and inspected independently without requiring opening of the gas-air path, thereby maintaining backflow prevention reliability while significantly simplifying inspection and retrofitting operations to tasks that can be performed by standard installers.

Inventive Principle:
Principle #2Taking out (Extraction)

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 provides high operational reliability, minimizes user discomfort, and ensures easy installation while maintaining effective sealing against backflow, even under pressure fluctuations.

Implementation Method 1

Compared to the segments of the flap part, the hinge region has increased deformability, particularly with respect to bending loads

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a flap part that can be rotated about a rotational axis and is designed to engage sealingly against a sealing element in a closed rotational position

Methodology Applied
Scientific EffectRotation:

Data Source

PatentEP4617585A1Backflow safety valve for a heating device, heating device and heating system
Publication Date: 2025.09.17 VAILLANT GMBH(DE)
  • EP4617585A1 patent drawingFigure 1~2
  • EP4617585A1 patent drawingFigure 3
  • EP4617585A1 patent drawing

AI summary

The invention relates to a non-return valve (1) for a heating system (2). Said valve comprises a flap part (12) which is rotatable about a rotational axis (15) and which, in a closed rotational position, is designed to engage sealingly against a sealing element (20). The flap part (12) has at least two segments (17, 19) which are connected to one another by at least one linear hinge region (16, 18). The hinge region (16, 18) has, compared to the segments (17, 19) of the flap part (12), an increased deformability with respect to bending loads. The hinge region (16, 18) comprises a closed, circumferential hinge (18) surrounding at least one central segment (19) and a plurality of edge hinges (16) which extend radially from the circumferential hinge (18) to an outer contour (23) of the flap part (12). The non-return valve (1) can therefore form a sealing effect even if the sealing surface is uneven and can still withstand pressure surges that occur.In addition, a heater (3) and a heating system (2) are proposed.