Two-Component Non-Return Valve Sealing for Exhaust Backflow

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Solution Overview

Problem

Existing heating devices connected to a shared exhaust system face the issue of exhaust gases escaping when one device is switched off, due to lack of back pressure, posing safety risks.

Innovation Solution

A non-return valve with a valve housing and closing body featuring a hard plastic part with an elastic soft seal, molded using a two-component injection molding process, ensures a captive and position-safe sealing surface, preventing exhaust gas flow between heating devices by being installed in the combustion air supply between the burner and fan, with the closing body positioned away from the blower to allow operation-induced opening and gravity-induced closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-return valve is installed to prevent exhaust gas flow, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the hard plastic valve body and elastic soft seal into a single integrated component using two-component injection molding. This merging of components achieves reliable sealing (improving safety) while reducing the number of separate parts and assembly steps (avoiding increased device complexity).

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite construction by molding an elastic soft seal onto a hard plastic valve body. This composite structure integrates the sealing function into the valve body itself, providing reliable sealing (improving safety) without requiring separate sealing components or complex assembly (avoiding increased device complexity).

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple sealing components are used to ensure tightness, then sealing reliability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the sealing function into the valve body by molding an elastic soft seal directly onto the hard plastic valve body. This single integrated component ensures tightness (improving sealing reliability) while eliminating the need for separate sealing components and complex assembly operations (improving ease of manufacture).

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The two-component injection molding process creates a composite structure where the elastic soft seal is permanently bonded to the hard plastic valve body. This ensures reliable sealing (improving sealing reliability) through a single manufacturing process rather than multiple assembly steps (improving ease of manufacture).

Inventive Principle:
Principle #40Composite materials

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 reliable sealing and prevents exhaust gas escape between heating devices, ensuring safety and easy assembly, with the elastic soft seal ensuring tightness and quiet operation, while the additional weight and hinge mechanism enhance sealing force and ease of movement.

Implementation Method 1

a hard plastic part with an elastic soft seal molded on using a two-component injection molding process

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

If the closing body has an additional weight, the sealing force can be increased

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2871393B1Return flow prevention
Publication Date: 2017.10.04 VAILLANT GMBH(DE)
  • EP2871393B1 patent drawingFigure 1
  • EP2871393B1 patent drawingFigure 2
  • EP2871393B1 patent drawingFigure 3

AI summary

In a non-return valve (1) with a valve seat (2) and a closing element (3), wherein the valve seat (2) has an opening (4) which can be closed by the closing element (3), the closing element (3) has a first hard plastic part (5) onto which a first elastic soft seal (6) is injection molded in a two-component injection molding process and/or the valve seat (2) has a second hard plastic part (8) onto which a second elastic soft seal (9) is injection molded in a two-component injection molding process.