Condensate discharge device for a heating device and heating device

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Solution Overview

Problem

Existing condensing boilers face issues with pressure-neutral condensate drainage and liquid backflow prevention, particularly when incorrectly installed, leading to potential damage from washing machine and dishwasher water being forced back into the boiler.

Innovation Solution

A condensate drain device comprising an inlet nozzle, backflow preventer, and drain siphon, designed as a module that ensures pressure-neutral drainage and prevents backflow using a self-contained, direction-sensitive valve and a bottle siphon to create a gas and odor barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the boiler's condensate drain is connected directly to washing machine/dishwasher drains without a sanitary siphon, then installation simplicity is improved, but liquid backflow into the boiler occurs causing damage

Engineering Contradiction:
Improveinstallation simplicityVSAvoidprotection against backflow
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The condensate drainage system is segmented into distinct functional components: the inlet nozzle for condensate entry, the backflow preventer with floating closure element for one-way flow control, and the drain siphon for pressure-neutral drainage. This segmentation allows each component to perform its specific function effectively, preventing backflow while maintaining installation simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The backflow preventer acts as an intermediary device between the boiler condensate drain and the household appliance drains. Its floating closure element automatically opens to allow condensate flow from the boiler to the drain, but closes to prevent liquid backflow from the drain into the boiler, thus mediating the interaction between these two systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a sanitary siphon is installed for pressure-neutral drainage, then protection against backflow is improved, but device complexity increases

Engineering Contradiction:
Improveprotection against backflowVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backflow preventer and drain siphon are merged into a single integrated condensate drainage device that can be directly connected to the boiler. This combination provides both backflow prevention and pressure-neutral drainage functions in one unit, eliminating the need for separate sanitary siphon installation while maintaining protection against backflow.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated condensate drainage device performs multiple functions: it serves as the condensate inlet, includes backflow prevention through the floating closure element, provides pressure-neutral drainage through the siphon effect, and creates a gas barrier. This multi-functionality reduces system complexity while maintaining reliability.

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

3Object-affected harmful factors

If the drain siphon forms a gas barrier, then prevention of gas leakage is improved, but device complexity increases

Engineering Contradiction:
Improvegas leakage preventionVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The gas barrier function is merged into the drain siphon component itself. The siphon's liquid seal naturally prevents gas passage while the same component provides pressure-neutral drainage. This integration avoids adding separate gas barrier devices, thereby preventing gas leakage without significantly increasing device complexity.

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

Ensures effective, pressure-neutral condensate drainage and prevents liquid backflow into the boiler, even with incorrect installations, while maintaining a gas and odor barrier.

Implementation Method 1

The drain siphon (5) forms a gas or odor barrier

Methodology Applied
Scientific EffectSiphon effect: Syphon

Implementation Method 2

With a bottle siphon, a pipe section ends in a bottle-shaped container containing (always) liquid. This liquid prevents gases from being passed through.

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP4417893B1Condensate discharge device for a heating device and heating device
Publication Date: 2026.04.29 VAILLANT GMBH(DE)
  • EP4417893B1 patent drawingFigure 1
  • EP4417893B1 patent drawingFigure 2
  • EP4417893B1 patent drawingFigure 3~4

AI summary

Condensate drain device (1) for a heating appliance (2), comprising an inlet nozzle (3), a backflow preventer (4) and a drain siphon (5).