Drain Fitting Non-Standardized Connection Prevents Backflow

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Solution Overview

Problem

Conventional drain fittings for bathtubs and shower trays often require a pipe interrupter or backflow preventer to prevent contamination of the drinking water supply, but these can be easily bypassed or incorrectly installed, leading to potential backflow issues.

Innovation Solution

The drain fitting features non-standardized connections between the drinking water safety fitting and the drain housing, utilizing press or plug connections with unique positive locking elements, ensuring that only compatible counterparts can be used, thereby preventing incorrect installation and ensuring a secure, leak-proof connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If standardized connections (1/2 inch or 3/4 inch) are used for the water inlet connection and drinking water safety fitting, then ease of installation and compatibility are improved, but the risk of incorrect installation and bypassing safety features increases

Engineering Contradiction:
Improveease of installationVSAvoidprevention of incorrect installation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connection design uses asymmetric positive locking elements (protrusions and recesses) that only fit together in the correct orientation and configuration. This asymmetric geometry prevents standardized connections from being mistakenly used, as only the specific non-standardized connection geometry will properly align and lock together, thereby preventing incorrect installation while maintaining installation ease through the simple plug-socket interface.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If non-standardized press connections with positive locking elements are used, then prevention of incorrect installation and backflow is improved, but device complexity increases

Engineering Contradiction:
Improveprevention of backflowVSAvoidconnection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection design merges multiple functions into a single integrated connection structure: the press-fit mechanism provides sealing, the positive locking elements (protrusions and recesses) provide mechanical interlocking and orientation guidance, and the overall geometry prevents mismatched connections. By combining these functions into one unified connection interface, the design achieves high reliability without proportionally increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connection uses specific dimensional parameters (protrusion height, recess depth, outer diameter, inner diameter) that are optimized to provide both sealing and mechanical locking. By carefully selecting these geometric parameters, the design achieves reliable backflow prevention through a connection structure that remains relatively simple in overall form.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If pipe interrupters are installed above the bathtub edge, then drinking water safety is improved, but installation space requirements and device complexity increase

Engineering Contradiction:
Improvedrinking water safetyVSAvoidinstallation configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drinking water safety function is merged with the existing water inlet connection structure. The non-standardized connection with positive locking elements serves dual purposes: it provides the mechanical connection for water supply and simultaneously acts as the safety mechanism preventing bypassing and backflow. This integration eliminates the need for separate pipe interrupters installed above the bathtub edge, reducing installation complexity while maintaining safety.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2495371B1Drainage fitting with a water intake channel for a floor intake
Publication Date: 2015.07.08 VIEGA GMBH & CO KG
  • EP2495371B1 patent drawingFigure 1
  • EP2495371B1 patent drawingFigure 2~3
  • EP2495371B1 patent drawingFigure 4~8

AI summary

The outlet fitting has a water inlet channel that is integrated on outlet housing (2) formed with water inlet connection (2.9). A removable cover (1) is connected with water inlet channel for covering drain hole. Back-flow preventer is arranged between the stop valve (12) and water inlet connection of the outlet housing. The output terminal of back-flow preventer and water inlet connection of the outlet housing are formed with predetermined size in predetermined manner. A water conduit is connected with back-flow preventer.