Rail Toilet Filter Backflushing for Clog Prevention

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Solution Overview

Problem

Compact vacuum toilets in rail vehicles face clogging issues due to foreign bodies in the water supply, leading to system failures and increased maintenance requirements, which are exacerbated by variable land-side infrastructure conditions.

Innovation Solution

A toilet facility design with a filter system that includes a backwash line to clean the filter by reversing the rinsing water flow through the filter and into the waste water-carrying installations, reducing maintenance needs and ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fine-mesh filter is installed in the water supply line to prevent clogging, then the reliability of the toilet system is improved, but the filter requires regular cleaning and replacement which increases maintenance requirements

Engineering Contradiction:
Improvereliability of toilet systemVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The filter cleans itself automatically by utilizing the existing flushing water system. During normal operation, flushing water flows through the filter in reverse direction, removing accumulated particles and debris without requiring manual intervention. This self-cleaning mechanism maintains filter effectiveness while eliminating the need for regular maintenance shutdowns.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements periodic backflushing cycles where the flow direction through the filter is reversed at scheduled intervals. This periodic reverse flow automatically removes accumulated particles from the filter mesh, restoring filtering capacity without manual intervention and preventing clogging before it affects system reliability.

Inventive Principle:
Principle #19Periodic action

2Ease of repair

If the filter is positioned within the piping system for easy maintenance, then the ease of repair is improved, but the device complexity increases due to considerable design effort

Engineering Contradiction:
Improveaccessibility of filterVSAvoidpiping system design
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The filter is integrated directly into the existing piping system rather than being installed as a separate maintenance component. The filter housing becomes part of the pipe structure itself, with the backflushing mechanism utilizing existing water lines and valves. This merging eliminates additional design complexity while maintaining ease of maintenance through the automatic backflushing process.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If preventive maintenance intervals are set short to ensure reliable operation under adverse conditions, then the reliability is improved, but the loss of time for maintenance increases

Engineering Contradiction:
Improvereliability under adverse conditionsVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The automatic backflushing system performs maintenance continuously during normal operation without requiring scheduled shutdowns. The filter cleans itself during each flushing cycle, eliminating the need for manual maintenance interventions regardless of water quality conditions. This eliminates maintenance time loss while ensuring continuous reliability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The backflushing process occurs continuously during normal toilet operation rather than requiring periodic shutdowns for maintenance. Each flush contributes to cleaning the filter, maintaining its effectiveness continuously without interrupting toilet service. This continuous maintenance action eliminates downtime while ensuring reliable operation under all conditions.

Inventive Principle:
Principle #20Continuity of useful action

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 effectively prevents clogging and reduces maintenance efforts by automatically cleaning the filter, enhancing the reliability and cost-effectiveness of the toilet facility despite varying water quality and infrastructure conditions.

Implementation Method 1

For cleaning the at least one filter, the at least one supply line is connected to the at least one intermediate tank in such a way that flushing water from the intermediate tank can be returned through the filter

Methodology Applied
Scientific EffectReverse flow:

Data Source

PatentEP3164314B1Toilet device having a backflushing function for a particle filter
Publication Date: 2020.03.25 SIEMENS MOBILITY GMBH
  • EP3164314B1 patent drawingFigure 1~2
  • EP3164314B1 patent drawingFigure 3~4
  • EP3164314B1 patent drawingFigure 5~6

AI summary

The invention relates to a toilet device for a rail vehicle, comprising flushing water-carrying installations and wastewater-carrying installations, the flushing water-carrying installations comprising an intermediate reservoir (7) for storing flushing water and a supply line (1, 2) for supplying the intermediate reservoir (7) with flushing water. The supply line (1, 2) comprises a filter (14) for filtering the flushing water supplied to the intermediate reservoir, the supply line (1, 2) being connected to the intermediate reservoir (7) such that flushing water from the intermediate reservoir (7) can be returned through the filter, the toilet device comprising a backflushing line (3) which is connected to the filter (14) and which opens into a wastewater-carrying installation. The invention further relates to a method for operating said toilet device, comprising the following steps: a) filling the intermediate reservoir (7) with flushing water, the flushing water supplied to the intermediate reservoir (7) being conducted through a filter (14); b) flushing a flushable bowl (12) with flushing water from the intermediate reservoir (7) or c) backflushing the filter (14) with flushing water from the intermediate reservoir (7) and draining off the flushing water to a wastewater-carrying installation.