Rail Vehicle Extraction Pipe Anti-Freezing Design

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Solution Overview

Problem

Rail vehicle suction lines often retain residual waste water, which can freeze and clog, leading to operational issues and maintenance challenges, especially in vehicles with complex line configurations like double-deckers where the suction line cannot be easily positioned as the lowest point.

Innovation Solution

Incorporating a compressed air line connected to the suction line via a shut-off valve, allowing compressed air to be introduced into the suction line when closed, forcing residual waste water back into the waste water tank, thereby preventing freezing and clogging, and allowing for more flexible line routing without structural changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the suction line is routed with the suction port at the lowest point, then easy pumping is achieved, but the vehicle's contours and operational requirements cannot be met

Engineering Contradiction:
Improveeasy pumpingVSAvoidvehicle contour adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The suction line is divided into segments with different functions: a suction segment for pumping wastewater and a return segment for draining residual water. The shut-off valve segments the line to control flow direction, allowing the same physical line to serve multiple operational purposes depending on valve position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of always pumping from low to high, the system inverts the flow direction by closing the shut-off valve and using compressed air to push residual wastewater from the suction port back toward the tank through the return line. This reverse flow enables complete emptying despite the suction port being positioned high on the vehicle.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If the suction port is positioned high on the vehicle, then vehicle contour requirements are met, but residual wastewater remains in the suction line causing freezing and clogging

Engineering Contradiction:
Improvevehicle contour adaptabilityVSAvoidsuction line reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary emptying action by introducing compressed air into the suction line before residual wastewater can freeze or cause blockages. The compressed air pushes the residual water back into the tank proactively, preventing harmful effects before they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The compressed air system, which could be seen as an additional component increasing complexity, actually simplifies the overall system by eliminating the need for complex heating or insulation measures to prevent freezing. The harmful residual water is converted into a manageable flow that can be easily pushed back into the tank.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If a mobile suction system with small container is used, then flexibility is improved, but the suction pipe remains filled with residual wastewater when the container is full

Engineering Contradiction:
Improvemobile operation flexibilityVSAvoidresidual wastewater in pipe
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The system maintains continuous usefulness by enabling complete emptying of the suction line both during and after the pumping operation. The shut-off valve and compressed air system ensure that no wastewater remains in the line when the mobile container is full or when operations pause, ready for the next pumping cycle.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The suction line self-drains by using the same compressed air system that powers the pumping operation to push residual water back into the tank. The system serves itself by using its own resources (compressed air) to eliminate the problem of residual wastewater without requiring external intervention.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If the suction line is made long or complicated to reach the suction port, then vehicle contour requirements are met, but emptying the suction line becomes difficult

Engineering Contradiction:
Improverouting flexibilityVSAvoidline emptying ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The suction line serves multiple functions: it pumps wastewater from the tank to the suction port during operation, and it drains residual water back to the tank when emptying is required. The same physical infrastructure handles both directions of flow, eliminating the need for separate drain lines and simplifying the overall system.

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

Solution Approach 2:

The shut-off valve acts as an intermediary that controls flow direction in the suction line. By positioning the valve at strategic locations, it mediates between the tank and suction port, enabling the line to be filled for pumping and emptied for drainage using the same physical pathway.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution effectively removes residual waste water from the suction line, reduces the risk of freezing and clogging, enhances operational safety, and provides flexibility in line planning, allowing for efficient and safe emptying of the suction line without external compressed air supply.

Implementation Method 1

A compressed air line (40) connected to the suction line (20) via a shut-off valve (22), wherein compressed air can be introduced into the suction line (20) when the shut-off valve (22) is closed

Methodology Applied
Scientific EffectCompressed air pressure: Pressure Increase

Implementation Method 2

allowing compressed air to be introduced into the suction line when closed, forcing residual waste water back into the waste water tank

Methodology Applied
Scientific EffectFluid displacement: Pressure Gradient

Data Source

PatentEP3697665B1Rail vehicle having an extraction pipe
Publication Date: 2021.08.04 SIEMENS MOBILITY GMBH
  • EP3697665B1 patent drawingFigure 1
  • EP3697665B1 patent drawingFigure 2
  • EP3697665B1 patent drawingFigure 3

AI summary

The invention relates to a rail vehicle (1) which has a waste water tank (10), an extraction pipe (20) which is connected to the waste water tank (10) and leads from the waste water tank (10) to an extraction connection (30) for extracting the waste water, and comprises a shut-off valve (22) which is introduced into the extraction pipe (20) and which, in an opened state, opens the extraction pipe (20) and, in a closed state, closes the extraction pipe (20). Furthermore, the rail vehicle (1) comprises a compressed air pipe (40), which is connected via a compressed air connection (42) to the extraction pipe (20) and, in the closed state of the shut-off valve (22), is configured to introduce compressed air into the extraction pipe (20) via the compressed air connection (42), the compressed air connection (42) being positioned between the shut-off valve (22) and the waste water tank (10).