Rail Vehicle Tank Drainage Thermal Switch Control

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Solution Overview

Problem

Existing tank emptying devices for rail vehicle fresh water tanks are not energy-efficient and prone to false triggering, leading to unnecessary drainage and prolonged vehicle downtime due to inaccurate temperature sensing and continuous power consumption.

Innovation Solution

A tank emptying device with a precision thermal switch and timer mechanism that opens a drain valve only when the tank temperature falls below a specific threshold, eliminating the need for level measurement sensors and optimizing energy use by switching the power supply only during operation, with the thermal switch positioned on the drain line to detect freezing early and control the emptying process accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional thermal switches with large hysteresis are used, then the device is simpler and more reliable, but the switching point accuracy deteriorates causing false triggering at temperatures significantly higher than required

Engineering Contradiction:
Improveswitching point accuracyVSAvoidthermal switch precision requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by selecting a thermal switch with specific precision parameters (hysteresis less than 5 Kelvin, switching point accuracy within 1-3 degrees Celsius). This resolves the contradiction by changing the thermal switch's operational parameters to achieve accurate temperature detection near freezing without requiring complex additional sensing systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If level measurement sensors are installed to detect tank emptying, then the filling level can be monitored, but energy consumption increases due to continuous operation of ultrasonic sensors

Engineering Contradiction:
Improvetank emptying detection accuracyVSAvoidpower consumption of level sensors
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the level measurement function from the system. By placing the thermal switch directly on the drain line, the system eliminates the need for separate ultrasonic level sensors, thereby removing the continuous energy consumption associated with level detection while maintaining reliable emptying detection through temperature-based triggering.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thermal switch serves multiple functions: it detects both the temperature condition for emptying initiation and indirectly indicates tank emptying status. This multi-functionality eliminates the need for dedicated level sensors, reducing energy consumption while maintaining detection reliability.

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

3Measurement precision

If the thermal switch is positioned in the tank to monitor water temperature, then accurate temperature sensing is achieved, but the device fails to detect early freezing conditions on the drain line

Engineering Contradiction:
Improvefreezing detection accuracyVSAvoidresponse time to freezing condition
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by positioning the thermal switch on the drain line where freezing occurs first. This allows the system to detect freezing conditions before they affect the tank interior, providing early warning and enabling preventive emptying action. The thermal switch is placed in the location where the harmful freezing process begins, allowing early detection and intervention.

Inventive Principle:
Principle #10Preliminary 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 ensures precise and energy-efficient emptying of the tank, reducing false alarms and extending the battery life by accurately initiating drainage near freezing temperatures, thus minimizing downtime and maintenance costs.

Implementation Method 1

a thermal switch (7) which is thermally coupled to the fresh water

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the thermal switch is arranged on a drain line (4)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2904156B1Tank drainage device
Publication Date: 2020.03.11 SIEMENS MOBILITY AUSTRIA GMBH
  • EP2904156B1 patent drawingFigure 1
  • EP2904156B1 patent drawingFigure 2~3

AI summary

A tank drainage device for a fresh water tank (1) on a rail vehicle, wherein a thermostatic switch (7) is thermally coupled to the fresh water and, in the event of the temperature in the tank (1) falling below a predefined temperature, triggers a timing element (6), which thereby opens a drainage valve (2) for a predefined period, wherein the thermostatic switch (7) is arranged on a drainage line (4).