Rail Vehicle Sand Dispenser Pneumatic Decoupling

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Solution Overview

Problem

Existing sanding devices for rail vehicles face challenges in accurately metering and conveying sand due to interactions between the dosing and conveying processes, which can be influenced by air pressure and flow differences, affecting the coefficient of friction between the wheel and rail.

Innovation Solution

A sanding device with a dosing device for pneumatically metering sand using a dosing air stream, a conveying device for pneumatically conveying sand to spreading points using a conveying air stream, and a decoupling device that compensates for airflow differences between the dosing and conveying devices using a compensating air flow, ensuring independent operation and minimizing wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the dosing device and conveying device are operated together using compressed air, then sand can be delivered to the spreading point, but air pressure and flow differences cause interactions that affect dosing precision

Engineering Contradiction:
Improvesand deliveryVSAvoiddosing precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system is divided into three independent functional modules: dosing device (104), conveying device (106), and decoupling device (108). This segmentation allows each module to operate independently with its own air supply, eliminating the interaction problem where conveying air pressure affects dosing precision. The dosing device uses dosing air stream while the conveying device uses conveying air stream, and the decoupling device ensures air quantity equalization between them.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoupling device acts as an intermediary between the dosing device and conveying device. It receives air from both devices and performs pressure equalization and air quantity equalization, compensating for differences in outlet air flow from the dosing device and inlet air flow to the conveying device. This mediator prevents the harmful interaction while maintaining overall system functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If different amounts of air are used to transport sand under different conditions, then sand delivery can be adapted, but metering of the sand amount is influenced by air flow variations

Engineering Contradiction:
Improvesand delivery adaptationVSAvoidsand metering precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts air flow amounts based on different operating conditions. The dosing device can use different dosing air stream quantities, and the conveying device can use different conveying air stream quantities, allowing adaptation to various sand delivery requirements. The decoupling device dynamically equalizes the air quantities between these devices, ensuring that metering precision is maintained regardless of the total air flow amount used for transport.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the dosing process and conveying process are coupled, then system complexity is reduced, but overpressure or negative pressure differences occur between devices

Engineering Contradiction:
Improvesystem structureVSAvoidpressure stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The decoupling device serves as a pressure equalization intermediary between the dosing device and conveying device. It receives air from both devices and equalizes the pressure, preventing overpressure or negative pressure differences that would occur if the devices were directly coupled. This maintains reliability while keeping the overall system structure relatively simple through the use of a single intermediate component.

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 decouples the dosing and conveying processes, allowing for precise sand delivery and minimizing wear, while maintaining a consistent coefficient of friction between the wheel and rail, even under varying conditions.

Implementation Method 1

a dosing device for pneumatically dosing a desired amount of sand using a dosing air stream

Methodology Applied
Scientific EffectPneumatic transport: Pressure Gradient

Implementation Method 2

a conveying device for pneumatically conveying the amount of sand to at least one spreading point using a conveying air stream

Methodology Applied
Scientific EffectPneumatic transport: Pressure Gradient

Implementation Method 3

a decoupling device for pneumatically decoupling the metering device and the delivery device, wherein the decoupling device is designed to provide a compensating air flow to compensate for a difference between an outlet air flow of the metering device and an inlet air flow of the delivery device

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP3052367B1Sand dispenser for a rail vehicle and method for providing sand for a rail vehicle
Publication Date: 2020.01.15 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3052367B1 patent drawingFigure 1~2
  • EP3052367B1 patent drawingFigure 3~4
  • EP3052367B1 patent drawingFigure 5~6

AI summary

The present invention relates to a sand dispenser (100) for a rail vehicle (102), wherein the sand dispenser (100) comprises a metering device (104), a delivery device (106) and an uncoupling device (108). The metering device (104) is designed to pneumatically meter a desired quantity of sand using a metering air flow (110). The delivery device (106) is designed to pneumatically deliver the quantity of sand to at least one scattering site (126) using a delivery air flow (124). The uncoupling device (108) is designed to pneumatically uncouple the metering device (104) and the delivery device (106), wherein the uncoupling device (108) is designed to provide a compensating air flow (138) for compensating a difference between an output air flow (122) of the metering device (104) and an input air flow (134) of the delivery device (106).