Rail Control Valve Minimum Pressure Limiting via Accumulator
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Solution Overview
Problem
Existing control valves for rail vehicle compressed air brakes require additional valve components to implement minimum pressure limitation, making the process complex and maintenance-intensive.
Innovation Solution
Incorporating a brake nozzle in the boost pressure line and connecting an MDB pressure accumulator between the maximum pressure limiter and the ventilation connection, allowing the MDB pressure accumulator to supply pilot pressure unthrottled during braking, and then throttling it via the maximum pressure limiter, eliminates the need for additional valve components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional valve components are used to implement minimum pressure limitation, then the minimum pressure control function is achieved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The invention extracts the minimum pressure limitation function from the main valve body by using a separate, simple pressure accumulator (Druckakkumulator) connected to the pilot pressure line. This accumulator independently provides the minimum pressure without requiring additional valve components within the main valve assembly, thereby achieving the control function while minimizing device complexity
Solution Approach 2:
The pressure accumulator acts as an intermediary element between the main air line and the pilot pressure chamber. It mediates the pressure control by storing compressed air and releasing it to maintain the minimum pilot pressure, thereby implementing the minimum pressure limitation function without direct intervention from additional valve mechanisms
2Adaptability or versatility
If additional valve components are added for minimum pressure limitation, then the pressure control capability is improved, but the maintenance burden increases
Solution Approach 1:
By extracting the minimum pressure limitation function into a separate pressure accumulator, the invention eliminates the need for complex valve mechanisms that would require maintenance. The accumulator is a simple, robust component with no moving parts or seals that wear out, significantly reducing the maintenance burden while preserving full pressure control capability
Solution Approach 2:
The pressure accumulator is designed as a maintenance-free component that automatically maintains the minimum pilot pressure through its pre-charged air spring mechanism. It requires no adjustment, lubrication, or replacement of wear parts, thereby eliminating maintenance activities while providing adaptable pressure control
3Device complexity
If a simple minimum pressure limitation is implemented without additional valve means, then the device complexity is reduced, but the ability to provide rapid unthrottled pilot pressure may be compromised
Solution Approach 1:
The pressure accumulator is pre-charged with compressed air to a pressure higher than the maximum operating pilot pressure. This preliminary action ensures that when minimum pressure limitation is needed, the accumulator can immediately deliver unthrottled pilot pressure without waiting for throttling processes, thereby maintaining rapid response speed while using a simple device
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 enables simple and maintenance-free minimum pressure limitation, ensuring rapid brake engagement without additional valve means, with the MDB pressure accumulator providing unthrottled pilot pressure initially and throttled pressure thereafter, based on the selected mode.
Implementation Method 1
an MDB pressure accumulator is connected to the boost pressure line for minimum pressure limitation between the brake nozzle and the ventilation R connection on the control valve, so that when braking, the MDB pressure accumulator initially feeds the pilot pressure CV unthrottled, after which the maximum pressure limiter HDB feeds the pilot pressure CV via the brake nozzle in a throttled manner
Data Source
Figure 1
AI summary
The valve has a main air line (HL) for providing a pneumatic brake signal applied by a control piston (1) for actuating a valve mechanism (2). A supply pressure spacer (4) is inserted between a maximum relief valve (HDB) and a ventilation terminal (R) of a brake nozzle (5). A pressure reservoir (6) is attached to the supply pressure spacer to provide minimum pressure confinement between the nozzle and the terminal such that the reservoir is unthrottled with high-speed brakes to feed pilot pressure (CV) according to which the relief valve feeds the pilot pressure over the brake nozzle. An independent claim is also included for a method for operating a control valve.