Interlocking Control Device for Multiple-Unit Train Safety Circuit
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Solution Overview
Problem
Existing interlocking control devices for multiple-unit safety circuits do not adequately ensure the safety of operating personnel and equipment during inspection and maintenance of high-voltage equipment on multiple-unit trains, as they fail to prevent current flow through the high-voltage circuit when the pantograph should not be operational.
Innovation Solution
An interlocking control device is introduced, featuring a protective grounding switch control branch with a pantograph rising pneumatic circuit cut-off valve, a protective grounding switch turn-off pneumatic circuit cut-off valve, and a solenoid valve, which maintains the protective grounding switch in an on state during inspection or external power supply, preventing the pantograph from rising and ensuring no current flows through the high-voltage circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pantograph is allowed to rise for normal operation, then power supply to the train is ensured, but current may flow through the high-voltage circuit during maintenance creating safety hazards
Solution Approach 1:
The key is locked in the key box before maintenance begins, preventing any subsequent operation of the protective grounding switch. This preliminary action ensures that once the key is removed for maintenance, the pantograph cannot rise and the high-voltage circuit remains de-energized throughout the maintenance period, eliminating safety hazards while maintaining operational simplicity
Solution Approach 2:
The key box acts as an intermediary device that physically connects the key removal action to the locking of pneumatic circuit cut-off valves. This intermediary mechanism ensures that the protective grounding switch remains in the on state throughout maintenance, providing automatic safety interlocking without requiring complex control systems
2Reliability
If the protective grounding switch is manually controlled, then operational flexibility is maintained, but accidental activation during maintenance may occur causing safety risks
Solution Approach 1:
The system uses the key itself as the control element - removing the key from the key box automatically triggers the locking mechanism through the pneumatic circuit cut-off valves. This self-service approach eliminates the need for separate control systems or complex interlocking mechanisms while ensuring reliable prevention of pantograph activation during maintenance
Solution Approach 2:
The patent employs pneumatic circuit cut-off valves to transmit the key removal signal to the protective grounding switch mechanism. This pneumatic transmission provides reliable, fail-safe control without requiring complex electrical interlocking systems, reducing device complexity while maintaining high reliability
3Reliability
If keys are kept accessible for quick operation, then response time is reduced, but unauthorized or accidental access during maintenance becomes possible
Solution Approach 1:
The key is removed from the key box and retained by the operator before maintenance begins. This preliminary action ensures that the key cannot accidentally or unauthorizedly activate the protective grounding switch during maintenance, while the operator retains immediate access to the key for legitimate operations after maintenance is complete
Solution Approach 2:
The key is extracted from the key box and held by the operator during maintenance operations. This extraction removes the key from any position where it could accidentally trigger the protective grounding switch, while maintaining quick access for the operator who has the key in hand, thus resolving the contradiction between safety and response time
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 maintains the protective grounding switch in an on state, preventing the pantograph from rising and ensuring personal safety by providing a low-impedance current path for high-voltage circuits during maintenance, thus ensuring the safety of maintenance personnel.
Implementation Method 1
a pantograph rising pneumatic circuit cut-off valve, a protective grounding switch turn-off pneumatic circuit cut-off valve and a protective grounding switch turn-off solenoid valve which are connected in series
Implementation Method 2
a protective grounding switch turn-off solenoid valve which are connected in series
Implementation Method 3
the cover of the key box is mechanically locked by means of the pantograph rising pneumatic circuit cut-off valve and the protective grounding switch turn-off pneumatic circuit cut-off valve
Implementation Method 4
providing a low-impedance current path for high-voltage circuits during maintenance
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An interlocking control device for a multiple-unit train safety circuit comprises a protective grounding switch control branch that comprises a pantograph rising pneumatic circuit cut-off valve (J1), a protective grounding circuit turn-off pneumatic circuit cut-off valve (J2), and a protective grounding switch turn-off solenoid valve (Y1) which are connected in series; when high-voltage equipment of the multiple-unit train is under repair and maintenance or an external power supply supplies power, the protective grounding switch is operated to be closed, a cock of the pantograph rising pneumatic circuit cut-off valve (J1) and a cock of the protective grounding circuit turn-off pneumatic circuit cut-off valve (J2) are rotated to open the cover of a key cabinet; in addition, the protective grounding switch control branch is disconnected, the protective grounding switch turn-off solenoid valve (Y1) connected in series in the protective grounding switch control branch loses power, so that the protective grounding switch is closed; the cover of the key cabinet is mechanically locked by means of the pantograph rising pneumatic circuit cut-off valve (J1) and the protective grounding circuit turn-off pneumatic circuit cut-off valve (J2). When high-voltage equipment is under repair and maintenance or an external power source supplies power, a protective grounding switch needs to be kept closed, thereby protecting the safety of maintenance personnel.