Dual 4/2 Safety Valve Layout for Redundant Drive Isolation
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Solution Overview
Problem
Existing safety valve devices for fluid-actuated drives lack a reliable mechanism to ensure safe operation and redundancy, particularly in preventing uncontrolled movements and facilitating system diagnosis.
Innovation Solution
A safety valve device with two 4/2-way safety valves interconnected in a specific fluidic configuration, allowing activation only when both are in their second switching state, ensuring redundancy and preventing fluidic activation if they are in different states, with each valve having a control structure and seal system to manage fluid connections and prevent uncontrolled movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two safety valves are fluidically interconnected in series to provide redundancy, then the safety function is improved, but the device complexity increases
Solution Approach 1:
The safety valve device is segmented into two separate safety valves (first safety valve and second safety valve) that are fluidically interconnected in series. Each safety valve independently performs the same safety function, creating redundancy without requiring a completely new system architecture. This segmentation allows the safety function to be distributed across multiple identical components, improving reliability while maintaining manageable complexity through modular design.
2Reliability
If the safety valves are configured to require both valves to be in the second switching state for activation, then the safety function is improved, but the ease of operation deteriorates
Solution Approach 1:
The system is configured with preliminary anti-action by requiring both safety valves to be in the second switching state simultaneously for drive activation. This creates a built-in safety mechanism where the default state prevents activation, and activation requires a specific dual-state configuration. The control system monitors the switching states of both valves and only permits drive activation when both are in the permissive second state, thereby preventing unintended activation while maintaining operational control.
3Reliability
If the valve member is designed to extend into the receptacle space end section without sealing contact in the open position, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The valve member design inverts the traditional sealing approach: instead of the valve member maintaining continuous sealing contact with the valve housing in the open position, the valve member extends into the receptacle space end section without sealing contact. The sealing function is achieved through the seal element that engages with the valve seat when the valve member is in the closed or partially open position. This inversion allows the valve member to be freely positioned in the open state while maintaining sealing integrity through the separate seal mechanism, reducing manufacturing precision requirements for the valve member-housing interface.
Data Source
AI summary
A safety valve which has two fluidically interconnected safety valves, each of which has a 4/2-way valve function. Each safety valve has a first connecting port and a second connecting port, which are connected to each other in such a way that a fluid flow through the two safety valves, controlled by means of a control valve, to a fluid-actuated drive is prevented if the two safety valves simultaneously adopt a first switching position and such a fluid flow is possible if both valves simultaneously have a second switching state. One safety aspect results from the fact that the above-mentioned fluid flow is also prevented if the two safety valves adopt different switching states.