Quad-redundant Voting Solenoid System for Low Spurious Tripping
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Solution Overview
Problem
Existing solenoid valve configurations in process control systems face challenges in balancing safety and spurious trip rates, with complex installations and maintenance requirements, and a need for on-line testing without process interruption.
Innovation Solution
A '2 out of 4' voting solenoid arrangement with parallel solenoid valve pairs that selectively apply fluid pressure above and below a threshold, allowing for on-line testing and maintenance without disrupting the process, using a configuration with four solenoid valves where at least three must be actuated to maintain fluid flow and ensuring safety by dropping pressure only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a '1 out of 2' voting solenoid valve arrangement is used, then safety is improved, but spurious trip rate increases
Solution Approach 1:
The system divides the four solenoid valves into two independent parallel pairs (first pair: valves 40, 42; second pair: valves 44, 46). Each pair functions as an independent voting unit where both valves must be de-energized to cause a trip. This segmentation reduces spurious trips because a single valve failure within a pair cannot trigger shutdown, while maintaining safety through the dual-pair redundancy.
2Object-generated harmful factors
If a '2 out of 2' voting solenoid valve arrangement is used, then spurious trip rate is reduced, but safety testing requires process interruption
Solution Approach 1:
The patent introduces intermediary maintenance block valves (22, 24) and isolation valves (30, 32) that act as mediators between the solenoid valve pairs and the trip header. These intermediaries enable independent testing of each valve pair by isolating one pair from the trip header while the other pair remains operational, allowing safety verification without process interruption.
Solution Approach 2:
The system dynamically reconfigures its operational state during maintenance by using maintenance block valves to isolate and deactivate one valve pair while the other pair continues to protect the process. This dynamic switching capability allows frequent safety testing without requiring complete system shutdown, addressing the testing capability limitation.
3Reliability
If a quad voting solenoid configuration is used, then safety and reliability are improved, but device complexity and maintenance difficulty increase
Solution Approach 1:
The four solenoid valves are segmented into two identical parallel pairs with symmetric wiring and control logic. Each pair operates as a modular unit with the same electrical connections and hydraulic pathways. This segmentation simplifies installation by allowing repetitive modular assembly and reduces maintenance complexity by enabling independent servicing of one pair without affecting the other.
Solution Approach 2:
The patent merges the functionality of four solenoid valves into two parallel pairs that share common hydraulic connections to the trip header. The maintenance block valves and isolation valves are merged into the existing hydraulic manifold structure, reducing the need for separate complex piping and simplifying overall system integration while maintaining quad-redundant safety functionality.
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 provides high safety with low spurious tripping rates, easy installation and maintenance, and allows for individual solenoid valve testing without process interruption, ensuring continuous protection of the process during component servicing or replacement.
Implementation Method 1
solenoid operated valves
Data Source
AI summary
A voting solenoid system and method is configured to selectively apply fluid pressure above and below a threshold value, to a fluid node. The voting solenoid arrangement includes first and second solenoid valve pairs, each pair including first and second solenoid valves. The valve pairs are located in parallel fluid communication with a fluid pressure source, each of the first and second solenoid valves being alternately actuatable between energized and de-energized states. The solenoid arrangement is configured so that a change of state of the first and second valves of either of the valve pairs alternately applies fluid pressure above and below the threshold value, to the fluid node.