Actuator Lock-out Bracket for Valve Maintenance
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Solution Overview
Problem
Existing methods for locking out valves during maintenance are either too expensive, ineffective, difficult to install, or require excessive storage and tracking, and they do not adequately prevent fluid leakage from valves like butterfly valves, which can pose safety hazards during maintenance.
Innovation Solution
A lock-out bracket is designed to secure the position of a shaft extending through an actuator, featuring a flat base plate and a perpendicular lock-out tab with holes for a shackle to prevent movement of the valve, allowing for permanent installation without interrupting normal actuator operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air supply to actuators is removed to prevent valve opening during maintenance, then valve movement is restricted, but fluid leakage still occurs due to pressure building against the valve seat
Solution Approach 1:
The invention extracts the shaft from the actuator's control mechanism by removing it from the actuator while leaving the actuator body in place. This allows the shaft to be independently secured in a locked position using a lockout bracket, preventing the valve from opening due to pressure buildup while maintaining the actuator's ability to control the valve when the shaft is reinserted.
Solution Approach 2:
The control system is segmented into two independent parts: the actuator body that remains installed and the shaft that can be removed and independently secured. This segmentation allows the shaft to be locked in a fixed position using external locking mechanisms (lockout brackets and shackles) without affecting the actuator's mounting or requiring removal of the entire actuator assembly.
2Reliability
If expensive lockout devices are used to secure valves during maintenance, then valve position is reliably controlled, but cost and storage requirements increase
Solution Approach 1:
The lockout bracket system is designed to be self-contained and permanently mounted on the actuator, eliminating the need for separate storage of lockout devices. The bracket includes built-in holes and structural features that allow shackles to be directly attached without requiring additional components or storage space for maintenance of the lockout system itself.
Solution Approach 2:
The lockout bracket serves multiple functions: it provides structural support for the shaft, incorporates alignment holes for shackle attachment, and integrates with the actuator's existing limit switch bracket. This multi-functionality eliminates the need for separate storage of multiple different lockout devices for different scenarios.
3Reliability
If lockout devices are installed to secure valves during maintenance, then safety is improved, but installation complexity and time consumption increase
Solution Approach 1:
The lockout bracket is merged with the actuator's existing limit switch bracket structure, combining two functional elements into a single integrated component. This integration allows the lockout functionality to be added without requiring separate installation steps for mounting the bracket itself, as it utilizes the existing mounting infrastructure on the actuator.
Solution Approach 2:
The lockout bracket is designed with pre-positioned holes and structural features that align with the shaft and limit switch bracket before installation. This preliminary design of the bracket's geometry allows for quick alignment and attachment of the shackle without requiring complex measurement or adjustment procedures during the lockout process.
4Object-affected harmful factors
If shaft is removed from actuator to prevent valve opening, then valve cannot open during maintenance, but normal actuator operation is interrupted
Solution Approach 1:
The shaft is extracted from the actuator's control mechanism and secured independently using the lockout bracket system. This extraction allows the shaft to be locked in a fixed position without removing the actuator body from its mounting, enabling maintenance personnel to work on the valve while the actuator remains installed and ready for operation.
Solution Approach 2:
The system transitions from a static connection (shaft permanently attached to actuator) to a dynamic configuration where the shaft can be independently positioned and secured. The lockout bracket provides a reversible locking mechanism that allows the shaft to be fixed during maintenance and easily reconnected for normal operation, creating a flexible system that adapts to different operational states.
Data Source
AI summary
A lock-out bracket secures the position of a shaft extending through a pneumatic actuator, the shaft having a first end and a second end, the first end being operative for controlling a valve, the second end being coupled to a limit switch mounted on a limit switch bracket mounted to the actuator. The lock-out bracket includes a substantially flat base plate and a substantially flat lock-out tab substantially perpendicular to the base plate, the base plate defining an opening configured for matingly fitting over, receiving, and engaging the second end of the shaft. The lock-out tab defines a first hole adapted for alignment with a corresponding second hole defined on the limit switch bracket for facilitating the insertion of a lock shackle through the first hole and the second hole to secure the lock-out bracket relative to the actuator and prevent movement of the shaft and valve coupled to the shaft.