Valve Actuator Torque Shutdown Using Motor Speed Feedback
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Solution Overview
Problem
Existing valve opening and closing control systems are limited by wear and geometric changes, leading to inaccuracies in plug positioning and ineffective torque protection due to reliance on current measurement, which is complex and prone to fluctuations.
Innovation Solution
A precision opening and closing mechanism that uses motor rotation speed measurement to determine torque levels and implement shutdown, eliminating the need for current measurement and providing effective torque protection through a control unit connected to the valve actuator motor and mechanical reducer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If stroke limiters with limit switches are used to control valve opening and closing, then the valve movement can be limited to a fixed position, but the system cannot detect wear or geometric changes in the plug and seat, leading to positioning inaccuracy over time
Solution Approach 1:
The patent implements feedback by continuously monitoring motor current during operation. The control system compares actual current consumption against expected values for different valve positions and operational states. When wear or geometric changes cause deviations from expected current patterns, the system detects these changes and adjusts positioning accordingly, maintaining precision despite component degradation
Solution Approach 2:
The system dynamically changes operational parameters by monitoring motor current characteristics and adjusting control signals based on detected wear patterns. Instead of using fixed limit switch positions, the system adapts positioning parameters in real-time based on current consumption patterns, allowing it to compensate for geometric changes and wear in the valve components
2Reliability
If electronic torque limiters based on current measurement are used to protect valve actuators, then mechanical overstressing can be prevented, but the system becomes complex and prone to fluctuations that reduce protection effectiveness
Solution Approach 1:
The motor's own current measurement capability is utilized for torque protection without requiring external complex sensing systems. The control system processes the motor's inherent current signals to detect overload conditions, making the motor self-monitoring and eliminating the need for separate torque sensors or complex protection circuitry
Solution Approach 2:
The current measurement system serves multiple functions simultaneously: it monitors torque for protection purposes, determines valve position, and detects operational anomalies. This multi-functionality eliminates the need for separate dedicated torque sensing systems, reducing overall system complexity while maintaining reliable protection
Data Source
AI summary
Opening and closing mechanism which has a power supply (1), a rotation direction setter (2), a control unit (3), which is connected to the rotation direction setter (2), a valve actuator motor (5), which is connected to the control unit in which one of the connections is for sending a BREAK instruction from the control unit (3) to the motor (5), a signal which is sent when a shutdown occurs due to over-torque inferred from the motor rotation speed. This opening and closing mechanism is not limited by any wear of the plug, has no need to use measurement of the current drawn and establishes the torque level based on measurement of the motor rotation speed, the rotation speed corresponding to the nominal torque having been previously established.