Valve Actuator Current Sensing for Stroke and Dead Zone Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Valve actuators in HVAC systems lack versatility due to the inability to interchangeably use valve controllers with different characteristic parameters, such as stroke lengths and dead zone lengths, limiting their adaptability across various types of valves.
Innovation Solution
A method and device for measuring valve characteristic parameters, including stroke length and dead zone length, using a motor-driven push rod with a current sensor to detect abrupt changes in DC drive current, allowing for accurate calculation and recording of these parameters, enabling the use of valve actuators with different types of valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If valve actuators are designed for specific valve types with fixed characteristic parameters, then the control precision for that specific valve type is improved, but the adaptability to different valve types deteriorates
Solution Approach 1:
The patent applies parameter changes by measuring the actual characteristic parameters (stroke length, dead zone length) of different valves and using these measured values to adjust the control parameters of the valve actuator. This allows the actuator to adapt to different valve types while maintaining precise control, resolving the contradiction between fixed design precision and adaptability.
2Adaptability or versatility
If mechanical means such as flaps are used to increase the versatility of valve actuators, then the adaptability to different valve types is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical adaptation mechanisms (flaps, mechanical adjusters) with an electrical measurement and control system. By using a current sensor to detect abrupt changes in drive current that indicate valve position limits, the system electronically determines valve characteristics without mechanical modification, reducing device complexity while maintaining versatility.
Solution Approach 2:
The patent introduces an intermediary measurement system that detects valve characteristic parameters through electrical signals (drive current changes) rather than direct mechanical interaction. This intermediary approach allows the valve actuator to adapt to different valve types through software/configuration adjustments rather than mechanical changes, simplifying the overall device structure.
3Measurement precision
If dedicated valve controllers are used for each valve type, then the control accuracy is improved, but the quantity of components increases
Solution Approach 1:
The patent implements universality by designing a single valve actuator controller that can control multiple types of valves. By measuring the characteristic parameters of each valve and storing these values, the controller automatically adapts to different valve types, eliminating the need for multiple dedicated controllers and reducing component quantity while maintaining control accuracy.
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
Enables the use of valve actuators with different types of valves by accurately measuring and calculating stroke and dead zone lengths, enhancing their versatility and adaptability.
Implementation Method 1
the motor is connected to a current sensor, which is adapted to measure a DC drive current flowing into the motor
Data Source
AI summary
Various embodiments of the teachings herein include a method for measuring valve characteristic parameters of a valve actuator. An example method includes: resetting the push rod to a top end position; driving the push rod; measuring the DC drive current in real time; recording a first position of the push rod at the start of a first abrupt change in the DC drive current when the first abrupt change in the DC drive current is detected and lasts for more than a first preset time period; continuing to drive the push rod and measure the DC drive current in real time; recording a second position of the push rod at the start of a second abrupt change; and calculating the stroke length of the valve based on the first position and the second position.