Valve Actuator with Integrated Position Sensing for True Flow Feedback
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Solution Overview
Problem
Conventional fluid control systems in HVAC and industrial applications face inefficiencies due to mechanical linkages that introduce errors from backlash, hysteresis, and malfunctions, and fail to accurately measure fluid flow rates, leading to energy wastage and potential damage from false freeze detection.
Innovation Solution
A valve and actuator assembly that includes a valve actuator configured to measure and control fluid flow by sensing the position of the valve closure member, dynamic actuator force, and geometric properties, with a communications module for synchronization with building management systems and remote monitoring, and an anti-cavitation module to prevent fluid cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical linkages are used to connect the valve actuator and valve, then the valve stem position can be mechanically determined, but errors are introduced from backlash, movement hysteresis, or malfunction
Solution Approach 1:
The patent replaces the mechanical linkage system with an electronic sensing and communication system. A position sensor (such as a potentiometer, LVDT, or magnetic sensor) directly measures the valve stem position and sends an electrical signal to the controller, eliminating mechanical backlash, hysteresis, and linkage failures. This substitution of mechanical components with electronic components resolves the contradiction by improving reliability while reducing mechanical complexity.
2Device complexity
If the valve's closure member position is assumed to always follow the valve actuator valve stem position, then the feedback signal can be simplified, but error is introduced because the mechanical linkage may not be properly set up or operational
Solution Approach 1:
The patent implements a closed-loop feedback system where a position sensor directly measures the valve stem position and provides real-time feedback to the controller. This actual position feedback replaces the erroneous assumption-based feedback, allowing the system to accurately determine flow rate based on the true valve position rather than an assumed position, thereby improving measurement precision.
Solution Approach 2:
The patent replaces the mechanical assumption-based feedback system with an electronic sensing system that directly measures valve stem position. The position sensor converts mechanical position into an electrical signal that accurately reflects the actual valve position, eliminating errors from improper mechanical setup or linkage malfunction.
3Measurement precision
If flow meters are physically piped in series to measure fluid flow volume, then accurate flow measurement can be achieved, but the flow meters are located externally to the valve body increasing system complexity
Solution Approach 1:
The patent merges the flow measurement capability into the valve body itself by using the valve stem position sensor to determine flow rate. Instead of requiring a separate external flow meter piped in series, the valve assembly integrates position sensing and flow calculation functions, eliminating the need for external flow measurement equipment and reducing system configuration complexity.
Data Source
AI summary
A valve and actuator assembly that includes a valve configured to control a flow of liquid into a coil or heat exchanger. The valve and actuator assembly further includes a valve actuator configured to control opening and closing of the valve via positioning of a valve closure member. The valve actuator is further configured to provide both a maximum flow rate and a minimum flow rate of the liquid through the valve. In an embodiment, the valve actuator includes a valve closure member position sensor configured to determine the position of the valve closure member based on a flow rate of the liquid through the valve.