Systems and methods for flow estimation using differential pressure sensor across valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flow rate control systems in the HVAC industry rely on expensive flow sensors that require substantial pipe length for accurate measurements, making them impractical for small valves and increasing the overall size of control valve packages.
Innovation Solution
A system using differential pressure sensors to estimate flow rate through a valve, eliminating the need for flow sensors by employing a controller that determines an actuator position setpoint based on differential pressure measurements, with optional integration of multiple sensors and filtering techniques for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow rate sensor is used to measure flow rate accurately, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a differential pressure sensor as an intermediary device to indirectly measure flow rate through pressure differential across the valve, rather than directly measuring flow rate. This mediator approach allows accurate flow estimation without requiring complex flow rate sensors or substantial pipe length, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces the mechanical flow rate sensor system with a differential pressure sensing system combined with computational estimation. By using pressure measurements and algebraic relationships (Q = Cv * sqrt(ΔP)), the system achieves flow rate measurement without the mechanical complexity of traditional flow sensors, reducing both device complexity and package size while maintaining measurement precision
2Measurement precision
If a flow rate sensor with substantial pipe length is used, then measurement precision is improved, but the overall size of the control valve package increases
Solution Approach 1:
The differential pressure sensor serves as a compact intermediary that measures flow-related parameters without requiring substantial pipe length. By placing the sensor directly across the valve body, the system achieves accurate flow measurement in a compact configuration, eliminating the need for long straight pipe sections required by traditional flow sensors
3Measurement precision
If an expensive flow rate sensor is used, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent replaces expensive flow rate sensors with cheaper differential pressure sensors that can be manufactured at lower cost. While individual pressure sensors are less expensive than flow rate sensors, the system maintains measurement precision through proper sensor selection and computational estimation, significantly reducing overall system cost
Solution Approach 2:
The patent substitutes mechanical flow rate sensing with a combination of differential pressure sensing and computational estimation. This substitution eliminates the need for expensive flow rate sensors while maintaining measurement accuracy through the relationship Q = Cv * sqrt(ΔP), where Cv is the valve flow coefficient and ΔP is the differential pressure, thereby reducing manufacturing cost
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
This approach reduces costs and package size by using less expensive differential pressure sensors, while maintaining accurate flow control through the estimation of flow rates, improving the efficiency and compactness of control valve systems.
Implementation Method 1
a first differential pressure sensor configured to measure a first differential pressure across the valve
Data Source
AI summary
A system for controlling a flow rate of a fluid through a valve is provided. The system includes a valve and an actuator. An actuator drive device is driven by an actuator motor and is coupled to the valve for driving the valve between multiple positions. The system further includes a differential pressure sensor configured to measure a differential pressure across the valve and a controller that is communicably coupled with the differential pressure sensor and the motor. The controller is configured to receive a flow rate setpoint and the differential pressure measurement, determine an estimated flow rate based on the differential pressure measurement, determine an actuator position setpoint using the flow rate setpoint and the estimated flow rate, and operate the motor to drive the drive device to the actuator position setpoint.