Discrete Valve Flow Conversion for Meterless Hydronic Control
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Solution Overview
Problem
In dynamic hydronic pumping systems, determining the flow rate of a valve without a flow meter is challenging, especially in systems where pressure control is managed using a control valve with a differential pressure sensor, as existing technologies require additional sensors or complex adaptive control methods.
Innovation Solution
A discrete valve flow rate converter that uses differential pressure and valve open position data, along with system characteristic calibration, to calculate the flow rate through a signal processor, employing a 3D discrete distribution function and numerical interpolations, allowing for accurate flow rate determination and control signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow meter is installed to measure valve flow rate, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the flow measurement function by using a mathematical model that replicates flow rate calculation based on differential pressure and valve position data. Instead of physically measuring flow with a flow meter, the system computes an equivalent flow value through numerical interpolation of the discrete distribution function g(Q, dP, d), achieving accurate flow rate determination without additional measurement hardware.
Solution Approach 2:
The patent introduces a signal processor as an intermediary that transforms readily available differential pressure sensor data and valve position data into flow rate information. This intermediary component processes the existing sensor signals through the discrete distribution function model, converting pressure and position measurements into meaningful flow rate values without requiring direct flow measurement.
2Measurement precision
If additional sensors are added to determine flow rate, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system makes existing sensors serve multiple functions. The differential pressure sensor, originally intended for pressure control, now also provides data for flow rate calculation. The valve position sensor serves both control and measurement purposes. By extracting flow rate information from the interaction of these existing sensors with the mathematical model, the system achieves flow measurement without adding dedicated flow sensing hardware.
3Measurement precision
If complex adaptive control methods are used, then flow rate determination accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent performs preliminary calibration to establish the discrete distribution function g(Q, dP, d) specific to each valve model before actual operation. This pre-computed model captures the valve's flow characteristics across different positions and pressure conditions. During operation, the system simply queries this pre-established model with current sensor readings, avoiding the need for real-time complex calculations or adaptive adjustments, thus maintaining simplicity while ensuring accuracy.
Data Source
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AI summary
A discrete valve flow rate converter is provided to obtain a system flow through a valve in a dynamic hydronic pumping system, e.g., based on signaling containing information about the valve's differential pressure and the valve's hydronic characteristics calibration data. The discrete valve flow rate converter resolves the valve system flow rate directly and accurately with the valve's open position and the corresponding valve differential pressure signals associated therewith. The discrete valve flow rate converter may be applied to all kinds of valves as long as their open position and differential pressure associated with is available, e.g., including implementations for control valve applications, e.g., where the valve open position is controlled automatically and accurately, as well as implementations either for pumping system pressure controls with the flow rate known, such as adaptive hydronic system pressure controls, or as an alternative to sensorless pump monitoring and control.