Pressure-Independent Flow Control Using Static Wave-Based Sensing
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Solution Overview
Problem
Existing flow control systems for pipe systems in buildings are limited by pressure variations, leading to inaccurate flow rate control and restricted applicability ranges, especially in non-residential buildings with multiple floors and varying pressures.
Innovation Solution
A flow control system using a flow sensor with a static measurement principle, such as ultrasonic or electromagnetic sensors, positioned outside the flow chamber, to measure actual flow and adjust an orifice independently of pressure, combined with a controller and an orifice adjusting system with an equal-percentage characteristic curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow control valves with adjustable orifices are used, then flow control is possible, but the control accuracy deteriorates due to pressure variations in the pipe system
Solution Approach 1:
The system continuously measures the actual medium flow using a flow sensor and compares it with the set flow value. Based on this feedback, the controller automatically adjusts the orifice position to compensate for pressure variations and maintain accurate flow control. This closed-loop feedback mechanism resolves the contradiction by making the system adaptive to changing pressure conditions while maintaining control accuracy.
Solution Approach 2:
The patent replaces traditional mechanical flow control mechanisms that rely on pressure-dependent characteristic curves with an electronic control system. The controller uses electronic signals from the flow sensor to actuate the orifice adjusting system, eliminating the need for mechanical calibration at specific pressure points and enabling accurate control across varying pressure conditions.
2Measurement precision
If flow sensors with moving parts (e.g., turbine sensors) are used to measure flow, then flow measurement is possible, but the measurement precision deteriorates at low flow rates and the device complexity increases
Solution Approach 1:
The patent employs flow sensors with static measurement principles such as ultrasonic or electromagnetic sensors that have no moving parts. These sensors measure flow by detecting changes in ultrasonic wave propagation time or electromagnetic field characteristics caused by the flowing medium. This substitution eliminates mechanical wear, reduces device complexity, and maintains high measurement precision across the entire flow range including low flow rates.
3Measurement precision
If the orifice adjusting system uses a linear characteristic curve, then the control system is simple, but the flow control precision deteriorates over wide pressure ranges
Solution Approach 1:
The patent implements an equal-percentage characteristic curve for the orifice adjusting system, where the relationship between orifice position and flow coefficient is non-linear. This dynamic characteristic allows the valve to provide finer control at low flows and coarser control at high flows, maintaining proportional control accuracy across wide pressure and flow ranges. The controller compensates for this non-linearity through its control algorithm, achieving high precision without requiring complex mechanical structures.
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
Achieves accurate and pressure-independent flow control over a wide range, minimizing calibration needs and maintaining precision across varying pressures, enabling efficient energy management and flow regulation.
Implementation Method 1
a flow sensor (1) for sensing an actual medium flow through the pipe part (6) and outputting an electrical signal indicative of the sensed actual medium flow, wherein the flow sensor (1) is provided outside the flow chamber (11) and has a static measurement principle based on a wave propagating in the medium
Implementation Method 2
A flow control system using a flow sensor with a static measurement principle, such as ultrasonic or electromagnetic sensors, positioned outside the flow chamber, to measure actual flow
Data Source
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AI summary
A pressure independent flow control system for use in a piping circuit of a central heating/cooling system and/or sanitary system, the flow control system being provided for controlling a flow of a liquid medium passing through a pipe part of the piping circuit of the central heating/cooling system and/or sanitary system in order to compensate for pressure variations in the piping circuit. The flow control system comprises a flow sensor, a controller and an orifice adjusting system. The flow sensor is provided in front of or behind the orifice adjusting system. The flow sensor has a static measurement principle based on a wave propagating in the medium.