Flow Control Valve with LVDT Float Displacement Measurement
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Solution Overview
Problem
Existing devices, such as rotameters and other flowrate measurement technologies, are inadequate for accurately measuring fluid flowrates at high pressures and low turn-down ratios, failing to provide precise measurements across a wide range of flow conditions.
Innovation Solution
A flow control valve assembly with a manifold system, including an inlet and outlet flow port, a float assembly, and a measuring device using a linear variable differential transformer (LVDT) to measure float displacement, which calculates flowrate by balancing forces and applying conservation of energy principles, allowing for accurate measurement of fluid flow even at high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rotameter is used to measure flowrate, then the device is simple and inexpensive, but it cannot be used at high pressures because it is typically made out of glass
Solution Approach 1:
The invention changes the material parameters of the rotameter from traditional glass to high-pressure resistant materials such as stainless steel or other suitable materials that can withstand high pressure environments while maintaining the rotameter's measurement functionality
Solution Approach 2:
The invention uses composite material construction for the rotameter, combining materials with different properties to achieve both high-pressure resistance and measurement accuracy, such as using stainless steel for the body and appropriate materials for the float and scale markings
2Reliability
If turbine meters or venturi tubes are used to measure flowrate, then the devices can handle high pressures, but they do not accurately measure flowrates at the low end with turn-down ratios below 20-to-1
Solution Approach 1:
The invention employs a variable area chamber that dynamically adjusts its cross-sectional area in response to flow rate changes, allowing the rotameter to maintain measurement accuracy across a wide range of flow rates including very low flow rates, achieving turn-down ratios greater than 100-to-1
Solution Approach 2:
The invention introduces a variable area dimension to the measurement system, where the cross-sectional area of the chamber changes with flow rate, providing an additional degree of freedom that enables accurate measurement at both high and low flow rates without compromising high-pressure capability
3Measurement precision
If a variable area chamber is introduced to extend float movement for low flow measurement, then low flow measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The variable area chamber serves multiple functions simultaneously: it enables low flow rate measurement by extending float movement, maintains high-pressure capability through its structural design, and provides a continuous measurement range across all flow rates, reducing the need for separate measurement systems
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
The solution enables precise measurement of fluid flowrates across a wide range of conditions, including high pressures and low turn-down ratios, by using a modular and adaptable design that effectively computes flowrates through the displacement of a float within a variable area chamber, ensuring accurate and reliable flow control.
Implementation Method 1
where Fd is the drag force
Implementation Method 2
where Fb is the buoyancy force
Implementation Method 3
by balancing forces and applying conservation of energy principles
Implementation Method 4
a measuring device which measures the displacement of the float
Data Source
AI summary
A flow control valve assembly has at least one manifold having an inlet flow port, an outlet flow port, and a flow channel provided therebetween, the flow channel having an inlet chamber, a variable area chamber and an outlet chamber, with fluid flowing from the inlet flow port to the inlet chamber, the variable area chamber and the outlet chamber, in that order, before exiting the outlet flow port. The flow control valve assembly also includes a float assembly extending inside the flow channel, the float assembly having a float that is limited for its movement inside the variable area chamber, a measuring device which measures the displacement of the float, and a connecting rod which connects the float to the measuring device. A bracket assembly is secured to the inlet chamber inside the flow channel, with the measuring device retained by the bracket assembly.