Pulsating Flow Meter Orifice Plate Low Rate Accuracy
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Solution Overview
Problem
Vortex flow meters face limitations in measuring low flow rates, especially for gases, due to sensor cutoff issues and noise interference, leading to inaccurate readings and reduced range, particularly at low flow rates or low densities.
Innovation Solution
A pulsating flow meter design incorporating a bluff body and an orifice plate within a housing, which imparts a pulsating flow pattern instead of vortex shedding, allowing for improved detection of pulsating frequency and flow rate determination, enhancing accuracy and noise-to-flow ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vortex flow meters are used for low flow rate measurement, then the device can operate in a wide flow range, but the measurement precision deteriorates at low flow rates due to sensor cutoff and noise interference
Solution Approach 1:
The invention changes the flow pattern parameter from vortex shedding to pulsating flow by introducing an orifice plate. This parameter change allows the flow meter to maintain measurement precision at low flow rates while preserving wide flow range capability, as the pulsating flow generates stronger pressure signals that are less susceptible to noise and sensor cutoff issues
Solution Approach 2:
The orifice plate acts as an intermediary element that transforms the flow characteristics. It converts the incoming flow into a pulsating flow pattern that produces measurable pressure variations, enabling accurate low flow rate measurements without the sensor cutoff problems that plague conventional vortex meters
2Device complexity
If conventional vortex meters are used, then the device structure is simple, but noise from pumps, valves, and compressors causes harmful interference leading to inaccurate readings
Solution Approach 1:
The invention converts the harmful noise interference into a beneficial measurement mechanism. By using an orifice plate to create pulsating flow, the system generates a strong periodic pressure signal that stands out above background noise. The pulsating frequency serves as a distinctive signature that can be easily differentiated from random process noise, transforming the noise problem into a measurement advantage
3Productivity
If the bluff body size is reduced to increase vortex frequency, then the measurement range extends to lower flow rates, but the pressure sensor signal strength decreases
Solution Approach 1:
The invention changes the flow pattern parameter from vortex shedding to pulsating flow through the orifice plate. This parameter change fundamentally alters the signal generation mechanism, producing stronger pressure variations that are less dependent on bluff body size. The pulsating flow creates more pronounced pressure signals even when the bluff body is small, maintaining signal strength while extending measurement range to lower flow rates
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 pulsating flow meter provides more accurate flow rate measurements at low flow rates and reduces noise-related errors, offering a higher signal response and longer streaming period compared to conventional vortex meters.
Implementation Method 1
the orifice plate is operable to impart a pulsating flow on process fluid as a result of passing through the orifice, wherein the pulsating flow has a pulsating frequency
Implementation Method 2
the bluff body is operable to impart a vortex flow pattern on process fluid that flows past the bluff body, wherein the vortex flow pattern has a vortex frequency
Data Source
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AI summary
A flow system based on pulsating mechanism that has better accuracy compared to conventional vortex meters due to the fact that the pulsations generated have increased signal response and lower frequency, both of which are favorable for a high accuracy measurement. Certain embodiments include a housing (44), a bluff body (20), an orifice plate (40), and means for detecting a pulsating frequency of pulsating flow and determining the fluid flow rate based on the detected pulsating frequency. In certain embodiments, the housing can include an outer shell (35), an inlet (36), and an outlet (38).