Differential Pressure Flowmeter Temperature Stabilization
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Solution Overview
Problem
Differential pressure type flowmeters experience measurement errors due to rapid temperature changes in the fluid, which can cause inaccuracies in pressure detection and flow rate measurement, especially when the temperature of the fluid changes significantly.
Innovation Solution
The flowmeter design includes upstream and downstream pressure sensors with matching flow channel lengths and diameters, ensuring a ratio of 20 to 30 times, and a cooling structure with a fin design to maintain fluid temperature close to environmental temperature before reaching the sensors, thus minimizing measurement errors and ensuring fluid replaceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the temperature of fluid rapidly changes, then the fluid temperature reaches the pressure sensors quickly, but measurement errors are generated in the detection values due to temperature change
Solution Approach 1:
The patent applies preliminary action by designing flow channels with sufficient length (L/D ratio of 20-30 times) to allow the fluid temperature to stabilize before reaching the pressure sensors. This preliminary temperature stabilization prevents measurement errors caused by rapid temperature changes, ensuring accurate pressure detection even when the incoming fluid temperature changes quickly.
2Measurement precision
If the flow channel length is increased to allow temperature stabilization, then measurement accuracy improves, but the device size and fluid replacement time increase
Solution Approach 1:
The patent applies parameter changes by optimizing the flow channel dimensions, specifically setting the L/D ratio between 20-30 times. This optimized parameter range provides the minimum necessary length for temperature stabilization while preventing excessive channel length that would increase device size and fluid replacement time, achieving a balance between measurement accuracy and operational efficiency.
3Device complexity
If the flow channel length to diameter ratio is less than 20 times, then the device remains compact, but temperature stabilization is insufficient and measurement errors occur
Solution Approach 1:
The patent establishes the critical parameter threshold of L/D ratio being at least 20 times, which represents the minimum dimension required for effective temperature stabilization. This parameter setting ensures that the flow channel is sufficiently long to allow temperature equilibrium while maintaining reasonable device compactness, preventing measurement errors without excessive dimensional increase.
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 configuration effectively suppresses measurement errors caused by temperature changes and ensures accurate flow rate measurement while maintaining fluid replaceability, even when the fluid temperature rapidly changes from 25°C to 80°C.
Implementation Method 1
a first flow channel communicating with the main flow channel, and configured to guide the fluid on the upstream side of the orifice to the upstream pressure sensor; and a second flow channel communicating with the main flow channel, and configured to guide the fluid on the downstream side of the orifice to the downstream pressure sensor
Implementation Method 2
an upstream pressure sensor configured to detect pressure of fluid on an upstream side of the orifice; a downstream pressure sensor configured to detect pressure of fluid on a downstream side of the orifice
Data Source
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AI summary
There is provided a differential pressure type flowmeter 20 that includes an orifice provided in a main flow channel 13, a first pressure sensor 7 configured to detect pressure of fluid on an upstream side of the orifice, a second pressure sensor 8 configured to detect pressure of fluid on a downstream side of the orifice, a first pressure introduction flow channel 14 configured to guide the fluid on the upstream side of the orifice to the first pressure sensor 7, and a second pressure introduction flow channel 15 configured to guide the fluid on the downstream side of the orifice to the second pressure sensor 8, wherein a flow channel length L and a flow channel diameter D3 of the first pressure introduction flow channel 14 coincide with those of the second pressure introduction flow channel, respectively, and a ratio of the flow channel length L to the flow channel diameter D3 is not less than 20 times and not more than 30 times.