Flow Rate Measurement Device with Auxiliary Bypass Structure
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Solution Overview
Problem
Conventional flow rate measurement devices with bypass flow passage structures face challenges in maintaining measurement precision due to inhomogeneous flow speed distributions and the risk of liquid contamination, which can lead to inaccurate readings and damage to the detection element, especially in environments where dew condensation or water vapor is present.
Innovation Solution
The design includes a main flow pipe with an orifice and an auxiliary flow passage structure where the detection flow passage is positioned upstream and downstream relative to the auxiliary flow passages, with inclined bottom surfaces and side auxiliary flow passages to prevent liquid from entering the detection flow passage, ensuring the flow rate measurement device remains accurate even when tilted or used with liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a bypass flow passage structure is used to measure great flow rates, then the device can be downsized, but flow speed distribution becomes inhomogeneous and measurement precision decreases
Solution Approach 1:
A straight section is introduced as an intermediary component between the bypass flow passage and the detection flow passage. This straight section acts as a flow conditioning element that homogenizes the flow speed distribution before it reaches the detection area, thereby maintaining measurement precision while preserving the downsized structure enabled by the bypass configuration.
Solution Approach 2:
The flow passage structure is designed with different local characteristics: the bypass flow passage allows for compact routing, while the straight detection section provides a localized region of homogeneous flow. This local quality differentiation enables the device to achieve both small overall size and high measurement precision in the critical detection zone.
2Measurement precision
If the detection flow passage is positioned in the auxiliary flow passage structure, then flow speed can be measured, but liquid contamination can occur causing inaccurate readings and element damage
Solution Approach 1:
The inclined bottom surface design converts the harmful effect of gravity acting on liquid into a beneficial force that directs liquid away from the detection flow passage. By tilting the bottom surface downward toward the discharge side, liquid naturally flows away from the detection element rather than accumulating on it, thus protecting the element from contamination while maintaining the detection function.
Solution Approach 2:
The detection flow passage is positioned upstream relative to the auxiliary flow passage, creating a preliminary protective arrangement. This positioning ensures that even if liquid enters the auxiliary passage, it must travel against the flow direction or through the inclined surface away from the detection element, providing preliminary protection before liquid can potentially reach the detection area.
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 prevents liquid from contaminating the detection flow passage and detection element, maintaining measurement precision and reducing pressure loss, allowing for downsized devices capable of accurately measuring high flow rates with low power consumption.
Implementation Method 1
an orifice 49 for limiting a flow of gas in the main flow passage 43
Implementation Method 2
a flow rate detection element 47 for measuring a flow speed of the gas is provided in a detection flow passage 61
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An auxiliary flow passage is formed on the outer side of a main flow pipe 42 having a main flow passage 43. An orifice 49 for limiting a flow of a gas is provided in the main flow passage 43. The auxiliary flow passage includes a pair of introduction flow passages 56 communicating with the upstream side of the orifice 49, an upstream auxiliary flow passage 59 having both ends respectively connected to downstream ends of the introduction flow passages 56, a pair of discharge flow passages 57 communicating with the downstream side of the orifice 49, a downstream auxiliary flow passage 60 having both ends respectively connected to upstream ends of the discharge flow passages 57, and a detection flow passage 61 having both ends respectively connected to center of the second auxiliary flow passage 59 and center of the second auxiliary flow passage 60, the detection flow passage including a flow rate detection element 47. The upstream end of the detection flow passage 61 is positioned on the upstream side of the main flow passage 43 relative to the both ends of the upstream auxiliary flow passage 59, and the downstream end of the detection flow passage 61 is positioned on the downstream side of the main flow passage 43 relative to the both ends of the downstream auxiliary flow passage 60.