Ultrasonic Flowmeter Integral Insert Molding for Accuracy
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Solution Overview
Problem
Ultrasonic flowmeters face challenges in accurately measuring micro flow rates of slurry fluids due to deposition of slurry at bent pipe portions, variations in mounting of transmitting bodies, and difficulties in fabricating small-diameter measurement pipes with smooth inner surfaces, leading to reduced measurement accuracy and signal strength.
Innovation Solution
The method involves fabricating measurement pipes and transmitting bodies integrally using insert molding, eliminating the need for adhesives and allowing for precise positioning of transmitting bodies, which reduces surface roughness and prevents bubble adhesion, thereby improving measurement accuracy and signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transmitting bodies are mounted on measurement pipe using adhesives or welding, then ultrasonic flowmeter can be assembled, but positions of transmitting bodies vary depending on operator proficiency causing deterioration of measurement accuracy
Solution Approach 1:
The transmitting bodies and measurement pipe are merged into a single integral structure formed by injection molding, eliminating the need for separate assembly steps involving adhesives or welding. This ensures consistent positioning of transmitting bodies relative to the measurement pipe, improving measurement accuracy while maintaining ease of manufacture through automated molding processes.
2Measurement precision
If measurement pipe and transmitting bodies are formed integrally by injection molding, then assembly variation is eliminated, but draft in inner diameter causes non-constant flow velocity
Solution Approach 1:
The flow passage is segmented into two distinct zones: a measurement section with constant inner diameter for accurate flow velocity measurement, and a transmitting body mounting section with draft angle for ease of mold removal. This segmentation allows each zone to optimize its geometric characteristics independently, resolving the conflict between positioning accuracy and manufacturing feasibility.
3Ease of manufacture
If bent portions are formed on measurement pipe ends, then flow passages can be connected, but slurry deposits on bent portions hindering ultrasonic vibration propagation
Solution Approach 1:
The bent portions that cause slurry deposition are extracted and relocated to the transmitting body mounting sections, separating the flow passage connection function from the measurement section. The measurement pipe ends are left straight to prevent slurry accumulation, while bends are incorporated into the transmitting body housing where they cannot interfere with ultrasonic signal transmission through the fluid.
4Ease of manufacture
If small-diameter measurement pipe is fabricated by cutting work, then transmitting bodies can be integrated, but microasperity on inner surface causes bubble adhesion reducing signal strength
Solution Approach 1:
The measurement pipe is preliminarily formed with a smooth inner surface through injection molding before transmitting bodies are integrated. This preliminary action of creating a bubble-resistant surface prevents microasperity formation that would otherwise occur with cutting operations, thereby maintaining strong ultrasonic signal transmission while enabling transmitting body integration.
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 approach enables high-accuracy measurement of micro flow rates without the need for adhesives, reduces operator dependency, and facilitates the production of small-diameter measurement pipes with reduced surface roughness, enhancing the reliability and precision of ultrasonic flowmeters.
Implementation Method 1
an ultrasonic transceiver, which propagates an ultrasonic vibration through a fluid
Implementation Method 2
measures a flow velocity or flow rate of the fluid from a difference between ultrasonic wave propagation time from an upstream side of the flow and ultrasonic wave propagation time from a downstream side of the flow
Data Source
AI summary
An ultrasonic flowmeter includes a measurement pipe through which a fluid flows, and two ultrasonic transceivers provided on outer side portions of the measurement pipe so as to be spaced apart from each other in an axis direction. In the method of producing the ultrasonic flowmeter, fabricating the measurement pipe in advance is fabricated, and then is set in a mold as an insert. Two transmitting bodies are formed by insert molding on the outer side portions of the measurement pipe so as to be spaced apart from each other in the axis direction, so that the two transmitting bodies are integral with the measurement pipe. The two ultrasonic transceivers are mounted on the two transmitting bodies, respectively.