Ultrasonic Sensor Protective Membrane for Corrosive Environments
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Solution Overview
Problem
Ultrasonic level sensors face challenges when used in vessels containing corrosive or hazardous liquids, as these environments can damage the sensor's housing and transducer, leading to signal attenuation.
Innovation Solution
An ultrasonic distance sensor design that incorporates a protective element with a minimal attenuating effect on ultrasonic signals, specifically a membrane of resilient material that protects the transducer from corrosive environments while maintaining signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective element is provided to protect the ultrasonic transducer from corrosive or hazardous environment, then the reliability of the sensor is improved, but the transmitted ultrasonic signal is significantly attenuated
Solution Approach 1:
The patent employs a thin membrane made of elastomeric material as the protective element. This thin film structure provides corrosion protection while minimizing signal attenuation compared to thick rigid protective housings. The membrane's thinness allows ultrasonic signals to pass through with minimal energy loss.
Solution Approach 2:
The protective element is constructed from composite materials consisting of an elastomeric base material combined with corrosion-resistant particles or fibers. This composite structure provides both corrosion protection and acoustic transparency, allowing the material to resist chemical attack while maintaining ultrasonic signal transmission.
2Reliability
If the housing material is made resistant to corrosive materials, then the protection of the housing is improved, but the ultrasonic signal transmission is significantly attenuated
Solution Approach 1:
Instead of using thick corrosion-resistant housing materials that would block ultrasonic signals, the patent uses a thin elastomeric membrane as the protective element. This thin film provides the necessary corrosion protection while allowing ultrasonic waves to pass through with minimal attenuation.
Solution Approach 2:
The patent changes the thickness parameter of the protective material from thick (traditional housing) to thin (membrane), and changes the material properties from rigid to elastomeric. These parameter changes enable the protective element to provide corrosion resistance while maintaining acoustic transparency for ultrasonic signal transmission.
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 effectively protects the ultrasonic transducer from corrosive and hazardous environments while minimizing signal attenuation, ensuring accurate level monitoring with minimal interference.
Implementation Method 1
The ultrasonic transducer periodically transmits a burst of ultrasonic signals to the surface of the liquid or other material, the level of which is to be determined. The ultrasonic transducer then waits to receive echo signals of the burst of ultrasonic signals reflected from the surface of the contents of the vessel
Implementation Method 2
a protective element protecting the ultrasonic transducer from a corrosive or hazardous environment into which the signal from the ultrasonic transducer is to be transmitted
Data Source
AI summary
An ultrasonic level sensor (1) for monitoring the level of a liquid in a vessel comprises a main housing (3) having a lower part (5) and an upper part (6). An ultrasonic transducer (19) having an output face (25), through which ultrasonic signals are transmitted and received is housed in a sub-housing (39) located in an engagement recess (17) in the lower part (5). A communicating aperture (24) accommodates ultrasonic signals transmitted by the ultrasonic transducer (19) to and from the liquid surface, the level of which is to be monitored. The sub-housing (39) comprises a cylindrical side wall (40) extending upwardly from a protective element (35) for protecting the ultrasonic transducer (19). The protective element (35) comprises a circular disc of resilient material impermeable to corrosive gases and vapours in the vessel, the liquid level of which is being monitored, and comprises a central working portion (48) of diameter similar to that of the output face (25), and an outer peripheral portion (49) extending around the central working portion (48) of thickness greater than the thickness of the central working portion (48). The central working portion (48) is of constant thickness of approximately 0.35 mm and in its relaxed state is convex when viewed from the ultrasonic transducer (19), and is deformable into a planar configuration to abut and vibrate in unison with the output face (25) of the ultrasonic transducer (19) to minimise attenuation of the ultrasonic signals.