EMAT Array Coil Winding for Guided Wave Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional guided wave testing using piezo-electric and magneto-strictive transducers faces challenges with mechanical coupling issues and environmental sensitivity, while electromagnetic acoustic transducers (EMATs) have poor sensitivity and are hindered by high power requirements and electromagnetic cross-talk, limiting their use in hazardous environments and causing blind spots.
Innovation Solution
A linear array of receiver and transmitter EMATs with specific coil winding directions and connections, allowing for non-contact electro-magnetic coupling, directional guided wave excitation, and reduced breakthrough signals through differential driving and symmetrical coil arrangements, enabling effective signal reception with closely located transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezo-electric or magneto-strictive transducers are used for guided wave testing, then high sensitivity and strong signals are achieved, but mechanical coupling issues and environmental sensitivity cause changes in transduction sensitivity
Solution Approach 1:
The patent replaces mechanical coupling transducers (piezo-electric and magneto-strictive) with electromagnetic acoustic transducers (EMATs) that use non-contact electromagnetic coupling. This substitution eliminates the mechanical bonding issues and environmental sensitivity problems while maintaining guided wave excitation and detection capabilities
2Reliability
If EMATs are used for non-contact testing, then mechanical coupling issues are reduced and coating penetration is improved, but transduction sensitivity becomes poor
Solution Approach 1:
The patent combines multiple EMAT transducers into an array configuration where multiple transmitter EMATs and multiple receiver EMATs work together. The signals from multiple receiver EMATs are processed to reconstruct the transmitted signal, thereby improving overall transduction sensitivity while maintaining the non-contact advantages of EMATs
3Measurement precision
If high power EMATs are used to produce usable signals, then signal strength is improved, but intrinsic safety concerns restrict use in hazardous environments
Solution Approach 1:
The patent combines multiple low-power EMAT transducers into an array where their signals are aggregated through processing. This approach achieves usable signal strength without requiring high power from individual transducers, thereby maintaining intrinsic safety for use in hazardous environments
4Measurement precision
If high gain amplifiers are used to receive weak EMAT signals, then signal reception is improved, but electro-magnetic cross talk and settling times create blind spots
Solution Approach 1:
The patent segments the transducer system into spatially separated transmitter and receiver EMAT arrays. By distributing multiple transducers along the pipe and using selective signal processing, the system reduces electro-magnetic cross talk and settling time issues while maintaining signal reception capability
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 enhances sensitivity and reduces electromagnetic interference, allowing for accurate guided wave testing with low axial separation along pipes, effectively detecting defects while minimizing environmental and operational limitations.
Implementation Method 1
electromagnetic acoustic transducers (EMATs) have a receiver coil and serving to convert vibrations in said test object into received electrical signals in said receiver coil; and at least one linear array of transmitter electromagnetic acoustic transducers... each of said transmitter electromagnetic acoustic transducers having a transmitter coil and serving to convert driving electrical signals in said transmitter coil into vibrations in said test object
Implementation Method 2
receiver electromagnetic acoustic transducers... having a receiver coil and serving to convert vibrations in said test object into received electrical signals in said receiver coil
Data Source
AI summary
An apparatus for guided wave testing of a test object comprises a linear array of receiver electromagnetic acoustic transducers (EMATs), and at least one linear array of transmitter EMATs disposed substantially parallel to the linear array of receiver EMATs and configured to launch guided waves in said test object in a direction substantially perpendicular to the at least one linear array of transmitter EMATs. Either (i) transmitter coils of the at least one linear array of transmitter EMATs have a common winding direction, receiver coils of adjacent receiver EMATs have alternating winding directions, and receiver coils of at least two adjacent receiver EMATs are connected in series, or (ii) transmitter coils of the transmitter EMATs have alternating winding directions, receiver coils of adjacent receiver EMATs have a common winding direction, and receiver coils of at least two adjacent receiver EMATs are connected in series.