Research Projects: Electronics Design
Coaxial Power Systems Ltd are proud to be involved in the development and supply of specialist equipment for use in research projects, including electronics design.
Ultrasonic Flaw Detector
The long-range ultrasonic system uses guided ultrasonic waves, so called because the pipe acts as a wave-guide along which the sound travels. These waves are similar to the Lamb waves, which may be generated in plates. The frequencies used are much lower than those used for normal ultrasonic tests. Frequencies around 50kHz are used by the long-range ultrasonic system compared with around 5MHz for conventional thickness testing. The guided waves can travel many metres and therefore test large areas from a single point. Any changes in the thickness of the pipe, either on the inside or the outside, cause reflections that are detected by transducer wrapped around the pipe. Metal loss defects from corrosion/erosion inside the pipe or corrosion on the outside of the pipe can be detected. The system enables a trained operator to discriminate between metal loss and pipe features, welds in particular.
The main system components are:
- The low frequency flaw detector,
- The sensor tools for the pipe diameters to be tested,
- A ruggedised lap-top computer with specialised software for test, control and data analysis.
This is a 12 channel pulse-echo instrument, with all channels individually addressable. The long-range ultrasonic system 1 is designed for.
- Longitudinal operation
- Torsional operation
Basic Function
The long-range ultrasonic system detector is an intelligent remote unit operating under full control of the host computer. It operates on an umbilical cable, allowing the computer, peripherals and power supplies to be located in an appropriate environment. The umbilical is supplied up to 50m in length. All data transmission between the computer and the detector is digital.
The detector contains the transmitter circuitry to energise the ultrasonic transducers in the sensor tool and receivers to detect and amplify signals returned from the sensors. On-board signal processing allows pre-conditioning of signals prior to transmission to the host computer.
Dimensions
| Width | 300mm |
|---|---|
| Height | 200mm |
| Depth | 210mm |
| Weight | 7Kg |
Electronics Enclosure and casing design
Aluminium Alloy - IP65 rated against dust and moisture ingress
Environmental and Mechanical Robustness
The detector meets the requirements of European Standard ETS 300-019-2-7 for resistance to environmental factors and both vibration and impact loading.
Temperature Capabilities
| Storage | -30 to +85°C |
|---|---|
| Operating | 0 to +45°C |
Power Requirements
Power input to unit: 36V - 60V DC
Typical Current consumption 150mA @ 51V DC
Transmitter/Receiver design and manufacturing
a) Transmitter
| Channels | 12 |
|---|---|
| Output voltage | >250V peak to peak |
| Transmit Conversion resolution | 10 Bit |
| Output waveform | Tone burst |
| Pulse repetition frequency | 10Hz max |
| Bandwidth | 5 - 120kHz |
| Filters (low pass) | 100, 200, 300 and 400kHz (software selectable) |
b) Receiver
| Channels | 12 |
|---|---|
| Receive conversion resolution | 12 Bit |
| Frequency response | 7kHz to 300kHz |
| Gain | 20dB to 100dB adjustable in 1dB |
| Filters (low pass) | 25, 50, 100 and 150kHz (software selectable) |
| Filters (high pass) | 5, 10,25 and 50kHz (software selectable) |
Digital Performance
| Waveform Generation | D/A frequency 10MHz max., 10 bit accuracy |
|---|---|
| Received signal digitisation | A/D frequency 2MHz max., 12 bit accuracy |
| Signal averaging | Up to 4096 frames per sample |
Interface
| Protocol | "Arcnet" (LAN) |
|---|---|
| Data Rate | 5Mbits/Sec |
| Transmission line interface | EIA 485 |
| Operating System | Windows 95, 98, 2000, XP |
Power Supplies design
Mains power supply unit
| Input | 100-120V ~ 200V-240V~ 47-63 Hz, auto-ranging, |
|---|---|
| Output | 51V DC, 130 W continuous power. |
The power supply unit may be operated from 12V DC source (such as a vehicle battery), or with an optional 12V DC - 110V AC inverter.
Sensor tools
All sensor tools consist of rings of transducers. Individual elements are spaced equally around the pipe. The
transducers themselves are mounted in modules, which can be easily transferred between tools for different
pipe diameters. An inflatable collar is used to press the transducers into contact with the pipe. Note that
no coupling fluid is necessary in the frequency range used.
The number of modules per tool depends on the pipe size to be tested:
| Pipe diameter inches (nominal bore) |
Transducers Per ring |
Pipe diameter Inches (nominal bore) |
Transducers per ring |
|
|---|---|---|---|---|
| 2 | 12 | 24 | 60 | |
| 3 | 16 | 26 | 64 | |
| 4 | 20 | 28 | 68 | |
| 6 | 24 | 30 | 72 | |
| 8 | 28 | 32 | 76 | |
| 10 | 32 | 34 | 80 | |
| 12 | 36 | 36 | 84 | |
| 14 | 40 | 38 | 88 | |
| 16 | 44 | 40 | 92 | |
| 18 | 48 | 42 | 96 | |
| 20 | 52 | 44 | 100 | |
| 22 | 56 | 46 | 104 | |
| 48 | 108 |
All transducer rings may be divided into four quadrants as far as electrical connections are concerned, i.e. a separate signal may be collected from each quadrant of each ring, giving a maximum of 12 channels on reception.
Transducers
Piezoelectric, non-resonant, using shear mode oscillation
Transducer Mounting Mechanisms
All transducers are mounted in carriers (Modules). The modules are available in either longitudinal, or Torsional configuration. Transducer spacing for 30mm or 45mm operation in available depending on the frequency range selected.
Software design and Implementation
Function
The custom software is the principal user interface with the system. The software allows for a) test set up, b) selection of test conditions for any specific pipe size, c) management of data collection, and d) display and analysis of test data.
Mode of Operation
The long-range ultrasonic system system is capable of using either longitudinal or torsional guided waves when using the appropriate transducer module. This allows the different properties of both types of wave to be used, and to collect more information about the condition of the pipe under test.
Computer requirements (minimum)
- IBM compatible Lap-top with a Pentium II processor or later, operating at 1.7GHz or higher, running Windows™ 98, 2000 or XP
- Minimum RAM 512 Mbytes
- One PCMCIA interface card slot or one USB port
- One parallel port or one USB port
- A CD ROM drive for software installation
- Display resolution 1024 x 768 pixels or higher
