RU86015U1 - DEVICE FOR CONTACTLESS IDENTIFICATION OF THE PRESENCE AND LOCATION OF DEFECTS OF METAL PIPELINE - Google Patents

Abstract

A device for contactless detection of the presence and location of defects in a metal pipeline, comprising a system of magnetic field sensors, an analog-to-digital converter (ADC), a frequency generation and division unit, a control unit, a keyboard, an information display unit, an absolute geographical reference unit, a memory unit, an accelerometer unit , a unit for amplifying the signals of the magnetic field sensors, an analog subtraction unit and a power supply unit for the magnetic field sensors, while the output of the frequency generation and division unit is connected to the first ADC input, the first output of the control unit is connected to the input of the memory unit, the keyboard output is connected to the third input of the control unit, the output of the power supply of the magnetic field sensors is connected to the input of the magnetic field sensor system, the output of which is connected to the first input of the signal field amplification unit of the magnetic field sensors, the first output of the amplification block of the signals of the magnetic field sensors is connected to the second input of the ADC, the third input of which is connected to the output of the analog subtraction unit, to the input of which the second output of the unit is connected of signal signals, the ADC output is connected to the first input of the control unit, to the second input of which the output of the absolute geographic reference unit is connected, the output of the accelerator unit is connected to the fourth input of the control unit, and the second output of the control unit is connected to the input of the information display unit, characterized in that magnetoresistors are used as magnetic field sensors, while the power supply of the magnetic field sensors is made in the form of a stabilized DC source.

Description

The utility model relates to the field of metal inspection and can be used on trunk pipelines.

A device for non-contact magnetometric monitoring of the presence and location of a pipeline defect, comprising registration sensors connected to an analog-to-digital converter connected to a memory unit, a control unit connected via a recording control unit and an address unit to a memory unit, a crystal oscillator connected to a frequency divider, threshold unit connected to the light and sound signaling unit, automatic battery discharge indicator, RU 11608U1. The disadvantage of this device is its low sensitivity, which does not allow to register defects in pipelines of small diameters with a large depth of laying, as well as defects that cause slight deviations of the level of stress-strain state from background values.

A device is known for non-contact detection of the presence and location of defects in metal pipelines, comprising a system of sensors for detecting a magnetic field connected to an analog-to-digital converter, a crystal oscillator with a frequency divider, a control unit, a threshold level unit connected to an audio and light indication unit, an automatic discharge indicator batteries, information display unit, magnetic field gradient calculation unit, situational reference unit and absolute geographical reference unit and, a storage segment, a recording segment selection unit and a recording control unit, the control unit is connected to a situational reference unit, an absolute geographical reference unit, a recording segment selection unit and a recording control unit connected to a magnetic field gradient calculation unit, the recording segment selection unit is connected with a segment of a storage device connected via a magnetic field gradient calculation unit to an information display unit connected to a threshold level unit and automatic a battery discharge indicator, an analog-to-digital converter is connected to a magnetic field gradient calculation unit, RU2264617C2.

The disadvantage of this device is the low accuracy of the measurements, since when real measurements are carried out when moving the magnetic sensors in a constant magnetic field, large interference occurs, the compensation of which is absent.

A device is known for non-contact detection of the presence and location of defects in a metal pipeline, comprising a system of magnetic field sensors in the form of flux gates, an analog-to-digital converter (ADC), a frequency generation and division unit, a control unit, a keyboard, an information display unit, an absolute geographical reference unit, a unit memory, while the output of the frequency generation and division unit is connected to the first input of the ADC, the first output of the control unit is connected to the input of the memory unit, the keyboard output is connected to the third control unit input; the device also comprises an accelerometer unit, a magnetic field sensor signal amplification unit, an analog subtraction unit and a magnetic field sensor power supply in the form of an alternating current generator, the first output of the generator being connected to an input of the sensor system, the output of which is connected to the first input of the magnetic sensor signal amplifying unit field, the second input of which is connected to the second output of the generator, and to the first output of the amplification unit of the signals of the magnetic field sensors is connected to the second input of the ADC, to the third input of which the output of the analog subtraction unit is connected, to the input of which the second output of the sensor signal amplification unit is connected, the ADC output is connected to the first input of the control unit, the output of the absolute geographical reference unit is connected to the second input, the accelerometer unit output is connected to the fourth input of the control unit, and the second the output of the control unit is connected to the input of the information display unit, RU 55989 U1.

The device of patent RU 55989 improves the accuracy of measurements of the device by providing compensation for interference arising from the movement of magnetic sensors in a constant magnetic field.

This technical solution was made as a prototype of this utility model.

However, this device has certain disadvantages.

Flux probes used as magnetic field sensors require AC generators for their power supply (excitation); the “ordinary low-frequency alternator” used in the prototype gives a sinusoidal voltage with higher-order harmonics at the output. This causes serious errors and even errors in the identification and location of defects in a metal pipeline. In addition, the flux gates used in the prototype as magnetic field sensors, due to their own inductance and the resulting non-linearity of the frequency response, are very sensitive to interference in the form of extraneous electromagnetic fields, which also negatively affects the accuracy of the device. It should also be noted that in the prototype device, the signal from the generator output is supplied directly to the second input of the sensor signal amplification unit, and the signal from the sensor system is supplied to the first input of this block, and these signals are compared in the amplification unit.

The difference in these signals is due to the presence of fluctuations in the magnetic field caused by defects in the pipeline. The gain block amplifies the difference signal. This requires a high gain of this unit, which leads to an increase in the sensitivity of the device to interference (noise).

The objective of this utility model is to increase the accuracy of identifying and locating defects in a metal pipeline.

According to a utility model, a device for non-contact detection of the presence and location of defects in a metal pipeline, comprising a system of magnetic field sensors, an analog-to-digital converter (ADC), a frequency generation and division unit, a control unit, a keyboard, an information display unit, an absolute geographical reference unit, a unit memory, accelerometer unit, magnetic field sensor signal amplification unit, analog subtraction unit and magnetic field sensor power supply, while the output of the generation and division unit frequency is connected to the first input of the ADC, the first output of the control unit is connected to the input of the memory unit, the keyboard output is connected to the third input of the control unit, the output of the power supply of the magnetic field sensors is connected to the input of the magnetic field sensor system, the output of which is connected to the first input of the sensor signal amplification unit of the magnetic field, the second input of the ADC is connected to the first output of the amplification block of the signals of the magnetic field sensors, the output of the analog subtraction unit is connected to the third input of which is connected to the input the second output of the sensor signal amplification unit is switched on, the ADC output is connected to the first input of the control unit, the output of the absolute geographic reference unit is connected to the second input of it, the output of the accelerator unit is connected to the fourth input of the control unit, and the second output of the control unit is connected to the input of the information display unit, magnetoresistors are used as magnetic field sensors, while the power supply of the magnetic field sensors is made in the form of a stabilized DC source.

The essence of the utility model is illustrated in the drawing, which shows a block diagram of the device.

The device includes a system 1 of magnetic field sensors, which are used magnetoresistors. In a specific example, this is a system of four magnetoresistors of the type NMS 1053 manufactured by HONEYWELL; in the drawing, for simplification, they are shown as a single system 1. The analog-to-digital converter (ADC) 2 is assembled on the EKZHB.467605.009 chip. Block 3 of the generation and division of the frequency is a combination of a crystal oscillator and a frequency divider, combined in a chip KR 1024. The control unit 4 is assembled on the basis of KNPS.467441.001. Keyboard 5 is a NIKO. 467126.061 control panel. The information display unit 6 is an LM 42248 B6-WNY matrix liquid crystal display. Block 7 absolute geographic reference is a GPS receiver 4600 LS. The memory unit 8 is assembled on the basis of FLASH-memory of the type KNPS.467669.001. Block 9 is a combination of two horizontal accelerometers based on ADXL 311 and AD 8642 microchips. Block 10 is a standard amplifier for amplifying the signals of magnetic field sensors. Block 11 power subtraction of signals collected on the chip OR 297.

The power supply unit 12 of the magnetic field sensors is a stabilized direct current source containing a 12 V battery with a current stabilization circuit performed in this example on an ORA 369 chip from TEXAS Instruments.

The output of the unit 3 for generating and dividing the frequency is connected to the first input of the ADC 2, the first output of the control unit 4 is connected to the input of the memory unit 8.

The output of the keyboard 5 is connected to the third input of the unit 4. The output of the power supply unit 12 of the magnetic field sensors is connected to the input of the system 1 of the magnetic field sensors. The output of the system 1 is connected to the first input of the signal amplification unit 10 of the magnetic field sensors.

The first output of block 10 is connected to the second input of the ADC 2, the second output of block 10 is connected to the input of the analog subtraction unit 11, the output of which is connected to the third input of the ADC 2. The output of the ADC 2 is connected to the first input of the control unit 4, the second input of which is connected to the output of the block 7 absolute geographic reference. The output of unit 9 of the accelerometers is connected to the fourth input of unit 4, the second output of unit 4 is connected to the input of information display unit 6.

The device operates as follows.

System 1 sensors magnetoresistors captures the magnetic field of the main pipeline. The stabilized DC source 12 provides power to all four magnetoresistors. The output analog signals of the sensors are fed to the second input of the ADC 2 and to the input of the block 11 analog subtraction. From the output of block 11, where the analogous subtraction of the magnetic field components of the same name located at different points of the pipeline is performed, the differences obtained are fed to the input of the ADC 2. A crystal oscillator 3 with a frequency divider provides the ADC with a selected quantization frequency of the sensor signals of 30 Hz.

The signals from block 7 of the absolute geographic reference, from block 9 of the accelerometers, from the ADC 2 are sent to the control unit 4 with the keyboard 5. Recording of the recorded signals together with the service information is carried out in the memory unit 8. Block 6 displays information about the presence or absence of GPS satellites, the angles of deviation of the sensor system from the vertical in two directions; at the choice and request of the operator, the monitor displays the results of registration of the magnetic field components.

The two accelerometers making up block 9 fix and reflect on the screen of block 6 the angles of deviation of the sensor system 1 from the vertical in real time. Due to this, in the process of work, it becomes possible to immediately correct the position of the sensors of the system 1 and transfer them to a position with some minimally achievable deviation of their axes from the verticals in two planes. Due to this, the components of the magnetic field of the pipeline and their gradients are measured with higher accuracy. In addition, information on the indicated minimum attainable deviations serves as the basis for making corrections in the right place (which is provided by block 7) at the stage of processing the results, which allows for almost complete compensation for the influence of interference arising from the movement of magnetic sensors in the magnetic field of the pipeline along his tracks.

After making corrections, in the memory unit 8, the background values of the components of the magnetic field of the pipeline and the gradients of this field are fixed, and then, based on classical statistical processing, the anomalous values of the integral field parameters corresponding to the presence of pipeline defects and their location are selected.

Since magnetic sensors in the form of magnetoresistors do not have their own inductance and have a purely active resistance, they have a practically linear characteristic and are slightly sensitive to the effects of extraneous electromagnetic fields, which in this case can be easily filtered by standard means, in particular, RC filters. In addition, since the use of magnetoresistors as sensors eliminates the need for an excitation generator, interference in the form of higher-order harmonics present in the sinusoidal voltage generated by the excitation generator and, accordingly, the errors and errors due to them in identifying and determining the location of defects in a metal pipeline, are also eliminated.

The following is also important. Magnetic field sensors in the form of magnetoresistors produce a voltage directly proportional to the magnetic field generated by a metal pipe, the value of which changes if there is a pipe defect. In this case, in the amplification unit 10, the signals of the magnetic field sensors are directly amplified, and not the difference signal. Due to this, a high gain of the block 10 is not required, which provides a significant reduction in the sensitivity of the device to interference.

Thus, the implementation of the features of the utility model reduces both the intrinsic interference emitted by the device and its sensitivity to external interference, which improves the accuracy of detection and location of defects in a metal pipeline.

Claims (1)

A device for contactless detection of the presence and location of defects in a metal pipeline, comprising a system of magnetic field sensors, an analog-to-digital converter (ADC), a frequency generation and division unit, a control unit, a keyboard, an information display unit, an absolute geographical reference unit, a memory unit, an accelerometer unit , a unit for amplifying the signals of the magnetic field sensors, an analog subtraction unit and a power supply unit for the magnetic field sensors, while the output of the frequency generation and division unit is connected to the first ADC input, the first output of the control unit is connected to the input of the memory unit, the keyboard output is connected to the third input of the control unit, the output of the power supply of the magnetic field sensors is connected to the input of the magnetic field sensor system, the output of which is connected to the first input of the signal field amplification unit of the magnetic field sensors, the second output of the ADC is connected to the first output of the amplification block of the signals of the magnetic field sensors, the output of the analog subtraction unit is connected to the third input of which the second output of the unit is connected to the input of signal signals, the ADC output is connected to the first input of the control unit, to the second input of which the output of the absolute geographic reference unit is connected, the output of the accelerator unit is connected to the fourth input of the control unit, and the second output of the control unit is connected to the input of the information display unit, characterized in that magnetoresistors are used as magnetic field sensors, while the power supply of the magnetic field sensors is made in the form of a stabilized DC source.