CN217717610U - Pipeline nondestructive test system in portable heat preservation - Google Patents

Abstract

The utility model discloses a movable thermal insulation inner pipeline nondestructive testing system, which comprises a microprocessor and a data acquisition system for nondestructively acquiring pipeline condition data in the thermal insulation layer, wherein the microprocessor outputs signals to control the work of the data acquisition system and processes the data acquired by the data acquisition system; the data acquisition system comprises a nondestructive testing probe and a movable base for mounting the nondestructive testing probe; the movable base comprises an opening bracket surrounding the heat-insulating layer and a plurality of flexibly connected supports; the bottom of each support is provided with a pulley and a lantern ring, the lantern ring is sleeved on the opening support, and the height of the pulley is higher than that of the lantern ring; the opening end of the opening bracket is in clearance fit with the surface of the heat-insulating layer; the nondestructive testing probes are positioned at the top of the support and distributed in an array manner, generate a pulse magnetic field, enable the pipeline in the insulating layer to generate eddy currents under the action of the pulse magnetic field, induce the magnetic field generated by the eddy currents and output testing signals. The utility model discloses thereby can follow pipeline surface and slide and survey in succession.

Description

Pipeline nondestructive test system in portable heat preservation

Technical Field

The utility model relates to a pipeline situation detection technical field in the heat preservation, in particular to portable pipeline nondestructive test system in heat preservation.

Background

Corrosion in insulation (CUI) refers to a corrosion phenomenon that occurs on the outer surface of a pipe or equipment that houses insulation. Statistically, over 60% of pipeline failures in the petrochemical industry are caused by CUI, and the economic loss caused by a series of serious problems such as dangerous product leakage, abnormal operation of equipment and even casualties caused by the faults of equipment and pipelines caused by CUI is up to billions of dollars each year. Most of equipment and pipelines in the petroleum industry are made of carbon steel and stainless steel, an external protective layer and an insulating layer are damaged due to installation, operation, performance and external factors, a local corrosion environment can be formed between an insulating material and the pipelines, media such as air, water and the like are in contact with metal pipelines to generate oxidation reaction and electrochemical reaction to cause CUI, and the corrosion in the insulating layer is more serious on the surfaces of the pipelines or the equipment which are not coated or are in a corrosive industrial atmosphere.

In the production process of offshore oil and gas fields, pipeline corrosion in the heat-insulating layer is always a common problem because the pressure container and the pipeline on the platform are in a high-salt and high-humidity marine environment for a long time. The corrosion of the pipeline is difficult to be found through the outer surface of the heat-insulating layer, and the conventional detection means needs to remove the heat-insulating layer outside the pipeline, so that the operation and maintenance cost is increased. Currently, nondestructive testing techniques in thermal insulation layers are also increasingly used. There are many non-destructive testing techniques suitable for corrosion in insulation, but most of these techniques can only achieve effective testing when significant fluid leakage occurs. There is a pressing need in the industry for techniques that allow detection without removing the insulation cover. Common nondestructive testing techniques suitable for corrosion in the insulating layer include an ultrasonic testing (ultrasonic ranging) method and a mechanical testing method. The ultrasonic ranging method has the advantages of accurate measurement, no contact, low cost, only need of measuring one side of the measured component and the like. However, the measurement accuracy of ultrasonic waves is affected due to the fact that accumulated water, dirt, impurities and the like often appear in the pipeline, misdetection and misreporting are prone to occur, the inspection is limited to a small range, and each different material needs to be calibrated. The mechanical detection method as a traditional mechanical deformation detector can only detect deformation damage of the inner pipe wall, but cannot detect other parts such as the outer pipe wall, and has the defects of damage to the detected inner pipe wall, data drift caused by probe abrasion, over-high speed or data distortion caused by impact during detection.

As a new type of nondestructive testing technology, pulsed eddy current testing technology is gradually being widely studied and applied. The patent 'method and device for detecting corrosion of a component with a magnetic conductive material protective layer' sets a pulse eddy current detector on a protective layer of a selected reference area and a to-be-detected area on the surface of a to-be-detected component, and judges the corrosion condition by using the difference of induced voltage attenuation curves of the two areas. The document 'pulsed eddy current wall thickness detection penetrating through an insulating layer and an anticorrosive layer' utilizes a pulsed eddy current heavy current technology to penetrate through an isolation layer for detection, the signal penetration capability is strong, but the detected average thickness is within a certain range, and the detection cannot be realized in a region with limited sensor activity, so that the integral measurement performance is influenced.

Therefore, it is urgently needed to develop a method/system for accurately detecting the corrosion condition in the heat-insulating layer of the pipeline carrying the complex fluid in the well and the sealed space in the heat-insulating layer.

Disclosure of Invention

The utility model provides a portable thermal insulation layer inner pipeline nondestructive test system for solving the technical problem existing in the prior art.

The utility model discloses a technical scheme who takes for solving the technical problem that exists among the well-known technique is: a movable nondestructive testing system for pipelines in an insulating layer comprises a microprocessor and a data acquisition system for nondestructively acquiring pipeline condition data in the insulating layer, wherein the microprocessor outputs signals to control the work of the data acquisition system and processes the data acquired by the data acquisition system; the data acquisition system comprises a nondestructive testing probe and a movable base for mounting the nondestructive testing probe; the movable base comprises an opening bracket and a plurality of flexibly connected supports, wherein the opening bracket surrounds the outside of the heat preservation layer; a pulley and a lantern ring are arranged at the bottom of each support, the lantern ring is sleeved on the opening support, and the height of the pulley is higher than that of the lantern ring; the opening end of the opening bracket is in clearance fit with the surface of the insulating layer; the nondestructive testing probes are positioned at the top of the support and distributed in an array manner, generate a pulse magnetic field, enable the pipeline in the insulating layer to generate eddy currents under the action of the pulse magnetic field, induce the magnetic field generated by the eddy currents and output testing signals.

Furthermore, the nondestructive testing probe comprises an electromagnetic transmitting coil and an electromagnetic receiving coil which are coaxially wound; the data acquisition system also comprises a pulse signal generator and an analog-to-digital converter; the microprocessor controls the pulse signal generator to output a pulse signal to the electromagnetic transmitting coil; the electromagnetic transmitting coil generates a pulse magnetic field, the electromagnetic receiving coil induces the magnetic field generated by the eddy current and outputs a detection signal, the analog-to-digital converter converts an analog signal detected by the electromagnetic receiving coil into a digital signal and outputs the digital signal to the microprocessor, and the microprocessor processes the digital signal.

Furthermore, the pulse signal generator comprises two MOS tube drivers and four field effect tubes, and the four field effect tubes form an H-bridge circuit; the high and low level output ends of each MOS tube driver respectively correspond to the control ends of the upper and lower arm field effect tubes on one side of the H-bridge circuit; the microprocessor simultaneously generates two pulse width modulation signals A and two pulse width modulation signals B; two paths of pulse width modulation signals A are respectively input to high-end input ends of two MOS tube drivers; two pulse width modulation signals B are respectively input to the low-end input ends of the two MOS tube drivers; the output end of the H-bridge circuit is connected with the electromagnetic transmitting coil. The duty cycles of the pulse width modulated signal a and the pulse width modulated signal B may be equal.

Furthermore, the data acquisition system also comprises a filter amplifier; the filter amplifier is connected between the output end of the electromagnetic receiving coil and the input end of the analog-to-digital converter.

Furthermore, the data acquisition system also comprises a driving device for driving the opening bracket to move along the surface of the heat preservation layer; the driving device comprises an axial moving motor arranged on the open bracket, and the open bracket moves axially along the pipeline when the axial moving motor rotates.

Further, the driving device also comprises a circumferential moving motor arranged on the opening bracket, and the opening bracket moves along the circumferential direction of the pipeline when the circumferential moving motor rotates.

Further, the open end of the open bracket is a telescopic open end, and the opening angle of the open end is 120-180 degrees.

Furthermore, the top of the open bracket is a polygon with equal side length which is more than or equal to the width of the support; each side of the polygon is sleeved with a support.

Furthermore, the nondestructive testing probes are distributed along the circumferential direction of the surface of the insulating layer at equal intervals.

Furthermore, the bottom of each support is provided with two pulleys and four lantern rings; the two pulleys are positioned on the central line of the bottom of the support in the front-back direction; the four lantern rings are symmetrically arranged along the central line of the bottom of the base in the front-back direction and the left-right direction.

The utility model has the advantages and positive effects that:

(1) At the detection pipeline in-process, be arranged in ground usually by the detection pipeline, in order to improve the utility model discloses the work efficiency of detecting system detector, the utility model discloses need to design the slip detection structure that can carry on the tractor for thereby the detector can be when guaranteeing to stabilize to survey, under mobile drive device's drive, slides along pipeline surface and surveys in succession.

(2) In practical application, aiming at the conditions that the pipe diameters of the sleeves are different, the thicknesses of the applied heat-insulating layers are different and the like, the pipeline detection under the pipeline heat-insulating layer has higher adaptability requirements. To this problem, the utility model discloses need to design adjustable many probe structures to adjust suitable detection structure at any time according to the site conditions, accomplish the detection to corroding the pipeline under the different pipe diameter heat preservation.

(3) The pipeline surface that has the heat preservation is not smooth unimpeded usually, in order to accomplish the detection work smoothly high-efficiently, the utility model discloses add and keep away the barrier function to guarantee that the detector can bypass various obstacles on the heat preservation in a flexible way.

Drawings

Fig. 1 is a schematic structural view of the movable nondestructive testing system for pipelines in heat-insulating layers of the present invention when installed on pipelines.

Fig. 2 is the utility model discloses a structural schematic diagram of pipe nondestructive test system under removal base development condition in portable heat preservation.

Fig. 3 is the utility model discloses a section schematic diagram of when pipeline nondestructive test system installs on the pipeline in portable heat preservation.

Fig. 4 is a schematic diagram of a flexible connection structure of a support of the mobile base.

Fig. 5 is a bottom view of the holder.

Fig. 6 is a top view of the pedestal.

Fig. 7 is the utility model discloses a portable pipe nondestructive test system's in heat preservation electrical schematic diagram.

FIG. 8 is a schematic view of the structure of the nondestructive testing probe.

In the figure: 1. a traction device; 2. a heat-insulating layer; 3. a detection cartridge; 4. a movable base; 5. a hub; 6. a battery; 7. an upper computer; 8. a microprocessor; 9. a communication module; 10. a connecting belt; 11. a support; 12. an open bracket; 13. a pipeline; 14. an obstacle avoidance opening; 15. a pulley; 16. a collar; 17. a threaded bore.

Detailed Description

For further understanding of the contents, features and effects of the present invention, the following embodiments are listed and will be described in detail with reference to the accompanying drawings:

referring to fig. 1 to 8, a mobile nondestructive testing system for an inner pipe 13 of an insulating layer comprises a microprocessor 8 and a data acquisition system for nondestructively acquiring status data of the inner pipe 13 of the insulating layer 2, wherein the microprocessor 8 outputs a signal to control the work of the data acquisition system and processes the data acquired by the data acquisition system; the data acquisition system comprises a nondestructive testing probe and a movable base 4 for mounting the nondestructive testing probe; the movable base 4 comprises an opening bracket 12 and a plurality of flexibly connected supports 11 which surround the heat insulation layer 2; a pulley 15 and a lantern ring 16 are arranged at the bottom of each support 11, the lantern ring 16 is sleeved on the open bracket 12, and the height of the pulley 15 is higher than that of the lantern ring 16; the open end of the open bracket 12 is in clearance fit with the surface of the insulating layer 2; the nondestructive testing probes are positioned at the top of the support 11 and distributed in an array manner, generate a pulse magnetic field, enable the pipeline 13 in the insulating layer 2 to generate eddy currents under the action of the pulse magnetic field, induce the magnetic field generated by the eddy currents and output testing signals. The pulley 15 may be a universal wheel. The collar 16 may be an openable collar 16 and the collar 16 may snap closed.

Preferably, the nondestructive testing probe can comprise an electromagnetic transmitting coil and an electromagnetic receiving coil which are coaxially wound; the electromagnetic transmitting coil and the electromagnetic receiving coil can be wound on the magnetic core bodies such as the iron core and the like.

The data acquisition system also comprises a pulse signal generator and an analog-to-digital converter; the microprocessor 8 can control the pulse signal generator to output a pulse signal to the electromagnetic transmitting coil; the electromagnetic transmitting coil can generate a pulse magnetic field, the electromagnetic receiving coil can induce the magnetic field generated by the eddy current and output a detection signal, the analog-to-digital converter converts an analog signal detected by the electromagnetic receiving coil into a digital signal and outputs the digital signal to the microprocessor 8, and the microprocessor 8 processes the digital signal.

The microprocessor 8, the data acquisition system, the pulse signal generator and the analog-to-digital converter can be constructed by adopting the microprocessor 8, the data acquisition system, the pulse signal generator and the analog-to-digital converter which are suitable in the prior art, and can also be constructed by adopting software or components and parts in the prior art and adopting conventional technical means.

Preferably, the pulse signal generator may include two MOS transistor drivers and four field effect transistors, and the four field effect transistors may constitute an H-bridge circuit; the high and low level output ends of each MOS tube driver can respectively and correspondingly output signals to the control ends of the upper and lower arm field effect tubes on one side of the H-bridge circuit; the microprocessor 8 can simultaneously generate two pulse width modulation signals A and two pulse width modulation signals B; two paths of pulse width modulation signals A can be respectively input to the high-end input ends of the two MOS tube drivers; two pulse width modulation signals B can be respectively input to the low-end input ends of the two MOS tube drivers; the output end of the H-bridge circuit is connected with the electromagnetic transmitting coil. The duty cycles of the pwm signal a and the pwm signal B may be equal.

The pulse width modulation signal A and the pulse width modulation signal B output by the microprocessor 8 can enable the HO end of the MOS tube driver A to be at a high level, the LO end to be at a low level, the HO end of the MOS tube driver B to be at a low level and the LO end to be at a high level; when the output of the end A of the resistor R5 is at a high level and the output of the end B is at a low level, the transmitting probe can excite a forward electromagnetic pulse; when the HO end of the MOS tube driver A is at a low level, the LO end is at a high level, the HO end of the MOS tube driver B is at a high level, and the LO end is at a low level, the A end of the resistor R5 outputs at a low level, and the B end outputs at a high level, the probe excites a negative-going electromagnetic pulse, so that the electromagnetic transmitting coil can generate a bipolar transient electromagnetic pulse signal under the control of the main control circuit.

The data acquisition system can be packaged in the detection box 3, and the detection box 3 is fixedly connected with the support 11.

The MOS tube driver and the field effect tube can adopt the applicable MOS tube driver and the applicable field effect tube in the prior art, and can also adopt software or components in the prior art and adopt the conventional technical means to construct.

Preferably, the data acquisition system may further comprise a filter amplifier; the filter amplifier is connected between the output end of the electromagnetic receiving coil and the input end of the analog-to-digital converter. The filter amplifier may be a differential amplifier.

The filter amplifier and the differential amplifier can be applicable in the prior art, and can also be constructed by software or components in the prior art and by adopting conventional technical means.

Preferably, the data acquisition system can also comprise a driving device for driving the open bracket 12 to move along the surface of the insulating layer 2; the drive means may comprise an axial displacement motor mounted on the mouth support 12, the mouth support 12 being axially displaced along the duct 13 when the axial displacement motor is rotated. The axial moving motor can be connected with the axial roller, so that the axial roller rolls on the surface of the heat preservation layer 2 along the axial direction of the pipeline 13.

Preferably, the driving means may further include a circumferential moving motor mounted on the open-mouth support 12, the open-mouth support 12 moving circumferentially along the pipe 13 when the circumferential moving motor rotates. The axial moving motor can be connected with the circumferential roller, so that the circumferential roller rolls on the surface of the heat preservation layer 2 along the circumferential direction of the pipeline 13. The axial rollers and the circumferential rollers can be alternately contacted with the surface of the insulating layer 2 by arranging pneumatic or electric or mechanical landing gears or adopting other means in the prior art and conventional technology.

The axial moving motor and the circumferential moving motor can be 1 motor, and simultaneously drive the axial roller and the circumferential roller; and arranging a pneumatic or electric or mechanical landing gear or adopting other prior art and conventional technical means to enable the axial rollers and the circumferential rollers to be alternately contacted with the surface of the heat-insulating layer 2.

Preferably, the open end of the open stent 12 may be a telescopic open end, and the open angle of the open end may be 120 ° to 180 °.

Preferably, the top of the open bracket 12 can be a polygon with equal side length which is more than or equal to the width of the support 11; each side of the polygon may be sleeved with a support 11. More than one nondestructive inspection probe can be mounted on each support 11.

Preferably, the nondestructive testing probes can be distributed at equal intervals along the circumferential direction of the surface of the insulating layer 2.

Preferably, the bottom of each support 11 can be provided with two pulleys 15 and four collars 16; the two pulleys 15 can be positioned on the central line of the front and back direction of the bottom of the support 11; the four collars 16 may be symmetrically disposed along the front-to-rear and left-to-right center lines of the base bottom.

The utility model also provides a pipeline 13 nondestructive test method in the portable heat preservation, this method is: arranging a microprocessor 8 and a data acquisition system for nondestructively acquiring the condition data of the pipeline 13 in the insulating layer 2, so that the microprocessor 8 outputs a signal to control the work of the data acquisition system and processes the data acquired by the data acquisition system; the data acquisition system is provided with a nondestructive testing probe and a movable base 4 for mounting the nondestructive testing probe; the movable base 4 is provided with an opening bracket 12 and a plurality of flexibly connected supports 11 which surround the heat insulation layer 2; a pulley 15 and a lantern ring 16 are arranged at the bottom of each support 11, so that the lantern ring 16 is sleeved on the open bracket 12, and the height of the pulley 15 is higher than that of the lantern ring 16; the open end of the open bracket 12 is in clearance fit with the surface of the insulating layer 2; the nondestructive testing probes are positioned at the top of the support 11 and distributed in an array manner to generate a pulse magnetic field, so that the pipeline 13 in the insulating layer 2 generates eddy current under the action of the pulse magnetic field, and the eddy current induces the magnetic field generated by the eddy current and outputs a testing signal.

Preferably, the open end of the open stent 12 may be made a telescoping open end; the opening angle can be made to be 120-180 deg.

The structure and the working principle of the present invention will be further described with reference to a preferred embodiment of the present invention as follows:

the utility model discloses a portable heat preservation interior conduit 13 nondestructive test system comprises microprocessor 8, data acquisition system, battery 6, host computer 7 etc.. The nondestructive testing probe comprises an electromagnetic transmitting coil and an electromagnetic receiving coil which are coaxially wound; the data acquisition system also comprises a pulse signal generator, a filter amplifier and an analog-to-digital converter; the microprocessor 8 controls the pulse signal generator to output a pulse signal to the electromagnetic transmitting coil; the electromagnetic transmitting coil generates a pulse magnetic field, the electromagnetic receiving coil induces the magnetic field generated by the eddy current and outputs a detection signal to the filter amplifier, and the filter amplifier filters and amplifies the detection signal output by the electromagnetic receiving coil and outputs the signal to the analog-to-digital converter; the analog-to-digital converter converts the analog signal output by the filter amplifier into a digital signal and outputs the digital signal to the microprocessor 8, and the microprocessor 8 processes the digital signal. And the processed data is sent to the upper computer 7 through the communication module 9. The upper computer 7 may be a computer. The communication module 9 may be a 485 communication module or a wireless communication module.

The nondestructive testing probe is a testing probe integrating a transmitting coil and a receiving coil, an electromagnetic transmitting coil and an electromagnetic receiving coil are uniformly wound on a magnetic core, and the structure of the nondestructive testing probe is schematically shown in figure 8.

Referring to fig. 7 to 8, during the detection, the DSPIC control chip of the microprocessor 8 generates four PWM signals to control the high-side input HI and the low-side input LI of the two MOS drivers, and the control signals pass through the MOS drivers to rapidly drive the four fets to provide sufficient gate driving current to generate the driving voltage. An H-bridge circuit composed of four field effect transistors can realize power amplification of step signals, and when an HO end of an MOS transistor driver A is at a high level, an LO end of the MOS transistor driver A is at a low level, an HO end of an MOS transistor driver B is at a low level, and the LO end of the MOS transistor driver B is at a high level, an A end output of a resistor R5 is at a high level, and a B end output of the resistor R5 is at a low level, a transmitting probe can excite forward electromagnetic pulses; when the HO end of the MOS tube driver A is at a low level, the LO end is at a high level, the HO end of the MOS tube driver B is at a high level, and the LO end is at a low level, the A end of the resistor R5 outputs at a low level, and the B end outputs at a high level, the probe excites a negative-going electromagnetic pulse, so that the electromagnetic transmitting coil generates a bipolar transient electromagnetic pulse signal under the control of the main control circuit. Meanwhile, the electromagnetic receiving coil can convert electromagnetic signals into voltage signals, the filter amplifier is a differential amplifier consisting of three operational amplifiers, and filtering amplification processing of the received signals is achieved through the filter amplifier. The filter amplifier processes the signal and outputs the processed signal to an analog-to-digital converter (ADC), and the ADC completes analog-to-digital conversion to obtain a transmittable digital signal. The microprocessor 8 outputs the processed signals and transmits the digital signals to the upper computer 7 through the communication module 9 (485 module) for display, storage, processing and analysis.

As shown in fig. 3, the nondestructive testing probes are uniformly distributed in any 120-degree area of the outer wall of the pipeline 13, each probe is attached to the outer surface of the insulating layer 2 in a surrounding manner and is fixed on the movable base 4, and the movable base 4 comprises an opening support 12 and a plurality of flexibly connected supports 11, which surround the insulating layer 2; a pulley 15 and a lantern ring 16 are arranged at the bottom of each support 11, the lantern ring 16 is sleeved on the open bracket 12, and the height of the pulley 15 is higher than that of the lantern ring 16; the open end of the open bracket 12 is in clearance fit with the surface of the heat-insulating layer 2; the nondestructive testing probe is arranged on a threaded hole 17 at the upper part of the support 11 through a screw.

The number of the support 11 is changed to adapt to the change of the outer diameter of the detection pipeline 13, so that the detection of the heat-insulating layer pipelines 13 with different pipe diameters is adapted, and the number of nondestructive detection probes can be properly increased or reduced along with the change of the pipe diameters. The plurality of supports 11 are connected by hinges. Can be by two nonmetal damping hinged joint, the hinge can be according to different pipeline 13 adjustment different angles, has strengthened the adaptability of probe to different detection pipeline 13.

The bottom of each support 11 is provided with a universal pulley 15 which can enable the movable base 4 to move along the surface of the insulating layer pipeline 13 axially or circumferentially under the traction of the external drive traction device 1 or the drive of the internal drive motor of the open bracket 12.

The devices and modules such as the nondestructive testing probe, the pulse signal generator, the filter amplifier and the like can be packaged in a testing box 3 made of a nonmetal protective shell.

As shown in fig. 1 to 2, the output leads of the plurality of nondestructive testing probes can be collectively input into the microprocessor, the microprocessor and the 485 communication module 9 are collectively packaged in a control box by the hub 5, and the control box is connected to the upper computer 7 by the output leads.

As shown in FIG. 3, 6 nondestructive testing probes are grouped into a group, the array is uniformly dispersed in any 120-degree direction of the pipeline 13 and fixed on the support 11, the change of the outer diameter of the testing pipeline 13 can be adapted by changing the number of the supports 11, so as to adapt to the heat-insulating layer pipelines 13 with different pipe diameters, and the number of the equipment probes is also increased or decreased appropriately along with the change of the pipe diameters. Then through the adjustable opening bracket 12, a certain range of opening is reserved on the opening bracket 12 to be used as an obstacle avoidance opening 14.

For the horizontal pipeline 13, if the detection probe is positioned above the pipeline 13, the opening angle of the opening end can be 180 degrees, and the obstacle can be avoided by 180 degrees; for the horizontal pipeline 13, if the detection probe is positioned above the side of the pipeline 13, the opening angle of the opening end can be 150 degrees, and can be 150 degrees; for the horizontal pipeline 13, if the detection probe is positioned below the side of the pipeline 13, the opening angle of the opening end can be 120 degrees, and the obstacle can be avoided by 120 degrees; for a vertical pipe 13, the opening angle of the opening end can be 150 degrees, and the obstacle can be avoided by 150 degrees.

Manual movement measurements are required when the obstruction on the pipe 13 exceeds 180 degrees over its outer diameter.

The movable base 4 comprises an opening bracket 12 and a plurality of flexibly connected supports 11 which surround the heat insulation layer 2; a pulley 15 and a lantern ring 16 are arranged at the bottom of each support 11, the lantern ring 16 is sleeved on the open bracket 12, and the height of the pulley 15 is higher than that of the lantern ring 16; the open end of the open bracket 12 is in clearance fit with the surface of the heat-insulating layer 2; the cartridge 3 is fixed to the holder 11 with screws. Referring to fig. 4, a plurality of holders 11 are flexibly connected by a connection band 10, and the connection band 10 has a certain length margin. The open bracket 12 surrounds the heat insulation layer 2, the open end is in clearance fit with the surface of the heat insulation layer 2, the lantern ring 16 can be an openable lantern ring 16, and the lantern ring 16 can be clamped and closed. This makes it possible to surround the supports 11 outside the insulating layer 2. The purpose of the pulleys 15 is to allow the stable movement of the supports 11 on the pipe wall.

As shown in fig. 1, the open bracket 12 can carry a traction device 1, the traction device 1 provides traction force to make the open bracket 12 move stably along the surface of the insulating layer 2 in the axial direction, and the upper computer 7 and the like are placed outside the field and reserve a transmission wire with a sufficient length. By attaching the nondestructive testing probe to the outer pipe wall in an annular array mode, annular testing is realized, and the nondestructive testing probe can synchronously slide along the circumferential direction or the axial direction of the pipe wall of the insulating layer 2.

Transient electromagnetism is a method of detecting the resistivity of a medium by emitting a primary pulsed magnetic field into the ground using an ungrounded return line or a grounded line source, and observing a secondary induced eddy current field induced in the underground medium using a coil or a grounded electrode during the interval of the primary pulsed magnetic field. The working method is that a transmitting coil which is electrified with a certain waveform current is arranged on the ground or in the air, so that a primary electromagnetic field is generated in the surrounding space of the transmitting coil, and an induced current is generated in the underground conductive rock ore body; after power is off, the induced current decays over time.

After the metal pipeline 13 is in service for a long time, a series of chemical reactions occur to further corrode, so that the metal quantity of the pipeline 13 is lost, corrosion products are accumulated, and the physical properties of the wall of the metal pipeline are changed, namely the electrical conductivity and the magnetic conductivity are reduced due to the reduction of the metal quantity. The change can be found through the pulse eddy current detection, and the corrosion section of the pipeline 13 can be judged by processing the data through a corresponding analytical algorithm, so that a scientific evaluation result is given to the corrosion condition of the pipeline 13. The pulsed eddy current detection technology is also called Transient Electromagnetic Method (TEM), and the advantages of the TEM detection method are mainly embodied in the following two aspects: 1) The TEM signal has rich frequency components, and the ultralow frequency eddy current signal contained in the TEM signal can penetrate through the pipe wall with a certain thickness, so that the extraction of the deeper defect information of the pipeline 13 is realized, and the influence of the skin effect is overcome to a certain extent. 2) The amplitude of a magnetic field excited by an exciting coil of the TEM sensor is large, and signal detection can be performed under a large lift-off distance.

The above-mentioned embodiments are only used for illustrating the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, the scope of the present invention should not be limited by the embodiment, that is, all equivalent changes or modifications made by the spirit of the present invention should still fall within the scope of the present invention.

Claims (10)

1. A movable nondestructive testing system for pipelines in an insulating layer is characterized by comprising a microprocessor and a data acquisition system for nondestructively acquiring data of the pipeline conditions in the insulating layer, wherein the microprocessor outputs signals to control the work of the data acquisition system and processes the data acquired by the data acquisition system; the data acquisition system comprises a nondestructive testing probe and a movable base for mounting the nondestructive testing probe; the movable base comprises an opening bracket surrounding the heat-insulating layer and a plurality of flexibly connected supports; the bottom of each support is provided with a pulley and a lantern ring, the lantern ring is sleeved on the opening support, and the height of the pulley is higher than that of the lantern ring; the opening end of the opening bracket is in clearance fit with the surface of the insulating layer; the nondestructive testing probes are positioned at the top of the support and distributed in an array manner, generate a pulse magnetic field, enable the pipeline in the insulating layer to generate eddy currents under the action of the pulse magnetic field, induce the magnetic field generated by the eddy currents and output testing signals.

2. The system for nondestructive testing of pipelines inside a movable heat insulation layer according to claim 1, wherein the nondestructive testing probe comprises an electromagnetic transmitting coil and an electromagnetic receiving coil which are coaxially wound; the data acquisition system also comprises a pulse signal generator and an analog-to-digital converter; the microprocessor controls the pulse signal generator to output a pulse signal to the electromagnetic transmitting coil; the electromagnetic transmitting coil generates a pulse magnetic field, the electromagnetic receiving coil induces the magnetic field generated by the eddy current and outputs a detection signal, the analog-to-digital converter converts an analog signal detected by the electromagnetic receiving coil into a digital signal and outputs the digital signal to the microprocessor, and the microprocessor processes the digital signal.

3. The system for nondestructive testing of pipelines in a mobile insulating layer according to claim 2, wherein the pulse signal generator comprises two MOS transistor drivers and four field effect transistors, the four field effect transistors forming an H-bridge circuit; the high and low level output ends of each MOS tube driver respectively correspond to the control ends of the upper and lower arm field effect tubes on one side of the H-bridge circuit; the microprocessor simultaneously generates two pulse width modulation signals A and two pulse width modulation signals B; two paths of pulse width modulation signals A are respectively input to the high-end input ends of two MOS tube drivers; two pulse width modulation signals B are respectively input to the low-end input ends of the two MOS tube drivers; the output end of the H-bridge circuit is connected with the electromagnetic transmitting coil.

4. The system according to claim 2, wherein the data acquisition system further comprises a filter amplifier; the filter amplifier is connected between the output end of the electromagnetic receiving coil and the input end of the analog-to-digital converter.

5. The system for nondestructive testing of a pipeline inside a movable heat-insulating layer according to claim 1, wherein the data acquisition system further comprises a driving device for driving the open bracket to move along the surface of the heat-insulating layer; the driving device comprises an axial moving motor arranged on the open bracket, and the open bracket moves axially along the pipeline when the axial moving motor rotates.

6. The system of claim 5, wherein the driving device further comprises a circumferential moving motor mounted on the open support, and the open support moves circumferentially along the pipe when the circumferential moving motor rotates.

7. The system for nondestructive testing of pipelines within a mobile insulating layer according to claim 1, wherein the open end of the open support is a telescoping open end with an opening angle of 120 ° to 180 °.

8. The nondestructive testing system for the pipelines in the movable heat-insulating layer according to claim 1, wherein the top of the open bracket is a polygon with equal side length which is more than or equal to the width of the support; each side of the polygon is sleeved with a support.

9. The system of claim 1, wherein the nondestructive testing probes are circumferentially and equidistantly distributed along the surface of the insulation layer.

10. The system for nondestructive testing of pipelines within a mobile insulating layer according to claim 1, wherein the bottom of each support is provided with two pulleys and four collars; the two pulleys are positioned on the central line of the bottom of the support in the front-back direction; the four lantern rings are symmetrically arranged along the central line of the bottom of the base in the front-back direction and the left-right direction.

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