Polyethylene pipeline hot melting joint detection method, system, equipment and medium

Abstract

The invention discloses a method, a system, equipment and a medium for detecting a polyethylene pipeline hot melting joint, and the method comprises the following steps: an isolator deploys a microwave signal source and a microwave probe before detection to obtain the microwave signal source and the microwave probe which meet working conditions; after the microwave signal source sends a first microwave signal in the polyethylene pipeline, the microwave receiver obtains signal information of second microwave signals corresponding to different times of transmission of the hot melting joints, and the microwave receiver is arranged in the microwave probe; the microwave receiver sends signal information of the second microwave signals corresponding to the hot melting joints to the server; the signal information comprises position information and signal reflection parameters of each hot melting joint; and the server detects the position information and the signal reflection parameter in the signal information of the second microwave signal, and determines a target hot melting joint meeting an abnormal detection condition. The method can detect various types of defects, and has the advantages of high detection sensitivity and precision, good reliability and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polyethylene gas pipelines, and particularly to a detection method, system, device and medium for hot-melt joints of polyethylene pipelines. Background Art

[0002] Polyethylene (PE) pipelines are widely used for the transmission of dangerous media such as gas. Polyethylene gas pipelines have many excellent properties, such as low temperature resistance, corrosion resistance, good toughness, anti-cracking, convenient connection (electrofusion connection and hot-melt butt joint), good anti-scratch ability, good crack propagation resistance, etc., and have a relatively long service life. The connection between polyethylene pipes is an important link affecting their structural integrity and long-term strength. Therefore, the safe operation of polyethylene gas pipeline systems is closely related to the quality of their joints.

[0003] The connection methods between polyethylene pipes mainly include two types: hot-melt welding and electrofusion welding. The technology of hot-melt welding is mature and the connection cost is relatively low, which is more common in the case of using large nominal diameter pipes. There are many process parameters for hot-melt welding, and the construction operation is relatively complex. The quality of the joint is highly related to the welding level and experience of the operator.

[0004] Various different defects may exist at the welded joints of polyethylene pipes, mainly including inclusions, lack of fusion, cold welding, etc. Among them, the detection of process defects such as lack of fusion and cold welding is the most difficult, because such defects generally do not show changes in the macroscopic structure of the joint, but have a great impact on the quality and performance of the joint. The defects at the joint pose a great threat to the safety of polyethylene pipelines, and the vast majority of polyethylene pipeline accidents are caused by joint defects. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a detection method, system, device and medium for hot-melt joints of polyethylene pipelines, which have the advantages of being able to detect various types of defects, high detection sensitivity and accuracy, good reliability, etc. In particular, it can effectively detect process defects such as cold welding, with simple operation and low cost.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In a first aspect, a detection method for hot-melt joints of polyethylene pipelines is provided, which is applied to a detection system including a microwave signal source, a microwave probe, an isolator, a microwave receiver and a server. The method includes:

[0008] Before detection, the isolator adjusts the microwave signal source and the microwave probe to obtain a microwave signal source and a microwave probe that meet the working conditions;

[0009] After the microwave signal source sends a first microwave signal in the polyethylene pipeline, the microwave receiver acquires the signal information of the second microwave signals corresponding to different times that penetrate through each hot melt joint, and the microwave receiver is built into the microwave probe;

[0010] The microwave receiver sends the signal information of the second microwave signals corresponding to each hot melt joint to the server; the signal information includes the position information and signal reflection parameters of each hot melt joint;

[0011] The server detects the position information and signal reflection parameters in the signal information of the second microwave signal to determine the target hot melt joint that meets the abnormal detection condition.

[0012] Further, the signal reflection parameter includes the signal voltage value of the second microwave signal corresponding to different times;

[0013] The server detects the position information and signal reflection parameters in the signal information of the second microwave signal to determine the target hot melt joint that meets the abnormal detection condition, including:

[0014] For any hot melt joint, using a preset standing wave algorithm to detect the signal voltage values of the second microwave signals corresponding to different times, and obtaining the standing wave coefficient of the corresponding position information;

[0015] Based on a preset reflection coefficient algorithm, detecting the standing wave coefficient to obtain the reflection coefficient of the corresponding position information;

[0016] Determine the hot melt joint corresponding to the reflection coefficient that meets the abnormal detection condition as the target hot melt joint.

[0017] Further, the preset standing wave algorithm is a simplified crystal calibration method or an equal indication method or a high-frequency method attenuation substitution method.

[0018] Further, the preset reflection coefficient algorithm includes:

[0019]

[0020] Where ρ is the standing wave coefficient, and |Γ L | is the modulus value of the emission coefficient.

[0021] Further, before the server detects the position information and signal reflection parameters in the signal information of the second microwave signal, the method further includes:

[0022] The server measures the received second microwave signal to obtain signal transmission parameters, and the signal transmission parameters include signal attenuation value and signal phase;

[0023] Detect the position information and signal reflection parameters in the signal information of the second microwave signal, including:

[0024] Based on the signal transmission parameters, detect the position information and signal reflection parameters in the signal information of the second microwave signal.

[0025] Further, measure the received second microwave signal to obtain signal transmission parameters, including:

[0026] Adopt the power ratio method or the standing wave amplitude ratio method to measure the received second microwave signal to obtain the signal attenuation value;

[0027] Adopt the transmission wave method to measure the received second microwave signal to obtain the signal phase. The transmission wave method is a method for determining the signal phase shift according to the change amount of the argument of the transmission coefficient.

[0028] In a second aspect, a detection system for a hot melt joint of a polyethylene pipeline is provided, including: a microwave signal source, a microwave probe, an isolator, a microwave receiver, and a server;

[0029] Before detection, the isolator adjusts the microwave signal source and the microwave probe to obtain a microwave signal source and a microwave probe that meet the working conditions;

[0030] The microwave probe placed on one side of the polyethylene pipeline receives the mobile control instruction sent by the server and moves to each hot melt joint based on the mobile control instruction;

[0031] The microwave signal source sends a first microwave signal in the polyethylene pipeline;

[0032] The microwave receiver obtains the signal information of the second microwave signal corresponding to different times transmitted through each hot melt joint. The microwave receiver is built into the microwave probe;

[0033] The microwave receiver sends the signal information of the second microwave signal corresponding to each hot melt joint to the server; the signal information includes the position information and signal reflection parameters of each hot melt joint;

[0034] The server detects the position information and signal reflection parameters in the signal information of the second microwave signal to determine the target hot melt joint that meets the abnormal detection conditions.

[0035] In a third aspect, an electronic device is provided, including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus;

[0036] The memory is used to store a computer program;

[0037] A processor, when executing a program stored in a memory, implements the above-mentioned detection method for the hot-melt joint of a polyethylene pipe.

[0038] In a fourth aspect, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the above-mentioned detection method for the hot-melt joint of a polyethylene pipe is implemented.

[0039] The beneficial effects of the present invention are as follows:

[0040] In the microwave detection method for the hot-melt joint of a polyethylene pipe provided by the present invention, an isolator adjusts the microwave signal source and the microwave probe before detection to obtain a microwave signal source and a microwave probe that meet the working conditions; after the microwave signal source sends a first microwave signal in the polyethylene pipe, a microwave receiver acquires the signal information of the second microwave signals corresponding to different times transmitted through each hot-melt joint, and the microwave receiver is built into the microwave probe; the microwave receiver sends the signal information of the second microwave signals corresponding to each hot-melt joint to a server; the signal information includes the position information and signal reflection parameters of each hot-melt joint; the server detects the position information and signal reflection parameters in the signal information of the second microwave signals to determine the target hot-melt joint that meets the abnormal detection conditions. This method has the advantages of being able to detect various types of defects, high detection sensitivity and accuracy, good reliability, etc. In particular, it can effectively detect process defects such as cold welding, is easy to operate, and has a relatively low cost. Description of the Drawings

[0041] Figure 1 It is a schematic diagram of a principle for measuring the standing wave ratio provided by an embodiment of the present application;

[0042] Figure 2 It is a schematic diagram of a standing wave curve for measuring the standing wave ratio by a simplified crystal calibration method provided by an embodiment of the present application;

[0043] Figure 3 It is a schematic flow diagram of a microwave detection method for the hot-melt joint of a polyethylene pipe provided by an embodiment of the present application;

[0044] Figure 4 It is a schematic diagram of a test system for measuring the single-frequency attenuation by the power ratio method provided by an embodiment of the present application;

[0045] Figure 5 It is a schematic structural diagram of a test system for measuring the single-frequency attenuation by the standing wave amplitude ratio method provided by an embodiment of the present application;

[0046] Figure 6 It is a schematic block diagram of a principle for measuring attenuation and phase shift by the high-frequency substitution method provided by an embodiment of the present application.

[0047] Figure 7Schematic structural diagram of a test system for measuring attenuation by the series substitution method provided by an embodiment of the present application. Detailed implementation manners

[0048] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0049] Embodiment 1

[0050] This embodiment provides a detection method and system for a hot melt joint of a polyethylene pipeline. The detection method can be applied in the detection system, and the system may include: a microwave signal source, a microwave probe, an isolator, a microwave receiver, and a server.

[0051] Among them, the isolator is used to adjust the microwave signal source and the microwave probe before detection to obtain a microwave signal source and a microwave probe that meet the working conditions; the microwave probe is placed on one side of the polyethylene pipeline, and the microwave receiver is built into the microwave probe. The microwave receiver is communicatively connected to the server.

[0052] The server can be a physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, Content Delivery Network (CDN), and big data and artificial intelligence platforms. The terminal can be a user equipment (UE) such as a mobile phone, a smart phone, a laptop computer, a digital broadcast receiver, a personal digital assistant (PDA), a tablet computer (PAD), a handheld device, a vehicle-mounted device, a wearable device, a computing device, or other processing devices connected to a wireless modem, a mobile station (MS), a mobile terminal, etc. The terminal and the server can be directly or indirectly connected through wired or wireless communication methods, and the present application does not make any limitations here.

[0053] Furthermore, the system may further include an indicator. After the server determines a target hot melt joint that meets the abnormal detection conditions, the server sends an abnormal information to the indicator, and the abnormal information includes that the target hot melt joint at the target position is abnormal.

[0054] Furthermore, the factors affecting the microwave detection results of hot-melt joints may include:

[0055] ① Frequency. The dielectric constant, also known as the permittivity or relative permittivity, is an important data characterizing the electrical properties of dielectrics or insulating materials, commonly denoted by ε. When an external electric field is applied to a dielectric, induced charges will be generated, weakening the electric field. The ratio of the original external electric field (in vacuum) to the electric field in the final dielectric is the dielectric constant. It represents the relative ability of a dielectric to store electrostatic energy in an electric field. For example, when a substance with a dielectric constant of ε is filled into a capacitor plate, its capacitance can be increased by ε times. The smaller the dielectric constant, the better the insulation.

[0056] Dielectric loss refers to the energy loss of a dielectric placed in an alternating electric field, manifested as internal heating. The dielectric loss angle is the complementary angle of the angle between the current phasor and the voltage vector flowing through the dielectric when an alternating voltage is applied to the dielectric. The tangent of the dielectric loss angle is the tangent value of the complementary angle δ of the phase angle between the applied voltage and the current of the same frequency when a sinusoidal voltage is applied to the dielectric - tgδ. Its physical meaning is: the energy of dielectric loss in each cycle, the energy stored in the dielectric in each cycle.

[0057] The tangent of the dielectric loss angle is often used to characterize the dielectric loss of a dielectric. Dielectric loss refers to the phenomenon that a dielectric heats up itself due to the consumption of part of the electrical energy in an alternating electric field. The reason is that the dielectric contains charge carriers that can conduct electricity. Under the action of an external electric field, a conduction current is generated, consuming part of the electrical energy and converting it into heat energy. Any dielectric has energy loss under the action of an electric field, including the loss caused by conductance and the loss caused by certain polarization processes.

[0058] The dielectric constant is a function of frequency; with the change of frequency, the dielectric parameters such as the dielectric constant and dielectric loss of most dielectric materials will increase or decrease significantly, and some materials will even change by several orders of magnitude. Because the polarization effect of dielectric materials determines the dielectric constant and also has a great influence on dielectric loss. In addition, there is a large relationship between conductance loss and dielectric loss, and both polarization and conductivity change with the change of frequency. Therefore, the dielectric parameters of many materials are significantly affected by frequency. Generally, when the electric field frequency is lower than the polarization frequency of the material, the dielectric constant of the material is large; conversely, the dielectric constant is small.

[0059] Regardless of the polarization method, there is a corresponding relaxation frequency. If the frequency of the applied electric field exceeds the specific relaxation frequency of this polarization method, it will cause this polarization method to be unable to keep up with the change of the electric field. At this time, this polarization method makes no contribution to the dielectric constant of the entire material. Therefore, as the frequency continuously increases, there will be a step-like decrease in the dielectric constant of the material near the relaxation frequency. In dielectric materials, the greater the proportion of this polarization method among all polarization methods, the greater the decrease in the dielectric constant near the relaxation frequency unique to this polarization method. Polarization is a process and cannot be completed instantaneously. All forms of polarization require time. When the frequency of the applied electric field increases to a level where a certain polarization cannot be formed in time, then the polarization does not exist.

[0060] When the temperature of the medium is relatively low, the thermal motion of the particles is not very intense, the resistance is large, and the polarization is weak; when the temperature is relatively high, the thermal motion of the particles is intense, the resistance is small, the polarization is enhanced, the loss is small, and the tangent of the dielectric loss angle is also small; only at a certain temperature, when the time required for the polarization of the dielectric to be established is close to the change period of the applied voltage, the loss is the largest and the tangent of the dielectric loss angle appears at its maximum value.

[0061] ② Temperature. Temperature affects the internal structure and molecular motion of the material, and also affects the polarization intensity and polarization time. When the frequency is within a certain range, the dielectric properties of the dielectric are significantly affected by temperature. As the temperature increases, the viscous resistance of the orientational polarization will decrease, thereby increasing the dielectric constant of the material. However, while the temperature is increasing, it will also cause the molecules to accelerate their thermal motion, resulting in the disruption of the regular motion of the dipoles and a decrease in the dielectric constant. Therefore, appropriate temperature increase is beneficial to increasing the dielectric constant, but the polarization of the dielectric cannot keep up with the change of the electric field, so there will still be a peak in the dielectric loss. When the temperature reaches a relatively high value, the formation speed of the dipole-oriented molecules cannot keep up with their decomposition speed, which will weaken its polarization effect and enable the polarization of the dielectric to catch up with the change of the electric field. At this time, the dielectric constant will show a trend of first increasing and then decreasing, while the dielectric loss continuously decreases.

[0062] ③ Humidity. After the material absorbs water and gets damp, the dielectric constant of water is very large, and at the same time, water increases the interlayer polarization effect, so the polarization and the dielectric constant increase; the stronger the polarity of the material, the more obvious the influence of humidity. The main reason is that the action of high humidity causes water molecules to diffuse between the molecules of the polymer, enhancing its polarity; at the same time, the humid air acts on the surface of the plastic, and almost within a few minutes, a water film is formed on the surface of the dielectric, which has ionic properties and can increase the surface conductance, thus increasing the dielectric constant of the material. After the dielectric absorbs moisture, the dielectric constant increases, but the specific conductance increases more slowly. Due to the increase in the conduction loss and the relaxation polarization loss, the tangent of the dielectric loss angle increases. For example, when the water content in the paper increases from 4% to 100%, the tangent of the dielectric loss angle can increase by 100 times. Therefore, attention should be paid to the surrounding environment of the dielectric in specific applications.

[0063] ④ Density. The dielectric constant of various woods increases with the increase of wood density. There is little difference in the dielectric constant of different tree species with the same density. The reason is that when the density increases, the content of cell wall substances increases, and thus the number of dipoles also increases, resulting in an increase in the dielectric constant.

[0064] ⑤ Grain direction. When the temperature, frequency, density, and moisture content are the same, the stiffness and brittleness of wood. When the electric field direction is along the grain, its dielectric constant is 30%-60% larger than that across the grain. This is mainly due to the difference in wood structure. The arrangement direction of cellulose macromolecules is mostly close to the direction of the fiber axis. Because the hydroxyl group has more freedom in the direction parallel to the fiber than in the perpendicular direction. The radial dielectric constant across the grain is often slightly higher than or approximately equal to the tangential dielectric constant. The reason is that in addition to the influence of wood rays, the lignin content in the tangential wall of wood cells is high, and the dielectric constant of lignin is smaller than that of cellulose. Therefore, the dielectric constant of wood decreases with the increase of lignin content.

[0065] ⑥ Wall thickness. The uneven wall thickness of polyethylene pipes may cause attenuation or reflection of microwave signals, thus affecting the detection results.

[0066] ⑦ Pipe surface condition. The roughness, pollution, moisture, etc. on the surface of polyethylene pipes will also affect the results of microwave non-destructive testing. Higher roughness and pollution may cause attenuation of microwave signals and reduce the detection accuracy; moisture may cause scattering of microwave signals and affect the detection results.

[0067] ⑧ Background noise. During the process of microwave non-destructive testing, background noise will affect the detection results. Electromagnetic interference from the external environment, noise of the equipment itself, etc. may all cause interference to the detection signal, thus affecting the detection results. In order to reduce the influence of background noise, corresponding shielding measures should be taken to improve the signal-to-noise ratio of the detection signal.

[0068] I. Measurement of reflection parameters

[0069] Reflection parameters are important indicators to describe the mismatch degree of microwave components or sub-assemblies. The usually proposed technical indicators are standing wave ratio, reflection coefficient, input impedance, etc. Among them, the reflection coefficient and input impedance are essentially the same. Therefore, it is necessary to focus on measuring the standing wave ratio and input impedance.

[0070] 1. Standing wave ratio

[0071] The standing wave ratio is the ratio of the maximum voltage value to the minimum voltage value on the transmission line. Therefore, the measurement of the standing wave ratio can be transformed into the measurement of the maximum voltage value and the minimum voltage value on the transmission line. The methods for measuring the maximum voltage value and the minimum voltage value on the transmission line include the direct method, the substitution method, etc. The direct method is to directly measure the voltage and then calculate the ratio. The substitution method is to use the high-frequency attenuation substitution of the ratio obtained by the attenuation of the attenuator. The commonly used methods for measuring the standing wave ratio can include crystal calibration, the direct method, and the simplified crystal calibration method for measuring the standing wave ratio.

[0072] As Figure 1 shown in the schematic diagram of measuring the standing wave ratio, it can be seen that by moving the probe, the high-frequency voltage at a maximum point and the voltage at an adjacent minimum point on the standing wave curve are read out, and the ratio of them can be taken to obtain the standing wave ratio ρ. When the probe picks up the magnitude of the high-frequency voltage, it is usually represented by the current output after detection. Therefore, it is necessary to clarify the relationship between the detected current and the high-frequency voltage, so as to solve the crystal detection law required in the detection.

[0073] i = Cu n 1-1

[0074] In the formula, C is a constant related to the performance of the crystal detector; n is the crystal detection law of the crystal detector, and formula 1-2 is obtained from formula 1-1:

[0075]

[0076] Substituting formula 1-2 into the definition of the standing wave ratio, there is:

[0077]

[0078] In the formula, i max and i min are obtained from the readings of the indicator after detection. To measure the standing wave ratio ρ, it is first necessary to measure the crystal detection law n of the crystal detector, that is, to calibrate the crystal.

[0079] The relational expression 1-1 describing the voltage across the crystal detector and the detected current holds for any load to be measured. It also holds for a short-circuit breaker with Γ = -1. However, when the output end of the measuring line is connected to a short-circuit breaker, the electromagnetic wave in the measuring line is a pure standing wave, and the voltage at any point on the transmission line can be expressed as:

[0080]

[0081] In the formula, d is the distance from this point to the breakdown point. Substituting 1-4 into formula 1-1 and taking the relative value of the current, there is:

[0082]

[0083] From this, the crystal detection law is obtained as:

[0084]

[0085] Compare the measured data i in Formulas 1-6 with the calculated value Plot a curve on a full logarithmic coordinate system, and the slope of this curve is the crystal detection law n.

[0086] Substitute the measured crystal detection rate n into Formulas 1-3, and the standing wave ratio can be directly measured.

[0087] Following the method of crystal calibration, the standing wave ratio of the load to be measured can also be measured. It compares the readings i max and i min of the detector indicator for measuring the standing wave ratio of the load to be measured with the known voltage standing wave pattern (half-cycle sine wave) when the measuring line terminal is connected to a short-circuit breaker. However, at this time, only the i max and i min corresponding to the two reading points for measuring the standing wave ratio need to be compared, and the relative values of the high-frequency voltages u max and u min represented by these two readings are determined, and thus their ratio ρ can be determined. Since only two points are taken instead of finding the relationship between i and u at many points within the entire available level range, it is called the simplified crystal calibration method.

[0088] The specific method of the simplified crystal calibration method: Arrange the measuring line system as Figure 1 shown: Behind the isolator, connect a level-adjusting attenuator. First, connect the load to be measured at the measuring line terminal, adjust the signal level, and make the detector indicator read clear i max and i min , record these two values, and then change the measuring line terminal to a good short-circuit breaker. At this time, increase the level-adjusting attenuator until the maximum reading during short-circuit is exactly equal to the wave amplitude point i max reading last time. As Figure 2 shown, find the position of a P1 point on the short-circuit standing wave curve, and the reading of this point is exactly equal to the wave node reading i min last time. Determine the distance d1 between the P1 point and the nearest wave node from the probe position scale, then we can get:

[0089]

[0090] Thus, we get:

[0091]

[0092] To prevent the maximum point of the standing wave curve during short-circuit from shifting due to the probe electrical sodium effect, resulting in an asymmetric curve and thus causing a change in d1, a point P2 at the same height as the P1 point can be found on the curve on the other side of the wave node, and the distance D = d1 + d2 between the P1 and P2 points is measured. Then:

[0093]

[0094] In this way, this influence of the probe (loading) effect can be eliminated. The simplified crystal calibration method is simple and easy to implement. As long as D is found, it can be calculated, and it has nothing to do with the crystal detection law. This method can be used to measure the standing wave coefficient when the crystal detection law is unknown.

[0095] The preferred embodiments of the present application will be described below in conjunction with the accompanying drawings of the specification. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. And without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0096] Figure 3 It is a schematic flowchart of a detection method for a hot melt joint of a polyethylene pipe provided by an embodiment of the present application. As Figure 3 shown, the method may include:

[0097] Step S310: Before detection, the isolator tunes the microwave signal source and the microwave probe to obtain a microwave signal source and a microwave probe that meet the working conditions.

[0098] Step S320: After the microwave signal source sends a first microwave signal in the polyethylene pipe, the microwave receiver acquires the signal information of the second microwave signals corresponding to different times transmitted through each hot melt joint.

[0099] After the microwave signal source sends a first microwave signal in the polyethylene pipe, the microwave probe moves on one side of the polyethylene pipe. Thus, the microwave receiver built into the microwave probe can collect the signal information of the second microwave signals corresponding to different times transmitted through each hot melt joint.

[0100] It can be understood that if a certain hot melt joint has no abnormality, the microwave receiver cannot collect the signal information of the second microwave signal transmitted through the hot melt joint.

[0101] Step S330: The microwave receiver sends the signal information of the second microwave signals corresponding to each hot melt joint to the server.

[0102] The signal information may include the position information of each hot melt joint and the signal reflection parameters. The signal reflection parameters may include information carried by the reflected signals such as the signal voltage value, signal intensity, frequency, etc. of the second microwave signals corresponding to different times.

[0103] Step S340: The server detects the position information and the signal reflection parameters in the signal information of the second microwave signals to determine the target hot melt joints that meet the abnormal detection conditions.

[0104] For any hot melt joint, the preset standing wave algorithm is used to detect the signal voltage values of the second microwave signals corresponding to different times, and the standing wave coefficient of the corresponding position information is obtained; the preset standing wave algorithm is the simplified crystal calibration method or the equal indication method or the high-frequency method attenuation substitution method.

[0105] Based on the preset reflection coefficient algorithm, the standing wave coefficient is detected to obtain the reflection coefficient of the corresponding position information; the preset reflection coefficient algorithm can be expressed as:

[0106]

[0107] where ρ is the standing wave coefficient, and |Γ L | is the modulus value of the emission coefficient.

[0108] The hot melt joint corresponding to the reflection coefficient that meets the abnormal detection condition is determined as the target hot melt joint.

[0109] Further, before the server detects the position information and the signal reflection parameter in the signal information of the second microwave signal, the server can measure the received second microwave signal to obtain the signal transmission parameter, and the signal transmission parameter includes the signal attenuation value and the signal phase;

[0110] After that, based on the signal transmission parameter, the position information and the signal reflection parameter in the signal information of the second microwave signal are detected. Thus, the power ratio method or the standing wave amplitude ratio method is used to measure the received second microwave signal to obtain the signal attenuation value; the transmission wave method is used to measure the received second microwave signal to obtain the signal phase, and the transmission wave method is a method to determine the signal phase shift according to the change amount of the argument of the transmission coefficient.

[0111] Among them, the equal indication method is used to measure the standing wave coefficient. The direct method and the simplified crystal calibration method are only suitable for measuring medium and small standing wave coefficients. When measuring a large standing wave ratio, it will be difficult to accurately measure i min or D. Although methods such as changing the range or using a micrometer can be used to help solve the problem, it is still difficult to measure accurately.

[0112] When measuring medium and large standing wave coefficients, since the voltage at the minimum point is very small, sometimes it is necessary to increase the probe depth to obtain a clear reading. However, when the probe is moved to the maximum point, such a large probe admittance will cause a significant decrease in the maximum reading, resulting in a large error in the calculated standing wave coefficient value. At the same time, since the level at the maximum point is much different from that at the minimum point, within such a wide level range, it is difficult to maintain the crystal detection law consistently. All these make it impossible to measure large standing wave coefficients according to the conventional method, and some flexible methods need to be adopted. The most suitable method for measuring large standing wave coefficients is the "equal indication method". This method usually only finds two points on both sides of a certain minimum point (i.e., wave node) where the indicator readings are equal to twice the minimum value, measures the distance D between them, and then the value of the standing wave coefficient to be measured can be obtained from this. Since the larger the standing wave coefficient, the less the size and position of the minimum point are affected by the probe. By only measuring near the minimum point and avoiding the measurement of the maximum value, the probe error can be reduced to a negligible level. At the same time, because only the lower levels near the minimum point are involved, it is generally easy to keep the crystal in the square law. Under the square law condition, doubling the indicator reading means doubling the power, so this method is also called the power doubling method and the 3dB width method.

[0113] The principle block diagram of measuring the standing wave coefficient by the equal indication method is the same as Figure 1 shown. When the terminal terminates the load, the electromagnetic wave in the measuring line can be written as:

[0114]

[0115] The phase of the wave node of the standing wave is π, so the voltage of the electromagnetic wave at the wave node is (|u i | = 1, the same below):

[0116]

[0117] Its detected current is

[0118] i min = C(1 - |Γ L |) n 1 - 12

[0119] Suppose the point where the detected current is k times that at the wave node is at a distance d from the wave node, and its phase is π ± 2βd. Then the voltage of the electromagnetic wave at the point at a distance d from the wave node is:

[0120] (1 + |Γ| 2 + 2|Γ|cos(π ± 2βd)) 1 / 2 = (1 + |Γ| 2 - 2|Γ|cos(2βd)) 1 / 2 1 - 13

[0121] The output current after being detected by the detector is:

[0122] i=k·i min =[1+|Γ| 2 -2|Γ|cos(2βd)] n / 2 1-14

[0123] Divide Equation 1-14 by Equation 1-12 and use the trigonometric formula cos2θ=2cos 2 θ-1 and After transformation and simplification, the calculation formula of the standing wave coefficient can be obtained, namely:

[0124]

[0125] When the standing wave is large, is a very small angle. To simplify further, let sin(βd)=βd,cos(βd)=1, then we can get:

[0126]

[0127] For ease of measurement and to prevent waveform asymmetry due to probe loading effects, the distance D between two double minimum points on either side of the minimum point is usually read, so:

[0128]

[0129] In summary, Equation 1-17 is only valid when measuring large VSWRs. When the VSWR is 10, the measurement error of Equation 1-17 is less than 5%. The error decreases with larger VSWRs. When the VSWR is larger, D decreases, making accurate measurement difficult. A micrometer can be used for measurement.

[0130] (3) High-frequency attenuation substitution method for measuring standing wave coefficient

[0131] The direct method and the equal indication method are both methods related to the crystal detection law. The high frequency attenuation substitution method for measuring the standing wave coefficient has nothing to do with the crystal detection law. Figure 1 The variable attenuator in the circuit is replaced by a calibrated precision attenuator. The high-frequency attenuation substitution method can be used to measure large, medium, and small standing wave coefficients. The method is as follows: first, amplify the precision attenuator to a certain large attenuation value position, read its reading as A1 (dB), accurately move the probe to the maximum point of the standing wave, record the reading of the detection indicator at this time as i, then move the probe to the minimum point, while reducing the attenuation, and fine-tune the precision attenuator so that the detection indicator reading is still restored to i. Assuming that the attenuator reading at this time is reduced to A2 (dB), it can be obtained that the maximum value of the measured standing wave voltage is greater than the minimum value by ΔA = (A1-A2) dB, so:

[0132]

[0133] In the high-frequency substitution method, the i readings at the maximum and minimum points are equal, and the crystal detector operates at the same level. Therefore, the result measured by this method is independent of the crystal detection law. This method is applicable to medium and large standing wave coefficients. However, when the signal level is properly selected so that the precision attenuator operates in a more open part of its scale, that is, the scale resolution is high enough, and the amplitude stability of the signal source is good enough, this method can also measure small standing wave coefficients.

[0134] 2. Reflection Coefficient and Impedance

[0135] The reflection coefficient and impedance are two ways to describe the same problem. Therefore, the measurement of the reflection coefficient will be mainly introduced. The reflection coefficient is a vector, including two parts: amplitude and phase. The modulus of the emission coefficient can be obtained by measuring the standing wave coefficient through Equation 1-19.

[0136]

[0137] It can be seen from Equation 1-20 that the measurement of the reflection coefficient only needs to solve the phase of the emission coefficient. The idea of measuring the phase of the load under test: First, find a known phase point on the measuring line, such as the amplitude point and the wave node point, and then convert the distance from this point to the end face of the load under test into an angle.

[0138] When measuring, the position of the minimum point in the standing wave pattern in the transmission line is less affected by the probe current. Therefore, when determining the phase of the reflection coefficient, generally the position of the minimum point is used as the basis. Therefore, when measuring the argument of the reflection coefficient, it is necessary to measure the distance from the end face of the load to a minimum point (wave node).

[0139] II. Measurement of Transmission Parameters

[0140] When electromagnetic waves pass through microwave propagation devices, in addition to the change in amplitude, the phase also changes. This change mainly depends on the characteristics of the device itself. The measurement of multi-port devices can be reduced to the measurement of two-port devices. The parameters characterizing the transmission characteristics of the two-port network itself are s in its scattering parameters. 21 , for a passive network, the modulus value |s| expressed in decibels 21 | is used as the characteristic transmission loss of the network, that is, attenuation. At the same time, the argument arg(s 21 ) is used as the characteristic phase shift of the network, that is, phase shift. There are many methods for measuring transmission parameters. In addition to mainly introducing the method of measuring attenuation and phase shift using the measuring line method, the attenuation-phase shift measurement method often used in actual measurement will also be introduced.

[0141] 1. Attenuation Measurement

[0142] (1) Power Ratio Method

[0143] The power ratio method is the most basic method for measuring network attenuation according to the definition. It uses various small power meters or square-law detection indicators to directly measure the relative power ratio before and after the network is inserted, and then determines the attenuation of the network to be measured. The power ratio method is relatively simple in equipment during point-frequency measurement and has a certain accuracy. Therefore, it is one of the most commonly used methods for measuring attenuation.

[0144] Figure 4 Figure 4 shows a test system for measuring single-frequency attenuation by the power ratio method. Before measurement, both the signal source and the power meter (a thermocouple power meter probe with a large dynamic range and good stability should be used) need to be adjusted with a tuner. Then, measure the power P1 before the network is inserted and the output power P2 after the network is inserted. According to the attenuation A described above, it can be defined as the insertion loss of the network in a fully matched system, that is

[0145]

[0146] The measurement range of this method mainly depends on the measurement range of the power meter. Its measurement error includes not only the error introduced by the mismatch of the test system, but also the errors introduced by the zero drift of the thermosensitive element of the power meter and the instability of the output power of the signal source, etc. However, by carefully adjusting and stabilizing the signal source, a relatively high measurement accuracy can be obtained. Since the relative power indicator composed of a square-law detector and a measurement amplifier can also play the role of a power meter, the power meter in Figure 4 can be replaced with a square-law detector and a measurement amplifier.

[0147] (2) Standing wave amplitude ratio method

[0148] If the attenuation of the network to be measured is in the small attenuation range, the standing wave amplitude ratio method can be used. As Figure 5 shown, when the network to be measured for attenuation is inserted into a test system with a short circuit at the terminal. At this time, for curve ② in the standing wave distribution on the line, the standing wave amplitude is E m2 ; if the attenuation network is not inserted, the standing wave distribution on the line is as shown in curve ①, and its electric field distribution can be expressed by a sine function, that is:

[0149]

[0150] In the formula, E m1 is the standing wave amplitude point; is the point on curve ① of amplitude E m2 that is equal to the distance from the standing wave node, then:

[0151]

[0152] Then, using the definition that the attenuation A is the insertion loss of the network in a fully matched system:

[0153]

[0154] Equation 2-4 shows that the attenuation of the network under test is related to its standing wave distribution and is a function of ω and λ g , so the measurement line region can be used to determine its attenuation by measuring the standing wave. During the measurement, the amplitude E of the standing wave on the measurement line after inserting the network under test is used as the equal indication degree, and then the width ω and the waveguide wavelength λ are measured on the standing wave pattern when the network under test is not inserted m2 , and the attenuation amount of the decrease in the standing wave amplitude is calculated. It is also difficult to measure the attenuation amount above 5 dB by this method because ω is very difficult to measure accurately at this time, but the main feature of this method is that the measurement of attenuation has nothing to do with the detection characteristics of the detector. g

[0155] 2. Phase Measurement

[0156] There are mainly the reflection method and the transmission wave method for measuring the phase shift using a measurement line. Since the measurement error of the reflection wave method is relatively large and it is only suitable for lossless or low-loss components, it is not widely used in actual measurements. Only the transmission wave method is introduced below.

[0157] The transmission wave method is a method for determining the signal phase shift corresponding to the component under test based on the change in the argument of the transmission coefficient.

[0158] Usually, for the first directional coupler, the incident wave coupled to the measurement line is proportional to the incident wave of the component under test. The outgoing wave coupled to the output end of the measurement line through the directional coupler is proportional to the outgoing wave at the output end of the component under test. These two waves interfere with each other during the reverse transmission process to form a standing wave. The phase shift amount can be determined based on the positions of the standing wave nodes before and after inserting the component under test. The incident wave and the reflected wave at a certain point O on the measurement line branch are respectively:

[0159]

[0160]

[0161] In the formula, K1 and K2 are respectively the voltage coupling coefficients of the first directional coupler and the second directional coupler. l1 is the distance from the reference point O to point D through the directional coupler 1, and l2 is the distance from the reference point O along the component under test and the directional coupler to point D. The electric field at point D is:

[0162]

[0163] When point D is a wave node, there is:

[0164]

[0165] Let l = l1 + l2, there is

[0166]

[0167] Where θ0 is a constant.

[0168] In actual measurement, the measuring line is used to measure the waveguide wavelength, the node D1 before the DUT is inserted (replaced by a straight waveguide), and the node D2 to the right of D1 after the DUT is inserted. The phase shift of the DUT is obtained according to the formula:

[0169]

[0170] The transmission wave method is also applicable to high-power measurements, and because the matching condition is improved, the mismatch error is small and the accuracy is high, it can be used to measure lossy components.

[0171] 3. Substitution method for measuring attenuation and phase shift

[0172] The substitution method doesn't fall under the category of line measurement, but it does measure attenuation. The most important and commonly used method for measuring phase shift involves replacing the network under test with a standard attenuator or phase shifter. The signal level indicator (usually a zero-power indicator) connected to the test system terminal remains unchanged, and the change in the standard attenuator or phase shifter before and after the substitution is measured to determine the attenuation or phase shift of the network under test. Substitution methods are generally categorized as high-frequency, medium-frequency, and low-frequency. While these methods all share similar measurement methods, only the high-frequency substitution method will be discussed here.

[0173] The principle block diagram of the high-frequency substitution method for measuring attenuation and phase shift is as follows: Figure 6 As shown, the output power of the signal source is divided into two paths by the input power splitter. One path passes through the network to be tested and is sent to the output power splitter, and the other path passes through the standard attenuator and standard phase shifter and is also sent to the output power splitter. The output power splitter then combines the two signals and sends them to the level indicator. The standard attenuator and standard phase shifter must be adjusted before and after the network to be tested is inserted. When the two signals reach the output power splitter, the amplitudes of the two signals are equal and the phases are opposite. Therefore, after being combined by the power splitter, the indicator indicates "zero" (called zero power indication method). In this way, the attenuation of the network to be tested is equal to the difference between the attenuation of the standard attenuator before and after the network to be tested is inserted, that is, A = A2-A1; similarly, the phase difference of the standard phase shifter can be expressed as the phase shift of the network to be tested, that is, It can be seen that the high-collar substitution method is a method that can measure the amplitude and phase of the network transmission coefficient.

[0174] The zero-power indication method avoids the influence of the output change of the signal source and the sensitivity of the indicator on the measurement accuracy. However, for the convenience of testing, the adjustment of the attenuator and the phase shifter should be independent of each other. That is to say, when the standard attenuator changes the attenuation, its phase shift should be constant, and the loss of the phase shifter should not change with the change of the phase shift amount. It is more appropriate to use a rotating polarization attenuator for the former, and a phase shifter composed of a cascade of a directional coupler and a short-circuit piston can be used for the latter. Since the connection method of the standard attenuator and the phase shifter to the network under test is in parallel during measurement, the accurate name of this method is the parallel high-frequency substitution method.

[0175] In addition to using the parallel high-frequency substitution method to measure attenuation and phase shift, the cascade high-frequency substitution method can also be used to measure attenuation. The principle block diagram of measuring attenuation by the cascade high-frequency substitution method is as Figure 7 shown. During measurement, before inserting the network under test, set the standard attenuator to a large attenuation amount A1, and adjust the output power of the signal source and the sensitivity of the indicator so that the indicator can indicate on a signal level scale that is convenient for reading and stable; then insert the network under test, change the attenuation amount of the standard attenuator to make the indicator return to the original indicated signal level scale. At this time, if the attenuation amount of the standard attenuator is A2, the attenuation amount of the network under test is A = A2 - A1. Obviously, the cascade high-frequency substitution method is very simple. However, in addition to being affected by the mismatch factor, the instability of the output power of the signal source during the substitution process will also introduce measurement errors. Therefore, a stable signal source is required.

[0176] III. Parameter Calibration

[0177] 1) Single-port network calibration method

[0178] According to Equation 3-1, use standard components to find the error terms E DF , E RF and E SF , the method is as follows:

[0179]

[0180] The crosstalk error E DF can be separated by a sliding small reflection load (at this time, Equation 3-1 is approximately Γ M ≈ E EF + E RF Γ L ). The method is: connect the sliding load to the output port T1 of the test device, and move it back and forth (i.e., change the phase) so that a small circular trajectory is displayed on the polar coordinate display. The distance from the center of the small circle to the center of the display is the modulus of the directional vector; the center coordinates of the small circle are E DF . Generally, the circle fitting method is used to find E DFThe modulus value and argument. The number of data points for measuring the fitted circle is generally six points taken at a distance of half a wavelength (the given sliding small reflection load usually gives six sliding card positions or is specified by marked lines).

[0181] Regarding E RF and E SF The method of obtaining them can be achieved by connecting a circuit breaker and an open circuit device respectively on the T1 plane. That is, when short-circuited, the measured value is:

[0182]

[0183] When open-circuited, the measured value is:

[0184]

[0185] Solve for E RF and E SF .

[0186] 2) Two-port network calibration method

[0187] A two-port network has a total of 12 error terms. Currently, there are sub-item calibration methods, the TRL method, and the "electronic" calibration method. The first two methods are mainly discussed, and the third method is briefly introduced.

[0188] A. Sub-item calibration method: The 12 error terms are divided into six in the forward and reverse directions respectively. The reverse and forward calibration methods are the same. Taking the forward direction as an example, the calibration method is as follows: There are six error terms in the forward direction, and six known conditions must be provided according to Equations 3-5 to 3-8.

[0189]

[0190]

[0191]

[0192]

[0193] Among them:

[0194] D1 = 1 - S 11A E SF -S 22A S 21A E LF E SF +S 11A S 22A E SF E LF ;

[0195] D2 = 1 - S 22A E SR -S 11A ELR -S 12A S 21A E LR E SR +S 11A S 22A E SR E LR 。

[0196] (1) Calibrate E DF : Set the selection switch to the S 11 position. To measure E DF , from Equation 6.91, it is known that S 11A = 0, S 12A = S 21A = S 22 = 0 conditions should be provided, that is, a full-absorbing load is connected to the T plane, for S 12A = S 21A = 0, a full-absorbing load can also be connected to T2 to increase the isolation between the two ports of T1 and T2. Measure the reflection coefficient in this state and record it as (The upper right corner number only represents the order number, not the power, the same below), from Equation 3-4, it can be obtained that:

[0197]

[0198] (2) Calibrate E RF and E SF : While maintaining the "1" state, connect a short circuit plate and an open circuit device to the T1 port in turn, so that S 11A = -1 and +1, measure the reflection coefficients respectively and record them as and From Equation 3-4, it can be obtained that:

[0199]

[0200]

[0201] For the open circuit device, if it is obtained by using a quarter-wavelength short circuit device, only the open circuit condition can be obtained at a certain frequency point during the point-by-point frequency sweep measurement. Therefore, the reflection coefficient +1 in the open circuit state can be replaced by the reflection coefficient Γ s = -1×e -j4×x / λ , instead (S is the distance between the short circuit surface of the offset short circuit device and its port, λ g is its waveguide wavelength), Equation 3-6 is written as:

[0202]

[0203] (3) Calibrate E XF : Set the switch to the S 21 position, and connect full-absorbing loads to the test ports T1 and T2 respectively, so that S11A ==S 22A =S 12A =S 21A =0. In this state, measure its forward transmission coefficient. If it is not zero, it indicates the existence of leakage and internal crosstalk, and its indication value is recorded as Obtained from Equation 3-5:

[0204]

[0205] (4) Calibrate E TF : The selection switch remains in the S 21 position. Connect the test ports T1 and T2 together. Make 2 an equivalent two-port network with zero length / zero loss and no reflection, and have S 11A ==S 22A =0, S 12A =S 21A =1. Measure the forward transmission coefficient, and its indication value is recorded as Obtained from Equation 3-5:

[0206]

[0207] (5) Calibrate E LF , the selection switch is placed in S 11 position. Keep the test ports connected together with S 11A ==S 22A =0, S 12A =S 21A =1, test its reflection coefficient, and record it as From

[0208] Equation 3-4:

[0209]

[0210] Simultaneously solve Equations 3-9, 3-10, 3-11 to 3-15 to obtain the six forward error parameters as:

[0211]

[0212]

[0213]

[0214]

[0215]

[0216]

[0217] Equations 3-16 to 3-21 are forward error parameter calibration methods. Similarly, controlled by the selection switch, with test port T2 as the signal input port, the reverse error parameters (6 items) can be calibrated. There are a total of 12 items.

[0218] If, in the forward test working state, the ports T1 and T2 of the network under test are manually changed to test the reverse network parameters (S 12 and S 22 ), then only the six forward error terms need to be obtained. Because at this time, there are E DF = E DR , E SF = E SR , E RF = E RR , E RF = E RR , E TF = E TR , E XF = E XR , E LF = E LR . When measuring the parameters of the network under test, only the measured values S 11M , S 21M , S 22M and S 12M and the obtained error parameters need to be substituted into Equations 3-22 to 3-25 to obtain the true values S 11A , S 21A , S 22A and S 12A .

[0219]

[0220]

[0221]

[0222]

[0223] Where:

[0224] S 11B = (S 11M - E DF ) / E RF ;

[0225] S 21B = (S 21M - E XF ) / E TF ;

[0226] S 12B = (S 12M - E XR ) / ETR ;

[0227] S 22B =(S 22M -E DR ) / E RR ;

[0228] Δ = (1 + S 11B E SF )(1 + S 22B E SR ) - (S 21B S 12B E LF E LR );

[0229] B. Another method for calibrating 12 error parameters is the TRL (Thru-Reflect-Line) calibration method: This method calibrates the error parameters by butting between test ports T1 and T2, connecting a reflection load and a uniform transmission line with the same characteristic impedance as the test port to the two ports respectively. It is equivalent to connecting a known network three times between T1 and T2 to form three working states. Four S-parameters are measured successively in the three working states to obtain 12 equations, and the 12 error parameters can be solved. Now, the error parameters are summarized in Table 3-1.

[0230] Table 3-1 Error Model Parameter Table

[0231]

[0232] (1) Butt T1 and T2 (T state) to form a zero-loss and zero-length transmission line, with S 11A ==S 22A ==0, S 12A =S 21A =1. Measure the four forward and reverse S-parameters, denoted as and From Equations 3-4 to 3-7, we get:

[0233]

[0234]

[0235]

[0236]

[0237] (2) Connect T1 and T2 to loads with the same reflection coefficient Γ r (such as a short circuit board) (R state), with S 11A =S 22A =Γ r, S 12A = S 21A = 0. Measure the S parameters in the same way as the "T" shape, and obtain from Equations 3-4 to 3-7:

[0238]

[0239]

[0240]

[0241]

[0242] (3) Connect T1 and T2 with a standard line of length L (L state), and there is S 11A == S 22A = 0, S 12A = S 21A = e -j2βL , β = 2π / λ g . Measure its S parameters, and obtain from Equations 3-4 to 3-7:

[0243]

[0244]

[0245]

[0246]

[0247] Solve the expressions of 12 error terms from Equations 30 to 35. This method is relatively simple.

[0248] C. Introduction to the "Electronic" Calibration Method (abbreviated as ECal): This calibration method causes relatively large inconsistency errors, mainly for multiple disassembly and assembly of coaxial interfaces. The control unit of the system is connected to the amplitude-phase receiver, measuring device, and "electronic" standard of the AN system through the GP-IB bus.

[0249] The electronic standard is provided by the calibration module. Its power source and driver provide the impedance standard and transmission standard. The microwave circuit of the electronic calibration is controlled by PIN diode switches, not mechanical standards. The standard module gives a precisely known impedance to the test port. To calibrate 12 error terms, multiple impedance standards are required, the TRL calibration method. Store each error term obtained from the calibration in the computer and call it during measurement. Calculate its correction value according to Equations 3-22 to 3-25.

[0250] Since the implementation manners and beneficial effects of each device of the electronic device in the above embodiments can be referred to Figure 3It is implemented by the steps in the embodiments shown. Therefore, the specific working process and beneficial effects of the electronic device provided in the embodiments of this application will not be elaborated here.

[0251] Embodiment 2

[0252] Based on Embodiment 1, this embodiment:

[0253] This embodiment provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the detection method for the hot-melt joint of the polyethylene pipeline in Embodiment 1. Among them, the computer program can be in the form of source code, object code, executable file or some intermediate form, etc.

[0254] Embodiment 3

[0255] Based on Embodiment 1, this embodiment:

[0256] This embodiment provides a computer-readable storage medium, storing a computer program, and when the computer program is executed by the processor, it implements the steps of the detection method for the hot-melt joint of the polyethylene pipeline in Embodiment 1. Among them, the computer program can be in the form of source code, object code, executable file or some intermediate form, etc. The storage medium includes: any entity or device that can carry the computer program code, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the storage medium does not include electrical carrier signals and telecommunication signals.

[0257] It should be noted that for the foregoing method embodiments, for the sake of simplicity of description, they are expressed as a series of action combinations. However, those skilled in the art should know that this application is not limited by the described action sequence, because according to this application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

Claims

1. A detection method for a hot-melt joint of a polyethylene pipeline, characterized in that, Applied to a detection system including a microwave signal source, a microwave probe, an isolator, a microwave receiver, and a server, the method includes: Before detection, the isolator adjusts the microwave signal source and the microwave probe to obtain a microwave signal source and a microwave probe that meet the working conditions; After the microwave signal source sends a first microwave signal in the polyethylene pipe, the microwave receiver obtains the signal information of the second microwave signals corresponding to different times transmitted through each hot melt joint, and the microwave receiver is built into the microwave probe; The microwave receiver sends the signal information of the second microwave signals corresponding to each hot melt joint to the server; the signal information includes the position information and the signal reflection parameters of each hot melt joint; The server detects the position information and the signal reflection parameters in the signal information of the second microwave signal to determine the target hot melt joint that meets the abnormal detection conditions.

2. The detection method of the hot-melt joint of the polyethylene pipe according to claim 1, characterized in that, The signal reflection parameters include the signal voltage values of the second microwave signals corresponding to different times; The server detects the position information and the signal reflection parameters in the signal information of the second microwave signal to determine the target hot melt joint that meets the abnormal detection conditions, including: For any hot melt joint, using a preset standing wave algorithm, detecting the signal voltage values of the second microwave signals corresponding to different times to obtain the standing wave coefficient of the corresponding position information; Based on a preset reflection coefficient algorithm, detecting the standing wave coefficient to obtain the reflection coefficient of the corresponding position information; Determining the hot melt joint corresponding to the reflection coefficient that meets the abnormal detection conditions as the target hot melt joint.

3. The detection method of the hot-melt joint of the polyethylene pipe according to claim 2, characterized in that, The preset standing wave algorithm is a simplified crystal calibration method, an equal indication method, or a high-frequency method attenuation substitution method.

4. The detection method of the hot melt joint of the polyethylene pipeline according to claim 3, characterized in that The preset reflection coefficient algorithm includes: where ρ is the standing wave coefficient and |Γ L | is the modulus of the emission coefficient.

5. The detection method of the hot-melt joint of the polyethylene pipeline according to claim 1, characterized in that, Before the server detects the position information and the signal reflection parameters in the signal information of the second microwave signal, the method further includes: The server measures the received second microwave signal to obtain signal transmission parameters, and the signal transmission parameters include a signal attenuation value and a signal phase; Detecting the position information and the signal reflection parameters in the signal information of the second microwave signal includes: Based on the signal transmission parameters, detecting the position information and the signal reflection parameters in the signal information of the second microwave signal.

6. The detection method of the hot-melt joint of the polyethylene pipe according to claim 5, characterized in that, Measuring the received second microwave signal to obtain signal transmission parameters includes: Using a power ratio method or a standing wave amplitude ratio method to measure the received second microwave signal to obtain the signal attenuation value; Using a transmission wave method to measure the received second microwave signal to obtain the signal phase, and the transmission wave method is a method for determining the signal phase shift according to the change amount of the argument of the transmission coefficient.

7. A detection system for a hot melt joint of a polyethylene pipeline, characterized in that, The system includes: a microwave signal source, a microwave probe, an isolator, a microwave receiver, and a server; Before detection, the isolator adjusts the microwave signal source and the microwave probe to obtain a microwave signal source and a microwave probe that meet the working conditions; The microwave probe placed on one side of the polyethylene pipe receives the mobile control instruction sent by the server and moves to each hot melt joint based on the mobile control instruction. A microwave signal source transmits a first microwave signal in the polyethylene pipeline; A microwave receiver acquires signal information of second microwave signals corresponding to different times transmitted through each hot melt joint, and the microwave receiver is built in the microwave probe; The microwave receiver sends the signal information of the second microwave signals corresponding to each hot melt joint to the server; the signal information includes the position information and signal reflection parameters of each hot melt joint; The server detects the position information and signal reflection parameters in the signal information of the second microwave signal to determine a target hot melt joint that meets the abnormal detection condition.

8. An electronic device, characterized in that, The electronic device includes a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus; The memory is used for storing a computer program; The processor, when executing the program stored on the memory, implements the detection method for the hot melt joint of the polyethylene pipeline according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, it implements the detection method for the hot melt joint of the polyethylene pipeline according to any one of claims 1-6.

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