Variable wall thickness pipe wall thickness detection apparatus and method

Abstract

The present application relates to the technical field of pipe wall thickness detection, and particularly relates to a variable-thickness pipe wall thickness detection device and method, which comprises a variable-thickness pipe wall thickness detection device, a ring measurement unit and a point measurement unit are arranged in the detection device and are in a state of extrusion with the inner wall of a straight pipe and move at a constant speed, so that when passing through the thickened part of the straight pipe, greater pressure is received, and then reflected on the internal air pressure, and the position and thickness of the thickened part are judged by comparing the image air pressure change curve with the standard curve. The pressure wheel is provided with multiple pressure wheels, and the consistency of the air pressure change in different air pressure cylinders can be used to judge whether the thickness of the same ring surface of the inner wall of the straight pipe is uniform. The time difference of the wave peak reflected in the air pressure curve by the distance between the ring measurement unit and the point measurement unit can improve the judgment of the accuracy of the detection result by comparing the actual and theoretical values.

Description

Technical Field

[0001] This invention relates to the field of pipe wall thickness detection technology, and in particular to a device and method for detecting the wall thickness of variable thickness pipes. Background Technology

[0002] Variable thickness tubing is a new type of lightweight structural component widely used in automotive manufacturing, aerospace, and rail transportation. The thickness of variable thickness tubing is not uniform; instead, it allows for optimized material configuration based on stress distribution. Thicker sections are formed where stress is higher, while thinner sections are formed, thus effectively reducing the weight of the component while still meeting structural strength requirements.

[0003] Therefore, it is crucial to accurately detect the thickness increase location of variable-thickness pipes and whether the thickness variation meets the requirements. Currently used detection methods such as laser thickness measurement, ultrasonic thickness measurement, or radiographic thickness measurement all have significant limitations.

[0004] Laser thickness measurement can only detect changes in the outer thickness of pipes, but most variable-thickness pipes are thickened on their inner walls. Ultrasonic or X-ray thickness measurement only detects the thickness at a localized location near the probe, and cannot detect the overall thickness change of variable-thickness pipes. To obtain the overall internal condition of a variable-thickness pipe, it is necessary to perform multi-point scanning by moving the probe or the pipe, ensuring that the multi-point scans cover the entire pipe. Finally, the results of multiple scans are combined and analyzed to obtain the overall thickness change of the variable-thickness pipe. This entire process is not only cumbersome and time-consuming, but also occupies the thickness measurement equipment for an extended period. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a device and method for detecting the wall thickness of variable thickness pipes, so as to solve the technical problem that the detection of the wall thickness of variable thickness pipes in the prior art requires multiple scanning and multiple detections at multiple points.

[0006] To achieve the above objectives, the present invention provides a pipe wall thickness detection device for variable thickness pipes, including a fixing ring for fixing a straight pipe, and the detection device further includes:

[0007] The ring measurement unit has an outer ring airbag, and a barometer is installed inside the airbag.

[0008] The point measurement unit includes a rotating ring and a pressure roller that contacts the inner wall of a straight tube. A pneumatic cylinder is fixedly connected to the rotating ring. The pressure roller is rotatably connected to the outer end of a telescopic rod. The inner end of the telescopic rod is slidably connected to the pneumatic cylinder via a piston. A pneumatic sensor is also provided inside the pneumatic cylinder. The point measurement unit also includes a driving component for driving the rotating ring to rotate.

[0009] A linear motor, wherein the central axis of the output shaft of the linear motor is collinear with the central axis of the fixed straight tube, and a connecting tube is fixedly connected to the center position of the ring measurement unit and the point measurement unit, and the connecting tube is fixedly connected to the output shaft of the linear motor.

[0010] Furthermore, the connecting pipe is provided with an air supply pipe that communicates with the annular airbag and the air pressure cylinder. The other end of the air supply pipe is connected to an external air source. The connecting pipe is also provided with a cable that is connected to the driving component. The other end of the cable is connected to an external power source. The barometer and the air pressure sensor are both connected to an external data processing unit wirelessly.

[0011] Furthermore, the ring measuring unit also includes a fixed ring mounting base and a fixed ring. The fixed ring is fixedly connected to the connecting pipe through the fixed ring mounting base, and a vent valve, which is a solenoid valve, is provided between the fixed ring and the fixed ring mounting base.

[0012] The annular airbag is fixedly connected to the outer ring of the fixed ring, and the inner cavity of the annular airbag is connected to the air supply pipe through the air valve.

[0013] Furthermore, the point measurement unit also includes a rotating ring mounting base, the rotating ring is rotatably connected to the rotating ring mounting base, and the driving component is fixedly connected to the rotating ring mounting base;

[0014] The bottom of the air cylinder is provided with a self-sealing air nozzle, and the moving ring mounting base is provided with a split air valve that is connected to the self-sealing air nozzle. The split air valve is connected to the air supply pipe.

[0015] The pressure roller, telescopic rod and pneumatic cylinder are provided in multiple sets. The split-type air valve is also provided in multiple sets and corresponds to the pneumatic cylinder one by one. Each split-type air valve is connected to an air supply pipe, and each air supply pipe is provided with a solenoid valve.

[0016] Furthermore, the split-type air valve includes a drive chamber, a fixed tube, and a telescopic tube. The telescopic tube is slidably connected inside the fixed tube, and extends out of the fixed tube and is inserted into the self-sealing air nozzle to achieve connection.

[0017] The telescopic tube has a vent hole on its side wall, and the air supply tube is connected to the side wall of the fixed tube.

[0018] The drive chamber is fixedly connected to the moving ring mounting base, and an electromagnetic coil is provided inside the drive chamber. A sliding connecting rod is fixedly connected to the bottom of the telescopic tube. The lower end of the sliding connecting rod passes through the electromagnetic coil and is fixedly connected to a metal disc. A spring is provided between the electromagnetic coil and the metal disc.

[0019] The testing method using the above-mentioned testing equipment includes the following steps:

[0020] Step 1: Preparation for Testing

[0021] Randomly sample from the same batch of straight tubes, fix the sample straight tubes with a fixing ring, then place the ring measurement unit and the point measurement unit inside the front end of the sample straight tube, inflate the annular airbag and the air pressure cylinder, and make the internal air pressure of the two reach the static standard value.

[0022] Step 2: Dynamic Detection

[0023] The linear motor drives the ring measurement unit and the point measurement unit to pass through the sample straight tube, and continuously samples the entire process through the barometer and the barometer sensor and displays the waveform of the sampled data.

[0024] Step 3: Standard Comparison

[0025] The pressure change curve obtained in step two is compared with the standard pressure change curve template. The waveform consistency assessment is used to determine whether the location and magnitude of the wall thickness change in the sample straight tube meet the standard.

[0026] Furthermore, the method for pre-producing the static standard value of air pressure and the standard air pressure change curve template is as follows:

[0027] S1. Select a straight pipe that meets the standard, and place the ring measurement unit and the point measurement unit inside one end of the straight pipe;

[0028] S2. Inflate the annular airbag and air cylinder until the annular airbag and pressure roller abut against the inner wall of the straight pipe and generate pressure. Record the air pressure in the annular airbag and air cylinder under this state using a barometer and air pressure sensor, and set it as a static standard value.

[0029] S3. The linear motor drives the ring measurement unit and the point measurement unit to move in the straight tube until the ring measurement unit and the point measurement unit leave from the other end of the straight tube. The barometer and the barometer sensor continuously sample the entire process and display the waveform of the sampled data.

[0030] S4. Conduct multiple experiments to obtain the average trend, and finally create a standard air pressure change curve template and save it.

[0031] Furthermore, the static standard value of absolute air pressure inside the annular airbag is set between 145-155 kPa, the static standard value of absolute air pressure inside the air cylinder is set between 155-165 kPa, the annular measuring unit and the point measuring unit move at a uniform speed in the straight tube, the moving speed is set between 200-400 mm / s, and the distance between the annular measuring unit and the point measuring unit is set between 50-150 mm.

[0032] Furthermore, by dividing the distance between the ring measurement unit and the point measurement unit by their moving speed in the straight pipe, the theoretical time difference between the peaks in their pressure change curves is obtained.

[0033] The actual time difference between the peaks in the pressure change curves of the two devices is obtained by using the detection results of the loop measurement unit and the point measurement unit in step two.

[0034] The difference between the actual time difference and the theoretical time difference is calculated to further verify the accuracy of the test results.

[0035] Furthermore, in step two, the data sampled by the air pressure sensors in different air pressure cylinders are displayed as data waveforms, and the thickness of the same annular surface of the inner wall of the sample straight tube is judged by waveform consistency evaluation.

[0036] The beneficial effects of the present invention are as follows: 1. The ring measuring unit and the point measuring unit are set to be in a state of compression with the inner wall of the straight pipe and move at a constant speed. Therefore, when passing through the thickened part of the straight pipe, it will be subjected to greater pressure, which will be reflected in the internal air pressure. The position and thickness of the thickened part can be judged by comparing the imaged air pressure change curve with the standard curve.

[0037] 2. Multiple pressure rollers are set up. By observing the consistency of air pressure changes in different air cylinders, it is possible to determine whether the thickness of the same annular surface of the straight pipe inner wall is uniform.

[0038] 3. By utilizing the time difference between the peaks in the pressure curve reflected by the distance between the ring measurement unit and the point measurement unit, the accuracy of the test results can be improved through comparison between actual and theoretical results. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of the detection method of the present invention.

[0041] Figure 2 This is a flowchart of the standard setting method of the present invention.

[0042] Figure 3 This is a schematic diagram of the overall structure and principle of the device of the present invention.

[0043] Figure 4 This is a schematic diagram of the structure of the ring measurement unit and the point measurement unit in the device of the present invention.

[0044] Figure 5 This is a schematic diagram of the ring measurement unit and the point measurement unit in the device of the present invention from another perspective.

[0045] Figure 6This is a schematic diagram of the internal structure of the point measurement unit in the device of the present invention.

[0046] Figure 7 This is a schematic diagram of the internal structure of the split-type air valve in the device of the present invention.

[0047] Figure 8 This is a sample diagram of the air pressure change curve within the ring measurement unit during the detection process of this invention.

[0048] Figure 9 This is a sample diagram of the air pressure change curve within the point measurement unit during the detection process of this invention.

[0049] The diagram is marked as follows:

[0050] 10. Linear motor; 11. Fixed ring clamp; 12. Straight pipe; 13. Thickened section; 14. Connecting pipe; 15. Ring measuring unit; 16. Point measuring unit; 17. Cable; 18. Air supply pipe; 101. Fixed ring mounting base; 102. Fixed ring; 103. Annular airbag; 104. Vent valve; 105. Barometer; 111. Moving ring mounting base; 112. Driving component; 113. Rotating ring; 114. Air cylinder; 115. Telescopic rod; 116. Bracket; 117. Pressure roller; 118. Piston; 119. Self-sealing air nozzle; 120. Split-type air valve; 121. Drive chamber; 122. Fixed pipe; 123. Telescopic pipe; 124. Connecting port; 125. Vent hole; 126. Sliding connecting rod; 127. Metal disc; 128. Electromagnetic coil; 129. Air pressure sensor. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0052] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0053] The first aspect of the invention, as Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, ultrasonic thickness measurement and radiographic thickness measurement only detect the local thickness at the probe location, making it difficult to detect the overall thickness change of variable-thickness pipes. Furthermore, ultrasonic and radiographic thickness gauges are expensive and cumbersome to use. Therefore, this invention designs a novel method for detecting the wall thickness of variable-thickness pipes, enabling a convenient and quick approximate assessment of the overall wall thickness variation. A corresponding device for detecting the wall thickness of variable-thickness pipes is also designed.

[0054] The core of the device consists of a ring measurement unit 15 and a point measurement unit 16. The outer ring of the ring measurement unit 15 is an annular airbag 103, and a barometer 105 is installed inside the annular airbag 103. The point measurement unit 16 includes a rotating ring 113 and a pressure roller 117 that contacts the inner wall of the straight pipe 12. A pressure cylinder 114 is fixedly connected to the rotating ring 113. The pressure roller 117 is rotatably connected to the outer end of the telescopic rod 115. The inner end of the telescopic rod 115 is slidably connected to the pressure cylinder 114 through a piston 118. A pressure sensor 129 is also installed inside the pressure cylinder 114. The point measurement unit 16 also includes a drive component 112 for driving the rotating ring 113 to rotate.

[0055] Therefore, the ring measuring unit 15 and the point measuring unit 16 are designed to be in a state of compression with the inner wall of the straight tube 12 and move at a constant speed. When the ring measuring unit 15 and the point measuring unit 16 pass through the thickened part 13 of the straight tube 12, they will be subjected to greater pressure, which will be reflected in the internal air pressure. By comparing the imaged air pressure change curve with the standard curve, it can be determined whether the position and thickness of the thickened part 13 meet the standard.

[0056] In addition, a linear motor 10 and a fixing ring 11 for fixing the straight pipe 12 are provided, with the central axis of the output shaft of the linear motor 10 collinear with the central axis of the fixed straight pipe 12. A connecting pipe 14 is fixedly connected to the center position of the ring measuring unit 15 and the point measuring unit 16, and the connecting pipe 14 is fixedly connected to the output shaft of the linear motor 10. This ensures that the ring measuring unit 15 and the point measuring unit 16 remain stable during movement, and guarantees that the ring measuring unit 15 and the point measuring unit 16 experience uniform force at various local positions on the inner wall of the straight pipe 12.

[0057] The ring measurement unit 15 also includes a fixed ring mounting base 101 and a fixed ring 102. The fixed ring 102 is fixedly connected to the connecting pipe 14 through the fixed ring mounting base 101, and a vent valve 104 is provided between the fixed ring 102 and the fixed ring mounting base 101. The vent valve 104 is a solenoid valve. The annular airbag 103 is fixedly connected to the outer ring of the fixed ring 102, and the inner cavity of the annular airbag 103 is connected to the air supply pipe 18 through the vent valve 104.

[0058] The point measurement unit 16 also includes a rotating ring mounting base 111, a rotating ring 113 rotatably connected to the rotating ring mounting base 111, and a driving component 112 fixedly connected to the rotating ring mounting base 111. The bottom of the air cylinder 114 is provided with a self-sealing nozzle 119, and the rotating ring mounting base 111 is provided with a split-type air valve 120 that mates with the self-sealing nozzle 119. The split-type air valve 120 is connected to the air supply pipe 18.

[0059] Multiple sets of pressure rollers 117, telescopic rods 115 and pneumatic cylinders 114 are provided. Multiple split-type air valves 120 are also provided and correspond one-to-one with the pneumatic cylinders 114. Each split-type air valve 120 is connected to an air supply pipe 18, and each air supply pipe 18 is equipped with a solenoid valve.

[0060] Correspondingly, the connecting pipe 14 contains air supply pipes 18 that communicate with the annular airbag 103 and the air cylinder 114. Multiple air supply pipes 18 are provided, one of which communicates with the annular airbag 103, while the others are connected to the air cylinder 114 via separate air valves 120. The other end of all air supply pipes 18 is connected to an external air source. The connecting pipe 14 also contains a cable 17 that connects to the drive unit 112, with the other end of the cable 17 connected to an external power source. The barometer 105 and the pressure sensor 129 are both wirelessly connected to an external data processing unit.

[0061] When using the testing equipment to detect pipe wall thickness, both the barometer 105 and the pressure sensor 129 transmit sampling data to the external data processing unit in real time.

[0062] Therefore, when inflating (or deflating) the annular airbag 103 and the air cylinder 114, the pressure is controlled separately by the solenoid valve on each air supply pipe 18 to ensure that the air pressure in the annular airbag 103 and each air cylinder 114 can be precisely controlled.

[0063] Preferably, the air pressure in each air cylinder 114 should be kept consistent.

[0064] The split-type air valve 120 can be connected and disconnected with the self-sealing air nozzle 119. The split-type air valve 120 includes a drive chamber 121, a fixed tube 122, and a telescopic tube 123. The telescopic tube 123 is slidably connected inside the fixed tube 122 and extends out of the fixed tube 122 to be inserted into the self-sealing air nozzle 119 for connection. A vent hole 125 is provided on the side wall of the telescopic tube 123, and the air supply pipe 18 is connected to the side wall of the fixed tube 122. The drive chamber 121 is fixedly connected inside the dynamic ring mounting base 111, and an electromagnetic coil 128 is provided inside the drive chamber 121. A sliding connecting rod 126 is fixedly connected to the bottom of the telescopic tube 123. The lower end of the sliding connecting rod 126 passes through the electromagnetic coil 128 and is fixedly connected to a metal disc 127, and a spring is provided between the electromagnetic coil 128 and the metal disc 127.

[0065] The electromagnetic coil 128 is also connected to the cable 17 and is powered through the cable 17.

[0066] When the air cylinder 114 needs to be charged or depressurized, the electromagnetic coil 128 is energized to generate a magnetic force, which attracts the metal disc 127 to move. This, in turn, moves the telescopic tube 123 via the sliding connecting rod 126, causing the telescopic tube 123 to extend from the fixed tube 122 and be inserted into the self-sealing nozzle 119 to achieve connection.

[0067] Additionally, a vent hole 125 is provided on the side wall of the telescopic tube 123, and the air supply tube 18 is connected to the side wall of the fixed tube 122, with the connection point being the connection port 124. When the metal disc 127 moves to its limit position, that is, when the sliding connecting rod 126 extends to its full position, the vent hole 125 and the connection port 124 can coincide, thereby realizing the connection of the air passage of the air cylinder 114.

[0068] The self-sealing nozzle 119 adopts a design similar to a balloon nozzle. When the electromagnetic coil 128 is de-energized, the spring drives the metal disc 127 to reset, that is, when the telescopic tube 123 is pulled out from the self-sealing nozzle 119, the self-sealing nozzle 119 can automatically close.

[0069] Overall, the detection equipment designed in this invention has a much lower manufacturing and operating cost than ultrasonic thickness gauges and X-ray thickness gauges. Specific Implementation

[0070] like Figure 1 , Figure 2 , Figure 3 , Figure 8 and Figure 9 As shown, a thickness measurement method is designed using the aforementioned detection equipment.

[0071] First, select a standard straight tube 12. Select multiple straight tubes 12 from the finished products, and then use an ultrasonic thickness gauge or a radiographic thickness gauge to perform multi-point scanning inspection on the multiple straight tubes 12 until the entire straight tube 12 is covered. This will give a clear result of the overall thickness change of the multiple straight tubes 12. Based on the inspection results, select the one that best meets the standard from the multiple straight tubes 12 as the standard straight tube 12.

[0072] Although it is very tedious to perform full-coverage inspection of multiple straight pipes 12 using an ultrasonic thickness gauge or a radiographic thickness gauge, it is a once-and-for-all task and therefore very necessary. The number of straight pipes 12 to be inspected should be as large as possible.

[0073] After selecting the standard straight pipe 12, the standard straight pipe 12 is subjected to multiple thickness measurement tests using the testing equipment designed in this invention. The average trend is obtained, and finally a standard air pressure change curve template is made and stored.

[0074] Specifically, when it is time to conduct sampling inspections on the subsequently produced straight pipes 12.

[0075] First, random samples are taken from the same batch of straight tubes 12. The sample straight tubes 12 are fixed by the fixing ring 11. Then, the ring measuring unit 15 and the point measuring unit 16 are placed inside the front end of the sample straight tubes 12. The annular airbag 103 and the air pressure cylinder 114 are inflated so that the internal air pressure of the two reaches the static standard value.

[0076] After preparation, the linear motor 10 drives the ring measuring unit 15 and the point measuring unit 16 through the sample straight tube 12, continuously sampling the entire process through the barometer 105 and the pressure sensor 129, displaying the sampled data waveforms, and obtaining two sets of pressure change curves, such as... Figure 8 and Figure 9 As shown.

[0077] The obtained pressure change curve is compared with the standard pressure change curve template. The waveform consistency evaluation is used to determine whether the position and magnitude of the wall thickness change of the sample straight tube 12 meet the standard.

[0078] The static standard value of absolute air pressure inside the annular airbag 103 is set between 145-155 kPa, the static standard value of absolute air pressure inside the air pressure cylinder 114 is set between 155-165 kPa, the annular measuring unit 15 and the point measuring unit 16 move at a constant speed in the straight pipe 12, the moving speed is set between 200-400 mm / s, and the distance between the annular measuring unit 15 and the point measuring unit 16 is set between 50-150 mm.

[0079] Since the point measurement unit 16 is in front of the ring measurement unit 15, their positions are different at the same time point, and the point measurement unit 16 must reach the thickened part 13 first. This means that in the data curves sampled by the barometer 105 and the pressure sensor 129, the latter must appear with a peak first. Therefore, dividing the distance between the ring measurement unit 15 and the point measurement unit 16 by their moving speeds within the straight pipe 12 yields the theoretical time difference between the peaks in their pressure change curves.

[0080] Therefore, to make the detection results more accurate, the actual time difference between the peaks in the pressure change curves of the ring measurement unit 15 and the point measurement unit 16 is obtained from their detection results. Calculating the difference between the actual time difference and the theoretical time difference can be used to further verify the accuracy of the detection results, thereby improving the judgment of the accuracy of the detection results.

[0081] Preferably, since multiple pressure rollers 117 are provided, and the multiple pressure rollers 117 are located on the outer ring of the point measurement unit 16 and arranged at equal angles, the multiple pressure rollers 117 simultaneously contact different positions on the same annular surface of the inner wall of the straight pipe 12.

[0082] Therefore, by displaying the data sampled by the air pressure sensor 129 in different air pressure cylinders 114 as data waveforms, and by evaluating the waveform consistency, it is possible to determine whether the thickness of the same annular surface of the inner wall of the sample straight tube 12 is uniform.

[0083] The method for making the static standard value of air pressure and the standard air pressure change curve template mentioned in the thickness measurement method of this invention is the same as the principle of the thickness measurement method.

[0084] First, install the selected standard straight pipe 12, and then place the ring measuring unit 15 and the point measuring unit 16 inside one end of the straight pipe 12.

[0085] Then, the annular airbag 103 and the air cylinder 114 are inflated until the annular airbag 103 and the pressure roller 117 abut against the inner wall of the straight tube 12 and generate pressure. The air pressure in the annular airbag 103 and the air cylinder 114 under this state is recorded by the barometer 105 and the air pressure sensor 129, and this air pressure is set as the static standard value.

[0086] After the equipment has finished working, the linear motor 10 drives the ring measurement unit 15 and the point measurement unit 16 to move in the straight pipe 12 until the ring measurement unit 15 and the point measurement unit 16 leave from the other end of the straight pipe 12. The entire process is continuously sampled by the barometer 105 and the barometer 129 and the waveform of the sampled data is displayed.

[0087] A single experiment may produce significant errors, so multiple experiments are required. The average trend of the results from multiple experiments is then calculated to create a standard pressure change curve template.

[0088] Overall, the thickness measurement method of the present invention, although sacrificing some accuracy compared to the original ultrasonic or radiographic thickness measurement, can quickly make a rough assessment of the overall wall thickness variation of variable thickness pipes, and is very efficient.

[0089] Therefore, when it is necessary to measure the wall thickness at key points of pipes with varying thicknesses, it is still recommended to use a high-precision thickness gauge (EMAT is recommended here, as the accuracy of radiographic thickness measurement is easily affected by other factors). However, when it is necessary to detect the overall thickness variation of straight pipe 12, the thickness measurement method designed in this invention can be used, which is fast and convenient, especially suitable for multi-round sampling inspections. The results of multi-round sampling inspections can provide important references for the quality assessment of the same batch of products.

[0090] In summary, this invention sets the ring measuring unit 15 and the point measuring unit 16 to be under compression and move at a constant speed against the inner wall of the straight tube 12. Therefore, when passing through the thickened portion 13 of the straight tube 12, it will be subjected to greater pressure, which will be reflected in the internal air pressure. By comparing the imaged air pressure change curve with a standard curve, the wall thickness of the straight tube 12 can be determined, especially the position and thickness of the thickened portion 13. Furthermore, multiple pressure rollers 117 are provided, and the consistency of air pressure changes in different air pressure cylinders 114 can be used to determine whether the thickness of the same annular surface of the inner wall of the straight tube 12 is uniform.

[0091] By utilizing the time difference between the peaks in the pressure curve reflected by the distance between the ring measurement unit 15 and the point measurement unit 16, the accuracy of the test results can be improved through comparison between actual and theoretical results.

[0092] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A pipe wall thickness detection device for variable thickness pipes, comprising a fixing ring (11) for fixing a straight pipe (12), characterized in that, The detection equipment also includes: The ring measurement unit (15) has an outer ring of an annular airbag (103) and a barometer (105) inside the annular airbag (103). The point measurement unit (16) includes a rotating ring (113) and a pressure roller (117) that contacts the inner wall of the straight tube (12). A pneumatic cylinder (114) is fixedly connected to the rotating ring (113). The pressure roller (117) is rotatably connected to the outer end of the telescopic rod (115). The inner end of the telescopic rod (115) is slidably connected to the pneumatic cylinder (114) through a piston (118). A pneumatic sensor (129) is also provided in the pneumatic cylinder (114). The point measurement unit (16) is also provided with a driving component (112) for driving the rotating ring (113) to rotate. A linear motor (10) has its output shaft's central axis collinear with the central axis of a fixed straight tube (12). A connecting tube (14) is fixedly connected to the center of the ring measuring unit (15) and the point measuring unit (16). The connecting tube (14) is fixedly connected to the output shaft of the linear motor (10).

2. The variable thickness pipe wall thickness detection device according to claim 1, characterized in that, The connecting pipe (14) is provided with multiple air supply pipes (18) that are connected to the annular airbag (103) and the air cylinder (114). The other end of the air supply pipe (18) is connected to an external air source. The connecting pipe (14) is also provided with a cable (17) that is connected to the drive unit (112). The other end of the cable (17) is connected to an external power source. The barometer (105) and the air pressure sensor (129) are both connected to an external data processing unit wirelessly.

3. The variable thickness pipe wall thickness detection device according to claim 2, characterized in that, The ring measuring unit (15) further includes a fixed ring mounting base (101) and a fixed ring (102). The fixed ring (102) is fixedly connected to the connecting pipe (14) through the fixed ring mounting base (101), and a vent valve (104) is provided between the fixed ring (102) and the fixed ring mounting base (101). The vent valve (104) is a solenoid valve. The annular airbag (103) is fixedly connected to the outer ring of the fixed ring (102), and the inner cavity of the annular airbag (103) is connected to the air supply pipe (18) through the air valve (104).

4. The pipe wall thickness detection device for variable thickness pipes according to claim 2, characterized in that, The point measurement unit (16) also includes a rotating ring mounting base (111), the rotating ring (113) is rotatably connected to the rotating ring mounting base (111), and the driving component (112) is fixedly connected to the rotating ring mounting base (111); The bottom of the air cylinder (114) is provided with a self-sealing air nozzle (119), and the rotating ring mounting base (111) is provided with a split air valve (120) that is connected to the self-sealing air nozzle (119). The split air valve (120) is connected to the air supply pipe (18). The pressure roller (117), telescopic rod (115) and air cylinder (114) are provided in multiple sets. The split air valve (120) is also provided in multiple sets and corresponds one-to-one with the air cylinder (114). Each split air valve (120) is connected to an air supply pipe (18), and each air supply pipe (18) is provided with a solenoid valve.

5. The variable thickness pipe wall thickness detection device according to claim 4, characterized in that, The split-type air valve (120) includes a drive chamber (121), a fixed tube (122) and a telescopic tube (123). The telescopic tube (123) is slidably connected inside the fixed tube (122). The telescopic tube (123) extends out of the fixed tube (122) and is inserted into the self-sealing air nozzle (119) to achieve connection. The telescopic tube (123) has a vent hole (125) on its side wall, and the air supply tube (18) is connected to the side wall of the fixed tube (122). The drive chamber (121) is fixedly connected to the moving ring mounting base (111), and an electromagnetic coil (128) is provided in the drive chamber (121). A sliding connecting rod (126) is fixedly connected to the bottom of the telescopic tube (123). The lower end of the sliding connecting rod (126) passes through the electromagnetic coil (128) and is fixedly connected to a metal disc (127). A spring is provided between the electromagnetic coil (128) and the metal disc (127).

6. A detection method using the detection equipment described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Preparation for Testing Randomly sample from the same batch of straight tubes (12), fix the sample straight tube (12) with a fixing ring (11), then place the ring measurement unit (15) and the point measurement unit (16) inside the front end of the sample straight tube (12), inflate the annular airbag (103) and the air cylinder (114) so ​​that the internal air pressure of the two reaches the static standard value; Step 2: Dynamic Detection A linear motor (10) drives a ring measuring unit (15) and a point measuring unit (16) through the sample straight tube (12), and continuously samples the entire process through a barometer (105) and a pressure sensor (129) and displays the waveform of the sampled data. Step 3: Standard Comparison The pressure change curve obtained in step two is compared with the standard pressure change curve template. The waveform consistency evaluation is used to determine whether the position and magnitude of the wall thickness change of the sample straight tube (12) meet the standard.

7. The method for detecting the wall thickness of a variable thickness pipe according to claim 6, characterized in that, The method for pre-producing the static standard value of air pressure and the standard air pressure change curve template is as follows: S1. Select a straight pipe (12) that meets the standard, and place the ring measurement unit (15) and the point measurement unit (16) inside one end of the straight pipe (12); S2. Inflate the annular airbag (103) and the air cylinder (114) until the annular airbag (103) and the pressure roller (117) abut against the inner wall of the straight tube (12) and generate pressure. Record the air pressure in the annular airbag (103) and the air cylinder (114) under this state by the barometer (105) and the air pressure sensor (129) and set it as the static standard value. S3. The linear motor (10) drives the ring measurement unit (15) and the point measurement unit (16) to move in the straight tube (12) until the ring measurement unit (15) and the point measurement unit (16) leave from the other end of the straight tube (12). The barometer (105) and the barometer (129) continuously sample the entire process and display the waveform of the sampled data. S4. Conduct multiple experiments to obtain the average trend, and finally create a standard air pressure change curve template and save it.

8. The method for detecting the wall thickness of a variable thickness pipe according to claim 6, characterized in that, The static standard value of absolute air pressure inside the annular airbag (103) is set between 145-155 kPa, the static standard value of absolute air pressure inside the air pressure cylinder (114) is set between 155-165 kPa, the annular measuring unit (15) and the point measuring unit (16) move at a constant speed in the straight pipe (12), the moving speed is set between 200-400 mm / s, and the distance between the annular measuring unit (15) and the point measuring unit (16) is set between 50-150 mm.

9. The method for detecting the wall thickness of a variable thickness pipe according to claim 8, characterized in that, Divide the distance between the ring measurement unit (15) and the point measurement unit (16) by their moving speed in the straight pipe (12) to obtain the theoretical time difference between the peaks in their pressure change curves; The actual time difference between the peaks in the pressure change curves of the two devices is obtained by using the detection results of the ring measurement unit (15) and the point measurement unit (16) in step two. The difference between the actual time difference and the theoretical time difference is calculated to further verify the accuracy of the test results.

10. The method for detecting the wall thickness of a variable thickness pipe according to claim 6, characterized in that, In step two, the data sampled by the air pressure sensor (129) in different air pressure cylinders (114) are displayed as data waveforms, and the thickness of the same annular surface of the inner wall of the sample straight tube (12) is judged by waveform consistency evaluation.

Images