CN109341553B - A kind of measuring device and measuring method of pipe wall thickness - Google Patents

Abstract

The invention discloses a pipe wall thickness measuring device, comprising a fixed bracket for fixing a pipe to be measured, a rotating bracket, a first distance sensor and a second distance sensor, and a processor; the rotating bracket can drive the first distance sensor and the second distance sensor. Two distance sensors rotate around the central axis of rotation, the first distance sensor measures the first distance from the inner wall of the pipe, and the second distance sensor measures the second distance from multiple points on the outer wall of the pipe; the processor measures the first distance and The second distance obtains the thickness of the pipe wall. The measuring device in the present invention can perform non-contact measurement on the pipe wall, avoiding the interference caused by the frictional resistance of the distance sensor in the process of rotating measurement; it can be widely used in the measurement of metal, plastic and other opaque materials. It has a simple structure, is easy to install, and can quickly and accurately measure the thickness of the pipe. The present invention also provides a method for measuring the pipe wall of a pipe, which has the above beneficial effects.

Description

A kind of measuring device and measuring method of pipe wall thickness

technical field

The invention relates to the technical field of pipe quality detection, in particular to a pipe wall thickness measurement device and a pipe wall thickness measurement method.

Background technique

In the construction industry, it is often necessary to measure the thickness of the pipe wall of the pipe structure. The most widely used wall thickness detection method is the contact measurement method using automatic/manual nozzle bayonet measurement. This measurement method is mainly composed of a fixed bracket, a rotating bracket, a jaw-type bayonet and a measuring sensor; the fixed bracket directly fixes the nozzle, the bayonet installed on the rotating bracket directly clamps the pipe wall, and then the rotating bracket drives the clamp The mouth rotates once along the pipe wall, and the actual wall thickness measurement is completed by a dial indicator or other position/pressure sensor (such as the utility model patent of publication number CN205607357U or CN203550860U, which is one of the forms of bayonet).

The common non-contact wall thickness measurement methods include pulsed eddy current measurement, ultrasonic detection, and laser refraction. Among them, pulsed eddy current and ultrasonic detection are often used for thickness detection of metal materials. The laser refraction method is used to measure and calculate the angle change after two refractions by photoelectric inorganic generators, reflectors, receivers, etc., so as to measure the wall thickness, but it is only used for inorganic materials such as transparent or translucent glass (such as the publication number It is the invention patent of CN106017340A). The ultrasonic testing method can be used for the wall thickness of plastic pipes, but on the one hand, the ultrasonic testing method needs to clean the pipe surface and apply couplant, which is cumbersome to operate. On the other hand, the ultrasonic detection measurement and reading are relatively slow, and the detection time is long (for the ultrasonic detection method, please refer to the invalid patent publication number CN103134449A).

It can be seen that the current methods for measuring pipes have certain limitations, and the testing devices are complicated and costly.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a pipe wall thickness measurement device and a pipe wall thickness measurement method, which solve the problems of limitations and high testing costs in the current pipe wall thickness measurement.

In order to solve the above technical problems, the present invention provides a pipe wall thickness measurement device, including a fixed bracket for fixing the pipe to be measured, a rotating bracket, a first distance sensor and a second distance sensor arranged on the rotating bracket, and processor;

Wherein, the rotating bracket can drive the first distance sensor and the second distance sensor to rotate around a central axis of rotation, and the central axis of rotation is parallel to the central axis of the pipe, and the central axis of rotation is parallel to the central axis of the pipe. The distance between the central axes of the pipes is smaller than the inner diameter of the pipes;

The first measurement direction of the first distance sensor points to the inner wall of the pipe and is not parallel to the rotation center axis, and the first measurement direction can be changed with the rotation of the first distance sensor, so that the first A distance sensor measures the first distance with a plurality of position points on the inner wall of the pipe;

The second measurement direction of the second distance sensor points to the outer wall of the pipe and is not parallel to the rotation center axis, and the second measurement direction can be changed with the rotation of the second distance sensor, so that the first Two second distances between the distance sensor and a plurality of position points on the outer wall of the pipe;

The processor is connected to the first distance sensor and the second distance sensor, and obtains the thickness of the pipe wall according to the first distance and the second distance.

Wherein, the first distance sensor and the second distance sensor are both laser sensors;

Wherein, the distance of the first distance sensor and the second distance sensor relative to the rotation center axis on the rotating support is adjustable, and the measurement directions of the first distance sensor and the second distance sensor are both Adjustable.

Wherein, the first distance sensor, the second distance sensor and the rotation center axis are located in the same plane, and the first distance sensor and the second distance sensor are located on both sides of the rotation center axis, respectively.

Wherein, the rotating support is also provided with a distance measuring device for measuring the distance between the first distance sensor and the second distance sensor and the rotation center axis respectively.

The present invention also provides a method for measuring the thickness of the pipe wall, using the device for measuring the thickness of the pipe wall described in any one of the above, including:

The angle parameters and distance parameters of the first distance sensor and the second distance sensor are obtained in advance, and the pipes to be measured are fixed on a fixed bracket; wherein, the angle parameters include the first distance sensor and the second distance sensor. the angle between the measurement directions of the distance sensors and the rotation center axis, respectively, and the distance parameter is the distance between the first distance sensor and the second distance sensor and the rotation center axis;

Controlling the rotating bracket to drive the first distance sensor and the second distance sensor to rotate with the rotation center axis;

obtaining a plurality of first distances measured when the first distance sensor rotates and a plurality of second distances measured when the second distance sensor rotates;

The pipe wall thickness of the pipe material is obtained according to a plurality of the first distances and a plurality of the second distances, the angle parameter and the distance parameter.

Wherein, the step of measuring the first distance by the first distance sensor includes:

Each time the rotating bracket drives the first distance sensor to rotate by a preset angle, the first distance sensor measures a first distance between a group of the first distance sensors and the inner wall of the pipe;

Each time the rotating bracket drives the second distance sensor to rotate by a preset angle, the first distance sensor measures a second distance between a group of the second distance sensors and the inner wall of the pipe.

Wherein, the obtaining the thickness of the pipe wall of the pipe material according to the first distance and the second distance includes:

According to each set of the first distance and the corresponding rotation angle, the polar coordinates (d ₁ +ρ _n sinα ₁ , θ _n ) of the inner diameter circle of the pipe can be obtained, where d ₁ is the distance of the first distance sensor parameter, ρ _n is the first distance of the nth group, α ₁ is the angle parameter of the first distance sensor, and θ _n is the rotation angle corresponding to the nth group of the first distance;

According to each set of the second distance and the corresponding rotation angle, the polar coordinates (d ₂ -rn sinα ₂ , θ _n ) of the outer diameter circle of the pipe can be obtained, _where d ₂ is the first distance sensor distance parameter, rn is the second distance of the _nth group, α2 is the angle parameter of the _second distance sensor, _θn is the rotation angle corresponding to the nth group of the second distance, and n is a positive integer;

According to the polar coordinates of the inner diameter circle (d ₁ +ρ _n sinα ₁ , θ _n ) and the polar coordinates of the outer diameter circle (d ₂ -rn sinα ₂ , θ _n ), the inner diameter of the pipe _is obtained by fitting circle and outer diameter circle;

According to the radius of the inner diameter circle and the outer diameter circle, the pipe wall thickness of the pipe material is obtained.

Wherein, the obtaining the thickness of the pipe wall of the pipe material according to the first distance and the second distance includes:

Eliminate the abnormal first distance and second distance according to preset conditions;

selecting the largest first and second distances and the smallest first and second distances;

According to the formula D ₁ =(ρ _max +ρ _min )sinβ ₁ +2d ₁ , the diameter of the inner wall of the pipe is obtained; wherein, D ₁ is the diameter of the inner wall of the pipe, ρ _max and ρ _min are the maximum and minimum first distances, respectively, α ₁ is the angle parameter of the first distance sensor, and d ₁ is the distance parameter of the first distance sensor;

According to the formula D ₂ =(r _max +r _min )sinα ₂ -2d ₂ , the diameter of the outer wall of the pipe is obtained; wherein, D ₂ is the diameter of the outer wall of the pipe, r _max and r _min are the maximum and minimum second distances, respectively, α ₂ is the angle parameter of the second distance sensor, and d ₂ is the distance parameter of the second distance sensor;

The pipe wall thickness is obtained from the pipe inner wall diameter and the pipe outer wall diameter.

Wherein, the pre-obtaining angle parameters and distance parameters of the first distance sensor and the second distance sensor include:

Fix the first standard pipe on the fixing bracket;

Control the rotating support to rotate with the rotation center axis, obtain the maximum and minimum first distances relative to the inner wall of the first standard pipe by measuring the first distance sensor, and obtain the first distance relative to the first standard pipe measured by the second distance sensor. Describe the largest and smallest second distances from the outer wall of the first standard pipe;

Fix the second standard pipe on the fixing bracket;

Control the rotating support to rotate with the rotation center axis, obtain the maximum and minimum first distances relative to the inner wall of the second standard pipe by measuring the first distance sensor, and obtain the first distance relative to the second standard pipe measured by the second distance sensor. The largest and smallest second distances from the outer wall of the second standard pipe;

According to the maximum and minimum first distances, the maximum and minimum second distances with respect to the inner wall of the first standard pipe material, and the maximum and minimum first distances, maximum and minimum distances with respect to the inner wall of the second standard pipe material and the smallest second distance, the angle parameter and the distance parameter are obtained.

Wherein, after obtaining the pipe wall thickness of the pipe, it also includes:

It is judged whether the difference between the thickness of the pipe wall and the standard thickness is within a preset range, and if so, the pipe material is qualified, and a measurement result is output.

The pipe wall thickness measurement device provided by the present invention comprises a rotating bracket that drives the first distance sensor and the second distance sensor to rotate around a central axis of rotation, the central axis of rotation is parallel to the central axis of the pipe, and the central axis of the rotation is parallel to the central axis of the pipe. The distance between them is smaller than the inner diameter of the pipe; and the first measurement direction of the first distance sensor points to the inner wall of the pipe and is not parallel to the central axis of rotation, then the first measurement direction can be changed with the rotation of the first distance sensor. When the distance sensor rotates 360 degrees, the first distance sensor can measure the first distance with multiple positions around the inner wall of the pipe; the projection of the first distance on the plane perpendicular to the pipe is the first distance sensor Based on the distance between the processing direction of the pipe and each point around the inner wall of the pipe, based on the geometric relationship, the processor can obtain the inner diameter size of the inner wall of the pipe according to the first distance. Similarly, the second measurement direction of the second distance sensor points to the outer wall of the pipe, and the outer diameter of the pipe can be obtained in a similar manner, and then the thickness of the pipe wall can be obtained.

The measuring device in the present invention does not need to be in contact with the pipe wall when measuring the pipe wall, which avoids the problem of inaccurate measurement caused by the friction between the sensor and the pipe wall during the rotation process; The measuring device has smaller restrictions on the material of the pipe, and can be widely used in the measurement of metal, plastic and other opaque materials, and has a wider range of use; in addition, the measuring device in the present invention has a simple structure and is easy to install. It can quickly and accurately measure the thickness of the pipe.

The present invention also provides a method for measuring the pipe wall of a pipe, which has the above beneficial effects.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following will briefly introduce the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the working schematic diagram of the pipe wall thickness measuring device provided by the embodiment of the present invention;

Fig. 2 is the working schematic diagram perpendicular to the direction of the pipe material in Fig. 1;

3 is a schematic flowchart of a method for measuring the thickness of a pipe wall according to an embodiment of the present invention;

FIG. 4 is a schematic flow chart of obtaining the pipe wall thickness of a pipe provided by an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of obtaining the wall thickness of a pipe material provided by an embodiment of the present invention;

6 is a schematic flowchart of a method for obtaining the thickness of a pipe wall provided by another specific embodiment of the present invention;

FIG. 7 is a schematic diagram of an inner diameter circle and an outer diameter circle of a pipe material provided by an embodiment of the present invention;

FIG. 8 is a schematic flowchart of obtaining an angle parameter and a distance parameter according to an embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in FIG. 1 and FIG. 2 , FIG. 1 is a working schematic diagram of a pipe wall thickness measuring device provided in an embodiment of the present invention, and FIG. 2 is a working schematic diagram in a direction perpendicular to the pipe material in FIG. 1 . Specifically, the measuring device may include:

A fixed support 2 for fixing the pipe material 1 to be measured; a rotating support 3, a first distance sensor 4 and a second distance sensor 5 arranged on the rotating support 3, and a processor.

During actual measurement, as shown in FIGS. 1 and 2 , the rotating bracket 3 can drive the first distance sensor 4 and the second distance sensor 5 to rotate around the central axis of rotation, and the central axis of rotation is parallel to the central axis of the pipe 1 . That is, the first distance sensor 4 and the second distance sensor 5 rotate in a plane perpendicular to the pipe 1 . And the distance between the central axis of rotation and the central axis of the pipe material 1 is smaller than the radius of the inner wall of the pipe material 1 .

At the same time, the first measurement direction of the first distance sensor 4 points to the inner wall of the pipe 1 and is not parallel to the central axis of rotation. The first measurement direction can be changed with the rotation of the first distance sensor 4, so that the first distance sensor 4 measures The first distance between a plurality of position points on the inner wall of the pipe material 1.

Then, when the rotating bracket 3 drives the first distance sensor 4 to rotate 360 degrees, the trajectory of the distance measuring line of the first distance sensor 4 is a conical surface, and the intersection of the conical surface and the inner wall of the pipe 1 is the first distance sensor 4. Measure the measurement position point on the inner wall of the pipe 1, and the first distance is the distance value between the first distance sensor 4 and the measurement position point.

Similarly, the second measurement direction of the second distance sensor 5 points to the outer wall of the pipe 1 and is not parallel to the central axis of rotation. The second measurement direction can be changed with the rotation of the second distance sensor 5, and the second distance sensor 5 can measure Obtain the second distances between the second distance sensor 5 and multiple position points on the outer wall of the pipe 1 .

Because the angle between the measurement direction of the first distance sensor 4 and the second distance sensor 5 and the rotation center axis is fixed and measurable. Then the projected lengths of the first distance and the second distance on the plane perpendicular to the pipe material 1 can be obtained by calculation. Combining the distances between the first distance sensor 4 and the second distance sensor 5 and the rotation center axis, the inner and outer diameters of the pipe material 1 can be obtained, and finally the thickness of the pipe wall of the pipe material 1 can be obtained.

Therefore, the processor is connected to the first distance sensor 4 and the second distance sensor 5, and obtains the thickness of the pipe wall of the pipe material 1 according to the first distance and the second distance.

The processor is connected with the first distance sensor 4 and the second distance sensor 5 to obtain the data of the first distance and the second distance, and the wall thickness of the pipe material 1 can be obtained according to a preset calculation program.

In this embodiment, as shown in FIG. 2 , the two dotted circles in FIG. 2 represent the motion trajectories of the first distance sensor 4 and the second distance sensor 5 respectively. It can be seen from FIG. The second distance sensor 5 is in contact with the pipe wall of the pipe material 1, which avoids the problem of inaccurate measurement results caused by friction between the first distance sensor 4 and the second distance sensor 5 and the pipe wall when the first distance sensor 4 and the second distance sensor 5 rotate and measure. In addition, the structure in this embodiment is simple and easy to operate, and the thickness value of the pipe wall of the pipe material 1 can be obtained simply and quickly. And there is no requirement to limit the thickness of the pipe material 1 .

Optionally, both the first distance sensor 4 and the second distance sensor 5 are laser sensors.

Specifically, distance sensors are mainly divided into optical sensors (mostly laser sensors), infrared sensors and ultrasonic sensors. In this embodiment, the measurement accuracy of the laser sensor is the highest.

However, for laser sensors, the wall of the pipe is required to reflect light, and the distance is measured based on this. Therefore, the measuring device in the present invention can measure any pipes with opaque materials, such as metal pipes, plastic pipes, ceramic pipes, etc., and has a wider application range compared with the measurement methods in the prior art.

It should be noted that, in FIG. 1 , the first distance sensor 4 and the second distance sensor 5 both measure a distance from the outside of the pipe 1 from the end of the pipe 1 . However, in actual operation, when the inner diameter of the pipe 1 is large enough, the first distance sensor 4 can also be located inside the pipe 1 for measurement, and the second distance sensor 5 can be rotated around the outer circumference of the pipe 1 for measurement.

In addition, the distances between the first distance sensor 4 and the second distance sensor 5 and the rotation center axis should be adjustable, and the measurement directions of the first distance sensor 4 and the second distance sensor 5 are also adjustable, so as to 1 measurement to accommodate pipes of different diameters.

Optionally, a distance measuring device may be further provided on the rotating support 3 .

Specifically, the distance measuring device may be a scale arranged on a rotating support and parallel to the movable direction of the first distance sensor and the second distance sensor, for measuring the first distance sensor 4 and the second distance sensor 5 respectively and The distance between the central axes of rotation.

However, in order to further facilitate the measurement and directly measure the data automatically by the device, a distance sensor can be set at the rotation point of the rotating bracket 3, and the distance sensor is connected to the processor. The distance sensor measures the first distance sensor 4 and the second distance sensor. After the distance data between the distance sensor 5 and the central axis of rotation, the distance data can be directly sent to the processor, and the processor can subsequently substitute it for direct calculation, without manual reading, simplifying the operation process and reducing the impact of manual reading. error.

Of course, other methods can also be used to measure the distance between the rotation center axis and the two distance sensors, which is not specifically limited in the present invention.

Optionally, in another specific embodiment of the present invention, the first distance sensor 4 and the second distance sensor 5 and the rotation center axis are located in the same plane, and the first distance sensor 4 and the second distance sensor 5 are respectively located in the rotation. both sides of the central axis.

Specifically, the first distance sensor 4 and the second distance sensor 5 and the rotation points on the rotating bracket 3 may be collinear with three points. When the rotating bracket drives the first distance sensor and the second distance sensor to rotate, the two can offset part of the torque with each other, thereby reducing the difficulty of rotation.

The present invention also provides a method for measuring the thickness of a pipe wall, using the device for measuring the thickness of a pipe wall provided by any of the above embodiments, as shown in FIG. 3 , which is a pipe wall provided by an embodiment of the present invention. A schematic flowchart of a thickness measurement method, which may include:

Step S11: Obtain the angle parameters and distance parameters of the first distance sensor and the second distance sensor in advance.

Specifically, the angle parameter includes the angle between the measurement directions of the first distance sensor and the second distance sensor and the rotation center axis, respectively.

The distance parameter is the distance between the first distance sensor and the second distance sensor and the rotation center axis, respectively.

Before measuring the thickness of the pipe wall, properly adjust the first distance sensor and the second distance sensor on the rotating bracket, so that the positions and measurement directions of the first distance sensor and the second distance sensor are roughly in an appropriate state, and then proceed to Measurement of angle parameters and distance parameters. After the angle parameter and the distance parameter are obtained by measurement, the distance between the first distance sensor and the second distance sensor relative to the rotation center axis and the measurement direction should not change.

Step S12: Fix the pipe to be tested on the fixing bracket.

Specifically, the pipe to be tested is fixed by a fixing bracket and the central axis of the pipe to be tested and the central axis of rotation are adjusted to be parallel to each other, and the distance between the central axis of rotation and the central axis of the pipe is smaller than the radius of the inner wall of the pipe.

Step S13: controlling the rotating bracket to drive the first distance sensor and the second distance sensor to rotate.

Specifically, both the first distance sensor and the second distance sensor rotate in a plane perpendicular to the pipe. In addition, the rotation surfaces of the first distance sensor and the second distance sensor may be on the same plane or on two surfaces parallel to each other, which is not limited in this embodiment.

Step S14: Obtain a plurality of first distances measured when the first distance sensor rotates and a plurality of second distances measured when the second distance sensor rotates.

The first distance sensor rotates once, and its measurement point pointing to the inner wall of the pipe also surrounds the inner wall of the pipe, so that a plurality of data of the first distance can be measured. Similarly, multiple second distances can also be measured.

Optionally, during actual measurement, the first distance sensor may measure the first distance between a group of first distance sensors and the inner wall of the pipe every time the rotating bracket drives the first distance sensor to rotate by a preset angle.

Similarly, every time the rotating bracket drives the second distance sensor to rotate by a preset angle, the second distance sensor measures the second distance between a group of second distance sensors and the inner wall of the pipe.

In the actual operation process, the rotating bracket can be rotated at a constant speed, and the first distance sensor and the second distance sensor can be measured at time intervals; it can also be directly measured according to the rotation angle of the rotating bracket at fixed angle intervals.

Step S15: Obtain the wall thickness of the pipe material according to the plurality of first distances, the plurality of second distances, the angle parameter and the distance parameter.

According to the spatial geometric relationship between the first distance sensor, the second distance sensor, the pipe material and the rotating support, and combining the data of the first distance and the second distance, the thickness of the pipe wall can be obtained.

The implementation method of obtaining the thickness of the pipe wall according to the first distance and the second distance in the above step S15 will be described below with specific examples.

Specifically, as shown in FIG. 4, FIG. 4 is a schematic flowchart of obtaining the thickness of the pipe wall provided by the embodiment of the present invention, and the specific steps include:

Step S21: Eliminate abnormal first distances and second distances according to preset conditions.

Specifically, for example, there are 5 sets of adjacent distance data l ₁ , l ₂ , l ₃ , l ₄ , l ₅ in the first distance, if l ₁ <l ₂ <l ₄ <l ₅ , l ₃ >l ₄ , and l ₃ >l ₂ , then l ₃ is the abnormal first distance. Similarly, anomalous second distances can be rejected in the same way.

Of course, the preset conditions for excluding the abnormal first distance and the second distance can be set according to the law that the distance data should follow in the actual measurement, which will not be described one by one.

Step S22: Select the largest first distance and the second distance and the smallest first distance and the second distance.

Step S23: Obtain the diameter of the inner wall of the pipe according to the largest first distance and the smallest first distance.

Step S24: Obtain the diameter of the outer wall of the pipe according to the largest second distance and the smallest second distance.

Specifically, reference can be made to FIG. 5, because during the measurement process of the first distance sensor, the position point where the maximum first distance is measured and the position point where the minimum first distance is measured should be exactly the end points of the same diameter of the inner wall of the pipe, according to formula D ₁ =(ρ _max +ρ _min )sinα ₁ +2d ₁ , that is, the diameter of the inner wall of the pipe is obtained; D ₁ is the diameter of the inner wall of the pipe, ρ _max and ρ _min are the maximum and minimum first distances, respectively, α ₁ is the angle parameter of the first distance sensor, and d ₁ is the distance parameter of the first distance sensor.

Similarly, according to the formula D ₂ =(r _max +r _min )sinα ₂ -2d ₂ , the diameter of the outer wall of the pipe is obtained; wherein, D ₂ is the diameter of the outer wall of the pipe, and r _max and r _min are the largest and smallest respectively Two distances, α ₂ is the angle parameter of the second distance sensor, and d ₂ is the distance parameter of the second distance sensor.

Of course, in actual measurement, it is also possible to directly measure only two sets of first distances and two sets of second distances, and the measurement points of the two sets of first distances are the two end points of the same diameter of the inner wall of the pipe, and the measurement points of the two sets of second distances are The point is the two end points of the same diameter of the outer wall of the pipe. Substitute the first distances of the two groups into the above formula instead of ρ _max and ρ _min in the above formula, and the diameter of the inner wall of the pipe can also be obtained. Similarly, the diameter of the outer wall of the pipe can be obtained in a similar way.

Step S25: Obtain the thickness of the pipe wall according to the diameter of the inner wall of the pipe and the diameter of the outer wall of the pipe.

The method in this embodiment is to measure and obtain the thickness value of the pipe wall under the premise that the thickness of the pipe is considered to be uniform. In actual measurement, only a few sets of distance data can be selected for calculation, which simplifies the calculation difficulty of pipe wall thickness.

In order to further improve the measurement accuracy of the pipe wall thickness, for the above step S13, another embodiment is also provided in the present invention, as shown in FIG. The schematic flow chart of the method, the method can specifically include:

Step S31: According to each group of the first distance and the corresponding rotation angle, the polar coordinates of the inner diameter circle of the pipe can be obtained.

Specifically, because the first distance sensor measures a set of first distances every time the first distance sensor rotates by a preset angle, multiple sets (ρ _n , θ _n ) can be obtained with the rotation of the first distance sensor, then, each measurement of the inner wall of the pipe The polar coordinates of the projection point of the point on the plane perpendicular to the pipe are (d ₁ +ρ _n sinα ₁ , θ _n ), where the origin of the polar coordinates is the projection point of the rotation center axis on the plane perpendicular to the pipe, and d ₁ is The distance parameter of the first distance sensor, ρ _n is the first distance of the nth group, α ₁ is the angle parameter of the first distance sensor, θ _n is the rotation angle corresponding to the first distance of the nth group, and n is a positive Integer.

According to the polar coordinates (d ₁ +ρ _n sinα ₁ , θ _n ), the inner diameter circle of the pipe can be obtained by fitting, thereby obtaining the inner diameter of the pipe.

Step S32: According to each group of the second distance and the corresponding rotation angle, the polar coordinates of the outer diameter circle of the pipe can be obtained.

Similarly, with the same principle as step S31, the projected point polar coordinates (d ₂ -rn sinα ₂ , θ _n ) of each measurement point on the outer wall of the pipe can be obtained, _where d ₂ is the distance parameter of the second distance sensor , rn is the second distance of the _nth group, α ₂ is the angle parameter of the second distance sensor, θ _n is the rotation angle corresponding to the second distance of the nth group; thus, the size of the outer diameter of the pipe can be obtained.

Step S33 : obtaining the inner diameter circle and the outer diameter circle of the pipe material by fitting according to the polar coordinates of the inner diameter circle and the polar coordinates of the outer diameter circle of the pipe material.

Specifically, as shown in FIG. 7 , FIG. 7 is a schematic diagram of an inner diameter circle and an outer diameter circle of a pipe material provided by an embodiment of the present invention. In Figure 7, each point is obtained according to the polar coordinates (d ₁ +ρ _n sinα ₁ , θ _n ) and (d ₂ -rn sinα ₂ , θ _n ), O _{1 is} the center of the inner diameter of the pipe, and O ₂ is the pole Coordinate origin.

Step S34: According to the inner diameter circle and the outer diameter circle of the pipe material, the thickness of the pipe wall of the pipe material is obtained.

In this embodiment, multiple sets of distance data measured by the first distance sensor and the second distance sensor are used to obtain the inner diameter circle and outer diameter circle of the pipe material, and the pipe wall thickness at each position around the pipe material can be accurately obtained, which makes the measurement of the pipe material thickness more accurate. Accurate and able to measure the problem of tube deformation.

Optionally, in another specific embodiment of the present invention, after obtaining the thickness of the pipe wall, it may further include:

Determine whether the difference between the thickness of the pipe wall and the standard thickness is within the preset range, if so, the pipe is qualified; if not, the pipe is unqualified; output the measurement result.

In most cases, the ultimate purpose of measuring the pipe diameter is to detect whether the thickness of the pipe wall meets the production requirements. Taking plastic pipes of PPR, PVC and other materials as an example, during the processing process, the extrusion manufacturing process of plastic pipes on the production line takes about seven seconds. Therefore, only when the time of the finished product quality inspection process is not more than this time can the efficiency of the processing production line be improved to the maximum efficiency. One of the most important quality inspection procedures in plastic pipe processing and manufacturing is wall thickness detection. Obviously, the current conventional plastic pipe wall thickness detection cannot achieve such a detection speed.

In the detection method provided by the present invention, the thickness of the pipe wall of the pipe can be detected within the required time, and the production efficiency of the pipe can be improved.

Based on any of the above embodiments, as mentioned above, there are various measurement methods for the angle parameters and distance parameters of the first distance sensor and the second distance sensor, but the parameters measured by means of sensors or other conventional measurement devices often fail to meet the accuracy requirements . Therefore, in another specific embodiment of the present invention, another method for measuring an angle parameter and a distance parameter based on a dual-sample calibration method is provided, and the method may include:

Step S41: Fix the first standard pipe on the fixing bracket.

It should be noted that the first standard pipe material refers to a pipe material whose inner wall diameter L ₁₁ and outer wall diameter L ₁₂ are known, and the thickness of the pipe wall is uniform.

Step S42: Control the rotation of the rotating support to obtain the maximum and minimum first distances of the inner wall of the first standard pipe measured by the first distance sensor; obtain the maximum and minimum second distances of the inner wall of the first standard pipe measured by the second distance sensor.

The specific measurement process is the same as the process in which the rotating bracket drives the first distance sensor and the second distance sensor in the above-mentioned embodiment, which will not be repeated here.

Through this step, the maximum first distance ρ ₁ and the minimum first distance ρ ₂ of the first distance sensor relative to the inner wall of the first standard pipe material can be obtained.

Through this step, the maximum second distance r ₁ and the minimum second distance r ₂ of the second distance sensor relative to the outer wall of the first standard pipe can also be obtained.

Step S43: Fix the second standard pipe on the fixing bracket.

The second standard pipe material is a pipe material whose inner wall diameter L ₂₁ and outer wall diameter L ₂₂ are known, and the thickness of the pipe wall is uniform.

Step S44: Control the rotation of the rotating support to obtain the maximum and minimum first distances of the inner wall of the second standard pipe measured by the first distance sensor; obtain the maximum and minimum second distances of the outer wall of the second standard pipe measured by the second distance sensor.

Referring to step S42, the maximum first distance ρ ₃ and the minimum first distance ρ ₄ of the first distance sensor relative to the inner wall of the second standard pipe material can be obtained; and the maximum second distance r of the second distance sensor relative to the outer wall of the first standard pipe material ₃ and the minimum second distance r ₄ .

Step S45: According to the largest and smallest first distances, the largest and smallest second distances relative to the inner wall of the first standard pipe, and the largest and smallest first distances, the largest and the smallest relative to the inner wall of the second standard pipe The second distance of , obtains the angle parameter and the distance parameter.

Referring to Figure 5, the same geometrical principle as the above-mentioned embodiment can be obtained according to the geometrical positional relationship:

L ₁₁ =(ρ ₁ +ρ ₂ )sinα ₁ +2d ₁ (1)

L ₁₂ =(r ₁ +r ₂ )sinα ₂ -2d ₂ (2)

L ₂₁ =(ρ ₃ +ρ ₄ ) sinα ₁ +2d ₁ (3)

L ₁₂ =(r ₃ +r ₄ )sinα ₂ -2d ₂ (4)

Wherein, α ₁ is the angle parameter of the first distance sensor, and d ₁ is the distance parameter of the first distance sensor;

α ₂ is the angle parameter of the second distance sensor, and d ₂ is the distance parameter of the second distance sensor;

ρ ₁ and ρ ₂ are respectively the maximum first distance and the minimum first distance of the first distance sensor relative to the inner wall of the first standard pipe;

r ₁ and r ₂ are respectively the maximum second distance and the minimum second distance of the second distance sensor relative to the outer wall of the first standard pipe;

L ₁₁ and L ₁₂ are respectively the first standard pipe material, which refers to the inner wall diameter and the outer wall diameter;

ρ ₃ and ρ ₄ are respectively the maximum first distance and the minimum first distance of the first distance sensor relative to the inner wall of the second standard pipe;

r ₃ and r ₄ are respectively the maximum second distance and the minimum second distance of the second distance sensor relative to the outer wall of the first standard pipe;

L ₂₁ and L ₂₂ are the inner wall diameter and the outer wall diameter of the second standard pipe material, respectively.

According to formula (1) and formula (3), it can be obtained:

再将获得的sinα₁代入公式(1)或公式(3)均可获得第一距离传感器的距离参数d₁。

Substitute the obtained sinα ₁ into formula (1) or formula (3) to obtain the distance parameter d ₁ of the first distance sensor.

However, it can be known from the above embodiment that the thickness of the pipe wall can be obtained only by obtaining the sine value of α ₁ . Therefore, in this embodiment, only sin α ₁ can be obtained, but the specific angle value can also be obtained by the sine value.

Similarly, sinα ₂ and d ₂ can be obtained according to formula (2) and formula (4).

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts of the various embodiments may be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

Claims (9)

1. The device for measuring the thickness of the pipe wall of the pipe is characterized by comprising a fixed support for fixing the pipe to be measured, a rotary support, a first distance sensor, a second distance sensor and a processor, wherein the first distance sensor and the second distance sensor are arranged on the rotary support;

the rotating bracket can drive the first distance sensor and the second distance sensor to rotate around a rotating central shaft, the rotating central shaft is parallel to the central shaft of the pipe, and the distance between the rotating central shaft and the central shaft of the pipe is smaller than the inner diameter of the pipe;

the first measuring direction of the first distance sensor points to the inner wall of the pipe and is not parallel to the rotating central shaft, and the first measuring direction can be changed along with the rotation of the first distance sensor, so that the first distance sensor can measure first distances between a plurality of position points of the inner wall of the pipe;

a second measuring direction of the second distance sensor is directed toward the outer wall of the pipe and is not parallel to the central axis of rotation, the second measuring direction being changeable with rotation of the second distance sensor so as to provide a second distance between the second distance sensor and a plurality of points on the outer wall of the pipe;

the processor is connected with the first distance sensor and the second distance sensor, and the thickness of the pipe wall of the pipe is obtained according to the first distance and the second distance;

the first distance sensor and the second distance sensor are respectively used for measuring the first distance and the second distance from the outer part of the pipe to the end part of the pipe at preset distance positions;

the first distance sensor and the second distance sensor are both laser sensors;

the distance between the first distance sensor and the second distance sensor on the rotating support relative to the rotating central shaft is adjustable, and the measuring directions of the first distance sensor and the second distance sensor are both adjustable.

2. The apparatus of claim 1, wherein the first and second distance sensors and the central axis of rotation are in the same plane, and the first and second distance sensors are located on either side of the central axis of rotation.

3. The apparatus according to any one of claims 1 to 2, wherein the rotating bracket is further provided with a distance measuring device for measuring the distance between the first distance sensor and the second distance sensor and the rotating central shaft.

4. A pipe wall thickness measuring method using the pipe wall thickness measuring apparatus according to any one of claims 1 to 3, comprising:

obtaining angle parameters and distance parameters of a first distance sensor and a second distance sensor in advance, and fixing the pipe to be measured on a fixed support; the angle parameter comprises an included angle between the measuring directions of the first distance sensor and the second distance sensor and a rotating central shaft respectively, and the distance parameter is a distance between the measuring directions of the first distance sensor and the second distance sensor and the rotating central shaft respectively;

controlling a rotating bracket to drive a first distance sensor and a second distance sensor to rotate around the rotating central shaft;

obtaining a plurality of first distances measured when the first distance sensor rotates and a plurality of second distances measured when the second distance sensor rotates;

and obtaining the pipe wall thickness of the pipe according to the plurality of first distances, the plurality of second distances, the angle parameter and the distance parameter.

5. The measuring method according to claim 4, wherein the step of the first distance sensor measuring the first distance comprises:

the rotating bracket drives the first distance sensor to rotate by a preset angle every time, and the first distance sensor measures a group of first distance between the first distance sensor and the inner wall of the pipe;

the rotating support drives the second distance sensor to rotate by a preset angle every time, and the first distance sensor measures a group of second distances between the second distance sensor and the inner wall of the pipe.

6. The measurement method of claim 5, wherein the obtaining a wall thickness of the tubing from the first and second distances comprises:

according to each group of the first distance and the corresponding rotation angle, the polar coordinate (d) of the inner diameter circle of the pipe can be obtained₁+ρ_nsinα₁,θ_n) Wherein d is₁Is a distance parameter, p, of the first distance sensor_nIs the nth set of first distances, α₁Is an angular parameter of the first distance sensor, theta_nThe rotation angle corresponding to the nth group of first distances;

according to each group of the second distance and the corresponding rotation angle, the polar coordinate (d) of the outer diameter circle of the pipe can be obtained₂-r_nsinα₂,θ_n) Wherein d is₂For the second distance transmissionDistance parameter of sensor, r_nIs the nth set of second distances, α₂Is an angular parameter of the second distance sensor, θ_nThe rotation angle corresponding to the nth group of second distances is shown, and n is a positive integer;

according to the polar coordinates (d) of the inner diameter circle₁+ρ_nsinα₁,θ_n) And the polar coordinates (d) of the outer diameter circle₂-r_nsinα₂,θ_n) Fitting to obtain an inner diameter circle and an outer diameter circle of the pipe;

and obtaining the pipe wall thickness of the pipe according to the radii of the inner diameter circle and the outer diameter circle.

7. The measurement method of claim 5, wherein the obtaining a wall thickness of the tubing from the first and second distances comprises:

rejecting abnormal first distance and second distance according to a preset condition;

selecting the largest first distance and the second distance and the smallest first distance and the smallest second distance;

according to formula D₁＝(ρ_max+ρ_min)sinα₁+2d₁Obtaining the diameter of the inner wall of the pipe; wherein D is₁Is the diameter of the inner wall of the pipe, rho_max、ρ_minA first distance, a, of maximum and minimum respectively₁As an angular parameter of the first distance sensor, d₁Is a distance parameter of the first distance sensor;

according to formula D₂＝(r_max+r_min)sinα₂-2d₂Obtaining the diameter of the outer wall of the pipe; wherein D is₂Is the diameter of the outer wall of the pipe, r_max、r_minMaximum and minimum second distances, alpha, respectively₂For said second distance sensor angle parameter, d₂Is a distance parameter of the second distance sensor;

and obtaining the pipe wall thickness of the pipe according to the pipe inner wall diameter and the pipe outer wall diameter.

8. The measurement method according to any one of claims 4 to 7, wherein the obtaining in advance the angle parameter and the distance parameter of the first and second distance sensors includes:

fixing the first standard pipe on a fixed bracket;

controlling a rotating bracket to rotate around the rotating central shaft, and measuring by the first distance sensor to obtain a first distance which is maximum and minimum relative to the inner wall of the first standard pipe, and measuring by the second distance sensor to obtain a second distance which is maximum and minimum relative to the outer wall of the first standard pipe;

fixing the second standard pipe on a fixed bracket;

controlling a rotating bracket to rotate around the rotating central shaft, and measuring by the first distance sensor to obtain a first distance which is maximum and minimum relative to the inner wall of the second standard pipe, and measuring by the second distance sensor to obtain a second distance which is maximum and minimum relative to the outer wall of the second standard pipe;

obtaining the angle parameter and the distance parameter according to the maximum and minimum first distances, the maximum and minimum second distances relative to the inner wall of the first standard pipe, and the maximum and minimum first distances, the maximum and minimum second distances relative to the inner wall of the second standard pipe.

9. The measurement method according to claim 8, further comprising, after obtaining a wall thickness of the tubing:

and judging whether the difference value between the pipe wall thickness and the standard thickness is within a preset range, if so, determining that the pipe is qualified, and outputting a measurement result.

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