RU2111452C1 - Method for measuring channel pipe geometry and device for its embodiment - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: when measuring the channel pipe geometry, simultaneously with measuring the pipe warping pipe diameter and shift of angle meter case axis relative to pipe walls are measured. Measurement data are used for calculation of fluctuations of angle between angle meter axis and channel pipe axis. Device has two diameter meters, two centering mechanisms, angle meter and measuring unit. EFFECT: higher measurement results. 3 cl, 2 dwg

Description

 The specified invention relates to the field of measuring technology and is used to determine the geometry of channel pipes, boreholes, technological channels of nuclear reactors, product pipelines.

 Known methods for measuring geometry, consisting in the separate transportation through the pipe of the tilt and diameter meters or the simultaneous transportation of functionally unrelated tilt and diameter meters [1].

 The disadvantage of these methods is the low accuracy of the measurement due to uncontrolled distortions of the casing of the tilt and diameter meters in the pipe caused by the action of the drive, as well as inaccuracies in the alignment of the body due to fluctuations in the diameter of the pipe.

 The aim of the invention is to improve the accuracy of measurements.

 This goal is achieved due to the fact that when measuring the geometry of channel pipes simultaneously with measuring pipe curvature, the pipe diameter and the displacement of the axis axis of the angle meter with respect to the pipe walls are measured, the angle fluctuations between the body axis and the pipe axis are calculated from the measurements, the angle fluctuation value is subtracted from the readings of the angle meter and use this difference to calculate the value of the diameter of the channel pipes.

This goal is also achieved due to the fact that the device for measuring the geometry of the channel pipes, comprising a housing, two centering mechanisms located along the axis of the housing, an angle meter and a diameter meter, a drive and a measuring unit, is equipped with a second diameter meter mounted relative to the first at an angle of 45 ^o, the diameter of each of the gauges situated in the plane corresponding centering mechanism, each of which is designed as a bellows chamber cruciform shape with flat screens are arranged GOVERNMENTAL with the inner side of the chamber and mounted respectively on the outer side rollers and the drive is electrically connected with the measuring unit. The diameter meters are identical in the form of a square rod located in the center of the cross, on the sides of which there are 4 piezo-emitters, respectively facing the ends of the bellows chambers.

 In FIG. 1 shows a graphical interpretation of the proposed method for measuring the geometry of channel pipes. In FIG. 2 shows a device that implements the method.

Methods for measuring the geometry of channel pipes are carried out by measuring the angle of inclination of the axis of the pipe with an angle meter with respect to a fixed direction, for example, a vertical, in a series of reference points along the pipe spaced apart by the length of the base H of the housing 1 of the angle meter. Because in the planes X - X and Y - Y of the body of the angle meter, centering mechanisms 2, 3 are usually placed, the assumption is made that the points A _x and A _y on the axis of the body of the angle meter lie also on the axis 4 of the channel pipe 5 (Fig. 1). During the course of measuring the angle from the bottom up, the displacement δy _{i of the} point A _yi is determined relative to the displacement δx _{i of the} point A _xi according to the formula
δy _i = δx _i + H sin φ _i , (1),
Where
φ _i - readings of the angle meter 6 (Fig. 1).

 The diameter is measured in the plane of the cross section of the pipe, on the line of maximum diameter, for which it is also necessary that the axis of the meter diameter housing coincide with the axis of the channel pipe.

The measurement experience shows that when the device’s body moves along the pipe under the action of the actuator 7, the axis 8 of the housing of the angle meter (diameter meter) uncontrollably leaves the axis 4 of the channel pipe 5 even in the XX, YY planes, the placement of centering mechanisms for the following main reasons:
- the transverse component of the action of the drive on the upper end of the housing 1 of the meter of angles (diameter) inside the pipe 5, leads to distortions of the housing inside the pipe 5;
- fluctuations in the diameter of the pipe lead to a shift of the equilibrium point between two opposite supports 9, 10, each of the centering mechanisms 2, 3, which also leads to a mismatch of the axes 4 and 8;
- unequal coefficient of friction against the pipe wall of the contact supports 9, 10 of the centering mechanisms, which may be due to the presence of inhomogeneous deposits on the pipe walls in the case of a sliding support, or the probable jamming of the roller bearings, leads to distortions of the housing;
- accidental distortions, for example, from obstacles during movement;
- distortions caused by the hit of supports on caverns, inclusions, other local defects.

 All of the above factors lead to the fact that the angular readings of the angle meter 6 correspond to the inclination of the housing 1 of the angle meter 6, and not to the tilt of the axis 4 of the channel pipe, and the readings of the diameter meter do not correspond to the diameter in the cross section plane X'-X 'of the pipe 5 (Fig. 1, position 2), and some in the distance between the pipe walls in the section X - X. Another consequence of the distortions of the housing 1 is the departure of the contact supports of the diameter meter from the line of maximum diameter A - A to the line A '- A', which corresponds to one of the chords cross section pipes (see Fig. 2, section Y - Y).

 A method and apparatus for its implementation is proposed, by means of which an accurate measurement of the departure of the axis axis of the angle meter (diameter meter) from the axis of the channel pipe in the planes of the centering mechanisms, which allows you to calculate the angle fluctuations between the axis 8 of the housing 1 of the angle meter (diameter) and axis 4 channel pipe and then subtract them from the readings of the angle meter 6. In addition, the method allows to bring the plane of diameter measurement to the plane of the cross section of the pipe.

 The method is carried out due to the following methods and devices that implement it.

In the planes X - X, Y - Y of the housing 1 of the angle meter, distance meters are located from the conditional axis of the body 1 (rod of square section 11) of the angle meter to the opposite walls of the pipe. These meters are located in two orthogonal planes A - A, B-B and are made in the form of ultrasonic piezoelectric range finders containing piezoelectric elements 12, 13, 14, 15, which are connected to the measuring unit 16 (Fig. 2). The range finder with the piezoelectric element 12 measures the displacement Y ₁ , the range finder with the piezoelectric element 13 measures the displacement Y ₂ . The sum of the displacements Y ₁ and Y ₂ , adjusted for the thickness of the rod 11, gives the diameter of the channel pipe in the plane AA (Fig. 2) and in the cross section of the pipe Y - Y (Fig. 2).

In the same way, displacements and diameter are measured by means of range finders with piezoelectric elements 14, 15 in the plane B - B (Fig. 2) in the same section (Fig. 1). The meters 17 of distances X ₁ and X ₂ (Fig. 1) in cross section X - X and the plane C - C (Fig. 2) and the meter orthogonal to it in the plane D - D (Fig. 2) have a similar design. The planes for measuring the distances and diameters CC, DD in the X - X section are set relative to the planes for measuring the displacements and the diameters A - A, B - B, in the Y - Y section at 45 ^o in order to identify the pipe ellipsoidality and one-sided non-circularity of its section. These distance and diameter meters are located in the center of the crosspiece of the bellows 17, 18 having external contact rollers 19 and a reflective screen 20 at the ends of the bellows. For better ultrasound conductivity, the crosses can be filled with liquid 21 and communicate with the compensating chamber 22 (Fig. 2). The bellows allow you to hold the point M on the reflective screen 20 on the line of maximum diameter A - A even when the axis axis of the angle meter is shifted, for example, to the plane A '- A', due to its flexibility in all directions. The use of ultrasonic rangefinders as distance meters allows non-contact measurement of distances in two orthogonal planes, for example AA and BB in the same section (Y - Y), as well as fixing the distance from piezoelectric element 12 to point M in case the axis of the piezoelectric element is shifted from line A - A to the line A '- A' (Fig. 2) due to the spatial nature of the propagation of the ultrasonic wave, which in other types of displacement meters (inductive, capacitive) in case of violation of the relative position of the sensitive elements is not plane ti measurements difficult. The contact rollers 19 are used to fix the points k ₁ - k ₂ between which the diameter is measured, including due to friction of the support against the pipe wall in cases of sharp distortions of the housing. In addition, the point of contact with the pipe wall M of the rollers 19, provided that they are mounted on a flexible bellows, when the diameter meter is shifted to the plane A '- A', "rolls" to the line of maximum diameter AA, which leads to the effect of "auto-correction" supports 19 during the movement of the diameter meter.

 A method for measuring the geometry of pipes is to perform the following procedures.

1. In the initial state (position 1), the housing 1 of the device is stationary, the axes 4 and 8 of the pipe 5 and the housing of the angle meter 1 are offset relative to each other by an angle α _o .

In this position, the distances X ₁ , X ₂ in the section X - X, the distances Y ₁ , Y ₂ in the section Y - Y, the angle φ _{o of the} angle meter are measured 6. When using the multi-coordinate angle meter (gyroscopic or accelerometer), all angular coordinates are measured . For simplicity, we consider the implementation of the method in one plane of the drawing (Fig. 1).

здесь
(x1o+x2o)/2 - радиус трубы 5 в сечении X - X, (y1o+y2o)/2 - то же в сечении Y - Y.According to the measurements, the initial settings Δx _o , Δy _{o are found} between the axes 8 and 4 of the angle meter and the pipe in the lower X - X and upper Y - Y sections according to the formula

here
(x1o + x2o) / 2 - the radius of the pipe 5 in the section X - X, (y1o + y2o) / 2 - the same in the section Y - Y.

The initial angle α _o between the axes 8 and 4 is determined by the formula
α _o = arctan [(Δx _o -Δy _o ) / H] (4),
Where
H is the distance between the centering mechanisms of the device.

Таким образом, диаметр из плоскости фактического измерения xi - xi, yi - yi, приводится к плоскости поперечного сечения трубы xi' - xi', yi' - yi'.2. Having calculated the mismatch angle of the axes α _o , the diameter is corrected in sections X - X and Y - Y, according to the formula

Thus, the diameter from the plane of actual measurement xi - xi, yi - yi, is reduced to the plane of the cross section of the pipe xi '- xi', yi '- yi'.

3. Find the angle of inclination of the axis 4 of the channel pipe by the formula
φ $\genfrac{}{}{0ex}{}{\text{ist}}{\text{about}}$ = φ _o ± α _o . (7)
Determine the offset δy _{o of the} reference point Ay ₀ relative to the offset δx _{o of the} reference point Ax by the formula
δy _o = δx _o + H sin φ $\genfrac{}{}{0ex}{}{\text{ist}}{\text{about}}$ . (eight)
If we take δx _o = 0 for the initial point, then we obtain
δy _o = H sinφ $\genfrac{}{}{0ex}{}{\text{ist}}{\text{about}}$ . (nine)
When moving the device case to the i-th number of reference points (position 2), current measurements are taken of the distances X ₁ , X ₂ , Y ₁ , Y ₂ from the axis of the body to the walls of the channel pipe.

According to measurements, using the formulas (2 - 8), find the current angle α _i , the true diameter in the planes xi '- xi', yi '- yi', the true angle φ $\genfrac{}{}{0ex}{}{\text{ist}}{\text{i}}$ the slope of the axis of the channel pipe at the reference points, and according to formula 1, the coordinates of the i-th point are found.

For more accurate calculations, after calculating the true diameter (paragraph 2, formulas 5, 6), recalculate Δx _o , Δy _o , α _i taking into account the new value of the diameter (radius) by the method of successive approximations to the required convergence of the results.

 With significant distortions of the device case, even despite the effect of "auto-correction" of the supports described above, the supports 9, 10 can go away from the line of maximum diameter A - A to the circle line A '- A' (Fig. 2).

 This effect occurs if the meters do not have distances from the axis of the device body to the pipe walls, or devices of point contact with the pipe wall.

В действительности, сечение труб не всегда является круглым. А для строгой идентификации эллипсоидного сечения необходимо проводить измерения диаметра как минимум в четырех плоскостях. Для этого нижняя крестовина сильфонов развернута относительно верхней на 45^o.In this case, the following method of processing the results is proposed. Since the amount of displacement from the plane A - A to the plane A '- A' of the diameter meter on line A - A is a value equal to Δy _i , determined in plane B - B from expression 3, and the diameter DAi 'in plane A' - A 'is known from the testimony of the diameter working in the plane A' - A ', the true diameter in the plane A - A is determined from the expression

In fact, the cross section of pipes is not always round. And for strict identification of the ellipsoidal cross-section, it is necessary to measure the diameter in at least four planes. For this, the lower crosspiece of the bellows is deployed relative to the upper one by 45 ^o .

 After both diameter meters (upper 18 and lower 17) have passed through one section, the ellipsoidality is identified, and the true diameter in expression (10) is already calculated from the ellipse equation.

Since the lower crosspiece of the bellows 17 is deployed relative to the upper 18 by 45 ^° in the measurement plane, it is necessary to provide the measurement data of the distances x1i, x2i, y3i, y4i from the axis of the device body from the planes C - C and D - D to the planes A - A and B - B. The specified reduction is carried out by bringing one coordinate system to another.

The proposed method and device allows you to measure the angle fluctuations between the axes 4 and 8 with an accuracy quite comparable with the accuracy of the angle meter 6. So, for example, if the sensitivity of the ultrasonic range finder in sections X - X, Y - Y is 0.01 mm, then the accuracy measuring the angle α _i is
Δα _i = arctan (0.01 / H),
which, when the distance between the centering mechanisms H, for example 400 mm, is 5 ''. About the same sensitivity have the best of the known angle meters.

 The device allows you to measure the curvature and diameter in one pass through the pipe, which significantly increases the efficiency of measurements.

 The method can be implemented on goniometers that do not have special centralizers.

In places of abnormal diameter jumps (caverns, inclusions), the angular measurement data are approximated by previous values or are canceled, because in this case, it is impossible to determine the true radius of the channel pipe and to make an accurate correction of the angle φ _i .

 The design of the device has a sign of "unity", because the readings of angle and diameter meters in the above-described design are inter-correlated. The readings of distance meters from the device body to the pipe walls in two orthogonal planes are also mutually correlated. Therefore, it is the cross-shaped supports and the corresponding displacement meters in the planes of the centering mechanisms that allow for accurate correction of the diameters and values of the angle of inclination of the channel pipes when the body of the device is skewed.

 Ultrasonic range finders with piezoelectric elements allow the device to be operated in harsh temperature and radiation conditions, which is predetermined by the high resistance of piezoceramics.

 Bellows centralizers in addition to the effect of "auto-correction" of the maximum diameter line are a reliable pressure-resistant assembly, especially in combination with a compensating bellows and liquid inside the body cavity.

The displacement meter in each of the planes can be made in the form of one piezoelectric element located at the end of one of the bellows, measuring two distances:
1 - from the end of one bellows to the end of the opposite bellows (pipe diameter);
2 - from the end of the bellows to the Central rod (the distance between the axis of the housing of the device and the pipe wall).

 To ensure the passage of the same ultrasonic wave through the rod to the screen of the opposite bellows, the rod can be made, for example, in the form of a washer with a central hole equal to the diameter of the piezoelectric element. In this case, the first reflected pulse will correspond to the distance from the piezoelectric element to the washer, the second to the distance to the end of the opposite bellows, see FIG. 2 sections X - X.

 In addition to simplifying the measuring circuit, this design allows you to filter out noise and noise reflected from the opposite screen, as well as to localize the ultrasonic location zone around point M lying on the line of maximum diameter. These washers are located within the bellows chambers so as not to block the ultrasonic path orthogonal to the diameter meter with their body.

 The proposed method and device for its implementation allows an accurate assessment of the position of the housing of the control device of the geometry of the channel pipes relative to these pipes, which makes reliable the readings of the angle meter, which are used to count the profile of pipes, horizontal and vertical laying of pipelines, product pipelines, drilling, wells, etc. d. This task is especially urgent in nuclear energy when controlling the curvature and diameter of the technological channels of nuclear reactors, on which the trouble-free operation of the reactor depends. In this case, the requirements for measurement accuracy are an order of magnitude higher than in geology, drilling, and other industries. The experience of controlled procedures on technological channels shows that even the smallest disturbing factors affecting the distortions of the body of the angle and diameter meter lead to unacceptable measurement errors.

 The above method with a device is the only possible option to obtain reliable results with respect to the geometry of the channel pipes in the presence of the above destabilizing factors.

Claims (3)

 1. A method of measuring the geometry of channel pipes, which consists in measuring pipe curvature by measuring the angle of inclination of the pipe axis and its diameter in different sections, characterized in that simultaneously with measuring pipe curvature, the pipe diameter and the displacement of the axis of the housing of the angle meter relative to the pipe walls are measured, according to the measurement results, the angle fluctuation between the body axis and the pipe axis is calculated, the angle fluctuation values are subtracted from the readings of the angle meter, and this difference is used to calculate the diameter value channel pipes. 2. A device for measuring the geometry of channel pipes, comprising a housing, two centering mechanisms located along the axis of the housing, an angle meter and a diameter meter, a drive and a measuring unit, characterized in that it is equipped with a second diameter meter installed relative to the first at an angle of 45 ^o , each of the diameter meters is located in the plane of the corresponding centering mechanism, each of which is made in the form of a cross-shaped bellows chamber with flat screens located on the inside us chamber and mounted respectively on the outer side frames and the actuator is electrically connected with the measuring unit.  3. The device according to claim 2, characterized in that the diameter gauges are identical in the form of a square rod placed in the center of the cross, on the sides of which there are four piezo-emitters, respectively facing the ends of the bellows chambers.

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