Method for measuring at least one cross-sectional dimension of a cylindrical hollow body

Abstract

This disclosure relates to a method for measuring at least one cross-sectional dimension of a cylindrical hollow body, an apparatus for measuring at least one cross-sectional dimension of a cylindrical hollow body, and a cylindrical hollow body. The method and apparatus provide a more efficient measurement of the geometric properties of a cylindrical hollow body. [Solution] The method includes the steps of: providing a cylindrical hollow body; guiding a light beam from an interferometer device along a travel path toward the outer surface of the hollow body such that at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently; in the interferometer device, receiving a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the travel path; and obtaining at least one cross-sectional dimension of the hollow body based on interferometry of the portion of the light reflected from the outer surface and / or the portion of the light reflected from the inner surface, wherein the method includes the step of changing the orientation of the travel path of the light beam toward the hollow body.

Description

[Technical Field]

[0001] This disclosure relates to a method for measuring at least one cross-sectional dimension of a cylindrical hollow body, an apparatus for measuring at least one cross-sectional dimension of a cylindrical hollow body, and a cylindrical hollow body. The method and apparatus provide a more efficient measurement of the geometric properties of a cylindrical hollow body. [Background technology]

[0002] Tubular, hollow cylindrical bodies are useful for storing pharmaceuticals when manufactured as pharmaceutical containers. The demand for and standards for pharmaceutical containers are constantly increasing, aiming to provide and guarantee the quality of transported pharmaceuticals and to allow stored pharmaceuticals to be inspected unobstructed, preferably with the naked eye.

[0003] Regarding the geometric properties of glass tubes and polymer tubes, methods for measuring them are known in the art. Different methods are used to determine the outer diameter, inner diameter, and wall thickness. For measuring the outer diameter, the transmitted light method is used, in which the projected shadow is recorded with a camera and the obtained image is analyzed to derive the outer diameter. The wall thickness is typically measured by the chromatic confocal method and the interferometry method. Both methods are suitable for measuring wall thickness if, as a condition, the measurement axis of each measurement head is oriented perpendicular to the tube surface and passes through the center of the tube cross-section. If this requirement is not met, the chromatic-confocal measurement method will produce measurement errors, and the interferometry method will suffer signal interruptions. Deviations from orthogonal alignment in the two methods can arise from the movement of the tube and / or vibration of the tube. The aforementioned problem is most pronounced in the case of glass tubes where the curvature of the surface gradually increases, i.e., glass tubes with small outer diameters, and thus it is particularly difficult, and in some cases substantially impossible, to establish orthogonal alignment of the measurement axis with respect to the tube surface. There is no direct method for measuring the inner diameter, but it is typically calculated from the outer diameter and wall thickness.

[0004] International Publication No. 2012 / 117353 discloses an apparatus and method for measuring the thickness of a wall of a transparent object. The wall includes a transparent material positioned between a proximal interface set between the environment and the transparent material and a distal interface set between the transparent material and the environment. The apparatus comprises a source of initiation light emission and means for focusing it, obtaining incident light emission toward the wall that strikes the proximal interface of the object's wall and is partially reflected, thereby generating a first reflected emission. A portion of the incident light emission that has passed through the transparent material strikes the distal interface, is then reflected, and travels through the proximal interface in the opposite direction from the transparent material, thereby generating a second reflected emission. The collected emission, obtained by superimposing the first and second reflected emissions, has an intensity difference configured to obtain interference, thereby making it possible to determine the thickness of the wall. The focusing means comprises a lens means having two principal meridians orthogonal to each other, thereby focusing the incident light emission to a first virtual focus in the first meridian plane and a second virtual focus in the second meridian plane. In this way, the collected radiation is substantially independent of the potential movement of the transparent object, enabling reliable and robust measurements with respect to object fluctuations and vibrations.

[0005] International Publication No. 2021 / 024127 discloses an apparatus and optical detection method for non-contact dimensional measurement of the inner diameter of a tube along a manufacturing line, the apparatus comprising at least one optical thickness measuring sensor and at least one diameter measuring sensor for measuring the outer diameter of the tube. Each diameter measuring sensor and at least one thickness measuring sensor are constrained to a support so as to be radially oriented with respect to the geometric axis of the tube. The thickness measuring sensor measures the thickness of the portion of the tube belonging to the outer diameter of the tube detected by the diameter measuring sensor. The thickness measuring sensor and the diameter measuring sensor are synchronized to measure simultaneously. The inner diameter of the tube is calculated as the difference between the detected outer diameter and thickness of the tube. Supports fixed above or inside the thickness measuring sensor and the diameter measuring sensor ensure that the measurements lie on the same axis perpendicular to the geometric axis of the tube.

[0006] There is still a need to provide more efficient devices and detection methods than those described in this art. [Overview of the project] [Means for solving the problem]

[0007] In one embodiment, the present disclosure provides a method for measuring at least one cross-sectional dimension of a cylindrical hollow body, the hollow body having a wall surrounding the lumen, a longitudinal axis, an inner surface and an outer surface, and the method is -The step of providing a cylindrical hollow body, - The steps of guiding a light beam along a travel path from an interferometer device toward the outer surface of a hollow body such that at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently, - In an interferometer device, the steps include receiving a portion of the light reflected from the outer surface and receiving a portion of the light reflected from the inner surface along the travel path, - The step of obtaining at least one cross-sectional dimension of a hollow body based on interferometry of a portion of the light reflected from the outer surface and / or a portion of the light reflected from the inner surface, This method, - This method is characterized by including the step of changing the direction of the light beam's path toward the hollow body.

[0008] Interferometric measurements rely on receiving at least two separate light beams with different optical paths. The two light beams may interfere constructively or destructively. Measuring the dimensions of at least one cross-sectional area of ​​a cylindrical hollow body can be inaccurate if the initial light beam does not reach the outer surface of the hollow body at the correct angle, as it is necessary to receive a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the moving path in the interferometer device. In other words, if the initial light beam reaches the outer surface of the hollow body at an angle too far from the orthogonal angle, the portions of light reflected from the outer and inner surfaces may not be detected. The problems described may be particularly noticeable on hollow bodies with small outer diameters that need to be perfectly mounted for the required measurement. The problems described are also more noticeable when measuring hollow bodies in or along a production line, as mechanical vibrations can lead to signal fluctuations or loss of signal in the detector. In view of this, the inventors have developed a method for receiving a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the travel path in an interferometer device, even when mechanical vibrations of the hollow body are present. The developed method does not require any specific mounting of the hollow body, as long as at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently. Accordingly, the method is characterized by including a step of changing the orientation of the travel path of the light beam toward the hollow body. This feature provides that at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently at an angle sufficient to receive a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the travel path in the interferometer device. This feature increases the number of (successful) detections by chance in the interferometer device. Accordingly, the method of the present disclosure is more reliable and more robust. The method of the present disclosure also provides more data points for measuring at least one cross-sectional dimension of a cylindrical hollow body, even when mechanical vibrations are present on the cylindrical hollow body, for example, when it is on a manufacturing line and / or improperly mounted. When a specific data throughput is desired, the method disclosed herein is also faster because it provides more successful detection events.

[0009] In a second aspect, the present disclosure provides an apparatus for measuring at least one cross-sectional dimension of a cylindrical hollow body, The apparatus comprises at least one interferometer device and a scanner, The scanner can be positioned to guide the synchrotron radiation beam from at least one interferometer device along a trajectory toward the outer surface of the hollow body. The device is characterized by its ability to change the direction of the synchrotron radiation beam's movement path using a scanner.

[0010] The disclosed apparatus solves the problems of the prior art and provides more reliable and robust measurements of cylindrical hollow bodies.

[0011] For interferometry, an alignment in which the measurement axis and the tube surface are essentially orthogonal is crucial for obtaining measurements from reflected light at each of the interfaces encountered, i.e., in the case of a glass tube, at the first outer interface air / glass, the first inner interface glass / air, the second inner interface air / glass, and the second outer interface glass / air. Each interferometry method specifies a relatively small acquisition angle. For example, the acquisition angle for the Precitec CHRocodile sensor is 2°. If the measurement axis deviates from mathematically perfect orthogonal alignment with respect to the tube surface by more than about half the acquisition angle, no measurements will be obtained.

[0012] A scanner that can change the orientation of the synchrotron radiation beam's path allows for the detection of more data points to measure at least one cross-sectional dimension of a cylindrical hollow body, even when mechanical vibrations are present and / or the hollow body is improperly mounted. The scanner changes the orientation of the synchrotron radiation beam's path so that nearly orthogonal alignment of the measurement axis with respect to the hollow body surface is achieved more frequently than when the synchrotron radiation beam's path is static.

[0013] Both the method and apparatus according to the present disclosure enable interferometric measurement of a cylindrical hollow body that is in an imperfect orientation with respect to an optical beam, for example, due to mechanical vibrations resulting from conveyance along a production line. The method and apparatus can also provide direct measurement of a first wall thickness, inner diameter, second wall thickness, and / or outer diameter along a single measurement axis. The method and apparatus are particularly suitable for measuring glass and polymer tubes with relatively small outer diameters.

[0014] In a third aspect, the present disclosure provides a cylindrical hollow body having a longitudinal axis, an outer surface, and an inner surface, the hollow body having a first wall thickness (WT1), an inner diameter (ID), and a second wall thickness (WT2), The first wall thickness (WT1), inner diameter (ID), and second wall thickness (WT2) are measurable along any straight line perpendicular to the longitudinal axis, the straight line being one that virtually cuts through the hollow body, The outer diameter (OD) of the hollow body is 6 mm or less, The inner diameter (ID) of the hollow body is 5 mm or less, The absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) is less than 0.01 mm, or less than 0.001 mm, and / or The inner diameter has a tolerance of less than 0.01 mm, or less than 0.001 mm.

[0015] The method and apparatus of the present disclosure serve to provide cylindrical hollow bodies with excellent dimensional accuracy by enabling in-process control of the relevant manufacturing parameters.

Brief Description of the Drawings

[0016] [Figure 1A] Shows a cross-section of a hollow body according to the present disclosure. [Figure 1B] Shows a cross-sectional view of a further hollow body according to the present disclosure. [Figure 2A] Shows a measurement setup according to the prior art. [Figure 2B] Shows a measurement setup according to the prior art as shown in FIG. 2A. [Figure 3A] Shows a measurement setup according to the present disclosure. [Figure 3B] Further measurement setups are shown in this disclosure. [Modes for carrying out the invention]

[0017] Figure 1A shows a cross-section of the hollow body (4) according to this disclosure, displaying the first wall thickness (WT1), the second wall thickness (WT2), the inner diameter (ID), and the outer diameter (OD) along a straight line (L) passing through the diameter of the cross-section. The hypothetical intersections are labeled "10," "20," "30," and "40" along the path of the optical beam.

[0018] Figure 1B shows a cross-section of a hollow body according to the present disclosure, having an inner cross-section and an outer cross-section, where the inner cross-section may be approximated as an inner ellipse and the outer cross-section may be approximated as an outer ellipse.

[0019] Figure 2A shows a conventional measurement setup, where an interferometer device (1) radiates a light beam (3) toward the outer surface of a hollow body (4). A portion of the light beam (3) strikes the outer surface of the hollow body (4). However, as shown in the figure, if the axis of the light beam (3) is substantially off from the corresponding diameter of the cross-section of the hollow body (4), the reflected light (3) R ) does not reach the interferometer device (1).

[0020] Figure 2B shows a conventional measurement setup as shown in Figure 2A. The reflected light (3) is only available when the axis of the light beam (3) is substantially parallel to the corresponding diameter of the cross-section of the hollow body (4). R ) reaches the interferometer device (1).

[0021] Figure 3A shows the measurement setup according to this disclosure, displaying an interferometer device (1) and a scanner (2), where the interferometer device (1) emits a light beam (3) toward the outer surface of the hollow body (4). A portion of the light beam (3) strikes the outer surface of the hollow body. The scanner can change the axis of the light beam (3), thereby making the light beam (3) substantially parallel to the corresponding diameter of the cross-section of the hollow body (4). Thus, the reflected light (3 R ) reaches the interferometer device (1).

[0022] Figure 3B shows a further measurement setup according to the present disclosure, comprising: interferometer device (1), scanner (2), interferometer device (1) emitting a light beam (3) toward the outer surface of a hollow body (4), second interferometer device (1'), second scanner (2'), second interferometer device (1') emitting a second light beam (3') toward the outer surface of a hollow body (4), third interferometer device (1"), third scanner (2"), and third interferometer device (1") emitting a third light beam (3") toward the outer surface of a hollow body (4). The scanner (2, 2', 2") can change the axis of the light beam (3, 3', 3") so that the light beam (3, 3', 3") may be substantially parallel to the corresponding diameter of the cross-section of the hollow body (4). Thus, reflected light (3 R , 3' R , 3” R ) reaches the interferometer device (1).

[0023] method In one embodiment, the present disclosure provides a method for measuring at least one cross-sectional dimension of a cylindrical hollow body, the hollow body having a wall surrounding the lumen, a longitudinal axis, an inner surface and an outer surface, and the method is -The step of providing a cylindrical hollow body, - The steps of guiding a light beam along a travel path from an interferometer device toward the outer surface of a hollow body such that at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently, - In an interferometer device, the steps include receiving a portion of the light reflected from the outer surface and receiving a portion of the light reflected from the inner surface along the travel path, - The step of obtaining at least one cross-sectional dimension of a hollow body based on interferometry of a portion of the light reflected from the outer surface and / or a portion of the light reflected from the inner surface, This method, - This method is characterized by including the step of changing the direction of the light beam's path toward the hollow body.

[0024] According to this disclosure, a cylindrical hollow body has walls surrounding a lumen, a longitudinal axis, an inner surface, and an outer surface. Theoretically, a cylindrical hollow body can take the form of a mathematically perfect cylinder. However, a cylindrical hollow body can have an overall cylindrical shape with technically acceptable deviations with respect to its inner diameter, its outer diameter, and the thickness of its walls along its length. A cylindrical hollow body may be a finite cylinder or may represent a part of a larger body, the part having the overall cylindrical shape with the technically acceptable deviations. The walls are to be understood as physical barriers of a certain wall thickness, and the physical barriers may be composed of different materials, such as glass or polymer. The lumen should be understood as an internal volume that can be evacuated, or filled with air, or filled with a gas mixture.

[0025] In one embodiment of this method, at least one cross-sectional dimension of the hollow body includes a first wall thickness (WT1), preferably an inner diameter (ID), more preferably a second wall thickness (WT2), and preferably an outer diameter (OD).

[0026] In one embodiment of this method, at least one cross-sectional dimension of the hollow body includes the outer diameter (OD).

[0027] Figure 1 is a cross-sectional view of a hollow body according to the present disclosure. An arbitrary diameter passing through the cross-section virtually cuts the hollow body across the left and right walls, which coincide with the first wall thickness (WT1) and the second wall thickness (WT2), from any viewpoint along the longitudinal axis. The imaginary intersections are labeled "10", "20", "30", and "40" along the path of the light beam. The distance between the intersections "20" and "30" of the diameters on the inner surface of the wall represents the inner diameter (ID). The distance between the intersections "10" and "40" of the diameters on the outer surface of the wall represents the outer diameter (OD). For a mathematically perfect cylinder, the outer diameter can be calculated as OD = WT1 + ID + WT2. However, according to the present disclosure, the outer diameter is accessible through measurements of a cylindrical hollow body having an overall cylindrical shape with technically acceptable deviations with respect to its inner diameter and the wall thickness along its length, and therefore the formula may not strictly match all real-world scenarios.

[0028] This method may rely on receiving a portion of the light reflected from the outer surface and receiving a portion of the light reflected from the inner surface along the movement path in an interferometer device in order to calculate the dimensions of at least one cross-section of the hollow body. If a sufficient portion of the reflected light is received from the first intersection "10" and the second intersection "20", the first wall thickness can be measured. If an even more sufficient portion of the reflected light is received from the third intersection "30", the inner diameter can be measured. If an even more sufficient portion of the reflected light is received from the fourth intersection "40", the second wall thickness and outer diameter can be measured.

[0029] This method may also rely on receiving a portion of the light reflected from the outer surface. For example, if the hollow body is filled with a medium whose refractive index is close to or matches that of the material of the hollow body, a sufficient portion of the reflected light can be received from the first intersection "10" and the fourth intersection "40", so that the outer diameter can be measured. Thus, this method makes it possible to measure vials filled with a water-glycerin solution containing, for example, one or more pharmaceutical ingredients and / or other ingredients of optional choice.

[0030] This method is advantageous because the step of changing the direction of the light beam's path toward the hollow body allows for the detection of a sufficient portion of the reflected light from any or all of the hypothetical intersections along the light beam's path, namely the first intersection "10", the second intersection "20", the third intersection "30", and the fourth intersection "40". Due to this feature, the probability of detecting a sufficient portion of the reflected light is higher compared to a static situation where the light beam's path toward the hollow body is permanent with respect to the reference frame of the interferometer device.

[0031] In one embodiment of this method, the hollow body is a glass tube or glass tube strand, and the glass tube or glass tube strand is optionally transported from a production line such as the Belo or Downdraw method or the Danner method in a direction substantially parallel to the longitudinal axis of the glass tube strand, and / or the glass tube or glass tube strand rotates around the longitudinal axis of the glass tube, and / or the glass tube moves parallel to the longitudinal axis of the glass tube.

[0032] In one embodiment, the hollow body is made from a glass tube, such as a vial, ampoule, or syringe. The glass tube may also be a cut portion of a glass tube. In one embodiment, the glass tube may have two open ends. In one embodiment, the glass tube may have two closed ends. In one embodiment, the glass tube may have one open end and one closed end.

[0033] In one embodiment, the hollow body is a glass tube strand that can be obtained from a manufacturing line such as the Belo or Downdraw method or the Danner method. In the manufacturing process, an "infinitely long" glass tube strand is drawn from the molten glass. Typically, after passing through a roller track and a subsequent pipe drawing machine, a glass tube portion can be obtained by cutting the glass tube strand. In the industrial production process, the glass tube portion is often about 1.5 m in length. The method according to this disclosure is applicable to glass tube strands before and / or after passing through the roller track and / or after passing through a subsequent pipe drawing machine.

[0034] The methods according to this disclosure may be performed on a fixed hollow body or a moving hollow body. The fixed hollow body may, for example, be firmly clamped or move relative to a reference frame of an interferometer device. Thus, glass tube portions, vials, ampoules and / or syringes may be measured when mounted or while moving, i.e., during translation or rotation. In one embodiment of the method, glass tube portions, vials, ampoules and / or syringes may rotate around their longitudinal axis. In one embodiment of the method, glass tube portions, vials, ampoules and / or syringes may be transported along their longitudinal axis. In one embodiment of the method, a glass tube strand rotates around its longitudinal axis. In one embodiment of the method, a glass tube strand is transported along its longitudinal axis.

[0035] The method according to this disclosure is also advantageous for measurements in a fixed setting, because unless the direction of the light beam's path toward the hollow body is changed, it is unlikely that the mounted glass tube or glass tube strand will be perfectly oriented to obtain a sufficient portion of the reflected light from the first intersection "10", the second intersection "20", preferably the third intersection "30", and preferably the fourth intersection "40". By changing the direction of the light beam's path toward the hollow body, the likelihood of detecting a sufficient portion of the reflected light from the virtual intersections increases. This feature reduces measurement time by eliminating the need for time-consuming adjustment of the sample or measuring device orientation.

[0036] In one embodiment of this method, the hollow body comprises or is composed of a glass composition or a polymer material, preferably the glass composition is transparent at a certain wavelength of the light beam or alternatively a wavelength range, and preferably the polymer material is transparent at a certain wavelength of the light beam or alternatively a wavelength range.

[0037] In this disclosure, the “transparent” glass composition and transparent polymer material each have a transmittance of at least 30% at at least one measurement wavelength within the wavelength range of, for example, 300 to 5000 nm, measured at the wall thickness (particularly WT1) of a cylindrical hollow body, and optionally have a transmittance haze value of less than 1.0%, where the transmittance haze value refers to the amount of light scattered at an angle greater than 2.5° from the normal, measured according to ASTM D 1003-13 (Procedure A - Haze Meter) using CIE Standard Emitting Object C. In alternative embodiments, the “transparent” glass composition and transparent polymer material each may have a transmittance of at least 50% or at least 70% with respect to at least one measurement wavelength, measured at the wall thickness (particularly WT1) of a cylindrical hollow body, and optionally have a transmittance haze value of less than 1.0%.

[0038] In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 30% in the wavelength range of 300 to 750 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 50% in the wavelength range of 300 to 750 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 70% in the wavelength range of 300 to 750 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 90% in the wavelength range of 300 to 750 nm when measured at a thickness of 1 mm.

[0039] In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 30% in the wavelength range of 750 to 2500 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 50% in the wavelength range of 750 to 2500 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 70% in the wavelength range of 750 to 2500 nm when measured at a thickness of 1 mm. In one embodiment, the glass composition or polymer material according to the disclosure has a transmittance of at least 90% in the wavelength range of 750 to 2500 nm when measured at a thickness of 1 mm.

[0040] In one embodiment, the hollow body has an outer and inner surface roughness of 1 nm to 5000 nm, or 10 nm to 3000 nm, or 50 nm to 2000 nm, or 70 nm to 1000 nm, or 100 nm to 500 nm, as measured according to ISO 25178-2:2012. In one embodiment, the hollow body has an outer and inner surface roughness of 1 nm or more, or 10 nm or more, or 50 nm or more, or 70 nm or more, or 100 nm or more. In one embodiment, the hollow body has an outer and inner surface roughness of 5000 nm or less, or 3000 nm or less, or 2000 nm or less, or 1000 nm or less, or 500 nm or less.

[0041] In one embodiment of this method, the light beam is a focused light beam focused on the outer surface of a hollow body, and the focused light beam preferably contains or consists of coherent monochromatic light. Advantageously, by using a focused light beam, greater intensity is provided when receiving portions of light reflected from the outer surface and portions of light reflected from the inner surface. Similarly, portions of reflected light received from the third intersection "30" and the fourth intersection "40" can be detected with greater intensity. This can increase the number of successful detection events.

[0042] In one embodiment of this method, the light beam is a collimated light beam. This option hypothetically provides that, ignoring absorption effects, equal portions of light can reach the first intersection "10", the second intersection "20", the third intersection "30", and the fourth intersection "40".

[0043] In one embodiment of this method, the light beam contains or is composed of coherent monochromatic light.

[0044] In one embodiment of this method, the step of guiding the light beam is performed by a scanner capable of operating at a mechanical scanning frequency of 10 Hz to 1000 Hz, preferably 200 Hz to 300 Hz, and / or the device is capable of operating at a data sampling frequency of up to 100 kHz, preferably 60 kHz to 70 kHz.

[0045] In one embodiment, the scanner operates in one dimension, and the scanner is mounted such that the vector of the light beam directed to the outer surface of the hollow body and the vector parallel to the longitudinal axis of the cylindrical hollow body are perpendicular to each other. This alignment ensures that during scanning, the light beam directed to the outer surface of the hollow body may align perpendicular to the longitudinal axis of the cylindrical hollow body, thereby enabling the reception of a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the movement path in the interferometer device.

[0046] In one embodiment, the scanner operates two-dimensionally. Two-dimensional scanning has the advantage that, in scanner mounting, a specific alignment of the light beam directed towards the outer surface of the hollow body is not required. Due to its nature, two-dimensional scanning ensures that, during scanning, the light beam directed towards the outer surface of the hollow body may align perpendicularly with the longitudinal axis of the cylindrical hollow body, thereby enabling the reception of a portion of the light reflected from the outer surface and a portion of the light reflected from the inner surface along the movement path in the interferometer device.

[0047] In one embodiment of the method, for each obtained value in the step of obtaining at least one cross-sectional dimension of the hollow body, a timestamp is recorded. Thereby, statistical data can be generated and further analyzed. For example, in a fixed situation where the hollow body is attached to a fixed position, such as a glass tube or a glass tube strand, several values of at least one cross-sectional dimension, namely WT1, preferably ID, more preferably WT2, and OD, can be obtained along one and the same diagonal axis within the fixed cross-section of the hollow body. When the hollow body is rotated, for example, when a glass tube or a glass tube strand is rotated around the longitudinal axis of the glass tube, several values of WT1, preferably ID, WT2, and OD can be obtained for different diagonal axes within the fixed cross-section of the hollow body. When the glass tube or the glass tube strand is conveyed from a production line such as the Vello or the down-draw method, or the Danner method, in a direction substantially parallel to the longitudinal axis of the glass tube strand, and / or when the glass tube is translated parallel to the longitudinal axis of the glass tube, the individual values of at least one cross-sectional dimension, namely WT1, preferably ID, more preferably WT2, and OD, can be obtained from different cross-sections of the hollow body.

[0048] In one embodiment of the method where the hollow body is a glass tube or a glass tube strand, the conveyance of the glass tube proceeds at a speed of 0.001 - 6 ms -1 or 0.005 - 5 ms -1 or 0.01 - 4 ms -1 or 0.05 - 3 ms -1 or 0.1 - 2 ms -1 In one embodiment, the conveyance of the glass tube proceeds at a speed of 0.001 ms -1 or more, or 0.005 ms -1 or more, or 0.01 ms -1 or more, or 0.05 ms -1 or more, or 0.1 ms -1 In one embodiment, the conveyance of the glass tube proceeds at a speed of 6 ms -1 or less, or 5 ms -1 or less, or 4 ms -1 or less, or 3 ms -1 or less, or 2 ms-1 It will proceed at the following speed.

[0049] In one embodiment, the wall of the cylindrical hollow body has a thickness of 0.1 to 20.0 mm, or 0.2 to 10.0 mm, or 0.3 to 6.5 mm, or 0.5 to 4.0 mm, or 0.5 to 2.0 mm. The wall thickness of the cylindrical hollow body may be related to or coincide with the first wall thickness (WT1) and / or second wall thickness (WT2) of at least one cross-sectional dimension of the hollow body. In one embodiment, the wall thickness is 0.1 mm or more, or 0.2 mm or more, or 0.3 mm or more, or 0.5 mm or more. In one embodiment, the wall thickness is 20.0 mm or less, or 10.0 mm or less, or 6.5 mm or less, or 4.0 mm or less, or 2.0 mm or less.

[0050] In one embodiment, this method - The steps of guiding a second light beam from a second interferometer device toward the outer surface of a hollow body along a second movement path, and receiving in the second interferometer device a portion of the light reflected by another tangent plane on the outer surface and a portion of the light reflected by another tangent plane on the inner surface along the second movement path, and optionally, -The further step of guiding a third light beam from a third interferometer device toward the outer surface of a hollow body along a third movement path, and receiving in the third interferometer device a portion of the light reflected by yet another tangent plane of the outer surface and a portion of the light reflected by yet another tangent plane of the inner surface along the third movement path.

[0051] Advantageously, by receiving a portion of the light reflected by three separate tangent planes on the outer surface and a portion of the light reflected by three separate tangent planes on the inner surface, it becomes possible to simultaneously detect the first wall thickness (WT1) at three separate locations on the hollow body. The hollow body has an inner cross section and an outer cross section, the inner cross section may be approximated as an inner ellipse, and the outer cross section may be approximated as an outer ellipse. The inner ellipse has an inner eccentricity. The outer ellipse has an outer eccentricity. According to this disclosure, the eccentricity e is calculated as follows: e=sqrt(1-(b 2 / a2 )), In the formula, a is the major axis of the ellipse and b is the minor axis. This configuration makes it possible to estimate and / or measure the eccentricity e, as well as the lengths of the major axis a and minor axis b, for both the inner and outer ellipses of the hollow body.

[0052] In one embodiment, this method - The steps of guiding a fourth light beam from a fourth interferometer device toward the outer surface of a hollow body along a fourth movement path, and receiving a portion of the light reflected by further tangent planes on the outer surface and a portion of the light reflected by further tangent planes on the inner surface along the fourth movement path in the fourth interferometer device, -The further step of guiding a fifth light beam from a fifth interferometer device toward the outer surface of a hollow body along a fifth movement path, and receiving in the fifth interferometer device a portion of the light reflected by yet another tangent plane of the outer surface and a portion of the light reflected by yet another tangent plane of the inner surface along the fifth movement path.

[0053] The possibility of simultaneously detecting the first wall thickness (WT1) at five distinct locations within the hollow body is further improved by the light-receiving portions of light reflected by five distinct tangent planes on the outer surface and five distinct tangent planes on the inner surface.

[0054] In one embodiment of this method, the movement path of the light beam directed towards the outer surface of the hollow body, the second movement path of the second light beam directed towards the outer surface of the hollow body, and the third movement path of the third light beam directed towards the outer surface of the hollow body lie in the same geometric plane.

[0055] In one embodiment of this method, the movement path of the light beam directed towards the outer surface of the hollow body, the second movement path of the second light beam directed towards the outer surface of the hollow body, and the third movement path of the third light beam directed towards the outer surface of the hollow body each lie in mutually exclusive geometric planes.

[0056] In one embodiment of this method, the movement path of the light beam directed towards the outer surface of the hollow body, the second movement path of the second light beam directed towards the outer surface of the hollow body, the third movement path of the third light beam directed towards the outer surface of the hollow body, the fourth movement path of the fourth light beam directed towards the outer surface of the hollow body, and the fifth movement path of the fifth light beam directed towards the outer surface of the hollow body lie in the same geometric plane.

[0057] In one embodiment of this method, at least two of the following paths lie in the same geometric plane: the path of the light beam directed toward the outer surface of the hollow body, the second path of the second light beam directed toward the outer surface of the hollow body, the third path of the third light beam directed toward the outer surface of the hollow body, the fourth path of the fourth light beam directed toward the outer surface of the hollow body, and the fifth path of the fifth light beam directed toward the outer surface of the hollow body.

[0058] In one embodiment of this method, at least three of the following paths lie in the same geometric plane: the path of the light beam directed toward the outer surface of the hollow body, the second path of the second light beam directed toward the outer surface of the hollow body, the third path of the third light beam directed toward the outer surface of the hollow body, the fourth path of the fourth light beam directed toward the outer surface of the hollow body, and the fifth path of the fifth light beam directed toward the outer surface of the hollow body.

[0059] In one embodiment of this method, at least four of the following paths lie in the same geometric plane: the path of the light beam directed towards the outer surface of the hollow body, the second path of the second light beam directed towards the outer surface of the hollow body, the third path of the third light beam directed towards the outer surface of the hollow body, the fourth path of the fourth light beam directed towards the outer surface of the hollow body, and the fifth path of the fifth light beam directed towards the outer surface of the hollow body.

[0060] Device In a second aspect, the present disclosure provides an apparatus for measuring at least one cross-sectional dimension of a cylindrical hollow body, The apparatus comprises at least one interferometer device and a scanner, The scanner can be positioned to guide the synchrotron radiation beam from at least one interferometer device along a trajectory toward the outer surface of the hollow body. The device is characterized by its ability to change the direction of the synchrotron radiation beam's movement path using a scanner.

[0061] In related embodiments, the present disclosure provides an apparatus for measuring at least one cross-sectional dimension of a cylindrical hollow body. The apparatus comprises at least one interferometer device and a scanner, The scanner can be positioned to guide the synchrotron radiation beam from at least one interferometer device along a travel path toward the outer surface of the hollow body. The device is characterized in that the scanner is configured to change the direction of the movement path of the synchrotron radiation beam.

[0062] The disclosed apparatus solves the problems of the prior art and provides more reliable and robust measurements of cylindrical hollow bodies.

[0063] According to this disclosure, an interferometer device detects and analyzes the properties of a physical object, such as a hollow cylindrical body, through interference. For this purpose, in a single interferometer device, light from a single light source is split into two or more reflected beams traveling along different optical paths and then recombined to generate interference. Both coherent and incoherent light sources can be used. The resulting interference pattern makes it possible to access the geometric properties of the investigated physical object.

[0064] According to this disclosure, the scanner is an element that can realize a change in beam direction over a specific angular range along the measurement axis. The scanner does not provide beam expansion. The measurement axis of the interferometer device is swept by the scanner over a relevant angular range relative to the cylindrical hollow body. When the measurement axis strikes the outer surface of the hollow body, a portion of the light reflected from the outer surface is received, and a portion of the light reflected from the inner surface can be received along the moving path of the interferometer device. From these two portions of light reflected from the outer surface and the inner surface, a measurement of the first wall thickness (WT1) can be obtained.

[0065] In one embodiment, the scanner is selected from a list of piezoelectric scanners, galvanometer scanners, prism scanners, and MEMS mirror scanners. The scanner can be selected to provide sufficient throughput for the measurements. In one embodiment, the scanner can operate at a mechanical scanning frequency of 10 Hz to 1000 Hz, preferably 200 Hz to 300 Hz. In one embodiment, the scanner can operate at a data sampling frequency of up to 100 kHz, preferably 60 kHz to 70 kHz.

[0066] In one embodiment, the interferometer device is a Fizeau interferometer, a Mach-Zehnder interferometer, a Michelson interferometer, or a Czerny-Turner spectrometer. Preferably, the interferometer device is a Czerny-Turner spectrometer.

[0067] In one embodiment, the apparatus further comprises a focusing means and / or the apparatus can be mounted in association with a conveying means suitable for conveying the cylindrical hollow body in a direction substantially parallel to the longitudinal axis of the cylindrical hollow body.

[0068] In one embodiment, the focusing means is selected from a list of biconvex lenses, plano-convex lenses, cylindrical lenses, and composite lenses.

[0069] In one embodiment, the conveying means is selected from a list of rails, rollers, belts, and positioning frames.

[0070] In one embodiment, the apparatus further comprises a second interferometer device, a second scanner, and optionally a third interferometer device and a third scanner. The second interferometer device and the second scanner are functionally positioned in the same way as the interferometer device and scanner, with respect to another tangent plane on the outer surface of the hollow body. A third interferometer device and a third scanner, if present, are functionally positioned in relation to yet another tangent plane to the outer surface of the hollow body, similar to the interferometer device and scanner.

[0071] In one embodiment of the apparatus, the interferometer device, scanner, second interferometer device, second scanner, third interferometer device, and third scanner are arranged in a single geometric plane. This advantageous configuration provides that several data points, i.e., values, at one cross-sectional dimension of the cylindrical hollow body can be measured. Thus, this arrangement provides access to receive portions of light reflected by three distinct tangent planes on the outer surface and portions of light reflected by three distinct tangent planes on the inner surface, from which simultaneous detection of the first wall thickness (WT1) at three distinct locations of the hollow body can be performed. This arrangement makes it possible to estimate and / or measure the eccentricity e of the hollow body, as well as the lengths of the major axis a and minor axis b of both the inner and outer ellipses of the hollow body.

[0072] In one embodiment, an interferometer device, a scanner, a second interferometer device, a second scanner, a third interferometer device, and a third scanner are integrated into a single device, preferably the device according to this disclosure.

[0073] In one embodiment, the apparatus further comprises a fourth interferometer device, a fourth scanner, and optionally a fifth interferometer device and a fifth scanner. The fourth interferometer device and the fourth scanner are functionally positioned in the same way as the interferometer device and scanner, in relation to another tangent plane to the outer surface of the hollow body. The fifth interferometer device and fifth scanner, if present, are functionally positioned in relation to yet another tangent plane to the outer surface of the hollow body, similar to the interferometer device and scanner.

[0074] In one embodiment of the apparatus, an interferometer device, a scanner, a second interferometer device, a second scanner, a third interferometer device, a third scanner, a fourth interferometer device, a fourth scanner, a fifth interferometer device, and a fifth scanner are arranged in a single geometric plane.

[0075] In one embodiment, an interferometer device, a scanner, a second interferometer device, a second scanner, a third interferometer device, a third scanner, a fourth interferometer device, a fourth scanner, a fifth interferometer device, and a fifth scanner are integrated into a single device, preferably the device according to this disclosure.

[0076] cylindrical hollow body In a third aspect, the disclosure provides a cylindrical hollow body having a longitudinal axis, an outer surface and an inner surface, wherein the hollow body has a first wall thickness (WT1), an inner diameter (ID) and a second wall thickness (WT2), The first wall thickness (WT1), inner diameter (ID), and second wall thickness (WT2) can be measured along any straight line perpendicular to the longitudinal axis, where the straight line virtually cuts through the hollow body. The outer diameter (OD) of the hollow body is 6 mm or less. The inner diameter (ID) of the hollow body is 5 mm or less. The absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) is less than 0.01 mm, or less than 0.005 mm, or less than 0.003 mm, or less than 0.001 mm, and / or The inner diameter has a tolerance of less than 0.01 mm, less than 0.005 mm, less than 0.003 mm, or less than 0.001 mm.

[0077] The method described herein enables, for the first time, the measurement of small-diameter cylindrical hollow bodies, and thus allows for improved in-process control in the manufacture of such cylindrical hollow bodies.

[0078] According to this disclosure, the absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) may be evaluated for any pair of data along any straight line perpendicular to the longitudinal axis, where the straight line virtually cuts the hollow body at any point.

[0079] In one embodiment, the absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) is less than 0.01 mm, or less than 0.007 mm, or less than 0.005 mm, or less than 0.003 mm, or less than 0.001 mm. In one embodiment, the absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) is at least 0.00001 mm, or at least 0.0001 mm.

[0080] According to this disclosure, the tolerance of the inner diameter is evaluated with respect to an arbitrary straight line perpendicular to the longitudinal axis, which virtually cuts the hollow body at any point.

[0081] In one embodiment, the inner diameter has a tolerance of less than 0.01 mm, less than 0.007 mm, less than 0.005 mm, less than 0.003 mm, or less than 0.001 mm. In one embodiment, the inner diameter has a tolerance of at least 0.0001 mm.

[0082] In one embodiment, the hollow body has an inner cross-section and an outer cross-section, the inner cross-section may be approximated as an inner ellipse, and the outer cross-section may be approximated as an outer ellipse. The inner ellipse has an inner eccentricity of less than 0.1, or less than 0.03, or less than 0.01. The outer ellipse has an outer eccentricity of less than 0.1, or less than 0.03, or less than 0.01.

[0083] In one embodiment, the inner ellipse has an inner eccentricity of at least 0.0001, or at least 0.0003, or at least 0.001. In one embodiment, the inner ellipse has an inner eccentricity of 0.0001 to 0.1, or 0.0003 to 0.03, or 0.001 to 0.01.

[0084] In one embodiment, the outer ellipse has an outer eccentricity of at least 0.0001, or at least 0.0003, or at least 0.001. In one embodiment, the outer ellipse has an outer eccentricity of 0.0001 to 0.1, or 0.0003 to 0.03, or 0.001 to 0.01. [Examples]

[0085] Device The apparatus described herein was constructed using a Thorlabs scanner and scanner controller (GVS011), a standard Windows 10 PC system, Chrocodile Explorer 1.3.5 (Precitec) software, a TG120 (TTi) frequency generator, and a Chrocodile 2 IT 1300 (Precitec) interferometer.

[0086] method The apparatus was positioned around the glass tube production line immediately before the glass tubes were cut into single pieces. The apparatus was adjusted so that the laser beam passed through the longitudinal axis of the glass tube with the scanner in a neutral position, while the glass tube sections and transport means were positioned perpendicular to the laser beam. The measurement was then initiated.

[0087] measurement The dimensions of the glass tubes investigated were as follows (WT = wall thickness, OD = outer diameter): 1) WT = 0.30 mm and OD = 1.40 mm, 2) WT = 0.40 mm and OD = 1.25 mm, 3) WT = 0.50 mm and OD = 2.10 mm, 4) WT = 0.65 mm and OD = 1.85 mm, 5) WT = 0.77 mm and OD = 2.65 mm. The parameters that could be directly accessed were as follows: i) at least one of the wall thicknesses WT1 and / or WT2, ii) inner diameter (ID), iii) one of the inner diameter (ID) and wall thicknesses WT1 or WT2, iv) outer diameter (OD). The above parameters could be measured with a deviation of less than 0.005 mm from the actual value. The actual value of the inner diameter (ID) was measured using a gauge.

Claims

1. A method for measuring the dimensions of at least one cross-sectional area of ​​a cylindrical hollow body, wherein the hollow body has walls surrounding a lumen, a longitudinal axis, an inner surface and an outer surface, and the method is The steps include providing a cylindrical hollow body, The steps include: guiding the light beam along a travel path from an interferometer device toward the outer surface of the hollow body such that at least a portion of the light beam strikes the outer surface of the hollow body at least intermittently; The interferometer device includes the steps of receiving a portion of the light reflected from the outer surface and receiving a portion of the light reflected from the inner surface along the movement path, A step of obtaining at least one cross-sectional dimension of the hollow body based on interferometry of the portion of light reflected from the outer surface and / or the portion of light reflected from the inner surface, Includes, The method is characterized by including the step of changing the direction of the movement path of the light beam toward the hollow body, method.

2. The at least one cross-sectional dimension of the hollow body includes a first wall thickness (WT1), preferably an inner diameter (ID), more preferably a second wall thickness (WT2), and preferably an outer diameter (OD). The method according to claim 1.

3. The hollow body is a glass tube or a glass tube strand, and the glass tube or glass tube strand is optionally transported from a manufacturing line such as the Belo or Downdraw method or the Danner method in a direction substantially parallel to the longitudinal axis of the glass tube strand, and / or the glass tube or glass tube strand is rotated around the longitudinal axis of the glass tube, and / or the glass tube is moved parallel to the longitudinal axis of the glass tube. The method according to claim 1 or 2.

4. The hollow body comprises or is composed of a glass composition or a polymer material, preferably the glass composition is transparent at a certain wavelength of the light beam or alternatively in a wavelength range, and preferably the polymer material is transparent at a certain wavelength of the light beam or alternatively in a wavelength range. The method according to any one of claims 1 to 3.

5. The surface roughness of the outer and inner surfaces of the hollow body is measured in accordance with ISO 25178-2:2012 and is between 1 nm and 5000 nm, or between 10 nm and 3000 nm, or between 50 nm and 2000 nm, or between 70 nm and 1000 nm, or between 100 nm and 500 nm. The method according to any one of claims 1 to 4.

6. The light beam is a focused light beam concentrated on the outer surface of the hollow body, and the focused light beam preferably contains or is composed of coherent monochromatic light. The method according to any one of claims 1 to 5.

7. The step of directing the light beam is performed by a scanner capable of operating at a mechanical scanning frequency between 10 Hz and 1000 Hz, preferably between 200 Hz and 300 Hz, and / or the device is capable of operating at a data sampling frequency of up to 100 kHz, preferably between 60 kHz and 70 kHz. The method according to any one of claims 1 to 6.

8. The step of obtaining the at least one cross-sectional dimension of the hollow body involves recording a timestamp for each obtained value. The method according to any one of claims 1 to 7.

9. The transport of the glass tube is 0.001 to 6 ms －１ It proceeds at a speed between the above, The method according to claim 3.

10. The wall of the cylindrical hollow body has a thickness of 0.1 to 20.0 mm, or 0.2 to 10.0 mm, or 0.3 to 6.5 mm, or 0.5 to 4.0 mm. The method according to any one of claims 1 to 9.

11. The aforementioned method, The steps include: guiding a second light beam from a second interferometer device toward the outer surface of the hollow body along a second movement path, and receiving in the second interferometer device a portion of the light reflected by another tangent plane of the outer surface and a portion of the light reflected by another tangent plane of the inner surface along the second movement path; and optionally, The steps include: guiding a third light beam from a third interferometer device toward the outer surface of the hollow body along a third movement path; and receiving in the third interferometer device a portion of the light reflected by yet another tangent plane of the outer surface and a portion of the light reflected by yet another tangent plane of the inner surface along the third movement path; Further including, The method according to any one of claims 1 to 10.

12. An apparatus for measuring the dimensions of at least one cross-section of a cylindrical hollow body, The apparatus comprises at least one interferometer device and a scanner. The scanner can be positioned to guide the synchrotron radiation beam from at least one interferometer device along a travel path toward the outer surface of the hollow body, The scanner is characterized by being able to change the direction of the movement path of the synchrotron radiation beam. Device.

13. The scanner is selected from the list of piezoelectric scanners, galvanometer scanners, prism scanners, and MEMS mirror scanners, and / or the interferometer device is a Fizeau interferometer, a Mach-Zehnder interferometer, a Michelson interferometer, or a Czerny-Turner spectrometer, preferably the interferometer device is a Czerny-Turner spectrometer. The apparatus according to claim 12.

14. The apparatus further comprises a focusing means and / or the apparatus can be mounted in connection with a conveying means suitable for conveying a cylindrical hollow body in a direction substantially parallel to the longitudinal axis of the cylindrical hollow body. The apparatus according to claim 12 or 13.

15. The apparatus further comprises a second interferometer device, a second scanner, and optionally a third interferometer device and a third scanner. The second interferometer device and the second scanner are functionally arranged in relation to another tangent plane to the outer surface of the hollow body, in the same manner as the interferometer device and scanner described in claim 12. The third interferometer device and the third scanner, if present, are functionally arranged in relation to yet another tangent plane to the outer surface of the hollow body, in the same manner as the interferometer device and scanner described in claim 12. The apparatus according to any one of claims 12 to 14.

16. A cylindrical hollow body having a longitudinal axis, an outer surface and an inner surface, wherein the cylindrical hollow body has a first wall thickness (WT1), an inner diameter (ID) and a second wall thickness (WT2), The first wall thickness (WT1), the inner diameter (ID), and the second wall thickness (WT2) can be measured along any straight line perpendicular to the longitudinal axis, and the straight line virtually cuts the hollow body. The outer diameter (OD) of the hollow body is 6 mm or less. The inner diameter (ID) of the hollow body is 5 mm or less. The absolute difference between the first wall thickness (WT1) and the second wall thickness (WT2) is less than 0.01 mm, or less than 0.005 mm, or less than 0.003 mm, or less than 0.001 mm, and / or The inner diameter has a tolerance of less than 0.01 mm, less than 0.005 mm, less than 0.003 mm, or less than 0.001 mm. A cylindrical hollow body.

17. The hollow body has an inner cross-section and an outer cross-section, the inner cross-section may be approximated as an inner ellipse, and the outer cross-section may be approximated as an outer ellipse. The inner ellipse has an inner eccentricity of less than 0.1, or less than 0.03, or less than 0.

01. The outer ellipse has an outer eccentricity of less than 0.1, or less than 0.03, or less than 0.

01. The hollow body according to claim 16.

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