Bottle breakage detection method for rotary bottle blowing machine and rotary bottle blowing machine

Abstract

The present application belongs to the technical field of broken bottle detection, and discloses a broken bottle detection method of a rotary bottle blowing machine and the rotary bottle blowing machine. In the broken bottle detection method of the rotary bottle blowing machine, the rotary bottle blowing machine comprises a rotating disc, a plurality of mold frames and a plurality of bottle blowing units, the plurality of mold frames are uniformly and spacedly distributed along the circumference of the rotating disc, the bottle blowing units are located on the mold frames, the mold frames and the bottle blowing units are in one-to-one correspondence, the included angle between the two adjacent groups of mold frames is a mold included angle α, the rotating disc rotates, and the bottle blowing units are driven by the mold frames to sequentially perform a main blowing process and a broken bottle detection process, a main blowing angle and a broken bottle detection angle are the central angles of the rotating disc when the rotating disc rotates in the main blowing process and the broken bottle detection process, respectively, the interval between the upper limit angle and the lower limit angle of the broken bottle detection angle is 10°, and the interval angle D between the upper limit angle of the main blowing angle and the lower limit angle of the broken bottle detection angle is greater than m×α, wherein 1.5≤m≤2. The broken bottle detection method of the rotary bottle blowing machine can make the empty bottle unit have good forming quality and high broken bottle detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of bottle breakage detection technology, and in particular to a method for detecting bottle breakage in a rotary blow molding machine and the rotary blow molding machine itself. Background Technology

[0002] Rotary blow molding machines rely on a multi-station continuous rotation of a turntable to sequentially complete processes such as preheating and stretching of the preform, pre-blowing, main blowing, pressure holding and cooling, broken bottle detection, and venting. With its advantages of continuous operation and high capacity, it is widely used in the large-scale production of PET and PP plastic bottles. The broken bottle detection process identifies broken bottles and removes them via a rejection mechanism, preventing downtime caused by jamming of the blow molding machine's output star wheel.

[0003] In existing rotary blow molding processes, the angles (central angles of the turntable's rotation) between the main blow molding and broken bottle detection processes are not properly matched, resulting in poor bottle molding quality and low accuracy in broken bottle detection. For example, the broken bottle detection angle range is unreasonable, or the interval between the main blow molding angle and the broken bottle detection angle cannot be controlled based on the number of mold frames on the turntable. If the broken bottle detection angle is too small, the detection time cannot be guaranteed, easily leading to missed detections; if the broken bottle detection angle is too large, it will encroach on the angles of other processes. When the interval between the main blow molding angle and the broken bottle detection angle is too small, problems such as insufficient bottle pressure holding and cooling, incomplete venting of high-pressure gas inside the mold, and bottle instability after mold opening will occur, easily leading to misjudgments, incorrect rejection of good products, and missed detection of broken bottles. When the interval angle is too large, it will occupy the limited turntable station angle resources, compressing the effective detection angle, resulting in insufficient detection time under high-speed production conditions. At the same time, thin-walled bottles and tall bottles are prone to deformation due to their own weight when suspended for a long time, further aggravating detection errors and limiting the maximum capacity of the equipment.

[0004] Therefore, there is an urgent need to propose a method for detecting broken bottles in a rotary blow molding machine and a rotary blow molding machine in order to solve the above problems. Summary of the Invention

[0005] The first objective of this invention is to provide a method for detecting broken bottles in a rotary blow molding machine, which enables the empty bottle unit to have good forming quality and high accuracy in detecting broken bottles.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for detecting bottle breakage in a rotary blow molding machine, the rotary blow molding machine comprising a turntable, multiple mold frames, and multiple blow molding units, wherein the multiple mold frames are evenly spaced along the circumference of the turntable, the blow molding units are located on the mold frames, and there is a one-to-one correspondence between the mold frames and the blow molding units, the included angle between two adjacent sets of mold frames is the mold angle α, and the method for detecting bottle breakage in the rotary blow molding machine includes: The turntable rotates, driving the blow molding unit to perform the main blowing process and the bottle breakage detection process sequentially through the mold frame. The main blowing angle and the bottle breakage detection angle are the central angles through which the turntable rotates during the main blowing process and the bottle breakage detection process, respectively. The interval between the upper limit angle and the lower limit angle of the bottle breakage detection angle is 10°. The interval angle D between the upper limit angle of the main blowing angle and the lower limit angle of the bottle breakage detection angle is greater than m×α, where 1.5≤m≤2.

[0007] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the blow molding unit is equipped with a pressure sensor. The pressure sensor is used to detect pressure changes during the blow molding process. The blow molding pressure value in the main blow molding process is M bar, and the blow molding pressure alarm value in the bottle breakage detection process is (Mn) bar, where 1.5≤n≤2.

[0008] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the bottle breakage detection method of the rotary blow molding machine further includes a pre-blowing process, wherein the pre-blowing angle is the central angle through which the turntable rotates during the pre-blowing process, and the upper limit angle of the pre-blowing angle is equal to the lower limit angle of the main blowing angle.

[0009] As an optional technical solution for detecting broken bottles in a rotary blow molding machine, the interval between the upper limit angle and the lower limit angle of the pre-blowing angle is B, and the interval between the upper limit angle and the lower limit angle of the main blowing angle is C, and B < C.

[0010] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the bottle breakage detection method of the rotary blow molding machine further includes a preparation process, wherein the preparation process, the pre-blowing process, the main blowing process and the bottle breakage detection process are arranged in sequence.

[0011] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the bottle breakage detection method of the rotary blow molding machine further includes a gas recovery process, which is used to recover blow molding gas. The preparation process, the pre-blowing process, the main blowing process, the bottle breakage detection process and the gas recovery process are arranged in sequence.

[0012] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the bottle breakage detection method of the rotary blow molding machine further includes an exhaust process, which is used to discharge the remaining gas in the blow molding unit. The preparation process, the pre-blowing process, the main blowing process, the bottle breakage detection process, the gas recovery process and the exhaust process are arranged in sequence.

[0013] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, the preparation angle, gas recovery angle, and exhaust angle are the central angles through which the turntable rotates during the preparation process, the gas recovery process, and the exhaust process, respectively. The interval between the upper limit angle and the lower limit angle of the preparation angle is A, the interval between the upper limit angle and the lower limit angle of the gas recovery angle is E, and the interval between the upper limit angle and the lower limit angle of the exhaust angle is F, and A+B+C+D+10°+E+F<360°.

[0014] As an optional technical solution for the bottle breakage detection method of a rotary blow molding machine, if the hourly production capacity of a single mold frame is X, then the time for each mold frame to complete one revolution is t=3600 / X, where t is in seconds.

[0015] The second objective of this invention is to provide a rotary blow molding machine that can produce high-quality empty bottle units and achieve high accuracy in broken bottle detection.

[0016] To achieve this objective, the present invention adopts the following technical solution: A rotary blow molding machine, wherein the rotary blow molding machine is capable of forming empty plastic bottles in one go using the aforementioned broken bottle detection method.

[0017] The beneficial effects of this invention are: In the broken bottle detection method of the rotary blow molding machine provided by the present invention, the blow molding unit performs the main blowing process and the broken bottle detection process in sequence. The main blowing process realizes the high-pressure film bonding and shaping of the blow molding unit; the broken bottle detection process is used to detect and reject broken bottles to prevent broken bottles from flowing into the next production stage.

[0018] Secondly, the interval between the upper and lower limits of the bottle breakage detection angle is 10°, which ensures the time available for bottle breakage detection while avoiding taking up time for other processes.

[0019] Furthermore, the interval angle D between the upper limit angle of the main blowing angle and the lower limit angle of the broken bottle detection angle is greater than m×α, and 1.5≤m≤2. The interval angle D is reasonably determined according to the mold angle α, which has strong universality. However, if the interval angle D is too small, the empty bottle unit will not be sufficiently pressure-held and water-cooled after the main blowing process, and the bottle body will be too soft. After the mold is opened, the bottle body is prone to collapse, bulge and deformation, which will lead to the wrong judgment of broken bottles and rejection. If the interval angle D is too large, it will squeeze the broken bottle detection angle, which will lead to insufficient detection time and ultimately result in missed detection. Attached Figure Description

[0020] Figure 1 This is a diagram showing the mold frame distribution on a rotary blow molding machine provided in an embodiment of the present invention; Figure 2 This refers to the angular distribution of each process in the bottle breakage detection method for a rotary blow molding machine provided in this embodiment of the invention.

[0021] In the picture: 100. Turntable; 200. Mold frame. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0023] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0026] This embodiment provides a method for detecting broken bottles in a rotary blow molding machine. This method can ensure good molding quality of empty bottle units and high accuracy in detecting broken bottles.

[0027] Specifically, such as Figure 1 and Figure 2As shown, in the bottle breakage detection method of this rotary blow molding machine, the rotary blow molding machine includes a turntable 100, multiple mold frames 200, and multiple blow molding units. The multiple mold frames 200 are evenly spaced along the circumference of the turntable 100. The blow molding units are located on the mold frames 200, and there is a one-to-one correspondence between the mold frames 200 and the blow molding units. The included angle between two adjacent sets of mold frames 200 is the mold angle α. The bottle breakage detection method of the rotary blow molding machine includes: The turntable 100 rotates, driving the blow molding unit to perform the main blowing process and the bottle breakage detection process in sequence through the mold frame 200. The main blowing angle and the bottle breakage detection angle are the central angles through which the turntable 100 rotates during the main blowing process and the bottle breakage detection process, respectively. The interval between the upper limit angle and the lower limit angle of the bottle breakage detection angle is 10°. The interval angle D between the upper limit angle of the main blowing angle and the lower limit angle of the bottle breakage detection angle is greater than m×α, where 1.5≤m≤2.

[0028] Based on the above design, the blow molding unit sequentially performs the main blow molding process and the broken bottle detection process. The main blow molding process achieves high-pressure film bonding and shaping of the blow molding unit; the broken bottle detection process is used to detect and reject broken bottles, preventing them from flowing into the next production stage. Secondly, the interval between the upper and lower limits of the broken bottle detection angle is 10°, which ensures sufficient time for broken bottle detection while avoiding taking up time from other processes. Furthermore, the interval angle D between the upper and lower limits of the main blow molding angle and the broken bottle detection angle is greater than m×α, and 1.5≤m≤2. The interval angle D is reasonably determined based on the mold clamping angle α (essentially based on the number of 200 mold frames), which has strong universality. However, if the interval angle D is too small, the empty bottle unit will not be sufficiently pressurized and water-cooled after the main blow molding process, resulting in a softer bottle body. After mold opening, the bottle body is prone to collapse, bulge, and deformation, leading to the false judgment of broken bottles being rejected. If the interval angle D is too large, it will encroach on the broken bottle detection angle, resulting in insufficient detection time and ultimately causing missed detection.

[0029] It should be noted that, for example, the number of mold frames 200 is N (N≥2), and the mold angle α=360° / N. In this embodiment, N=20, then the mold angle α=18°.

[0030] For example, the value of m can be 1.5, 1.7, 1.9, or 2, etc. If m is too small, that is, less than 1.5, the interval angle D is too small. After the main blowing process of the empty bottle unit is completed, there is not enough pressure holding and water cooling. The bottle body is too soft. After the mold is opened, the bottle body is prone to collapse, bulge and deformation, resulting in the wrong judgment of broken bottles being rejected. If m is too large, that is, greater than 2, the interval angle D is too large, which will squeeze the broken bottle detection angle, resulting in insufficient detection time and ultimately leading to missed detection.

[0031] Specifically, the blow molding unit is equipped with a pressure sensor, which is used to detect pressure changes during the blow molding process. If the blow molding pressure value in the main blow molding process is M bar, then the blow molding pressure alarm value in the bottle breakage detection process is (Mn) bar, where 1.5≤n≤2.

[0032] For example, the value of n can be 1.5, 1.7, 1.9, or 2, etc.

[0033] Assuming M=32 bar, the minimum alarm value for bottle breakage detection is 30 bar, and the maximum is 30.5 bar.

[0034] Optionally, the bottle breakage detection method for a rotary blow molding machine also includes a pre-blowing process. The pre-blowing angle is the central angle of the turntable after 100 degrees of rotation during the pre-blowing process, and the upper limit of the pre-blowing angle is equal to the lower limit of the main blowing angle. The pre-blowing process uses low-pressure gas to pre-expand the elongated empty bottle unit preform, preventing localized mold adhesion and thickness deviation; controlling the radial expansion position of the preform to center the bottle bottom and avoid uneven bottom thickness; and reserving internal space to facilitate uniform diffusion of high-pressure gas during the main blowing process. The upper limit of the pre-blowing angle is equal to the lower limit of the main blowing angle, meaning that the high-pressure gas transitions seamlessly into the main blowing process at the end of the pre-blowing process, preventing deformation of the empty bottle unit.

[0035] Specifically, the interval between the upper and lower limits of the pre-blowing angle is B, and the interval between the upper and lower limits of the main blowing angle is C, with B < C. The pre-blowing process involves instantaneous air intake after the stretching rod has descended to its final position, only performing preliminary radial expansion of the preform and aligning the bottle bottom; this process is short and takes little time. The main blowing process switches to high pressure, requiring the preform to be fully adhered to the mold cavity and continuously maintained under pressure for water cooling and shaping (pressure holding accounts for the majority of the angles in the main blowing process). Cooling determines the bottle wall thickness and shaping dimensions, necessitating sufficient allowance for cornering.

[0036] The bottle breakage detection method for this rotary blow molding machine also includes a preparation process, which consists of a preparation process, a pre-blowing process, a main blowing process, and a bottle breakage detection process, arranged sequentially. The preparation process includes tasks such as loading the preform with a robotic arm, mold closing, mold locking, and nozzle descent.

[0037] The bottle breakage detection method for this rotary blow molding machine also includes a gas recovery process. This process recovers the blow molding gas, and the preparation, pre-blowing, main blowing, bottle breakage detection, and gas recovery processes are sequentially arranged. The recovery process enables the recycling and reuse of the blow molding gas.

[0038] The bottle breakage detection method of this rotary blow molding machine also includes an exhaust process, which is used to remove the remaining gas in the blow molding unit. The preparation process, pre-blowing process, main blowing process, bottle breakage detection process, gas recovery process and exhaust process are set up in sequence.

[0039] The preparation angle, gas recovery angle, and exhaust angle are the central angles through which the turntable 100 rotates during the preparation, gas recovery, and exhaust processes, respectively. In this embodiment, the interval between the upper and lower limits of the preparation angle is A, the interval between the upper and lower limits of the gas recovery angle is E, and the interval between the upper and lower limits of the exhaust angle is F, and A+B+C+D+10°+E+F<360°. One rotation of the turntable 100 completes all processes, and the remaining angle range is used for processes such as disassembling the empty bottle unit.

[0040] Furthermore, if the upper limit angle of the main blowing angle is L=A+B+C, then when m=1.5, the earliest angle of the lower limit angle of the bottle breakage detection angle is V1=L+1.5α, and the corresponding upper limit angle of the bottle breakage detection angle is T1=V1+10°; when m=2, the earliest angle of the lower limit angle of the bottle breakage detection angle is V2=L+2α, and the corresponding upper limit angle of the bottle breakage detection angle is T2=V2+10°.

[0041] Furthermore, if the hourly production capacity of a single mold frame 200 is X, then the time for each mold frame 200 to complete one revolution is t = 3600 / X, where t is in seconds. Therefore, the earliest time for the lower limit of the bottle breakage detection process is X1 = t × V1 / 360°, and the corresponding upper limit time is Y1 = t × T1 / 360°; the latest time for the lower limit of the bottle breakage detection process is X2 = t × V2 / 360°, and the corresponding upper limit time is Y2 = t × T2 / 360°.

[0042] This embodiment also provides a rotary blow molding machine, which can produce high-quality empty bottle units and has a high accuracy rate in detecting broken bottles.

[0043] Specifically, this rotary blow molding machine can use the aforementioned broken bottle detection method to form empty plastic bottles in one go. Since the interval between the upper and lower limits of the broken bottle detection angle is 10°, it can ensure the time for broken bottle detection and avoid taking up time in other processes. The interval angle D between the upper limit of the main blowing angle and the lower limit of the broken bottle detection angle is greater than m×α. The interval angle D is reasonably determined according to the mold clamping angle α (which is essentially based on the number of mold frames 200). It has strong universality, and if the size range of the interval angle D is appropriate, it can accurately detect broken bottles and remove them.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting broken bottles in a rotary blow molding machine, characterized in that, The rotary blow molding machine includes a turntable (100), multiple mold frames (200), and multiple blow molding units. The multiple mold frames (200) are evenly spaced along the circumference of the turntable (100). The blow molding units are located on the mold frames (200), and each mold frame (200) corresponds to one blow molding unit. The included angle between two adjacent sets of mold frames (200) is the mold angle α. The bottle breakage detection method of the rotary blow molding machine includes: The turntable (100) rotates, and the blow molding unit is driven by the mold frame (200) to perform the main blowing process and the bottle breakage detection process in sequence. The main blowing angle and the bottle breakage detection angle are the central angles through which the turntable (100) rotates during the main blowing process and the bottle breakage detection process, respectively. The interval between the upper limit angle and the lower limit angle of the bottle breakage detection angle is 10°. The interval angle D between the upper limit angle of the main blowing angle and the lower limit angle of the bottle breakage detection angle is m×α, where 1.5≤m≤2.

2. The method for detecting broken bottles in a rotary blow molding machine according to claim 1, characterized in that, The blow molding unit is equipped with a pressure sensor, which is used to detect pressure changes during the blow molding process. The blow molding pressure value in the main blow molding process is M bar, and the blow molding pressure alarm value in the bottle breakage detection process is (Mn) bar, where 1.5≤n≤2.

3. The method for detecting broken bottles in a rotary blow molding machine according to claim 1, characterized in that, The bottle breakage detection method of the rotary blow molding machine also includes a pre-blowing process. The pre-blowing angle is the central angle through which the turntable (100) rotates during the pre-blowing process, and the upper limit angle of the pre-blowing angle is equal to the lower limit angle of the main blowing angle.

4. The method for detecting broken bottles in a rotary blow molding machine according to claim 3, characterized in that, The interval between the upper and lower limits of the pre-blowing angle is B, and the interval between the upper and lower limits of the main blowing angle is C, where B < C.

5. The method for detecting broken bottles in a rotary blow molding machine according to claim 3, characterized in that, The method for detecting broken bottles in a rotary blow molding machine also includes a preparation process, wherein the preparation process, the pre-blowing process, the main blowing process, and the broken bottle detection process are arranged sequentially.

6. The method for detecting broken bottles in a rotary blow molding machine according to claim 5, characterized in that, The method for detecting broken bottles in a rotary blow molding machine also includes a gas recovery process, which is used to recover blow molding gas. The preparation process, the pre-blowing process, the main blowing process, the broken bottle detection process, and the gas recovery process are arranged in sequence.

7. The method for detecting broken bottles in a rotary blow molding machine according to claim 6, characterized in that, The bottle breakage detection method of the rotary blow molding machine also includes an exhaust process, which is used to discharge the remaining gas in the blow molding unit. The preparation process, the pre-blowing process, the main blowing process, the bottle breakage detection process, the gas recovery process and the exhaust process are arranged in sequence.

8. The method for detecting broken bottles in a rotary blow molding machine according to claim 7, characterized in that, The preparation angle, gas recovery angle, and exhaust angle are the central angles through which the turntable (100) rotates during the preparation process, the gas recovery process, and the exhaust process, respectively. The interval between the upper limit angle and the lower limit angle of the preparation angle is A, the interval between the upper limit angle and the lower limit angle of the gas recovery angle is E, and the interval between the upper limit angle and the lower limit angle of the exhaust angle is F, and A+B+C+D+10°+E+F<360°.

9. The method for detecting broken bottles in a rotary blow molding machine according to claim 8, characterized in that, If the hourly production capacity of a single mold frame (200) is X, then the time for each mold frame (200) to complete one revolution is t = 3600 / X, where t is in seconds.

10. A rotary blow molding machine, characterized in that, The rotary blow molding machine can use the broken bottle detection method of the rotary blow molding machine according to any one of claims 1-9 to form empty plastic bottles in one go.

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