JP2005172607A - Method for inspecting internal pressure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely perform inspection of internal pressure of a bottle can with a cap which is filled with the content. <P>SOLUTION: In a state in which the bottle can 25 with the cap is in the erected attitude so that a space is formed in the inside of a metal cap side of the bottle can, the top surface part of the cap is forcibly excited by electromagnetic induction, and the internal pressure of the bottle can 25 with the cap is inspected on, the basis of echo sound from the top surface part of the cap at this time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal pressure inspection method suitable for inspecting the internal pressure of a so-called bottle can with a cap.

  Traditionally, low-acid beverages such as coffee with milk are filled in aluminum positive pressure cans (filled with liquid nitrogen) or steel negative pressure cans, sealed and sterilized by retort, and then put into a carton case made of corrugated paper. Packed and loaded on pallet. And after leaving the can packed in a carton case for about 7 days, a can internal pressure test is performed for each carton case by so-called percussion to check for leaks. This is because if there is a fine pinhole in the can, it will cause a slow leak, so even if the internal pressure of the can is measured immediately after filling, the internal pressure of the can will not change much before filling, and there will be no problem with the presence or absence of leakage. Because there is. In addition, when the content is a low-acid beverage, in general, after filling the can with the content, nitrogen gas is filled to prevent oxidation of the content.

By the way, as a means for inspecting the can internal pressure by the above-mentioned percussion, in a state where the can filled and sealed with the contents is in an upright posture so that a space is formed on the bottom side of the inside of the can, Of the bottom of this can, the central portion in the radial direction, which is a smooth surface, is forcibly excited by electromagnetic induction, and the peak frequency calculated by capturing the reverberation from the can at this time, and the preset can internal pressure value, A method for inspecting the internal pressure of the can based on the correlation with the peak frequency is known (see, for example, Patent Document 1).
JP 49-34376

Here, when inspecting the internal pressure of the can, the can bottom is forcedly excited with the can in the upright posture, and the can lid is wound around one opening of the cylindrical body that has been conventionally supplied. This is due to the so-called can configuration.
That is, the can lid is generally arranged on the can lid top plate, the opening piece partitioned on the can lid top plate by the score, and the tip of the can lid so as to overlap the center side of the can lid top plate. Therefore, it is difficult to forcibly excite the can lid by electromagnetic induction, and even if it can be forcibly excited, the internal pressure is reduced from the reverberation sound obtained at this time. Since it is difficult to specify, a smooth surface without the opening piece or the like is provided with the can in an upright posture so that a space is formed on the bottom side of the inside of the can. This is due to the forced excitation of the bottom of the can.
Such an internal pressure inspection method is similarly used for bottled cans with caps, for which demand has increased in recent years.

However, when the conventional internal pressure inspection method is applied to a bottle can with a cap, the internal pressure may not be inspected with high accuracy.
In other words, a bottle can with a cap having a two-piece structure consisting of a cap and a bottle can is obtained after the bottomed cylindrical body formed by drawing and ironing a metal plate is filled with the contents. A cap is screwed into the opening of the bottom cylindrical body, and the bottom of this type of bottle can is generally formed in a dome shape recessed inside the can body. In the dome-shaped can bottom, even if the internal pressure of the bottled can with the cap rises, a compressive force directed radially inward is mainly generated, so that it is difficult to bulge and deform outside the can body. Therefore, there is a problem that even if the internal pressure of the bottle can with the cap changes, the echo sound due to the forced excitation hardly changes, and it is difficult to perform a high-precision internal pressure inspection. In particular, it is difficult to inspect minute changes in internal pressure, and in some cases, a good can is judged as a defective can, and conversely, a defective can is judged as a good can.

  As a means for solving such a problem, a configuration in which the bottom of the bottle can is flattened is conceivable. However, in such a configuration, when the internal pressure of the can rises more than usual due to some factor, the can easily This causes a problem that the bottom portion bulges and deforms outside the can body, that is, a decrease in the pressure resistance of the bottle can, and is not an effective solution.

  Further, if the internal pressure of the bottle cans with caps is individually inspected one by one, the bottle cans with caps need to be in an inverted posture so that a space is formed inside the bottom side. However, in such an upright posture, the placement stability is poor due to the shape of the bottle can with the cap, so it is difficult to stably hold the upright posture, and therefore it is difficult to perform a highly accurate internal pressure test. There was a problem of being.

  This invention is made | formed in view of the said condition, and it aims at providing the internal pressure test | inspection method which can test | inspect the internal pressure of what is called a bottle with a cap with high precision.

In order to solve the above-described problems and achieve such an object, the present invention proposes the following means.
The invention according to claim 1 is provided such that a large-diameter barrel portion is connected to the upper end in the can axis direction of the barrel portion via a convex curved connecting portion that protrudes radially outward. A shoulder portion that gradually decreases in diameter as it goes upward in the axial direction, and a base portion that extends continuously upward in the can axial direction and that is connected to the upper end portion in the can axial direction of the shoulder portion. A cap body comprising a top surface portion that is a flat surface and a side surface portion that is substantially suspended from the outer peripheral edge of the top surface portion in a state where the bottle can formed with the male screw portion is filled with the contents; An internal pressure for inspecting an internal pressure of a bottle can with a cap having a configuration in which a cap having a liner disposed inside a surface portion is screwed to the male screw portion in a state where the liner is in close contact with the opening of the bottle can It is an inspection method, and a space is formed inside the base part side of the bottle can. In the state where the bottle can with the cap is in an upright posture, the top surface of the cap is forcibly excited by electromagnetic induction, and the internal pressure of the bottle can with the cap is determined based on the echo sound from the top surface of the cap. It is characterized by inspecting.

  In this internal pressure inspection method, the cap top surface portion, which is a flat surface, is forcibly excited by electromagnetic induction, so that a highly accurate internal pressure inspection can be realized. In other words, the cap top surface portion is a part that bulges and deforms relatively linearly with respect to the change in the internal pressure of the bottle can with the cap, and the tensile state also changes. It will change accurately. Therefore, it is possible to accurately grasp a highly accurate internal pressure test, particularly a minute change in internal pressure.

  In addition, a liner is disposed on the inner surface of the cap top surface portion, and since this liner and the opening of the bottle can are in close contact with each other, vibration generated in the cap when the cap top surface portion is forcibly excited. Is attenuated by the liner and can be prevented from propagating to the bottle can. Therefore, the reverberation sound obtained by the forced excitation can be mainly from the top of the cap, and a highly accurate internal pressure inspection can be realized.

  Furthermore, since the internal pressure of this can is inspected with the bottle can with cap in the above-mentioned upright posture, even when inspecting the internal pressure while transporting each bottle can with cap individually, the cap top surface portion is forced. When excited, this bottle can with a cap can be easily and stably held, and a highly accurate internal pressure test can be easily realized.

  The invention according to claim 2 is the internal pressure inspection method according to claim 1, wherein the cap body is formed of an aluminum alloy having a 0.2% proof stress of 200 MPa to 240 MPa, and the top surface of the cap has an outer diameter of 28 mm. It is formed to be 46 mm or less and has a thickness of 0.23 mm to 0.27 mm.

  In this internal pressure inspection method, even when the can internal pressure rises and the cap top surface portion bulges and deforms upward in the can axial direction, it is possible to reliably suppress plastic deformation due to this deformation, and the can internal pressure It becomes possible to change the reverberation sound accurately by the change of. Therefore, it is possible to accurately grasp a highly accurate internal pressure test, particularly a minute change in internal pressure.

  According to the internal pressure inspection method for a can according to the present invention, the internal pressure inspection of a bottle can with a cap can be performed with high accuracy.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an internal pressure inspection method and an internal pressure inspection apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of an internal pressure inspection apparatus according to the present invention.
The internal pressure inspection device (hereinafter simply referred to as “inspection device”) 1 includes a carry-in passage 2, an internal pressure inspection means 3, a discharge section 4, a carry-out passage 5, a discharge passage 6, and a control means 7. It is configured.

  The carry-in path 2, the carry-out path 5, and the discharge path 6 are each formed by, for example, a conveyor that rotates the endless belt 21 with a drive motor (not shown). In the illustrated example, the carry-in path 2 and the carry-out path 5 have the upper surface of the endless belt 21 moved from the left side to the right side in the figure, and the discharge path 6 has the upper surface of the endless belt 21 from the upper side to the lower side in the figure. Moved to.

  The evacuation unit 4 has a schematic configuration including a conveyance path made of, for example, a free roller on which the case 23 is arranged and conveyed, and an evacuation drive unit (not shown), and the evacuation drive unit is formed of an air cylinder, for example. The structure is supported so as to be able to advance and retreat with respect to the conveyance path. Further, the conveyance path is inclined from the high place to the low place from the upstream side to the downstream side in the conveyance direction, and the case 23 that has reached the conveyance path moves from left to right in FIG. 1 by its own weight. It is supposed to be. In the course of this movement, when it is determined that the internal pressure value in the case 23 is outside the proper range as will be described later, the case 23 is discharged from the discharge path 6 by the forward drive of the waste drive unit. Moved to.

  A case 23 made of cardboard, for example, is placed on the upstream side of the carry-in path 2 in the transport direction. In the case 23, for example, six bottled cans 25 with caps filled and sealed with products (contents) such as coffee with milk and low-acid beverages in the illustrated example, and in the direction crossing this direction 4 in total, that is, a total of 24 in 4 rows and 6 columns. In general, when these cans are positive pressure cans, they are filled with liquid nitrogen, and when the contents are low acid beverages, they are filled with nitrogen gas to prevent oxidation of the contents.

Here, the schematic configuration of the bottle can with cap will be described.
As shown in FIG. 2, the bottle can 25 with a cap has a schematic configuration including a bottle can 26 and a cap 27. Of these, the bottle can 26 is drawn into a metal plate made of aluminum, aluminum alloy, or steel. After the bottomed cylindrical body is formed by processing and ironing, the opening of the bottomed cylindrical body is subjected to neck-in processing, threading processing, curl portion forming processing, and the like.

  The bottle can 26 is connected to a large-diameter barrel portion 26a and a can-axis-direction upper end of the barrel portion 26a via a convexly curved connecting portion 26b that protrudes radially outward. A schematic configuration having a shoulder portion 26c that gradually decreases in diameter as it goes upward in the can axis direction, and a base portion 26d that is connected to the upper end portion in the can axis direction of the shoulder portion 26c and extends upward in the can axis direction Has been. The base portion 26d is formed with a male screw portion 26e, and the upper end portion in the can axis direction is a curled portion 26f that is turned outward in the radial direction.

The cap 27 includes a top surface portion 27a that is a flat surface, a cap body that includes a side surface portion 27b that is substantially suspended from the outer peripheral edge portion of the top surface portion 27a, and a liner 27c that is disposed inside the top surface portion 27a. It is set as the schematic structure which has these. The cap body is made of an aluminum alloy having a 0.2% proof stress of 200 MPa or more and 240 MPa or less, and the cap top surface portion 27a is formed with an outer diameter of 28 mm or more and 46 mm or less and a thickness of 0.23 mm or more. It is formed to be 0.27 mm or less.
The cap 27 is screwed to the male thread portion 26e of the bottle can base portion 26d in a state where the liner 27c of the cap 27 is in close contact with the curled portion 26f of the bottle can base portion 26d.

Here, the cap main body which consists of the top surface part 27a and the side part 27b is formed based on the rolling material which consists of 5000 series aluminum alloy or 3000 series aluminum alloy.
First, in the case of a rolled material made of a 5000 series aluminum alloy, Fe: 0.05% or more and 0.35% or less, Mn: 0.01% or more and 0.10% or less, Mg: 1.5% or more by weight% It contains 2.1% or less, Cr is regulated to 0.10% or less, and the balance is composed of Al and inevitable additives.

  In producing this rolled material, first, an aluminum material having the above composition is melted and cast into a slab, then the thickness is set to 6 mm by hot rolling, and then the thickness is set by cold rolling. After 2.5 mm, the first intermediate annealing is performed at a temperature of 450 ° C. in a continuous annealing furnace. Here, the intermediate annealing means that annealing is performed at a temperature of 300 ° C. to 450 ° C. for 1 hour to 10 hours in the case of batch-type annealing, and 400 ° C. to 590 in the case of annealing by a rapid heating method. An annealing treatment at a temperature of 1 ° C. or less for 1 second or more and 60 seconds or less.

  After the first intermediate annealing, cold rolling is performed again to a sheet thickness of, for example, 0.6 mm, and the second intermediate annealing is performed in the continuous annealing furnace in the same manner as described above. Is cold-rolled to a final thickness of 0.25 mm. Then, final temper annealing is performed on the plate material having a thickness of 0.25 mm to form a rolled material. Here, the final temper annealing refers to annealing at a temperature of 160 ° C. to 260 ° C., preferably 200 ° C. to 230 ° C. when the rolled material is a 5000 series aluminum material. In the case of annealing, the annealing treatment is performed for 1 hour or more and 10 hours or less, and in the case of the rapid heating method, the annealing treatment is performed for 1 second or more and 60 seconds or less.

  Next, in the case of a rolled material made of a 3000 series aluminum alloy, Si: 0.01% to 0.60%, Fe: 0.1% to 0.7%, and Cu: 0.01% by weight. %: 0.50% or less, Mn: 0.3% or more and 1.3% or less, Mg: 0.1% or more and 1.4% or less, with the balance being composed of Al and inevitable additives ing.

  In producing this rolled material, first, an aluminum material having the above composition is melted and cast into a slab, then the thickness is set to 6 mm by hot rolling, and then the thickness is set by cold rolling. After 2.5 mm, this is subjected to the first intermediate annealing at a temperature of 460 ° C. in a continuous annealing furnace. And after cold-rolling again and setting the plate thickness to 0.50 mm, for example, this is subjected to the second intermediate annealing in the above-described continuous annealing furnace in the same manner as described above, and then this is made up to a final plate thickness of 0.25 mm. Cold rolling. Then, final temper annealing is performed on the plate material having a thickness of 0.25 mm to form a rolled material. Here, the final temper annealing refers to annealing at 150 ° C. or more and 250 ° C. or less, preferably 190 ° C. or more and 230 ° C. or less when the rolled material is a 3000 series aluminum material, and is batch-type annealing. In this case, the annealing treatment is performed for 1 hour or more and 10 hours or less, and in the case of the rapid heating method, the annealing treatment is performed for 1 second or more and 60 seconds or less.

The rolled material formed as described above has a 0.2% proof stress of 200 MPa to 240 MPa for both 3000 series and 5000 series aluminum materials.
And the cap main body is formed by giving a punching process etc. to the rolling material formed as mentioned above, and the cap 27 is formed by arrange | positioning the liner 27c inside the cap top surface part 27a after that.

  All bottled cans 25 with caps configured as described above are accommodated in the case 23 in an upright posture so that a space 25a is formed inside the bottle can cap 26d side. In this upright posture, in the inside of the bottle can with cap 25, in the present embodiment, the above-described contents reach the position in the can axis direction above the connecting portion 26b of the bottle can in the can axis direction of the shoulder portion 26c. Filled up to the top.

As shown in FIG. 1, the internal pressure inspecting means 3 is arranged on the downstream side of the carry-in path 2, and the cap-equipped bottle can 25 in the case 23 that is carried on the carry-in path 2, with respect to the carrying direction. The internal pressures of the cans 25 (four in each example in the illustrated example) arranged continuously in the intersecting direction can be sequentially examined while the case 23 is being conveyed.
As shown in FIG. 3, the internal pressure inspecting means 3 includes a vibration unit 11 that forcibly excites the central portion in the radial direction of the cap top surface portion 27 a and a microphone that captures reverberation sound from the cap top surface portion 27 a by the vibration unit 11. 12 is provided. Four percussion instruments 13 are continuously arranged in a direction intersecting the transport direction. In FIG. 1, the percussion devices 13 are sequentially arranged from the upstream side to the downstream side in the transport direction from the upper side to the lower side of the paper surface. The position is shifted. That is, the connecting direction of the percussion instrument 13 and the direction orthogonal to the conveying direction have a predetermined angle, and this angle is determined by the microphone 12 from the cap top surface portion 27a of the can 25 located next to it. For example, it is determined by the conveyance speed of the case 23, the material and size of the cap 27, and the like so that the time interval does not pick up the reverberation sound.

  The vibration unit 11 is formed with a hole 11a penetrating through the direction along the upper surface of the carry-in path 2, and a microphone 12 is disposed substantially directly above the through hole 11a. ing. As a result, when the central portion of the cap top surface portion 27a is forcibly excited by electromagnetic induction by the vibration portion 11, the reverberant sound from the top surface portion 27a passes through the through-hole 11a of the vibration portion 11 and the microphone 12 It has come to reach.

  The echo sound of the cap top surface portion 27a obtained by the microphone 12 of the internal pressure inspection means 3 is transmitted to the control means 7 shown in FIG. 1, and the internal pressure value of the bottle can with cap 25 is calculated by the calculation part 7a of this control means 7. Then, the internal pressure value is transmitted to the pass / fail determination unit 7b, and the determination unit 7b determines whether or not the internal pressure value of the bottle can 25 with the cap is appropriate. Then, the determination result is transmitted to the control unit 7c, and here, a rejection driving unit (not shown) disposed in the rejection unit 4 is controlled. That is, when the pass / fail determination unit 7b determines that all the internal pressure values of the bottled cans 25 with caps in the case 23 are appropriate, the case 23 continues to be transported by the carry-in path 2 without driving the evacuation driving unit. After that, when it reaches the carry-out path 5 and is conveyed to the next process, and it is determined that even one of the bottled cans 25 with a cap in the case 23 has an internal pressure value outside the proper range, the evacuation drive unit is driven. The case 23 is moved onto the discharge path 6 and discharged.

The calculation unit 7a calculates a peak frequency from the reverberation sound obtained by the microphone 12, and based on the peak frequency and a correlation between a preset can internal pressure value and the peak frequency, The internal pressure value is calculated.
The pass / fail determination unit 7b compares the internal pressure value calculated by the calculation unit 7a with a preset appropriate internal pressure value, and fails if the calculated internal pressure value is not within the range of the appropriate internal pressure value. If it is within this range, it is determined that it is acceptable.

A method for inspecting the internal pressure of the bottle can with a cap using the internal pressure inspection apparatus configured as described above will be described.
First, the case 23 is transported by the carry-in path 2, and this case 23 is brought to the position where the internal pressure inspection means 3 disposed along the carry-in path 2. At this time, all the bottled cans 25 with caps housed in the case 23 are erect so that a space 25a is formed inside the cap part 26d side of these bottled cans 25 with caps as shown in FIG. It is a posture.

  And among the four bottle cans 25 with caps (hereinafter simply referred to as “frontmost cans 25”) continuously arranged in the direction crossing the transport direction at the most distal portion in the transport direction of the case 23. One of the four testers 13 reaches the arrangement position of the tester 13 located on the most upstream side in the conveying direction, and the cap top surface portion 27a is moved by electromagnetic induction by the vibration unit 11. Forced excitation. Then, the reverberant sound from the cap top surface portion 27 a at this time is captured by the microphone 12 through the hole 11 a formed in the excitation portion 11. Then, this reverberation sound is transmitted to the calculating part 7a of the control means 7, and a peak frequency is calculated by this calculating part 7a. Then, the internal pressure value of the bottle can with cap 25 is calculated based on the peak frequency and the correlation between the preset can internal pressure value and the peak frequency. Thereafter, the internal pressure value is transmitted to the pass / fail determination unit 7b. The determination unit 7b compares the transmitted can internal pressure value with a preset proper internal pressure value, and the can internal pressure value is within the range of the proper internal pressure value. It is determined whether or not there is.

While transporting the case 23 from the forced excitation to the determination of the can internal pressure value while maintaining the non-contact state, not only the remaining cans in the frontmost row of cans 25 but also the transport direction from this row By carrying out similarly for the cans 25 located on the upstream side, it is carried out for all bottled cans 25 with caps accommodated in the case 23.
If it is determined that even one of the bottled cans 25 with a cap is outside the range of the appropriate internal pressure value, the evacuation drive unit of the evacuation unit 4 is driven, and the case 23 is connected to the discharge path 6. The case 23 is discharged through the discharge path 6.
When it is determined that the internal pressure values of all bottled cans 25 with caps accommodated in the case 23 are within the appropriate range, the evacuation drive unit of the evacuation unit 4 is not driven, and the case 23 reaches the carry-out path 5. To the next process.

  As described above, according to the internal pressure inspection method and inspection apparatus according to the present embodiment, the cap top surface portion 27a having a flat surface is forcibly excited by electromagnetic induction, so that a highly accurate internal pressure inspection can be realized. . That is, the cap top surface portion 27a is a portion that bulges and deforms relatively linearly with respect to the change in the internal pressure of the bottle can 25 with the cap, and the tensile state also changes. As a result, the reverberation sound changes accurately. Therefore, it is possible to accurately grasp a highly accurate internal pressure test, particularly a minute change in internal pressure.

  Further, a liner 27c is disposed on the inner surface of the cap top surface portion 27a. Since the liner 27c and the upper end portion of the curled portion 26f of the bottle can base portion 26d are in close contact with each other, the cap top surface portion 27a is forcibly excited. The vibration generated at the time of the vibration is attenuated by the liner 27c, and the propagation to the bottle can 26 can be suppressed. Therefore, the reverberation sound obtained by the forced excitation can be mainly from the cap top surface portion 27a, and a highly accurate internal pressure inspection can be realized.

  Further, the cap body is formed of an aluminum alloy having a 0.2% proof stress of 200 MPa to 240 MPa, and the cap top surface portion 27a is formed to have an outer diameter of 28 mm to 46 mm and a thickness of 0.23 mm or more. Since it is formed to be 0.27 mm or less, even when the cap top surface portion 27a bulges and deforms upward in the can axis direction, it is possible to reliably suppress plastic deformation due to this deformation, and the can internal pressure It becomes possible to change the reverberation sound accurately by the change of.

For example, even if the cap body is formed of the aluminum alloy and the thickness of the cap top surface portion 27a is set in the above range, if the outer diameter of the cap top surface portion 27a is larger than 46 mm, the cap top surface portion is increased due to an increase in internal pressure. When the cap 27a bulges and deforms upward in the can axis direction, the cap top surface 27a may be plastically deformed even if the inner pressure value is appropriate. In this case, for example, after the retort process is performed and the bottled can 25 with the cap is left for about 7 days, when the internal pressure is inspected, the cap top surface portion 27a is plastically deformed. Even if the can 25 has a slow leak and the internal pressure value is smaller than the appropriate value, the amount of bulging deformation of the cap top surface portion 27a is maintained in a state where the internal pressure is within the appropriate range. The problem of judging a good can may occur.
On the contrary, if the outer diameter of the cap top surface portion 27a is smaller than 28 mm, the cap top surface portion 27a hardly bulges and deforms upward in the can axis direction even if the internal pressure rises, and the change of the reverberant sound according to the change of the internal pressure is caused. It becomes difficult to capture and it is difficult to conduct a highly accurate internal pressure test.
As described above, the cap main body is formed of the aluminum alloy and the thickness and outer diameter of the cap top surface portion 27a are set in the above ranges, thereby accurately grasping a highly accurate internal pressure test, in particular, a minute change in internal pressure. It becomes possible.

Even when the adjacent bottle cans 25 with caps in the case 23 come into contact with each other, the internal pressure of the bottle cans 25 with caps can be inspected with high accuracy.
That is, in the bottle can 25 with a cap, the abutting portion is the entire body portion 26a of the bottle can 26, and in some cases, in addition to this, the lower portion in the can axis direction of the connecting portion 26b. The contents are filled up to the upper part of the portion 26c in the can axis direction. Therefore, the vibration when the cap top surface portion 27a is forcibly excited propagates to the shoulder portion 26c via the bottle can base portion 26d, and the portion of the shoulder portion 26c where the upper surface of the filled contents is located. The vibration amplitude is attenuated by the contents when the vibration propagates to the surface. Thereby, it is possible to suppress the propagation of vibration to the adjacent bottle can 26 through the bottle can 26 to which the cap 27 is screwed, and the liner 27c of the cap 27 is the curled portion 26f of the bottle can base 26d. Combined with the close contact with the upper end, the reverberation sound obtained when forced excitation can be substantially limited to that from the cap top surface portion 27a, and the internal pressure of the bottle can 25 with the cap can be reduced. Inspection can be performed with high accuracy.

  Here, in order to verify the above-described effects, 63 types of caps are formed by changing the outer diameter of the top surface of the cap and the material of the cap body, and the bottle cans are adapted to each of these cap shapes. After forming and filling the contents into each of these bottle cans, a suitable cap is screwed to form a bottle can with a cap, and each bottle can with the cap is tested to evaluate perusal adequacy described later. Went. The results are shown in FIG.

Here, the 63 types of caps formed will be described.
Seven types of aluminum alloys having 0.2% proof stress of 180 MPa, 190 MPa, 200 MPa, 210 MPa, 230 MPa, 240 MPa, and 250 MPa were used. For each type of aluminum alloy, the outer diameter of the cap top surface portion was φ16 mm, φ20 mm, φ24 mm, Nine types of caps of φ28 mm, φ33 mm, φ38 mm, φ42 mm, φ46 mm, and φ48 mm were formed, so that a total of 63 types of caps were formed. In addition, the thickness of these cap top surfaces was set to about 0.25 mm.

  After the 63 types of bottle cans with caps configured as described above are formed, they are subjected to retort processing. And after making a hole in the trunk | drum of this bottle can and making can internal pressure equivalent to atmospheric pressure, an air supply needle is inserted in this hole. Then, with the bottle can with cap in an upright posture so that the cap faces upward in the can axis direction, the top surface of the cap is forcibly excited by electromagnetic induction, and the peak frequency is determined by capturing the reverberation at this time. calculate. Then, when air is supplied from the air supply needle and the can internal pressure is increased by 0.04 MPa, the peak frequency is calculated again, and the amount of change in the peak frequency before and after the internal pressure increase is calculated. It can be said that the smaller the change amount of the peak frequency, the smaller the change in internal pressure can be detected. Specifically, if the amount of change in the peak frequency is 520 Hz or more, it can be said that it generally has good percussion appropriateness.

  From FIG. 4, when the thickness of the cap top surface portion is about 0.25 mm, the cap body is formed of an aluminum alloy having a 0.2% proof stress of 200 MPa or more and 240 MPa or less, and the cap top surface portion outer diameter is 28 mm or more. If it was 46 mm or less, it was confirmed that when the internal pressure of the can was changed by 0.04 MPa, the peak frequency was changed by 520 Hz or more, and it was possible to have good punching suitability.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the method of inspecting the internal pressure of the cans 25 in a state where a plurality of bottle cans 25 with caps are packed in the case 23 has been described, but the internal pressure may be inspected while being individually conveyed one by one. Even in this case, the same effect as that of the above embodiment is obtained, and when the cap top surface portion 27a is forcibly excited, the bottle can with cap 25 can be easily and stably held. Highly accurate internal pressure inspection can be easily realized.

Moreover, although the 2 piece structure which consists of the cap 27 and the bottle can 26 was shown as the bottle can 25 with a measuring object, it is not restricted to this, The bottle can with a cap of 3 pieces structure which tightened the bottom cover Applicable.
Furthermore, in the said embodiment, the bottled can 25 with a cap is forcedly excited by electromagnetic induction action, the peak frequency calculated by catching the reverberation sound from the can 25 at this time, the preset can internal pressure value and the peak frequency Although the method of calculating the internal pressure value of the can on the basis of the correlation with the internal pressure and inspecting the internal pressure of the can from this value has been shown, the present invention is not limited to this. Based on the reverberation sound obtained by forcibly exciting the can 25 The present invention can be applied to any method for inspecting the can internal pressure. For example, instead of calculating the peak frequency from the reverberant sound, the area value of the digit value with respect to the frequency may be calculated, and the can internal pressure may be inspected based on the area value, and the can internal pressure value may not be calculated. In addition, it may be determined directly from the peak frequency or the area value whether or not the internal pressure of the can is appropriate.
Furthermore, the number of the bottles with caps 25 packed in the case 23 and the number of the testers 13 may be any.

  The internal pressure of the bottle with a cap filled with the contents can be inspected with high accuracy.

It is the schematic block diagram shown as one Embodiment of the inspection apparatus which concerns on this invention. It is an expanded sectional view of a case and a bottle can with a cap shown in FIG. It is an expanded sectional view which shows the case shown in FIG. 1, a bottle can with a cap, and a percussion instrument. It is a figure which shows the result of having formed the some bottle can with a cap from which the outer diameter of a cap top | upper surface part, and the material of a cap main body differ, and evaluating the punching appropriateness about these bottle cans with a cap.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal pressure inspection apparatus 2 Carry-in part (conveyance means)
DESCRIPTION OF SYMBOLS 11 Exciting part 12 Microphone 13 Tester 23 Case 25 Cap can with bottle 25a Space 26 Bottle can 26a Body part 26b Connection part 26c Shoulder part 26d Base part 26e Male thread part 27 Cap 27a Top part 27b Side part 27c Liner

Claims (2)

A large-diameter barrel is connected to the upper end of the barrel in the can axis direction via a connecting portion having a curved surface that is convex outward in the radial direction, and gradually contracts toward the upper side of the can axis. A bottle can having a diameter shoulder portion, a base portion extending in the can axis direction of the shoulder portion, and a base portion extending upward in the can axis direction, and having a male screw portion formed in the base portion In the state where the contents are filled, a cap body comprising a top surface portion which is a flat surface, and a side surface portion substantially hanging from the outer peripheral edge portion of the top surface portion, and disposed inside the top surface portion. An internal pressure inspection method for inspecting an internal pressure of a bottle can with a cap having a configuration in which a cap having a liner is screwed to the male screw portion in a state where the liner is in close contact with an opening of the bottle can,
In a state where the bottle can with a cap is in an upright posture so that a space is formed inside the base portion of the bottle can,
An internal pressure inspection method, wherein the cap top surface portion is forcibly excited by electromagnetic induction, and the internal pressure of the bottle can with the cap is inspected based on echo sound from the cap top surface portion at this time. The internal pressure inspection method according to claim 1,
The cap body is formed of an aluminum alloy having a 0.2% proof stress of 200 MPa to 240 MPa,
The cap top surface portion is formed with an outer diameter of 28 mm or greater and 46 mm or less, and is formed with a thickness of 0.23 mm or greater and 0.27 mm or less.

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