JP3808070B2 - Internal pressure inspection device for canned food - Google Patents

Description

  The present invention relates to a canned internal pressure inspection device in which a can lid is fixed and sealed to a can body having no seam portion (joint portion) on its side surface, such as a two-piece can body, particularly when the can body is pressed. The present invention relates to an improvement in a canned internal pressure inspection device that estimates the canned internal pressure from force.

Normally, the can is in a state in which the contents are sealed, and invasion of bacteria from the outside or invasion of oxygen that oxidizes the contents is prevented, and the contents can be stored for a long period of time.
However, if there are fine holes in the can wall, or if there is a poorly tightened part, not only the leakage of the contents will be a problem, but also the storage stability will be greatly impaired, Detection is necessary.

In general, cans that are not sufficiently sealed are called leak cans, and various methods have been devised to detect them. A typical method is an internal pressure inspection method for cans.
In other words, canned foods are negative pressure canned (negative pressure canned food) that keeps the internal pressure in a reduced pressure state and easy to detect expansion in the case of content alteration, positive pressure canned food (positive pressure) in which the internal pressure of the carbonated beverage is in a pressurized state Canned).

Here, regarding positive pressure canning, for example, as shown in Patent Document 1 or Patent Document 2, the can is passed between two rollers set to be narrower than the diameter of the can body, and both rollers There is one that detects the internal pressure of a can by measuring the reaction force of the can when the can passes between them.
JP 62-162937 A Japanese Patent Publication No. 63-15538

The can internal pressure inspection method disclosed in Patent Document 1 is an excellent method in that the internal pressure of positive pressure canned food can be directly detected. On the other hand, an error is detected in the detected internal pressure value due to variations in the barrel diameter of the can. There was a problem that occurred.
That is, cans of the same type of can have basically the same circumferential length, but the shape is not necessarily a perfect circle. If it faces the measuring roller, the internal pressure is judged to be low, while if the major axis direction faces the internal pressure measuring roller, the internal pressure is judged to be high, and an error occurs in the detected internal pressure value even if it is the same can.

  In this regard, the technique disclosed in Patent Document 2 pays consideration to the variation in the diameter of the can body, but the can body is rotated on the process of pressing the same portion of the can body with different pushing amounts. A side holding belt or the like that is transported without being required is required, and the configuration is complicated, high-speed processing is difficult, the can body is easily damaged, and there is still room for improvement.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a can internal pressure inspection device capable of performing an accurate can internal pressure inspection of cans regardless of some errors in the can body diameter. There is.

In order to achieve the above object, an internal pressure inspection apparatus for canned food according to the present invention has an elastically deformable body wall, and the internal pressure inspection apparatus for a beverage can in which a can lid is fixed to a beverage can of a thin-walled can body. A first measuring unit, a second measuring unit, and a drive unit, and the first measuring unit and the first measuring unit according to a rotational speed difference (angle difference) of the other roller with respect to one roller of the first measuring unit The relative angle difference in the radial direction between the two measuring means is 90 ° ± 30 °.
Here, the conveyor places and transports canned goods to be inspected.
The first measuring means and the second measuring means are arranged on both sides of the conveyor so as to face each other at a distance narrower than the diameter of the canned food. A pair of rollers that press inward in the diametrical direction and a detection unit that measures the reaction force of the pressed canned food are arranged at predetermined intervals along the moving direction of the conveyor.
The driving section rotates the pair of rollers of the first measuring means at different peripheral speeds to rotate the canned food.

  As described above, according to the internal pressure inspection apparatus for canned food according to the present invention, the first measuring means and the second measuring means are provided, and the measuring diameter direction of the canned goods to be inspected by each measuring means is different, so that the can Even when the barrel is deformed, it is possible to measure the canned internal pressure with high accuracy and accuracy.

  Further, the accuracy can be particularly improved by setting the angle difference in the diameter direction measured by the first measuring means and the second measuring means to 90 degrees ± 30 degrees.

  Further, the first measuring means includes a pair of rollers that press the canned object to be inspected, and by making the peripheral speeds of the pair of rollers of the measuring means different, a highly accurate internal pressure inspection can be performed with a simple configuration. It becomes possible.

  The internal pressure inspection apparatus for canned food according to the present invention measures the pressing reaction force of the same canned can body from two different radial directions (or diameter directions) by the first and second measuring means as described above. As a result, even when the can body is deformed and has a major axis and a minor axis, it is possible to reduce the error when measuring the pressure reaction force only in the minor axis direction or only in the major axis direction. Can be greatly improved.

  In particular, considering the case where the can body is deformed into an ellipse, the relative angle in the radial direction between the first measuring means and the second measuring means is set to 90 degrees, and the average of the measured values is substantially obtained. Moreover, the measurement result of the pressing reaction force equivalent to the case where the can body is a perfect circle can be obtained.

  In addition, since it is possible to suppress variation in measurement results that is practically sufficient at about 90 ° ± 30 °, even if the rotation of the can body is slightly deviated, measurement accuracy is not greatly affected, and high-speed processing is possible. In this respect, unlike the technique disclosed in Japanese Examined Patent Publication No. 63-15538, which does not measure the pressure reaction force at the same position but rather increases the measurement error, the present invention is a highly realistic canned product. It can be said that this is an internal pressure inspection method.

  In addition, there is a technique described in Japanese Patent Publication No. 6-50280 as a technique that includes a first measuring means and a second measuring means, and rotates the inspected can between the two measuring means. In order to eliminate the error that occurs when one of the measuring means corresponds to the side seam part peculiar to the trunk, a low reaction force is adopted from the detection results of both measuring means. The present invention is basically different from the present invention in which the can obtained by fixing the can lid to the can body that does not have the can is to be inspected, and taking the average of the detection results of both detection means.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a partially broken front view of a can internal pressure inspection apparatus according to an embodiment of the present invention.
In the figure, the first measuring means 10 is mainly shown. The first measuring means 10 shown in the figure is opposed to both sides of the can 12 to be inspected and is spaced at a narrower distance than the diameter of the can 10 to be inspected. A pair of rollers 14a and 14b arranged, and a detection unit 16a (only the detection unit on the roller 14a side is illustrated) for detecting a pressing force in a direction separating the rollers 14a and 14b are provided. Further, the rollers 14a and 14b of the first measuring means 10 are rotationally driven at respective predetermined speeds by drive motors 18a and 18b disposed on the top thereof.

Then, the can 12 to be inspected is conveyed in the upright or inverted state by the belt conveyor 20 in the depth direction of the drawing in the drawing, and after passing through the first measuring means 10, the second measuring means having the same configuration. Enter.
Here, the configuration of the first measuring means 10 will be described in more detail.

  In the present embodiment, the rollers 14a and 14b are rotatably supported by roller holding frames 22a and 22b, respectively, and the drive motors 18a and 18b are supported on the upper portions of the holding frames 22a and 22b via columns 24a and 24b. Is supported. The rotation shafts of the drive motors 18a and 18b are connected to the upper support shafts of the rollers 14a and 14b via pipe-like transmission members 26a and 26b, respectively, and are eccentrically applied to the rollers 14 by interposing these transmission members 26. The force is reduced from becoming a load on the motor 18.

On the other hand, the holding frame 22a applies a load required to hold the posture to the support block 32a via a pressing force transmission rod 28a and a cylindrical support portion 30a that closely supports the rod 28a. Further, the left end 34a of the rod 28a in the drawing (FIG. 1) is connected to the pressing force detector 16a, and only the pressing force in the left direction in the drawing (FIG. 1) applied to the roller 14a passes through the rod 28a. And detected by the detector 16a.
Although not shown in the drawing, the right side portion of FIG. 1 is also provided with a pressing force transmission rod 28b, a cylindrical support portion 30b, a support block 32b, and a pressing force detection portion 16b, respectively, as in the left side portion. Yes.

  The support blocks 32a and 32b are suspended and supported by a support bridge 36 so as to be slidable in the left-right direction in the figure, and the gap between the rollers 14a and 14b is narrower by 1 to several mm than the standard can body diameter of the can 12 to be inspected. The blocks 32a and 32b are positioned and fixed so as to be in a state. That is, bolts 38a and 38b are screwed and fixed to both sides of the support bridge 36, and arms 40a and 40b extend downward from the bolts 38a and 38b, respectively. The lower ends of the arms 40a and 40b are connected to the support blocks 32a and 32b via bolts 42a and 42b, respectively. Therefore, the blocks 32a and 32b can be fixed to any widened position with respect to the support bridge 36 by changing the relative fixing positions of the arms 40a and 40b and the bolts 38a, 38b, 42a and 42b.

FIG. 2 is a conceptual diagram of the canned internal pressure inspection apparatus according to the present embodiment as viewed from above.
In the figure, the to-be-inspected can 12 is moving in the right direction together with the belt conveyor. First, the reaction force is measured by the first measuring means 10 shown in FIG. 1, and then the reaction force is measured again by the second measuring means 50 configured similarly to the first measuring means 10.

  The characteristic of the present invention is that the second measuring means presses the diameter direction different from that of the first measuring means and measures the reaction force of the canned object to be inspected. The rotational speed of the roller 14a of the measuring means is made larger than the rotational speed of the roll 14b.

  As a result, the inspected can 12 that has entered the first measuring means 10 is not only transported in the right direction by the rollers 14a and 14b, but also rotated in the direction of the arrow A during transport and discharged from the first measuring means 10. In the step of entering the second measuring means 50, the diameter direction arrow C different from the diameter direction arrow B when the reaction force is measured by the first measuring means 10 is set to the roller of the second measuring means 50. 54a and 54b.

Since the rollers 54a and 54b rotate at the same peripheral speed, the can measured by the second measuring means 50 is pressed in a diameter direction different from that of the first measuring means 10, and the reaction force is measured. The Rukoto.
The can pressing reaction force measured by the first measuring means 10 and the second measuring means 50 is sent to the calculating means 100 and averaged by the averaging unit 102. Then, the internal pressure calculation unit 104 calculates the canned internal pressure from the relationship diagram between the canning pressing reaction force and the canned internal pressure obtained in advance from the average value, and the determination unit 106 compares the internal pressure of the inspected canned food with the reference value. Judge the suitability.

As a result of processing by the calculation means 100, if it is determined that the inspected can 12 does not have an appropriate internal pressure, a removal signal for the can is sent to the removal means 110, and the defective can is removed from the conveyor 20. Is done.
As described above, according to the internal pressure inspection apparatus for canned goods according to the present embodiment, even when the can body is not a perfect circle such as an elliptical shape or a pear shape, the pressure reaction force is measured in two different diameter directions. The influence of the can body shape on the average pressing reaction force is extremely small.

In the present embodiment, the difference in the reaction force measurement diameter direction of the inspected can in the first measurement means and the second measurement means is determined by the difference in the relative angular velocities of the opposing rollers of the first measurement means. Although the canned product is obtained by rotating it, the present invention is not limited to this. For example, the following effects can be obtained by the following means.
(1) The relative angular velocities of the pair of rollers of the second measuring means are made different.
(2) The relative angular velocities of the respective roller pairs of the first measuring means and the second measuring means are made different.
(3) A can rotating mechanism such as a roller is provided between the first measuring means and the second measuring means.
(4) Apply resistance to one of the measuring means so as not to rotate, and rotate only the other roller.

  FIG. 3 shows the detection result of the canned internal pressure inspection apparatus according to the present invention and the detection result of the conventional apparatus.

In the same figure, (a) shows that the internal pressure produced by filling a 250 g tin-drawn squeezed tin can with a predetermined amount of water, immediately adding a predetermined amount of liquid nitrogen, and immediately sealing with a can lid is about 1. Using a can of 7 kg / cm ² , the same internal pressure measurement was performed only by the first measuring means (pressing the can body with a pair of opposing pressing rollers and measuring the reaction force) according to the prior art. Shows the average value and variation (standard deviation) of the detection output (digit value) when it is repeated, and the same canned product is measured (however, the pressing location of the pair of pressing rollers is different each time Despite this, the variation is very large.

  On the other hand, FIG. 5B shows the same canned product as measured in FIG. 5A using the canned internal pressure inspection apparatus according to the present invention, and a pair of pressing rollers of the first measuring means sandwich the can body. The position where the pressure roller is pressed with a pair of the second measuring means sandwiched by the can body, that is, the measurement result when measured 10 times each when the measurement position is indicated by an angle and changed by 10 degrees. It is shown.

As is apparent from the figure, the relative angle difference between the first measuring means 10 and the second measuring means 50 in the diameter direction (or radial direction) is about 60 degrees, and the variation is about 1 as compared with FIG. / 2, which shows that the measurement accuracy is considerably improved.
In addition, when the relative angle difference is about 70 degrees, the variation is significantly reduced to about 3/7 in the case of FIG. (A). Further, when the relative angle difference is around 90 degrees, the variation is minimum, and the variation of the measurement result is It becomes about 1/10 of the case of FIG. (A), and it can be seen that the measurement accuracy is greatly improved.
Considering the above results, the relative angle difference between the first measuring means 10 and the second measuring means 50 is preferably about 90 ± 30 degrees, and more preferably about 90 ± 20 degrees.

Next, a 250 g tin squeezed iron can is filled with a predetermined amount of water, and the amount of liquid nitrogen added to the can is changed little by little before sealing with the can lid, so that the internal pressure of the can is 0.65 kg / cm. ^{2, 1.25Kg / cm 2, 1.85Kg} / cm 2, to produce a canned 2.5 Kg / cm ^2.

FIG. 4 shows the results of measuring the internal pressure of these cans using the internal pressure inspection apparatus for cans according to the present invention (measurement positions changed by 90 degrees between the first measurement means and the second measurement means).
Here, the measured value is determined by the method of the present invention described above, and the internal pressure is determined by an internal pressure gauge after breaking the can. Further, in the figure, the average (X) and standard deviation (σ) of each measured value is obtained, and X ± σ is illustrated.

  Further, in FIG. 5, the internal pressure measurement of the cans having the above-mentioned four types of internal pressures manufactured in the same manner was performed 10 times each with a conventional apparatus (measured the body of the can by the first measuring means) (the measurement position is The results are shown (random for each time) (display is the same as in FIG. 4).

Comparing both figures, even in the conventional apparatus, when the internal pressure is low (1 Kg / cm ² or less), the variation in the internal pressure measurement result is relatively small (however, the variation of the present embodiment is about twice as large. However, it can be seen that the variation becomes extremely large as the internal pressure increases. On the other hand, in the apparatus according to the present embodiment, it can be seen that high measurement accuracy is maintained and variation is small regardless of the internal pressure level.

From these, it is considered that can barrel deformation is likely to occur when the canning pressure is high, and that if the canning pressure is high, a large measurement error is likely to occur even if the difference between the major axis and minor axis of the can is small. . As a result, the present invention has a higher measurement accuracy than conventional devices regardless of the internal pressure of the canned internal pressure, and the present invention is particularly effective when a canned product having an internal pressure of 1 kg / cm ² or more is to be inspected. It is understood that it is effective.

It is a partially broken front view of the 1st measurement means of the internal pressure inspection apparatus of the canned goods concerning one Embodiment of this invention. FIG. 2 is a schematic top view of the apparatus shown in FIG. 1. It is explanatory drawing which shows the relationship between the angle difference of the measurement radial direction in the 1st measurement means of the internal pressure test | inspection apparatus of the can according to this invention, and a 2nd measurement means, and a measurement precision. It is explanatory drawing of the measurement result of the various internal pressure canning by the internal pressure inspection apparatus of the can according to this invention. It is explanatory drawing of the measurement result of various internal pressure canned by the apparatus which has only one conventional measuring means.

Explanation of symbols

10 First measuring means 12 Canned object 14 Roller 50 Second measuring means 54 Roller

Claims (1)

In an internal pressure inspection device for beverage cans having a barrel wall that can be elastically deformed and having a can lid fixed to a beverage can with a thin can barrel,
A conveyor for placing and transporting canned goods to be inspected;
A pair of rollers that are arranged on both sides of the conveyor so as to face each other at a distance narrower than the diameter of the can, sandwiching the can body that is being transported from both sides, and pressing the can body inward in the diameter direction; A first measuring means and a second measuring means, each of which is composed of a detection unit that measures the reaction force of the pressed can, and is arranged at predetermined intervals along the moving direction of the conveyor,
A drive unit for rotating the pair of rollers of the first measuring means at different peripheral speeds, and rotating the can;
The relative angle difference between the first measuring means and the second measuring means in the radial direction is 90 degrees ± 30 degrees due to the difference in rotational speed of the other roller with respect to one roller of the first measuring means. An internal pressure inspection device for canned foods.

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