JPS6346843Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrode used for discharge-type pinhole detection in a sealed package.

More specifically, the present invention involves placing a hermetically sealed package made of an electrically insulating material such as plastic or glass for an infusion or retort food, etc. between electrodes, and applying a voltage between the electrodes to seal the package. The present invention relates to an electrode device used for generating a discharge current on a package and detecting the discharge current to inspect the presence or absence of pinholes, cracks, etc. in the sealed package.

In addition, in the claims section of the Utility Model Answer and the following description, the above-mentioned pinholes, cracks, etc. are collectively referred to as "pinholes."

The electrode of the electrode device conventionally used in such a pinhole presence inspection is fixed at the inspection position in the transfer path of the sealed package C so as to face the transfer path, as shown in FIG. 1, for example. Electrode E ₁ ,
It was _E2 .

Therefore, when the parts to be inspected of the sealed package C are parts C ₁ and C ₂ and a part C ₃ which is recessed relative to these parts as shown in the figure, the distance between the electrode E ₁ and the part to be tested is is the distance l ₁ for the parts C ₁ and C ₂ , and the distance l ₂ for the part C ₃ , l ₂ >l ₁ .

In this way, the distance between the electrode and the tested part changes depending on the uneven shape of the tested part, so the electrode E ₁
If the voltage applied between C and E ₂ is constant, the pinhole at site C ₃ may not be detected due to insufficient voltage because the distance l ₂ is too long. If the applied voltage is set high in order to detect even the pinhole in the portion _C3 , a situation may occur in which the walls of the package in the portions _C1 and _C2 become thin against the high voltage, causing dielectric breakdown. In addition, the part to be inspected of the above-mentioned sealed package
Even if there is no unevenness between C ₁ , C ₂ , and C ₃ and the distance between the electrode and the area to be inspected is kept constant, if there is a difference in wall thickness between these areas, , the same problem occurs when there is unevenness.

In other words, if the applied voltage is constant, pinholes cannot be detected in areas with thick walls due to insufficient voltage, and if the applied voltage is set high, dielectric breakdown occurs in areas with thin walls. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode device for use in a discharge-type pinhole inspection of a sealed package that solves the above-mentioned problems.

The object of the present invention is to provide an electrode device for use in the discharge-type pinhole presence inspection of a sealed package, which includes an electrode facing the transfer path at an inspection position in the transfer path of the sealed package, and an electrode along the transfer path. When the incoming sealed package passes through the inspection position, the electrode is moved to the inspected area so that the distance between the electrode and the inspected part of the sealed package is maintained at a discharge distance that allows pinhole detection. an electrode driving device for moving the electrode back and forth with respect to the region, a spring device in which the electrode driving device applies a biasing force to the electrode in a forward direction or a backward direction, and an opposite biasing force to the electrode that exceeds the biasing force by the spring device. An electromagnetic device that can give power,
This is achieved by an electrode device comprising a switch device that turns on and off the electromagnetic device depending on the condition (unevenness condition and/or wall thickness condition) of the inspected portion of the sealed package. .

The embodiments of the present invention will be explained below based on drawings, taking as an example the case used to inspect the presence of pinholes in polyethylene sealed packaging bodies (hereinafter simply referred to as "packaging bodies") in which infusions for injection are sealed. do.

FIG. 2 schematically shows an example of a so-called differential pinhole presence/absence inspection device.

This differential type device includes a first electrode 10 which is provided on the transfer path and can face the package A at an inspection position in the transfer path of the package A sent by a feeding device (not shown); Two second electrodes 21 and 22 are provided. The second electrodes 21 and 22 are components of the electrode device 20 which is an embodiment of the present invention.

Each second electrode is positioned approximately equidistant from electrode 10. One second electrode 21 is connected to one terminal of a first impedance 41, and the other second electrode 22 is connected to one terminal of a second impedance 42 arranged in parallel with the first impedance. 1st
Between the electrode 10 and the other terminal of the impedances 41 and 42, the secondary side of a step-up transformer 54 (described later) of the AC power supply section 5 is connected. Further, the other terminals of the impedances 41 and 42 are grounded for safety. The power supply unit 5 includes an AC power supply 51 and an oscillator 52 that generates a desired alternating waveform based on the output of the AC power supply 51.
(the frequency of the power supply output can also be changed), an amplifier 53 that amplifies the oscillator output, and a step-up transformer 54 that generates a desired high voltage on the secondary side based on the amplifier output.
and are equipped with any low voltage,
A desired high voltage and a desired high frequency can be obtained on the secondary side of the transformer 54 from any low frequency.
Reference numeral 6 denotes a determiner for individually detecting the discharge current generated on the package A from two systems to determine the presence or absence of a pinhole. The current flowing between each impedance is individually detected and the difference is converted into a voltage difference between both ends of each impedance. To explain further, this determiner 6 includes a differential amplifier 61 connected to the electrodes 21 and 22, a waveform conversion circuit 62 that extracts only a waveform equal to or higher than a certain set value from the output of the amplifier 61, and an output wave of the circuit 62. It includes an absolute value circuit 63 for aligning in the positive or negative direction, and a comparator (voltage level determiner) 64 connected to the circuit.

Thus, when a voltage is applied between the electrode 10 and the electrodes 21, 22, two systems of corona discharge current are generated on the package A if there are no pinholes in the package. This current difference will be substantially zero or close to zero.

If there is a pinhole in package A, one of the two discharge currents will be a spark discharge current, so
The difference between the two system discharge currents becomes large.

Therefore, since the determiner 6 detects the discharge currents of the two systems individually and converts the difference into voltage, it can be determined that there is no pinhole when the converted value is zero or close to zero, and that there is a pinhole when it is large. , or when the converted value is smaller than a predetermined value, it can be determined that there is no pinhole, and when it is larger, it can be determined that there is a pinhole.

FIG. 3 schematically shows an example of a so-called single-action pinhole inspection device.

In this device example, the second electrodes 21 and 22 are both connected to one terminal of one impedance 4, and the first electrode 10 is connected to the other terminal of the impedance 4 via the power supply section 5'. Furthermore, a determiner 60 is connected to the impedance 4. A terminal of the power supply section 5' is grounded.

Thus, when a voltage is applied between the electrode 10 and the electrodes 21, 22, if there is no pinhole in the package A, a corona discharge current _i1 is generated between the electrodes,
If there is a pinhole, a spark discharge current i ₂ will occur between the electrodes. Since there is a relationship of i ₂ > i ₁ , i ₂ >
A value (certain reference value) i _s that satisfies i _s > i ₁ is set, and the discharge current generated between the electrodes is detected according to each package A, and the detected current is determined from i _s. If it is large, it is determined that there is a pinhole, and if it is smaller than i _s , it is determined that there is no pinhole.

Regarding the pinhole presence inspection method and device for the differential type and single acting type mentioned above, it has already been published in Japanese Patent Application Laid-Open No. 54-76284.
Since it is described in the publication, no further explanation will be given here.

The electrode device 20 of the present invention used in such a pinhole presence inspection will be described in further detail.
Each electrode 21, 22 of this device 20 extends slidably through the front portion 231 of the base body 23 into the base body;
It is held by the electrode holding part 24. A movable rod 25 is connected to an electromagnet device 25 fixed to the rear surface of the base body 23.
1 extends into the base body 23 , which is connected to the holding part 24 . A coil spring 26 is fitted to each electrode 21, 22 between the base body front part 231 and the holding part 24. This coil spring applies a force that biases the electrodes 21 and 22 in the direction of retreating from the package A, and places the electrodes 21 and 22 in the retreated position when the electromagnetic device 25 is in the OFF state. Electromagnet device 25
is the movable rod 25 in the energized (on) state.
1 can be made to protrude, and the electrodes 21 and 22 can be moved to their advanced positions against the elasticity of the coil spring 26.

This electromagnetic device 25 is turned on and off by a switch device depending on the unevenness of the inspected portion of the package A passing through the inspection position. This switch device includes a known circuit (not shown) for energizing the electromagnet device 25 and includes a switch portion, and a timing device 27 for operating the switch portion.
It is equipped with The _timing device 27, as shown in _FIG .
It includes a disk 271 that rotates once while A ₃ (see FIG. 5) passes the inspection position, and a photomicro sensor 272 that faces the disk 271. Disk 271
has a notch 273 having a size corresponding to the time that the part to be inspected A ₃ , which is a recess with respect to the parts to be inspected A ₁ and A ₂ , passes through the inspection position, and this notch is used for the photomicroscope. It is detected by a sensor 272, and the switch section is closed in response to this detection signal. When the switch section is closed, the electromagnetic device 25 is turned on, and the electrodes 21, 2
2 is projected from its retracted position to its forward position.

Therefore, as can be seen from FIG. 5 (electrode 21 is located below electrode 22 and is not shown in the figure), electrodes 21 and 22 are located at portions A ₁ and A ₂ of package A.
When passing through the inspection position, it is in the backward position and maintains an appropriate discharge distance L ₁ from parts A ₁ and A ₂ that can detect pinholes, and when part A ₃ passes through the inspection position, it is in the forward position. Keep a discharge distance L ₂ between the part A ₃ and the pinhole detectable distance. L ₁ > L ₂
This is because the wall of the package is thicker in the region A ₃ than in the regions A ₁ and A ₂ due to the formation of the hanging portion A ₄ .

In this way, while the applied voltage remains constant, the parts A ₁ , A ₂ ,
_A3 pinhole inspection can be performed safely and accurately.

Next, another embodiment 30 of the present invention shown in FIGS. 6 and 7 will be described.

In this electrode device 30, blocks 31,
A frame is constructed by arranging blocks 32 facing each other vertically with a gap between them, and connecting the back surfaces of the blocks with a plate 33, and the frame is arranged with the side opposite to the plate 33 facing the transport path of the package A. The gap between the blocks 31 and 32 is continuous with the introduction guide gap 301 in which the vertical interval becomes gradually narrower so as to guide the introduction of the hanging part _A4 in the inspection area of the package A between the blocks. Electrode placement gap 30
2, and a feed guide gap 303 following the gap 302.
It consists of.

In the gap 302, two electrodes 341 and 342 corresponding to the electrodes 21 and 22 shown in FIG.
1, 32, a vertical shaft 351 rotatably supported;
352 is cantilevered by the end located within the gap 302. Spring support arms 361, 362 are attached to the other ends of the vertical shafts 351, 352, and the blocks 31, 32 and the arms 3
Tension springs 371 and 372 are tensioned between 61 and 362. This spring provides a biasing force via the shafts 351, 352 that causes the electrodes 341, 342 to rotate forward toward the package A (see FIG. 7). Further, horizontal arms 381, 382 are cantilevered at the other ends of the vertical shafts 351, 352.

An electromagnetic device 393 is held on the back of the frame composed of the blocks 31, 32 and the connecting plate 33 via a mounting frame 394, and a plate 396 is fixed to a movable rod 395 protruding from the device 393. Push rods 391 and 392 are cantilevered at the upper and lower ends and extend slidably through the frame toward arms 381 and 382.

When the electromagnet device 393 is in the off state, the electrodes 341 and 342 are closed by the action of the springs 371 and 372.
is placed in the forward position (the position shown by the imaginary line in FIG. 7) where the inspection site _A3 , which has become a recess, is to be inspected.

When the electromagnet device 393 is in the ON state, the movable rod 395 is projected, and the arm 3 is connected to the arm 3 via the plate 396 and push rods 391 and 392.
81, 382, and then springs 371, 372
The electrodes 341 and 342 are moved against the elasticity of the test area.
Move A ₁ and A ₂ to the retracted position (indicated by the broken line in Figure 7) to be inspected.

This electromagnetic device 393 is also turned on and off by a switch device (not shown) similar to that in the first embodiment already described, depending on the state of the inspected portion of the package A passing through the inspection position. However, in the embodiments of Figures 6 and 7, the switch section in the circuit for energizing the electromagnet device is normally closed (therefore, the electromagnet is always on), and the timing device is not exposed. The switch section is opened while the inspection site _A3 passes through the inspection position.

The switch device for turning on and off the electromagnetic device in each of the embodiments described above is not limited to the above example, and for example, the timing device may be replaced with a limit switch or a proximity switch.

As described above, according to the present invention, the distance between the electrode and the part to be inspected of the sealed package can be maintained at a discharge distance that allows pinhole detection, regardless of the shape of the part to be inspected or the difference in wall thickness. The applied voltage can also be set to the minimum necessary constant value, and there is an advantage that pinhole presence inspection can be performed accurately regardless of the shape or wall thickness difference of the part to be inspected, and without fear of causing dielectric breakdown of the part.

Note that the electrode 10 in the pinhole inspection device shown in FIGS. 2 and 3 has a peripheral portion shaped in accordance with the contour of the other inspected area A' of the package A, and It is a rotating electrode that rotates as the body A is sequentially transferred, so that its front part can face the area to be inspected A'.

This electrode can be constructed, for example, by stacking a plurality of plate-shaped electrode elements, each of which has a portion of each of the aforesaid portions, in the direction of the electrode rotation axis.

An example of this rotating electrode is shown in FIG.
This electrode 1 has a plurality of prongs 11 in its peripheral part 12, each having a shape that roughly follows the contour of the mouth A' (tested part) of the package A with which it should come into contact or approach, and has an arm 13. It is rotatably supported by a shaft 14. The arm 13 is further rotatably supported by a fixed frame 15, and is constantly biased by an appropriate spring means (not shown) so as to position the electrode at an inspection position in the travel path of the package A. There is. Further, this electrode is formed to be slightly wider and smoother in the vicinity of the entrance 110 of the contacting or approaching portion 11 so that the electrode can smoothly start contacting or approaching the package A, which will be described later.

The electrode includes a plurality of plate-shaped electrode elements 16
a, 16b, 16c, . With this configuration, each element can be easily obtained by press working and all that is required is to stack these elements, making it easy to form a part that matches the outline of a predetermined part of the object that the electrode is to contact. There are advantages that can be obtained.

The plurality of packages A, which are sequentially transferred by a feeding device (not shown), have their mouths A' start contacting or approaching the proximal part 11 of the electrode, and at the same time, the electrodes are slightly lifted against the spring means. Start rotating the electrode.

Due to the movement of the package A and the accompanying rotation of the electrode, the package mouth A' is sufficiently and reliably connected to the front part 11.
If there is a pinhole in the opening A', a discharge current sufficient to determine that there is a pinhole will be generated, and then the electrode will move away from the electrode. 1
When one package A leaves the electrode, the next part 11 is placed in a position to start contacting the next package A.

The rotating electrode 1 is designed to rotate as the package A moves, but may be driven by an appropriate drive means (not shown) at a speed that is synchronized with the moving speed of the package A, for example. In this case, the part 11 is 1
Sometimes even one is enough.

According to the above-mentioned rotating electrode, the front part of the electrode, which is shaped according to the outline of the area to be inspected, can face the area to be inspected as the electrode rotates in accordance with the transfer of the package A. It is possible to reliably bring the electrode into contact with or approach the inspection site. Therefore, if this rotating electrode is used together with the electrode device of the present invention, it is possible to dramatically improve pinhole detection accuracy and inspection speed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional example of pinhole presence inspection in a sealed package, and Figs. 2 and 3 are examples of differential and single-acting pinhole presence inspection devices using the first implementation electrode device of the present invention. 4 is a perspective view of an example of a timing device, FIG. 5 is an explanatory diagram of a pinhole presence inspection situation using the electrode device shown in FIGS. 2 and 3, and FIGS. 6 and 7 are A front view and a plan view of another embodiment of the present invention, and FIG. 8 is a perspective view showing an example of a rotating electrode. 20, 30... Example of the electrode device of the present invention, 21, 2
2,341,342... Electrode, l ₁ , l ₂ , L ₁ , L ₂ ...
...Distance between electrode and test site, 26,371,3
72... Spring, 25,393... Electromagnetic device,
C, A... Sealed package, C ₁ , C ₂ , C ₃ , A ₁ , A ₂ ,
A ₃ ... Part to be inspected.

Claims (1)

[Scope of utility model registration request] An electrode device used for discharge-type pinhole presence inspection of sealed packages, comprising: an electrode facing the transfer path at an inspection position in the transfer path of the sealed package; and a sealed package sent along the transfer path. When the electrode passes through the inspection position, the electrode is moved back and forth with respect to the inspection area so that the distance between the electrode and the inspection area of the sealed package is maintained at a discharge distance that allows pinhole detection. an electrode driving device, wherein the electrode driving device includes a spring device that applies a biasing force in the forward direction or the backward direction of the electrode, and an electromagnet that can apply a biasing force opposite to the biasing force by the spring device to the electrode. 1. An electrode device comprising: a device; and a switch device that turns on and off the electromagnetic device depending on the state of the inspected portion of the sealed package.