JP4072455B2 - Leakage inspection method and apparatus for package seal part - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for performing an air leak test on a sealed part of a package body in which a food product or the like is sealed, using a pressure resistant chamber.
[0002]
[Problems to be solved by the invention]
After forcibly aspirating the air inside the packaging bag filled with the package, the sealed package with heat-sealing the opening edge of the packaging bag is subject to decay if there is even a slight air leak. , as shown in JP 59 -133,445 discloses a sealed sealed package again, is carried out leakage test in vacuo the same chamber accommodates a pressure-resistant chamber. For example, even if the apparent value inside the vacuum package has reached the vacuum value, the package bag cannot be completely vacuumed due to oxygen or moisture contained in the package, so if there is a pinhole in the already sealed part The pressure in the pressure-resistant chamber changes due to air leakage, and the leakage of the package can be detected by measuring this change in pressure.
[0003]
The above inspection method will be explained with reference to FIG. 11. The air in the pressure-resistant chamber is sucked, and if the pressure value a of the chamber reaches the complete vacuum value (0 Mpa), the time t is estimated. If an error of the ultimate pressure value b occurs after measurement, it can be detected that there is a delay in the pressure drop like the phantom line c due to air leakage from the package.
[0004]
However, the error b is not always measurable as shown in the figure depending on the size of the pinhole, and the reduced pressure value a of the chamber is not completely measured at the set time t depending on the ambient temperature or the moisture ratio of the air. Since it does not always reach near vacuum (0 Mpa), there is a problem that such measurement is somewhat incomplete.
[0005]
[Solution]
In particular, the present invention provides a method for increasing the detection effect of extremely small pinholes, a step of arranging a wrapping bag in which a bag mouth is not sealed in an airtight pressure resistant chamber, and the pressure resistant chamber in which the wrapping bag is disposed. a step of sucking the air of the inner, when the vacuum value of the breakdown voltage in the chamber reaches a certain value, the pressed between the bag mouth by the sealing material provided in said pressure-resistant chamber, was placed in the sealing material filaments in the step of welding the bag mouth by applying an impulse current, after stopping the air suction of the, at the same time releasing the bag mouth from nipping by the sealing material, the pressure change in the pressure-resistant chamber by the pressure sensor And a measuring step .
[0006]
In the above-described method, while the already sealed portion of the sachet with the bag mouth sealed in the pressure resistant chamber is clamped with a sealing material to prevent air leakage from the pinhole, the air in the pressure resistant chamber is forcibly sucked, Thereafter, the air suction is stopped to stop the flow of air in the pressure-resistant chamber, and the sealing material is opened in such a state. If there is a pinhole at the already-sealed portion of the bag mouth , the sealing material is opened. At the same time, air leaks instantaneously, and the pressure change in the pressure chamber stands out, so it is possible to detect abnormalities even with air leaks from small pinholes.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, a pressure-resistant chamber 13 is constituted by a surface plate 10 on a casing and a lid member 12 supported on the surface plate through a pin 11 so as to be opened and closed. The surface plate 10 is filled with an object to be packaged. The sealing base 15 that supports the bag mouth of the wrapping bag 14 and the lid member 12 are each provided with a sealing member 17 that is operated by a diaphragm actuator 16, and one end of the lid member 12 is flexible. The other end of the tube 18 is connected to a vacuum pump 20 via an electromagnetic three-position direction control valve 19 to form a vacuum line 21.
[0008]
In operation, first, when the lid 11 is brought into contact with the surface plate 10 with the pin 11 as an axis, the switch 22 is closed, the control valve 19 is switched to the first position 19a, and the vacuum bump 20 is an airtight pressure-resistant chamber. As a result of starting the air suction in 13, the vacuum value in the pressure-resistant chamber 13 changes as shown by a curve line A in FIG. 2. In this case, the preliminarily sealed vacuum package 14 tries to expand due to a pressure difference between the inside and outside (residual air inside), but the holding plate 23 provided in the lid member allows unlimited expansion of the vacuum package 14. On the other hand, the sequencer switches the on-off valve 25 while measuring the vacuum value in the pressure-resistant chamber, sucks the air in the lower chamber of the diaphragm 26 with the vacuum pump 20 and pushes the sealing material 17 toward the sealing base 15. Then, the already sealed part of the vacuum package 14 is clamped.
[0009]
Note that in the case of an open wrapping bag 14 in which the bag mouth is not sealed, it is expected that the vacuum value in the pressure-resistant chamber 13 will reach a constant value, and the electric heating filament 24 arranged on the lower surface of the sealing material 17 is applied with an impulse current. The bag mouth is welded by instantaneous heating, and then the already-sealed portion of the vacuum package 14 is clamped and held by the sealing material 17.
[0010]
When the vacuum suction curve A in FIG. 2 reaches the reach limit or reaches the set time t, the sequencer switches the control valve 19 in FIG. 1 to the center position 19b to keep the pressure-resistant chamber 13 in a sealed state, while the on-off valve 25 is switched to the open position, and the clamping action of the sealing material 17 on the package 14 is relaxed. As a result, if there is a pinhole in the already-sealed portion of the vacuum package 14, air in the package 14 instantaneously leaks from the pinhole, and the pressure in the chamber 13 changes rapidly as shown in FIG. However, an alarm signal is transmitted to the controller 31 from the pressure sensor 30 that senses the pressure change B, and then the atmosphere can be reduced to the chamber 13 by selecting the position 19c of the control valve.
[0011]
The sensor 30 may be a sensor for fluorescence analysis in addition to the sensor that measures the pressure change as described above, that is, the sensor reacts air molecules or gas molecules with fluorescence to obtain a residual gas concentration. It can be applied to the detection of gas generated from the package.
[0012]
The following description is an embodiment in which the present invention is applied to an efficient rotary inspection device. That is, FIG. 3 shows that an endless chain 37 is stretched around two large and small gears 35, 36 arranged in two axes, and a large number of surface plates 38 are attached to the chain 37 at equal intervals. The gear 40 fixed to the shaft 39 and the pinion 41 fixed to the motor shaft are connected by a power transmission band 42, and each surface plate 38 is conveyed along an endless track. On the other hand, the belt conveyor 44 installed in the upper region of the rotating track of each surface plate 38 is carried onto the surface plate 38 by controlling the interval between the respective wrapping bags 76.
[0013]
The rotary valve 45 installed at the center of the large gear 35 connects each of the eight lid members 46, which are components of a pressure-resistant chamber that rotates in a circular orbit, to a vacuum source via a hose 47 for air circulation. FIG. 4 is an enlarged view of a partial cross section of the portion.
[0014]
That is, there is a table-type machine base 48 as a base, and a donut-type stationary platen 51 which is a lower component of the rotary valve is placed around the mandrel 49 erected on the machine base 48. On the other hand, a donut-shaped movable platen 52 is slidably disposed on the fixed platen 51. Further, the large gear 35 and the cylindrical guide 54 described above are fixed to the spacer 53 integral with the movable plate 52 with bolts 55. When the large gear 35 is rotated around the mandrel 49 by the power of the chain 37, the movable plate 52, the spacer 53, and the guide 54 are integrally accompanied with the rotation. Each lid member 46 is suspended and supported at the tip of a suspension rod 57 that engages with the lifting rod 56, and a pulley 58 provided at the base end of each suspension rod 57 is formed in the vertical direction of the outer surface of the guide 54. Engage with the slit 59.
[0015]
When the large gear 35 rotates, the roller 60 provided at the lower end of the lifting / lowering rod 56 rolls on the ring-shaped rail 61 concentric with the mandrel 49 and ascends with an upward slope on the upper surface of the rail 61 to bring the pulley 58 into the stopper 62. As a result of the collision, the lid member 46 is separated from the surface plate 38. In contrast, the lid member 46 covers the surface plate 38 in an airtight manner and isolates the package body as the elevating bar 56 is lowered.
[0016]
FIG. 5 shows a sliding surface of the lower fixed platen 51 of the rotary valve, and the two holes 64 and 65 opened in the surface are connected to separate vacuum lines. On the other hand, the imaginary line port 66a shows an opening of a line connected to the lid member 46 via the hose 47 in the movable platen 52 in FIG. 4 and only moves while engaging in the two front and rear holes 64, 65 while moving in the direction of the arrow. The vacuum is applied to the inside of the lid 46 , that is, in the pressure resistant chamber, in two stages, front and rear. Such vacuum two-stage operation is for the purpose of moving each pressure-resistant chamber at high speed.
[0017]
FIG. 6 shows a cross section of the pressure-resistant chamber, and the operation performed by the rotary valve will be described with electromagnetic switching valves 70 and 71 shown individually. In this case, the switching valve 70 installed in the vacuum circuit has a structure that performs the same function as the control valve 19 of FIG.
[0018]
First, by moving the chain 37 with the rotation of the gear 36, the pressure-resistant chamber connected to the chain moves, and when reaching the region where the surface plate 38 and the lid member 46 are in close contact with each other, the first switching valve 70 is passed through, The vacuum pump 72 lowers the vacuum value in the chamber to a set value. In this case, the sensor 79 continuously measures the pressure change value, and then the pressure of the lower chamber 74 of the diaphragm 73 is lowered by the operation of the second switching valve 71, and the sealed portion of the package 76 is sandwiched by the sealing material 75. Press. That is, the small port 66b of the phantom line port 66a in FIG. 5 is a hole for pressure control of the diaphragm lower chamber 74 in FIG. 6, and the port 66b is connected to the groove 77 in FIG. The sealing material 75 is welded by sandwiching the opening of the bag 76 and applying an impulse current to the filament 80. Then, the port 66b is connected to the hole 78 that goes out to the atmosphere, so that the squeezing pressure of the wrapping bag by the sealing material 75 in FIG. 6 is loosened, and the instantaneous sensor 79 measures the pressure inside the lid material 46, and the sealing material 75 is removed. The change value with the pressure value immediately before opening is detected.
[0019]
If there is a pinhole in the sealed part of the bag, the air in the bag escapes in the direction of the pressure-resistant chamber due to the differential pressure, and the pressure of the chamber is changed rapidly. For this reason, the sensor 79 sequentially detects a pinhole from each package transported at equal intervals, and the lids 46 are sequentially separated from the surface plate 38 by opening the virtual line port 66a to the air suction hole 80. It is. In addition, the defective product that is caught by the sensor 79 becomes an alarm target and is mechanically excluded from the line.
[0020]
In FIG. 6, in the case where the bag mouth of the packaging bag 76 arranged on the pressure-resistant chamber is already sealed, that is, in the case of a sealed package, the sealing material 75 is already sealed on the package 76 before air suction of the pressure-resistant chamber. It is desirable to pinch the part. Therefore, the structure of the rotary valve in this case forms the groove 77 in FIG. 5 at the position of the virtual line 77a.
[0021]
The following description is an embodiment in which the present invention is applied to a separate vertical rotary inspection apparatus. The apparatus shown in FIG. 7 includes a rotary bag filling machine 81 and basically a rotary vacuum packing machine 82. More specifically, the structure of the bag filling machine 81 is shown in FIG. Is shown in FIG.
[0022]
That is, in FIG. 8, the rotor 85 is provided with a large number of arms 84, two at the periphery, and the clamper 85 at the tip of each arm intermittently moves in the arrow direction 86 together with the rotor 85. When one set of clampers 85 stops in a section opposite to the loading box 87, the packaging bag 88 is mechanically supplied to these clampers 85. While the rotor 85 makes one rotation, the opening of the wrapping bag 88 is opened to fill the inside of the package, and then the open package is released along the arrow 89 in the final section. In other words, in FIG. 7, a means for carrying the package from the bagging machine 81 one after another into the pressure chamber 83 of the vacuum packaging machine 82 is provided.
[0023]
In the vacuum packaging machine in FIG. 7, ten pressure chambers 83 are arranged at equal intervals on the periphery of the disk 91, and the rotary valve 92 at the center and each pressure chamber 83 are connected via a flexible hose 93. In this configuration, a partial cross-section is shown in an enlarged view in FIG.
[0024]
That is, the cylindrical main shaft 97 of the disk 91 described above is supported by the bearing 96 installed on the table type machine base 95, and the main body 99 which is a component of the pressure-resistant chamber is mounted on the bracket 98 fixed to the disk 91. The lid member 101 is supported on the bracket via the pin 100. By rotating the gear 102 fixed to the lower end of the main shaft 97 by the input from the driving shaft 103, the disk 91 continuously moves each pressure-resistant chamber 83 along the circular path.
[0025]
Further, the lower end of the same vacuum suction tube 104 disposed in the hollow portion of the cylindrical main shaft 97 is fixed to the machine base 95 via the connector 105, while the fixed plate 106 is fixed to the upper end of the vacuum suction tube 104. The rotary valve 92 described above comprising the movable platen 107 is installed, and the valve 92 and each lid member 101 are connected via the hose 93 as described above.
[0026]
As shown in FIG. 10, the main body 99, which is a constituent member of the pressure-resistant chamber, is provided with shaft rods 107 that are rotatable on both sides of the inside, and these shaft rods 107 are each provided with clamping claws 108 at the upper ends thereof. The support nail 108 is pressed against the support seat 120 protruding from the main body wall by the operation of the lever 109 to support the package body 121. The support of the package body 121 by the nail claw 108 is the main body 99 that rotates and moves in FIG. The lever 109 is subjected to the resistance of the annular cam 122.
[0027]
The lid 101 in FIG. 9 is provided with a diaphragm actuator 125 for operating the sealing material 124. The configuration of the rotary valve 92 in FIG. 9 is the same as that shown in FIG. 5, and as already described in FIG. The sealed portion of the package 121 suspended by the clamping claws 108 in the sealed pressure-resistant chamber 83 is clamped with a sealing material, and air suction of the pressure-resistant chamber is stopped by the rotary valve 92. The pressure in the pressure-resistant chamber is measured by a sensor with the pinching pressure relaxed, and a package with pinholes is efficiently detected.
[0028]
The pressure control of each pressure-resistant chamber shown in FIG. 3 and FIG. 9 and the control of each timing of clamping and releasing of the already-sealed portion of the sealed package with a sealing material are performed by a rotary valve that rotates integrally with each pressure-resistant chamber. As described above, the electromagnetic control valves 19 and 25 shown in FIG. 1 can be installed in each pressure-resistant chamber, and the switching timing of these control valves can be controlled by a controller.
[0029]
The target package to be subjected to the pinhole inspection may be a vacuum package or an air-packed package. Therefore, the pressure drop value of the pressure-resistant chamber when releasing the clamping pressure of the already-sealed part by the sealing material. Is not necessarily near full vacuum (0 Mpa). Whether or not the sealing material has an impulse filament for heating is determined depending on whether or not a seal has already been applied as described in the package to be inspected.
[Brief description of the drawings]
FIG. 1 is a side view of a partial cross section of a leak inspection apparatus. FIG. 2 is an explanatory diagram of the inspection principle. FIG. 3 is a plan view of a rotary inspection apparatus. FIG. 4 is a partial cross section of the previous figure. FIG. 6 is a sectional view of a pressure-resistant chamber. FIG. 7 is a plan view of a rotary inspection device. FIG. 8 is a perspective view of a bagging and packaging machine. FIG. 9 is a partial sectional view of a rotary inspection device. ] Front view of pressure-resistant chamber [Fig. 11] Illustration of conventional configuration [Explanation of symbols]
10, 38 ... Surface plate 12, 46, 101 ... Cover material 13, 83 ... Pressure-resistant chambers 14, 76, 88, 121 ... Packaging (packaging)
17, 75, 124 ... Sealing material 18, 47, 93 ... Flexible hose (vacuum line)
19, 25, 70, 71 ... Electromagnetic switching valve 24, 80 ... Heating filament 30, 79 ... Sensor 31 ... Controller 35, 36 ... Gear 37 ... Endless chain 51, 92 ... Rotary valve 52 ... Fixed plate 53 ... Movable plates 64, 65 ... vacuum port 81 ... bagging and packaging machine 82 ... vacuum device 85 ... clamper 99 ... main body 108 ... clamping jaws

Claims (6)

A step of placing a wrapping bag in which the bag mouth is not sealed in an airtight pressure-resistant chamber ;
A step of sucking air in the pressure-resistant chamber in which the sachet is disposed ;
When the vacuum value of the breakdown voltage in the chamber reaches a certain value, the pressed between the bag mouth by the sealing material provided in said pressure-resistant chamber, said bag by applying an impulse current to a filament installed in the sealing material a step of welding the mouth,
An inspection method comprising a step of measuring the pressure change in the pressure-resistant chamber by a pressure sensor at the same time as releasing the bag mouth from the pinching pressure by the sealing material after stopping the air suction. A pressure-resistant chamber that is openable and closable, in which an unsealed bag is placed inside ;
A sealing material for clamping the bag mouth in the closed pressure-resistant chamber ;
A vacuum line for forcibly sucking air in the pressure-resistant chamber;
A sensor for measuring the pressure in the pressure-resistant chamber;
Comprising means for issuing an alarm according to the pressure change value detected by the sensor,
When the wrapping bag is disposed in the pressure-resistant chamber, air in the pressure-resistant chamber is sucked by the vacuum line, and when the vacuum value in the pressure-resistant chamber reaches a certain value, the wrapping bag is sealed. After sealing with a seal material, it is welded by applying an impulse current to the filament arranged in the seal material, and then the vacuum line is closed to stop air suction. A device that releases pressure in the bag mouth and simultaneously measures the pressure in the pressure-resistant chamber by the sensor and issues an alarm according to the detected pressure change value . A large number of surface plates which are arranged inside a bag with an unsealed bag mouth and move along an endless track,
A lid member that airtightly covers each moving platen in a specified region of the circular orbit in the endless orbit ,
A sealing material for clamping the bag mouth in a pressure-resistant chamber formed by the surface plate and the lid material;
A valve mechanism connected to a vacuum line for sequentially lowering the pressure in the pressure-resistant chamber;
A sensor for measuring the pressure in the pressure-resistant chamber;
Comprising means for issuing an alarm according to the pressure change value detected by the sensor,
When the lid member is airtightly covered on the surface plate on which the wrapping bag is disposed, the air in the pressure-resistant chamber is sucked by the vacuum line, and when the vacuum value in the pressure-resistant chamber reaches a certain value, After sealing the unsealed bag mouth in the sachet with the sealing material and applying an impulse to the filament installed in the sealing material, and then closing the vacuum line and stopping air suction , A device that releases the bag mouth from the clamping pressure by the sealing material, and simultaneously measures the pressure in the pressure-resistant chamber by the sensor and issues an alarm according to the detected pressure change value. A bagging and packaging machine that has a plurality of clampers, transports the packaging bags suspended by the respective clampers along an endless track, and sequentially fills the packages in the respective packaging bags during transportation;
Both the adjacent to the bag-filling packaging machine, and carrying a number of openable-voltage chamber at regular intervals along the endless track, the pressure of each of the pressure-resistant chamber to close during transport and placed in a vacuum line valve Rotary vacuum equipment that is allowed to descend sequentially with the mechanism ,
Means for sequentially transferring the sachets formed by the bagging and packaging machine to the clamping claws of each pressure-resistant chamber;
A sealing material for clamping the bag mouth of the bag supported by the clamping claws in the pressure-resistant chamber;
A sensor for measuring the pressure in the pressure-resistant chamber ;
Comprising means for issuing an alarm according to the pressure change value detected by the sensor,
When the bag formed by the bag packing machine is isolated in the pressure chamber, the vacuum line sucks air in the pressure chamber, and the vacuum value in the pressure chamber reaches a certain value. Sometimes, the bag mouth of the wrapping bag is clamped with the sealing material, and impulse current is applied to the filament provided in the sealing material for welding, and then the bag mouth is released from the clamping pressure by the sealing material. to the same time, it performs a pressure measurement inside the pressure chamber by the sensor, device for issuing an alarm in response to the detected pressure change value. A rotary valve that rotates integrally with the pressure-resistant chamber controls the pressure drop inside the pressure-resistant chamber, the pressure of the bag mouth of the bag by the sealing material, and the timing of releasing the bag mouth from the pressure by the sealing material. The apparatus according to claim 3 or 4, which is performed. An electromagnetic switching valve that rotates integrally with the pressure-resistant chamber to control the pressure drop inside the pressure-resistant chamber, the pressure of the bag mouth of the bag by the sealing material, and the timing of releasing the bag mouth from the pressure by the sealing material The apparatus of Claim 3 or 4 performed by these.

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