Laser gas concentration measuring device

Abstract

To provide a laser type gas concentration measurement device with which product inspection steps are speeded up and inspection accuracy is improved.SOLUTION: The laser type gas concentration measurement device comprises a conveyance device 11 for conveying a pillow packaging bag B, a laser generation unit 12, and a laser reception unit 13. The conveyance device is configured from a two-gang conveyor 14 composed of a first belt conveyor 16a and a second belt conveyor 16b which are juxtaposed across a space 15, an upstream conveyor 50 which is provided upstream of the two-gang conveyor, and a downstream conveyor 55 which is provided downstream. By assembling the two-gang conveyor composed of these belt conveyors into the middle of a conveyance path, it is made possible to secure an extended measurement time independently of a product inspection step using the measurement device and improve the accuracy of inspection, as well as quickly exchange the pillow packaging bags after measurement and thereby speeding up the production inspection step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser gas concentration measuring device configured to transmit laser light through a packaging bag, a packaging container, or a packaging body similar thereto that is sealed after gas replacement, and measure the gas concentration of a specific gas remaining in the packaging body.

Background Art

[0002] Conventionally, inspection of products in which articles are stored in a packaging bag or a packaging container has generally been sampling inspection in which a predetermined number of samples are extracted from a plurality of manufactured products for inspection. Such sampling inspection can certainly precisely inspect the residual gas concentration of each of the extracted samples, but when viewed as an inspection of all products as a whole, the inspection accuracy is poor, and only the occurrence rate of defective products is obtained statistically.

[0003] Therefore, in recent years, a method of irradiating a product with laser light to inspect the entire quantity of the product has been carried out. The gas concentration measuring method in the packaging machine disclosed in Japanese Patent Application Laid-Open No. 2012-208126 uses a laser gas concentration measuring device including a laser generation unit having a function of irradiating a specific gas with laser light of a specific wavelength by a transmitter, and a laser light that is oscillated from the transmitter and passes through the specific gas is received by a receiver, and measures the intensity of the laser light absorbed by the gas and outputs the concentration of the gas from the intensity. A gas purge chamber of the laser gas concentration measuring device in which a transmitter and a receiver are arranged at a predetermined interval is provided in the product discharge path of the packaging machine that fills a pillow packaging bag with an article, performs gas replacement, and then seals the opening. The concentration of a specific gas in the pillow packaging bag passing between the transmitter and the receiver was measured with a purge gas flowing through the gas purge chamber. As a result, the concentration of the specific gas inside can be quickly measured for all pillow packaging bags without damaging the packaging bags by the laser gas concentration measuring device provided in the packaging machine. In recent years, in this way, a laser-type gas concentration measuring device has been used to nondestructively inspect all of the products formed by a packaging machine, thereby improving the inspection accuracy of the gas concentration of a specific gas remaining in the product.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, first, in the above gas concentration measurement method, a configuration in which a gas purge chamber filled with an inert gas such as nitrogen gas is provided on the product discharge path of the packaging machine and a pillow packaging bag passing through the gas purge chamber is temporarily stopped becomes the first problem. That is, when the packaging machine is speeded up, in a configuration where the inspection unit inspects each of the packaging products continuously carried out from the packaging machine one by one, there is a risk that the packaging products will stay in the inspection unit, so-called bottlenecking.

[0006] Second, a configuration for improving the measurement accuracy of the laser-type gas concentration measuring device becomes a problem. Here, the laser-type gas concentration measuring device is configured to measure the gas concentration based on the absorbance of a specific gas remaining in the packaging bag when laser light is transmitted through the packaging bag, and the specific gas absorbs the laser light. Since the absorbance is based on the ratio of the molecules of the specific gas existing on the optical path between the laser generation unit and the laser light receiving unit that absorb the specific spectrum of the laser light, it is known that the measurement accuracy can be improved by causing the molecules existing on the optical path to absorb more of the specific spectrum. A method for absorbing more of this specific spectrum is to increase the optical path length or increase the irradiation time on the same optical path. However, in the above gas concentration measurement method, in the gas purge chamber provided at a position with limited space on the packaging machine, it is difficult to ensure a long optical path length. Moreover, since the laser generation unit and the laser light receiving unit are fixed at predetermined positions in the gas purge chamber, only the laser light is instantaneously irradiated onto the passing pillow packaging bag, and there is a problem that it is impossible to ensure a long irradiation time on the same optical path.

[0007] Therefore, the problem to be solved by the present invention is to provide a laser-type gas concentration measuring device that speeds up the product inspection process and improves the inspection accuracy.

Means for Solving the Problem

[0008] The laser-type gas concentration measuring device according to claim 1 includes a transport path composed of a conveyor on which a packaging bag or a packaging container that has been gas-replaced and sealed or a packaging body similar thereto is placed, and a transport device that transports the packaging bodies at a predetermined transport speed, A laser-type gas concentration measuring device composed of a laser generation unit that emits laser light of a specific wavelength and a laser light receiving unit that receives the laser light, A double-belt conveyor composed of a first belt conveyor and a second belt conveyor arranged in parallel with a gap of a predetermined width interposed therebetween is provided in the middle of the transport path, A moving path is provided such that the laser generation unit and the laser light receiving unit, which are arranged to face each other in the vertical direction with the gap therebetween, move in parallel with the conveyance path from the start end to the end of the double-belt conveyor at a moving speed synchronized with the conveyance speed. When the packaging bodies being transported on the transport path are placed on the double-belt conveyor, The laser generation unit and the laser light receiving unit moving along the moving path stop relatively with respect to the measurement points provided on the packages. The laser light emitted from the laser generation unit passes through the packaging bodies and the gap and is received by the laser light receiving unit, The gas concentration of a specific gas remaining in the packaging bodies is measured based on the absorption spectrum of the specific wavelength that changes before and after passing through the packaging bodies.

[0009] The laser gas concentration measuring device according to claim 2 is the invention according to claim 1, wherein when the laser generation unit and the laser light receiving unit reach the end of the double belt conveyor, either both or one of the laser generation unit and the laser light receiving unit is provided with a return path for returning from the end to the start along a substantially U-shaped locus along the vertical direction on the anti-gap side.

[0010] The laser gas concentration measuring device according to claim 3 includes a transport path composed of a conveyor on which a packaging bag or a packaging container that has been gas-replaced and sealed or a packaging body similar thereto is placed, and a transport device that transports the packaging bodies at a predetermined transport speed, a laser gas concentration measuring device composed of a laser generation unit that emits laser light of a specific wavelength and a laser light receiving unit that receives the laser light, a double belt conveyor composed of a first belt conveyor and a second belt conveyor arranged in parallel with a gap of a predetermined width in the middle of the transport path is provided, A main reflecting mirror is disposed in the gap. when the packaging bodies being transported on the transport path are placed on the double belt conveyor, the laser light emitted from the laser generation unit passes through the packaging bodies and the gap, After being reflected by the main reflecting mirror and is received by the laser light receiving unit, characterized in that the gas concentration of a specific gas remaining in the packaging bodies is measured based on the absorption spectrum of the specific wavelength that changes before and after passing through the packaging bodies.

[0011] The laser gas concentration measuring device according to claim 4 is the invention according to claim 3, wherein the laser light emitted from the laser generation unit is reflected by the main reflecting mirror and received by the laser light receiving unit while following the same optical path.

[0012] The laser gas concentration measuring device according to claim 5 is claim 3In the invention described in [reference], a sub-reflector that is parallel to and faces the main reflector with the packages therebetween is disposed opposite thereto, characterized in that the laser beam emitted from the laser generation unit is reflected between the main reflector and the sub-reflector and then received by the laser light receiving unit.

Advantages of the Invention

[0015] According to the laser-type gas concentration measuring device of the present invention, a double-belt conveyor including a first belt conveyor and a second belt conveyor arranged in parallel with a predetermined-width gap therebetween is provided in the middle of a conveyance path formed by a conveyor included in a conveyance device. Then, the laser generation unit and the laser light receiving unit are arranged such that the laser beam emitted from the laser generation unit passes through the packages and the gap and is received by the laser light receiving unit, and the gas concentration is measured when the packages are being conveyed on the double-belt conveyor. Preferably, the laser generation unit and the laser light receiving unit are arranged to face each other vertically with the gap therebetween. Here, when the conveyor on the upstream side of the double-belt conveyor is referred to as the upstream conveyor and the conveyor on the downstream side is referred to as the downstream conveyor, when sequentially measuring packages continuously conveyed on the conveyor, if the conveyance speed is increased, the measurement time will be shortened accordingly. However, if the upstream conveyor and the downstream conveyor are separated from each other, and the packages are temporarily stopped on the double-belt conveyor and measured one by one and then replaced with the next package, a predetermined measurement time can be easily ensured even when the conveyance speed is increased. As a result, when measuring the gas concentration, the packages can be sequentially replaced and measured, so that the product inspection process can be speeded up.

[0016] Also preferably, the laser generation unit and the laser light receiving unit are moved at a moving speed synchronized with the packages conveyed from the start end to the end end of the double-belt conveyor. At this time, the gas concentration is measured such that the laser generation unit and the laser light receiving unit relatively stop with respect to a measurement point provided at a predetermined position of the packaging bags. As a result, the irradiation time of the laser beam can be extended, so that the product inspection process can be speeded up and the inspection accuracy can be improved.

[0017] More preferably, a main reflecting mirror is provided in the gap, and the laser beam emitted from the laser generating section is reflected and received by the laser light receiving section, or a sub-reflecting mirror is disposed opposite to the main reflecting mirror in parallel, and the laser beam emitted from the laser generating section is repeatedly reflected between the main and sub-reflecting mirrors and received by the laser light receiving section. As a result, the optical path length of the laser beam can be extended, so that the product inspection process can be speeded up and the inspection accuracy can be improved.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

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Example 1

[0019] An embodiment of a laser gas concentration measuring device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing an outline of the configuration of the laser gas concentration measuring device according to the present embodiment, and FIG. 2 is a side view showing an outline of the configuration of the laser gas concentration measuring device according to the present embodiment.

[0020] As shown in FIGS. 1 and 2, the laser gas concentration measuring device 10 includes a conveying device 11 that conveys packages on a conveying path at a predetermined conveying speed, a laser generation unit 12 that emits laser light of a specific wavelength, and a laser light receiving unit 13 that receives the laser light. The packages are those that can package a packaging bag, a packaging container, or a packaged object similar thereto. In this embodiment, a pillow packaging bag B is exemplified, but it is not limited thereto. For example, in addition to a bag-shaped packaging material, a cup, a tray, etc. may also be used. As shown in FIG. 1, the pillow packaging bag B is a packaging bag formed by sealing the ends of a predetermined film that is rolled up and overlapped to form a cylindrical body, storing the packaged object, and sealing the open end. In this embodiment, as shown in FIG. 1, the pillow packaging bags B are separated one by one and conveyed on the conveying device, but it is not limited thereto, and a continuous packaging pillow packaging bag in which two or more pillow packaging bags B are connected and formed may also be used. The film constituting the pillow packaging bag B is preferably made of a synthetic resin such as vinyl chloride, polyethylene, or polypropylene. Here, if the transmittance of the laser light with respect to the film is 0.00001% or more and less than 100%, even when the pillow packaging bag B is colored, the laser light can pass through, so the laser gas concentration measuring device 10 according to the present embodiment is effective. As shown in FIG. 2, the pillow packaging bag B according to the present embodiment has measurement points P0, P0 through which laser light can pass. Further, even when the pillow packaging bag B is colored and it is difficult for the laser light to pass through, it is sufficient to provide window portions through which the laser light can pass at the measurement points P0, P0. At measurement points P0, P0, the optical path within the pillow packaging bag preferably is a space where the object to be packaged does not obstruct the laser light, as will be described later. This can prevent the object to be packaged from absorbing and scattering the laser light, thereby causing measurement errors.

[0021] As shown in FIGS. 1 and 2, the conveying device 11 has a conveying path composed of a double-belt conveyor 14, an upstream conveyor 50 arranged on the upstream side along the advancing direction of the pillow packaging bag B indicated by arrow A in FIG. 1 with the double-belt conveyor 14 interposed therebetween, and a downstream conveyor 51 arranged on the downstream side. The speed at which the pillow packaging bag B is conveyed on the conveying path is defined as the conveying speed. The double-belt conveyor 14 includes a first belt conveyor 16a and a second belt conveyor 16b arranged in parallel with a gap 15 of a predetermined width therebetween. The first belt conveyor 16a has a belt 17a, a main rotor 18 that rotates the belt 17a, and a driven rotor 19 that is driven via the belt 17a by the rotation of the main rotor 18. The second belt conveyor 16b is similarly configured. The main rotor 18 is configured to be rotatable, for example, by a servo motor (not shown). Thereby, when the main rotor 18 rotates at a predetermined rotational speed, the belts 17a, 17b move at a predetermined speed, and the pillow packaging bag B placed on the belts 17a, 17b is conveyed. The width of the gap 15 can be arbitrarily set between at least the width through which the laser light can pass and the width at which the pillow packaging bag B does not fall. The main rotors 18 of the first belt conveyor 16a and the second belt conveyor 16b are configured to rotate at the same rotational speed in synchronization with each other. Thereby, both belts 17a, 17b sandwiching the gap 15 move in synchronization, and the pillow packaging bag B can be conveyed at a predetermined conveying speed. In addition, since the main rotors 18 of the first belt conveyor 16a and the second belt conveyor 16b are each connected to a servomotor that can rotate forward and backward, the belts 17a and 17b can also be moved in the forward and reverse directions respectively. That is, the first belt conveyor 16a and the second belt conveyor 16b can be made independent of each other. For example, when the belt 17a of the first belt conveyor 16a is moved forward and the belt 17b of the second belt conveyor 16b is moved backward, the posture of the pillow packaging bag B placed on the belts 17a and 17b can be corrected. At this time, for example, by using it in combination with a guide plate configured to sandwich the double belt conveyor 14, the posture of the pillow packaging bag B can be corrected so that the laser light can be easily projected. In this way, the double belt conveyor 14 is arranged in the middle of the carry-out path for carrying out the completed pillow packaging bag B by the conveyor. Therefore, the laser type gas concentration measuring device 10 according to the present embodiment can be applied to either a vertical pillow packaging machine in which the pillow packaging bags B are formed in a longitudinal row or a horizontal pillow packaging machine in which the pillow packaging bags B are carried out in a horizontal row.

[0022] As shown in FIG. 3, the laser generation unit 12 includes a laser light source 20 and a control unit 21 that sets the wavelength of the laser light emitted from the light source 20 to a specific wavelength and adjusts it to a predetermined light intensity. The laser light source 20 is provided with a semiconductor laser element composed of a diode whose wavelength is variable, and is configured to be able to emit laser light in the near-infrared region. The semiconductor laser element according to the present embodiment is a high-output semiconductor laser element called a DFB (Distributed Feed Back) laser. The control unit 21 is configured to adjust the wavelength of the laser light emitted from the semiconductor laser element to a specific wavelength unique to the specific gas to be measured and perform control to amplify it so that the laser light is emitted at a predetermined incident light intensity. In addition, the control unit 21 is configured to output an incident light signal related to the incident light intensity to be emitted to the measurement unit 23. Here, the specific gas measured by the laser-type gas concentration measuring device 10 according to this embodiment is oxygen gas (O2). The absorption wavelength band specific to the oxygen gas is the 760 nm band, and among the plurality of absorption spectra included in the absorption wavelength band, a specific wavelength related to one absorption spectrum is selected as the output wavelength of the laser light. In this embodiment, it is configured to detect oxygen gas that may deteriorate the packaged item due to oxidation, but it is not limited thereto, and the absorption spectrum related to the absorption wavelength band for specifying the gas to be detected can be arbitrarily set.

[0023] As shown in FIG. 3, the laser light receiving unit 13 includes a light receiving sensor 22 that receives the laser light that has passed through the pillow packaging bag B and attenuated, and a measuring unit 23 that measures the gas concentration based on the light receiving signal from the light receiving sensor. The light receiving sensor 22 is an element that converts the transmitted light intensity of the laser light that has passed through the pillow packaging bag into an electrical transmitted light signal, for example, a photodiode. Thereby, the transmitted light intensity of the laser light that has passed through and attenuated inside the pillow packaging bag B can be electrically processed. The measuring unit 23 calculates the transmittance based on the transmitted light signal related to the transmitted light intensity and the incident light signal related to the incident light intensity of the laser light output from the control unit 21 of the laser generation unit 12, obtains the absorbance of the laser light by the specific gas based on the transmittance, and measures the gas concentration of the specific gas inside the pillow packaging bag B based on the absorbance.

[0024] The path through which the laser light passes between the laser generation unit 12 and the laser light receiving unit 13 is defined as the optical path C, and its length is defined as the optical path length L. On the optical path C, there are an atmospheric atmosphere and the pillow packaging bag B. Here, the specific gas exists in the atmospheric atmosphere and remains inside the pillow packaging bag B. The specific gas absorbs the laser light at a predetermined absorption spectrum related to the specific wavelength that constitutes the laser light on its optical path C. Therefore, the laser light is absorbed and attenuated by the specific gas on the optical path C. Then, the laser light attenuated on the optical path C is received by the light receiving sensor 22. The measurement unit 23 is configured to obtain the transmittance from the light intensity before attenuation acquired from the control unit 21 and the transmitted and attenuated transmitted light intensity. The measurement unit 23 is configured to obtain the absorbance indicating how much the specific gas has absorbed the absorption spectrum on the optical path C from the obtained transmittance. Then, based on the obtained absorbance, the measurement unit 23 calculates the total concentration of the specific gas on the optical path C, and from the total concentration, excluding the influence of the concentration of the specific gas present at a substantially constant concentration in the atmospheric atmosphere, measures the concentration of the specific gas remaining in the pillow packaging bag B. When the measured concentration of the residual specific gas is equal to or higher than a predetermined threshold value, assuming that the specific gas, in this embodiment, oxygen gas, remains in the pillow packaging bag B at a concentration equal to or higher than the allowable concentration, the bag product manufactured by packaging the packaged item with the pillow packaging bag B is determined to be a defective product and discharged outside the conveyance path. As described above, the laser-type gas concentration measuring device 10 measures the gas concentration of the specific gas based on the degree of attenuation of the laser light absorbed and attenuated by the specific gas on the optical path C. Therefore, first, when the optical path length L is constant, the measurement accuracy can be improved by increasing the measurement time. Second, by ensuring a longer optical path length L and increasing the degree of attenuation of the laser light, the measurement accuracy can be improved. Here, when the optical path length L is constant and the optical path length L is short, the measurement time can be ensured to be long, and the laser light emitted from the laser generation unit 12 during the measurement time can be reflected one or more times by a plurality of times so that the apparent optical path length L can be increased by receiving the light with the laser light receiving unit 13. Third, by emitting the laser light a plurality of times and obtaining a plurality of measurement values, the measurement accuracy can be improved. This is possible by keeping the optical path length L constant and ensuring a long measurement time, calculating the measurement average value, measurement deviation, measurement error, etc. from the measurement values obtained by emitting the laser light a plurality of times from the laser generation unit 12 during the measurement time, and feeding back those values to the measured values to correct the measurement values. In any of the above cases, in order to improve the measurement accuracy, it is important to ensure a long measurement time and to keep the optical path length L long and constant during the measurement time.

[0025] The laser-type gas concentration measuring device 10 according to this embodiment that operates based on the above principle is configured such that, as shown in FIGS. 1 and 3, the laser generation unit 12 and the laser light receiving unit 13 are arranged to face each other in the vertical direction with the upper surface sides of the belts 17a and 17b of the conveying device 11 sandwiching the gap 15. That is, when the pillow packaging bag B moves from the upstream conveyor 50 onto the belts 17a and 17b of the conveying device 11 and then moves between the laser generation unit 12 and the laser light receiving unit 13, the laser light is configured to pass through the pillow packaging bag B and the gap 15.

[0026] The product inspection process of the pillow packaging bag B using the laser-type gas concentration measuring device 10 having the above configuration will be described with reference to FIGS. 1 and 2. The pillow packaging bag B that is manufactured by packaging the object to be packaged with a predetermined pillow-type packaging machine and sealed is carried out from the packaging machine and placed on the upstream conveyor 50 for conveyance. In FIGS. 1 and 3, the pillow packaging bags B that are divided one by one are illustrated, but it is not limited thereto, and the pillow packaging bag B may be a pillow packaging bag B formed in a continuous packaging state with a plurality of them connected in a row.

[0027] In the product inspection process, processes related to the moving process of moving the pillow packaging bag B to the measurement position, the measurement process of measuring the gas concentration inside the pillow packaging bag B, and the unloading process of unloading the pillow packaging bag B after measurement from the measurement position are performed. The moving process is a process of placing the pillow packaging bag B that has moved on the upstream conveyor 50 onto the conveying path of the double-belt conveyor 14 from the start end 14a and then moving the pillow packaging bag B along the direction of arrow A in FIGS. 1 and 2 as it is, until the measurement points P0, P0 provided on the pillow packaging bag face the laser generation unit 12 and the laser light receiving unit 13. At this time, the belts 17a and 17b may be rotated relatively in the opposite direction to correct the orientation of the pillow packaging bag B. The measurement process is a process of temporarily stopping the double-belt conveyor 14, emitting laser light from the laser generation unit 12 to the pillow packaging bag B, and performing processes related to gas concentration measurement. Since the principle of gas concentration measurement is as described above, the explanation is omitted. At this time, instead of temporarily stopping the double-belt conveyor 14, the laser light may be instantaneously irradiated for measurement. Further, when measuring the gas concentration during the temporary stop, instead of emitting the laser light once, it may be emitted multiple times and the measurement process may be performed multiple times, and from the obtained measurement values, the measurement average value, measurement deviation, measurement error, etc. may be calculated, and these values may be fed back to the measured value to correct the measurement value. The unloading process is a process of, after the measurement process, the servo motor rotating the main rotor 18 and quickly unloading the pillow packaging bag B from the end 14b of the double-belt conveyor 14 to the downstream conveyor 55. At this time, simultaneously with the unloading of the pillow packaging bag B at the measurement location, the next pillow packaging bag B to be measured is loaded from the upstream conveyor 50, and the processes related to the above-described movement process are performed. In this way, the pillow packaging bag B can be continuously measured.

[0028] According to the laser-type gas concentration measurement device 10 according to this embodiment, the laser light receiving unit 13 is arranged in the gap 15 sandwiched between the belts 17a and 17b of the double-belt conveyor 14 configured by arranging the first belt conveyor 16a and the second belt conveyor 16b side by side, thereby configuring the device. As a result, while securing the space to be measured, the device itself can be made compact. Further, the upstream conveyor 50, the downstream conveyor 55 and the conveying device 11 are separated, and the conveying device 11 is used to perform the unloading process and the movement process simultaneously. As a result, compared with operating the belt conveyor at a constant speed and sequentially measuring one by one on the belt of the belt conveyor, it is possible to quickly start the next measurement rather than performing gas concentration measurement, so that the product inspection process can be speeded up.

Example 2

[0029] Next, other embodiments will be described with reference to the accompanying drawings. FIGS. 4 and 5 are explanatory views showing an outline of the configuration of the laser gas concentration measuring device 10A according to the present embodiment.

[0030] The difference in configuration between the laser gas concentration measuring device 10 described in the first embodiment and the laser gas concentration measuring device 10A according to the present embodiment lies in the laser generation unit 12A and the laser light receiving unit 13A. As shown in FIG. 4, the laser generation unit 12A and the laser light receiving unit 13A, which are arranged to face each other in the vertical direction with a gap 15 therebetween, are configured to be movable along a moving path 30 formed along the transport path, from the start end 30a to the end 30b of the moving path 30, at a predetermined moving speed synchronized with the transport speed of the double-belt conveyor 14. Thereby, when the moving speed is synchronized with the transport speed of the double-belt conveyor 14, the laser generation unit 12A and the laser light receiving unit 13A relatively stop with respect to the pillow packaging bag B. When laser light is emitted toward the measurement points P0, P0 at this time, gas concentration measurement can be continuously performed from the start end 14a to the end 14b of the double-belt conveyor 14.

[0031] When the laser generation unit 12A and the laser light receiving unit 13A reach the end 30b of the moving path 30, they have a return path 31 that subsequently returns from the end 30b to the start end 30a of the moving path 30. As shown in FIG. 5, the return path 31 is such that either both or one of the laser generation unit 12A and the laser light receiving unit 13A moves from the start end 31a of the return path 31 upward or downward on the side opposite to the anti-gap 15, moves in a direction parallel to and opposite to the moving path 30, and when reaching above or below the end 31b of the return path 31, moves toward the gap 15 side. That is, it is configured to operate in a gate motion in which either both or one of the laser generation unit 12A and the laser light receiving unit 13A moves in a substantially U-shape. Thereby, it is possible to avoid the pillow packaging bag B discharged from the belts 17a, 17b to the downstream conveyor 55 after measurement, and it is also possible to prevent interference with the belts of the double-belt conveyor, the main rotor 18, and the sub-rotor 19. In addition, as long as the configuration does not interfere with the pillow packaging bag B or the main rotor 18, the sub-rotor 19, etc., the return path 31 may be a path that linearly follows from the end 30b to the start 30a of the movement path 30.

[0032] Next, a product inspection process of the pillow packaging bag B using the laser-type gas concentration measuring device 10A having the above configuration will be described according to FIGS. 4 and 5. In the product inspection process, processes related to a first movement process and a second movement process of moving the pillow packaging bag B to the measurement position, a measurement process of measuring the gas concentration inside the pillow packaging bag B, and a carry-out process of carrying out the pillow packaging bag B after measurement from the measurement position are performed. In the first movement process, the pillow packaging bag B that has moved on the upstream conveyor 50 is placed on the start end 14a of the double-belt conveyor 14, and as shown in FIG. 5, the measurement points P0, P0 provided in front of the pillow packaging bag B are moved to positions facing the laser generation unit 12A and the laser light receiving unit 13A. The subsequent second movement process is performed together with the measurement process. The measurement process is a process of performing a process of emitting laser light to the pillow packaging bag B and measuring the gas concentration inside the pillow packaging bag B. Since the measurement method is the same as that of the first embodiment, the description thereof is omitted. The second movement process is a process of moving the laser generation unit 12A and the laser light receiving unit 13A and the pillow packaging bag B at the same speed. By synchronizing the moving speeds of the laser generation unit 12A and the laser light receiving unit 13A with the conveying speed at which the conveying device 11 conveys the pillow packaging bag B and moving them at the same speed, the laser generation unit 12A relatively stops with respect to the measurement points P0, P0 and can emit laser light without deviating from the measurement points P0, P0, and the laser light receiving unit 13A relatively stops with respect to the measurement points P0, P0 and can receive laser light without deviating from the measurement points P0, P0. Therefore, the measurement time related to the measurement process can be ensured to be long, and the inspection accuracy can be improved. The unloading process is a process of unloading the pillow packaging bag B from the belts 17a and 17b of the double-belt conveyor 14. At this time, since there is a risk that the laser generator 12A may interfere with the unloaded pillow packaging bag B, at least the laser generator 12A is returned so as to draw a gate motion that rises from the end 30b of the movement path 30 and heads toward the end 31b of the return path 31. Thereby, it is possible to prevent the unloaded pillow packaging bag B from interfering with the laser generator 12A. In the product inspection process according to the present embodiment, the measurement points P0 and P0 are set in front of the pillow packaging bag B as shown in FIG. 5. Conversely, they may be set on the rear side. In this case, since the second movement process and the unloading process can be performed simultaneously, when the measurement process is completed, the pillow packaging bag B to be measured has already been unloaded onto the downstream conveyor 55. In this case, at the timing when the laser generator 12A rises along the return path 31, the process related to the first movement process of the next pillow packaging bag B to be measured is performed, and the next pillow packaging bag B to be measured is sent between the laser generator 12A and the upper surfaces of the belts 17a and 17b of the double-belt conveyor. Thereby, it is possible to prevent the pillow packaging bag B set at the measurement position from interfering with the laser generator 12A. In any case, since the pillow packaging bag B on the double-belt conveyor 14 may interfere with the movement of the laser generator 12A, as described above, in the case of the example shown in FIG. 5, at least the laser generator 12A preferably moves along the return path 31 set by the gate motion to the start end 30a of the movement path 30.

[0033] According to the laser type gas concentration measuring device 10A according to the present embodiment, the measurement process and the second movement process are performed in parallel, and the gas concentration inside the pillow packaging bag B is measured while moving the pillow packaging bag B. As a result, a long measurement time can be ensured to improve the inspection accuracy, and the inspection time required for each pillow packaging bag B can be shortened, so that the product inspection process can be speeded up.

Example 3

[0034] Next, other embodiments will be described with reference to the accompanying drawings. FIGS. 6 and 7 are explanatory views showing the outline of the configuration of the laser-type gas concentration measuring device 10B according to the present embodiment.

[0035] The difference in configuration between the laser-type gas concentration measuring device 10 described in the first embodiment and the laser-type gas concentration measuring device 10B according to the present embodiment is that, in addition to the laser generation unit 12B and the laser light receiving unit 13B, it has a reflecting mirror 35. As shown in FIGS. 6 and 7, the laser generation unit 12B and the laser light receiving unit 13B are arranged above the gap 15, and a reflecting mirror 35 is arranged at a position facing the laser generation unit 12B and the laser light receiving unit 13B between the gaps 15. The laser light emitted from the laser generation unit 12B is reflected by the reflecting mirror 35 and reciprocates on the same optical path C. Further, it is configured to be split by a half mirror 36 installed in front of the laser generation unit 12B from the laser light emitted from the laser generation unit 12 and enter the laser light receiving unit 13B. When a specific gas remains in the pillow packaging bag B due to the laser light reciprocating on the same optical path C, the optical path length L can be increased to greatly attenuate the laser light. Also, since the laser light reciprocates on the same optical path C, the bias of specific gas molecules is less than that configured to follow another optical path C after reflection, so the residual concentration can be measured more accurately. In the present embodiment, the laser light reciprocating on the same optical path C is split and configured to enter the laser light receiving unit 13B. However, the present invention is not limited to this, and the laser light may be made to enter the reflecting mirror 35 at a predetermined incident angle and be received by a separately provided laser light receiving unit 13B after being reflected once by the reflecting mirror 35. Since the other configurations and measurement methods are the same as those in the first embodiment, the description thereof will be omitted.

[0036] Next, the product inspection process of the pillow packaging bag B using the laser-type gas concentration measuring device 10B having the above configuration will be described with reference to FIGS. 6 and 7. In the product inspection process, processes related to a moving process of moving the pillow packaging bag B to the measurement position, a measurement process of measuring the gas concentration inside the pillow packaging bag B, and a carrying-out process of carrying out the measured pillow packaging bag B from the measurement position are performed. In the moving process, the pillow packaging bag B that has moved on the upstream conveyor 50 is placed on the starting end 14a of the double-belt conveyor 14, and the pillow packaging bag B is directly moved along the direction of arrow A in the figure to the position between the laser generation unit 12B and the laser light receiving unit 13B and the reflecting mirror 35 at the measurement points P0, P0. In the measurement process, the double-belt conveyor 14 is temporarily stopped, and laser light is emitted from the laser generation unit 12B to the pillow packaging bag B, and a process related to gas concentration measurement is performed. Since the principle of gas concentration measurement is as described above, the description is omitted. At this time, instead of temporarily stopping the double-belt conveyor 14, the laser light may be instantaneously irradiated for measurement. Further, when measuring the gas concentration during the temporary stop, instead of emitting the laser light once, the laser light is emitted multiple times and the measurement process is performed multiple times, and from the obtained measurement values, a measurement average value, a measurement deviation, a measurement error, etc. are calculated, and these values are fed back to the measured value to correct the measurement value. In the carrying-out process, after the measurement process, the servo motor rotates the main rotor 18, and a process of quickly carrying out the pillow packaging bag B from the terminal end 14b of the double-belt conveyor 14 to the downstream conveyor 55 is performed.

[0037] According to the laser-type gas concentration measuring device 10B according to the present embodiment, the laser generation unit 12B and the laser light receiving unit 13B are arranged on the same side, and are configured as a reflection type in which the reflected light reflected by the reflecting mirror 35 is spectroscopically separated and incident on the laser light receiving unit 13B. As a result, even in a place where there is no space margin below the double-belt conveyor 14, the conveying device 11 according to the present embodiment can be installed to measure the gas concentration by laser light.

Example 4

[0038] Next, other embodiments will be described with reference to the accompanying drawings. FIGS. 8 and 9 are explanatory diagrams showing the schematic configuration of the laser-type gas concentration measuring apparatus 10C according to the present embodiment.

[0039] The difference in configuration between the laser-type gas concentration measuring apparatus 10 described in the first embodiment and the laser-type gas concentration measuring apparatus 10C according to the present embodiment is that, in addition to the laser generation unit 12C and the laser light receiving unit 13C, it has a main reflecting mirror 36 and a sub-reflecting mirror 37. As shown in FIG. 8, the laser generation unit 12C is disposed near the start end 14a side of the double-belt conveyor 14 above the gap 15, and the laser light receiving unit 13C is disposed near the end 14b side of the double-belt conveyor 14. Further, as shown in FIG. 9, in the gap 15, a strip-shaped main reflecting mirror 36 is disposed from the vicinity of the start end 14a to the vicinity of the end 14b of the double-belt conveyor 14. Then, as shown in FIG. 9, a strip-shaped sub-reflecting mirror 37 is disposed opposite to the main reflecting mirror 36 at a position opposite to the main reflecting mirror 36 between the laser generation unit 12 and the laser light receiving unit 13. Thus, the laser light emitted from the laser generation unit 12 at a predetermined angle is configured to be incident on the laser light receiving unit 13 after being reflected a plurality of times between the main reflecting mirror 36 and the sub-reflecting mirror 37. In this way, by reflecting the laser light between the main reflecting mirror 36 and the sub-reflecting mirror 37, the optical path length can be ensured to be long, and when a specific gas remains in the pillow packaging bag B, the laser light can be greatly attenuated. Note that the measurement points P0, P0 of the pillow packaging bag B measured by the laser-type gas concentration measuring apparatus 10C according to the present embodiment are set corresponding to the optical path C through which the laser light is reflected a plurality of times and passes through the inside of the pillow packaging bag, as shown in FIG. 9. Thus, for example, as in the measurement points P0, P0 shown in FIG. 1 according to the first embodiment, it is difficult to aim at the space without the packaged product by providing them to face each other between one film and the other film constituting the bag. Therefore, in order to allow the laser light to be reflected a plurality of times inside the pillow packaging bag B, it is preferable to form a space through which the laser light passes, for example, by making the inside center of the pillow packaging bag B air-permeable and partitioning it along the longitudinal direction. Since the other configurations and measurement methods are the same as those of the first embodiment, the description thereof will be omitted.

[0040] Next, a product inspection process of the pillow packaging bag using the laser gas concentration measuring device 10C having the above configuration will be described with reference to FIGS. 8 and 9. In the product inspection process, processes related to a moving process of moving the pillow packaging bag B to the measurement position, a measurement process of measuring the gas concentration inside the pillow packaging bag B, and a carrying-out process of carrying out the pillow packaging bag B after measurement from the measurement position are performed. The moving process is a process of placing the pillow packaging bag B that has moved on the upstream conveyor 50 on the start end 14a of the double-belt conveyor 14 and moving it along the direction of arrow A in the figure as it is so that the pillow packaging bag B is placed on the belts 17a and 17b. The measurement process is a process of temporarily stopping the double-belt conveyor 14, sandwiching the pillow packaging bag B between the sub-reflector 37 and the belts 17a and 17b, and preferably also sandwiching the main reflector 36, bringing the reflecting surfaces of the main reflector 36 and the sub-reflector 37 into contact with the pillow packaging machine B, and then injecting laser light from the laser generation unit 12C to the pillow packaging bag and performing processing related to gas concentration measurement. Since the gas concentration measurement method is as described above, the description thereof will be omitted. When measuring the gas concentration, instead of injecting the laser light once, it may be injected multiple times and the measurement process may be performed multiple times, and from the obtained measurement values, a measurement average value, a measurement deviation, a measurement error, etc. may be calculated, and these values may be fed back to the measured value to correct the measured value. The carrying-out process is a process of, after the measurement process, rotating the main rotor 18 by the servo motor and quickly carrying out the pillow packaging bag B from the end 14b of the double-belt conveyor 14 to the downstream conveyor 55.

[0041] According to the laser gas concentration measuring device 10C according to this embodiment, the main reflector 36 is installed in the gap 15 of the conveying device 11, and the pillow packaging bag B to be measured placed on the belts 17a and 17b is pressed by the sub-reflector 37, and the pillow packaging bag B is sandwiched between the main reflector 36 and the sub-reflector 37 for measurement. Thus, the optical path length L can be lengthened, so that the measurement accuracy can be improved.

[0042] According to the laser gas concentration measuring devices 10, 10A, 10B, and 10C according to the first to fourth embodiments, a conveying device 11 having a double-belt conveyor 14 is provided between the upstream conveyor 50 and the downstream conveyor 55. When measuring the residual gas concentration in the pillow packaging bag B on the belts 17a and 17b, the laser light receiving part, the reflector 35, and the main reflector 36 are arranged in the gap 15 formed between the belts 17a and 17b for measurement using the gap 15. Then, when the pillow packaging bag B is carried into and out of the belts 17a and 17b, the previous pillow packaging bag B can be carried out and at the same time the next pillow packaging bag B to be measured can be quickly carried in and replaced. Also, by quickly performing the stop and operation periodically, the speed can be increased compared to performing the measurement while the pillow packaging bag is placed on the belt conveyor. In addition, a laser gas concentration measuring device can be incorporated in the middle of the conveyance path where the bag products related to the pillow packaging bags manufactured by the pillow packaging machine are carried out. Also, it is not limited to the pillow packaging bag, and even for ordinary packaging bags, trays or packaging containers such as cups, they can be provided in the middle of the conveyance path for carrying out those products. Therefore, the laser gas concentration measuring device according to this embodiment has excellent versatility.

Explanation of Reference Numerals

[0043] 10, 10A, 10B, 10C... Laser gas concentration measuring device, 11... Conveying device, 12, 12A, 12B, 12C... Laser generating part, 13, 13A, 13B, 13C... Laser light receiving part, 14... Double-belt conveyor, 15... Gap, 16a... First belt conveyor, 16b... Second belt conveyor, 17a, 17b... Belts, 18... Main rotor, 19... Driven rotor, 20… Laser light source, 21… Control unit, 22… Light receiving sensor, 23… Measuring unit, 30… Moving path, 31… Return path, 35… Reflecting mirror, 36… Main reflecting mirror, 37… Sub-reflecting mirror, 50… Upstream conveyor, 55… Downstream conveyor, A… Direction in which the pillow packaging bag is conveyed, B… Pillow packaging bag, C… Optical path, L… Optical path length, P0… Measurement point

Claims

1. A conveying device comprising a conveying path consisting of a conveyor on which gas-replaced and sealed packaging bags, packaging containers, or similar packages are placed, and conveying the packages at a predetermined conveying speed, A laser gas concentration measuring device composed of a laser generating unit that emits laser light of a specific wavelength and a laser receiving unit that receives the laser light, A double-belt conveyor composed of a first belt conveyor and a second belt conveyor arranged in parallel with a gap of a predetermined width in the middle of the conveying path is provided, A moving path is provided in which the laser generating unit and the laser receiving unit arranged opposite to each other in the vertical direction with the gap therebetween move in parallel with respect to the conveying path from the start end to the end of the double-belt conveyor at a moving speed synchronized with the conveying speed, When the packages being conveyed on the conveying path are placed on the double-belt conveyor, The laser generating unit and the laser receiving unit moving along the moving path stop relatively with respect to a measurement point provided on the packages, The laser light emitted from the laser generating unit passes through the packages and the gap and is received by the laser receiving unit, A laser gas concentration measuring device characterized in that the gas concentration of a specific gas remaining in the packages is measured based on an absorption spectrum of the specific wavelength that changes before and after passing through the packages.

2. When the laser generating unit and the laser receiving unit reach the end of the double-belt conveyor, The laser gas concentration measuring device according to claim 1, characterized in that a return path is provided in which both or either one of the laser generating unit and the laser receiving unit return from the end to the start end along a substantially U-shaped locus along the vertical direction on the opposite side of the gap.

3. A conveying device comprising a conveying path composed of a conveyor on which gas-replaced and sealed packaging bags or packaging containers or similar packages are placed, and conveying the packages at a predetermined conveying speed, A laser gas concentration measuring device comprising a laser generating unit that emits laser light of a specific wavelength and a laser receiving unit that receives the laser light, In the middle of the conveying path, a double-belt conveyor composed of a first belt conveyor and a second belt conveyor arranged in parallel with a gap of a predetermined width therebetween is provided, A main reflector is arranged in the gap, When the packages being conveyed on the conveying path are placed on the double-belt conveyor, The laser light emitted from the laser generating unit passes through the packages and the gap, is reflected by the main reflector, and then received by the laser receiving unit, A laser gas concentration measuring device characterized by measuring the gas concentration of a specific gas remaining in the packages based on the absorption spectrum of the specific wavelength that changes before and after passing through the packages.

4. The laser gas concentration measuring device according to claim 3, characterized in that the laser light emitted from the laser generating unit is reflected by the main reflector and travels on the same optical path to be received by the laser receiving unit.

5. A sub-reflector that faces the main reflector in parallel with the packages interposed therebetween is arranged opposite to the main reflector, The laser gas concentration measuring device according to claim 3, characterized in that the laser light emitted from the laser generating unit is reflected between the main reflector and the sub-reflector and then received by the laser receiving unit.

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