JP2001058609A - Device and method for substituting gas in can - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas substituting device and a substituting method for sufficiently substituting air in a head space with substituting gas even when the head space of a can is large. SOLUTION: An inert gas substituting device 1 is provided with an inert gas feed section 6 for feeding continuously an inert gas GN2 from above a can 2, a liquefied inert gas feed section 7 for feeding a liquefied inert gas LN2 and a seamer gas feed section 9 for feeding the inert gas GN2 into the can 2 just before rolling a can cover, and all above feed sections are kept in the half-closed space state by an outer cover 4. The gas substitution is carried out to a certain extent by carrying the can 2 to a conveyor 3, and also the inert gas GN2 is fed on the seamer gas feed section 9 to sufficiently carry out the gas substitution of a head space 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas replacement device and a replacement method for replacing air in a head space of a can filled with contents with a replacement gas.

[0002]

2. Description of the Related Art In the production of canned food contents liquids such as soft drinks and coffee drinks, in order to prevent the quality of the contents liquid from deteriorating due to the influence of oxygen, the head space of the can after the contents liquid has been stored is required. It is widely practiced to replace the air with an inert gas such as nitrogen gas and then wind and seal the can lid.

[0003] The replacement of the inert gas in such canning production is carried out, for example, as disclosed in JP-B-58-15363, by supplying liquid nitrogen into the head space of the can immediately before tightening the can lid. Liquid nitrogen is added to the head space of the can in a nitrogen-filled canned production line, and then an inert gas is blown into the head space immediately before the can lid is covered with a winder, so that the air in the head space is inert gas. Is known.

As shown in FIG. 8, an apparatus for replacing an inert gas in a can disclosed in Japanese Patent Application Laid-Open No. 1-99922 can continuously rotate a can 62 in which contents are accommodated and whose upper surface is open. (Conveyer) 64 to be transported to a (can seamer) 64, and a head space 62 of a transported can disposed at a predetermined interval from the can winding machine 64 in the transport path of the conveyor 52.
liquefied inert gas addition device 53 for adding liquefied inert gas LN2 to a, and undercover gassing device 56 arranged on the way of lifter 55 of can winder 64
And The transport route of the conveyor 52 is surrounded by a tunnel 60. Here, the can 62 is the conveyor 5
Upstream of the liquefied inert gas LN2, the liquefied inert gas LN2 is added from the liquefied inert gas addition device 53.
Is the headspace 6 of the can 62 being transported by the conveyor 52.
It is vaporized in 2a and converted into an inert gas GN2.
Immediately before the can lid 63, which is disposed on the lifter 55 and supported by the can lid holder 57, is wound, the gas from the gas outlet 58 formed in the chamber body 59 of the undercover gassing device 56 does not reach the head space 62a. The active gas GN2 is supplied, and the can 65 is tightly wound by the chuck 65. An inert gas blowing device 61 is provided above the tunnel 60.

[0005]

In the case of a low-strength can, for example, an aluminum two-piece can, the purpose is to stabilize the internal pressure of the can and also to prevent the contents from being spilled. Therefore, a large head space is provided. Therefore, the amount of oxygen existing in the head space is inevitably increased, and the conventional apparatus and method for inert gas replacement of cans cannot sufficiently perform gas replacement in the head space. Contents that are susceptible to deterioration due to the influence of oxygen, such as juices and fruit drinks or tea drinks, cannot be adequately handled.

[0006] The present invention has been made in view of such circumstances, and a gas replacement device for a can which can sufficiently replace the air in the headspace with an inert gas even in the case of a can having a large head space. And a replacement method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a can gas replacement apparatus for replacing air in a head space of a can filled with contents with a replacement gas. A conveyor for accommodating the contents and continuously transporting the cans having an open top to the can seamer portion, and an outer cover for keeping the transport route of this conveyor in a semi-enclosed space immediately before the can seamer portion. A replacement gas supply unit provided at a plurality of locations along the transport path, for continuously supplying a replacement gas from above the can in the outer cover, and the replacement gas supply unit; A filter section for reducing the flow velocity of the replacement gas disposed between the can and the can along the transport path.

According to the present invention, the replacement gas is supplied from the seamer gas supply section to the head space of the can immediately before being conveyed to the can seamer section and the can lid is tightened, and the head is moved along the conveying path of the upstream conveyor. By installing a replacement gas supply unit for continuously supplying a replacement gas from above the can, which is provided at a plurality of locations along the transport path as a gas pre-replacement means in the space, the can in the head space of the can The air is naturally replaced by the replacement gas simply by being transported on the conveyor. Therefore, the amount of oxygen in the head space is reduced, and deterioration of the contents due to oxygen is prevented. At this time, the replacement gas is an inert gas or a carbon dioxide gas.

In addition, the seamer gas supply section for supplying a replacement gas to the head space just before the can lid is wound around the opening of the can is provided in the can seamer section, so that the can seam is conveyed on the conveyor. The head space partially replaced by the replacement gas by the replacement gas is sufficiently replaced by the replacement gas by the replacement gas supplied from the seamer gas supply unit. Therefore, the amount of oxygen in the head space is sufficiently reduced, and deterioration of the contents due to oxygen is prevented.

Further, since the transfer path is kept in a semi-enclosed space by the outer cover, gas replacement can be performed in a stable replacement gas atmosphere.

The replacement gas supplied from the replacement gas supply unit passes through a filter unit disposed above the can along the transport path, and is then supplied to the head space of the transported can. Has become. Therefore, the replacement gas that has passed through the filter section is uniformly supplied while diffusing into the transfer path maintained in the semi-enclosed space, and the inert gas atmosphere inside the transfer path becomes uniform, thereby replacing the gas in the head space. It can be performed stably.

[0012] The replacement gas that has passed through the filter section is placed in a .0.
5 m / sec. By supplying to the head space of the can at the following flow rate, the air in the head space is replaced stably. In other words, when the replacement gas is supplied at a high flow rate, the replacement gas interferes with the airflow generated by the transported can, so that the replacement gas is not stably supplied into the head space. Therefore, the flow rate of the replacement gas is set to 0.5 m
/ Sec. By supplying at the following low speed, gas replacement is performed stably.

[0013] By using a sintered filter formed of a mesh of 2 to 10 µm in the filter portion, the replacement gas is sufficiently diffused by passing through the sintered filter and then supplied to the transport path. You.

A liquefaction / replacement gas supply section is provided in the middle of the transport path, and the liquefaction / replacement gas supply section supplies the liquefaction / replacement gas to the head space to vaporize the liquefaction / replacement gas during transportation. Thereby, gas replacement of the head space can be performed more reliably.

[0015] By providing a narrowing plate formed at the lower end of the filter section so as to extend to the side wall of the can to be conveyed, the space between the upper end of the can and the filter section becomes smaller, and Gas is supplied stably toward the head space.

[0016] A gas replacement method for a can for replacing air in a head space of a can filled with contents with a replacement gas, wherein a conveying path maintained in a semi-enclosed space is directed toward a can seamer portion. To be continuously conveyed, to the head space of the can that contains the contents and is open at the top, while continuously supplying the replacement gas that has passed through the filter unit installed along the conveyance path, By gas replacement by a gas replacement method for a can, characterized in that a replacement gas or a liquefaction replacement gas is supplied to the headspace in the can seamer immediately before the can lid is fastened to the opening of the can. The gas can be replaced to some extent only by passing through the transport path, and the gas for replacement is supplied immediately before the can lid is wound tightly. Replacement gas is fully charged, the deterioration of the contents thereof in the reactor after sealing the can lid is wound up is prevented. At this time, the replacement gas is an inert gas or a carbon dioxide gas.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an apparatus and method for gas replacement of a can according to an embodiment of the present invention. FIG. 1 is a side view showing the overall configuration of a can gas replacement device of the present invention, and FIG. 2 is a first inert gas replacement portion A of FIG.
It is an enlarged view of a part. In the present embodiment, the replacement gas is an inert gas, but may be a carbon dioxide gas.

In FIG. 1, an inert gas replacement device (gas replacement device) 1 includes a conveyor 3 for transporting a can 2 having an open top, and an inert gas installed along the longitudinal direction of the conveyor 3. A first inert gas replacement section A, a second inert gas replacement section B, a third inert gas replacement section C for supplying a gas (replacement gas) GN2, and a seamer gas supply provided in the can seamer section 8 And a section 9. A liquefied inert gas supply unit 7 for supplying a liquefied inert gas (liquefied replacement gas) LN2 is provided between the second inert gas replacement unit B and the third inert gas replacement unit C. ing.

The can 2 is formed in a cylindrical shape with a bottom by, for example, an aluminum alloy, and has an opening 10 at an upper end as shown in FIG. Inside the can 2, there is a conveyor 3
A content 2a such as a liquid for beverage is accommodated by a content filling machine (not shown) provided on the upstream side of the container. A head space 11 is formed between the contents 2a and the upper end of the can 2. The can 2 is conveyed to the can seamer section 8 for winding the can lid around the opening 10 while being kept in an upright state by the conveyor 3.

As shown in FIGS. 1, 2 and 3, an outer cover 4 is provided along the longitudinal direction of the conveyor 3. As shown in FIG. 3, the outer cover is formed in a substantially U-shape that is open downward in cross section, and its lower end extends to the vicinity of the conveyor 3. Then, the transport path of the conveyor 3 is maintained in a semi-closed space state.

As shown in FIG. 2, the first inert gas replacement section A is provided with inert gas supply sections (replacement gas supply sections) 6 at a plurality of locations along the conveying path of the conveyor 3.
The inert gas supply units 6 are installed at intervals on the ceiling 4a of the outer cover 4, and are installed, for example, at two to four locations per meter. From the inert gas supply unit 6, an inert gas G such as nitrogen gas is continuously injected vertically downward, and is supplied from above the can 2 to which the conveyor 3 is conveyed. The ceiling portion 4a is rotatably supported by a hinge portion 4b as shown in FIG. 3, and rotates between 4a and 4a 'in FIG.
It can be opened and closed above.

Below the inert gas supply unit 6, a plate-shaped sintered filter 12 formed in a rectangular shape in a plan view is provided in a plurality of stages so as to cover the entire upper portion of the can 2 along the transport direction of the can 2. is set up. The height between the top and bottom is 100
mm. A space 13 is formed between the inert gas supply unit 6 and the uppermost stage of the sintered filter 12.

The sintered filter 12 has a mesh of 2
A 10 μm mesh, preferably a 5 μm mesh mesh is used. Each of the plurality of engaging portions 14 a formed in a concave cross section of the filter support portion 14 formed to extend inward from the side wall portion of the outer cover 4. Supported. The sintered filter 12 is arranged so that the distance between the lowermost stage and the upper end of the conveyed can 2 is about 10 to 40 mm.

The inert gas GN2 supplied from the inert gas supply unit 6 is temporarily stored in the space 13 and
3 is placed under an inert gas G atmosphere, and the pressure is slightly increased. The inert gas GN2 is supplied above the can 2 which is conveyed through the sintered filters 12 installed in a plurality of stages by the minute pressure. At this time, the inert gas GN2 that passed through the sintered filter 12 was 0.5 m / sec. It is set so as to be supplied at the following flow rate, preferably 0.1 m / sec. It is supplied at a flow rate of.

From the vicinity of the lower end of the filter support 14,
Two tongue-shaped guide plates 15 are formed so as to extend near the side wall of the can 2 to be conveyed. Similarly, from the vicinity of the lower end of the filter support portion 14, a narrowing plate 17 formed to extend near the side wall of the can 2 to be conveyed is provided along the direction of the conveyance path. This narrowing plate 17
The plane portion is installed so as to be parallel to the direction of the transport path of the conveyor 3, and its cross-sectional shape is formed in a U-shaped cross-section so as to approach the side wall of the can 2 from the filter support portion 14. It is provided apart from the side wall so as not to hinder the transport of the can 2.

The inert gas supply unit 6 having such a configuration, the sintered filter 12 and the narrowing plate 17 are provided in the second
The inert gas replacement section B and the third inert gas replacement section C are similarly arranged. The installation length of the first, second, and third inert gas replacement units A, B, and C is set as long as possible within a mountable range to sufficiently replace the inert gas GN2 in the head space 11. But can be done
In consideration of cost aspects such as the consumption amount of the inert gas GN2, it is desirable to provide each of them at about 0.5 to 1.5 m.

As shown in FIGS. 1, 2 and 4, an inert gas curtain forming section 5 is provided at the most upstream portion of the first inert gas replacing section A. The inert gas curtain forming section 5 has an upper jetting section 5 provided above the transport path entrance end for continuously blowing the inert gas GN2.
a and side ejection parts 5b provided at two places on the left and right. Of these, the upper ejection part 5a is provided for the transported can 2
The inert gas GN2 is continuously blown out vertically from above and toward the upstream side of the transport path, and the side ejection portion 5b is provided radially inward of the transport path and upstream of the transport path. It blows out continuously. Each of the ejection parts 5a and 5b is formed in a slit shape having a width of about 0.5 to 1.0 mm.
The distance between 5b and the transported can 2 is set to about 10 mm. Then, the head space 1 of the transported can 2
1 to supply inert gas GN2 and prevent air from entering the inside of the first inert gas replacement section A, thereby maintaining the inert gas atmosphere inside each of the inert gas replacement sections A, B, and C. It is made to let.

A liquefied inert gas supply unit 7 is provided between the second inert gas replacement unit B and the third inert gas replacement unit C. From the liquefied inert gas supply unit 7, a liquefied inert gas LN2 such as liquid nitrogen is supplied from the opening 10 of the transported can 2 into the head space 11.

Downstream of the third inert gas replacement section C, a can seamer section 8 for winding the can lid around the opening 10 of the transported can 2 is provided. A lifter 16 is installed in the can seamer section 8, and the transported can 2 is supported by the lifter 16, transported to the can seamer section 8, and the can lid is fastened.

The can 2 is provided with a can 16
A seamer gas supply unit 9 for supplying the inert gas GN2 to the head space 11 of the can 2 is installed on the way to the head space 11. The inert gas GN2 is finally supplied from the seamer gas supply unit 9 to the can 2 to which the conveyor 3 has been transported. The lifter 16 and the seamer gas supply unit 9 are also surrounded by the outer cover 4.

The first, second, and third inert gas replacement sections A, B, and C, the liquefied inert gas supply section 7, the lifter 16, and the seamer gas supply section 9 are connected to each other by the outer cover 4. It is covered and maintains a semi-closed space.

In order to replace the air in the head space 11 of the can 2 with the inert gas GN2 by using the inert gas replacing apparatus 1 for a can having such a structure, first, a can filling apparatus (not shown) is used. The contents 2a are accommodated through the second opening 10. At this time, in order to prevent the contents 2a from spilling or to stabilize the internal pressure of the sealed can 2, the contents 2a are accommodated with some margin. At this time, a head space 11 is formed between the upper surface of the contents 2a and the upper end of the can 2.

The can 2 containing the contents 2a is a conveyor 3
And is transported downstream to enter the first inert gas replacement section A. An inert gas curtain forming part 5 is formed on the inlet side of the first inert gas replacing part A, and the inert gas GN2 is directed from above from the upper ejection part 5a so as to head toward the opening 10 of the can 2. Since the air is blown out, first, the inert gas GN2 is supplied to the head space 11 at this stage. Further, since the inert gas GN2 is ejected to the outside of the first inert gas replacement section A together with the inert gas GN2 ejected from the side ejection section 5b, the first inert gas GN2 is ejected from the inlet side. Intrusion of air into the active gas replacement section A is prevented. Therefore, the first inert gas replacement part A and the second and third inert gas replacement parts B and C downstream thereof can stably maintain the inert gas GN2 atmosphere.

The can 2 having passed through the inert gas curtain forming section 5 is transported to the first inert gas replacing section A and the second inert gas replacing section B. At this time, head space 1 of can 2
1, the inert gas GN2 is continuously supplied from the inert gas supply unit 6 located above.

This inert gas GN2 fills one end of the space 13 shown in FIG. 3 to make the atmosphere of the inert gas GN2. Sintered filter 1 arranged below space 13
In No. 2, since the mesh is formed to have a thickness of 2 to 10 μm, a slight resistance is generated when the inert gas GN2 passes. Therefore, the pressure in the space 13 is slightly increased, and the passage of the sintered filter 12 is performed by a pressure difference between the space 13 and a position below the sintered filter 12.

Since the inert gas GN2 is dispersed by passing through the sintered filter 12, the first, second and third inert gases GN2 are dispersed.
The gas atmosphere inside the inert gas replacement sections A, B, and C is made uniform.

Then, the can 2 is transported at a speed of, for example, about 1.6 m / s. From above the can 2, a sintered filter 1
2 of inert gas GN2 passing through 0.5 m / sec. At a flow rate of 0.1 m / sec. , The can 2 can obtain a replacement effect of, for example, about 60 to 70% only by passing through the replacement sections A, B, and C.

The can 2 is conveyed to the downstream side while the inert gas GN2 is supplied from above. Second inert gas replacement section B
A liquefied inert gas LN2 such as liquid nitrogen is supplied to the head space 11 of the can 2 from a liquefied inert gas supply unit 7 installed on the downstream side of. The liquefied inert gas LN2 supplied to the head space 11 is conveyed inside the third inert gas replacement section C and is vaporized before the can lid is tightly wound by the can seamer section 8, and the corner of the head space 11 is formed. The inert gas GN2 is spread to various parts.

The air in the head space 11 can be sufficiently replaced with the inert gas GN2 only by the inert gas replacement units A, B and C without providing the liquefied inert gas supply unit 7. When the liquefied inert gas supply unit 7 is combined as in this embodiment, the liquefied inert gas LN2 is completely vaporized and the head space 11 is filled with the inert gas GN2 downstream of the liquefied inert gas supply unit 7. In order to satisfy the condition, it is preferable to secure a transport path for supplying the inert gas GN2 such as the third inert gas replacement unit C.

The can 2 having passed through each of the inert gas replacement sections A, B and C and the liquefied inert gas supply section 7 is placed on a lifter 16 and supplied to the can seamer section 8 by raising the lifter 16. You. The can seamer section 8 is provided with a seamer gas supply section 9, from which the head is supported immediately before the can lid supported by the can lid holder of the can seamer section 8 is mounted on the opening 10. The inert gas GN2 is supplied to the space 11. And can 2
Immediately after the inert gas GN2 is supplied to the head space 11 by the seamer gas supply unit 9, the can lid is wound around by the chuck.

Thus, the inert gas replacement device 1
The air in the head space 11 is replaced with the inert gas GN2 by about 60 to 70% by the first, second, and third inert gas replacement units A, B, and C, and the seamer gas supply unit 9 is further combined. Finally, gas replacement of about 96% can be performed.

As described above, the inert gas GN2 is supplied from the seamer gas supply unit 9 to the head space 11 of the can 2 immediately before being conveyed to the can seamer unit 8 and the can lid is tightened, and the conveying path of the conveyor 3 upstream thereof. In the above, the inert gas GN2 in the head space 11 of the can 2 is provided as a preliminary replacement means near the end of the outer cover 4 on the entrance side of the transport path, and the inert gas GN2 is blown near the end. The gas curtain forming unit 5, the inert gas supply unit 6 for continuously supplying the inert gas GN <b> 2 provided at a plurality of locations along the conveyance path from above the opening 10 of the can 2, and the conveyance of the conveyor 3. Since the liquefied inert gas supply unit 7 for supplying the liquefied inert gas LN2 to the head space 11 is provided in the middle of the path, the head space 1 Air inside is replaced by a natural inert gas GN2 is conveyed on the conveyor 3.

Then, the head space 11 conveyed on the conveyor 3 and replaced with the inert gas GN2 to some extent.
Is sufficiently inert gas G by the seamer gas supply unit 9.
It is replaced with N2, and the oxygen amount in the head space 11 is sufficiently reduced. Therefore, deterioration of the contents 2a due to oxygen can be prevented.

Further, since the transfer path is kept in a semi-enclosed space by the outer cover 4, gas can be replaced in a stable inert gas atmosphere. further,
Since the inert gas curtain forming portion 5 is provided at the end of the outer cover 4 on the entrance side of the transfer path, air is prevented from entering the inside of the transfer path maintained in the semi-enclosed space, and the inside of the transfer path is prevented. The active gas atmosphere is stably maintained.

A sintering filter 12 is provided below the inert gas supply section 6 along the transport path, and the inert gas GN 2 is supplied to the head space 11 after passing through the sintering filter 12. . This sintered filter 12
The inert gas GN2 supplied from the inert gas supply unit 6 to the space 13 slightly raises the pressure in the space 13 to form a 10 μm mesh, preferably a 5 μm mesh. The GN2 passes through the sintered filter 12 while being diffused by the pressure difference. Therefore, the gas atmosphere of the transport path maintained in the semi-enclosed space becomes uniform, and the replacement of the inert gas GN2 in the head space 11 is performed stably.

Further, by disposing the sintered filter 12 at a position 10 to 40 mm above the upper end of the can 2, the inert gas GN2 can be efficiently and reliably supplied to the head space 11.

Further, a squeezing plate 17 extending to the side wall of the conveyed can 2 is provided at the lower end of the sintered filter 12 so as to be separated from the side wall, so that the upper end surface of the can 2 can be sintered. The space between the filter 12 becomes smaller,
The inert gas GN2 is stably supplied to the head space 11.

Inert gas G passing through sintered filter 12
N2 is 0.5 m / sec. At a flow rate of 0.1 m / sec. By supplying the gas at a flow rate of, the gas replacement in the head space 11 is performed stably. This is because, when the flow rate of the inert gas GN2 passing through the sintered filter 12 is high, for example, as shown in FIG. The flow of the active gas GN2 flows downward from above. And can 2 to be transported
As a result, the horizontal airflow generated by the airflow and the vertical airflow from the sintering filter 12 merge, and the flow in the area 101 near the opening 10 of the can 2 becomes faster. Then, the speed difference between the area inside the head space 11 and the airflow in the range 101 becomes, for example, 1.5 m / sec. Accordingly, the head space 11 becomes a stagnant area, and the inert gas GN2 supplied from the sintered filter 12 does not reach the inside of the head space 11.

However, the flow rate of the inert gas GN2 supplied from the sintering filter 12 is set to 0.5 m / sec. And preferably 0.1 m / sec. For example, as shown in FIG. 6, a phenomenon in which the flow velocity in the vicinity of the opening 10 increases due to interference between the airflow in the transport direction generated by the transport of the can 2 and the inert gas GN2 from the sintered filter 12, as shown in FIG. Disappears. Therefore, the air flow inside the head space 11 does not stagnate, and the supplied inert gas GN
2 is circulated stably to every corner of the head space 11.

FIG. 7 shows the experimental results. Among them, FIG.
(A) shows the inert gas G supplied from the sintered filter 12.
FIG. 7B shows an oxygen concentration distribution inside the head space 11 when the flow rate of N2 is small, and FIG.
2 shows the oxygen concentration distribution inside the head space 11 when the flow velocity is large. The horizontal axis of each graph represents an observation position in the direction of the transport path of the inert gas replacement device 1, and the observation is performed at five points from the entrance side to the exit side of the transport path. In each graph, a line P represents an upper oxygen concentration P (%) at an upper end portion of the head space 11 of the can 2 at each observation position, and a line Q represents a lower oxygen concentration near the surface of the content inside the head space 11. Oxygen concentration Q (%)
Is represented. The measurement of the oxygen concentration was performed by installing sensors at the positions inside the respective head spaces 11.
Line R represents the sintered filter 12 measured at each observation position.
Represents the flow rate R (m / s) of the inert gas GN2 supplied from. The ratio of oxygen in the air at this time was 2
0.9%.

As shown in FIG. 7 (a), when the flow rate R is a low speed of about 0.1 m / s or less on the entrance side of the transport path, the upper oxygen concentration P is about 8%, and the lower oxygen concentration P is about 8%. Q was about 19%. From this, it can be seen that if the flow velocity R is small, the upper oxygen concentration P can be slightly reduced even at the entrance position. By transporting the can 2 downstream while supplying the inert gas GN2,
The inert gas GN2 is stably supplied into the head space 11, and the lower oxygen concentration Q gradually decreases. By the time the can 2 is transported to the center of the transport path, the difference between the upper oxygen concentration P and the lower oxygen concentration Q has almost disappeared. Further, the upper and lower oxygen concentrations P and Q show low concentrations from near the center to the outlet side, and it can be seen that gas replacement is performed stably and reliably.

On the other hand, when the flow rate of the inert gas GN2 supplied from the sintering filter 12 is high, the headspace 1
The upper and lower oxygen concentrations P and Q of 1 do not show stable behavior. That is, as shown in FIG. 7B, when the flow velocity R is as high as about 0.5 m / s on the entrance side of the transport path,
Upper oxygen concentration P is about 15%, lower oxygen concentration Q is about 19%
It can be seen that gas replacement is hardly performed. Also, as shown in FIG. 7 (b), when the flow velocity R is always as high as 0.3 m / s or more over the entire transport route, the lower oxygen concentration Q shows a high value of about 8% even near the center of the flow path. Thus, it can be seen that the lower oxygen concentration Q is not reduced until near the outlet side, and the gas replacement inside the head space 11 is not performed stably.

That is, when the inert gas GN2 is supplied at a high flow rate, the gas flow generated by the transported can 2 and the supplied inert gas GN2 interfere with each other, and the inert gas GN2 is supplied to the head space 11. Will not be supplied stably. Therefore, the supplied inert gas GN2
At a flow rate of 0.5 m / sec. Below, preferably 0.1 m
/ Sec. By supplying at the following low speed, the replacement of the inert gas GN2 is performed stably.

The liquefied inert gas L is supplied to the can 2 transported while supplying the inert gas GN2 that has passed through the sintering filter 12 in the transport path in the semi-closed space state.
By supplying N2 and further supplying inert gas GN2 immediately before the can lid is wound around the can 2 in the can seamer section 8, the headspace 11 is filled with the inert gas GN2 to every corner. Table 1 shows the experimental results for verifying this.

[Table 1]

Table 1 shows immediately before the can seamer portion 8 (downstream of the third replacement portion C) when the configuration of the inert gas replacement portion upstream of the can seamer portion 8 and the gas supply amount in the seamer gas supply portion 9 were respectively changed. 2 shows the oxygen concentration inside the head space 11 on the side (side) and the oxygen concentration immediately after the gas replacement in the seamer gas supply unit 9. In Table 1, LN2
Represents a liquefied inert gas supply unit 7;
Medium, No. 4, Lm2 upstream 2.0m + LN
As shown in FIG. 1, “2 downstream 0.5 m” refers to the length of the transport path including the first and second inert gas replacement units A and B installed upstream of the liquefied inert gas supply unit 7. 2.0m,
This indicates that the length of the downstream side of the liquefied inert gas supply unit 7, that is, the third inert gas replacement unit C is 0.5 m. No. 2, No. 6, no. The same applies to each condition of No. 7. In addition, No. The expression “no sealing” in No. 6 indicates a condition when the ceiling 4a of the outer cover 4 is opened to release the semi-closed space state without setting the transport path to the semi-closed space state. In addition, No. 1, No. 3, No. “None” in 5 indicates a state in which the inert gas supply unit 6 and the sintering filter 12 are not provided and the inside of the transport path is simply placed in an inert gas atmosphere. The term “gas turret replacement” refers to the amount of the inert gas GN2 supplied to the head space 11 per unit time (per minute in this case) in the seamer gas supply unit 9. At this time, the can 2 is being conveyed at a speed of about 1.6 m / s (corresponding to 1000 cpm), and the sintered filter 12 is a 5 μm mesh. At this time, the oxygen concentration in the atmosphere is 20.9%.

No. 1 in Table 1. Under the condition of 3, the inert gas replacement unit is not particularly provided, and the can 2 after being transported along the transport path in a semi-enclosed space filled with the inert gas GN2.
Has an oxygen concentration of 14.6%,
It was 6.6% after gas replacement by the seamer gas supply unit 9. On the other hand, No. As shown in the condition of 4, the inert gas replacement section is installed 2 m upstream of the liquefied inert gas supply section 7 and the inert gas replacement section 0.5 m is installed downstream of the liquefied inert gas supply section 7. The oxygen concentration in the head space 11 is reduced to 6.3% only by passing through the transport path. Further, by further using the gas replacement by the turret 9, the oxygen concentration is reduced to 1.5%, and it can be seen that the gas replacement is sufficiently performed.

In addition, No. 2 and No. As can be seen from the comparison with No. 4, the oxygen concentration of the head space 11 after passing through the transport path is increased by setting the transport path of the inert gas replacement section upstream of the liquefied inert gas supply section 7 as long as possible. Reduced. No. 1 and No. No. 3 or No. 3 4 and No. As can be seen from the comparison with FIG. 7, by increasing the gas supply amount in the seamer gas supply unit 9, the oxygen concentration after replacement by the seamer gas supply unit 9 is reliably reduced. In addition, No. 6 and no. As can be seen from the comparison with FIG. 7, unless the transport path is maintained in a semi-closed space state, the oxygen concentration in the head space 11 of the can 2 cannot be sufficiently reduced by merely transporting the transport path.

If the air is not replaced to some extent (60 to 70%) by the inert gas replacement unit, even if the supply amount of the inert gas GN2 in the seamer gas supply unit 9 is increased, the oxygen concentration can be reduced to a desired oxygen concentration. Can not.

As described above, by continuously supplying the inert gas GN2 to the can 2 transported to the transport path in the semi-closed space state and simultaneously supplying the liquefied inert gas LN2 to the can 2, the can 2 is transported. Just passing the route, for example 60-
A gas replacement effect of about 70% can be obtained. Furthermore, by combining the supply of the inert gas GN2 from the seamer gas supply unit 9 immediately before the can lid is tightened, highly efficient gas replacement of 96% or more can be performed.

[0060]

The gas replacement apparatus and method for a can according to the present invention have the following effects. (1) The replacement gas is supplied from the seamer gas supply unit to the head space of the can immediately before the can lid is conveyed to the can seamer section and the can lid is fastened, and the replacement gas in the head space is transported on the upstream conveyor path. By installing a replacement gas supply unit provided at a plurality of locations along the transport path as a preliminary replacement means for continuously supplying a replacement gas from above the can, air in the head space of the can is conveyed to the conveyor. It is naturally replaced by the replacement gas just by being transported above. Therefore, the amount of oxygen in the head space is reduced, and deterioration of the contents due to oxygen is prevented. (2) By providing a seamer gas supply section for supplying a replacement gas to the head space immediately before the can lid is wound around the opening of the can in the can seamer section, the seamer gas is transported on the conveyor to some extent. The head space replaced with the replacement gas is sufficiently replaced with the replacement gas by the replacement gas supplied from the seamer gas supply unit. Therefore, the amount of oxygen in the head space is sufficiently reduced, and deterioration of the contents due to oxygen is prevented. (3) Since the transfer path is kept in a semi-closed space by the outer cover, gas replacement can be performed in a stable replacement gas atmosphere. (4) The replacement gas supplied from the replacement gas supply unit is:
The paper is supplied to the head space of the can which is conveyed after passing through a filter portion arranged above the can along the conveyance path. Therefore, the replacement gas that has passed through the filter section is uniformly supplied while diffusing into the transfer path maintained in the semi-enclosed space, and the replacement gas atmosphere inside the transfer path becomes uniform, thereby replacing the gas in the head space. It can be performed stably. (5) 0.5 m /
sec. By supplying to the head space of the can at the following flow rate, the air in the head space is replaced stably. In other words, when the replacement gas is supplied at a high flow rate, the replacement gas interferes with the airflow generated by the transported can, so that the replacement gas is not stably supplied into the head space. Therefore, the flow rate of the replacement gas is set to 0.5 m / s
ec. By supplying at the following low speed, gas replacement is performed stably. (6) Since a sintered filter formed of a mesh of 2 to 10 μm is used for the filter section, the replacement gas is sufficiently diffused by passing through the sintered filter and then supplied to the transport path. You. (7) A liquefaction / replacement gas supply unit is provided in the middle of the transfer path, and the liquefaction / replacement gas supply unit supplies the liquefaction / replacement gas to the head space, thereby vaporizing the liquefaction / replacement gas during transfer. Thereby, gas replacement of the head space can be performed more reliably. (8) By installing a narrowing plate formed at the lower end of the filter section so as to extend to the side wall of the can to be conveyed, the space between the upper end of the can and the filter section is reduced, and the Gas is supplied stably toward the head space. (9) A gas replacement method for a can for replacing air in a head space of a can filled with contents with a replacement gas, wherein a transport path maintained in a semi-enclosed space is directed toward a can seamer portion. To be continuously conveyed, to the head space of the can that contains the contents and is open at the top, while continuously supplying the replacement gas that has passed through the filter unit installed along the conveyance path, By gas replacement by a gas replacement method for a can, characterized in that a replacement gas or a liquefaction replacement gas is supplied to the headspace in the can seamer immediately before the can lid is fastened to the opening of the can. The gas can be replaced to some extent only by passing through the transport path, and the gas for replacement is supplied immediately before the can lid is wound tightly. The gas is sufficiently filled, the deterioration of the contents thereof in the reactor after sealing the can lid is wound up is prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of an embodiment of a gas replacement device for a can according to the present invention.

FIG. 2 is a side view illustrating a first replacement (inert) gas replacement section in FIG.

FIG. 3 is a cross-sectional view taken along line TT of FIG. 2, illustrating a vicinity of a replacement gas supply unit.

FIG. 4 is a view of the vicinity of a replacement gas curtain forming portion viewed from above.

FIG. 5 is a diagram illustrating an airflow near a can when the flow rate of the replacement gas supplied from the sintered filter is large.

FIG. 6 is a diagram illustrating an air flow near a can when the flow rate of the replacement gas supplied from the sintered filter is small.

FIG. 7 is a view for explaining the relationship between the flow rate of the supplied replacement gas and the oxygen concentration inside the headspace at each position on the transport path of the can.

FIG. 8 is a diagram illustrating a conventional gas replacement device for cans.

[Explanation of symbols]

Reference Signs List 1 inert gas replacement device (gas replacement device) 2 cans 2a contents 3 conveyor 4 outer cover 4a ceiling 5 inert gas curtain forming section (replacement gas curtain forming section) 6 inert gas supply section (replacement gas supply Part) 7 liquefied inert gas supply part (liquefaction replacement gas supply part) 8 can seamer part 9 seamer gas supply part 10 can opening part 11 head space 12 sintered filter 13 space part 14 filter support part 16 lifter 17 narrowing plate A first Inert gas replacement part B Second inert gas replacement part C Third inert gas replacement part GN2 Inert gas (replacement gas) LN2 Liquefied inert gas (liquefaction replacement gas)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumihiko Usui 1500 Suganuma, Koyama-cho, Sunto-gun, Shizuoka Prefecture F-term in the Aluminum Can Development Center of Mitsubishi Materials Corporation (Reference)

Claims (9)

[Claims] Claims 1. A can gas replacement device for replacing air in a head space of a can filled with contents with a replacement gas, comprising a continuous can containing contents and having an open top. A conveyor for transporting the conveyor to the can seamer portion; an outer cover for keeping a transport route of the conveyor in a semi-enclosed space immediately before the can seamer portion; and an outer cover provided at a plurality of locations along the transport route. A replacement gas supply unit for continuously supplying a replacement gas from above the can within the can, and the replacement disposed along the transport path between the replacement gas supply unit and the can A gas replacement device for a can, comprising: a filter section for lowering the flow rate of a working gas. 2. The gas replacement device for a can according to claim 1, wherein the replacement gas is provided to the head space immediately before a can lid is provided around the can opening provided in the can seamer portion. A gas replacement device for a can, comprising: 3. The gas replacement device for a can according to claim 1 or 2, wherein the replacement gas that has passed through the filter unit is placed above the can at a rate of 0.5 m / sec. A gas replacement device for cans, which is supplied at the following flow rate. 4. The gas replacement apparatus for a can according to claim 1, wherein the filter section has a diameter of 2 to 10 μm.
A gas filter for cans, characterized by being a sintered filter having a mesh. 5. The gas replacement device for a can according to claim 1, wherein a gas for liquefaction replacement is supplied to the head space in the middle of the transport path. A gas replacement device for cans, characterized in that a can is installed. 6. The gas replacement device for a can according to claim 1, wherein a narrowing plate formed at a lower end of the filter portion so as to extend to a side wall of the can to be conveyed. A gas replacement device for cans, characterized in that a can is installed. 7. The gas replacement device for a can according to claim 1, wherein the replacement gas is an inert gas or a carbon dioxide gas. 8. A gas replacement method for a can for replacing air in a head space of a can filled with contents with a replacement gas, wherein a transport path maintained in a semi-enclosed space is provided to a can seamer portion. To the headspace of the can that contains the contents and is open at the top, which is continuously conveyed toward, the replacement gas that has passed through the filter unit installed along the conveyance path is continuously supplied. A gas replacement method for a can, characterized in that a replacement gas or a liquefaction replacement gas is supplied to the head space in the can seamer portion immediately before a can lid is wound around an opening of the can. 9. The gas replacement method for a can according to claim 8, wherein the replacement gas is an inert gas or a carbon dioxide gas.