JPS63125118A - Gassing method of liquefied-gas sealed can - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention involves adding liquefied gas such as liquid nitrogen to a can filled with contents, replacing oxygen in the head space with an inert gas, and then closing the can. The present invention relates to a gashing method in the production of seamed cans, and particularly to a gashing method for cans filled with liquefied gas that enables gasssing while preventing liquefied gas added onto the contents from scattering.

Conventional technology Conventionally, in order to increase the axial strength of cans made of flexible materials, or to prevent deformation of the can due to negative pressure after cooling in a hot pack, the contents were placed on top of the can just before tightening the can lid. The internal pressure of the can is increased by dripping and sealing liquefied gas such as liquid nitrogen into the can.

On the other hand, in order to prevent the contents from being oxidized, altered, or denatured by the oxygen contained in the gas in the head space of a can, the gas in the head space is replaced with an inert gas such as nitrogen gas or carbon dioxide gas. Sealing and tightening is being carried out. and,
Sealing is also carried out by simultaneously filling in the liquefied gas and replacing with inert gas.

Conventionally, when seaming is performed by both charging liquefied gas and replacing inert gas, a liquefied gas storage tank is installed at the upper part of the conveyance path that transports the can from the filling machine to the seaming machine, just before the filling machine. From there, liquefied gas is continuously dripped into the cans that are continuously conveyed by a conveyor and added to the top of the contents. Thereafter, an inert gas such as nitrogen gas is sprayed into the head space of the can by an undercover gassing device in the seaming machine to replace oxygen in the head space with the inert gas and seam the can.

Problems to be Solved by the Invention Liquefied gas such as liquid nitrogen is at an extremely low temperature, and even when added to a can, it is extremely prone to scattering and is in an unstable state.

Therefore, if you perform gutsing using the conventional method described above.

Due to the inert gas blown into the head space during undercover gashing, the liquefied gas added to the contents will be scattered outside the can along with the gas in the head space, reducing the yield of inert gas inside the can. I wanted to get very angry. As a result, a predetermined can internal pressure could not be obtained, resulting in variations in internal pressure, which resulted in the production of defective cans.

The amount of inert gas blown out in a conventional undercover gassing device and the amount of oxygen in the head space of a can filled with contents have a relationship as shown by a solid curve A shown in the graph of FIG. On the other hand, the relationship between the amount of inert gas blown into the undercover gashing of a can to which liquefied gas has been added and the degree of variation in can internal pressure is as shown by solid curve B. As can be seen from this graph, the larger the amount of inert gas blown into the undercover gash, the smaller the amount of oxygen in the head space, but on the contrary, the degree of variation in the internal pressure of the can increases. Conventionally, the amount of oxygen in the headspace was reduced to 0.4
In order to achieve a resistance of /100 m1 or less, the amount of inert gas blown out in the undercover gashing needed to be 0.4 m3/min or more, and the degree of variation in the internal pressure of the can was large. Therefore, it has been difficult to reduce variations in can internal pressure and perform sufficient gashing using the conventional undercover gashing device.

The present invention was devised in view of the above-mentioned circumstances, and it is possible to perform sufficient gas packing without scattering the liquefied gas added to a can, and to obtain a predetermined internal pressure with less variation in can internal pressure. The object of the present invention is to provide a method for gassing cans filled with liquefied gas.

Means to solve problems A method for gassing a liquefied gas-filled can according to the present invention is as follows.

A gashing method for manufacturing cans in which a liquefied gas is added to a can filled with contents, oxygen in the head space is replaced with an inert gas, and the can lid is sealed. An inert gas discharge part that creates an inert gas atmosphere is provided on the conveyance path that conveys the material, and by passing the gas through the inert gas discharge part, the oxygen in the head space is inactivated before being supplied to the seaming machine. The above problem was solved by adopting a configuration characterized by replacing the gas with gas.

During operation of the working line, the lower active gas discharge section discharges the inert gas from the discharge port at such a low gas pressure that the inert gas naturally flows downward from the discharge port due to its own weight.

The filled can is continuously transported along a conveying path, and as it passes through an inert gas discharge section where an inert gas is flowing down, the oxygen in the head space of the can is removed by the inert gas flowing down. It is supplied to the seaming machine in a state in which gashing has been performed. At this time, since the flow pressure of the inert gas is extremely low, gassing is performed without causing the liquid nitrogen dropped inside the can to be scattered outside the can by the inert gas.

After that, the final gashing is performed by the undercover gashing device in the seaming machine if necessary, but preliminary gashing is performed before supplying to the first seaming device, so the undercover gashing device uses inert gas. The amount of gas blown out can be smaller than that of conventional models to achieve the desired gashing, and the liquefied gas added to the can is less likely to be scattered.

Variations in can internal pressure can be reduced.

Example Examples of the present invention will be described in detail below.

1 and 2 show an embodiment of an apparatus for carrying out the present invention.

In the figure, reference numeral 1 denotes a conveyance path that connects a content filling machine (not shown) and a seaming machine 2, and cans 3 filled with contents are pushed along the conveyance path by a pushing piece 5 attached to a chain 4. and supplied to the seaming section machine 2. 6 is the above can 3
This is the liquid nitrogen metering tank of the liquid nitrogen dripping device.

7 is its drip nozzle.

Reference numeral 10 denotes a pregassing device that constitutes an inert gas discharge section provided above the conveyance path on the upstream side of the liquid nitrogen dropping device. As shown in FIG. 2, the pregagging device has a frame body having a U-shaped cross section.

The two walls 11, 11' are attached to the machine frame by appropriate mounting means so as to hang down toward the can body of the can conveyed by the conveyor 1 and surround the can opening. A suitable number of nitrogen gas discharge ports 13 are formed on the top wall 12, and the discharge ports are connected to a nitrogen gas cylinder 15 via f14, so that nitrogen gas is discharged from the nitrogen gas discharge ports 13. It has become. In addition, in FIG. 2, 16 is a valve, 17 is a regulator, and 18 is an integrated flow meter.

Reference numeral 20 denotes a pregagging device configured similarly to the pregagging device 10 provided between the liquid nitrogen dripping device 6 and the seaming machine 2.

An embodiment of the gashing method of the present invention will be explained using the embodiment apparatus configured as described above. In the method of this embodiment, canned goods are manufactured by replacing oxygen in the head space of a can to which liquid nitrogen has been added with nitrogen gas.

This is an example of a so-called nitrogen-filled can in which pre-gagging is performed and then undercover gasssing is performed using a cinching machine.

Pregassing equipment during line operation [i'11O120 is
Nitrogen gas is discharged from the discharge port 13 from the liquid nitrogen gas cylinder 15 by setting the gas pressure to such a low level that it naturally flows downward from the discharge port due to its own weight by the regulator 17 . The can 3 filled with contents by a filling machine (not shown) is continuously conveyed by a pushing piece 5 on a conveying path 1 between the side walls 11 and 11' of the pregassing device where nitrogen gas is flowing down. pass through. At that time, the oxygen in the headspace of the can is replaced by the flowing nitrogen gas,
Gatsusing is carried out.

Thereafter, a predetermined amount of liquid nitrogen is added into the can by passing through the lower part of the liquefied gas dripping device where liquid nitrogen is continuously dripped. Furthermore, while the liquefied gas drips from the liquefied gas dripping device to the seaming device, preliminary gagging is performed in the same way as described above by the pregashing device 20 provided therebetween. At this time, since the flow pressure of the nitrogen gas is extremely low, gassing is performed without causing the liquid nitrogen dropped inside the can to scatter outside the can.

Thereafter, the final gashing is performed by the undercover gashing device in the first cinching machine, and the amount of nitrogen gas blown at this time is smaller than that of the conventional method, and the desired gashing can be performed.

According to the method of this embodiment as described above, the relationship between the amount of nitrogen gas blown into the undercover gashing by the cinching machine and the amount of oxygen in the can head space is expressed by the broken line curve C in FIG.
It is now shown in As is clear from the figure, the amount of oxygen in the head space can be reduced by a smaller amount of nitrogen gas compared to the conventional method, and 0.3 m'
It was possible to reduce the amount of oxygen in the head space to 0.4 resistance/low1 or less by blowing out nitrogen gas at a rate of 0.4/min. As a result, the amount of liquid nitrogen scattered is small, and the variation in internal pressure within each can is considerably reduced compared to conventional systems.

In the above embodiment, the pre-gagging device constituting the inert gas discharge section is installed immediately before and after the liquefied gas dropping device, and pre-gagging is performed both before and after dropping the liquefied gas. If the distance between the device and the tightening device is short, there is no need to perform pregagging between them.

On the other hand, if the distance between the liquefied gas dripping device and the seaming device is long, pregagging may be omitted between the filling machine and the liquefied gas dripping device. Furthermore, in the above embodiment, the undercover gashing is performed by the seaming device, but if the amount of oxygen in the can head space can be lowered below a predetermined value using only the inert gas discharge part, the undercover gashing is not necessarily performed. No need to sing.

Effects As described above, according to the method of the present invention, the oxygen in the can head space is replaced by the inert gas with an extremely low flow pressure before being supplied to the seaming device.
Sufficient gashing can be performed without scattering the liquid nitrogen added into the can, and a predetermined internal pressure can be obtained with little variation in the internal pressure of the can. Even when undercover gassing is performed using a seaming device, since pre-gagging is performed before supplying to the seaming device, the amount of inert gas blown out in one seaming device is smaller than that of conventional systems. Gushing can be performed, the liquefied gas added to each can is less likely to be scattered, and the variation in the internal pressure of each can is considerably reduced compared to the conventional one.

[Brief explanation of the drawing]

1 and 2 show an apparatus for carrying out the present invention, FIG. 1 is a schematic front sectional view thereof, FIG. 2 is a side sectional view of the main part thereof, and FIG. 3 is a nitrogen gas in undercover gashing. It is a graph showing the relationship between the amount of gas blown out, the amount of oxygen in the can head space, and the degree of variation in can internal pressure. 1: Can conveyance path 2: Sealing bag W1 3: Can 6: Liquefied gas dripping device 7: Liquefied gas dripping nozzle 10: Pregassing device 15: Inert gas cylinder patent applicant Toyo Seikan Co., Ltd. Applicant representative Patent attorney Sato Fumio (2 others)

Claims (1)

[Claims] A gassing method in can manufacturing in which a liquefied gas is added to a can filled with contents and the oxygen in the head space is replaced with an inert gas to seal the can lid. An inert gas discharge part that creates an inert gas atmosphere is provided on the conveyance path that conveys the material, and by passing the gas through the inert gas discharge part, the oxygen in the head space is inactivated before being supplied to the seaming machine. A method for gassing a can filled with liquefied gas, characterized by replacing the gas with gas.