JPH01226518A - Method for reducing residual oxygen in can in liquefied gas filling canning method - Google Patents

Abstract

PURPOSE:To reduce the amount of the residual oxygen in a can and effect an efficient gas replacement with a small loss of an inert gas, by performing a preliminary replacement by delivering an inert gas from immediately above the can with an upper pregassing unit and using an under cover gassing unit immediately before seaming. CONSTITUTION:An upper pregassing unit 10 in line operation is always feeding nitrogen gas from a nitrogen gas cylinder downwardly through a nozzle 13. During this time, the control of the gas amount is monitored by a manometer 18 or flow meter 17 mounted to a chamber. A can 4 filled with the liquid content is passed under liquefied gas feed device from which the liquefied is dropping continuously onto a conveying passage 1, whereby a predetermined amount of the liquefied nitrogen is added into the can. When the can with the liquefied nitrogen filled therein is passed under an upper pregassing unit, the nitrogen gas blown out of a nozzle is delivered into the can to replace the air in the space of the can head. The final gassing is effected by an under cover gassing unit in a seamer with a small a amount of gas.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for reducing residual oxygen in cans in the production of liquefied gas-filled cans using a combination of gas-filling and under-cover gasssing.

Conventional Technology When producing canned goods by filling can bodies made of flexible materials with foods and drinks, liquid nitrogen is filled to increase the internal pressure, and the contents are not oxidized, altered, or denatured. In order to prevent damage, the air in the head space is replaced with an inert gas such as nitrogen gas and the cans are sealed.

Conventionally, the above-mentioned liquefied gas filling and inert gas replacement were carried out by installing a liquefied gas flow device at the top of the conveyance path that conveys the cans from the filling machine to the seaming machine, and continuously conveying the cans to the cans that are continuously conveyed by a conveyor. This was done by dropping liquefied gas onto the can, and then using an undercover gassing unit inside the sear to blow an inert gas such as nitrogen gas into the head space of the can.

However, it has been difficult to sufficiently reduce the residual oxygen A3 in the head space using only undercover gashing. To this end, we have attempted to increase the gas replacement rate by blowing inert gas into the side of the can to perform preliminary gas replacement, or so-called pregassing, while the can is being transported before it enters the cinching machine after liquid nitrogen has been added. A new method has been proposed (Special Publication No. 15363 of 1983).

Problems to be Solved by the Invention In the conventional gashing method, whether it is undercover gashing or pre-gashing, nitrogen gas is blown from the side of the can, as shown in Figure 6. Dead volume that is difficult to reach Figure 4 is a graph comparing 250 g of liquid content into a 250 g can by hot-packing and performing conventional undercover gashing and gashing according to the method of the present invention described below. The diagram of UPGO, O shows the case of only conventional undercover gashing. As is clear from the figure, according to the conventional gassing method, as the amount of undercover gassing (i.e., the amount of nitrogen gas blown) is increased, the displacement effect (reduction in the amount of oxygen remaining in the can) gradually increases. But 0.3rr? ／It is saturated at around n resistance, and even if the amount of gassing is increased beyond that, the residual oxygen X is 0°4
It does not decrease below ml/can.

On the other hand, as shown in the diagram of UPGO,O in Fig. 5,
As the amount of gassing increases, the amount of liquid nitrogen floating on the contents increases, the variation in can internal pressure increases, and the occurrence of cans with poor internal pressure increases.

In other words, as is clear from both graphs, with conventional undercover gashing, even if the amount of gashing is increased, the amount of residual oxygen in the can can only be reduced to close to 0.411Il/can; There is a problem in that increasing the effectiveness increases the variation in can internal pressure, resulting in a large number of cans with poor internal pressure. .

In addition, although the proposed method of using pregugging and undercover together can increase the gas replacement rate compared to the undercover gassing alone, it is still not sufficient, and there is a large loss of inert gas. There is a problem with this.

The present invention has been devised in view of the above-mentioned circumstances, and is an ff that performs filling with liquefied gas such as liquid nitrogen and replacing with inert gas.
In the production of J-packed cans, there is no large variation in the internal pressure of the can, and the residual oxygen in the can can be reduced.There is no residual oxygen in the can for liquefied gas-filled cans. The purpose is to provide a method for reducing oxygen.

Means for Solving the Problems The inventor of the present invention has conducted various studies to solve the above problems, and as a result, has developed a method for replacing conventional pregagging.

By blowing inert gas directly into the opening of the can filled with liquefied gas such as liquid nitrogen and continuously transported to the seamer, a high replacement rate is achieved without creating dead volume inside the can. Moreover, contrary to what was previously thought, the liquefied gas filled inside the can scatters less outside the can, and the variation in the internal pressure of the can is also smaller than before, and the present invention was achieved. It is something.

That is, the method for reducing the residual oxygen in the can in the liquefied gas-filled can I2 production of the present invention is to reduce the amount of oxygen remaining in the can on the downstream side of the liquefied gas flow down device installed on the conveyance path that conveys the can from the filling machine to the seaming machine. An upper pre-gagging unit with a nozzle is placed on the bottom of the chamber, and the upper pre-gagging unit directs the inert gas directly above the can into which liquefied gas is added and directed toward the opening of the can, which is conveyed to the seaming machine. The air inside the can head space is preliminarily replaced with an inert gas by blowing into the can head space, and then the can tightening machine tightens the can. The above problem is solved by adopting the configuration.

With upper pre-gagging, nitrogen gas is blown into the can from directly above, ensuring that it is blown into the can, eliminating the dead volume that occurs with conventional pre-gutting from the side, and evenly distributing the air inside the can. It can be replaced with nitrogen gas, and a high replacement effect can be obtained by pregassing.

As a result, the amount of undercover gashing in the winding machine can be reduced to about half of the conventional amount, and as a result, the amount of liquefied gas filled in the can can be reduced to the outside of the can. Variations in internal pressure can also be dramatically reduced. According to the method of the present invention, the residual amount of oxygen in the can can be reduced to 0, 4, which was difficult with conventional undercover gasssing.
It is possible to reduce F to below ml/can (residual oxygen amount that can be practically ignored even in contents that are extremely averse to oxidation such as edible oil, fruit juice drinks, sports drinks, etc.), and it also eliminates variations in can internal pressure. The ratio can be reduced to about 1 defective can due to insufficient internal pressure for every 400,000 cans.

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

1 and 3 show an embodiment of an apparatus for carrying out the invention.

In the figure, 1 indicates a content filling machine 2 and a seaming machine 3 (not shown).
Cans 4 filled with contents are supplied to the seaming machine 3 at predetermined intervals by a pushing piece attached to a chain on the side conveying path. Reference numeral 5 denotes a liquid nitrogen flow down device provided on the conveyance path, which continuously supplies liquid nitrogen from a dripping nozzle provided at the bottom of the liquid nitrogen storage tank.
Add liquid nitrogen to the headspace of the can being conveyed below. The seaming machine 3 has a cover feed turret 6 having an undercover gushing unit, a seaming turret 7, and a discharge turret 8. Reference numeral 10 denotes an upper pregassing unit provided above the conveyance path downstream of the liquid nitrogen dripping device, and as shown in FIGS. 2 and 3, the unit has a width of approximately 1/2 of the can diameter. It is formed into a box shape, and a nozzle 13 is provided on the lower surface of the chamber 11.

The upper surface is sealed and communicated via a replacement gas supply pipe 14 to a replacement gas source 15 such as a nitrogen gas cylinder.

The displacement gas supplied from the displacement gas source has its gas pressure controlled by a pressure reducing valve 16, or its flow rate is controlled by a throttle valve 17 having a flow meter, so that a predetermined amount of gas is supplied into the chamber. It has become. 18 is a pressure gauge, 1
9 is a stop valve.

The shape of the nozzle 13 provided on the lower surface of the chamber 11 is as follows:
For example, as shown in FIG. 3, a honeycomb nozzle 21 having a plurality of small holes, a slit nozzle 22 having a slit orthogonal to the conveyance path, and a round hole with one round hole formed in the center. An appropriately shaped nozzle such as a shaped nozzle 23 can be adopted.

While the line is in operation, the upper pregassing unit 10
Nitrogen gas supplied from a nitrogen gas cylinder is constantly blown downward from the nozzle 13. At that time, the gas amount is controlled by the pressure gauge 1 attached to the chamber.
8. Alternatively, the flow meter 17 is monitored and the pressure reducing valve 16 or the throttle valve 17 is used. The can 4 filled with liquid is transported through the conveyance path 1
A predetermined amount of liquid nitrogen is added to one can by passing through the lower part of a liquefied gas flow device on which liquid nitrogen is continuously dripped. When liquid nitrogen passes through the lower part of the upper pre-gassing after being filled with liquid nitrogen, the nitrogen gas blown from the nozzle of the upper pre-gassing is blown into the can.
Replace the air in the can headspace with nitrogen gas. After that, the final gashing is performed by the undercover gashing unit in the seaming machine, and the amount of nitrogen gas blown at this time is smaller than that of conventional gashing, and the desired gashing can be performed.

Using the above-mentioned device, the amount of undercover gutting is set to 0.15.0.20.0.25. and 0, 3
0 +n''/sin, the chamber internal pressure of the upper pregugging unit with the honeycomb-shaped nozzle is 0.0 (i.e., no upper pregugging), 0.1, o, 2°, and 0, respectively. 3 kg/
The amount of residual oxygen in the can was measured when upper pregagging was performed instead of using the method J.

The measurement results are shown in the graph of FIG. As is clear from the graph, one example of the present invention, for example, O,1k
When upper pre-gugging is performed at g/ad, the amount of undercover gashing is 0.17 rrr/win, and the residual oxygen amount can be reduced to 0.4 ml/can, and the amount of undercover gashing is 0°. 3m/si
When increasing to n, the residual oxygen amount becomes 0.327+sl/
I was able to lower it to ca. On the other hand, in the case of only undercover ganossing without upper pregagging, as mentioned above, the residual oxygen amount is set to 0,
To reduce to 4 ml/can, 0,3 rn
An undercover gutting amount of 1/111 inch or more was required.

Furthermore, when we measured the degree of variation in the internal pressure of the canned food obtained in this manner for each of 20 cans that had been replaced with gas under the rude conditions, we obtained the results shown in the graph of Figure 5. Ta. As is clear from the graph, for example, when only undercover gasssing is performed without performing upper pregugging, the variation in the internal pressure of the can is the standard deviation when the undercover gassing amount is 0.10 I/l σ is O9156 kg/C5d, and the standard deviation increases as the undercover gashing amount increases. For example, if the residual amount of oxygen in the can is 0,4 m
When lowering to 1/can, undercover gashing alone will result in 0,3 rn' as shown in Figure 4.
A flow rate of /m, in was required, and the standard deviation α at this time was 0°22 kg/d. If this is combined with the upper pre-gugging of the present invention, upper pre-gagging Q, 1 kk Ta. That is, the amount of residual oxygen in the can is 0, 4
When the gas is replaced until it drops to ml/can, there is a standard variation in the can internal pressure between the conventional undercover gassing alone and the case where upper pre gassing is used in combination as in the present invention. There was a difference of 5/100 in deviation.

The effect of this standard deviation difference of 5/100 can be seen in Table 1 when upper pregugging and undercover gushing are used together, assuming that the average can internal pressure is normally distributed on a production line that produces 400,000 cans per day. In addition, when only undercover gutting is performed, the results are as shown in Table 2. As can be seen from the table, the internal pressure of one can is 1.01. k,
, /- or less, only one can is generated when both methods are used as in this embodiment, whereas 117 cans are generated when only undercover gashing is used.

As shown in Effect 2, according to the method of the present invention, in the production of canned goods in which filling with liquefied gas such as liquid nitrogen and replacing with inert gas, nitrogen gas is blown from the bottom by upper pregassing. Therefore, a high displacement effect can be obtained by pre-gagging without the generation of dead volume, and the amount of residual oxygen in the can can be reduced significantly. Since the amount of liquefied gas scattered outside the can can be reduced dramatically, the variation in the internal pressure of the can can also be dramatically reduced.

[Brief explanation of the drawing]

1 to 3 show an apparatus for carrying out the present invention, FIG. 1 is a plan view thereof, FIG. 2 is a side view of the upper pregagging unit, and FIG. 3 is a side view of the upper pregagging unit. Fig. 4 is a graph showing the relationship between the amount of gashing and the amount of oxygen remaining in the can, and Fig. 5 is a graph showing the relationship between the amount of gassing and the standard deviation of the internal pressure in the can.
FIG. 6 is a side view showing the conventional gashing method. 1: Can transport path 2: Filling machine 3: Sealing machine 4: Can
5: Liquid nitrogen flow device 10: Upper pregassing unit t-11: Chamber 1-3: Nozzle
15: Replacement gas source 16: Pressure reducing valve 17: Throttle valve 2
1: Honeycomb-shaped nozzle 22 Nislit-shaped nozzle 23
: Round hole nozzle patent applicant Toyo Seikan Co., Ltd. 2 Jyutori Figure 1 Figure 3 (a), (b) ('
c) Ga, // Gu weight m3/min Figure 4

Claims (1)

[Claims] This is a method for reducing residual oxygen in cans in the production of liquefied gas-filled cans, in which liquefied gas is added to cans filled with contents and the can lids are sealed. An upper pre-gassing unit having a nozzle on the bottom of the chamber is arranged above the conveyance path on the downstream side of the liquefied gas flow device installed on the side, and the upper pre-gassing unit is filled with liquefied gas and the seaming machine Inert gas is blown into the opening of the can from directly above the can to preliminarily replace the air in the can head space with inert gas, and then undercover gassing is performed just before the can seaming machine tightens the can. A method for reducing residual oxygen in cans in the production of liquefied gas-filled cans, which is characterized by performing undercover gassing using a unit.