CA1215950A - Plural anti-splash injection streams in liquid gas food sealing systems - Google Patents
Plural anti-splash injection streams in liquid gas food sealing systemsInfo
- Publication number
- CA1215950A CA1215950A CA000426380A CA426380A CA1215950A CA 1215950 A CA1215950 A CA 1215950A CA 000426380 A CA000426380 A CA 000426380A CA 426380 A CA426380 A CA 426380A CA 1215950 A CA1215950 A CA 1215950A
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- containers
- liquefied gas
- released
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Abstract
ABSTRACT OF THE DISCLOSURE
A method of manufacturing pressurized sealed containered food is disclosed, in which a pre-determined quantity of liquefied nitrogen is charged through two or more liquefied nitrogen outlets into a succession of individual containers which have already a predetermined quantity of food including liquid content are successively travelling upright with the top end open at a constant speed, and each container is subsequently sealed with a lid.
A method of manufacturing pressurized sealed containered food is disclosed, in which a pre-determined quantity of liquefied nitrogen is charged through two or more liquefied nitrogen outlets into a succession of individual containers which have already a predetermined quantity of food including liquid content are successively travelling upright with the top end open at a constant speed, and each container is subsequently sealed with a lid.
Description
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The present invention relates -to a method o~ manu-fac-turing pressurized, sealed containered food by charging a predetermined quanti-ty of liquefied nitrogen through a lique-fied nitrogen outlet into individual containers, which are s-till open at the -top and have already a predetermined quanti-ty of food including liquid content while the containers are successively travelling at a constant speed and then sealing each con~ainer with a lid.
By the term "containered food" is meant canned food, bottled food or the like, and by the term "pres~urized, sealed contain-ered food" is meant for example, a canned food containing food (e.g., solid food plus syrup) together with a low-temperature liquefied gas.
A method of charging a predetermined quantity of a low-temperature liquefied gas is sought in various industrial fields. Particularly, a method of charging an inert low-temperature liquefied gas is desired not for packing frothable liquid food containing CO2 gas, e.g., beer, in containers but for packing non-frothable liquid food, (e.g., fruits in syrup;
juice drinks; orange drinks containing orange sacs; and coffee drinks) by means of, for example, hot filling process.
With a hot filled product in a can or the like, the can becomes depressed or convex when a negative pressure is generated as the temperature of the content falls after its sealing with a lid. Accordingly, the thickness of the can body is made sufficiently large so that it will not become de-pressed even when a negative pressure is generated. Recently, however in order to use cans having a thin body, i-t has been proposed to charge a predetermined quantity of an inert gas in the liquid state (which does not change the taste of the contents, such as liquid nitrogen) into the can containing a non-frothable drink filled while it is hot, so that pressure ~ . . .
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in the can is higher than atmospheric pressure after the can has been sealed and the content has been cooled down (at which time the liquefied gas is vaporized).
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In the method of manufacturing ga~-sealed con~ainered food, in which an inert low-temperature liquefied gas (herein-after referred to merely as low-temperature liquefied gas) is continuously charged into containers at high speed, there are problems.
In this method~ a low-temperature liquefied gas is charged into containers while the containers are being moved at high speed. Therefore, the charged low-temperature liquefied gas is partly spattered to the outside of the containers and also partly vaporized to escape from the containers. Where the low-temperature liquefied gas is continuously released, it also falls into space between containers. With this method, therefore, considerable loss of low-temperature liquefied gas results. In addition, the quantity of low-temperature lique-fied gas that is retàined in individual containers fluctuates greatly.
To be more specific, the low-temperature liquefied gas has very low boiling point. (For example, liquid nitrogen has a boiling point of approximately -196C, and liquid argon has a boiling point of -186C at the atmospheric pressure). While the low-temperature liquefied gas as released from an outlet flows toward the surface of the liquid in the container, the low-temperature liquefied gas is partly vaporized due to exposure to the surrounding atmosphere. It is also partly vaporized when it comes into contact with the liquid content. The re-sultant vaporized gas escapes to the outside of the container.
Further, when the low-temperature liquefied gas strikes the surface of the content in the can, the low-temperature lique-fied gas is partly spattered to the outside thereof by the ~Z~LS9~) striking impact. Still further, it is partly spattered by a blow~out action of sudden vaporization just when it reaches surface on the content. For the above reasons, a considerable amount of low-temperature liquefied gas is lost.
Moreover, the quantity of low-temperature liquefied gas (or evaporated gas) that remains in the container after the sealing thereof with a lid fluctuates greatly among indi-vidual containers.
Generally, volume of the low-temperature liquefied gas which is vaporized immediately after its release from the outlet and until it comes into contact with liquid content in the container is in proportion to the area of exposed surface of the released low-temperature liquefied gas.
From this standpoint, i.e., from the standpoint of reduction of the vaporization it has been considered to date that it is the best method to let a predetermined quantity of low-temperature liquefied gas be released from a single nozzle having a single outlet.
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With this method of manufacture of~ga~-sealed con-tainered food, however, a great deal of low-temperature lique-fied gas is still lost, and quantity of the gas retained in the container fluctuates greatly among individual containers.
Therefore, this method has not been commercially used. To overcome the above disadvantage, there has been proposed a method, in which the velocity at which the low-temperature liquefied gas reaches the content in the can, does not exceed 350 cm/sec. (as disclosed in Japanese Patent Open Publication No. 161915/81~.
~ccording to this proposed method, the loss of low-temperature liquefied gas can be reduced to some extent. How-ever, the loss is still considerable, and also the quantity of low-temperature liquefied gas (vaporized gas) retained, in ,- 12~5g~
the container fluctuates greatly.
The present invention provides a method of manu~actur-ing pressurized, sealed containered food, which can reduce -the fluctuations of the quali-ty of low-temperature liquefied gas retained in individual containers to a small range.
The present invention also provides a method of manufacturing pressurized, sealed containered food, which can reduce -the loss of low-temperature liquefied gas released from an outlet and charged into containers.
According to one aspect thereof the invention provides a method of manufacturing pressurized, nitrogen gas-sealed containered food, the internal pressure of the container after the sealing thereof being greater than the atmospheric pressure, by charging liquefied nitrogen in a predetermined quantity continuously through an outlet for releasing said liquefied nitrogen into each of said containers, said containers successively travelling at a constant speed, each having a predetermined quantity of food including liquid content and being open at the circular top end, said liquefied nitrogen making the internal pressure of the containers after the sealing thereof greater than the atmospheric pressure, and subsequently sealing each of said containers with a lid, wherein said liquefied nitrogen is released continuously onto the content liquid surface from a plurality of outlets arranged in a row extending substantially parallel to the direction of travel of the containers and being above the diametrical line of said circular top end or above near said diametrical line, thereby allowing the liquefied nitrogen released from each of the outlets to pass above substantially said diametrical line of the circular top end, and further allowing the liquefied nitrogen released from each of the ou-tlets in one row to fall, one after another, onto substantially the same position on the content liquid surface.
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In a particular embodiment of the present invention the liquefied nitrogen is released from a plurality of outlets arranged in a plurality of rows extending substan-tially parallel to -the direction o~ travel of the containers.
~ he present invention will be further illustrated, by way of the accompanying drawings, in which:-Fig. 1 is a fraymentary sectional view showing oneembodiment of apparatus for carrying out the method according to the invention;
E~ig. 2 is a bottom view showing a nozzle of the apparatus shown in Fig. l;
Fig.s 3 and 4 are bottom views showing other examples of the nozzle in other embodiments of apparatus for carrying out the method according to the invention;
Fig. 5 is a framentary sectional view showing another embodiment of apparatus for carrying out the method according to the invention; and Fig. 6 is a bottom view showing a nozzle in an appara-tus used for experiments carried out for the purpose of compar-ing the results obtained according to the invention.
In the Figures, arrows indicate the direction of travelof containers.
Ihe inventors have conducted extensive experiments and found that when releasing low-temperature liquefied gas through the outlet of a nozzle into containers having liquid content while the containers are being moved, the spat-tering and rapid or drastic vaporization of the released low-temperature liquefied gas due to collision thereof with liquid surface of content increase in proportion to the intensity of ~ ~L2~S9S~
collision.
The inventors have also found that the release of the low-temperature liquefied gas through a plurality of outlets will reduce the intensity of collision of the liquefied gas with the content liquid surface and suppress the spattering and drastic vaporization of the liquefied gas in a much more effective manner than the release through a single outlet, provided that the quantity of low-temperature liquefied gas to be released is the same.
As mentioned earlier, the vaporization of the lique-fied gas released from the outlet until it reaches the content liquid surface in the can is proportional to the area of ex-posed surface of the liquefied gas.
That is, when a predetermined amount of the lique-fied gas is charged into the can from a plurality of outlets and a single outlet respectively, the area of exposed surface of the liquefied gas released from a plurality of outlets is essentially larger than that from the single outlet, so that the plurality of outlets allow greater vaporization of the liquefied gas than the single outlet does This means that in order to minimize the possible disadvantage of a method using a plurality of outlets as above the outlets must be set as close to the top of the container as possible. Desirably, this distance is set to be less than approximately 35 mm, or more preferably, less than 10 mm. By this setting of the outlets the intensity of collision noted earlier is reduced to such extent that velocity of the released liquefied gas suppresses the spattering and the like, whereby the possible disadvantage of a method of using a plurality of outlets can be successfully overcome.
The first aspect of the present invention is based on the above findings.
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The inventors have further found as a result of ex-periments if the pluralit~ of outlets are arranged in a row extending substantially parallel to the direction of travel of containers having the liquid content which are travelling with their top end open, the spatteriny and sudden vaporization of the low-temperature liquefied at the time of the collision thereof with the content liquid surface in the container can be reduced as compared with the case of other arrangements.
In addition, reduction of fluctuations of the pressure in the container after the sealing thereof can also be obtained.
The second aspect of the present invention is based on the above findings.
Reasons that the arrangement of the outlets in a row extending substantially parallel to the direction of pro-gress of the successively travelling containers having liquid content with its top open can reduce the spattering~ vaporiza-tion of the low-temperature liquefied gas and fluctuations of the inner pressure of the container after the sealing thereof have not been clearly elucidated. However, conceivable reasons are as follows. With the arrangement noted above, the low-temperature liquefied gas, which is released from the respec-tive outlets, can successively fall into substantially the same position of the content liquid surface at a very short time interval. To be more specific, the low-temperature lique-fied gas released from the first outlet in the row, the outlet on the left hand end of the row in Fig. 1, in the direction of travel of the containers falls onto the content liquid surface at a position thereof. Then the liquefied gas released from the second outlet also falls onto substantially the same posi-tion as that of the above content liquid surface. Likewise,the liquefied gas released from the third, fourth and so forth outlets successively falls onto substantially the same position -- lZ~59~
as above. The low-temperature liquefied gas released from the second outlet and thereafter thus falls on the liquefied gas which has already been charged into the container. It is thought that this has an effect of reducing the vaporization of the low-temperature liquefied gas at the time of collision thereof with the content li~uid surface and also reducing the spattering of the liquefied gas caused by the sudden vaporiza-tion of the liquefied gas.
Further, where the container to which the low-temper-ature liquefied gas is to be charged has a cylindrical shapelike a can or has a circular or oval open top end, the outlets may be arranged along a line which is substantially parallel to the direction of travel of the containers and also substan-tially parallel to the diametrical line of the container. In this case, even if the low-temperature liquefied gas is re-leased continuously, it substantially falls onto the diamet-rical line, of the container, where the spaces between con-tainers are naturally kept to a minimum. Thus, the quantity of the low-temperature liquefied gas falling into the spaces be-tween adjacent containers can be reduced.
An embodiment of the invention will now be described with reference to the drawings.
A low-temperature liquefied gas storage tank 1 has a double-wall heat-insulating structure having inner and outer walls 2 and 3. A space between the walls 2 and 3 is evacuated.
The bottom of the storage tank 1 has a nozzle 4, through which a low-temperature liquefied gas is released down.
The nozzle 4 has outlets 5. In the example shown in Figs. 1 and 2, five outlets are provided in a row along a straight line.
Reference numeral 6 designates containers into which a liquid content has already been filled. In the examples, two-piece cans are shown. These containers 6 are supported at S95~
their body portion by respective pawl members 7 attached at a uniform interval to an endless chain (not shown) which travels at a constant speed.
Reference numeral 8 designates a guide rail which restricts mo~ement of the containers in directions perpendicu-lar to the direction of their travel. Reference numeral 9 designates a table, on which the containers are slidably moved.
The individual outlets 5 are preferably arranged such that the center of the open top end of the containers 6 moves past these outlets 5. (For example, in case of contain-ers having a circular open top end, the diametrical line through the container parallel with the direction of travel thereof is preferably vertically overlapped by the row of the outlets 5.
The surface of the low-temperature liquefied gas in the storage tank 1 is subjected to an atmospheric pressure, and the level of the liquefied gas is controlled substantially constantly by a level control sensor and an electromagnetic valve (these being not shown). Thus the total amount of the low-temperature liquefied gas released from the outlets 5 per unit time is held substantially constant.
With this apparatus, the low-temperature liquefied gas can be released at a substantially constant rate (ml/sec.).
Accordingly, a constant quantity of low-temperature liquefied gas can be charged into the individual containers if the con-tainers with the top ends open are moved at a constant speed right under the outlets releasing the liquefied gas continu-ous ly .
As soon as the low-temperature liquefied gas is charged into each container, the container is immediately sealed by a well-known method and apparatus to prevent the charged liquefied gas from bein~ dispersed to atmosphere by its vaporization and thus a constant gas pressure in the _ g _ .59~
container is maintained.
Example 1 Cans having a diameter of approximately 52.6 mm (or commonly termed 202 diameter), a height of approximately 132 mm and a capacity of 250 ml were used. A juice drink containing 10% of orange juice was used as the liquid content. The juice drink is poured at a temperature of 95C into each can to leave a predetermined head space. The individual cans thus filled with the juice drink were immediately moved at a rate of 450 cans per minute (with adjacent cans spaced apart by approximately 5 cm) past a position right under liquid nitro-gen releasing outlets. Six liquid nitrogen releasing noz71es having different outlet arrangements A to F as listed in Table 1 below were used (the arrangement A being a contrast). The liquid nitrogen continuously released from the nozzle is charged into the moving cans. Each can was then sealed immedi-ately with an easy-open lid by the use of a sealing machine.
Approximately 1.8 seconds was taken to start sealing of the can since it had just past under the outlets.
The distance from the liquid surface of the liquid nitrogen storage tank to the bottom end of the outlet was con-trolled to approximately 110 mm. The distance from the bottom end of the outlet to the top end of each can moving under the outlet was set to 5 mm (the head space of each can being set to 12 mm). Under the conditions described above, the flow rate of liquid nitrogen at the points of release from outlets was measured. The results are listed in Table 1.
Table 1 = _ A B C D E F
Number of outlets 1 2 3 5 8 12 Outlet diameter (mm) 1.7 1.2 1.0 0.8 0.6 0.5 Flow rate tml~sec.) 2.54 2.56 2.62 2.56 2.58 2.55 - ~.2~LS~
In the outlet arrangements B, C and D, the outlets are arranged in a row extending parallel to the direction of travel of cans. In the arrangement E, the outlets are arrang-ed in two rows each having four outlets, and in the arrange-ment F outlets are arranged in three rows each having four outlets, extending parallel to the direction of travel of cans.
After the cans having the liquid content and liquid nitrogen therein were sealed, they wexe cooled down to room temperature. Then, the inner pressure in 25 cans tested by means of the outlet arrangements A to F were measured. The results are shown in Table 2.
Table 2 (n=2~) A B C D E F
pressure (kg/cm2) 1.21 1.31 1.47 1.69 1.55 1.68 Fluctuation 0.5- 0.7- 1.1- 1.5- 1.5 ~ 1.5-range kg/cm2~ 1.6 1.7 1.8 1.9 1.9 1.9 _ deviation (kg/cm2) 0.26 0.20 0.17 o.ll 0.12 0.11 It will be readily appreciated from Table ~ that higher inner pressure can be obtained with two or more outlets than with a single outlet. This means that a greater quantity of liquid nitrogen remains in the can in the case where two or more outlets are provided.
In addition, in the case o using two or more out-lets, it is shown that the inner pressure fluctuation becomes smaller, which generally means more stable quality of the con-tainered food.
This favorable result is appreciated to be attribut~
able to the effect of the provision of a plurality of outlets as all outlet arrangements in the examples are set to the same conditions in terms of amount and flow rate of released liquid nitro~en ( the same level of liquid nitxogen under atmospheric ` ~ 12159S~
pressure and the same distance from the outlets to the top end of the cans for all arrangements).
As has been shown, by means of provision of two or more low-temperature liquefied gas outlets a larger amount of the charged low-temperature liquefied gas is retained in the can ~the retained liquefied gas is soon vaporized after the sealing of the can) as compared with the provision of a single outlet in accordance with the prior art.
The desired amount of liquefied gas thus can be re-tained in the can with a lesser amount of the low-temperature liquefied gas to be released.
Increased quantity of the liquefied gas to be retain-ed in the can or decreased lose of released liquefied gas caus-ed by spattering, vaporization etc. means that it is possible to narrow the range of fluctuations of the amount of the lique-fied gas to be retained in the sealed can, which gives an effect of reducing possibility of defects of canned food such as swelling of the can lid due to excess liquefied gas or depres-sion of the can body due to insufficient liquefied gas sealed in the can.
The plural number of outlets provided in this inven-tion may be N in a single nozzle or N/M in a plural number tM) of nozzles. It is further possible to provide different num-bers of outlets in respective M nozzles. Here M and N are re-spectively a naturalnumber which is more than 2.
Experiment Cans in 202 diameter having a capacity of 250 ml identical with the can in Example 1, were used. Water at 93C
was poured into each can to leave a head space of approximately 13 mm. The individual cans were then conveyed immediately at a rate of 1,200 cans per minute under liquid nitrogen outlets and then each sealed with an easy-open lid. Approximately ~z~s~
0.5 seconds was taken to start sealing of the can since it hadjust past under the outlets.
The li~uid nitrogen releasin~ apparatus used, in this experiment has two nozzles each having two rows of five outlets of 0.5 mm in diameter arranced along a line extending substantiall~ parallel to the direction of travel of cans. The total releasing amount was set to 5.6 ml/sec. The experiment was carried out by changing the distance between the bottom of the rows of outlets and the can top end to 1, 5, 10, 25, 35 and 50 mm respectively, and the average inner pressure and pres-sure ~luctuations in the cans were measured. The results are shown in Table 3 below.
Table 3 Distance from Average inner Fluctuation Standard outlet end to pressure ~ range of inner deviation2 can top end (kg/cm ) pressure ~ (kg/cm ) (mm) (kg/cm ) 1 1.55 1.4 -1.7 O.Og 1.53 1.3,-1.8 0.11 1.47 1.2 ~ 1.7 0.14 1.43 1.1~ 1.6 0.15 1.41 1.0~1.7 0.18 Average value Average value was was not calcu- not calculated lated because because the maxi-paneling occur- mum was 1.6 while ed in two cans. the minimum was minus.
* Measurement was done for 15 cans for each distance.
It will be appreciated from the results of the experi-ment that when the low-temperature liquefied gas is charged into a can already filled with a liquid content leaving an ordinary head space, it is necessary to set the distance from the bottom of the outlet to the can top end to 35 mm or below, preferably 10 mm or below in order to allow smaller loss of 5~
the low-temperature liquefied gas and fluctuations of the inner pressure in the can.
Example 2 This example pertains to the second aspect of the invention mentioned above.
In this example, tin plate DI cans of approximately 52.6 mm diameter (202 diameter), approximately 132 mm of height with 250 ml capacity were used.
Approximately 240 g (more specifically 240 - 1 g) of water at 90C was poured into the DI cans at a rate of 450 cans per minute. Liquid nitrogen was then charged into these cans while they were being moved at the same speed of 450 cans per minute under various arrangements of the liquid nitrogen nozzle units as shown below, and immediately thereafter the cans were sealed each with an easy-open lid using a sealing machine.
Conditions of Experiment Quantity of liquid nitrogen charged - approximately 0.22 ml per can Time taken from the completion of charging of li~uid nitrogen to the start of sealing - 1.8 seconds Distance from the bottom of the outlet to the top of S ~n ,n the can flange (vertical distance) - approximatelyq~
Level of liquid nitrogen in the storage tank - approx-imately 140 mm Nozzle unit specifications (i~e., number and diameter of outlets), outlet pitch (center-to-center distance between adjacent outlets) - as listed in Table 4 (in the Examples G, H, I and J, the outlets were 5 in number and 0.8 n~ in diameter and spaced apart at a pitch of 2.5 mm, while in Example K the outlets were 12 in number, 0.52 mm in diameter and spaced apart at a pitch of 2.02 mm.) ~2~S~O
In the nozzle unit G the outlet row was arranyed to substanti~lly vertically overlap the diametrical line of the open can top parallel to the direction of travel of cans.
Result of Ex~riment Table 4 shows the measurements of average inner pres-sure in the can, ~luctuation range thereof and standard devia-tion.
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It will be appreciated from Table 4 that with the same number of outlets texamples G, H, I and J) the highest average inner pressure (1.82) in the cans and the smallest inner pres-sure fluctuation range (0.5 or the balance of max. 2.~ and min.
1.5) can be obtained by means of the outlet arrangement in a row parallel to the direction of travel of cans (example G).
The closer to a line parallel to the direction of travel of cans, the row of outlets are arranged, the higher is the average inner pressure in the cans and the smaller is the inner pressure fluctuation range.
Since the total rate of release of liquid nitrogen was the same with all the nozzle units used, it is appreciated that the higher average inner pressure in the can means the lesser loss of li~uid nitrogen released from the outlets.
One of the reasons for the lesser loss is thought to be attributable to the reduction of spattering and sudden vap-orization of the liquid nitrogen released from .he outlets at the time of the collision of the released liquefied gas with the surface of the content in the can. Another conceivable reason is that the released liquefied gas which falls into space between adjacent can is decreased as the row of outlets runs closer to a line parallel to the direction of the travel of cans as the cans are cylindrical and the farther the row o outlets is set off the diametrical line of the open top end of the can parallel to the direction of travel of cans, the great-er is the quantity of released liquefied gas directed to the outside of the can. Further, it will be appreciated from the comparison of the results in the examples K and G that lesser loss o~ liquid nitrogen and inner pressure fluctuation range can be obtained by reducing the diameter of each outlet and the rate of release per outlet while maintaining the same total release rate.
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(Outlets in Fig. 3 are shown in the same size as those in Fig. 2 for easy depiction.) This is thought to be attributable to the reduction of the inte~sity of collision of the liquid nitrogen released from each outlet with the surface of the liquid content in the can, and hence the reduction of the loss or spattering of liquid nitrogen toward the outside of the can.
In the case of arxangement K, it is desirable from the standpoint of reducing the released liquid nitrogen which falls into space between the cans that the nozzle 4 is so positioned with respect to the cans 6 being conveyed that the liquid nitrogen released from the respective rows of outlets falls onto opposite sides of the diametrical line of the circle of the open top end of the cans 6.
Fig. 4 is a bottom view of another nozzle which is used for carrying out the method according to the invention.
This nozzle has a total of eighteen outlets 5 arranged in three rows each having six outlets and extending parallel to the di-rection of travel of containers as shown by arrows. Outlets in Fig. 4 are shown in the same size as those in Figs. 2 and 3 for easy depiction. When using this nozzle, it is desired from the standpoint of reducing the release of liquid nitrogen which falls into space between the containers 6 to position the nozzle 4 with respect to the containers 6 being conveyed so that the liquid nitrogen released from the central row of outlets falls onto the diametrical line in the circle of the open top end of each container 6 parallel to the direction of travel of the containers. In this nozzle, the diameter of each ou,tlet is made smaller b~ a little less than 20 % as compared with that of Fig. 3 while maintaining the same total release rate as in the example of Fig. 3, and therefore the intensity of collision of the release from each outlet with the surface of ~2~5~Si[~
the liquid content in the container and the spattering of the liquid nitrogen to the outside of the container is reduced.
Fig. 5 is a fragmentary sectional view showing a different apparatus for carxying out the method according to the invention.
This apparatus is the same as that shown in Fig. 1 except for the bottom of the low-temperature liquefied gas storage tank 1 which now has two nozzles 4 provided in series in the direction of travel of containers. Each nozzle 4 has three outlets 5 arranged in a row parallel to the direction of travel of containers.
The purpose of this arrangement is to ensure that a predetermined ~uantity of liquid nitrogen is charged into each container 6 even when speed of travel of the containers is changed.
Containers are ordinarily moved through a filling line at two different speeds, high speed and half speed depend-ing on the condition of the line component machines and while the containers are being moved at high speed, the liquid nitro-gen may be released from all six outlets 5 of the two nozzles4.
On the other hand, while the containers are being moved at half speed, one of nozzies 4 may be shut off by means of a valve (not shown) and the liquid nitrogen is allowed to be released only from the remaining three outlets 5 of the other nozzle 4. In either case, the same quantity of liquid nitrogen can be charged into each container 6.
While in this example of an apparatus according to this invention each nozzle 4 has three outlets 5, it is more desirable to provide a greater number o outlets as mentioned above.
The nozzle described above has a plurality of outlets ~2~59~0 which are arranged along a perfectly straight line. However, these outlets may be arranged at such angles respectively that the liquefied gas released from each of the outlets falls onto a substantially straight line. This will be described in further detail in connection with, for instance, a nozzle having three outlets. The three outlets may be so arranged that the two on the leading and trailing end of the nozzle, for example, are positioned on a line perfectly parallel to the direction of travel of containers and directed perfectly downwardly and the remaining outlet is positioned slightly o~f the above line but directed at such an angle that the low-temperature liquefied gas released from all these outlets falls onto a straight line on the surface of liquid content in the container.
In this arrangement, the low-temperature liquefied gas released from the outlets other than the one on the leading end of the nozzle may fall on the same position of content liquid surface in the container as the liquefied gas from the outlet on the leading end does.
In the above example the two outlets positioned on a line parallel to the direction of the travel of the containers may be tilted toward the other outlet (which may also be tilted toward the above two outlets) so that the liquefied gas releas-ed from all three outlets falls on a substantially strai~ht line on the surface of liquid content in the container.
These arrangements can result in the same effect as the arrangement with which all the outlets are aligned.
In the method according to the invention, other liquefied gases than liquid nitrogen in the above embodiments, e.g., liquid argon, ma~ be used as well. The container may be metal containers or plastic containers having a single-layer wall structure, a double-layer wall structure or a wall struc-ture consisting of more than two layers or composite containers ~!L2~S9S~
consisting of a variety of co~binations of metal foils, papersheets, plastic sheets, etc.
Further, after a low-temperature liquefied gas is charged into the container having content therein and before the time the container is sealed, the air remaining in the con-tainer is purged by the gas resulting from the vaporization of the liquefied gas.
Thus, an effect of preventing the deterioration of the containered liquid food or the like content during storage is attained. For this reason the invention can be applicable not only to the hot filling process but also to the cold filling process to obtain high quality containered gas-sealed contain-ered food.
The present invention relates -to a method o~ manu-fac-turing pressurized, sealed containered food by charging a predetermined quanti-ty of liquefied nitrogen through a lique-fied nitrogen outlet into individual containers, which are s-till open at the -top and have already a predetermined quanti-ty of food including liquid content while the containers are successively travelling at a constant speed and then sealing each con~ainer with a lid.
By the term "containered food" is meant canned food, bottled food or the like, and by the term "pres~urized, sealed contain-ered food" is meant for example, a canned food containing food (e.g., solid food plus syrup) together with a low-temperature liquefied gas.
A method of charging a predetermined quantity of a low-temperature liquefied gas is sought in various industrial fields. Particularly, a method of charging an inert low-temperature liquefied gas is desired not for packing frothable liquid food containing CO2 gas, e.g., beer, in containers but for packing non-frothable liquid food, (e.g., fruits in syrup;
juice drinks; orange drinks containing orange sacs; and coffee drinks) by means of, for example, hot filling process.
With a hot filled product in a can or the like, the can becomes depressed or convex when a negative pressure is generated as the temperature of the content falls after its sealing with a lid. Accordingly, the thickness of the can body is made sufficiently large so that it will not become de-pressed even when a negative pressure is generated. Recently, however in order to use cans having a thin body, i-t has been proposed to charge a predetermined quantity of an inert gas in the liquid state (which does not change the taste of the contents, such as liquid nitrogen) into the can containing a non-frothable drink filled while it is hot, so that pressure ~ . . .
-- 1 -- .j, ~2~595~
in the can is higher than atmospheric pressure after the can has been sealed and the content has been cooled down (at which time the liquefied gas is vaporized).
ur~C~
In the method of manufacturing ga~-sealed con~ainered food, in which an inert low-temperature liquefied gas (herein-after referred to merely as low-temperature liquefied gas) is continuously charged into containers at high speed, there are problems.
In this method~ a low-temperature liquefied gas is charged into containers while the containers are being moved at high speed. Therefore, the charged low-temperature liquefied gas is partly spattered to the outside of the containers and also partly vaporized to escape from the containers. Where the low-temperature liquefied gas is continuously released, it also falls into space between containers. With this method, therefore, considerable loss of low-temperature liquefied gas results. In addition, the quantity of low-temperature lique-fied gas that is retàined in individual containers fluctuates greatly.
To be more specific, the low-temperature liquefied gas has very low boiling point. (For example, liquid nitrogen has a boiling point of approximately -196C, and liquid argon has a boiling point of -186C at the atmospheric pressure). While the low-temperature liquefied gas as released from an outlet flows toward the surface of the liquid in the container, the low-temperature liquefied gas is partly vaporized due to exposure to the surrounding atmosphere. It is also partly vaporized when it comes into contact with the liquid content. The re-sultant vaporized gas escapes to the outside of the container.
Further, when the low-temperature liquefied gas strikes the surface of the content in the can, the low-temperature lique-fied gas is partly spattered to the outside thereof by the ~Z~LS9~) striking impact. Still further, it is partly spattered by a blow~out action of sudden vaporization just when it reaches surface on the content. For the above reasons, a considerable amount of low-temperature liquefied gas is lost.
Moreover, the quantity of low-temperature liquefied gas (or evaporated gas) that remains in the container after the sealing thereof with a lid fluctuates greatly among indi-vidual containers.
Generally, volume of the low-temperature liquefied gas which is vaporized immediately after its release from the outlet and until it comes into contact with liquid content in the container is in proportion to the area of exposed surface of the released low-temperature liquefied gas.
From this standpoint, i.e., from the standpoint of reduction of the vaporization it has been considered to date that it is the best method to let a predetermined quantity of low-temperature liquefied gas be released from a single nozzle having a single outlet.
7 r - z c~
With this method of manufacture of~ga~-sealed con-tainered food, however, a great deal of low-temperature lique-fied gas is still lost, and quantity of the gas retained in the container fluctuates greatly among individual containers.
Therefore, this method has not been commercially used. To overcome the above disadvantage, there has been proposed a method, in which the velocity at which the low-temperature liquefied gas reaches the content in the can, does not exceed 350 cm/sec. (as disclosed in Japanese Patent Open Publication No. 161915/81~.
~ccording to this proposed method, the loss of low-temperature liquefied gas can be reduced to some extent. How-ever, the loss is still considerable, and also the quantity of low-temperature liquefied gas (vaporized gas) retained, in ,- 12~5g~
the container fluctuates greatly.
The present invention provides a method of manu~actur-ing pressurized, sealed containered food, which can reduce -the fluctuations of the quali-ty of low-temperature liquefied gas retained in individual containers to a small range.
The present invention also provides a method of manufacturing pressurized, sealed containered food, which can reduce -the loss of low-temperature liquefied gas released from an outlet and charged into containers.
According to one aspect thereof the invention provides a method of manufacturing pressurized, nitrogen gas-sealed containered food, the internal pressure of the container after the sealing thereof being greater than the atmospheric pressure, by charging liquefied nitrogen in a predetermined quantity continuously through an outlet for releasing said liquefied nitrogen into each of said containers, said containers successively travelling at a constant speed, each having a predetermined quantity of food including liquid content and being open at the circular top end, said liquefied nitrogen making the internal pressure of the containers after the sealing thereof greater than the atmospheric pressure, and subsequently sealing each of said containers with a lid, wherein said liquefied nitrogen is released continuously onto the content liquid surface from a plurality of outlets arranged in a row extending substantially parallel to the direction of travel of the containers and being above the diametrical line of said circular top end or above near said diametrical line, thereby allowing the liquefied nitrogen released from each of the outlets to pass above substantially said diametrical line of the circular top end, and further allowing the liquefied nitrogen released from each of the ou-tlets in one row to fall, one after another, onto substantially the same position on the content liquid surface.
S9~
In a particular embodiment of the present invention the liquefied nitrogen is released from a plurality of outlets arranged in a plurality of rows extending substan-tially parallel to -the direction o~ travel of the containers.
~ he present invention will be further illustrated, by way of the accompanying drawings, in which:-Fig. 1 is a fraymentary sectional view showing oneembodiment of apparatus for carrying out the method according to the invention;
E~ig. 2 is a bottom view showing a nozzle of the apparatus shown in Fig. l;
Fig.s 3 and 4 are bottom views showing other examples of the nozzle in other embodiments of apparatus for carrying out the method according to the invention;
Fig. 5 is a framentary sectional view showing another embodiment of apparatus for carrying out the method according to the invention; and Fig. 6 is a bottom view showing a nozzle in an appara-tus used for experiments carried out for the purpose of compar-ing the results obtained according to the invention.
In the Figures, arrows indicate the direction of travelof containers.
Ihe inventors have conducted extensive experiments and found that when releasing low-temperature liquefied gas through the outlet of a nozzle into containers having liquid content while the containers are being moved, the spat-tering and rapid or drastic vaporization of the released low-temperature liquefied gas due to collision thereof with liquid surface of content increase in proportion to the intensity of ~ ~L2~S9S~
collision.
The inventors have also found that the release of the low-temperature liquefied gas through a plurality of outlets will reduce the intensity of collision of the liquefied gas with the content liquid surface and suppress the spattering and drastic vaporization of the liquefied gas in a much more effective manner than the release through a single outlet, provided that the quantity of low-temperature liquefied gas to be released is the same.
As mentioned earlier, the vaporization of the lique-fied gas released from the outlet until it reaches the content liquid surface in the can is proportional to the area of ex-posed surface of the liquefied gas.
That is, when a predetermined amount of the lique-fied gas is charged into the can from a plurality of outlets and a single outlet respectively, the area of exposed surface of the liquefied gas released from a plurality of outlets is essentially larger than that from the single outlet, so that the plurality of outlets allow greater vaporization of the liquefied gas than the single outlet does This means that in order to minimize the possible disadvantage of a method using a plurality of outlets as above the outlets must be set as close to the top of the container as possible. Desirably, this distance is set to be less than approximately 35 mm, or more preferably, less than 10 mm. By this setting of the outlets the intensity of collision noted earlier is reduced to such extent that velocity of the released liquefied gas suppresses the spattering and the like, whereby the possible disadvantage of a method of using a plurality of outlets can be successfully overcome.
The first aspect of the present invention is based on the above findings.
- ~2~LS~
The inventors have further found as a result of ex-periments if the pluralit~ of outlets are arranged in a row extending substantially parallel to the direction of travel of containers having the liquid content which are travelling with their top end open, the spatteriny and sudden vaporization of the low-temperature liquefied at the time of the collision thereof with the content liquid surface in the container can be reduced as compared with the case of other arrangements.
In addition, reduction of fluctuations of the pressure in the container after the sealing thereof can also be obtained.
The second aspect of the present invention is based on the above findings.
Reasons that the arrangement of the outlets in a row extending substantially parallel to the direction of pro-gress of the successively travelling containers having liquid content with its top open can reduce the spattering~ vaporiza-tion of the low-temperature liquefied gas and fluctuations of the inner pressure of the container after the sealing thereof have not been clearly elucidated. However, conceivable reasons are as follows. With the arrangement noted above, the low-temperature liquefied gas, which is released from the respec-tive outlets, can successively fall into substantially the same position of the content liquid surface at a very short time interval. To be more specific, the low-temperature lique-fied gas released from the first outlet in the row, the outlet on the left hand end of the row in Fig. 1, in the direction of travel of the containers falls onto the content liquid surface at a position thereof. Then the liquefied gas released from the second outlet also falls onto substantially the same posi-tion as that of the above content liquid surface. Likewise,the liquefied gas released from the third, fourth and so forth outlets successively falls onto substantially the same position -- lZ~59~
as above. The low-temperature liquefied gas released from the second outlet and thereafter thus falls on the liquefied gas which has already been charged into the container. It is thought that this has an effect of reducing the vaporization of the low-temperature liquefied gas at the time of collision thereof with the content li~uid surface and also reducing the spattering of the liquefied gas caused by the sudden vaporiza-tion of the liquefied gas.
Further, where the container to which the low-temper-ature liquefied gas is to be charged has a cylindrical shapelike a can or has a circular or oval open top end, the outlets may be arranged along a line which is substantially parallel to the direction of travel of the containers and also substan-tially parallel to the diametrical line of the container. In this case, even if the low-temperature liquefied gas is re-leased continuously, it substantially falls onto the diamet-rical line, of the container, where the spaces between con-tainers are naturally kept to a minimum. Thus, the quantity of the low-temperature liquefied gas falling into the spaces be-tween adjacent containers can be reduced.
An embodiment of the invention will now be described with reference to the drawings.
A low-temperature liquefied gas storage tank 1 has a double-wall heat-insulating structure having inner and outer walls 2 and 3. A space between the walls 2 and 3 is evacuated.
The bottom of the storage tank 1 has a nozzle 4, through which a low-temperature liquefied gas is released down.
The nozzle 4 has outlets 5. In the example shown in Figs. 1 and 2, five outlets are provided in a row along a straight line.
Reference numeral 6 designates containers into which a liquid content has already been filled. In the examples, two-piece cans are shown. These containers 6 are supported at S95~
their body portion by respective pawl members 7 attached at a uniform interval to an endless chain (not shown) which travels at a constant speed.
Reference numeral 8 designates a guide rail which restricts mo~ement of the containers in directions perpendicu-lar to the direction of their travel. Reference numeral 9 designates a table, on which the containers are slidably moved.
The individual outlets 5 are preferably arranged such that the center of the open top end of the containers 6 moves past these outlets 5. (For example, in case of contain-ers having a circular open top end, the diametrical line through the container parallel with the direction of travel thereof is preferably vertically overlapped by the row of the outlets 5.
The surface of the low-temperature liquefied gas in the storage tank 1 is subjected to an atmospheric pressure, and the level of the liquefied gas is controlled substantially constantly by a level control sensor and an electromagnetic valve (these being not shown). Thus the total amount of the low-temperature liquefied gas released from the outlets 5 per unit time is held substantially constant.
With this apparatus, the low-temperature liquefied gas can be released at a substantially constant rate (ml/sec.).
Accordingly, a constant quantity of low-temperature liquefied gas can be charged into the individual containers if the con-tainers with the top ends open are moved at a constant speed right under the outlets releasing the liquefied gas continu-ous ly .
As soon as the low-temperature liquefied gas is charged into each container, the container is immediately sealed by a well-known method and apparatus to prevent the charged liquefied gas from bein~ dispersed to atmosphere by its vaporization and thus a constant gas pressure in the _ g _ .59~
container is maintained.
Example 1 Cans having a diameter of approximately 52.6 mm (or commonly termed 202 diameter), a height of approximately 132 mm and a capacity of 250 ml were used. A juice drink containing 10% of orange juice was used as the liquid content. The juice drink is poured at a temperature of 95C into each can to leave a predetermined head space. The individual cans thus filled with the juice drink were immediately moved at a rate of 450 cans per minute (with adjacent cans spaced apart by approximately 5 cm) past a position right under liquid nitro-gen releasing outlets. Six liquid nitrogen releasing noz71es having different outlet arrangements A to F as listed in Table 1 below were used (the arrangement A being a contrast). The liquid nitrogen continuously released from the nozzle is charged into the moving cans. Each can was then sealed immedi-ately with an easy-open lid by the use of a sealing machine.
Approximately 1.8 seconds was taken to start sealing of the can since it had just past under the outlets.
The distance from the liquid surface of the liquid nitrogen storage tank to the bottom end of the outlet was con-trolled to approximately 110 mm. The distance from the bottom end of the outlet to the top end of each can moving under the outlet was set to 5 mm (the head space of each can being set to 12 mm). Under the conditions described above, the flow rate of liquid nitrogen at the points of release from outlets was measured. The results are listed in Table 1.
Table 1 = _ A B C D E F
Number of outlets 1 2 3 5 8 12 Outlet diameter (mm) 1.7 1.2 1.0 0.8 0.6 0.5 Flow rate tml~sec.) 2.54 2.56 2.62 2.56 2.58 2.55 - ~.2~LS~
In the outlet arrangements B, C and D, the outlets are arranged in a row extending parallel to the direction of travel of cans. In the arrangement E, the outlets are arrang-ed in two rows each having four outlets, and in the arrange-ment F outlets are arranged in three rows each having four outlets, extending parallel to the direction of travel of cans.
After the cans having the liquid content and liquid nitrogen therein were sealed, they wexe cooled down to room temperature. Then, the inner pressure in 25 cans tested by means of the outlet arrangements A to F were measured. The results are shown in Table 2.
Table 2 (n=2~) A B C D E F
pressure (kg/cm2) 1.21 1.31 1.47 1.69 1.55 1.68 Fluctuation 0.5- 0.7- 1.1- 1.5- 1.5 ~ 1.5-range kg/cm2~ 1.6 1.7 1.8 1.9 1.9 1.9 _ deviation (kg/cm2) 0.26 0.20 0.17 o.ll 0.12 0.11 It will be readily appreciated from Table ~ that higher inner pressure can be obtained with two or more outlets than with a single outlet. This means that a greater quantity of liquid nitrogen remains in the can in the case where two or more outlets are provided.
In addition, in the case o using two or more out-lets, it is shown that the inner pressure fluctuation becomes smaller, which generally means more stable quality of the con-tainered food.
This favorable result is appreciated to be attribut~
able to the effect of the provision of a plurality of outlets as all outlet arrangements in the examples are set to the same conditions in terms of amount and flow rate of released liquid nitro~en ( the same level of liquid nitxogen under atmospheric ` ~ 12159S~
pressure and the same distance from the outlets to the top end of the cans for all arrangements).
As has been shown, by means of provision of two or more low-temperature liquefied gas outlets a larger amount of the charged low-temperature liquefied gas is retained in the can ~the retained liquefied gas is soon vaporized after the sealing of the can) as compared with the provision of a single outlet in accordance with the prior art.
The desired amount of liquefied gas thus can be re-tained in the can with a lesser amount of the low-temperature liquefied gas to be released.
Increased quantity of the liquefied gas to be retain-ed in the can or decreased lose of released liquefied gas caus-ed by spattering, vaporization etc. means that it is possible to narrow the range of fluctuations of the amount of the lique-fied gas to be retained in the sealed can, which gives an effect of reducing possibility of defects of canned food such as swelling of the can lid due to excess liquefied gas or depres-sion of the can body due to insufficient liquefied gas sealed in the can.
The plural number of outlets provided in this inven-tion may be N in a single nozzle or N/M in a plural number tM) of nozzles. It is further possible to provide different num-bers of outlets in respective M nozzles. Here M and N are re-spectively a naturalnumber which is more than 2.
Experiment Cans in 202 diameter having a capacity of 250 ml identical with the can in Example 1, were used. Water at 93C
was poured into each can to leave a head space of approximately 13 mm. The individual cans were then conveyed immediately at a rate of 1,200 cans per minute under liquid nitrogen outlets and then each sealed with an easy-open lid. Approximately ~z~s~
0.5 seconds was taken to start sealing of the can since it hadjust past under the outlets.
The li~uid nitrogen releasin~ apparatus used, in this experiment has two nozzles each having two rows of five outlets of 0.5 mm in diameter arranced along a line extending substantiall~ parallel to the direction of travel of cans. The total releasing amount was set to 5.6 ml/sec. The experiment was carried out by changing the distance between the bottom of the rows of outlets and the can top end to 1, 5, 10, 25, 35 and 50 mm respectively, and the average inner pressure and pres-sure ~luctuations in the cans were measured. The results are shown in Table 3 below.
Table 3 Distance from Average inner Fluctuation Standard outlet end to pressure ~ range of inner deviation2 can top end (kg/cm ) pressure ~ (kg/cm ) (mm) (kg/cm ) 1 1.55 1.4 -1.7 O.Og 1.53 1.3,-1.8 0.11 1.47 1.2 ~ 1.7 0.14 1.43 1.1~ 1.6 0.15 1.41 1.0~1.7 0.18 Average value Average value was was not calcu- not calculated lated because because the maxi-paneling occur- mum was 1.6 while ed in two cans. the minimum was minus.
* Measurement was done for 15 cans for each distance.
It will be appreciated from the results of the experi-ment that when the low-temperature liquefied gas is charged into a can already filled with a liquid content leaving an ordinary head space, it is necessary to set the distance from the bottom of the outlet to the can top end to 35 mm or below, preferably 10 mm or below in order to allow smaller loss of 5~
the low-temperature liquefied gas and fluctuations of the inner pressure in the can.
Example 2 This example pertains to the second aspect of the invention mentioned above.
In this example, tin plate DI cans of approximately 52.6 mm diameter (202 diameter), approximately 132 mm of height with 250 ml capacity were used.
Approximately 240 g (more specifically 240 - 1 g) of water at 90C was poured into the DI cans at a rate of 450 cans per minute. Liquid nitrogen was then charged into these cans while they were being moved at the same speed of 450 cans per minute under various arrangements of the liquid nitrogen nozzle units as shown below, and immediately thereafter the cans were sealed each with an easy-open lid using a sealing machine.
Conditions of Experiment Quantity of liquid nitrogen charged - approximately 0.22 ml per can Time taken from the completion of charging of li~uid nitrogen to the start of sealing - 1.8 seconds Distance from the bottom of the outlet to the top of S ~n ,n the can flange (vertical distance) - approximatelyq~
Level of liquid nitrogen in the storage tank - approx-imately 140 mm Nozzle unit specifications (i~e., number and diameter of outlets), outlet pitch (center-to-center distance between adjacent outlets) - as listed in Table 4 (in the Examples G, H, I and J, the outlets were 5 in number and 0.8 n~ in diameter and spaced apart at a pitch of 2.5 mm, while in Example K the outlets were 12 in number, 0.52 mm in diameter and spaced apart at a pitch of 2.02 mm.) ~2~S~O
In the nozzle unit G the outlet row was arranyed to substanti~lly vertically overlap the diametrical line of the open can top parallel to the direction of travel of cans.
Result of Ex~riment Table 4 shows the measurements of average inner pres-sure in the can, ~luctuation range thereof and standard devia-tion.
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It will be appreciated from Table 4 that with the same number of outlets texamples G, H, I and J) the highest average inner pressure (1.82) in the cans and the smallest inner pres-sure fluctuation range (0.5 or the balance of max. 2.~ and min.
1.5) can be obtained by means of the outlet arrangement in a row parallel to the direction of travel of cans (example G).
The closer to a line parallel to the direction of travel of cans, the row of outlets are arranged, the higher is the average inner pressure in the cans and the smaller is the inner pressure fluctuation range.
Since the total rate of release of liquid nitrogen was the same with all the nozzle units used, it is appreciated that the higher average inner pressure in the can means the lesser loss of li~uid nitrogen released from the outlets.
One of the reasons for the lesser loss is thought to be attributable to the reduction of spattering and sudden vap-orization of the liquid nitrogen released from .he outlets at the time of the collision of the released liquefied gas with the surface of the content in the can. Another conceivable reason is that the released liquefied gas which falls into space between adjacent can is decreased as the row of outlets runs closer to a line parallel to the direction of the travel of cans as the cans are cylindrical and the farther the row o outlets is set off the diametrical line of the open top end of the can parallel to the direction of travel of cans, the great-er is the quantity of released liquefied gas directed to the outside of the can. Further, it will be appreciated from the comparison of the results in the examples K and G that lesser loss o~ liquid nitrogen and inner pressure fluctuation range can be obtained by reducing the diameter of each outlet and the rate of release per outlet while maintaining the same total release rate.
~Z~5~5~
(Outlets in Fig. 3 are shown in the same size as those in Fig. 2 for easy depiction.) This is thought to be attributable to the reduction of the inte~sity of collision of the liquid nitrogen released from each outlet with the surface of the liquid content in the can, and hence the reduction of the loss or spattering of liquid nitrogen toward the outside of the can.
In the case of arxangement K, it is desirable from the standpoint of reducing the released liquid nitrogen which falls into space between the cans that the nozzle 4 is so positioned with respect to the cans 6 being conveyed that the liquid nitrogen released from the respective rows of outlets falls onto opposite sides of the diametrical line of the circle of the open top end of the cans 6.
Fig. 4 is a bottom view of another nozzle which is used for carrying out the method according to the invention.
This nozzle has a total of eighteen outlets 5 arranged in three rows each having six outlets and extending parallel to the di-rection of travel of containers as shown by arrows. Outlets in Fig. 4 are shown in the same size as those in Figs. 2 and 3 for easy depiction. When using this nozzle, it is desired from the standpoint of reducing the release of liquid nitrogen which falls into space between the containers 6 to position the nozzle 4 with respect to the containers 6 being conveyed so that the liquid nitrogen released from the central row of outlets falls onto the diametrical line in the circle of the open top end of each container 6 parallel to the direction of travel of the containers. In this nozzle, the diameter of each ou,tlet is made smaller b~ a little less than 20 % as compared with that of Fig. 3 while maintaining the same total release rate as in the example of Fig. 3, and therefore the intensity of collision of the release from each outlet with the surface of ~2~5~Si[~
the liquid content in the container and the spattering of the liquid nitrogen to the outside of the container is reduced.
Fig. 5 is a fragmentary sectional view showing a different apparatus for carxying out the method according to the invention.
This apparatus is the same as that shown in Fig. 1 except for the bottom of the low-temperature liquefied gas storage tank 1 which now has two nozzles 4 provided in series in the direction of travel of containers. Each nozzle 4 has three outlets 5 arranged in a row parallel to the direction of travel of containers.
The purpose of this arrangement is to ensure that a predetermined ~uantity of liquid nitrogen is charged into each container 6 even when speed of travel of the containers is changed.
Containers are ordinarily moved through a filling line at two different speeds, high speed and half speed depend-ing on the condition of the line component machines and while the containers are being moved at high speed, the liquid nitro-gen may be released from all six outlets 5 of the two nozzles4.
On the other hand, while the containers are being moved at half speed, one of nozzies 4 may be shut off by means of a valve (not shown) and the liquid nitrogen is allowed to be released only from the remaining three outlets 5 of the other nozzle 4. In either case, the same quantity of liquid nitrogen can be charged into each container 6.
While in this example of an apparatus according to this invention each nozzle 4 has three outlets 5, it is more desirable to provide a greater number o outlets as mentioned above.
The nozzle described above has a plurality of outlets ~2~59~0 which are arranged along a perfectly straight line. However, these outlets may be arranged at such angles respectively that the liquefied gas released from each of the outlets falls onto a substantially straight line. This will be described in further detail in connection with, for instance, a nozzle having three outlets. The three outlets may be so arranged that the two on the leading and trailing end of the nozzle, for example, are positioned on a line perfectly parallel to the direction of travel of containers and directed perfectly downwardly and the remaining outlet is positioned slightly o~f the above line but directed at such an angle that the low-temperature liquefied gas released from all these outlets falls onto a straight line on the surface of liquid content in the container.
In this arrangement, the low-temperature liquefied gas released from the outlets other than the one on the leading end of the nozzle may fall on the same position of content liquid surface in the container as the liquefied gas from the outlet on the leading end does.
In the above example the two outlets positioned on a line parallel to the direction of the travel of the containers may be tilted toward the other outlet (which may also be tilted toward the above two outlets) so that the liquefied gas releas-ed from all three outlets falls on a substantially strai~ht line on the surface of liquid content in the container.
These arrangements can result in the same effect as the arrangement with which all the outlets are aligned.
In the method according to the invention, other liquefied gases than liquid nitrogen in the above embodiments, e.g., liquid argon, ma~ be used as well. The container may be metal containers or plastic containers having a single-layer wall structure, a double-layer wall structure or a wall struc-ture consisting of more than two layers or composite containers ~!L2~S9S~
consisting of a variety of co~binations of metal foils, papersheets, plastic sheets, etc.
Further, after a low-temperature liquefied gas is charged into the container having content therein and before the time the container is sealed, the air remaining in the con-tainer is purged by the gas resulting from the vaporization of the liquefied gas.
Thus, an effect of preventing the deterioration of the containered liquid food or the like content during storage is attained. For this reason the invention can be applicable not only to the hot filling process but also to the cold filling process to obtain high quality containered gas-sealed contain-ered food.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing pressurized, nitrogen gas-sealed containered food, the internal pressure of the container after the sealing thereof being greater than the atmospheric pressure, by charging liquefied nitrogen in a predetermined quantity continuously through an outlet for releasing said liquefied nitrogen into each of said containers, said containers successively travelling at a constant speed, each having a predetermined quantity of food including liquid content and being open at the circular top end, said liquefied nitrogen making the internal pressure of the containers after the sealing thereof greater than the atmospheric pressure, and subsequently sealing each of said containers with a lid, wherein said liquefied nitrogen is released continuously onto the content liquid surface from a plurality of outlets arranged in a row extending substan-tially parallel to the direction of travel of the containers and being above the diametrical line of said circular top end or above near said diametrical line, thereby allowing the liquefied nitrogen released from each of the outlets to pass above substantially said diametrical line of the circular top end, and further allowing the liquefied nitrogen released from each of the outlets in one row to fall, one after another, onto substantially the same position on the content liquid surface.
2. The method of manufacturing pressurized, nitrogen gas-sealed containered food according to claim 1 wherein said liquefied nitrogen is released from a plurality of outlets arranged in a plurality of rows extending substantially parallel to the direction of travel of the containers.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6331982A JPS58180401A (en) | 1982-04-16 | 1982-04-16 | Adhesive composition for capturing small life |
| JP66318/82 | 1982-04-22 | ||
| JP57066318A JPS58183418A (en) | 1982-04-22 | 1982-04-22 | Manufacture of gas enclosed can |
| JP63319/82 | 1982-04-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1215950A true CA1215950A (en) | 1986-12-30 |
Family
ID=26404418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000426380A Expired CA1215950A (en) | 1982-04-16 | 1983-04-21 | Plural anti-splash injection streams in liquid gas food sealing systems |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1215950A (en) |
-
1983
- 1983-04-21 CA CA000426380A patent/CA1215950A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |