CA1073797A - Process for packaging food - Google Patents
Process for packaging foodInfo
- Publication number
- CA1073797A CA1073797A CA248,939A CA248939A CA1073797A CA 1073797 A CA1073797 A CA 1073797A CA 248939 A CA248939 A CA 248939A CA 1073797 A CA1073797 A CA 1073797A
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- CA
- Canada
- Prior art keywords
- chamber
- unit
- gas
- opening
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B31/00—Packaging articles or materials under special atmospheric or gaseous conditions; Adding propellants to aerosol containers
- B65B31/02—Filling, closing, or filling and closing, containers or wrappers in chambers maintained under vacuum or superatmospheric pressure or containing a special atmosphere, e.g. of inert gas
- B65B31/021—Filling, closing, or filling and closing, containers or wrappers in chambers maintained under vacuum or superatmospheric pressure or containing a special atmosphere, e.g. of inert gas the containers or wrappers being interconnected
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- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vacuum Packaging (AREA)
- Containers And Plastic Fillers For Packaging (AREA)
Abstract
CCB:ji Case 5697 PROCESS FOR PACKAGING FOOD
ABSTRACT OF THE DISCLOSURE
A process for packaging units of food in which the food units are placed on a bottom film and slits made in the film. The film with the food units thereon is passed into an open chamber, the chamber closed and a vacuum drawn on it followed by back-filling with a sub-stantially oxygen-free gas. The film with the food units thereon and a top film over the units is then subjected to vacuum and the top and the bottom films sealed. Alter-nately the package may be back-filled with oxygen-free gas prior to being sealed about the food unit. The dis-closure includes also the steps of partially sealing food units between top and bottom films in a first chamber, back-filling with a substantially oxygen-free gas, then vacuumizing in a second chamber, and fully sealing the packages in the second chamber, or alternately back-filling with the oxygen-free gas before fully sealing.
ABSTRACT OF THE DISCLOSURE
A process for packaging units of food in which the food units are placed on a bottom film and slits made in the film. The film with the food units thereon is passed into an open chamber, the chamber closed and a vacuum drawn on it followed by back-filling with a sub-stantially oxygen-free gas. The film with the food units thereon and a top film over the units is then subjected to vacuum and the top and the bottom films sealed. Alter-nately the package may be back-filled with oxygen-free gas prior to being sealed about the food unit. The dis-closure includes also the steps of partially sealing food units between top and bottom films in a first chamber, back-filling with a substantially oxygen-free gas, then vacuumizing in a second chamber, and fully sealing the packages in the second chamber, or alternately back-filling with the oxygen-free gas before fully sealing.
Description
~ ~7 3~4~7 This invention relate~ to the packaging of foods and more particularly to a process in which a food ~nit is enclosed in fi~m and the amount and concentration of the oxygen within such fi~m is reduced.
BACRGROUND
It has long been recognized that the quall~y of foods can be mai~tained for extended periods of time if they may be stored i~ a~ en~ironment having reduced concen-trations of oxygen. Meat~ are e~pecially affect d by oxy-gen, and meat ite~s such as luncheon mea~s are extremely per-ishable in an atmosphere containiLng oxygen. In the pre~ence of o~ygen the food item, par~icu:Larly meats, loses flavor and tends ~o spoil ~ue to the growth of yeast, molds and some ba~teria that develop rapidly in ~he presence of oxygen even ~ri~g refrigerated storage. It is known that the vol~ne of oxygen about the food may be redllced by enclosing the food unit ln ilm having low oxygen permeability and seal-i~g while under a Yacuum. If the food u~it is placed in a chamber, a vacuum o 29 inches merc ~ drawn on th~ ch~m-~p ber a~d the film sealed a~out ~e unit when it is under ~acuum, a package may be obtained having a vacuum of about 24 ~o 26 i~ches mercury, but the concentra~ion of oxy~en withi~ the package r~mains at about 20%. For exam~le, in a 2-ounce pa~kage of bologna (~ slices) 0.47 ~o 0.99 cc of air having an oxyge~ concentration of 20% is lef~ in the packag2 apar~ from what may be in ~he meat body itself.
Thi~ amounts to 0.094 to 0.1~8 cc of oxygen. The oxygen is also entrapped within the meat. In the example of the ~,, ~73'~97
BACRGROUND
It has long been recognized that the quall~y of foods can be mai~tained for extended periods of time if they may be stored i~ a~ en~ironment having reduced concen-trations of oxygen. Meat~ are e~pecially affect d by oxy-gen, and meat ite~s such as luncheon mea~s are extremely per-ishable in an atmosphere containiLng oxygen. In the pre~ence of o~ygen the food item, par~icu:Larly meats, loses flavor and tends ~o spoil ~ue to the growth of yeast, molds and some ba~teria that develop rapidly in ~he presence of oxygen even ~ri~g refrigerated storage. It is known that the vol~ne of oxygen about the food may be redllced by enclosing the food unit ln ilm having low oxygen permeability and seal-i~g while under a Yacuum. If the food u~it is placed in a chamber, a vacuum o 29 inches merc ~ drawn on th~ ch~m-~p ber a~d the film sealed a~out ~e unit when it is under ~acuum, a package may be obtained having a vacuum of about 24 ~o 26 i~ches mercury, but the concentra~ion of oxy~en withi~ the package r~mains at about 20%. For exam~le, in a 2-ounce pa~kage of bologna (~ slices) 0.47 ~o 0.99 cc of air having an oxyge~ concentration of 20% is lef~ in the packag2 apar~ from what may be in ~he meat body itself.
Thi~ amounts to 0.094 to 0.1~8 cc of oxygen. The oxygen is also entrapped within the meat. In the example of the ~,, ~73'~97
2-ounce bologna package, the meat itself contains 0.16 to 0.33 cc of entrapped and absorbed air, which Computes to 0.032 to 0.066 cc oE oxygen. This comes to a total of 0.125 to 0.264 cc of oxygen still contained within th~
typical vacuumized package previously known in the art.
Such a package is known to have a shelf life, under ordin-ary marketing conditions, of from 30 to 60 days.
We have sought to discover processes for packaging units of food in a film enclosure in which the volume and concentration of oxygen within the package and in the food unit is substantially reduced from that of the prior prac-tice as above explained and which will result in packages which have a much longer shelf life. This discovery and other objects and advantages of my invention will become apparent as this specification proceeds.
The pres~nt invention is defined as a process for packaging foods comprising passing a bottom film with a unit of food thereon into a first chamber; drawing a vacuum in the first chamber, backfilling the first chamber with a gas ~ ?
which is substantially free of oxygen until the pressure with-in the chamber is substantially that which surrounds the first chamber; passing the bottom film and food unit out of the first chamber; passing the food unit with the bottom film beneath and a top film above the food unit into a second -~
chamber, drawing a vacuum in the second chamber; and sealing ~;~
the top and bottom films together about the food unit while still in the second chamber.
DETAILED DESC~IPTION
Suitable apparatus for use in the conduit of our 3Q invention is contained in the accompanying drawings in which--rw/~
. : - ,. , , ~ . .
~ at737~
Fig. 1 is an overall front perspective view of ~he machine;
Fi~. 2 is a schematic perspective view illustrating the principal apparatus units which act in sequence to prepare the improved packa~e;
Fig. 3 is a detailed schematic representation show- -ing the placement of food units and the location of slits - 2a -rw/~
, :-:
1~'73~7 in the lower film;
Fig. 4 is a detailed sehematic view of the knife below the lower film and th~ direction the knife moves to cut the slit in the lower film and then to withdraw;
Fig. 5 is a ~chematic view showi~g ~he position ;h of the openings for w~thdrawing and admitting gas with respec~ to the films and food units, and the lines of seal-ing in the firs t cham~er;
~ ` Pig. 6 is a detailed planar view of the openings ,t' 1~ to the gas passages in the first and second chambers;
Fig. 7 is a vertical sectional view~as seen from line 7-7 of Fig. 6 and showing also the~relative posi~ion of the top and bot~om films and illustrating~the slot contained in the lower fi~m;
Fig. 8 is also a vertical sectional view but as se~n from line 8-8 in Fig. 6;
Fig. 9 i~ an enlarged view similar to Fig. 8, but showing the ~lit i~ the.lower film and h~w the edges are drawn down;
` ~ Fig. lO is a detailed perspective view o~ a nozzle intended to engage the 51it in the lower film;
Fig. 11 is~ a sectional view of the nozzle taken as se~n ~rom line 11-11 of Fig. 10; -- --Fig. 1~ is a schema~ic view illustrating ~he en-gagement of the nozzle wlth a slit in the Iower film; and Fig. 13 is a detailed perspect~ve view showing the condition of the web when it comes ou~ of the second chamber.
.
~7 ~
As illustrated, the apparatus includes a cutter unit C for providing slit~ in the l~wer film, a firs~
chamber D, a gas-flushing area E, a second chamber F, and a cutting area G at which the films are cut to make indi-vidual packages.
R~ferring to Figs. 1 and 2, the machi~e has a frame 10 supported by the legs 11 and 12, and carried in the ~rame axe ~he section~ or units C, D, E, F and ~.
Above ~rame 10 is the con~rol panel P.
A roll of fi~m 13 is r~tatably mounted at the input end of the machine, and the film coming from this roll is passed forwardly over the top of the horizontal table of the machine. Thi~ film, designated 13, becomes the bottom of th~ package. As the film 13 passes forwardly over the tabl~ at the input end of th~ machine, there is placed upon i~ ~paced food un~ts 14 each of whi~ may in-clude, for example, ~wo l-ou~c~ slices of bologna. The bottom ~ilm 13 with the food units ther~on pas~es orwardly through cutter ~ection G, then through ohamber D, then to area E which is betwe~n chambers D and F, then through oh~mber F and c~mes to the section G where it is cut.
A second roll of film 15 ls ro~atably moun~ed above frame 10 a~d the top fi~n 16 from this roll is led under the roll 17 where it forms a co~er over the food units and mo~es forwardly along with the food units and the bo~-tom film 13 through ~he sections D, E, F and G.
.
~.~737~7 Although the roll 17 which introdu~es ~he film 16 to its position on top of th~ food units, is lllus-trated as loca~ed back of the firs~ chamber D, this roll could be loca~ed Otl the forward side of chamber D. Pre-ferably this roll is located as it is illus~rated.
In the embodiment illu~trated the machine is designed to advarlce the films intermittently, eigh~ food u~its at a time, which involves two rows of units w:iLth four units in eaeh row. It is apparent that the machine 1~ could be designed to advance at one time any number of rows with any number o~ units in each row. Our proce~s is effective in the packaging of any food bu~ more particu~
larly meat products such as luncheon meats and similar items.
As illustrated, each advanoe of the fi~m passes eight units under the plate 18 of section C. Below plate 18 and ~nder bot~om film 13 are ~paced knives 19 (see Figs.
typical vacuumized package previously known in the art.
Such a package is known to have a shelf life, under ordin-ary marketing conditions, of from 30 to 60 days.
We have sought to discover processes for packaging units of food in a film enclosure in which the volume and concentration of oxygen within the package and in the food unit is substantially reduced from that of the prior prac-tice as above explained and which will result in packages which have a much longer shelf life. This discovery and other objects and advantages of my invention will become apparent as this specification proceeds.
The pres~nt invention is defined as a process for packaging foods comprising passing a bottom film with a unit of food thereon into a first chamber; drawing a vacuum in the first chamber, backfilling the first chamber with a gas ~ ?
which is substantially free of oxygen until the pressure with-in the chamber is substantially that which surrounds the first chamber; passing the bottom film and food unit out of the first chamber; passing the food unit with the bottom film beneath and a top film above the food unit into a second -~
chamber, drawing a vacuum in the second chamber; and sealing ~;~
the top and bottom films together about the food unit while still in the second chamber.
DETAILED DESC~IPTION
Suitable apparatus for use in the conduit of our 3Q invention is contained in the accompanying drawings in which--rw/~
. : - ,. , , ~ . .
~ at737~
Fig. 1 is an overall front perspective view of ~he machine;
Fi~. 2 is a schematic perspective view illustrating the principal apparatus units which act in sequence to prepare the improved packa~e;
Fig. 3 is a detailed schematic representation show- -ing the placement of food units and the location of slits - 2a -rw/~
, :-:
1~'73~7 in the lower film;
Fig. 4 is a detailed sehematic view of the knife below the lower film and th~ direction the knife moves to cut the slit in the lower film and then to withdraw;
Fig. 5 is a ~chematic view showi~g ~he position ;h of the openings for w~thdrawing and admitting gas with respec~ to the films and food units, and the lines of seal-ing in the firs t cham~er;
~ ` Pig. 6 is a detailed planar view of the openings ,t' 1~ to the gas passages in the first and second chambers;
Fig. 7 is a vertical sectional view~as seen from line 7-7 of Fig. 6 and showing also the~relative posi~ion of the top and bot~om films and illustrating~the slot contained in the lower fi~m;
Fig. 8 is also a vertical sectional view but as se~n from line 8-8 in Fig. 6;
Fig. 9 i~ an enlarged view similar to Fig. 8, but showing the ~lit i~ the.lower film and h~w the edges are drawn down;
` ~ Fig. lO is a detailed perspective view o~ a nozzle intended to engage the 51it in the lower film;
Fig. 11 is~ a sectional view of the nozzle taken as se~n ~rom line 11-11 of Fig. 10; -- --Fig. 1~ is a schema~ic view illustrating ~he en-gagement of the nozzle wlth a slit in the Iower film; and Fig. 13 is a detailed perspect~ve view showing the condition of the web when it comes ou~ of the second chamber.
.
~7 ~
As illustrated, the apparatus includes a cutter unit C for providing slit~ in the l~wer film, a firs~
chamber D, a gas-flushing area E, a second chamber F, and a cutting area G at which the films are cut to make indi-vidual packages.
R~ferring to Figs. 1 and 2, the machi~e has a frame 10 supported by the legs 11 and 12, and carried in the ~rame axe ~he section~ or units C, D, E, F and ~.
Above ~rame 10 is the con~rol panel P.
A roll of fi~m 13 is r~tatably mounted at the input end of the machine, and the film coming from this roll is passed forwardly over the top of the horizontal table of the machine. Thi~ film, designated 13, becomes the bottom of th~ package. As the film 13 passes forwardly over the tabl~ at the input end of th~ machine, there is placed upon i~ ~paced food un~ts 14 each of whi~ may in-clude, for example, ~wo l-ou~c~ slices of bologna. The bottom ~ilm 13 with the food units ther~on pas~es orwardly through cutter ~ection G, then through ohamber D, then to area E which is betwe~n chambers D and F, then through oh~mber F and c~mes to the section G where it is cut.
A second roll of film 15 ls ro~atably moun~ed above frame 10 a~d the top fi~n 16 from this roll is led under the roll 17 where it forms a co~er over the food units and mo~es forwardly along with the food units and the bo~-tom film 13 through ~he sections D, E, F and G.
.
~.~737~7 Although the roll 17 which introdu~es ~he film 16 to its position on top of th~ food units, is lllus-trated as loca~ed back of the firs~ chamber D, this roll could be loca~ed Otl the forward side of chamber D. Pre-ferably this roll is located as it is illus~rated.
In the embodiment illu~trated the machine is designed to advarlce the films intermittently, eigh~ food u~its at a time, which involves two rows of units w:iLth four units in eaeh row. It is apparent that the machine 1~ could be designed to advance at one time any number of rows with any number o~ units in each row. Our proce~s is effective in the packaging of any food bu~ more particu~
larly meat products such as luncheon meats and similar items.
As illustrated, each advanoe of the fi~m passes eight units under the plate 18 of section C. Below plate 18 and ~nder bot~om film 13 are ~paced knives 19 (see Figs.
3 and 4) which were in their downward or retracted posi-tion when the fi~m was advanc~d to this po~;ition. A~ the knives are ra~sed, they pUS}I the fi3m against a backup pad to cut sl~ts 20 in the i~m 13. The~e knives are ~ubse-queIltly lowered again af~er the sli~s ha~e been cut ~co per-mit the :Eilm to move withou~ interference the next time i~
i3 advanced. The slits cut in fllm 16 may va~y in siæe.
Ordlnarily they may be of 1:he order of 2 or 3 inchec in.
length but in the cases oi~ larger-sized food units, the sizes of the slits may be increa~ed.
.. . ..
1C~73791'7 The next advance of film 13 brings th~ two rows of food uni~s to a position between the uni~s C and D and the following ad~rance brings these same units into the ~irst chamber D, the lower section 21 of which is then in lowered position to open the chamber and permit the movement of the films together with the eight ~ood units into the chamber.
Then the section 21 is raised ~o close the cham-ber D, providing an airtight closure. The ~acuum lines 22 and ~3 are then opened. Line 22 leads from the h~ad of chamber D and line 23 leads from a pos1tion below the film 13. In this wa~ the vacuum o~ about 29 or 29~1/2 inches of mercury may be drawn in the chamber. Air is also drawn from t~e ~ood units through the slits and this air with-drawn ~hrough lines 23.
A~ thi~ point reference is made ~o Figs. S and 9. As the food uni~s and film come to the prescribed posi-tion within chamber D, s~ts in ~ilm 13 are immediately over a matrix 24 (Fig. 6) con~aining orifices 25. Orifices 25 are connected with line 23 to provide passages leading from below the slits to the source of the vacuum. A trough 26 having V-shaped~sides is provided in the top of this matrix. This tr~ugh is aligned with the slit in the film 13 t~ereabove and the orifices 25 are in th~ bottom of this trough.
When the vacuum is applied through passages in lines 23 air is withdrawn through ~lits 20 and the edges 1C~73797 of the sli~ 23a and 23b are drawn down against the inter-ior side of trough 26 (see Fig. 9) so as to enlarge the opening pravided by the ~lits.
After the vac~um ha~ been drawn, a partial seal is made bet:ween the top and bottom films within cha~ber D, the seal being made by h~at sealing along a line 30 extend-ing about the eight unit~ within the chamber, the line being discon~inued at some places so as ~o provide at least one opening 31 between top film 16 and bottom fi~m 13.
.
I~ Altho~gh weprefer that the films be sealed as above mentioned, after the ~acuum has been drawn, it is also possible to par~ially seal the fi~ms along line 30 and then open the lines 22 and 23 to draw the ~acuum.
Af~er the drawing Df ~acuum through lines 22 and 23 and the partial seal has bee~ made, the gas lines 27 and 28 are opened.
.
Referring again to Figs. 5 to 9, the gas line 28 -leads to ~he center orifices 29 in the ma~rices and provide passageæ which lead from ~he ouree of the gas to ~he gas orifices 29 ~ust below the slits 20. Gas introducet through these passages is forced upwardly through the slits 20 i~to the enclosure provided by the partial ~eal. Gas may escape from theenclosure through the opening 31. Gas also is introduced ints the head through the passage provided by line 27. We prefer that the pressure of ~he gas introdueed through the slit ~to the enclosure be somewhat greater ~han 3~797 that of the gas surrounding the enclosure within the chamber so tha~ the tPndency will be for gas to flow out-wardly through opening 31 from the enclo~ure rather than inwardly in o the enclosure.
We use the term "gas" to include air as ~ell as othex gases. The gas which is introduced into ~che chamber may be nitrogen or some other gas not harm~ul to the food and which is substantially free of oxygen.
After the pressure of the gas introduced into chamber D reache~ a pre~sure which is approximately that of the atmosphere about the cham~er, the lower section 21 may be lowered to open the chamber. The term "appro~i-mately" is meant to allow for some difference of pressures between the outs~de and inside o~ the chamber while still permitting the chamber to be~ opened without difieulty.
Weprefer that the gas be introduced to create a small posi-tive pressure within the chamber prior to opening the chxm-ber. This tends to preven~ flow of air into the chamber - when it is opened.
The next advance of the films passes the web which is formed in ehæmber ~ to section E. As the films move toward their position in section E, they move along over the bed 32 with the nozzles 33 (se~ Fig. 10) rîding under the film 13 un~il the sli~s c~me into contact with the nozzles: at which time ~he noæzles begin to push into the sl~ts turning the side edges upwardly and spreading them apart. When the slits come completely into register with the nozzle~, the nozzle has been inser~ed into the package as schem~tically illustrated in Fig. 12.
~7 37~
The nozzles 33 are provided with the internal passages 35. Tha~e passages are connected with the gas line 34, and when ~he web is advanced into i~s position where the nozzles are directly under the slits, the gas line is opened and the substantially oxygen~free ~as passe~
through line 34 and passages 35 into the package being formed between the ~op film 16 and the bottom film 13 and within the line of seal 30. This causes the pressure within ~he line of seal 30 to be somewhat hlgher tha~ outside this D line of seal so that the gas pas~es ou~ through the openings 31 so as ~o flush the package with oxygen.-free gas.
Then after the chamber F is opened, the film web is again ad~anced ~o move the section of the web whi h has just been flushed wîth gas into cha~ber F, and this chamber i~ again closed.
Chamber F may be constructed identical~y wi~h chamber D e~cep~ that ~he sealing mechanism within this chaIIiber is` arra~ged to seal the packages individually along closed` l~nes of seal betwee~ the top and bottom films 13 and 16 and excluding the slits 20.
Following closure of chamber F the vacuum is dra~n by opening lines 38 Ieadirlg rom the orifice~ in the matrices u~der the ~lits, and also by opening line 4û lead-ing from the head of ~han~ber F.
~ hile t~e chamber F i5 under the reduced preq-sure, the sealing mechanism is actuated and the web is completely sealed about line~ 41 enclosing each food unit arld excludîng ~he ~lit~ 20.
.. . . .
~C~737~7 Ater the vacuum i~ draw~ and the seal about lines 41 i~ made, these vacu~m lines 40 are closed and the gas, which may be air, is introduced into the cha~er F
through line 49 which may be a simple air ~alve. When the pressure within the chamber approximate~ the outside pressure, the chamber F is opened and the film web again ad~anced, this time to the section G.
.
The condition of the film web as it is.advanced from chamber F is illus~rated in Fig. 13. Note that ~he ~D top and bottom films are sealed about the line of seal 30 and the openings 31 which previously existed in the line of seal 30 are now closed by reason of the superimposed lines of seal efec~ed in ch~mber F and which,~in ehis embodiment~ embrace~ all eight food units:coneained in this sectioll of the film web. Alsc> the lines of seal 41 which e~tend individually about each food:unit e~clude the s lits 20.
An alternate procedure involves the back-filling of the packages with nitrogen or other substantially oxygen-- ,~ free gas prior to coDIpletely sealing the package in chamber F. According to this procedure, after a vacuum has been dr~wrl in chamber F, the vacuum lines are closed ~d a sub-stantially oxygen-free gas is introduced through line 44 and upwardly through slits 20 into the space be~ween the ~10-~, .
~73797 top and bottom films 16 and 13 and enclosed by the line of seal 30. The pres~ure of the gas so introduced is such as to fill this space to the extent deslred, after which the complete seal is made abou~ each individual unit, air then admitted to equalize approximately the pressures inside and outside th chamber and the chan~ber F then openad to permit advaneement of the web to the station G.
At station G the web is cu~ transver~ely by cut-ters 45 and 46 between the rows of sealed ~ood units, a~d then at the end of the machine the web is cut longitudinally by cutter 47 to separate the individual packages. Suit-ably the longitudinal cuts coincide with the ~lits 20 so tha~ the etge of the cut ~ilm is even and regular.
The above description explains a process with respect to what i~ done to a particular section of the web as ~his section moves sequentially through the process.
It should be understood that in accordance with the process diferent sections of the web are being acted upon simul-taneou ly in different parts of the apparatus. The lower parts of the chambers D and F and the strueture 50 which carries knives 19 may al~ be carried by a rail which i6 vertically m~vable so that ~hey~move up and down simul-t~neously in response ~o indexing ~echanism which also causes ~he advancem~nt of the film web while these par~s are in lowered posi~ion.
1~73'7~7 When the lower parts of chambers F and D and the knives 19 have been rai~ed, the~e two chambers are closed and the knives 19 malce sli~s ln the :~ilm at C.
Also this star~s a timed cycle at each o chambers D and F. At chamber D valves are opened to pull a vacuum; then the vacuum lines are r-losed and the sealing mechanism actua~ed to partially geal the web. Following this, gas lines are opened to admit oxyg~n-free gas into the chamber, then when substantial equalization of pressur occurs the ~0 gas lines are closed.
At th~ chamber F a timed cycle begins after closure o~ this chamber which first opens the vacuum lines from that chamber, then completely seals the film about the u~its indivldually. Alternately, this cycle may be ex~ended ~o a~mit oxygen-free gas prior to the sealing event.
At station E a cycle may be operated to turn on the gas when the web Qection reaches its position in this area, and to turn off the gas again when th film web is moved from this position or pref2rably, the gas may be left on continuously during the operation of the machine.
At station G a cycle may be started when a web ~ection reaches i~s position ~t this tation to operate the transverse cutters 45 and 46. The cutter 47 may oper-ate continuously to sever the web as it is advanced.
The inter~ittent movement of the rail to raise 1 0 ~ 3 7~ 7 and lower the lower parts of the chamber ~nd the structure carrying knives 19, and the timing o~ e~ents in each cycle may be operated by hand but pre~rably by mechanisms know~
to the ar~. Sui~ablyJ this may be done by the operation of motor driven c~ms or may be done by utilizing elec~ronic timing apparatus. Similarly, the e~ents in each of ~he cycles which take place a~ D, E and F may be timed and actuated by mechanical mean~ using cams or by known elec-tronic timing devices. It is, of course, necessary that ~0 the timin~ cycle at each position be completed before the chambers are opened.
As is set forth in this specification under "Background", a typical 2-ounce unit of meat consisting of a pair of bologna slices could be vacuum packed in film according to the prior practice to:provide a package hav-ing an oxygen concentration of 20% and a total volume of 0.125 to 0.264 cc o oxygen still contained in the package and having a shelf life of from 30 to 60 days.
We find that by using the improvemen~s ~e~ forth herein we can~reduce the total oxygen conten~ of the typical film-enclosed package of meat such as just referred to above to an amount less than 1/3 of that which it normally contained accordi~g to the prior practice. I am able by reason of the improvements herein described to obta~n ~uch a package having an oxygen concentration of less ~han 1 to 2% and a total ~olume of oxygen of 0.034 to 0.071 cc and a shelf life of from about 90 to 360 days depending on ~he type of product packaged. Such a change in ~helf life in 1~ ~379 7 a meat product gives a very substantial advantage in the distribution and marketing of meat or other food items.
There are several features about our process to which we attribute this improvementO ~e believe that our process is substantially more effective in remo~ring oxygen particularly from the spaces be~ween the slices and within the me t itself.
A fea~ure of the process which is believed to contribute to the improvements i5 the use of two chamb rs into which the package is successively passed as the pack-age is formed whereby a vacuum may be drawn in the first of the chambers and back~filled with a~ oxygen-free gas, and then vacuumized and sealed in the second chamber.
Another feature is the flushing of the partially-formed package whi~e it is in a position~be~ween the two cham- .
bers wi~h a substantially oxygen-free gas. Yet another~ -featu~e is the use of gas lines for admitting gas into the partially formed package which are separate rom the vacuum lines uged to withdraw gas from the chamber whereby the oxygen contained in ~he withdrawal lines is no~ pa~sed back into the package when gas is introduced as was pre-viously ~the practice Annther feature lies in ~he use of a gas for back-filling the package as lt is being formed which gas itself has a low content of oxygen. The prior practice has been to use a gas such as nitrogen c~ibined wi~h from 50 to 90% of C02. In our process we pre~er to use either ~L~73797 nitrogen or other substantially oxygen-free gas by itself or use such a gas combined with not more than 2 to lQ% of co2. This provides the advantages of having the Cû2 pre-sent without the disadvantage o significan~ly increasing the concentration of oxygen.
Yet another feature is the injectîon of substan-tially oxyge~-free gas in the for~ of a jet through a slit in the lower film, and ano~her ea~ure is ~hat of locating openings to the vacuum lines below the slit in the lower film so that the side ~dges of the slit are drawn down to enlarge ~he opening provided by the jet and ~acilitate the introduc~ion of gas into the package being formed.
Anoth~r feature is the use of the special nozzle which rid~s under the bottom film until a slit is advanced to a position over the nozzle and be~een the two cha~bers where it then serves to turn up the edges of the slit and provide arl effective way to introduce the oxygen-free gas a~ the station where flushing takes place. Also, other features not above re~erred to wiIl be found which also ~en~e in producing Jche results achieved by this inven~ion.
While only one embodiment of the. invention together with certain ~ariations therein has been describ~d in de~ail, it will be apparent to those skilled in this art that many changes may be made and the invention practiced in m~ny particular ways, all within the spirit of the invention and within the scope of the appended claims.
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i3 advanced. The slits cut in fllm 16 may va~y in siæe.
Ordlnarily they may be of 1:he order of 2 or 3 inchec in.
length but in the cases oi~ larger-sized food units, the sizes of the slits may be increa~ed.
.. . ..
1C~73791'7 The next advance of film 13 brings th~ two rows of food uni~s to a position between the uni~s C and D and the following ad~rance brings these same units into the ~irst chamber D, the lower section 21 of which is then in lowered position to open the chamber and permit the movement of the films together with the eight ~ood units into the chamber.
Then the section 21 is raised ~o close the cham-ber D, providing an airtight closure. The ~acuum lines 22 and ~3 are then opened. Line 22 leads from the h~ad of chamber D and line 23 leads from a pos1tion below the film 13. In this wa~ the vacuum o~ about 29 or 29~1/2 inches of mercury may be drawn in the chamber. Air is also drawn from t~e ~ood units through the slits and this air with-drawn ~hrough lines 23.
A~ thi~ point reference is made ~o Figs. S and 9. As the food uni~s and film come to the prescribed posi-tion within chamber D, s~ts in ~ilm 13 are immediately over a matrix 24 (Fig. 6) con~aining orifices 25. Orifices 25 are connected with line 23 to provide passages leading from below the slits to the source of the vacuum. A trough 26 having V-shaped~sides is provided in the top of this matrix. This tr~ugh is aligned with the slit in the film 13 t~ereabove and the orifices 25 are in th~ bottom of this trough.
When the vacuum is applied through passages in lines 23 air is withdrawn through ~lits 20 and the edges 1C~73797 of the sli~ 23a and 23b are drawn down against the inter-ior side of trough 26 (see Fig. 9) so as to enlarge the opening pravided by the ~lits.
After the vac~um ha~ been drawn, a partial seal is made bet:ween the top and bottom films within cha~ber D, the seal being made by h~at sealing along a line 30 extend-ing about the eight unit~ within the chamber, the line being discon~inued at some places so as ~o provide at least one opening 31 between top film 16 and bottom fi~m 13.
.
I~ Altho~gh weprefer that the films be sealed as above mentioned, after the ~acuum has been drawn, it is also possible to par~ially seal the fi~ms along line 30 and then open the lines 22 and 23 to draw the ~acuum.
Af~er the drawing Df ~acuum through lines 22 and 23 and the partial seal has bee~ made, the gas lines 27 and 28 are opened.
.
Referring again to Figs. 5 to 9, the gas line 28 -leads to ~he center orifices 29 in the ma~rices and provide passageæ which lead from ~he ouree of the gas to ~he gas orifices 29 ~ust below the slits 20. Gas introducet through these passages is forced upwardly through the slits 20 i~to the enclosure provided by the partial ~eal. Gas may escape from theenclosure through the opening 31. Gas also is introduced ints the head through the passage provided by line 27. We prefer that the pressure of ~he gas introdueed through the slit ~to the enclosure be somewhat greater ~han 3~797 that of the gas surrounding the enclosure within the chamber so tha~ the tPndency will be for gas to flow out-wardly through opening 31 from the enclo~ure rather than inwardly in o the enclosure.
We use the term "gas" to include air as ~ell as othex gases. The gas which is introduced into ~che chamber may be nitrogen or some other gas not harm~ul to the food and which is substantially free of oxygen.
After the pressure of the gas introduced into chamber D reache~ a pre~sure which is approximately that of the atmosphere about the cham~er, the lower section 21 may be lowered to open the chamber. The term "appro~i-mately" is meant to allow for some difference of pressures between the outs~de and inside o~ the chamber while still permitting the chamber to be~ opened without difieulty.
Weprefer that the gas be introduced to create a small posi-tive pressure within the chamber prior to opening the chxm-ber. This tends to preven~ flow of air into the chamber - when it is opened.
The next advance of the films passes the web which is formed in ehæmber ~ to section E. As the films move toward their position in section E, they move along over the bed 32 with the nozzles 33 (se~ Fig. 10) rîding under the film 13 un~il the sli~s c~me into contact with the nozzles: at which time ~he noæzles begin to push into the sl~ts turning the side edges upwardly and spreading them apart. When the slits come completely into register with the nozzle~, the nozzle has been inser~ed into the package as schem~tically illustrated in Fig. 12.
~7 37~
The nozzles 33 are provided with the internal passages 35. Tha~e passages are connected with the gas line 34, and when ~he web is advanced into i~s position where the nozzles are directly under the slits, the gas line is opened and the substantially oxygen~free ~as passe~
through line 34 and passages 35 into the package being formed between the ~op film 16 and the bottom film 13 and within the line of seal 30. This causes the pressure within ~he line of seal 30 to be somewhat hlgher tha~ outside this D line of seal so that the gas pas~es ou~ through the openings 31 so as ~o flush the package with oxygen.-free gas.
Then after the chamber F is opened, the film web is again ad~anced ~o move the section of the web whi h has just been flushed wîth gas into cha~ber F, and this chamber i~ again closed.
Chamber F may be constructed identical~y wi~h chamber D e~cep~ that ~he sealing mechanism within this chaIIiber is` arra~ged to seal the packages individually along closed` l~nes of seal betwee~ the top and bottom films 13 and 16 and excluding the slits 20.
Following closure of chamber F the vacuum is dra~n by opening lines 38 Ieadirlg rom the orifice~ in the matrices u~der the ~lits, and also by opening line 4û lead-ing from the head of ~han~ber F.
~ hile t~e chamber F i5 under the reduced preq-sure, the sealing mechanism is actuated and the web is completely sealed about line~ 41 enclosing each food unit arld excludîng ~he ~lit~ 20.
.. . . .
~C~737~7 Ater the vacuum i~ draw~ and the seal about lines 41 i~ made, these vacu~m lines 40 are closed and the gas, which may be air, is introduced into the cha~er F
through line 49 which may be a simple air ~alve. When the pressure within the chamber approximate~ the outside pressure, the chamber F is opened and the film web again ad~anced, this time to the section G.
.
The condition of the film web as it is.advanced from chamber F is illus~rated in Fig. 13. Note that ~he ~D top and bottom films are sealed about the line of seal 30 and the openings 31 which previously existed in the line of seal 30 are now closed by reason of the superimposed lines of seal efec~ed in ch~mber F and which,~in ehis embodiment~ embrace~ all eight food units:coneained in this sectioll of the film web. Alsc> the lines of seal 41 which e~tend individually about each food:unit e~clude the s lits 20.
An alternate procedure involves the back-filling of the packages with nitrogen or other substantially oxygen-- ,~ free gas prior to coDIpletely sealing the package in chamber F. According to this procedure, after a vacuum has been dr~wrl in chamber F, the vacuum lines are closed ~d a sub-stantially oxygen-free gas is introduced through line 44 and upwardly through slits 20 into the space be~ween the ~10-~, .
~73797 top and bottom films 16 and 13 and enclosed by the line of seal 30. The pres~ure of the gas so introduced is such as to fill this space to the extent deslred, after which the complete seal is made abou~ each individual unit, air then admitted to equalize approximately the pressures inside and outside th chamber and the chan~ber F then openad to permit advaneement of the web to the station G.
At station G the web is cu~ transver~ely by cut-ters 45 and 46 between the rows of sealed ~ood units, a~d then at the end of the machine the web is cut longitudinally by cutter 47 to separate the individual packages. Suit-ably the longitudinal cuts coincide with the ~lits 20 so tha~ the etge of the cut ~ilm is even and regular.
The above description explains a process with respect to what i~ done to a particular section of the web as ~his section moves sequentially through the process.
It should be understood that in accordance with the process diferent sections of the web are being acted upon simul-taneou ly in different parts of the apparatus. The lower parts of the chambers D and F and the strueture 50 which carries knives 19 may al~ be carried by a rail which i6 vertically m~vable so that ~hey~move up and down simul-t~neously in response ~o indexing ~echanism which also causes ~he advancem~nt of the film web while these par~s are in lowered posi~ion.
1~73'7~7 When the lower parts of chambers F and D and the knives 19 have been rai~ed, the~e two chambers are closed and the knives 19 malce sli~s ln the :~ilm at C.
Also this star~s a timed cycle at each o chambers D and F. At chamber D valves are opened to pull a vacuum; then the vacuum lines are r-losed and the sealing mechanism actua~ed to partially geal the web. Following this, gas lines are opened to admit oxyg~n-free gas into the chamber, then when substantial equalization of pressur occurs the ~0 gas lines are closed.
At th~ chamber F a timed cycle begins after closure o~ this chamber which first opens the vacuum lines from that chamber, then completely seals the film about the u~its indivldually. Alternately, this cycle may be ex~ended ~o a~mit oxygen-free gas prior to the sealing event.
At station E a cycle may be operated to turn on the gas when the web Qection reaches its position in this area, and to turn off the gas again when th film web is moved from this position or pref2rably, the gas may be left on continuously during the operation of the machine.
At station G a cycle may be started when a web ~ection reaches i~s position ~t this tation to operate the transverse cutters 45 and 46. The cutter 47 may oper-ate continuously to sever the web as it is advanced.
The inter~ittent movement of the rail to raise 1 0 ~ 3 7~ 7 and lower the lower parts of the chamber ~nd the structure carrying knives 19, and the timing o~ e~ents in each cycle may be operated by hand but pre~rably by mechanisms know~
to the ar~. Sui~ablyJ this may be done by the operation of motor driven c~ms or may be done by utilizing elec~ronic timing apparatus. Similarly, the e~ents in each of ~he cycles which take place a~ D, E and F may be timed and actuated by mechanical mean~ using cams or by known elec-tronic timing devices. It is, of course, necessary that ~0 the timin~ cycle at each position be completed before the chambers are opened.
As is set forth in this specification under "Background", a typical 2-ounce unit of meat consisting of a pair of bologna slices could be vacuum packed in film according to the prior practice to:provide a package hav-ing an oxygen concentration of 20% and a total volume of 0.125 to 0.264 cc o oxygen still contained in the package and having a shelf life of from 30 to 60 days.
We find that by using the improvemen~s ~e~ forth herein we can~reduce the total oxygen conten~ of the typical film-enclosed package of meat such as just referred to above to an amount less than 1/3 of that which it normally contained accordi~g to the prior practice. I am able by reason of the improvements herein described to obta~n ~uch a package having an oxygen concentration of less ~han 1 to 2% and a total ~olume of oxygen of 0.034 to 0.071 cc and a shelf life of from about 90 to 360 days depending on ~he type of product packaged. Such a change in ~helf life in 1~ ~379 7 a meat product gives a very substantial advantage in the distribution and marketing of meat or other food items.
There are several features about our process to which we attribute this improvementO ~e believe that our process is substantially more effective in remo~ring oxygen particularly from the spaces be~ween the slices and within the me t itself.
A fea~ure of the process which is believed to contribute to the improvements i5 the use of two chamb rs into which the package is successively passed as the pack-age is formed whereby a vacuum may be drawn in the first of the chambers and back~filled with a~ oxygen-free gas, and then vacuumized and sealed in the second chamber.
Another feature is the flushing of the partially-formed package whi~e it is in a position~be~ween the two cham- .
bers wi~h a substantially oxygen-free gas. Yet another~ -featu~e is the use of gas lines for admitting gas into the partially formed package which are separate rom the vacuum lines uged to withdraw gas from the chamber whereby the oxygen contained in ~he withdrawal lines is no~ pa~sed back into the package when gas is introduced as was pre-viously ~the practice Annther feature lies in ~he use of a gas for back-filling the package as lt is being formed which gas itself has a low content of oxygen. The prior practice has been to use a gas such as nitrogen c~ibined wi~h from 50 to 90% of C02. In our process we pre~er to use either ~L~73797 nitrogen or other substantially oxygen-free gas by itself or use such a gas combined with not more than 2 to lQ% of co2. This provides the advantages of having the Cû2 pre-sent without the disadvantage o significan~ly increasing the concentration of oxygen.
Yet another feature is the injectîon of substan-tially oxyge~-free gas in the for~ of a jet through a slit in the lower film, and ano~her ea~ure is ~hat of locating openings to the vacuum lines below the slit in the lower film so that the side ~dges of the slit are drawn down to enlarge ~he opening provided by the jet and ~acilitate the introduc~ion of gas into the package being formed.
Anoth~r feature is the use of the special nozzle which rid~s under the bottom film until a slit is advanced to a position over the nozzle and be~een the two cha~bers where it then serves to turn up the edges of the slit and provide arl effective way to introduce the oxygen-free gas a~ the station where flushing takes place. Also, other features not above re~erred to wiIl be found which also ~en~e in producing Jche results achieved by this inven~ion.
While only one embodiment of the. invention together with certain ~ariations therein has been describ~d in de~ail, it will be apparent to those skilled in this art that many changes may be made and the invention practiced in m~ny particular ways, all within the spirit of the invention and within the scope of the appended claims.
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Claims (48)
1. A process for packaging foods comprising passing a bottom film with a unit of food thereon into an open first chamber, closing said first chamber with said film and unit therein, drawing air through a passage leading from said first chamber to reduce air pressure within said first chamber, closing said passage, introduc-ing into said first chamber a gas which is substantially free of oxygen whereby said introduced gas takes the place of air which is removed from said first chamber to bring the pressure within said first chamber to approximately that of the atmosphere surrounding said first chamber, opening said first chamber, passing said film and food unit out of said first chamber, passing said food unit with said bottom film beneath and a top film above said unit into an open second chamber, closing said second chamber 9 withdrawing gas from a passage leading from said second chamber to reduce the pressure within said second chamber, and sealing said top and bottom films together along a line extending about said unit.
2. A process as set forth in claim 1 including the added steps of introducing a gas into said second cham-ber to bring the pressure within said second chamber to approximately that of the atmosphere surrounding said second chamber, opening said second chamber, and passing said unit enclosed by said top and bottom films out of said second chamber.
3. A process as set forth in claim 1 in which said gas which is substantially free of oxygen is intro-duced into said first chamber through a passage which leads to said first chamber and which is separate from said passage leading from said first chamber.
4. A process for packaging foods comprising passing a bottom film with a unit of food thereon into an open first chamber, closing said first chamber with said film and unit therein, drawing air through a passage lead-ing from said first chamber to reduce air pressure within said chamber, closing said passage, introducing into said first chamber a gas which is substantially free of oxygen whereby said introduced gas takes the place of air which is removed from said first chamber to bring the pressure within said first chamber to approximately that of the atmosphere surrounding said first chamber, opening said first chamber, passing said film and food unit out of said first chamber, passing said food with said bottom film beneath and a top film above said unit into an open second chamber, closing said second chamber, withdrawing gas from a passage leading from said second chamber to reduce the pressure within said second chamber, introducing a gas sub-stantially free of oxygen into said second chamber, and sealing said top and bottom film along a line about said unit.
5. A process as set forth in claim 4 including the steps of introducing into said second chamber sufficient gas to bring the pressure within said second chamber to approximately that of the atmosphere surrounding said second chamber, opening said second chamber, and passing said unit enclosed by said top and bottom films out of said second chamber.
6. A process as set forth in claim 1 in which a top film is over said unit when said unit is passed into said first chamber.
7. A process as set forth in claim 6 wherein said bottom film has an opening therein and wherein at least a part of said gas introduced into said first cham-ber is passed upwardly through said opening.
8. A process as set forth in claim 6 which includes sealing said top and bottom films along a line extending about said unit except for one or more spaces to provide a partial seal whereby to leave openings between said films: through which gas may escape from the film n-closure about the unit and thereafter introducing gas through said opening.
9. A process as set forth in claim 8 in which said opening is a slit located to one side of said unit and within said line and in which said passage leading from said first chamber leads from a position adjacent said slit whereby air from said unit is drawn through said slit and into said passage.
10. A process as set forth in claim 9 in which said passage leading from said first chamber opens at a position below said slit whereby gas from said passage leading into said first chamber is passed upwardly through said slit.
11. A process as set forth in claim 9 including drawing the edges of said slit downwardly by the passage of air through said s lit to enlarge the area of the open-ing provided by said slit.
12. A process as set forth in claim 11 in which a trough aligned with said slit is provided beneath said slit and wherein the sides of said slit are drawn down onto the inner sides of said trough.
13. A process as set forth in claim 8 in which a plurality of spaced food units are placed on said bottom film and in which said top film is over each of said units.
14. A process as set forth in claim 13 in which said opening is a slit located between said units and in which said line extends about all of said units and about said slit.
15. A process as set forth in claim 14 in which said bottom film includes a plurality of said slits each within said line and which includes a plurality of passages leading from said first chamber each of which leads from a position adjacent one of said slits, and which includes a plurality of said passages leading from said first chamber, each of said passages leading to said first chamber having an opening which opens at a position below said slit where-by air from said units is drawn through each of said slits and into said passages leading from said chamber and gas is passed from said passages leading into said chamber and through each of said slits.
16. A process as set forth in claim 15 wherein said plurality of said units partially sealed between said top and bottom films is passed into said second chamber and wherein the sealing of said films is about each unit individually, the line of seal about each unit excluding the slits in said bottom film.
17. A process as set forth in claim 6 which includes sealing said top and bottom films in said first chamber along a line extending about said unit except for one or more spaces to provide a partial seal whereby to leave openings between said films through which gas may escape from the film enclosure about the unit, and there-after introducing gas through said opening, and which in-cludes sealing said top and bottom films along a line ex-tending about said unit but excluding said opening.
18. A process as set forth in claim 4 in which said top film is placed over said unit before said unit is passed into said first chamber.
19. A process as set forth in claim 18 wherein said bottom film has an opening therein and wherein at least a part of said gas introduced into each of said chambers is passed upwardly through said opening.
20. A process as set forth in claim 18 which includes sealing said top and bottom films along a line extending about said unit except for one or more spaces to provide a partial seal whereby to leave openings be-tween said films through which gas may escape from the film enclosure about the unit and thereafter introducing gas through said opening.
21. A process as set forth in claim 20 in which said opening is a slit located to one side of said unit and within said line and in which said passage leading from said first chamber leads from a position adjacent said slit whereby air from said unit is drawn through said slit and into said passage.
22. A process as set forth in claim 21 in which said passage leading from said first chamber opens at a posi-tion below said slit whereby gas leading into said first chamber is passed upwardly through said slit.
23. A process as set forth in claim 8 in which said unit enclosed by said top and bottom films and par-tially sealed is passed from said first chamber to an inter-mediate position in which a nozzle engages said opening, and including passing gas which is substantially free of oxygen through said nozzle and through said opening into the enclosure between said films and within said line of partial sealing, whereby said gas passed into said enclo-sure passes out through said opening provided by said par-tial sealing to flush the enclosure with said gas which is substantially oxygen-free, and passing the flushed unit enclosed within said films into said second chamber.
24. A process as set forth in claim 20 in which said unit enclosed by said top and bottom films and par-tially sealed is passed from said first chamber to an in-termediate position in which a nozzle engages said open-ing, and including passing gas which is substantially free of oxygen through said nozzle and said opening into the enclosure between said films and within said line of par-tial sealing, whereby said gas passed into said enclosure passes out through said openings provided by said partial sealing to flush the enclosure with said gas which is sub-stantially oxygen-free, and passing the flushed unit en-closed within said films into said second chamber.
25. A process as set forth in claim 20 which includes sealing said top and bottom films in said first chamber along a line extending about said unit except for one or more places to provide a partial seal whereby to leave openings between said films through which gas may escape from the film enclosure about the unit, and there-after introducing gas through said opening, and which includes sealing said cop and bottom films along a line extending about said unit but excluding said opening.
26. A process for packaging foods comprising passing a unit of food between a top film and a bottom film into an open first chamber, said bottom film having an opening therein to one side of said unit, withdrawing air from said first chamber through a passage which is open at a position below said opening, whereby pressure within said chamber is reduced, sealing said top and bot-tom films along a line which extends about said unit and encloses said opening, introducing a gas which is sub-stantially free of oxygen through a passage which opens at a position under said opening whereby to pass said gas upwardly through said opening and into the enclosure be-between said films and to bring the pressure within said chamber to approximately that of the atmosphere surround-ing said chamber, opening said chamber, passing said unit with said enclosure out of said chamber to a position in which a nozzle engages said opening passing gas which is substantially free of oxygen through said nozzle and into said enclosure to flush said enclosure, passing said unit which has been flushed within said enclosure into an open second chamber, closing said second chamber, withdrawing gas from said second chamber through an outlet passage which is open at a position under said opening to draw gas through said opening and out of said second chamber through said outlet passage, and sealing said top and bottom films along a line extending about said unit and excluding said opening.
27. A process for packaging foods comprising passing a unit of food between a top film and a bottom film into an open first chamber, said bottom film having an opening therein to one side of said unit, withdrawing air from said first chamber through a passage which is open at a position below said opening, whereby pressure within said chamber is reduced, sealing said top and bottom films along a line which extends about said unit and encloses said opening, introducing a gas which is substantially free of oxygen through a passage which opens at a position under said opening whereby to pass said gas upwardly through said opening and into the enclosure between said films and to bring the pressure within said chamber to approximately that of the atmosphere surrounding said chamber, opening said chamber,passing said unit within said enclosure out of said chamber to a position in which a nozzle engages said opening, passing gas which is substantially free of oxygen through said nozzle and into said enclosure to flush said enclosure, passing said unit which has been flushed within said enclosure into an open second chamber, closing said second chamber, withdrawing gas from said second chamber through an outlet passage which is open at a position under said opening to draw gas through said opening and out of said second chamber through said outlet passage, passing gas which is substantially free of oxygen through a passage into said second chamber to a position below said opening whereby gas is passed upwardly through said opening into the enclosure between said top and bottom films, and sealing said top and bottom films along a line extending about said unit and excluding said opening.
28. A process as set forth in claim 2 in which a plurality of units is passed consecutively into and out of said first chamber and then into and out of said second chamber and including the steps of simultaneously opening and closing said chambers.
29. A process as set forth in claim 5 wherein a plurality of units are passed consecutively into and out of said first chamber and then into and out of said second chamber, and including the steps of simultaneously opening and closing said chambers.
30. A process as set forth in claim 1 in which said gas is nitrogen containing from 2 to 10% of carbon-dioxide.
31. A process for packaging foods comprising passing a bottom film with a unit of food thereon into a first chamber;
drawing a vacuum in said first chamber;
backfilling said first chamber with a gas which is substantially free of oxygen until the pressure within said chamber is substantially that which surrounds said first chamber;
passing said bottom film and food unit out of said first chamber;
passing said food unit with said bottom film beneath and a top film above said food unit into a second chamber, drawing a vacuum in said second chamber; and sealing said top and bottom films together about said food unit while still in said second chamber.
drawing a vacuum in said first chamber;
backfilling said first chamber with a gas which is substantially free of oxygen until the pressure within said chamber is substantially that which surrounds said first chamber;
passing said bottom film and food unit out of said first chamber;
passing said food unit with said bottom film beneath and a top film above said food unit into a second chamber, drawing a vacuum in said second chamber; and sealing said top and bottom films together about said food unit while still in said second chamber.
32. A process for packaging foods comprising passing a bottom film with a unit of food thereon into an open first chamber, closing said first chamber with said film and unit therein, drawing air through a passage leading from said first chamber to reduce air pressure within said first chamber and to reduce the amount of oxygen about said food unit, closing said passage, introducing into said first chamber a gas which is substantially free of oxygen until the pressure within said first chamber is approximately that of the atmosphere surround-ing said first chamber, opening said first chamber, passing said film and food unit out of said first chamber, passing said food unit with said bottom film beneath and a top film above said unit into an open second chamber, closing said second cham-ber, then withdrawing gas through a passage leading from said second chamber to reduce the pressure within said second cham-ber and to further reduce the amount of oxygen about said food, sealing said top and bottom films together along a line extend-ing about said unit, and passing substantially oxygen-free gas between said top and bottom film after the film and food unit has left said first chamber and before it has entered said second chamber to flush the area about said unit with substantially oxygen-free gas.
33. In a process for packaging foods wherein a unit of food on a bottom film is passed into a first chamber, a vacuum drawn in said first chamber and said first chamber backfilled with a gas which is substantially free of oxygen until the pressure within said chamber is substantially that which surrounds the first chamber, said bottom film and food unit being passed out of said first chamber, said food unit while between said bottom film and a top film being passed into a second chamber, and a vacuum drawn in said second chamber, said films being sealed together about said food unit while within said second chamber, the improvement which includes flushing said food unit with a gas which is substantially free of oxygen after said food unit has left said first chamber and before it enters said second chamber.
34. A process as set forth in claim 33 including the steps of slitting said bottom film to form a slit at a place to one side of said food unit and passing said gas through said slit and into contact with said food unit to flush said food unit.
35. A process as set forth in claim 34 which in-cludes discharging said gas through a nozzle located between said chambers when said bottom film is passed to a position in which said slit is in register with said nozzle.
36. A process as set forth in claim 34 including the steps of partially sealing said top and bottom films about said unit to thereby form an enclosure for said food unit and said slit and leave an opening through which said gas may escape from said enclosure.
37. A process as defined in claim 31, said bottom film having a slit therein to one side of said food unit and wherein said gas is back filled into said first chamber and through said slit.
38. A process as set forth in claim 37 in which said food unit is passed into said chamber between said bottom film and said top film.
39. A process as set forth in claim 38 which in-cludes partially sealing said top and bottom film about said food unit and said slit but leaving an opening in the seal so formed, said partial sealing step being done prior to passing said gas through said slit to thereby form an enclosure about said food unit, whereby said gas passed through said slit may flush said food unit within said enclosure and pass out of said enclosure through said opening.
40. A process as set forth in claim 37 in which said gas is passed from beneath said bottom film upwardly.
through said slit in the form of a jet.
through said slit in the form of a jet.
41. A process as set forth in claim 40which in-cludes the step of withdrawing air from a position below said slit to thereby draw downwardly the lips of said slit to thereby provide a widened opening, said withdrawl being done prior to introduction of said gas through said opening.
42. In a process for packaging foods as defined in claim 31 and in which said food unit between said top film and said bottom film is flushed with a gas which is substan-tially free of oxygen, said process further including the steps of slitting said bottom film to form a slit therein, moving said food unit between said top and bottom films over a bed having a nozzle projecting upwardly of said bed whereby said bottom film rides over said nozzle until said slit comes into register with said nozzle and said nozzle enters said slit, and while said nozzle is in engagement with said slit discharging said gas upwardly through said nozzle and about said food unit between said films.
43. A process as set forth in claim 42 including the step of partially sealing said top and bottom films about said food unit and said slit while leaving an opening through the seal through which gas from about the food unit may escape, said partial sealing step being done prior to said step of discharging gas upwardly through said nozzle and about said food unit.
44. A process as set forth in claim 42 in which said nozzle is elongated in a direction aligned with the direction of movement of said bottom film and has downwardly inclined surfaces from a central portion toward said bed to thereby facilitate movement of said nozzle into and out of said slit as said bottom film is passed along said bed.
45. A process as set forth in claim 44 wherein said gas is discharged upwardly through a passage in said central portion of said nozzle.
46. A process as set forth in claim 42 including the step of moving said food unit along said bed after dis-charging gas through said nozzle and about said food unit to move said slit out of register with said nozzle whereby said bottom film again rides on said nozzle.
47. A process as set forth in claim 42 in which said gas is discharged into the area enclosed by said partial seal and is permitted to pass from said area through said opening and including the step of sealing said top and bottom films about said food unit excluding said slit.
48. In a process for packaging foods comprising passing a unit of food while between a top film and a bottom film having a slit therein into an open first chamber, closing said first chamber with said film and unit therein, drawing air through a passage leading from said first chamber to re-
48. In a process for packaging foods comprising passing a unit of food while between a top film and a bottom film having a slit therein into an open first chamber, closing said first chamber with said film and unit therein, drawing air through a passage leading from said first chamber to re-
claim 48 continued.
duce air pressure within the said first chamber and to reduce the amount of oxygen about said food unit, closing said passage, introducing into said first chamber a gas which is substantially free of oxygen until the pressure within said first chamber is approximately that of the atmosphere surrounding said first chamber is approximately that of the atmosphere surrounding said first chamber, while said food unit is in said first chamber between said top and bottom films sealing said top and bottom films along a line extending about said unit except for one or more spaces to provide a partial seal whereby to leave an opening between said films through which gas may escape from the film enclosure about said unit, when the pressure within said first chamber is substantially that of the surrounding atmosphere opening said first chamber, passing said unit enclosed by said top and bottom films from said first chamber to an intermediate position in which a nozzle engages said slit, passing gas which is substantially free of oxygen through said nozzle and through said slit into the enclosure between said films and within said line of partial sealing whereby gas passed into said enclosure may pass out through said opening provided by partial sealing to flush the enclosure with said gas, passing said food unit with said bottom film beneath and a top film above said unit into an open second chamber, closing said second chamber, then withdrawing gas from a passage leading from said second chamber to reduce the pressure within said second chamber and to further reduce the amount of oxygen about said food, and thereafter sealing said top and bottom films together along a line extending about said unit.
duce air pressure within the said first chamber and to reduce the amount of oxygen about said food unit, closing said passage, introducing into said first chamber a gas which is substantially free of oxygen until the pressure within said first chamber is approximately that of the atmosphere surrounding said first chamber is approximately that of the atmosphere surrounding said first chamber, while said food unit is in said first chamber between said top and bottom films sealing said top and bottom films along a line extending about said unit except for one or more spaces to provide a partial seal whereby to leave an opening between said films through which gas may escape from the film enclosure about said unit, when the pressure within said first chamber is substantially that of the surrounding atmosphere opening said first chamber, passing said unit enclosed by said top and bottom films from said first chamber to an intermediate position in which a nozzle engages said slit, passing gas which is substantially free of oxygen through said nozzle and through said slit into the enclosure between said films and within said line of partial sealing whereby gas passed into said enclosure may pass out through said opening provided by partial sealing to flush the enclosure with said gas, passing said food unit with said bottom film beneath and a top film above said unit into an open second chamber, closing said second chamber, then withdrawing gas from a passage leading from said second chamber to reduce the pressure within said second chamber and to further reduce the amount of oxygen about said food, and thereafter sealing said top and bottom films together along a line extending about said unit.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US56801675A | 1975-04-14 | 1975-04-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073797A true CA1073797A (en) | 1980-03-18 |
Family
ID=24269577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA248,939A Expired CA1073797A (en) | 1975-04-14 | 1976-03-26 | Process for packaging food |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS51125592A (en) |
| CA (1) | CA1073797A (en) |
| DE (1) | DE2613840A1 (en) |
| DK (1) | DK146676A (en) |
| FR (1) | FR2307704A1 (en) |
| GB (1) | GB1521563A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3625081A1 (en) * | 1986-07-24 | 1988-02-04 | Lieder Maschinenbau Gmbh & Co | METHOD AND DEVICE FOR THE PRESERVATION OF GOODS INCLUDED IN A CONTAINER |
| CN109436442B (en) * | 2018-10-31 | 2021-08-27 | 鲁东大学 | Full-automatic slice butter stripping and slicing laminating equipment |
-
1976
- 1976-03-26 CA CA248,939A patent/CA1073797A/en not_active Expired
- 1976-03-30 DK DK146676A patent/DK146676A/en not_active IP Right Cessation
- 1976-03-31 DE DE19762613840 patent/DE2613840A1/en active Pending
- 1976-04-13 FR FR7610851A patent/FR2307704A1/en not_active Withdrawn
- 1976-04-14 JP JP4232576A patent/JPS51125592A/en active Pending
- 1976-04-14 GB GB1523476A patent/GB1521563A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1521563A (en) | 1978-08-16 |
| DK146676A (en) | 1976-10-15 |
| JPS51125592A (en) | 1976-11-02 |
| DE2613840A1 (en) | 1976-10-28 |
| FR2307704A1 (en) | 1976-11-12 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |