US3910009A

US3910009A - Machine for establishing a controlled atmosphere in packages

Info

Publication number: US3910009A
Application number: US508982A
Authority: US
Inventors: Allen B Canfield
Original assignee: Rexham Corp
Current assignee: Kloeckner Bartelt Inc
Priority date: 1974-09-25
Filing date: 1974-09-25
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07

Abstract

Filled but unsealed pouches are automatically loaded into holders which then are lowered into chambers in a turret for step-by-step indexing through vacuum and gas stations where virtually all of the oxygen is removed from the pouches. Thereafter, the pouches are sealed in the presence of a nonoxidizing gas and then are indexed and raised upwardly out of the chambers preparatory to being automatically unloaded from the holders.

Description

United States Patent [191 7 Canfield Oct. 7, 1975 MACHINE FOR ESTABLISHING A 3,488,915 1/1970 Delestatius 53/112 A CONTROLLED ATMOSPHERE IN 3,508,373 4/1970 Robinson, Jr. 53/1 12 RX PACKAGES Allen B. Canfield, Rockford, Ill.

Assignee: Rexham Corporation, Rockford, Ill.

Filed: Sept. 25,1974

Appl. No.: 508,982

Inventor:

US. Cl 53/112 B; 53/95; 53/373 Int. Cl. B65B 31/02 Field of Search 53/86, 89, 95, 96, 110,

53/110 R, 110 A, '1 10 B, 183, 353, 373

References Cited UNITED STATES PATENTS 9/1963 Grafingholt 53/95 11/1965 Buchner 53/95 X 12/1969 Rausing et a1 53/112 BX Primary ExaminerRobert L. Spruill Assistant ExaminerLe0n Gilden Attorney, Agent, or Firm-Wolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[5 7 ABSTRACT Filled but unsealed pouches are automatically loaded into holders which then are lowered into chambers in a turret for step-by-step indexing through vacuum and gas stations where virtually all of the oxygen is removed from the pouches. Thereafter, the pouches are sealed in the presence of a non-oxidizing gas and then are indexed and raised upwardly out of the chambers preparatory to being automatically unloaded from the holders.

15 Claims, 14 Drawing Figures US. Patent (M11975 Sheet 1 of7 3,910,009

atent 0a. 7,1975 Sheet 2 of 7 3,910,009

atem

Get. 7,1975 Shegt 4 of 7 US. Patent 0m. 7,1975 Sheet 6 of7 3,910,009

Sheet 7 0f 7 3,910,009

Oct. 7,1975

US. Patent MACHINE FOR ESTABLISHING A CONTROLLED ATMOSPHERE IN PACKAGES BACKGROUND OF THE INVENTION This invention relates to a machine for establishing a non-oxidizing atmosphere in newly filled packages and for thereafter closing the open ends of the packages. Machines for performing these functions are disclosed in Bartelt US. Pat. No. 2,649,671; Johnson US. Pat. No. 3,619,975 and Schulze U.S. Pat. No. 3,708,952.

SUMMARY OF THE INVENTION The general aim of the present invention is to provide a new and improved machine which is capable of establishing in the packages an atmosphere having an extremely low oxygen content, the foregoing being achieved by subjecting the packages to several distinct oxygen purging operations after the packages have been filled and before the packages are closed.

A more detailed object is to provide a machine in which the newly filled packages are purged of oxygen at several stations as the packages are indexed step-bystep by a turret, the packages being carried within unique chambers in the turret and being both evacuated and filled with a non-oxidizing gas as the chambers are moved to different stations during indexing of the turret.

Another object of the invention is to provide novel holders which not only carry the packages in the indexv able chambers but which also load the packages into and unload the packages from the chambers.

The invention also resides in the unique and comparatively simple construction of the turret to keep the various chambers in a sealed condition and to avoid the need for using complex valving between the chambers and the vacuum and gas sources.

These and other objects and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a new and improved machine incorporating the unique features of the present invention.

FIG. 2 is a plan view of the machine.

FIG. 3 is a fragmentary cross-section taken substantially along the line 33 of FIG. 2.

FIG. 4 is a perspective view showing a filled and unsealed package of the type which is delivered to and handled by the machine.

FIG. 5 is a perspective view of one of the holders.

FIG. 6 is a plan view of the holder shown in FIG. 5.

FIG. 7 is a fragmentary cross-section taken substantially along the line 7-7 of FIG. 6.

FIGS. 8 and 9 are enlarged fragmentary crosssections taken substantially along the lines 88 and 99, respectively, of FIG. 2 FIG. 10 is a fragmentary cross-section taken substantially along the line 1010 of FIG. 3.

FIG. 11 is a fragmentary cross-section taken substantially along the line l1--1l of FIG. 10.

FIGS. 12 and 13 are enlarged fragmentary crosssections taken substantially along the lines l2l2 and 1313, respectively, of FIG. 2.

package FIG. 14 is a perspective view showing the package after it has been purged and sealed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the invention is embodied in a machine 15 for establishing a controlled and preferably non-oxidizing atmosphere within newly filled packages which herein are shown being comparatively flat pouches 16 (FIG. 4) made of flexible heat sealable material. Thepouches are formed and filled on a Bartelt horizontal intermittent motion packager indicated generally by the reference numeral 17 (FIG. 1), each pouch in this instance being filled with several thin slices of meat such as corned beef or turkey. The flavor and quality of the product may be maintained for a longer period of time if the pouches are purged of oxygen before their upper ends are sealed.

The present invention contemplates a new and improved machine 15 which receives the filled but unsealed pouches 16 from the packager l7 and advances the pouches through several conditioning stations 19 to 24 (FIG. 2) where the pouches are periodically evacuated and filled with a non-oxidizing gas to establish an extremely low oxygen level in the pouches. The machine then seals the upper ends of the pouches in the presence of a non-oxidizing gas and therafter automatically delivers the completed pouches to a remote station for further processing. By purging the pouches of oxygen with a machine 15 which is separate from the main packager 17, a lower oxygen content may be established and particularly when the pouches contain a difficuIt-to-fill product such as sliced meat which com plicates purging by the methods presently available for use on the packager itself.

More specifically, the machine 15 includes a turret 25 (FIGS. 1 and 2) which is located near the discharge end of the packager I7 and which is adapted to be indexed step-by-step about an upright axis in timed relation with the delivery of the newly filled pouches 16 from the packager. The turret is formed with twelve angularly spaced shells 26 (FIG. 3) which define separate upwardly opening chambers 27 each adapted to be loaded with a pouch. Associated with each chamber is a pouch holder 29 (FIGS. 5 to 7) adapted to move between an extended position raised out of the chamber and a retracted position located in the chamber (see the two positions shown in FIG. 3). At a loading station 30 (FIGS. 2 and 3), a pouch from the packager 17 is delivered automatically intoeach holder while the latter is in its extended or raised position and while the turret 25 is dwelling. Thereafter, the turret is indexed one step to a station 31 (FIGS. 3 and 8) and the holder and the pouch are lowered downwardly into the associated chamber 27.

During subsequent indexing of the turret 25, each newly loaded chamber 27 dwells successively at two angularly spaced vacuum stations 19 and 20 (FIG. 2). a gas station 21, two additional vacuum stations 22 and 23 and an additional gas station 24. At each vacuum station, each chamber communicates with a vacuum source 33 which evacuates the air from the chamber to exhaust the oxygen from the pouch 16. At each gas station, each chamber communicates with a source 34 of non-oxidizing gas such as nitrogen which is introduced into the pouch to drive out any trapped oxygen. As a result of the multiple purgings, the. oxygen content of the pouch is reduced to a very low level.

After leaving the gas station 24, each chamber 27 is advanced to a closing or sealing station 35 (FIGS. 2, 12 and 13). As the turret dwells at the sealing station, the holder 29 is raised out of the chamber to place the pouch 16 in an overlying enclosure 36 where the top of the pouch is sealed, the enclosure being filled with nitrogen so as to prevent oxygen from entering the pouch when it is raised from the chamber for sealing. The sealing is effected by a pair of opposed heated seal bars 3611 which are'disposed within the enclosure and which are adapted to be reciprocated by conventional airoperated mechanism indicated generally at 3612. When sealed, the pouch appears generally as indicated in FIG. 14.

After being sealed, the pouch 16 is lowered out of the enclosure 36 and back into the chamber 27 and is indexed two steps to a station 37 (FIG. 2). The holder 29 then is raised out of the chamber once again and finally is indexed one additional step to an unloading station 39 where the pouch is automatically removed from the raised holder. On the next index, the holder is advanced to the loading station to receive another pouch from the packager 17.

The turret 25 is supported rigidly on the upper end ofa vertical shaft 40 (FIGS. 3 and 10) which is adapted to be rotated intermittently by a right angle index drive 41 (FIGS. 1 and 3) mounted on the machine support or frame whose various elements have been indicated collectively by the reference numeral 43. An input shaft 44 (FIG. 1) is connected to the index drive 41 and is rotated continuously by chain drive 45 connected to the power-driven cycle shaft 46 of the packager l7.'

Each of the shells 26 of the'turret 25 is box-like in shape and slidably receives an upright rod 47 (FIG. 3) whose upper end carries the pouch holder 29. When the shell 26 is indexed one step past the loading'station 30 and into the lowering station 31, a pair of flanges 49 (FIG. 8) on the lower end of the rod move into straddling relationship with a lug 50 carried on a vertically movable chain 51. As the'shell dwells, the chain drives the lug 50 downwardly to shift the rod 47 downwardly and thus move the raised holder 29 downwardly into the chamber 27 defined by the shell 26 (see the position shown in phantom in FIG. 8). After the turret 25 indexes, the chain 51 returns the lug 50 to its original position to await the rod 47 of the next shell. A similar chain 53 and lug 54 (FIG. 10) are located at the raising station 37 adjacent the unloading station 39 but are driven in a direction to shift each holder 29 upwardly out of its respective shell 26 when the latter dwells at the raising station. The chains 51 and 53 are connected to a right angle gear box 55 which, in turn, is driven intermittently by a parallel index drive 56 (FIGS. 1 and 2) whose input shaft 57 is connected to the turret input shaft 44 by a chain 59.

Just after each holder 29 moves past the lowering lug 50, the flanges 49 on its rod 47 ride onto a rail 59a (FIGS. 3, 10 and 11) which supports the holders vertically when the latter are in their lowered positions. A vertically spaced rail 5912 supports the holders in their raised positions from the time the holders leave the lifting lug 54 until the time they are picked up by the lowering lug 50.

To first raise and then lower each holder 29 when the latter is in the sealing station 35, a vertically reciprocable'slide 60 FIG'. 11') is suppor'ted beneath the sealing station and carries'a lug '61 w hich 'the' flanges 49 on each rod 47 straddle as the rod moves into the sealing station. When the rod dwells, the slide 60 shifts first upwardly and then "downwardly toraise and lower the holder. The slideis reciprocated by acam 63 which is rotated by the'stub end 64 of the turret input shaft 44 and which is connected to the slide by a follower and lever mechanism indicated generally by the reference numeral'65.

Each pouch holder 29 comprises an oblong body 66 (FIGS. 5 to 7) fabricated from plastic and oriented with its long horizontal axis extending along a radius of the turret 25. A compartment 67 for receiving the pouch 16 is defined within the body and opens both outwardly and upwardly. At the loading station 30, each pouch is delivered edgewise and radially into the compartment with the lower end of the pouchbeing received in and guided by a narrow slot 69 (FIG. 5) formed in the body at the lower end of the compartment. Two wires 70 are located on opposite sides of the compartment adjacent the upper end thereof and gradually taper toward one another as they progress toward the inner end of the compartment. The wires help guide the pouch into a pouch clamp 71 having a fixed jaw 73 and a movable jaw 74, the latter being carried on a torsion rod 75 (FIG. 7) which urges the movable jaw toward the fixed jaw. When the holder first dwells at the loading station 30, an air-actuated cylinder76 (FIG. 2) on the frame 43 moves an L-shaped operating mq ber 77 into engagement with an ear 79 (FIG. 5) on the movable jaw so as to wind up the torsion rod, open the clamp 71 and permit the pouch to move between the jaws. Thereaf- I ter, the cylinder retracts the operating member to cause the jaw 74 to close and grip the pouch within the holder. A similar cylinder 80 and operating member 81 (FIG. 2) are located adjacent the u nloading station 39 and serve to open each clamp dwelling that station so that the pouch may be removed from the holder.

To deliver the pouches 16 into the holders 29 at the loading station 30, an intermittently movable conveyor chain 83 (FIG. 1') is disposed in a vertical plane adjacent the loading station and extends to the downstream end of the packager 17. The conveyor chain carries spaced clamps 84 each adapted to pick' up a pouch coming off of the packager and then to carry the pouch into the holder for gripping by the clamp 71 (see FIG. 3). Suitable means (not shown) are provided for opening the clamps 84, first at the packager 17 to receive the pouches and then at the loading station 30 to release the pouches. A similar conveyor chain 85 (FIG. 1) with clamps 86 extends outwardly from the unloading station 39 and'serves to pick up the pouches from the holders in the unloading station and to carry such pouches outwardly away from the turret 25 for further handling.

One of the important features of the invention is that the chambers 27 are tightly sealed as they advance between the purg'ing stations 19 to 24 and that communication between the chambers and the vacuum and gas sources 33 and 34 is established without the need of complex valving. These ends are achieved through the provision of a stationary member or plate 87 (FIGS. 1 and 3) which is rigidly secured to the frame 43 and which overlies'the top'of the turret 25. The underside of the plate 87 is precisely flat and horizontal and mates intimately with a high density polyethylene seal gasket 89 (FIG. 3) anchored to the upper side of the turret, the gasket being formed with openings which overlie and register with the chambers 27. Thus, the plate and the gasket coact to isolate the chambers from one another and to prevent the outside atmosphere from entering the chambers as the latter advance between the first vacuum station 19 and the sealing station 35. Holes 90 are formed through the plate at the sealing station 35 and between the raising-and lowering stations 37 and 31 in order to enable the holders to move into and out of the chambers 27.

To evacuate the chambers 27, the vacuumsource 33 is connected to several lines 91 (FIGS. 2 and 3) which extend through the plate 87'at the vacuum stations 19,

20, 22 and 23 and communicate with the chambers as the chambers move into those stations. In a similar manner, the gas source 34 is connected to lines 93 (FIG. 2) extending through the plate 87 at the gas stations 21 and 24 and is further connected to an additional line 94 (FIG. 13) leading to the enclosure 36 at the sealing station 35. The vacuum and gas sources are operated continuously and, since the chambers 27 move around to the different stations 19 to 24 and the station 35, there is no need to provide shut-off valves in the individual lines 91, 93 and 94.

To summarize briefly, each pouch 16 discharged by the packager 17 is picked up by the conveyor chain 83 and is placed in the raised holder 29 at the loading station 30 After the turret has been indexed through one step to the station 31, the holder and the gripped pouch are lowered by the chain 51 to retract the holder downwardly into the chamber 27 and beneath the plate 87. The pouch then is indexed through the purging stations 19 to 24 where virtually all of the oxygen in the pouch is removed by virtue of the evacuating and gassing. After reaching the sealing station 35, the holder29 is raised upwardly into the enclosure 36 by the cam 63 so that the pouch may besealed by the bars 36a in the presence of the non-oxidizing gas in the enclosure. The cam then lowers the holder back into the chamber 27 and, after the holder has been indexed two steps to the station 37, the chain 53 shifts the holder to its raised position preparatory to the holder being indexed tothe unloading station 39 for removal of the pouch, by the conveyor chain 85.

I claim as my invention;

1. A machine for establishing a non-oxidizing atmosphere within open-ended packages and for closing the open ends of the packages, said machine comprising a support, an indexable turret rotatable step-by-step about a predetermined axis on said support and having a series of open-ended chambers spaced angularly around said axis, each of said chambers stopping at angularly spaced loading, conditioning and closing stations when said turret dwells between steps, a package holder associated with each chamber and movable between an extended position located out of the chamber and a retracted position disposed in the chamber, each of said holders being in its extended position when the associated chamber is in said loading station whereby a package may be loaded into the holder, means for retracting each loaded holder into its respective chamber prior to advancement of the chamber into the conditioning station, a stationary member located in said conditioning station and sealing off the open end of each chamber in the conditioning station, means communicating with each chamber in the conditioning station for establishing a non-oxidizing atmosphere within the package in such chamber, means for extending each holder from .itsrespective chamber after such chamber advances into said closing station, and means in said closing station for sealing the open end of the package in each extended holder in the closing station thereby to maintain the non-oxidizing atmosphere within the package.

2. A machine for establishing a non-oxidizing atmosphere within open-topped packages and for closing the tops of the packages, said machine comprising a support, an indexable turret' rotatable step-by-step about an upright axis on said support and having a seriesof upwardly opening chambers spaced angularly around said axis, each of said chambers stopping at angularly spaced loading, conditioning and closing sta tions when said turret dwells between steps, a package holder associated with each chamber and movable between a raised position located out of the chamber and a lowered position disposed in the chamber, each of said holders being in its raised positionwhen the associated chamber is in said loading station whereby a package may be loaded into the holder, means for lowering in the conditioning station, means communicating with each chamber in the conditioning station for establis hing a non-oxidizing atmosphere within the package in such chamber, means for raising each holder" from its respective chamber after such chamber advances "into said closing station, and means in said closing station for sealing the top of thepackage in each raised holder' in the closing station thereby to maintain the nonoxidizing atmosphere withinthe package.

3. A machine defined in claim 2 in which there are a plurality of angularly spaced conditioning stations located between said loading station and said closing sta tion, and means communicating with each chamber in' each conditioning station for establishing the ,non-

oxidizing atmosphere within the package such chamber.

4. A machine as defined in claim 3 in which said lastmentioned means include means in at least one condiv tioning station for evacuating the atmosphere from each chamber in such station and further including means in at least one other conditioning station for injecting the non-oxidizing, gas into each chamber in such station.

5. A machine as defined in claim 4 in which said stationary member seals off the upper ends of all of said chambers in said conditioning stations and keeps said chambers sealed off as they advance between said conditioning stations.

6. A machine as defined in claim 5 in which said stationary member comprises a plate overlying said turret, said evacuating means and said injecting means communicating with said chamber through said plate when said chambers dwell in the associated conditioning stations, and means for establishing a substantially gastight seal between the upper side of said turret and the lower side of said plate while permitting said turret to rotate relative to said plate.

7. A machine as defined in claim 2 in which said closing means comprise opposed sealing bars located in said sealing station above said turret, an enclosure surrounding said sealing bars, and means for establishing the non-oxidizing atmosphere within said enclosure.

8. A machine as defined in claim 7 in which said means for raising said holders in said closing station are operable first to raise said holder into said enclosure and then to lower said holder back into the associated chamber after the top of the package has been sealed by said bars and before the chamber is advanced out of said closing station.

9. A machine as defined in claim 2 further including an unloading station located between said closing station and said loading station, and means for raising each holder out of its chamber after the chamber has been advanced out of said closing station whereby the package in said holder may be removed therefrom at said unloading station.

10. A machine defined in claim 2 further including means for automatically loading a package into each raised holder in said loading station and for automatically removing the package from each raised holder in said unloading station.

11. A machine for establishing a non-oxidizing atmosphere in open-topped pouches and for closing the tops of the pouches, said machine comprising a support, an indexable turret rotatable step-by-step about an upright axis on said support and having a series of upwardly opening chambers spaced angularly about said'axis, each of said chambers stopping at angularly spaced loading, first conditioning,'second conditioning, closing and unloading stations when said turret dwells between steps, a pouch holder associated with each chamber and movable between a raised position located out of the chamber and a lowered position disposed in the chamber. each of said holders being in a raised position when the associated chamber is in said loading station, means in said loading station for automatically loading a pouch into each raised holder in the loading station, means for lowering each loaded holder into its respective chamber prior to advancement of the chamber into the first conditioning station, a stationary member overlying said turret and closing off the upper ends of said chambers from the time the chambers are moved to first conditioning station until just prior to the time the chambers reach said sealing station, means in one of said conditioning stations and communicating through said stationary member with each chamber in such station to evacuate the atmosphere from such chamber, means in the other of said conditioning stations and communicating through said stationary member with each chamber in such station to introduce a non-oxidizing gas into such chamber, opposed sealing bars located in said sealing station above said turret, an enclosure surrounding said sealing bars, means for establishing a non-oxidizing atmosphere within said enclosure, means for raising each holder in said sealing station out of its chamber to place the pouch in said holder into said enclosure, said last-mentioned means being operable to lower the raised holder back into the associated chamber after the top of the pouch has been sealed by said bars and before the chamber is advanced out of said sealing station, means for raising each holder out of its chamber after the chamber has been advanced out of said sealing station, and means in said unloading station for automatically removing the pouch from each raised holder in said unloading station. I

12. A machine as defined in claim 11 further including at least two additional conditioning stations located between said first conditioning station and said sealing station, means in one of said additional stations and communicating through said stationary member with each chamber in such station to evacuate the atmosphere from such chamber, and means in the other of said additional stations and communicating through said stationary member with each chamber in such station to introduce a non-oxidizing gas into such chamber.

13. A machine as defined in claim 11 further including at least four additional conditioning stations located between said first conditioning station and said sealing station, means in at least one of said additional stations and communicating through said stationary member with each chamber in such station to introduce a nonoxidizing gas into such chamber, and means in the other additional stations and communicating through said member with the chambers in such stations to evacuate the atmosphere in such chambers.

14. A machine as defined in claim 13 in which said conditioning stations are spaced around said axis such that each chamber advances first into two evacuating stations, then into a gas introducing station, then into two more evacuating stations and then into another gas introducing station.

15. A machine as defined in claim 11 in which said stationary member comprises a plate overlying said turret, and means for establishing a substantially gas-tight seal between the upper side of said turret and the lower side of said plate while permitting said turret to rotate relative to said plate.

Claims

1. A machine for establishing a non-oxidizing atmosphere within open-ended packages and for closing the open ends of the packages, said machine comprising a support, an indexable turret rotatable step-by-step about a predetermined axis on said support and having a series of open-ended chambers spaced angularly around said axis, each of said chambers stopping at angularly spaced loading, conditioning and closing stations when said turret dwells between steps, a package holder associated with each chamber and movable between an extended position located out of the chamber and a retracted position disposed in the chamber, each of said holders being in its extended position when the associated chamber is in said loading station whereby a package may be loaded into the holder, means for retracting each loaded holder into its respective chamber prior to advancement of the chamber into the conditioning station, a stationary member located in said conditioning station and sealing off the open end of each chamber in the conditioning station, means communicating with each chamber in the conditioning station for establishing a non-oxidizing atmosphere within the package in such chamber, means for extending each holder from its respective chamber after such chamber advances into said closing station, and means in said closing station for sealing the open end of the package in each extended holder in the closing station thereby to maintain the non-oxidizing atmosphere within the package.

2. A machine for establishing a non-oxidizing atmosphere within open-topped packages and for closing the tops of the packages, said machine comprising a support, an indexable turret rotatable step-by-step about an upright axis on said support and having a series of upwardly opening chambers spaced angularly around said axis, each of said chambers stopping at angularly spaced loading, conditioning and closing stations when said turret dwells between steps, a package holder associated with each chamber and movable between a raised position located out of the chamber and a lowered position disposed in the chamber, each of said holders being in its raised position when the associated chamber is in said loading station whereby a package may be loaded into the holder, means for lowering each loaded holder into its respective chamber prior to advancement of the chamber into the conditioning station, a stationary member located in said conditioning station and sealing off the upper end of each chamber in the conditioning station, means communicating with each chamber in the conditioning station for establishing a non-oxidizing atmosphere within the package in such chamber, means for raising each holder from its respective chamber after such chamber advances into said closing station, and means in said closing station for sealing the top of the package in each raised holder in the closing station thereby to maintain the non-oxidizing atmosphere within the package.

3. A machine as defined in claim 2 in which there are a plurality of angularly spaced conditioning stations located between said loading station and said closing station, and means communicating with each chamber in each conditioning station for establishing the non-oxidizing atmosphere within the package in such chamber.

4. A machine as defined in claim 3 in which said last-mentioned means include means in at least one conditioning station for evacuating the atmosphere from each chamber in such station and further including means in at least one other conditioning station for injecting the non-oxidizing gas into each chamber in such station.

6. A machine as defined in claim 5 in which said stationary member comprises a plate overlying said turret, said evacuating means and said injecting means communicating with said chamber through said plate when said chambers dwell in the associated conditioning stations, and means for establishing a substantially gas-tight seal between the upper side of said turret and the lower side of said plate while permitting said turret to rotate relative to said plate.

10. A machine as defined in claim 2 further including means for automatically loading a package into each raised holder in said loading station and for automatically removing the package from each raised holder in said unloading station.

11. A machine for establishing a non-oxidizing atmosphere in open-topped pouches and for closing the tops of the pouches, said machine comprising a support, an indexable turret rotatable stepby-step about an upright axis on said support and having a series of upwardly opening chambers spaced angularly about said axis, each of said chambers stopping at angularly spaced loading, first conditioning, second conditioning, closing and unloading stations when said turret dwells between steps, a pouch holder associated with each chamber and movable between a raised position located out of the chamber and a lowered position disposed in the chamber, each of said holders being in a raised position when the associated chamber is in said loading station, means in said loading station for automatically loading a pouch into each raised holder in the loading station, means for lowering each loaded holder into its respective chamber prior to advancement of the chamber into the first conditioning station, a stationary member overlying said turret and closing off the upper ends of said chambers from the time the chambers are moved to first conditioning station until just prior to the time the chambers reach said sealing station, means in one of said conditioning stations and communicating through said stationary member with each chamber in such station to evacuate the atmosphere from such chamber, means in the other of said conditioning stations and communicating through said stationary member with each chamber in such station to introduce a non-oxidizing gas into such chamber, opposed sealing bars located in said sealing station above said turret, an eNclosure surrounding said sealing bars, means for establishing a non-oxidizing atmosphere within said enclosure, means for raising each holder in said sealing station out of its chamber to place the pouch in said holder into said enclosure, said last-mentioned means being operable to lower the raised holder back into the associated chamber after the top of the pouch has been sealed by said bars and before the chamber is advanced out of said sealing station, means for raising each holder out of its chamber after the chamber has been advanced out of said sealing station, and means in said unloading station for automatically removing the pouch from each raised holder in said unloading station.

13. A machine as defined in claim 11 further including at least four additional conditioning stations located between said first conditioning station and said sealing station, means in at least one of said additional stations and communicating through said stationary member with each chamber in such station to introduce a non-oxidizing gas into such chamber, and means in the other additional stations and communicating through said member with the chambers in such stations to evacuate the atmosphere in such chambers.