DK142806B - Method and apparatus for vacuum packaging an object in a bag. - Google Patents

Description

(S

\ Ra ^ (11) PUBLICATION WRITING 142806 DENMARK <61) lnt · Cl · 3 B 65 B 31/02 f (21) Application No. 5592/71 (22) Filed on 5 · noV. 1971 (24) Running leg nOV. 1971 (44) The application presented and ο ί * ν »1 often in the petition published on 2 · χβο. 1 9 ^ 1

DIRECTORATE OF

PATENT AND TRADEMARKET (3 °> Priority gassed from it

Nov 4 1970, 52465/70, GB

(71) W.R. GRACE & CO., 5 Hanover square, New York, N.Y. 10004, US.

(72) Inventor: Giorgio Aldo Maria Giraudi, Via S. Carlo 1510, RH0, Milan, IT: Nino Imperiale, Via S. Carlo, 113 RHO, Milan, IT.

(74) Plenipotentiary in the proceedings:

The engineering firm Budde, Schou & Co._ (54) Method and apparatus for vacuum packaging an object in a bag.

The invention relates to a method of vacuum packaging of at least one article in at least one bag, the method comprising the steps of the preamble of claim 1.

In previous methods of this kind, it has been necessary either to wrinkle the neck of the bag tightly around an evacuation nozzle prior to closing the vacuum chamber, or to substantially collapse the neck of the bag completely into a narrow slot before closing the vacuum chamber.

The process according to the invention is characterized in that it also proceeds as indicated in the characterizing part of claim 1. This provides a considerable simplification, since it is now possible to insert a fully open, filled bag with the bottom in front between the collecting means and into the vacuum chamber, in which a thorough evacuation of the space within the bag is made around the object placed in the bag. such as. a ham. By first enclosing the bag end in an elongated slot and then compressing in the longitudinal direction of the slot to form a tightly knit neck end, it is possible to use simple mechanical means to close the bag neck after the vacuum chamber closure and the evacuation of the vacuum chamber and the bag contained therein.

The method of claim 2 is particularly convenient if the articles to be packaged are hams or have a corresponding shape. Such hams are usually shaped almost like a short cylinder (in the geometrical sense of this word) of oval cross-section. By placing the median plane of the filled bag at the height of the attachment site of the closure clamp, a correct placement of the elongated slot in which the crimped neck is formed by compression is achieved without the need to make separate adjustments to the other mechanical parts. In some cases, the "dead" space inside the bag is also reduced. However, similar advantages can also be obtained with objects having a different shape from the one mentioned.

The invention also relates to an apparatus for carrying out the method according to the invention, and this apparatus is of the kind specified in the preamble of claim 3 and according to the invention is designed as defined in the characterizing part of claim 3.

Claim 4 relates to an embodiment of the apparatus which is particularly convenient and convenient in operation, in that the slot in which the neck of the bag is first assembled lies in the position of use of the apparatus and the collecting members move horizontally along this slot so that the neck of the bag is tightly collapsed. .

The embodiment of claim 5 has the effect that it is possible, by simple means, to sense the movement of the bag into the vacuum chamber and thereby render the bag feeding conveyor inactive, before the filled bag has been moved too far into the chamber, e.g. to a position where it could get in the way of closing the outlet end of the vacuum chamber.

The embodiment of the apparatus according to claim 6 is particularly well suited for carrying out the method according to claim 2.

By means of the embodiment according to claim 7, the apparatus can be easily adapted to objects, e.g. hams, with different heights.

1Λ2306 3

The embodiment of the apparatus as claimed in claim 8 represents a simplification and thus a cheapening of the apparatus, the collecting means being utilized as clamping means. Thus, to the same extent, it is not necessary to have separate clamping means which take up space in the vacuum chamber.

The invention will now be explained in more detail with reference to the drawing, in which: FIG. 1 is a side view of a bag filling station in an automated ham packing apparatus according to the invention.

FIG. 2 shows the embodiment of FIG. 1, seen from above; FIG. 3 is a vacuum chamber used for evacuation and closure of bags filled by means of the bag shown in FIG. 1 and 2, side view, FIG. 4 shows the embodiment of FIG. 3 from above, and FIG. 5 shows an embodiment of a shrinkage unit adapted for use with the one shown in FIG. 1-4, side view.

The FIG. 1 and 2, the bag filling apparatus consists of a conveyor table including a belt conveyor 1 for conveyor receiving ham which has just been removed from the cooking molds and is cleaned, for conveying ham along the table to the right towards a further belt conveyor 2 driven by the same power source. but through appropriate drive so that the linear velocity of the conveyor 2 is twice that of the conveyor 1, thereby ensuring that the distance between two consecutive hams on the conveyor 2 is twice that of the same hams. was located on the conveyor 1. The hams are conveyed along the conveyor 2 to an assembly 3, consisting of a photoelectric source and sensor, at which assembly each ham will interrupt the beam and stop the two conveyors 1 and 2. Thus, a ham will be held stationary during a upper sensing plate 5 and between a pair of side sensing plates 4, all of which are then directed against the ham for contact with the ie the upper side and the side surfaces and for measuring the height and width of the ham. The sensing plates 4 and 5 start from a known reference position and the movement of each plate before it touches the ham is measured and used to derive a signal proportional to the sum of the height and width of the ham. The addition operation is performed using an electric sensing unit in which a downward movement of the top plate 5 and a relative closing movement 4 U2806 of the side plates 4 are added mutually to derive a signal which, when the ham is advanced from the plates 4 and 5, is used to light an appropriate four. selector lamps 6 arranged on a battery tray 7 of support trays adapted to carry different sizes of bags.

Thus, an operator simply needs to select a bag from the tray at the same level as the illuminating lamp 6, and this bag will certainly fit the next ham arriving at the filling station. In practice, the lamp 6 remains lit during the movement of the ham from the sensing station over a battery of rollers 41 and onto a pair of parallel conveyor belts 8 between which a longitudinal slot 8a extends.

The conveyor belts 8 pass the ham past another light source and sensor assembly 9, which generates a beam which is interrupted by the ham and then is re-established when the ham arrives at a position between two side sensing plates 10. The assembly 9 consisting of light source and sensor is thus when the light beam is re-established, the conveyor belts 8 are stopped. The side plates 10 are then driven inwardly to cooperate with the sides of the ham to measure its width, and this width signal is fed to a suitable control arrangement which causes a lateral separating movement of corner plates 11 which forms a filling guide for receiving a bag. . The separation motion is indicated by arrow 13 in FIG. 2. The ham will be advanced from the sensing plates 10 while removing the next succeeding ham from a position between the plates 4 and 5, switching off the lamp 6 before the same or another lamp is switched on as a result of the signal derived by using the sensing plates 4 and 5 to determine the size of the next ham.

When the plates 10 sense the width of a ham being advanced in the bag filling channel delimited by the corner plates 11, the plates 4 and 5 will evidently be simultaneously determining the height and width of the next subsequent ham to effect an ignition of a ham. appropriate bag size selection lamp 6.

Thus, while the corner plates 11 are spread to open a bag for the ham leaving the plates 10, the operator may already be in the process of selecting and opening the bag for the next ham which is just leaving the plates 4 and 5.

The contact plates 11 always start from a position close to each other in which the operator can easily insert the bag over them. Initially, the plates 11 are separated by an adjusting movement outwards in the lateral direction along the arrows 13 so that the width of the filling guide or filling channel is equal to the width of the ham, as this width is sensed by the plates 10. Next, the upper pair of plates 11 which is pivotally mounted is raised. , and is spring loaded, by a movement along the direction of arrow 14 until the bag is tightened to the desired degree, causing a pivot of the spring loaded plates and a conversion of suitable microswitches not shown. The degree of spring tension can, of course, be adjusted for adaptation to the particular bag material used.

This triggering of the limit switches due to the resistance exerted on the upper arms 11 of the bag initiates a feed of the ham from the second sensing position between the plates 10 and into the non-narrowing bag filling channel formed by the guide corner plates 11. This movement of the the ham is carried out by means of a pushing means arranged in the above-mentioned slot 8a. For clarity, the pushing member is not shown in the drawing. It consists of a forward arm which cooperates with the rear portion of the ham and pushes it in, along with and then out of the guide 11, carrying the bag in this movement. The movement of the ham by means of the pushing means continues along the direction of the arrow 15 until the ham reaches the position indicated by dashed lines at 16 on the entrance conveyor 46 of the chamber, on the threshold of the evacuation chamber, cf. FIG. Third

The pushing means is placed under the plane of the various conveyors 1, 2 and 8 as the ham is advanced from the first sensing station or the size sensing station 4, 5 to the second sensing station or the width sensing station 10, and it is then lifted as soon as the ham has been sensed between the side plates 10. The battery of rollers 41 carried by a pair of levers is lifted, thereby allowing the pushing member to move forward and upward along the direction of arrow 15 in FIG. 1 so that it emerges from a location beneath the rollers 41. The feed and return stroke pushing means is shown in FIG. 1 by arrows 15 and 17 respectively.

In order to achieve a time saving for the bag evacuation operation, in the embodiment of FIG. 3 and 4 used a double evacuation chamber which can simultaneously evacuate two bags side by side. In this way, the amount of ham delivered can be increased to a value of the order of 10 ham per per minute, which is the maximum practically applicable throughput rate for the currently used cooking and molding plants.

The filling of the dual chamber is controlled by two parallel arrangements of conveyor rollers 19 and 20 which, when required, can be driven around in such a direction as to feed a ham. Between the individual rollers in the arrangements 19 and 20, side switching rods 18 are arranged which move vertically and horizontally between the arrangements so that hams are alternately transported from the position 16 of the rollers 20 to a parallel position 16a on the other of the rolling arrangements 19. The function of the adjustment bars 18 are adapted to the function of the ham filling guides 11 and the conveyors 8 such that the adjustment guides carry out one cycle in the form of a lateral movement for every two cycles of the filling channel. The adjusting rods 18 are lifted for lifting the ham 16 so as to clear the rollers 20, then they are moved horizontally to a position next to the rollers 19, and finally lowered to place the ham 16 on the rollers 19, after which the rods 18 move. horizontal to a position below the rollers 20.

Once the operation of the machine has progressed to a point corresponding to the arrival of two consecutive hams on the arrangements of rollers 18 and 20 and the side switching bars 18 are retracted to a level below the rolling arrangement 20, the rollers 19 and 20 are driven around to feed two hams. , side by side into the open vacuum chamber. The chamber contains a pair of feed conveyor belts 21 and main conveyor belts 22 arranged to form two parallel ham webs, one along each side of the chamber. The conveyor belts 21 are separated from the belts 22 at a space in which is arranged a vertically movable sensing roller 24. To the left of the sensing roll 24 is a groove extending laterally across the chamber and containing four clamping means. , the operation of which is discussed separately in the following. The conveyors 22 are stopped once the trailing edge of each ham is passed over the sensing roll 24, and has enabled the roll to be lifted to indicate the arrival of two hams at their clamping positions. The conveyor belts 22 are movable in a vertical direction so that they can be lowered a distance corresponding to half the height of an average ham to be baled so that when clamped to the ham, the clamp is substantially at the center plane of the this one, i.e. at the plane midway between the top and bottom of the ham.

After completing the clamping application, the conveyors 22 are lifted again and fed the ham to a dipping shrinkage bath 37, see FIG.

5. The movement of the ham along the conveyors 21 and 22 is, of course, carefully synchronized with the function of the vacuum chamber, so that the cap of the vacuum chamber is lowered only when the ham is completely placed on the conveyor 22. The cap then interacts with the bottom of the chamber in a close manner, after which the air can be evacuated. from the chamber, which now contains two bags side by side, which bag's neck is narrowed as discussed below. Upon obtaining the desired degree of vacuum in the chamber, an air pressure switch is actuated to activate both the final assembly and clamping clamp as well as to activate a cutting operation, in which the excess bag material is largely cut off from the rest of the bag. It is understood that the cut-off operation of free choice may be incomplete so that the excess material remains loosely attached to the other portion of the bag so that the operator can later remove it thereby avoiding the need for separate means for removing the cut end from the bag. chamber as well as avoids the risk of blocking the evacuation lines with the loose, cut bag ends. The subsequent feeding of the vacuum-packed ham to the shrinkage tank is performed automatically once the vacuum chamber cap 26 is lifted.

The dip shrinkage bath shown, seen from the side, in FIG. 5, includes a double-walled tank 37, in the upper part of which is provided a support consisting of a plurality of propelled rollers 38 coupled to a drive shaft by a continuous chain, as in the embodiment shown in FIG. 1 is aligned with a drive shaft and may be coupled thereto by means of a pneumatically operated clock clutch not shown. However, upon arrival of a vacuum-packed ham to the roller arrangement 38, the rotation of the rollers is stopped as the coupling is disengaged and the roller arrangement is lowered into the tank 37.

The tank 37 is also provided with an automatic level sensing and regulating unit to ensure that the level of shrinkage water remains constant. There is also a heating means and a thermostatic control arrangement.

142806 8

In order to avoid loss of steam from the hot water in the shrinkage bath with the consequent need to replace the lost heat and with the disadvantage that the escaping steam absorbed into the ambient atmosphere at the bag filling station can damage any loosely wrapped hams Waiting for the treatment, the support rollers 38 are arranged over a plate 39 which cooperates closely with an inwardly extending flange 39a for the bath. Thus, when the support rollers 38 are in their raised positions, the shrinkage bath is closed. Prior to a downward movement of the rollers 38 for immersing the package, a vaulted cap 40 is lowered to cooperate closely with the top wall of the bath 37. Only when the cap 40 is in its sealing position are the support rollers for immersing the ham in the shrinking medium. which in the present case is made up of hot water.

In order to prevent the ham from floating on top during the immersion operation, the immersion shrinkage tank cap 40 is provided with a perforated basket 45 which, after closing the cap 40, is automatically locked to the support rollers 38 and lowered therewith. In this way, the ham is submerged under the water for the desired period of time to perform the shrinkage. After the shrinking operation is completed, the support rollers 38 are lifted until the plates 39 cooperate with the flange 39a for reclosing the tank.

In this step, the perforated basket 45 is released from the rollers 39 and reattached to the cap 40 which is lifted, carrying the basket.

At this point, the clock clutch is re-engaged and the rollers 38 are propelled to deliver the product to a collection station. It can be seen that curve 45 can be omitted in applications where the gasket is not inclined to float on top of the water but sinks into it due to its own weight.

Any steam that is trapped inside the cap 40 during the immersion operation and which would otherwise tend to disperse after the opening of the dip shrinkage tank will be warmer than the ambient air and will stay inside the cap. Although the steam, while still warm, will normally remain in the downwardly concave cap 40, there is a possibility that the steam will gradually cool and condense and fall into the air below and around the cap as it passes for a short interval in each case. duty cycle is lifted to the one in fig. 9. However, any such possibility can be avoided by incorporating a suitable forced-cooled means, such as a cooling jacket, in the cap 40. In the present case, the forced-cooled member 9 is in the form of water injection means which cool and condense the vapor for a relatively short time interval prior to the opening of the cap. the dipping shrink bath and the condensed vapor drops before the cap 40 opens with the injected water down between the support rollers 38 and mixes with the remainder of the water in the bath 37 during the next dipping cycle. Thus, there is no risk that in the hot air in the area where the cap 40 meets the tank 37, steam will be able to escape when the cap is opened.

It will be seen that the machine shown in the drawing and referred to above constitutes a fully automatic packaging apparatus in which the only necessary manual intervention is the placement of an appropriately sized bag over the corner plates 11 which limit the filling channel. Even the operation of selecting a bag of the correct size is performed mechanically and thus there is virtually no risk of the machine working incorrectly due to operator error.

In the event of an over-sized bag being selected by the operator, the machine will operate perfectly normally and there will be no stopping, although it is possible that the excess bag, even after shrinking, will not fit tightly around the ham. However, if a small bag is selected, the two upper guide plates 11 will detect the tension in the bag prematurely so that their upward movement ceases, and consequently they will block the arrival of the next ham passing into the filling guide. In all cases, the rod 12 extending across the machine at the insertion to the filling guide is lifted together with the upper corner plates or guide members 11, and if the lifting of the rod 12 is stopped before arriving at a position in which it is clear from the top of the the next ham advanced, this next ham will hit a switch plate 12a for stopping the conveyors 8 and the pushing mechanism. The stopping of the conveyors 8 will cause another subsequent ham to interrupt the light beam at the sensing assembly 9 at the input end of the width determination plates 10 and will prevent the beam from being re-established. Conveyors 1 and 2 will thus be stopped and the flow of hams will cease until the operator has been able to remove the incorrectly positioned bag and attach a correct bag to the size of ham which then arrives at the filling station.

10 142806

Although not mentioned above, at the side of the beam 12 facing forward in the feed direction, there is a further switch plate 12b which, during operation of the bag filling unit, must be depressed by the operator to signal that a bag is in place on the guide means 11. The pushing means will not insert the ham into the filling channel until the switch plate 12b is depressed.

The relative movement away from each other and towards each other by the different guide members or corner plates 11 is controlled by a closed hydraulic system acting as a combined brake and locking on the drive mechanism of the corner plates 11. A movement of the members 11 is effected by means of pneumatic jamming forces which at the right time will push their respective piston rods in a direction corresponding to the separation movement of the corner plates 11. Each piston rod carries a secondary piston and extends tightly through a different cylinder within which the secondary piston is sealingly displaceable, the opposing the ends of the secondary cylinder are interconnected by means of a closed hydraulic circuit including a shut-off valve. The size of the horizontal separation movement 13 of the corner plates 11 is controlled in such a way that the hydraulic shut-off valve, when the separation of the corner plates 11 is equal to the width of the ham, the width sensed by the plates 10, is closed and the hydraulic system immediately locks the piston rod. against further movement. In the vertical separation movement in the direction indicated by arrow 14, the vertical movement is also stopped by the associated hydraulic mechanism as the associated limiting switch senses the oscillation of the upper corner plates 11, which is due to the tension in the bag.

The clamping and assembly operation is performed inside the vacuum chamber and is more clearly apparent from the following description of the clamping and assembly means used.

The chamber of FIG. 3 and 4 include a magazine 29 arranged to contain two parallel rows of clamps, each row being associated with the clamping arrangement of one of the two bags within the chamber. The operation of the member is such that the front clamp in each row is moved in the lateral direction as shown by arrow 31 to a position indicated by 36 and in which it aligns with the respective clamp attachment guide 35 carried by the cover 26. In steps, the clamp is ready for application to a bag, and the application simply consists of pushing the clamp upward at the correct time by means of the clamping attachment blade 30 driven by a pneumatic piston and cylinder arrangement. However, the activation of the pneumatic down force 34 can only begin when the neck of the bag is finally assembled. The final assembly is effected by moving the respective pairs of connecting rods 33 laterally across the member toward each other to a position in which they serve as guides for a single U-shaped clamp.

Prior to the final assembly, however, an incipient partial narrowing of the neck of the bag occurs by lowering a transverse bar 32 along with the cover 26 of the chamber to a position in which it is above and at some distance from the sensing roller 24. In this position, the neck of the bag between the sensing roller 24 and the rod 32, but it is capable of accommodating the entire extent of the respective half of the vacuum chamber in the lateral direction.

Thus, the function of closing the chamber causes a partial narrowing of the neck of the bag. The evacuation of the chamber is then effected until the pressure switch indicates that the desired degree of vacuum is achieved, at which time the connecting rods 33 of each pair are moved together to provide the final assembly of the bag neck by bringing the side edges of the constricted bag closer to a position in which it is very close to one another. Once the rods are in this position, it serves as guides for the clamp, as each rod has a slit extending longitudinally along one edge, the struts of each pair being arranged so that their slots face each other. The only thing left then is that the clamping blade is lifted and pushes the clamp 36 up along the guide slots in the cooperating struts 33 so that the free ends of the U-legs cooperate with the clamping matrix 35 and bend to form a tight closure around the neck of the bag.

Once the clamps are securely attached to the neck of the bag, a cutting knife blade 28 is lowered inside the cover 26 of the chamber to provide a partial cut of the excess bag material from the area along the clamp. This causes the cut material to remain inside the chamber and is located by attachment to the bag from which it can later be torn off by an operator, e.g. during the stacking of the packaged hams at the collection station.

The placement of the clamping magazine outside the vacuum chamber of the apparatus shown is considered particularly convenient, the chamber volume to be evacuated only including the vertical passage through which the clamp 36 moves between its "clear position" shown in FIG. . 1 and its "used position" in which it is jammed on the bag. This volume is sealed with respect to the rest of the clamping magazine so that the clamping magazine does not need to be continuously evacuated and re-exposed to atmospheric pressure. This significantly reduces the evacuation volume of the chamber.

Claims (5)

A method of vacuum packing articles in bags having a bag bottom and an open neck end, the method comprising the steps of: a) the article is placed in a bag, b) the bag with the article is inserted into an open vacuum chamber with collecting means arranged for at (c) the vacuum chamber is closed and emptied of air so that both the chamber and the bag not yet provided with a closure clip are emptied of air; and (d) a closure clamp is applied to the neck end of the bag before the vacuum chamber is opened, characterized in e) that the bag, by its introduction into the vacuum chamber, is conveyed in a feeding path between the collecting means, being kept at a sufficient distance therefrom, with the bag bottom at the front and the open neck at the rear, ) the feeding movement of the bag is interrupted while the open neck end of the bag is placed between the collecting means, g) the collecting means being brought together on such that the neck end of the bag is first enclosed in an elongated slit and then compressed along it to form a tightly crimped neck, and h) the closure clamp is applied to the tightly crimped neckline by moving the clamp in a direction perpendicular to the the slit in which the beginning assembly of the neck of the bag took place. Method according to claim 1, characterized in that the movement of the filled bag into the vacuum chamber is interrupted when the bag has passed between the associated set of collecting means and is fully received on a support surface which, when it has fully received the object, is moved vertically downwards through half the height of the filled bag so that the median plane of the filled bag is brought to the level where the closing clip is applied. Apparatus for use in the practice of the method of claim 1 or 2 and of the type comprising a vacuum chamber and a clamping mechanism provided therein for attaching a closure clamp to the neck end of a filled bag inserted into the chamber, characterized by, a) a pair of opposed gap-defining means (24,32) which are parallel to each other and can be moved toward and away from each other to form an elongated slot to partially enclose the neck end of the bag; (b) a pair of collecting means (33) which can be moved towards and away from one another along paths parallel to the slit-delimiting means (24,32), and (c) a conveyor (21,22) forming a bag feeding path passing through through the gap between the gap-defining means (24,32) when they are spaced apart. Apparatus according to claim 3, characterized in that: (a) the slit-deflecting members (24,32) of the apparatus's operating position consist of superposed horizontal bars extending transversely of the pouch feeding path and arranged to move between a open position in which the lower slot-defining means (24) touches the bag feeding path and the upper slot-defining means (32) is so high above the lower that a bag can pass between the lower and upper members, and a slot-defining means a position in which the upper member (32) is lowered close to, but at a small distance above, the lower slit demarcating member (24), and b) the collecting members are constituted by fingers (33) extending vertically and may are moved horizontally towards and away from each other between an open position and a closed position, the distance between them being such that they completely enclose the neck end of a filled bag on the bag feeding conveyor. Apparatus according to claim 4, characterized in that the lower gap-defining means (24) is a horizontal roller arranged for limited transverse movement in the vertical direction and biased or actuated upwards, and which is adapted to control the bag. the operation of the feed conveyor (21, 22) in such a way that it stops when the roller (24) pops up because a bag rolls free of the roller.