IE52594B1 - Packaging flowable material in an inert gas atmosphere - Google Patents

Abstract

An apparatus for filling rigid or semi-rigid containers under an inert gas atmosphere is thus provided according to the invention in which an oxygen-sensitive product is subjected to a cleaning and a treatment by an inert gas from a supply station for the product, a filling station being provided at which the product is introduced into a container. In a preferred embodiment according to the invention, a station, at which the lids are put on beforehand, is in flow-connection with the filling station and thus shares the same inert gas environment as the filling station. The apparatus according to the invention makes a continuous filling operation possible and may be both a pretreatment for the placing of a lid and for the subsequent placing of an overlid onto a container to be filled with the product for the purpose of maximum sealing.

Description

This invention relates to packaging flowable material in an inert gas atmosphere, and particularly (but not exclusively) to packaging oxygen-sensitive products such as dried milk ponders.

It is already known to fill metal containers with oxygen-sensitive 5 products by a process in which (a) the containers are filled with a metered amount of the product; (b) metal closures are placed on the rims defining the container mouths and retained loosely in position by clinching under projections around the container rims; (c) the containers are fed in hatches to a gas chamber in which they are evacuated and the partial vacuun then broken to an inert gas such as carbon dioxide or nitrogai; and (d) the closures are seamed on to the containers to close the containers hermetically with the container headspace filled with the inert gas.

Steps (a), (b) and (d) of the above process are carried out co a continuous basis, whereas step (c) is a batch operation. If, for any reason, the containers of a batch anerging iron the gas chanber are subject to any substantial delay before seaming, the possibility of axygaa ingress during the delay may render it necessary to repack the cans or scrap them altogether. A further disadvantage of the batch operation of step (c) is that a very substantial area of floor space is required by the gas chanber and its associated marshalling areas.

An alternative to this batch system is found in U.S. Patent No. 3,135,303, in which powdered product is again fed into containers wbich are then evacuated and gassed. By contrast, British Patent Specification No. 1,153,696 proposes, as an alternative to evacuation and gassing in the container, 525943 a process in which the product pouring down into the container flows in countercurrent to and is 'washed* by an upward stream of purging gas.

U.S. Patent No. 3,942,301 also discloses purging of the product with gas as it is being filled into the container, followed by flushing of the container (a flexible bag) after filling, and then evacuation of the container immediately prior to sealing.

The prior art further discloses evacuation and flushing of containers prior to filling; U.S. Patents Nos. 2066356, 2,761,604, 2023824, 1,679,386, 3,236,023, 2,931,147, 3443352, 2128227 and 2,064,678.

According to the present invention, there is provided a method of -filling a container with a flowable product, which ccnprises the stQ® of: (a) substantially purging the product of atmospheric oxygen by subjecting it to a partial vacuum and thereafter to an inert gas; (b) filling the container with the already purged product by evacuating the container and adnitting into the evacuated container i) the purged product and ii) an inert gas; and (c) hermetically sealing the filled container with a closure, while substantially preventing any displacement of inert gas from within the filled container by atmospheric oxygen before the container has been so sealed.

The invention further provides apparatus for filling containers with a flowable product, comprising: (a) storage means for said flowable product, way (b) . purging means receiving product frets said storage means, said purging means including means to subject product received therein first to a partial vacuus and then to an inert gas, (c) a container filling station receiving purged product from said purging means, said filling station including means to subject each container to a partial vacuum and to admit purged product and inert gas to the evacuated container, (d) means for applying a closure or closure material to each container after filling, (e) a container sealing station receiving filled containers from said filling station and at which the closure or closure material applied to each container is hermetically sealed on to the container, (f) conveyor means to transport said containers through said filling and container sealing stations, (g) and means preventing the inert gas in a filled container from being displaced by atmospheric oxygen prior to the application of said closure or closure material.

Arrangements according to the invention will new be described, by of exanple, with reference to tbe acccnpanying drawings.

In the drawings :figure 1 schematically shows the apparatus in relation to containers passing along a linear conveyor; figure 2 is an exploded view shewing one of the containers and its associated lid and overcap; figure 3 is a schematic diagram of the bulk storage, purging and filling devices generally disclosed in figure 1; figure.4 is a side view, partially broken away, of cue 58 4 embodiment or tne filling device, lidding oevicc and neat sealer disclosed in Fig. 1; Fig. 5 is a top view, partially broken away, of tbe filling device, lidding device and beat sealer ot Fig. 4; Fig. 6 is a front view, partially broken away, of tne filling device, lidding device and heater sealer of Figs. 4 and 5; and Fig. 7 is a schematic diagram of a continuous motion filling device, lidding device and neat sealer alternative to the apparatus of Figs. 4 to 6 but again proposed for use in filling, lidding and sealing of tbe container of Fig. 2 using tne bulk storage, purging and filling devices of Fig 3.

Referring now to Fig.l of the drawings, there is shown an apparatus arranged for gas-packing plastics containers 10 on a continuously-moving linear conveyor 11 with an oxygensensitive product such as dried milk powder. The containers enter the apparatus from the left as shown, pass througn tne apparatus on a generally linear and horizontal path, and leave the apparatus to the right after product-filling, closing and overcapping as will become apparent. The containers are located, by means not shown, at a regular spacing along tne conveyor.

Tne apparatus, whicn is shown only schematically, comprises a bulk storage silo 12 for the product, a filling machine 13 associated with the conveyor 11 and having one or more filling heads 9 arranged for filling tne containers individually with a metered quantity of product, a lidding machine (generally denoted 14) arranged co stamp lieat-uculjbic lias 15 from a reel 16 of plastics coated metal foil,, anu to pass tnem onto a gravity-feed chute 17 for automatic (i.e. passive} placement onto the containers by a lie applicator 18 as the containers emerge from the filling machine 13, a heatsealing macnine 20 arranged to apply heat and pressure to the lids so as to heat-seal tnem to the rims of the containers and thereby hermetically close the containers, and an overcapping machine 21 arranged to fit tnerraoplastic overcaps 22 onto the containers in overlying relation to the lias 15 so as to give protection to the lids during transit and display and to provide reclosures for the containers at the point of use.

Tne operations of the filler 13, the heat-sealing machine 20 and possibly also the overcapping machine 21 are synchronised with one anotner and with the movement of the containers along tne conveyor. The items 13,18,20 and 21 are shown as being arranged in relation to the conveyor so as to operate on the containers as they pass along the conveyor, but it will be appreciated that one or more of tnese devices, particularly the filler 13 and the heat sealing machine 20, may nave their own turntable by which the containers are progressed through tne device, and a star wheel or wheels to remove.· the containers from the conveyor for processing and return tnem to the conveyor after processing.

After overcapping in the overcapping machine 21, the containers, now denoted 10', leave the apparatus by the conveyor to tne right of Fig. 1, for subsequent packing and despatch.

Fig.2 shows one of the containers 10' and its associated lid 15 (before lidding) and overcap 22. The container ll) itself nas a generally cylindrical side wall 25 rising from a base (not visible) and terminating in a rim 26 which defines the container mouth. It may be moulded from any suitable plastics material, laminated or otherwise, which nas a desired low oxygen permeability.

Tne lid 15 has a generally plane and circular closure panel 30, and a peripneral skirt 31 which is primarily provided to enable the lid to be accurately and reliably placed on the container by the applicator 18. The heat-seal between the lid and the container is made largely over a peripheral margin of the closure panel 30, although it may also be made to extend some way down the sxirt 31. The plastics coating of the lia material is chosen m relation to tne plastics material of the container 10 to which it is required to be heat-sealable. It may be such that the heatseal is peelable, so tnat the consumer may tear away the lid tor use, or it may be such that heat-seal is effectively unbreakable, in which case the lid is cut or torn to provide access to tne container; for that purpose the lid may be scored to define a tear-away panel.

The overcap 22 is injection-moulded from a suitable thermoplastics material such as high desnsity polyethylene.

It has a closure panel 40 to overlie the closure panel 30 on tne lid 15, and a peripheral skirt 41 to surround the lid skirt 31. The skirt 41 is formed with a continuous, inwardlyprojecting bead 42 which is arranged to be removably snapengaged in a groove 43 formed around the container below tne rim 26. Preferably, and as shown, the rim is formed on a reduced-diameter neck 44 of the container, the overcap skirt 41 being dimensioned so tbat its exterior surface is flush with that of the container side wall 25 when the overcap is fitted; the groove 43 is then located at the base of the container neck.

Reverting again to Fig. 1, the filler 13, lidding machine 14, beat-sealing machine 20 and overcapping machine 21 are individually conventional.

The filler 13 is arranged to draw a partial vacuum in the containers individually, and to then use the partial vacuum to draw the powder product in metered quantities into the containers. An inert gas (e.g. carbon dioxide, nitrogen or a mixture of these two) is supplied from a source 51 via a control valve 52 to the filling heads 9 and thence into the containers being filled. The partial vacuum itself is generated at a source 53 and communicated through control valve 54. The containers 10 are semi-rigid, and the filling beads 9 of the filler have shrouds 55 which keep each container stably in shape by maintaining the same pressure inside and outside the container throughout the evacuation and filling procedure, as will hereinafter be described. . 10 Tne filler.13 has its own hopper 56 for providing a short-term reservoir of product received from the silo 12. This hopper, which feeds the central filling tubes of the filling heads 9, is topped up on an on demand basis from a purging device 60 which may in turn be fed on an on demand basis from the silo 12. The device 60 is a closed vessel or series of closed vessels which is or are connectable to the inert gas source 51 and the vacuum source 53 by respective control valves 61 and 62. Product which has entered the device 60 from the silo 12 is subjected to a partial vacuum from the source 53 and then returned to a substantially atmospheric pressure environment by inert gas from the source 51. In this way the product is purged of a substantial proportion of its contained oxygen. . Because of this purging operation the oxygen content of the product within each container is reduced to the low level (e.g. 2%) commensurate with a long shelf life for the product in the completed container 10'.

The lidding machine 14 is coupled to the filler 13 so that little or no oxygen can enter the containers before lids 15 are applied. The lids then prevent any substantial oxygen ingress before the containers are hermetically closed by the heat-sealing machine 20. If desired, the lids may be applied when the containers are subject to a small sub-atmospheric or super-atmospneric pressure of inert gas so as during movement of the container to the heat-sealing machine either to effect 52584 a temporary seal between lid and container, or to ensure that gas is vented from the container rather than drawn into it. A hood filled with inert gas may be provided to cover the containers as they pass between the lid applicator 18 and the heat-sealing machine 20; alternatively or additionally a drop of liquid nitrogen may be placed in each container between filling and lidding.

For performing its purging action on the product passing to the filler 13 the purging device 60 may either be arranged to operate on a continuous cycle within the on demand control exercised by the filler; alternatively it may be arranged to process the product in batches within one or more chambers, and to pass the processed batches of product to a reservoir from which the on demand requirement of the filler is met. During purging the product may be mechanically disturbed so that each grain of the powder is properly subjected to the partial vacuum and latterly the inert gas.

In a modification of the described arrangement the .lidding machine 14 and the heat-sealing machine 20 are replaced by a diaphragming machine which presents a heatsealable foil to each container in turn, heat-seals the foil to the container rim as a diaphragm forming an hermetic seal for the container, and then severs the diaphragm from the parent foil around the container rim.

Although particularly described in relation to the gasfilling of semi-rigid plastics containers with dried milk, the invention is not to be considered as limited to such an application. The containers in relation to which the invention may be used may be rigid or non-ngia, ot plastics, glass, metal, board or a combination of these, and closed by any suitable type of closure whetner adhered or mechanically attached m position; in addition, the invention may be used with oxygen-sensitive products other than oried milk powder.

Greater detail of the aforementioned process and apparatus for storing, purging-and product tilling may be seen in Fig. 3 of the drawings. Powdered proauct 10a. is stored in bulk storage silo 12 at atmospheric pressure. It is dispensed by means of gravity feed through a conventional cut off valve 125 and through pipe 126 with sifter 127 to purging devices 6 0a. and 60_b Sifter 127 is of conventional design and arranged to prevent any lumps of product, foreign matter, etc from entering the purging devices 60s. and 60b.

Purging devices 60 a.and 60b. are closed pressure vessels which are connected by means of pipes 70, 71 and 72 to a source 51 of nitrogen under pressure. Purging devices 60a and 60b are also connected by means of pipes 73, 74 and 75 to a vacuum source 53 comprising a vacuum pump 154 and associated driving motor 153. Optionally, storage silo 12 may also be connected to inert gas source 51 by means ot pipe 76 to provide a fluidising layer of nitrogen down the inner face of tne silo cone 120 to assist product discharge. Pump 154 is arranged to vent to atmosphere via a valve 57.

In order to pretreat powdered product 10^. with inert gas, so as to drive off substantially all the oxygen present, powdered product 10a. is flushed with inert gas in purging S2594 devices 60a and 60b. Powdered product 10a is dispensed by means of normally open valve 125 through pipe 126 and sifter 127 into purging devices 60& and 60b which are than closed by means of valves 77 and 78 operating in response to respective high level sensors 97 and 98. Cbce closed a vacuun is drawn on the purging devices by means of vacuun source 53 acting through pipes 73, 74 and 75. Vacuun is controlled by valves 62a and 6¾. The vacuun is broken by the introduction of inert gas from inert gas source 51 through pipes 70, 71 and 72. Plow of inert gas is ecu trolled by valves 61a and 61b.

In a preferred embodiment purging devices 60a and 6Ob each hold roughly 2 to 3 tons (2.03 to 3.05 metric tonnes) of pondered product. 2 Vacuum is applied to roughly 20 inches of mercury (67.7 x 10 N/m ) negative pressure. The preferred inert gas, nitrogen, is introduced until pressure vessels 60a and 60b are pressurized to atmospheric pressure or slightly above it. Advantageously, and as indicated, the nitrogen incoming into the purging devices is arranged to form a fluidising layer in the manner of the supply of nitrogen to the silo 12 through pipe 76. fbllowing the purging by nitrogen gas, powdered product 10a is selectively piped from either purging device 60a and 60b through the pipes 83, 84 and 85 into a reservoir 80 which is a closed vessel having a capacity somewhat greater than that of each purging device 60a and 60b. The reservoir is connected to inert gas source 51 so as at all times to have a nitrogen atmosphere approximately at atmospheric pressure.

A lew level sensor 81 detects when the reservoir 80 is able to receive the capacity of one of the purging devices 60a or 60o. An electrical signal is tnen sent tnrougn circuit 67 to one or tne otner or electrically activates aisc valves 88 ana 89; tne selected valve tnen opens, allowing tne wnole contents ot its associated purging device to discnarge into the reservoir 80. Means are provided to ensure that such discharge cannot take place unless the contents of the purginy device have been suogected to an evacuation and purging cycle as described above. After discnarge the respective valve 88 or 89 is closea, and valve 77 or 78 is opened so as to charge the purging device witn product for tne next evacuating and purging cycle.

In general, tne purging devices 60a_and 60o_ will be controlled to operate in counterphase, so that one device is discnargmg and filling wnile tne other device is perrormmg its evacuating and purging cycle.

Tne outlet of the reservoir 80 is connected by pipe 95 to the product inlet of tne filler nopper 56. A valve 96 is provided in pipe 95 to control product flow in response to low and nigh level sensors 86, 93 associated with tne filler hopper. Hopper 56 is connected to inert gas source 51 by pipe 59 so as to be at atmosphere pressure.

One embodiment of conveyor 11, filling machine 13 with filling head 9, lid applicator 18 and heat sealing macnine 20 may be seen in greater detail in Figs, 4 to 6· As seen m Fig. 4, container 10 is brougnt towards filling Read 9 witnin nood 104 Dy means of continuously moving conveyor 11. Hood 104 is supplied with nitrogen at slightly above atwospneric pressure through pipe 113. Conveyor 11 acvances the containers to intermittently moving gripper oars 100 and 101 (Fig 5), which are laterally disposed on each side of the container path. Gripper bars 100 and 101 move in a generally rectangular motion towards each other so as to grip the containers and advance them along the path. As they separate, the containers are left stationary until the next cycle. Each container 10 in turn is thereby positioned under filling head 9. Filling head 9 has a metal shroud 55 with a circular rubber sealing gasket 102 disposed about its base 103. It also has a central filling tube 105 connected to the outlet of the filler hopper 55 and arranged to discharge product through a central aperture in mesh screen 106. Filling head 9 is lowered to cover each container to bring the shroud 55 in enclosing relation witn the container witn its gasket 102 sealing around the container base; movement of the filling head 9 also enters the filling tube 105 with screen 106 into the container mouth. A vacuum is then drawn within the shroud 55 by actuation of valve 54 (Fig. 3) in pipe 94 by which gas conduit 95 to filling head 9 is connected with the vacuum source 53.

The filler head 9 is connected directly to the hopper 56 for product flow therebetween, so that the reduced pressure created in tne container causes the inert gas in the hopper to drive product into tne container. Container 10 then fills until a predetermined quantity of the product 10a_ has entered, at which time the product reaches the screen 106 which thereby cuts off the flow of product. After filling, the vacuum in the gas conduit 95 and filler head 9 (including the headspace of the container) is broken to nitrogen at atmospheric pressure by operation of valve 52 associated with the line 90. Thereafter, container 10 is lidded and sealed by a conventional lidder 14 and sealing machine 20 such as those manufactured by T.I. Fords, Bedford, England.

In the lidder, lids 15 are stamped from a reel 16 of plastics coated metal foil. The lids are passed onto gravity feed chute 17 and individually hung over the container path so as to be picked off by a container 10 and fall loosely into closure forming position onto the container rim 26. Heat sealer 20 thereafter applies approximately 190of> (88°C) for 1.5 seconds, with sufficient pressure to seal lid 15 to nm 26. Tnis is accomplished by means of a heated sealing head 107 which is forced downward onto rim 26. Following sealing the head 107 is raised, and the container 10 continues along the path through the apparatus to a continuation of the conveyor 11.

A particular and advantageous feature of the apparatus is the provision of a means for pretreating the containers before they are filled with product. As shown, this may take the form of a pipe 108 which is connected to the inert gas source 51 and which is supported from filling head 9 by bracket 109 so that when the filling head is lowered onto a container 10 it enters the open mouth of the succeeding container. The nitrogen thereby caused to enter the succeeding container displaces a substantial proportion of the air from the container so as to precondition the container for the filling operation which follows.

The hood 104 covers the container at all times from its 52584 preconditioning by nitrogen from the pipe 100 to its eventual sealing by the sealing machine 20. The oxygen content of the sealed container 10 is thereby held to a level below 21 on average.

An additional feature of the present system is the reduction in the amount of inert gas (i.e. nitrogen) required to maintain the container 10 at such a low level of oxygen content. In this regard, and as shown in Fig 3 of the drawings, a pipe 110 including a valve 111 leads from the exhaust or outlet of vacuum source 53 to the bulk storage silo 12. When the purging devices 60£ and 60b_are being evacuated as described above, the valve 111 is opened (and the valve 57 closed), so that the nitrogen-rich gas left in the purging devices by their previous purging operation is recycled to the product in the silo 12. In this way a substantial proportion of the o.xygen in tbe product in silo 12 will be displaced.

Further pipes 114, 115 and 116 with valves 117, 118 lead directly from the purging devices 60a., 60 b. to the silo 12 so as to bypass the vacuum source 53. These pipes are therefore operative to recirculate gas from the purging devices to the silo 12 during the time that the pressure in the purging devices is superatmospheric and tbe valves 117, 118 are open.

As best seen in Fig 7 of the drawings, in a preferred embodiment of the invention, filling machine 13, lidding machine 14 and heat sealing machine 20 are combined with a container preconditioning device 140 in a unitary and compact mono-block system 141 for which a hood 104 of simple design and construction can be provided.

The preconditioning device 140, machine 13 and sealing machine 20 are rotary machines each having a turntable with lifting platforms 142 and associated actuators (not shown) arranged around its periphery, and a carousel with heads for co-operation with the containers when lifted by respective ones of the lifting platforms. The turntable and the carousel rotate continuously in synchronism. In Fig 7 the turntables of the devices 140, 13 and 20 are respectively denoted by the reference numerals 166, 168 and 170, and their carousels by the reference numerals 172, 174 and 176.

Starwheels 182, 183, 184 and 185 link the devices 140, 13 and 20 operatively together and with the incoming and outgoing portions of the linear conveyor 11, so that the containers may move continuously through the apparatus at a predetermined spacing, being preconditioned, filled and closed as they pass through the devices 140, 13 and 20 respectively. Container preconditioning device 140 and filling machine 13 each comprise a series of metal shrouds 155, 255 respectively which are substantially identical in construction to the shrouds 55 shown in Figs 4 to 6 but mountea on circular carousels 172 and 174. At the device 140 each container 10 is lifted into a metal shroud 155 so that the shroud forms an enclosure with the lifting platform under the container. A vacuum is drawn in each enclosure in turn so as to evacuate the container therein, after which the vacuum is broken by introduction of nitrogen which fills the container to atmospheric pressure.

In the manner described in relation to the previous embodiment, both the drawing of the vacuum and the introduction of the inert gas are performed througn a single conduit (not shown) connecting each metal shroud to the inert gas source 51 and to the vacuum source 53. As before, evacuation and gassing are both controlled by conventional gas valves and electric switching devices.

Following the preconditioning of a container 10 the associated lifting platform 142 is lowered, and the container passes from the turntable 166 and moves via the starwheel 183 onto the turntable 168 of the filling machine 13. The filling machine is a rotary vacuum filler having shrouds 255 of filling heads 9 into which the containers 10 are lifted as the machine rotates, and a vacuum is drawn in the containers. The filling heads are individually as described in relation to the filling head 9 of Figs. 4 to 6. Accordingly, the shrouds 255 have screens 106 as described in relation to Figs 3 and 4. Thus, when each container is full with product up to the level of its associated screen, product flow is halted whereafter the vacuum in the container headspace is broken by introduction of nitrogen from the inert gas source 51 through the same gas conduit as served for the earlier evacuation of the container.

After lowering on its associated lifting platform 142 by the respective actuator, container 10 then passes from turntable 168 to turntable 170 by means of starwheel 184. As it moves around the starwheel 184, lidding machine 14 loosely applies a lid to the container precisely as described in relation to Figs 4 to 6. The lidded container 10 then passes to heat sealing machine 20. A series of heated sealing heads 107 are positioned around carousel 176 so as each to engage a lidded container lifted against it by the lifting platform on wnich tne container is located. The heat and pressure which are thereby applied to the lid seal it hermetically onto the run 26 of the container as described in relation to Figs 4 to 6. Following sealing the container is lowered and the sealed container 10'is moved by starwheel 185 out of the hood 104 and back onto linear conveyor 11.

Disposed adjacent to conveyor 11 is overcapping macnine 21 which aligns a plurality of overcaps 22 in a circular rotating hopper 129'and passes them individually, after orientation, down a chute 130 having a release mecnanism 131 which holds each overcap in turn so as to overhang the end of the chute. Rim 26 of container 10 thereby catches the downwardly hanging overcap and pulls it through the release mechanism 131. Roller 132 then engages overcap 22 fully on rim 26 so tnat it is fixedly attached thereto. It has also been found that attachment of overcap 22 tends to crimp peripheral skirt 31 of lid 15 about rim 26.

Claims (24)

1. CLAIMS:1. A method of filling & container with a flowable product, which emprises the steps of; (a) substantially purging the product of atmospheric oxygen by 5 subjecting it to a partial vacuum and thereafter to an inert gas; (b) filling the container with the already purged product by evacuating the container and admitting into the evacuated container i) the purged product and ii) an inert gas; and 10 (c) hermetically sealing the filled container with a closure, while substantially preventing any displacement of inert gas frcm within the filled container by atmospheric oxygen before the container has been so sealed.

2. The method as defined in Claim 1, wherein the product is a 15 particulate product that is delivered iron a bulk storage container to purging moanc where the product purging step takes place, the purged product being thereafter delivered to filling means for the container, and the inert gas «knitted to the container during the filling step serving substantially to fill the container headspace and any inter20 stitial spaces of the product in the container.

3. Ibe method as defined in Cl. aim 2, wherein the container is rigid or semi-rigid, the product is delivered from the bulk storage container to the purging means, and there purged, in batches, and the inert gas in the container after filling is at substantially atmospheric pressure. 25

4. The method as defined in Claim 1 or Claim 2 or Claim 3, which includes the further step of preconditioning the container before filling it with product by flushing the container with an inert gas.

5. Ihe method as defined in Claim 1 or Claim 2 or Claim 3, wherein the container is preconditioned by subjecting it firstly to a partial vacuun and thereafter admitting into it an inert gas, before -rming

6. A method as defined in any one the precedl ng cl alma, which includes the further step of applying an overcap to the container in overlying relation to said sealing closure, tbe overcap providing a reclosure for the container in use.

7. Apparatus for filling containers with a flowable product, comprising: (a) storage means for said flowable product, (b) purging means receiving product iron said storage means, said purging means including means to subject product received therein first to a partial vacuum and then to an inert gas, (c) a container filling static» receiving purged product from said purging means, said filling station including means to subject each container to a partial vacuus and to admit purged product and inert gas to the evacuated container, (d) means for applying a closure or closure material to each container after filling, (e) a container sealing station receiving filled containers from said filling station and at which the closure or closure material applied to each container is hermetically sealed cn to the container, (f) conveyor means to transport said containers through said filling and container sealing stations, (g) and means preventing the inert gas in a filled container iron · being displaced by atmospheric oxygen prior to the application of said closure or closure material.

8. The apparatus as defined in Claim 7, wherein the closure is placed on each container at a closure application station situated between said filling and sealing stations, the closure thus placed being heat-sealed to the container at said sealing station.

9. The apparatus as defined in Claim 8, further including an overcapping station positioned downstream of said sealing station and at which an overcap is placed cn the container to cover the heat-sealed closure.

10. The apparatus as defined in Claim 7 or Claim 8 or Claim 9; wherein said storage means includes a storage silo positioned above said filling station.

11. The apparatus as defined in any coe of Claims 7 to 10, wherein said purging means is provided in conduit means whereby the product is delivered from the storage means to the filling station, and sources of vacuun and inert gas are connectable selectively to said purging means.

12. The apparatus as defined in Claim 11, wherein said purging means is arranged to operate batchwise.

13. The apparatus as defined in Claim 11, wherein said purging means is arranged to operate with a continuous flow of product.

14. The apparatus as defined in any one of Claims 7 to 13, wherein said filling station has at least one filling head cocprising a shroud for surrounding a container during filling and filling means within the 52584 shroud to deliver purged product into the container, sources of vacuun and inert gas being connectable selectively to the interior of the shroud.

15. Ihe apparatus as fefined in Claim 8 or Claim 9, or any one of Claims 10 to 14 taken with Claim 8, wherein said closure application 5 static® norprises means to place a metal foil lid, iron a supply of such lids, ca each container as it passes through said station.

16. Ibe apparatus as defined in Claim 15, wherein said closure application station further includes means to successively staap said metal foil lids from a reel of metal foil, and a gravity feed chute for 10 delivering the stamped foil lids frcm said standing means to provide said supply of lids. '

17. Ibe apparatus as defined in any one of Clains 8, 9, 15 and 16, wherein said closure application station and said filling station have a cannon enclosure, within which an inert gas atmosphere is maintained. 15

18. The apparatus as defined in Claim 17, wherein said enclosure extends to enclose also said sealing station.

19. Ibe apparatus as defined in any one of Claims 7 to 18, wherein said storage means is arranged to contain a powdered food product and said conveyor means is arranged to transport containers made of plastics 20. Material.

20. The apparatus as defined in any one of Claims 7 to 19, further including a preconditioning station for preconditioning the containers before they reach the filling station, said preconditioning station including means to introduce inert gas into said containers so as to 25 fill the containers with inert gas.

21. Ibe apparatus as defined in Claim 20, wherein said preconditioning station has a shroud for surrounding each container during preconditioning, sources of vacuun and inert gas being selectively connectable in turn to the interior of said shroud.

22. The apparatus as defined in Claim 20 or Claim 21, wherein said 5 preconditioning and filling stations each comprise a turntable and associated carousel arranged to rotate in synchronism, with means for transferring containers from one turntable to the other, each carousel axnprising respective groups of heads engageable with the containers to effect preconditioning and filling of the containers. 10

23. A method of filling a oontainer with a flowable product, substantially as hereinbefore described with reference to Hg. 1 of the accompanying drawings.

24. Apparatus for filling a oontainer with a flowable product, substantially as hereinbefore described with reference to Figs. 3 to 6, 15 or Figures 3 and 7, of the accompanying drawings.