AU731081B2 - Container pre-gassing method and apparatus - Google Patents

Description

1- P/00/011 Reguhatia 3.2

AUSTRALIA

Patents Act 199 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicants: Actual Inventor: Address for service in Australia: Invention Title: Mervyn William OWSLEY TECHNOLOGY LIMITED and EQUIPMENT a.

Mervyn William OWSLEY CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia CONTAINER PRE-GASSING METHOD AND

APPARATUS

The following statement is a full description of this invention, including the best method of performing it known to us -2- CONTAINER PRE -GASSING METHOD AND APPARATUS This invention relates to a container pre-gassing method and apparatus.

For convenience only the present invention will be described with reference to a container pre-gassing method and apparatus used for pre-gassing containers prior to filling with. a powder of an oxidisable product such as milk powder, coffee powder or the like, for which the invention may be particularly applicable. However it is to be understood that it is not to be limited as such. Moreover because the invention may have other applications it is to be understood that the background art and possible embodiments of the invention as discussed below are given by way of example only.

BACKGROUND ART As. a cont ainier pre-gassing apparatus used for pre-gassing a container before filling with an oidisable product, there is for example a conventional pre-gassing apparatus as shown in FIG. 1, and generally indicated by arrow 1. The conventional pre-gassing apparatus 1 comprises a filling head 2 incorporating a centrally disposed product filling passage 3 with a purge gas inlet 4 and purge gas outlet 5 on opposite sides of the product filling passage 3.

With the pre-gassing apparatus 1, a multi-head rotary filler generally indicated by arrow 9 is used. The multi-bead rotary filler 8 has several inlet chutes 9, provided around a lower periphery of a product hopper 10. These are connected to the filling heads 2. The product hopper 10 is suitably formed so that powder 12 contained therein is guided towards the inlet chutes 9 and thence into the filling beads 2. The product hopper 10 which is rotatable about a central vertical axis together with the filling head 2 assemblies, is filled from an inlet section 14 with pre-gassed powder, which is transferred in an inert gas environment. from a *:-pre-gassing apparatus (not shown in the figures). To allow for rotation of the hopper 10, a :slip seal 16 is provided at the inlet section 14.

Containers 20 to be pre-gassed and filled with pre-gassed powder, are mounted on a turntable 22, with one container 20 beneath each filling head 2. In operation, the turntable 22 rotates EZ2vav.798.doc/35/js -3together with the product hopper 10 and filling head 2 assembly, with the containers 20 being pre-gassed and filled while being rotated, from an entry region indicated by arrow 26 where empty containers 20 are fed onto the turntable 22, to a discharge region indicated by arrow 28, where the pre-gassed and filled containers 20 are removed from the turntable 22 and conveyed to 3 sealing unit or the like (not shown in the figure).

With such a system, once the container 20 has been loaded onto the turntable 22, the filling head 2 is lowered slightly so that a lower rim portion 30. abuts against an upper rim 32 of the container 20. Air in the container 20 is then flushed out by introducing an inert gas such as nitrogen or CO. through the purge gas inlet 4, and removing this gas through the purge gas outlet 5. With this operation, the flushing time and flow rate are set, for example by measuring the oxygen content in the outlet gas, to ensure that all the air in the container 20 is completely flushed out, arnd replaced with the inert gas.

Once all the air has been flushed fromi the container 20, a slight vacuum is applied, for example using the purge gas inlet 4 or the purge gas outlet 5, thus breaking a naturally fonmed powder bridge at the end of the product filling passage 3 and allowing powder to flw into the container The operating speed of the apparatus 1 is adjusted so that the filling of each container 20 is completed by the time the container 20 arrives at the discharge region 28. The container is then transferred under an atmosphere of inert gas, to the sealing unit (not shown) wbere a cap is applied to seal the container With the above system, particularly in the case of deep containers or the like where the air in the container is difficult to flush out, the time taken and amount of inert gas to complete the flushing operation can be considerable, thus adding to operating costs. Moreover, due to the nature of the flushing method for purging the container, it is difficult to ensure that all air is purged from the container.

DISCLOSURE OF THE INVENTION .E232V,%u.198SaucJS4s It is an object of the present invention to provide a container pre-gassing method and apparatus which addresses the above problems with the conventional container pre-gassing method and apparatus, or which at least provides the public with a useful choice.

According to one aspect of the present invention there is provided a container pre-gassing apparatus comprising: a filling head incorporating a product filling passage and a purge gas passage, means for operatively connecting said filling head to a product hopper, and filling head operating means for relatively moving said filling head relative to a container support base between a first position and a second position, the arrangement and construction being such that in said first position a container to be pre-gassed (and filled) can be positioned beneath said filling head on said container support base, and in said second position, said filling head can be positioned inside the container and purge gas introduced to the container through said purge gas passage.

Herein, relatively moving, raising or lowering the filling head means changing a distance 15 between the filling head and the container support base by either moving, raising or lowering the filling head, the container support base, or both the filling head and the container support C. base.

According to another aspect of the present invention there is provided a method of pregassing a container using the above apparatus, said method involving the steps of: positioning a container to be pre-gassed and filled beneath the filling head on the container support base, relatively lowering the filling head relative to the container support base into the container, thereby displacing air the reinside either around a peripheral edge of the filling head or through the purge gas passage, and R232Vau.796Sdoc/JSJs relatively raising the filling bead relative to the container support base while allowing purge gas and/or product to flow into the container to fill the space left by the filling head.

Th~e method may further include a step of filling the purged container by for example applying a vacuum to the container through the purge gas passage, to break a powder bridge formed in the product filling passage and allowing powder to flow into the container through the product filling passage, The product filling operation may of course be started during withdrawal of the filling head.

However with certain products such as coffee and milk powder, it may be preferable to delay the filling until there is a buffer region of inert gas at the bottom of the container.

The purge gas passage may comprise one or more passages passing tbrough the filling head, and may include a space formed between the filling head and an inner wall of the container when the filling head is inserted thereinto.

The means for operatively connecting thie filling head to a product hopper may involve any suitable means, whereby the filling bead may be connected to the product hopper while 15- allowing the product to flow in an environmentally sealed condition from the product hopper to the filling head. In the case where the means for operatively connecting the filling head to the product hopper involves fixed means, then the filling head may be relatively moved relative to the container support base together with the product hopper when relatively moved between the first and second positions.

In the case where the filling head is moved relative to the product hopper during the pregassing and filling operation, the means for operatively connecting the filling head to the product hopper may include means for allowing relative movement between the filling head :5 :and the product hopper while allowing a product to flow in an environmentally sealed condition from the product hopper to the filling head.

Such means may involve for example, a flexible bellows or a sliding seal.

Ef2vau.798.dcflS4s [In the case of a sliding seal the construction may be such that there is provided a hopper guide member for slidingly and sealiogly mounting an inlet portion of the filling head relative to the product hopper.

In this case the inlet portion of the filling head may comprise an e longate walled product funnel in the form of a parallel wall section of for example cylindrical or square cross section, and the product hopper may be formed with an aperture for accommodating the product funnel, the hopper guide member incorporating a seal member for sealing between a rim of the aperture and the wall of the product furinel. With such a construction, the filling head may be moved relative to the product hopper, with the product funnel sliding on the seal member, thus ensuring that product does not escape, and air does not enter. Moreover, the product funnel may be used for controlling the flow of product in the filling operation.

Furthermore, the construction may be such that there is provided a filling head guide member for slidingly and sealingly mounting the filling head relative to a container to be filled.

The filling head guide member may comprise for example an annular member of circular or other appropriate form, for slidingly and sealingly fitting around the filling head, and bias .means for maintaining the annular member in contact with a container being pre-gassed or filled.

With such an arrangement, the container can be sealed from the surroundings during the purging and filling operation, thus minimising loss of purge gas, and ensuring that air does not enter the container.

S Moreover, the end of the purge gas passage of the fillig head may be provided with a gauze filter operation, the filling head may be lowered slightly or the container raised so that a lower rim of the annular member abuts against an upper rim of the container. The filling head may then be lowered into the container, sliding relative to the annular member which seals the top of a gap between the filling head and the, container, and displacing air in the container EZJ2Vau.79§.decfls/js through the purge gas passage. After being fully inserted into the container to displace air therein, the filling head may be removed therefrom, the annular member being held in sealing contact with the top rim of the container by a biasing force of the bias means, and purge gas being introduced to the space in the container left by the filling head, though the purge gas inlet..

The filling head operating means may comprise any suitable means whereby the filling head can be relatively moved between the first and second positions. For example in the case where the filling head is fixedly connected relative to the product hopper, this may involve means for moving the product hopper relative to a container to be pre-gassed and filled.- The relative movement may involve movement of either or bath the product hopper and the container to be pre-gassed and filled.

In the case where the filling head is movable relative to the product hopper, then this may involve means for moving the filling head relative to a container to be pre-gassed and filled and also relative to the product hopper. The relative movement may involve movement of either or both the filling head and the container to be pre-gassed and filled.

In the case where the filling head is movable relative to the product hopper, the filling head operating means may comprise and actuator mounted so as to be operative between the filling head and the hopper. Such, an actuator may for example involve pneumatic operation.

Moreover, a plurality of actuators may be provided as required or desired. In the case of a 20 construction where the filling head moves (for example rotates) together with the containers being pre-gassed and filled, then suitable rotating or sliding couplings may be provided to carry operating power to the actuator.

The method of pre-gassing a container using the above apparatus incorporating the product funnel, may involve for example: lowering the filling head or raising the container so that a lower rim of the annular member abuts against an upper rim of the container, )'W2Vau.798AaJJs -8operating the actuator to lower the filling head into the container, while sliding on the annular member which seals the top of the gap between the filling head and the container, and displa cing air in the container through the purge gas passage, and also lowering the product funnel in the product hopper to a position where product can flow into the product funnel, raising the filling head from the container, the annular member being held in sealing contact with the top rimi of the container by a biasing force of the bias means, and purge gas being introduced to the space in the container left by the filling head, though the purge gas inlet.

The operation may then be completed by breaking a powder bridge at the end portion of the filling passage by applying a vacuum or any other suitable means such as mechanically striking/vibrating the walls, so that powder begins to flow into the container displacing the inert gas, and once the powder level in the container has reached a predetermined level, removing the .:vacujum and allowing powder to bridge the end portion of the filling passage and allowing the container to be released and moved away, with the powder remaining bridged in the end portion of the filling passage.

This invention may also broadly be said to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integer, are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTON OF THE DRAWINGS Further as aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which; E732Vau.798AcWJS~a Fig. I is a schematic cross-sectional view of a conventional container pre-gassing apparatus, used with a multi-head rotary filler, FIG. 2 is a schematic cross-sectional view showing a container being raised towards a filling head (air displacement spacer), with powder bridging in a product filling passage and no vacuum applied; FIG. 3 is a schematic cross-sectional view showing a container in an air displacement position; FIG. 4 is a schematic cross-sectional view sbowing the filling head (air displacement spacer) being lowered into the container, and displaced air being exhausted via purge gas passages; FIG. 5 is a schematic cross-sectional view showing the filling head (air displacemntt spacer) fully lowered into the container, with the displaced air fully exhausted, and a product funnel filled; FIG. 6 is a schematic cross-sectional view showing the filling head (air displacement spacer) :being raised out of the container, with inert gas filling the space left by the filling head (air 15 displacement spacer); :00*.

FIG. 7 is a schematic cross-sectional view showing the container being filled with product, the powder bridge being broken by applying a vacuum so that powder begins to flow into the container, displacing the inert gas; 0 .000 0FIG. 8 is a schematic cross-sectional view showing the powder level in the container reaching gauze filters on the ends of the purge gas passages thus blocking off the vacuum, and allowing powder bridging of the product filling passage; and FIG. 9 is a schematic cross-sectional view showing the condition with the purge gas passages raised to atmospheric pressure thus equalising the pressure and allowing the container to be released and lowered with the powder remaining bridged in the product filling passage.

EM2Vau.7984oc/JSfj% 10 BEST MODE FOR CARRYING OUT THLE INVENTION Figures 2 through 9 illustrate an embodiment of a container pre-gassing method and apparatus according to the present invention.

Components similar to those of the conventional pre-gassing apparatus shown in Figure, 1, are indicated by the same symbols arnd description is hereunder abbreviated or omitted for brevity.

The pre-gassing apparatus according to the present embodiment generally indicate by arrow comprises a filling bead 2 incorporating a product filling passage 3 and purge gas passages 4, 5, as with the conventional apparatus. The filling head 2 is connected to a product hopper 10 by means of an elongate product funnel 52 of cylindrical cross section.

The product hopper 10 is formed with an aperture 54 for accommodating the product funnel 52., and a hopper guide member 56 incorporating a seal member 56' for sealing between3 a rim of the aperture 54 and the wall of the product funnel 52. With such a construction, the filling head 2 may be moved relative to product hopper 10, with the product funnel 52 sliding on the seal member 56', thus ensuring that product contained in the product hopper 10, does :not escape, and air does not enter. Moreover, the product funnel 52 also has the function of .**controlling the flow of product 12 in the filling operation, as described hereunder.

As shown in figures 2 through 9, there is also provided a filling head guide member *generally indicated by arrow 60, in the form of an annular ring member 62, for slidingly and sealing fitted around the filling head 2, and a bias spring 64 (only shown typiclly in figure 2) for maintaining the annular ring member 62 in contact with an upper rim 32 of a container 20 being pre-gassed and filled and mounted on a turntable 22 (container support base). A flexible seal 62' is provided on an inner peripheral rim of the. ring member 62 so that in operation, the container 20 can be sealed from the surroundings during the purging and 25 filling operation, thus minimising loss of purge gas, and ensuring that air does not enter the container.

E232VflU.798.dec/JS6 5 s 11 Moreover, the apparatus 50 is provided with a filling head operating means in the form of a pneumatic actuator 70 fixedly mounted relative to the product hopper 10 so as to be operative between the filling head 2 and the product hopper 10. With (he embodiment shown in the figures, one actuiator 70 is provided for each filling head 2, thus enabling individual operation of the pre-gassing and filling operations. Since with the present embodiment a rotary multi-head rotary filler 8 is used, then a rotating coupling (not shown in the figures) is provided to carry compressed air to the actuators Operation of the pre-gassing apparatus of the abovernentioned embodiment of the present invention will now be described with reference to Figures 2 though 9. The operation of positioning the containers beneath the filling head 2 is the same as for the conventional apparatus described with reference to Figure 1. Hence description of this part of the operation will be omitted.

Once the container 20 has been positioned beneath the filling bead 2 on the turntable 22, then as shown in Figure 2, the container 20 is slightly raised so that the lower rim of the annular 15 ring member 62 abuts against the upper rim 32 of the container 20 as shown in, Figure 3. In ~:this condition powder 12 in the product filling passage 3 is prevented from flowing out due to a powder bridge 80 which forms naturally due to the design of the end of the product filling passage 3.

0. 0* 0 Then as shown in Figure 4, the actuator 70 is operated to lower the filling head 2 into the 20 container 20, while sliding on the annular ring member 62 which seals the top of a ga p between the filling head 2 and the container 20, and displacing air in the container .5SSthrough both purge gas passages 4 and 5. The filling head 2 is lowered to the bottom of the container 20 as shown in figure 5, to fully displace air therein, and so that the product funnel *52 is lowered in the product hopper 10 to a position where product can flow into the product 25 funnel 52.

Then as shown in Figure 6, the filling head 2 is raised from the container 20, with the annular ring member 62 being held in sealing contact with the top rim 32 of the container 20 by the E23ZVau.798.doc/J5/]s 12biasing -force of the bias spring 64. and purge gas being introduced to the space in the container left by the filling head, Ehrough the purge gas passages 4 and 5. With the present embodiment carbon dioxide is used for the purge gas. However, any other suitable gas may be used.

The operation is then completed as shown in Figure 7, by breaking the powder bridge 80 -at the end of the product filing passage 3 by applying a vacuum through either or both purge gas passages 4 and 5, so that powder begins to flow into the container 20 displacing the inert gas.

Then once the powder level in the container 20 has reached a predetermined level as shown in Figure 8, the vacuum is removed to allow the powder to bridge the end portion of the product filling passage 3 and allow the container 20 to be released and moved away, with the powder remaining bridged in the end portion of the product filling passage 3 as shown in Figure 9. With the present embodiment gauze filters are provided on the ends of the purge gas passages 4, and 5, so that when the powder level in the container reaches the gauze filters, the purge gas passages become clogged, thereby blocking off the vacuum.

While the above has been described with the filling head acting as both an air displacement spacer and a filling head. The invention is -not to be limited to this construction, and covers constructions where for example the filling head comprises a displacement spacer for displacing air from a container, connected by sliding or flexible means to a main filling head.

Moreover, the above description has been for the case where the invention is applied to a container pre-gassing operation using a multi-head, rotary flllr. However the invention is also applicable to use with other equipment. For example a single filling head unit or an inline arrangement of filling heads may be suitable in some applications.

Furthermore, with the above embodiment, the filling head has been provided with a seal ring to prevent air from entering the container, and to minimise inert gas usage. However, .E232Vau.79I8aciJSfjx 13 depending on such factors as design, operating speed and tolerances, a seal may not be required.

Moreover, the description has been for an arrangement where the filling head is lowered into the container. However, other arrangements may also be provided as required or desired.

For example the container may be raised relative to the filling head, thus providing a similar effect.

Aspect of the present invention have been described by way of example only and it should be app reciated that modifications and additions may be made thereto without departing from the scope of the invention as defined by the appended claims.

e* I.: 232Vau.79BdcaJS63

Claims (13)

1. A container pre-gassing apparatus comprising: a filling head incorporating a product fil1)ing passage and a purge gas passage, means for operatively connecting said filling head to a product hopper, and filling head operating means for relatively moving said filling head relative to a container support base between a first position and a second position, the arrangement and construction being such that in said first position a container to be pre-gassed can be positioned beneath said filling head on said container support base, and in said second position, said filling head can be positioned inside the container and purge gas introduced to the container thzough said purge gas passage.

2. A container pre-gassing apparatus according to claim 1, wherein said means for *.:operatively connecting said filling head to a product hopper involves fixed means, and said filling head is relatively moved relative to the container support base together with the product hopper when relatively moved between said first and second positions. A container pre-gassing apparatus according to claim 1, wherein said means for operatively connecting said filling head to a product hopper includes means for allowing relative movement between said filling head and the product hopper while allowing a product to flow in an environmentally sealed condition from the product hopper to said filling head.

4. A container pre-gassing apparatus according to claim 3, wherein said means for allowing relative movement involves a sliding seal. A container pre-gassing apparatus according to claim 4, wherein said sliding seal is achieved by providing a hopper guide member for slidingly and sealingly mounting an inlet portion of said filling head relative to the product hopper. P232 Vau .798.doc/15/js

6. A container pie-gassing apparatus according to claim 5, wherein said inlet portion of said filling head comprises an elongate walled product funnel, and the product hopper is formed with an aperture for accommodating said product funnel, the hopper guide member incorporating a seal member for sealing between a rim of the aperture and thle wall of said prod uct funnel.

7. A container pre-gassing apparatus according to claim 6, wherein the arragement of said product funnel enables said product funnel to be used for controlling the flow of product in a filling operation.

8. A container pre-gassing apparatus according to any one of claims 3 through 7, wherein said filling head operating means comprises, means for moving said filling head relative to said container support base and also relative to the product hopper. A container pre-gassing apparatus according to claim 8, wherein said filling head operating means comprises and actuator mounted so as to be operative between said filling head. and the product hopper. A container pre-gassing apparatus according to any one of claims 1 through 9. -herein there is provided a filling head guide member for slidingly and sealingly mounting said filling head relative to a container to be filled.

11. A container pre-gassing apparatus according to claim 10, wherein said filling head guide member comprises an annular member, for slidingly and sealingly fitting around said filling head, and bias means for maintaining said annular member in contact with a container being pre-gassed or filled. :12. A container pre-gassing apparatus according to any one of claims 1 through 11, wherein said purge gas passage of the filling head is provided with a gauze filter.

13. A method of pre-gassing a container using a container pre-gassing apparatus according to any one of claims 1 through 12, said method involving the steps of: E'.32Vau.79B.dac/J5~s 16 positioning a container to be pre-gassed on dhe container support base and beneath the filling head, relatively lowering the filling head relative to the container support base into the container, thereby displacing air thereinside either around a peripheral edge of the filling head or through the purge gas passage, and relatively raising the filling head relative to dhe container support base while allowing purge gas and/or product to flow into the container to fill die space left by the filling head.

14. A method of pre-gassing a container according to claim 13, further including a step of filling the purged container by breaking a powder bridge formed in said product filling passage and allowing powder to flow into the container through the product filling passage. A method of pre-gassing a container using a container pre-gassing apparatus incorporating the product funnel as claimed in claim 7, involving:., positioning a container to be pre-gassed on the container support base and beneath the filling head, lowering the filling head or raising the container so that a lower rim of the annular me Mber abuts against an upper rim of the container, .**operating the actuator to lower the filln head into the container, while sliding on the annular member which seals the top of a gap between the filling head and the container, and displacing air in the container through the purge gas passage, and also lowering the product funnel in the product hopper to a position where product can flow into the product funnel, relatively raising the filling head from the container while introducing purge gas to the space in the container left by the filling head, though the purge gas inlet. .17

16. A method of pre-gassing a container according to claim 15, further including the steps of; filling the purged container by breaking a powder bridge formed in said filling passage and allowing powder to flow into the container through the product filling passage, and once the powder level in the container has reached a predetermined level, allowing powder to bridge the end portion of the filling passage and then moving the container away, with the powder remaining bridged in the end portion of the filling passage.

17. A method of pre-gassing a containir according to claim 16, wherein said step of breaking the powder bridge involves applying a vacuum.

18.. A method of pre-gassing a container according to claim 17, wherein a gauze filter-is provided on the end of said purge gas passage and said vacuum is at least partially shut off once said container is filed by allowing powder to clog said gauze filter.

19. A container pre-gassing apparatus substantially as described herein with reference to ay one oftfigures 2 through 9. A method of pre-gassing a. container substantially as described herein with reference *to any one of figures 2 through 9. DATED THIS 29 DAY OF JULY 1998 CARTER SMITH BEADLE Patent Attorneys for the Applicant: MERVYN WILLIAM OWSLEY AND EQUIPMENT TECHNOLOGY LIMITED E232Vau.798.dactjS4s