WO2010058186A2

WO2010058186A2 - Improvements in or relating to sealing

Info

Publication number: WO2010058186A2
Application number: PCT/GB2009/002736
Authority: WO
Inventors: James A. Kirn; Gert Lourens Jacobus Venter; David J. Drake
Original assignee: Elopak Systems Ag; Burrows, Anthony, Gregory
Priority date: 2008-11-21
Filing date: 2009-11-23
Publication date: 2010-05-27
Also published as: WO2010058186A3

Abstract

A packaging machine has a sterile chamber, a first, lip seal (46) arranged to prevent debris build-up at an access panel (24, 26) used by an operator for accessing the chamber, a second seal (58) arranged to prevent debris build-up between two face-to-face surfaces in the chamber, and a third seal (82) arranged to prevent debris build-up between a shaft and a through hole located inside the chamber.

Description

IMPROVEMENTS IN OR RELATING TO SEALING

The present invention relates to sealing, particularly in relation to a protective chamber of a packaging machine.

In a known type of form-fill-seal packaging machine, used in a dairy or juice plant, fluent material to be packaged is stored in a tank spaced above a conveyor chain. The tank discharges the fluent material, through the use of pumps, into filler nozzles. The conveyor chain carries cartons to be filled to a location underneath the filler nozzles. The containers are indexed under the nozzles, filled, then moved down the line as the conveyor chain advances. In the machine, at least part of the space through which the conveyor advances the containers is maintained "clean" or "sterile" - that is, as a chamber that is either hygienic or aseptic. To this end, the parts of the machine inside this chamber are cleaned periodically by spraying the parts with an internal spray system. The outside of the walls of the chamber are washed periodically to enhance cleanliness.

Another factor in maintaining the cleanliness or sterility of the chamber is air flow. The machine is preferably designed to minimize incursion of outside air into the chamber. To that end, the sterile chamber is typically maintained at a positive pressure, to prevent ambient air from entering and contaminating the chamber. In addition, gaps and openings in the outside envelope of the chamber are sealed.

Because of all of the various mechanical components in the machine, and the high level of cleanliness required in the chamber, many attempts have been made to incorporate the use of various seals in the machine to prevent the buildup of debris and other contaminants in the machine. However, previous attempts incorporating the use of different types of seals have still not provided a satisfactory prevention of contamination in various crevasses among the various parts.

Accordingly, there still exists a need for improved seals and sealing techniques for the prevention of contamination build-up and for the facilitation of cleaning a machine having a protective chamber.

US-A-4,335,075 discloses a sealing arrangement for maintaining sealing between a closed door of a sterilizer and a wall framing an opening into a sterilizer chamber, comprising an endless ring having elastic walls with an internal partition dividing the ring into two independently inflatable, expansible channels. A tube secured to a wall of the ring opens into each of the channels respectively, for independently inflating the channels. Elastic studs with enlarged heads are secured to one side of the ring for detachably engaging in holes in the open wall of the chamber. A pneumatic circuit including a source of compressed air is connected to the two tubes and provided with a two-way valve for inflating either one of the two channels. A pressure responsive switch and solenoid are operatively connected to one of the tubes and valve for closing off the source of compressed air from one channel automatically when pressure falls below a predetermined magnitude, and for supplying compressed air to the other channel to keep the seal between the door and wall of the sterilizer chamber. An alarm such as a lamp may be operatively connected to the pneumatic circuit to indicate automatically that one channel has become deflated and the other channel inflated.

According to a first aspect of the present invention, there is provided an access panel arrangement having a seal for preventing debris from entering a protective chamber, comprising: a frame member; an access panel connected to said frame member such that said panel is movable from a closed position into an open position; and a seal attached to one of said frame member and said access panel for acting when said access panel is in said closed position, wherein said seal will apply sealing pressure to the other of said frame member and said access panel when said chamber is internally pressurized.

According to a second aspect of the present invention, there is provided a method comprising:- providing a protective chamber and an access panel arrangement for preventing debris from entering said chamber, and internally pressurizing said chamber and thereby causing a seal attached to one of a frame member and an access panel of said arrangement to apply sealing pressure to the other of said frame member and said access panel. According to a third aspect of the present invention, there is provided packaging apparatus, comprising a protective chamber having a wall, and a support for a device in said chamber, said support having a surface disposed face-to-face with an inside surface of said wall, and a seal in the form of a ring - A -

substantially co-extensive with an outer peripheral portion of said surface of said support, and disposed sealingly between said surface of said wall and said outer peripheral portion of said surface of said support.

According to a fourth aspect of the present invention, there is provided packaging apparatus comprising a protective chamber, a mounting in said chamber, a hole through said mounting, a shaft extending through said hole, and first and second seals encircling said shaft at respective locations immediately beyond the ends of said hole and bearing sealingly on respective surfaces of said mounting. According to a fifth aspect of the present invention, there is provided packaging apparatus comprising a protective chamber and

(i) an access panel arrangement having a seal for preventing debris from entering said chamber, comprising: a frame member; an access panel connected to said frame member such that said panel is movable from a closed position into an open position; and a seal attached to one of said frame member and said access panel for acting when said access panel is in said closed position, wherein said seal will apply sealing pressure to the other of said frame member and said access panel when said chamber is internally pressurized;

(ii) a support for a device in said chamber, said support having a surface disposed face-to-face with an inside surface of a wall of said chamber, and a seal in the form of a ring substantially co-extensive with an outer peripheral portion of said surface of said support, and disposed sealingly between said surface of said wall and said outer peripheral portion of said surface of said support, and

(iii) a mounting in said chamber, a hole through said mounting, a shaft extending through said hole, and first and second seals encircling said shaft at respective locations immediately beyond the ends of said hole and bearing sealingly on respective surfaces of said mounting.

According to a sixth aspect of the present invention, there is provided packaging apparatus comprising a protective chamber, a first seal arranged to prevent debris build-up at an access panel used for accessing the chamber, a second seal arranged to prevent debris build-up between two face-to-face surfaces in said chamber, and a third seal arranged to prevent debris build-up between a shaft and a through hole located in said chamber.

The various seals of the invention have several beneficial effects. First, they can minimize or eliminate crevices, cracks, etc. where debris, particularly residue, can accumulate. It is in such various spaces that a spray cleaning system can be least effective. As a result, initially the amount of unwanted debris inside a machine can be minimized by the selective design of the areas of the mating parts and of the seals and their placements, and whatever debris is in fact present is more susceptible to removal by the spray system or other cleaning system.

Second, the seals help to minimize any air gaps around attachment points or entry points of pieces to an external wall of the chamber. For example, there are by way of necessity many fasteners or inlets or outlets that extend through the wall. Each such location has the potential to have an air gap. Even if the chamber is positively pressurized in relation to ambient air, the air flowing past such an air gap may create a venturi effect, and draw in outside air.

In order that the invention may be clearly and completely disclosed, reference will now be made, by way of example, to the accompanying drawings, in which:-

Figure 1 is a perspective view from above of a machine having a chamber where seals are used;

Figure 2 is a perspective view from above of part of the machine; Figure 3 is a fragmentary cross-sectional view of a lip seal used according to a first embodiment of the present invention;

Figure 4 is a fragmentary perspective view of the lip seal; Figure 5A is an exploded front perspective view of an access panel arrangement for the chamber and having the lip seal; Figure 5B is the view of Figure 5A, but not exploded;

Figure 6 is a fragmentary, sectional, exploded view of the access panel arrangement;

Figure 7 is an enlarged detail of Figure 6, but not exploded; Figure 8 is the circled portion of Figure 7; Figure 9 is an exploded, fragmentary, perspective view from above of a skin of the chamber and a support in the chamber and having a seal according to a second embodiment of the present invention; Figure 10A is an enlarged, fragmentary, vertical sectional view of a portion of the skin and a portion of the support with the support in an unsecured position;

Figure 10B is a view corresponding to Figure 10A, but with the support in a secured position; Figure 11 is the circled portion of Figure 10A enlarged;

Figure 12 is the circled portion of Figure 10B enlarged;

Figure 13 is a partially exploded, perspective view of a mounting in the form of a base structure, with seals which surround shafts extending through the base structure, according to a third embodiment of the present invention; Figure 14 is a side view of one of the seals used in the third embodiment;

Figure 15 is a fragmentary, vertical sectional view taken along the line and in the direction of the arrows 15-15 of Figure 13;

Figure 16 is a partially exploded, vertical sectional view taken along the line 15-15 of Figure 13; and Figure 17 is the circled portion in Figure 16 enlarged.

A form-fill-seal packaging machine having seals according to the first, second and third embodiments of the present invention is shown in Figure 1 generally at 10. Referring to the Figures generally, the machine has conveyors, generally shown at 12, two types of distributing devices, generally shown at 14 and 15, and a protective chamber 16. The first type of distributing devices 14 in this embodiment is feeders which are used for dispensing pour spout fitments (not shown), otherwise known as "caps", inside the chamber 16 such that the caps may be applied to various cartons 18. The second type of distributing devices 15 in this embodiment is product distribution devices which are used for dispensing fluent material inside the chamber 16 into various cartons 18 prior to the caps being assembled to the cartons 18. The chamber 16 is a sterile environment which is typical of various industries where products used for consumption are packaged.

Access to the chamber 16 by an operator is provided through the use of a series of access panel arrangements 20. As best seen in Figures 3 to 8, the access panel arrangements 20 include a first frame member 22 and a second frame member 24. The second frame member 24 has a transparent sheet 26, which is made of polycarbonate (but may be made of other suitable material) and allows the operator of the machine 10 to view the various processes occurring in the chamber 16. The second frame member 24 also includes a latching handle

28 and a set of hinges 30, so that the panel 24,26 can be swung open to provide access to the chamber 16. The first frame member 22 is mounted and secured to a frame of the machine 10.

The transparent sheet 26 includes a series of apertures 32 which each receive a shoulder insert 34 and a fastener 36. The fastener 36 in this embodiment is a screw. Also included for each fastener 36 is a spacer 38 which is between the second frame member 24 and the transparent sheet 26. The spacer 38 is made of nylon, or other suitable material. The spacer 38 provides a buffer between the second frame member 24 and the transparent sheet 26, and is held in place because the screw 36 extends through the spacer 38. The second frame member 24 includes a set of threaded apertures 40, two of which are shown in Figure 6, which receive the respective fasteners 36 and secure the transparent sheet 26 to the second frame member 24.

The first frame member 22 includes a flange portion 42. Embracing the flange portion 42 is a first seal in the form of a lip seal 46. The lip seal 46 has a

U-shaped body portion 48 and a lip portion 50. During assembly, the U-shaped body portion 48 of the lip seal 46 is pressed toward the first frame member 22 such that the U-shaped body portion 48 covers the flange portion 42, as shown in

Figures 7 and 8. As the lip seal 46 is pressed over the flange portion 42, an adhesive (not shown) is used to secure the lip seal 46 to the flange portion 42.

The adhesive is used to prevent the removal of the lip seal 46 from the flange portion 42.

The lip portion 50 of the lip seal 46 projects outward toward the transparent sheet 26, and is substantially rectangular in shape to form a rectangular, lip sealing area 56 located inwards from the apertures 32 relative to the middle of the sheet 26, so that the lip portion 50 presses against the smooth inside surface of the sheet 26 throughout its periphery. When the access panel

24,26 is closed, as shown in Figures 5, 7, and 8, the lip portion 50 is displaced slightly to the right when looking at Figures 7 and 8 such that the lip portion 50 is in contact with the transparent sheet 26.

When the exterior of the machine 10 is washed, water contacts the first frame member 22, the second frame member 24, and the transparent sheet 26. As the water flows down the access panel 24,26, the construction of the access panel is such that the water will flow down the outside of the access panel 24,26, and the water will not be obstructed by a lip or any other type of significant obstruction. The water will flow around the spacers 38, which are round in shape, and run off the access panel 24,26. Because the water and debris do not collect significantly anywhere, this allows the portion of the access panel 24,26 on the outside of the machine 10 to remain cleaner. The transparent sheet 26 is also located so that only the transparent sheet 26 contacts the lip seal 46; the handle 28 and hinges 30 are on the outside of the second frame member 24, which keeps them outside the lip sealing area 56. Another benefit of the lip seal 46 is seen when the chamber 16 is in use and when the inside of the chamber 16 is cleaned in place. Because the lip portion 50 is pressed against the transparent sheet 26, air forced into the chamber 16 to maintain a positive pressure therein will simply cause the lip portion 50 to become further pressed against the transparent sheet 26, and not allow air to flow past the lip seal 46. Moreover, cleaning fluid forced into the chamber similarly further presses the lip portion 50 against the sheet 26 and so prevents leakage of cleaning fluid past the seal 46. Furthermore, the lip seal 46 and the sheet 26 present a relatively smooth surface to the interior of the chamber, so that debris tends not to accumulate there and, even if it does, the cleaning fluid easily dislodges it.

In the embodiment shown in Figures 9 to12, a plurality of O-ring seals are used for preventing debris from building up at interfaces inside the chamber 16. By way of example, one of the O-ring seals, 58, is used for preventing debris build-up between a support, generally shown at 60, and a wall in the form of a base or a skin 62 upon which the support 60 is located. The support 60 shown is used for supporting a filler nozzle housing (not shown) inside the chamber 16 of the machine 10. The support 60 in this embodiment includes a column 64, two support gussets 66, and a plate-form bottom portion 68. The bottom portion 68 has a ring-form groove 70 receiving the seal 58 and also has, outwardly of the seal 58, a lip 72 so as, with the skin 62, substantially to surround the O-ring seal 58. The support 60 may also include other components which facilitate the use of the O- ring seal 58. However, the O-ring seals may also be used for other supports having other applications where a sealing function is necessary.

Also included are a set of fasteners 74 which extend through apertures 76 in the bottom portion 68 into the skin 62. The support 60 will transition from an unfastened position, shown in Figures 10A and 11, to a fastened position, shown in Figures 10B and 12, as the fasteners 74 are inserted into the skin 62. When the support 60 is in the unfastened position, the diameter of the O-ring seal 58 is large enough that the bottom portion 68 does not contact the skin 62 (as best seen in Figure 11). As the fasteners 74 are used to secure the bottom portion 68 to the skin 62, the O-ring seal 58 is compressed, and so deforms to the cross- section shown in Figure 12. When the bottom portion 68 is secured to the skin 62, the distance between the top of the groove 70 and the skin 62 is smaller than the diameter of the O-ring seal 58. Once the O-ring seal 58 has been compressed, a portion thereof will remain in the groove 70, as shown at 78, and another portion of the O-ring seal 58 will extend out of the groove 70 to underneath the lip 72, as shown at 80.

The O-ring seal 58 in the compressed configuration as shown in Figure 12 serves the purpose of preventing the accumulation of debris between the bottom portion 68 and the skin 62, particularly preventing debris from accumulating in the groove 70. This advantage is provided by the portion 80 extending out of and away from the groove 70. The O-ring seals can be used for a horizontal connection, as shown in Figures 9 to12, a vertical connection, or any variation therebetween. The O-ring seals can also be used anywhere that two mating surfaces come together, where one of the mating surfaces includes a groove, similar to the groove 70, which is suitable for receiving the O-ring seal. Also, the closing of the gap between the bottom portion 68 and the skin 62 (or any other two mating surfaces) prevents a venturi effect from occurring when air is forced into the chamber 16. In the embodiment of Figures 13 to17, a resilient V-seal 82 is used to prevent debris from accumulating between a fixed shaft and other components. This embodiment includes a mounting in the form of a base structure 84 which has a set of through holes 86. Extending through the holes 86 are a set of corresponding shafts 88. Each shaft 88 includes a bore 90 which receives a fastener 92 which secures the shaft 88 to the base structure 84. Each shaft 88 includes a set of threaded apertures 94 which receive a set of corresponding fasteners 96. The fasteners 96 are used for securing a set of guides 98 to the shafts 88. The guides 98 also have a set of apertures 100 through which the fasteners 96 extend. The guides 98 are used for guiding a chain of one of the conveyors 12. The conveyor chain moves along the guides 98 to advance the cartons 18 mentioned above.

To prevent debris from become lodged between the shafts 88 and the base structure 84, the V-seals 82 circumscribe the shafts 88 at locations near the base structure 84. The V-seals 82 each include a lip portion 102 and a base portion 104, which is of a greater thickness than the lip portion 102. During assembly, the V-seals 82 are slid onto the shafts 88 such that their lip portions

102 contact the base structure 84, preventing debris from entering the holes 86 surrounding the shafts 88. The V-seals 82 grip the shafts under their own resiliency, so that adhesive is not required to retain them in position. The V-seals

82 may be used anywhere that a sealing function is necessary between a shaft and another component.

Claims

1. An access panel arrangement having a seal for preventing debris from entering a protective chamber, comprising:

a frame member;

an access panel connected to said frame member such that said panel is movable from a closed position into an open position; and

a seal attached to one of said frame member and said access panel for acting when said access panel is in said closed position, wherein said seal will apply sealing pressure to the other of said frame member and said access panel when said chamber is internally pressurized.

2. An arrangement according to claim 1, wherein said seal is attached to said frame member and will apply sealing pressure to said panel.

3. An arrangement according to claim 2, wherein said access panel comprises a second frame member and a sheet connected to said second frame member, and wherein said seal will apply sealing pressure to said sheet when said sterile chamber is internally pressurised.

4. An arrangement according to any preceding claim, wherein said panel is pivotally connected to the first-mentioned frame member.

5. An arrangement according to any preceding claim, wherein said seal comprises: a U-shaped body portion; and a sealing lip portion connected to said U-shaped body portion.

6. An arrangement according to claim 5 as appended to claim 2, wherein the first-mentioned frame member includes a flange portion disposed in said U-shaped body portion.

7. An arrangement according to claim 3, or any one of claims 4 to 6 as appended to claim 3, and further comprising at least one spacer disposed between said sheet and said second frame member.

8. An arrangement according to claim 3 or 7, or any one of claims 4 to 6 as appended to claim 3, and further comprising:

at least one hole formed in said second frame member;

at least one aperture formed in said sheet; and

at least one fastener extending through said at least aperture into said at least one hole and securing said sheet to said second frame member, the arrangement being such that said seal will apply said sealing pressure to said sheet inwardly of said at least one aperture with respect of the middle of said sheet.

9. An arrangement according to claim 8 and further comprising at least one shoulder insert fitted into said at least one aperture.

10. An arrangement according to claim 8 or 9 as appended to claim 7, wherein said at least one fastener extends through said at least one spacer.

11. Packaging apparatus comprising a protective chamber and an access panel arrangement according to any one of claims 1 to 10.

12. A method comprising:-

providing a protective chamber and an access panel arrangement for preventing debris from entering said chamber, and

internally pressurizing said chamber and thereby causing a seal attached to one of a frame member and an access panel of said arrangement to apply sealing pressure to the other of said frame member and said access panel.

13. Packaging apparatus, comprising a protective chamber having a wall, and a support for a device in said chamber, said support having a surface disposed face-to-face with an inside surface of said wall, and a seal in the form of a ring substantially co-extensive with an outer peripheral portion of said surface of said support, and disposed sealingly between said surface of said wall and said outer peripheral portion of said surface of said support.

14. Apparatus according to claim 13, and further comprising a groove in said support and in the form of a ring and receiving said seal, said seal being oversize for said groove, said support including a lip in the form of a ring and bounding said groove and extending to beyond said seal, which is in a compressed condition and extends into a gap between said wall and the rim of said lip.

15. Packaging apparatus comprising a protective chamber, a mounting in said chamber, a hole through said mounting, a shaft extending through said hole, and first and second seals encircling said shaft at respective locations immediately beyond the ends of said hole and bearing sealingly on respective surfaces of said mounting.

16. Apparatus according to claim 15, wherein said seals include respective annular lips whereby said seals bear sealingly upon said respective surfaces.

17. Apparatus according to claim 16, wherein said seals are each of roughly V-shaped cross-section, said lips consisting respective limbs of the Vs.

18. Packaging apparatus comprising a protective chamber and

(i) an access panel arrangement having a seal for preventing debris from entering said chamber, comprising:

a frame member;

a seal attached to one of said frame member and said access panel for acting when said access panel is in said closed position, wherein said seal will apply sealing pressure to the other of said frame member and said access panel when said chamber is internally pressurized;

19. Packaging apparatus comprising a protective chamber, a first seal arranged to prevent debris build-up at an access panel used for accessing the chamber, a second seal arranged to prevent debris build-up between two face-to-face surfaces in said chamber, and a third seal arranged to prevent debris build-up between a shaft and a through hole located in said chamber.