WO1996003319A1

WO1996003319A1 - Aseptic bag assembly

Info

Publication number: WO1996003319A1
Application number: PCT/US1995/009333
Authority: WO
Inventors: Stewart Graves
Original assignee: Liqui Box Corp
Current assignee: Liqui Box Corp
Priority date: 1994-07-26
Filing date: 1995-07-26
Publication date: 1996-02-08
Anticipated expiration: 1997-01-26
Also published as: AU3234595A; CA2196176A1

Abstract

A collapsible bag assembly (10) for receiving and containing flowable food products and for use with aseptic filling apparatus (30) is provied. The bag structure (11) is expandable and includes gas impermeable upper (12) and lower (13) walls and a hollow rigid fitment member (20) passing through and secured to the upper wall (12) for sealingly mating with a fill tube mechanism (31) of the filling apparatus (30) for the flow of food products into the bag (11) through an inside passageway (25) of the fitment member (20), which passageway (25) includes guiding rings (33) for guiding the fill tube (31). A plug (27) is movably positioned in the inside passageway (25) at a bottom area for being pushed out of the passageway (25) into the bag (11) by the fill tube mechanism (31). A flange (22) surrounding the fitment (20) may be inclined at an angle (22') for better handling and mating with latch plates, and more secure attachment to the bag (11).

Description

ASEPTIC BAG ASSEMBLY

This application is a continuation-in-part of U.S. Patent Application Serial No. 08/025,849, pending.

Field Of The Invention

This invention relates to a collapsible bag assembly for receiving and containing flowable food products, and for use with aseptic filling apparatus having a fill tube mechanism with a longitudinally movable plunger device.

Backgroun of Th Invention

Collapsible bag assemblies are well known for receiving and containing flowable food products. These collapsible bag assemblies are designed to mate or connect with a fill tube mechanism of an aseptic filling apparatus, which delivers juice, pulp, paste or other food products into the bag. Examples of such collapsible bag assembly and aseptic filling apparatus are disclosed in U.S. Patent 4,445,550 and U.S. Patent No. 4,731,978 to Martensson.

Many aseptically packaged food products are sensitive to the effects of oxygen. These would include light colored fruits such as pineapple, peaches and pears, tropical fruit purees and concentrates such as guava, mango, passion fruit and banana. Other products such as applesauce and many formulated tomato products such as salsa benefit from the lowest level of oxygen contamination. Because -of low production volumes and high values, many of these products are packaged in relatively small bag assemblies.

Significant efforts are made to exclude all oxygen from the products during filling of the bag assembly and to prevent oxygen from reaching the product through the bag assembly.

Oxygen may reach the product in several ways. The oxygen may be entrained in the product and not removed during processing and filling. The oxygen may permeate through the aseptic bag assembly during storage and distribution or the oxygen may be trapped in the bag. Processors of oxygen sensitive products take great care to remove nearly all of the oxygen within the products. This is done by deaeration or by flash cooling. Materials for collapsible bag assemblies used with oxygen sensitive products are carefully selected to provide the best initial oxygen barrier and to maintain that barrier through storage and distribution life of the food product filled bag assembly. Oxygen may be trapped between the material layers when the bag assemblies are made and this oxygen may be removed by various methods.

Another source of oxygen may be trapped oxygen in the fitment or spout used with the bag assembly for filling and dispensing of the flowable food products. As may be seen in the above mentioned U.S. Patent 4,445,550, it is customary to use a frangible membrane across the interior passageway of the hollow fitment to seal the interior of the bag structure from ingress of oxygen and other harmful gases. This membrane is fractured by a longitudinally movable plunger device in the fill tube mechanism of the aseptic filling apparatus after the fill tube has been coupled and sealed with the fitment member so that the flowable food products from the aseptic filling apparatus may flow through the fitment member and into the bag assembly for filling of the bag assembly. An additional difficulty with such a frangible membrane is that the membrane material seldom fractures the same way twice, and often tears into fragments or particles which contaminate the food product flowing into the bag.

Moreover, in a device such as that illustrated in U.S. Patent No. 4,445,550 there is a flange (20) around the spout fitment, to which is attached the bag material itself. However, such a flange is usually made of a plastic material such as high- density polyethylene, which is difficult to process to a substantially flat shape. When the flange is warped, the flexible bag material fixed in annular fashion around the flange tends wrinkle or pinch, which can create holes, larger or smaller. When the fill tube of a device such as that shown in U.S. Patent No. 4,445,550 closes in for filling, latch (55) slide across onto portion (68) , to lock into place for the filling operation, the void in the area of (20, 24) being used up to hold the bag steady. There must consequently be a clear entry for the latch plate to come across and mate cleanly. However, if the flange (20) or other near parts are warped as described, the steel edge of the latch plate can cut a hole in the relatively soft material of the flange.

If a large hole is punched in such a situation, the food product may leak out, and the bag may be lost. If a relatively small hole or a pin hole is created, operators may not notice but bacteria could intrude. Over time, bacteriological reactions can make gas pressure build up in the bag, which can then explode, ruining all of the contents, the bag, and possibly surrounding equipment. To guard against this, operators may have to bend warped flanges out of the way for proper mating, by hand.

Moreover, in a device such as that illustrated in U.S. Patent No. 4,445,550, the fill tube may be intended to form a seal with the spout into which it enters, but making sure that the concentric dimensions appropriately match may be difficult, so that a consistent entry seal may not be guaranteed. Any back pressure in the bag eliminates a true pressure seal, and food product may ooze in uncontrolled fashion, forcing a shutdown of the filling equipment for re-sterilization. Not only that, but if the fill tube enters the spout inclined at an angle in a fitment such as that of U.S. Patent No. 4,445,550 or others, the edge of the fill tube, which may be stainless steel, can shear or gouge the interior surface of the spout, causing peelings or "stringers" which can detach and also contaminate the food product, and lessen the seal. In these and other operations, oxygen is also often trapped in the void space in the internal passageway of the fitment below the frangible membrane.

The importance of any trapped oxygen increases with decreasing bag assembly sizes because of the ratio of oxygen to product volume decreases and there is relatively more oxygen to degrade the product. Regardless of the size of the bag assembly, an unsightly oxidative brown spot can occur on the surface of the oxygen sensitive products due to this trapped oxygen in the fitment member of the bag assembly.

In addition to frangible membrane, flange, handling oxygen and other problems, a device such as that illustrated in U.S. Patent No. 4,445,550 typically represents a receptacle of limited size. For instance, it is known in the art to employ a standard 2" fitment, which receives a fill tube of a certain volume capacity, for instance in fruit product processing. However, a fill tube of too narrow a size may contribute to a back pressure which can cause upstream equipment to break down. There may be a desire to increase the fitment to a larger size, for example 3", to obtain higher volume flow rates and reduce back pressures, but in a membrane-based fitment such as that shown in U.S. Patent No. 4,445,550, this would require strengthening the frangible membrane itself. This is because fitments used in food processing must fulfill hygienic criteria, including to withstand temperature and pressure measures for sterility. For a 2" fitment, this translates to withstanding 40 p.s.i. of steam at 270 degrees for 5 seconds, about 200 pounds of force.

Increasing to a 3" fitment, this translates to withstanding the same 40 p.s.i. of steam at 270 degrees for 5 seconds over an increased surface area, about 350 pounds of force. Strengthening the frangible membrane to withstand these conditions results in a material which may be too tough to pierce to accept the filltube. Increased fitment sizes may therefore be impractical to achieve with a membrane-based design.

In other aseptic bag assemblies such as that illustrated in U.S. Patent No. 4,731,978 to Martensson, the spout is aligned with a mating anterior closing plug (8 et al) , affixed to the back inside wall of the bag. Such a bag receives food product through an inlet member or spout (6 et al) through a fill tube. However, because the closing plug is re-connected after the filling operation so the bag is closed, the closing plug (8) must at all times be carefully connected to and controlled by a rod member (13) , since closing plug (8) must return to engage the spout. This additional structure of course, is more expensive to build and maintain. The rod member (13) is a simple push-pull device, and does not fill food product into the bag.

Also in fitments such as that shown in U.S. Patent No. 4,731,978, the rear wall of the bag is interrupted for attachment of the closing plug, that is, bag membrane (2) is not continuous at the back portion, which can make the bag susceptible to breaks and tears at that juncture. Manufacture of such a back wall structure is practically done by cutting out a disc section, by hand, after the bag is made.

Moreover, in fitments such as that shown U.S. Patent No.

4,731,978 it may be intended for the closing plug (8) to act as a diffuser upon filling. That is, when a fill tube is engaged, product begins to flow and may strike the closing plug, spraying off in different directions for more better distribution. However, if the food product is a viscous material, such as tomato or other paste, some may stick to the closing plug, creating a contaminant coating which upon closing must be sealed through. While as disclosed attempts may be made to remove that type of residue with steam cleaning, it may be difficult to remove the contaminants from all recesses, leaving the possibility is hardened or discolored residue around in the spout/closing plug area. If the food product is a particulate material, product consistency may be affected or the product may be damaged upon striking the plug.

Summary Of The Invention

It is accordingly an object of this invention to overcome the above problems presented by prior aseptic bag assemblies, and to eliminate trapped oxygen and other contaminants in the internal passageway of a fitment member of such bag assembly, or elsewhere.

It is another object of this invention to provide improved sealing between spout and filler tube during the filling process, eliminating backflow and related problems.

It is another object of this invention to eliminate loose particles and other difficulties associated with me brane- based fitments.

It is another object of this invention to eliminate spout stringer and other fill tube engagement difficulties. It is another object of this invention to overcome limited fitment sizes, and achieve scalability to a variety of fitment sizes using the same basic structure.

It is another object of this invention to provide improved mating between spout and filler tube assemblies during the filling process, eliminating inadvertent punctures around the flange, the necessity for manual handling, and other related problems.

It is another object of this invention to provide improved and simplified engagement between spout and filler tube during the filling process, eliminating the need for constantly controlling any closing plug for re-engagement with the spout.

It is another object of this invention to provide an improved rear wall bag structure which is integral and uninterrupted.

It is another object of this invention to eliminate viscous or other residue in the area of the spout.

It is yet another object of this invention to provide an improved and simplified aseptic bag assembly which is simpler, more reliable, and less expensive to manufacture and use.

It has been found by this invention that these and other objects may be accomplished by providing a collapsible bag assembly for receiving and containing flowable food products and for use with aseptic filling apparatus and wherein the bag assembly comprises the following.

An enclosed flexible and expandable bag structure having upper and lower gas impermeable walls. A hollow rigid fitment member passes through and is secured to the upper of the walls of the bag structure and is adapted to mate and seal with the filling tube mechanism of the filling apparatus and defines an inside passageway for the flow of the food products into the bag assembly from the fill tube mechanism. A plug means is movably positioned in the inside passageway of the fitment member at a bottom area for sealing the passageway. The plug means is pushed out of the passageway and into the bag structure by the fill tube mechanism to open the passageway for the flow of food products into the bag structure from the filling apparatus.

Preferably, the plug means further includes means bonding the plug means to an interior surface of the lower wall of the bag structure so that when the plug means is pushed out of the passageway of the fitment member it will be held by the wall of the bag structure out of the path of flow of the food products into the bag structure and will not be released with the food product when dispensed from the bag assembly.

With this construction of a movable plug means located in the bottom area of the interior passageway of the fitment member of the bag assembly, trapped air is eliminated in the lower portion of the internal passageway of the fitment member and is, therefore, not pushed into the bag structure during a filling operation to harm the oxygen sensitive flowable food products. This construction avoids problems encountered with a frangible membrane of the above mentioned U.S. Patent 4,445,550 of plastic particles of the membrane being pushed into the interior of the bag when the membrane is fractured or the fill tube arrives at an angle in the fitment causing "stringers", as well as providing improved fill tube sealing and ready scalability of the fitment to larger sizes.

This construction also eliminates the need for an extra rod member, viscous plug contamination, interrupted back walls and expensive assembly and other problems which may be associated with a bag such as that shown in U.S. Patent No. 4,731,978.

Brief Description Of The Drawings

Some of the objects and advantages of this invention have been stated above, and other objects and advantages will appear from the following more detailed description of the preferred embodiment of this invention, when taken in conjunction with the accompanying drawings in which like portions are designated with like numbers:

Fig. 1 is a perspective view of an aseptic b^σ assembly constructed in accordance with the present invention and snown in collapsed form prior to being filled with flowable food products^■

Fig. 2 is a sectional view of a fit««?nt - sr ic iiag assembly of Figure 1 and taken generally along the -irn 2 of Figure 1;

Fig. 3 is a sectional view, like Figure 2, illustrating a fill tube of an aseptic filling apparatus in mating condition with the fitment member and in process of filling the bag assembly with flowable food products.

Detailed Description Of The Invention

Referring now to the drawings, there is shown in Figure 1 a collapsible bag assembly, generally indicated at 10, constructed in accordance with the present invention for receiving and containing flowable food products and for use with aseptic filling apparatus, generally indicated at 30, having a fill tube mechanism 31 with a longitudinally movable plunger device 32 .

The bag assembly includes an enclosed flexible expandable bag structure 11 having gas impermeable walls 12, 13. These walls 12, 13 may be of any suitable gas impermeable material or multiple layers of material having a barrier layer, etc. The walls 12, 13 may be formed integral or may be secured together around their periphery, as shown in Figure 1, by any suitable means, but as a consequence of the design do not have to be interrupted around the area of the back or lower wall to which is attached plug means 27. Particular types of bag structures and materials are well known to those with ordinary skill in the art, and a detailed explanation of the construction thereof is not necessary for purposes of the present invention.

The bag assembly 10 further includes a hollow rigid fitment member 20 passing through one of the walls 12 of the bag structure 11. The fitment member 20 incites a hollow longitudinally extending tube-like body portion 21 and a bottom transversely extending flange member 22. The flange member 22 extends within the bag structure 11 and on the underside of the upper wall 12 and may be secured to this underside or interior surface of the upper wall 12 by any suitable bonding means 23. The flange member, as illustrated in highlight 22' in Figure 2, may be provided at an inclined angle, preferably about 10 degrees, to enable better guidance for mating with latch plate structures during engagement with fill tube assemblies. This helps to avoid punctures, large or small, from mating assemblies that can lead to oxygen, bacteriological, or other contamination. Moreover, inclined flange portion member 22' causes less stress to the attachment juncture between the bag wall 12 and the flange 22*, reducing the chance of poor sealing.

The fitment member 20 includes a conventional construction for receiving, mating and sealing with the fill tube mechanism 31 of the filling apparatus 30, as shown in part in Figure 3. The fitment member may be constructed of any suitable rigid and gas impermeable material. The fitment member 20 further defines an inside passageway 25 for the flow of food products into the bag structure 11 of the bag assembly 10 from the fill tube mechanism 31 of the filling apparatus 30. The inside passageway may include one or more guiding rings 33, which tend to receive and guide entering fill tube members by contacting their edges, avoiding shearing of the interior surface of the passageway 25 and contaminating "stringers". If further details of mating engagement and of the filling apparatus are desired, reference may be had to the above mentioned U.S. Patent 4,445,550.

The bag assembly 10 further includes a plug means 27 which is movably positioned in the inside passageway 25 of the fitment member 20 at a bottom area thereof for sealing the passageway 25 from ingress and egress of oxygen or other contaminating gases. The plug means 27 may be constructed of any suitable gas impermeable material and has a depth sufficient to eliminate any void space in the bottom of the inside passageway 25 of the fitment member 20. The plug means 27 is pushed out of the passageway 25 and into the bag structure 11 by movement of the plunger device of the fill tube mechanism 31, as shown in Figure 3. Because plug means 27 may be made of injection molded material of cooperating dimensions with passageway 25, and plunger device 32 may be made similarly, relatively close tolerances can be achieved adequate to ensure a consistent seal upon entry of the fill tube mechanism 31, again enhancing protection against oxygen or other contamination. Because the closer tolerances lead to an improved seal, the possibility of product leakage between passageway 25 and fill tube mechanism 31 due to back pressure is reduced. Plunger device 32 of the fill tube mechanism 31 may be a valve which opens the flow of food products material from the filling apparatus 30 through the fill tube mechanism 31 and into the bag assembly 10 through the fitment member 20 and into the bag structure 11. Once plunger device 32 drives the plug means out of passageway 25, there is no need to re-engage plug means with fitment member 20, eliminating the need for maintaining control over plug means 27 throughout the remainder of the filling process and associated equipment for doing so, as for instance required in the assembly shown in U.S. Patent No. 4,731,978. Moreover, since plug means 27 is not re¬ engaged with fitment 20, the possibility of contamination by viscous residue around the plug means in the spout is eliminated.

The plug means 27 is preferably bonded by any suitable means 28 to the interior surface of the lower or bottom wall 13 of the bag structure 11 so that when the plug means 27 is pushed out of the passageway 25 of the fitment member 20 it will be held by the lower wall 13 of the bag structure 11 out of the path of flow of the food products into the bag structure from the filled tube mechanism 31 and out of the bag structure when dispensed. Plug means 27 however does not require that the lower wall 13 of the bag structure 11 be interrupted to be fixed to that wall, eliminating another potential weak spot in the bag structure and enhancing integrity, unlike other systems.

Another significant advantage of the aseptic bag assembly of the invention is that because of the streamlined nature of the interface of the plug means and fitment 20, the diameter of the fitment 20 can be scaled to any desired size without difficulty, unlike membrane-based and other systems, making 3" and lager size fitments a straightforward practical possibility. Moreover, the aseptic bag assembly of this invention is relatively inexpensive to manufacture and maintain, meaning among other things that it can be applied in a cost- effective manner to overall bag assemblies of a variety of sizes, unlike assemblies perhaps such as that of U.S. Patent No. 4,731,978 which may require larger assemblies for economical application. Furthermore, and in keeping with the cost-effective nature of the invention, the aseptic bag assembly of the invention can be used with standard filling tube assemblies, such as those intended for systems like that shown in U.S. Patent No. 4,445,550, with little modification.

Thus, the aseptic bag assembly 10 of this invention has eliminated the problems discussed above with respect to prior bag assembly constructions and, specifically, trapped oxygen in the fitment member of the bag assembly. While this invention has been described above in specific terms, they are used in a descriptive sense only and not for purposes of limitation. The scope of the invention is defined in the following claims.

Claims

WHAT IS CLAIMED IS:

1. A collapsible bag assembly for receiving and containing flowable food products and for use with aseptic 3 filling apparatus having a fill tube mechanism; said bag assembly 4 comprising: an enclosed flexible and expandable bag structure having gas impermeable upper and lower walls; a hollow rigid fitment member passing through and secured to said upper wall of said bag structure with an inclined flange and adapted to mate and seal with the fill tube mechanism of the filling apparatus and defining an inside passageway for the flow of the food products into said bag assembly from the fill tube mechanism; and a plug means movably positioned in said inside passage of sad fitment member at a bottom area thereof for sealing said passage and for being pushed out of said passageway and into said bag structure by the fill tube mechanism to open said passageway for the flow of food products into said bag structure from the filling apparatus.

2. A collapsible bag assembly, as set forth in Claim 1, in which said plug means further includes means bonding said plug means to an interior surface of said lower wall of said bag structure so that when said plug means is pushed out of said passageway of said fitment member it will be held by said lower wall of said bag structure out of the path of flow of the food products into and out of said bag structure.

3. A collapsible bag assembly, as set forth in Claim 1, further comprising guide means secure to said passageway for guiding the fill tube mechanism into said passageway in a substantially straight orientation.

4. A collapsible bag assembly, as set forth in Claim 1, in which said lower wall is uninterrupted.

5. A collapsible bag assembly, as set forth in Claim 1, in which a diameter of said fitment member is scalable to desired dimensions.

1 5

RECTIFIED SHEET (RULE 9D