EP1391399A2

EP1391399A2 - Deformable containment bag for transporting powder

Info

Publication number: EP1391399A2
Application number: EP03255158A
Authority: EP
Inventors: David Bilton
Original assignee: Ice Packaging Ltd
Current assignee: Ice Packaging Ltd
Priority date: 2002-08-21
Filing date: 2003-08-20
Publication date: 2004-02-25
Anticipated expiration: 2023-08-20
Also published as: DE60311926D1; GB0219394D0; GB2392148B; ATE354528T1; EP1391399B1; GB2392148A; DE60311926T2; EP1391399A3

Abstract

There is provided a powder container for storing or transporting powder, the container comprising an elongate deformable plastic bag (40) having an aperture defined at one end being less than half the maximum width of the bag, wherein the walls of the bag taper inwardly between the maximum width to the aperture, which aperture is supported by and defined by an elongate collar (42) connected to the bag.

There is also provided a method of manufacturing such a powder container comprising a deformable bag having an elongate collar.

Description

The present invention relates to containers for transporting powder and, more particularly, to deformable containment bags used as such containers.
A wide variety of industries utilise dry powder in normal manufacturing processes necessitating both the storage and transportation of such powders within the manufacturing environment on a large scale. Examples of such industries include the pharmaceutical industry for the transport of powdered pharmaceutical products, but powder use is equally applicable in other fields such as the food industry, be it the transfer of sugar, flour or any other powdered material, through to the chemical industry for the transfer of paint pigment and other raw materials in a powdered form, necessitating the design of specific containers allowing for safe and secure storage and transport of this powdered material.
Furthermore, many of the powders used in certain industries, and specifically the pharmaceutical industry, are extremely expensive and care needs to be taken to reduce wastage and loss during the transportation and storage of such powders. There is also the need to avoid spillage of such powdered material from a safety point of view since powder of all descriptions, whether they are pharmaceutical or chemical, once airborne pose a potential health risk.
Historically, the bulk transportation of such powdered materials within a manufacturing environment has involved the use of plastic sacks, the drawback of such sacks is that they are limited in their application due to the difficulty in sealing the material within such sacks and the subsequent loss of material when such sacks are opened having usually been sealed by the formation of an irreversible welded seal.
Alternative solutions have therefore involved the use of rigid plastic drums moulded so as to comprise a tapered neck terminating in an opening with an appropriate flange for connection to an appropriate cap or other sealing means. However, the drawback of existing container designs of this type, apart from the high cost of raw materials and manufacture, is that firstly due to their rigid nature such containers necessitate high volume of storage when not in use and, due to their inherent weight, can add considerably to the mass being transported when such containers are fully loaded. Such rigidity further prevents manipulation of the drum and, hence, its contents to aid product flow. A further drawback of the existing container drums of this type is the formation of shoulders or flanges within the container which serve to trap the powder therewithin during the emptying process resulting in a significant amount of wastage during powder transfer.
As such, it is now an object of the present invention to provide an appropriate container for powder transportation and storage which alleviates the aforementioned problems in a simple and cost effective manner.
According to the present invention there is now provided a container for storing or transporting powder, said container comprising an elongate deformable bag having a closed end and a longitudinally opposed open end, which open end defining an aperture therethrough that is less than half the maximum width of said bag, said side walls of the bag tapering inwardly between said maximum width to said aperture, characterised in that the aperture is supported and defined by an elongate sealable collar connected to the bag , the collar having a flange on a free end thereof remote from the bag that is shaped to receive a complimentary shaped coupling flange, of a device to be connected to the bag, a sealing gasket for effecting for a seal between the flange of the collar and the flange of the device, and clamping means for clamping the flanges and the together to form an airtight connection between the device and the bag .
Preferably the flanges of the collar and the device have confronting planar surfaces and confronting grooves, and the sealing gasket comprises an annular member having a planar portion that contacts the planar faces of the flanges and a raised portion.
Furthermore, since the bag is deformable, this also allows ease of manipulation of any powder contained in the bag to aid the flow of such powder.
Usually, the tapered sidewalls of the bag will be inclined relative to a longitudinally extending axis of the bag at an angle of between 20° and 70°. Most preferably this angle of taper will be 30° so as to provide optimum flow of powder along the inclined inner surface when the bag is inverted.
Preferably, the collar itself will be substantially cylindrical and will comprise a flange member along a free end thereof remote from the bag itself. The flange member provides an appropriate means for connecting the bag to a device such as either a sealing cap or an appropriate valve mechanism to allow product transfer, whereby again the collar is substantially rigid to support the bag when connected to a piece of apparatus during transfer of the material to or from such bag.
In addition, it is preferable that the collar will also comprise a conical lead-in face for complimentary engagement with the tapered sides of the bag in the region of the aperture. Whilst it is preferable that the plastic bag may be welded to the exterior surface of the conical lead-in face, it is equally possible that such bag could be welded to an internal face of the lead-in face. However, since the maximum diameter of the conical lead-in face, opposed to the flange end of the collar, will have a diameter substantially greater than the diameter of the cylindrical collar itself, whereby such maximum diameter will also be greater than the maximum diameter of the aperture formed in the plastic bag so that during manufacture, the collar will be retained from displacement out of the bag during its connection thereto, when the bag is welded to the external surface of the lead-in face.
Since the lead-in face is designed for substantially complimentary engagement with the tapered sides of the bag, such conical lead-in face is preferably inclined relative to an elongate sidewall of the collar at an angle of between 20° and 70° so as to compliment the tapered sidewalls of the bag. Again it is preferable the lead-in face is inclined at an angle of 30° relative to the collar sidewall.
Preferably, the elongate sidewall of the collar will define a first thickness whereby the lead-in face will define a second thickness less than half the first thickness. Where the lead-in face projects into the interior of the bag of the container then its inner end face is required to be of minimum thickness so as to alleviate its interference with powder flowing out of the bag. The thickness of the conical surface can therefore be uniform or may in fact taper from its engagement with the sidewall of the collar to its remote end so as to provide a minimal resistive surface to powder flow.
The container will preferably comprise a support member, extending transversely across the bag in the region of the closed end. The support member allows the bag to be supported in an inverted position without collapsing and will preferably be supported within a sealed pocket at the closed end of the bag. This support member will usually comprise at least one hanging means for engagement with an external fixing so as to mount the container on that external fixing specifically in an inverted position when emptying powder from the container. The hanging means may comprise a projection or, preferably, will comprise a hole extending therethrough for receipt of an appropriate fastening device, such as a hook. By providing the support member within a sealed pocket of the flexible bag, a hook may be passed both through the bag material of such sealed pocket as well as the support member without compromising the integrity of the container. This provides for a simplified and low cost connection system.
A further advantageous feature of the current invention resides in the fact that the material used to manufacture such bags will usually be a clear plastic material and thus the support means may be coloured to provide an appropriate indices for particular use of the bag. For example, where several different chemicals of pharmaceutical products are being transferred in a similar environment, there may be a need to avoid the same bag being used for different materials in case of cross contamination. Use of simple coloured indices could alleviate this potential difficulty.
Whilst the bag may comprise a single layer, it is preferable that the container will utilise a multi-layer bag, usually comprising at least two bags, one disposed within the other. Where a plurality of layers are used in this manner, both or all bags may be welded to either the external or internal surface of the conical lead-in face of the collar or, alternatively, the innermost layer of the bags may be welded to the inner face of the lead-in surface whereby the outermost layer of the bag may be welded to the exterior surface of the lead-in face. This would serve to further reduce interference of the lead-in face with powder flow out of the bag. The use of multiple layers also increases the integrity and strength of the container, especially if one layer should fail or be perforated.
The collar of the container may itself comprise a valve mechanism for selectively opening or closing the aperture therethrough, whereby such a valve mechanism would be formed partway along the elongate length of the collar. By providing a valve member integral with the collar, the possibility of product spillage is significantly alleviated since the valve will remain closed until the collar is connected to an appropriate container to which the powder is to be transferred.
The container may optionally further comprise a releasable cap member for sealable engagement with the collar, thereby effecting sealing of the powdered material therein. It is preferred for such cap member to comprise a circular plastic disc so as to effect complimentary engagement with the cylindrical collar, such cap member usually provide or associated with a resilient gasket member for compression between the cap member and the collar to effect such sealing engagement therebetween, wherein a clamp member is preferably employed for clamping the cap member to the collar so as to compress the gasket therebetween.
Further according to the present invention there is also provided a method of manufacturing a powder container from a tubular plastic material, comprising the steps of welding at least two opposed seams, each inclined relative to a longitudinal axis of the tube, along a part of said tubular plastic material to form a tapered bag having a first opening at one end of said tube with a width less than half the maximum width of the tube; further placing a plastic collar into engagement with the bag so as to engage the bag about this first opening and then inserting a first press tool into the bag, through a second opening, at an end remote from the first opening and subsequently compressing the bag and the collar between this first press tool and a second press tool external of the bag, whereby at least one of the press tools are heated so as to form an appropriate weld between the bag and the collar under pressure, finally removing the first press tool from the bag and welding a closure seam across the remote end of the bag.
Usually, this method further provides the step of sealing the bag at its end remote from the first opening by forming two welded seals so as to form a pocket at this remote end, wherein a support member is positioned between these two seals so as to be retained within the pocket.
Preferably, the collar will have a tapered lead-in face so as to be placed into engagement with the bag by inserting the collar into the bag from an end remote from the opening, causing an external surface of the lead-in face to engage an internal surface of the bag about said opening, thereby supporting the collar within the bag during the manufacturing process.
There will now be described, by way of example only, a preferred embodiment of the present invention with reference to the following illustrative drawings in which:
Figure 1 is a cross sectional view through a powder container according to the prior art; and
Figure 2 is a front view of a powder containment bag according to the present invention; and
Figure 3 is a perspective view of a collar of the containment bag of Figure 2; and
Figure 4 is a cross sectional view of the collar of Figure 3 along the lines IV-IV; and
Figure 5 is a perspective view of the containment bag of Figure 2; and
Figure 6 is a schematic illustration of a pharmaceutical reactor employing the use of the containment bag of Figure 2; and
Figure 7a shows a locking clamp for use with the containment bag of Figure 2; and
Figure 7b is a cross sectional view of the containment clamp of Figure 7a connecting the collar of the containment bag of Figure 2 with a reactor inlet/exit port; and
Figure 7c is a partial cross sectional view of a sealing cap secured to the collar of Figure 4; and
Figure 8 shows an alternative powder container according to the present invention; and
Figure 9 is a schematic illustration of an alternative design of containment bag according to the present invention.
Referring now to Figure 1, a powder container (10) according to the prior art is shown. This container (10) comprises a substantially hollow drum made of moulded plastic material, usually high density polyethylene (HDP). Alternatively such drums may also be manufactured from stainless steel, especially when used in the pharmaceutical industry. Such a device will have a wall thickness of between 4mm and 10mm so as to form a substantially rigid structure and comprises a cylindrical main section (12) of uniform diameter, extending from a sealed base (14). An end (16) of the container opposed to the base (14) is provided with a circular aperture (18) which is formed coaxial with the drum axis (A). The aperture (18) is formed within a circular flange (22) supported on a cylindrical collar (20) also mounted coaxial about axis (A). The diameter of the collar (20) is significantly less than the diameter of the main section (12) and the container (10) is therefore provided with a conical wall portion (24) extending between the main body portion wall (12) and the collar (20).
The flange (22) is provided with an external rim (26) for co-operation with appropriate clamping mechanism for connecting the container (10) to an inlet valve or outlet valve of a material handling device to allow transfer of material to or from the container. The flange (22) is further provided with an internal circular flange portion (26) extending radially inwardly of the collar (20), forming an internal lip around the interior surface of the collar. This interior lip supports a plurality of projections (30) which serve as an alignment mechanism with appropriate apertures in either a lid or connector to which the container (10) is to be secured.
Whilst containers of this type provide for appropriate storage and transportation of powdered materials, their inherent strength and rigidity mean that when not in use they occupy a large volume of storage area, whereby their weight, resulting from the thickness of material required to give appropriate support strength, can make such containers difficult to handle, especially when fully laden. Also, the high costs of such drums (due to both material content and manufacturing processes) makes their re-usability an inherent necessity so as to appropriately amortise such cost. However, to avoid the possibility of cross contamination of residual powder content, such drums also require a costly cleaning process after each usage, again rendering their use expensive.
Furthermore, whilst the conical surface (24) ensures that powdered material within the container (10) is able to flow freely towards the aperture (18) when the container is inverted so as to empty the powder therefrom, the formation of the inner lip (26) of the flange (22) creates a shoulder restricting flow of powder past this flange when the container is being emptied. Where such powdered material is comparatively expensive, ie. the pharmaceutical industry, then the resultant potential loss of material by being trapped on such lip can be costly when considering the number of containers used during a normal production run.
One final drawback of the prior art device results from its difficulty in manoeuvrability and handling the devices into an inverted position so as to empty the contents therefrom. When emptying such containers into an appropriate reactor vessel during a manufacturing process, the container (10) needs to be inverted and connected to an appropriate inlet on the reactor. Due to the inherent weight of the product itself and its bulky shape, it can be relatively difficult to manoeuvre this product to an inverted position and maintain it in sealed engagement with the reactor, requiring complex and expensive support mechanisms on the reactor itself. Also, since such containers are rigid, this prevents an operator from being able to externally access and manipulate any powder therein which could assist powder flow, particularly if the powder became damp.
The difficulties with the prior art containers of this type are now addressed by the current invention shown in Figure 2.
Figure 2 shows a container (38) which comprises a flexible plastic container in the form of a collapsible bag (40), preferably manufactured of a blend of low density polyethylene and linear low density polyethylene with 1.0% anti static and 0.5% slip additives. It is preferable that the bag is made of a mono plastic to provide for ecological benefits in its disposal. The bag (40) is welded to a substantially rigid plastic moulded collar (42) to be maintained in sealed engagement with this collar.
Referring to Figures 3, 4 and 5, the collar (42) itself comprises an elongate cylindrical portion (44) defining a cylindrical aperture (46) therethrough. At one end of this cylindrical portion (44) is formed a radially extending circular flange member (48) and, at its longitudinally opposed end, comprises a conical lead-in face (50) having an increasing diameter in a direction away from the flange (48). This collar (42) is also usually manufactured from the same material as the bag and is formed by injection moulding.
Whilst the plastic material used in the manufacture of this particular type of container provides for ecological benefits in its disposal, it also meets the approval of the European Community and United States Plastics Migration Legislation, which legislation limits the plastics material that can be used, particularly in the pharmaceutical industry, to those materials having minimal migration of contaminates out of such plastic material in use. This is of specific importance in the pharmaceutical industry whereby the purity of the pharmaceutical products must be maintained throughout the handling process as well as the manufacturing process.
In addition, and as can be clearly seen from the cross sectional view shown in Figure 4, the wall thickness of the cylindrical portion (44) of the collar (42) is considerably greater than the conical lead-in face (50) whereby the wall thickness of the cylindrical portion is preferably in the region of 4mm to 8mm and of constant thickness, with a preferred thickness of 5.33mm. The wall thickness of the conical portion is in the region of 1mm to 3mm thick and preferably 1.65mm thick.
The cylindrical portion (44) is mounted coaxial with a container axis X (refer to Figures 2 and Figures 4) so that its sidewalls are parallel to such axis, whereby the conical lead-in face (50) is also mounted coaxial with this axis and inclined at an angle α of between 20° and 70° with a preferred angle α of 30°.
The circular flange (48) presents a substantially flat surface (52) in an outwardly facing axial direction, and has a circular groove (54) extending coaxial with axis X in said surface (52). In cross sectional profile, this groove (54), is semi circular, and forms a gasket rebate as will be discussed below. The rear surface (56) of the flange (48) (axially opposed to the flat surface (52)) is axially inclined from the outer edge of the flange towards the cylindrical member (44) so as to form a second conical surface (56). The particular flange design is conventional for use in the pharmaceutical industry and will be described in more detail with reference to Figures 7a and 7b below.
As is conventional for the manufacture of such flexible plastic bags, the polyethylene material is supplied as a conventional cylindrical tube as the result of its manufacturing process. This cylindrical tube is flattened so as to form an elongate strip whereby a conventional plastic weld tool is then employed to form two axially inclined weld seams (60) by welding together the opposed surfaces of the tubular polyethylene material. Such welding technique is conventional and employs the application of pressure and heat so as to melt and squeeze together the melted polyethylene to form such secure seals. The remaining excess material of the tubular polyethylene (shown schematically as (62) in Figure 2) is then removed by an appropriate cutting device. By forming two seals (60) as shown in Figure 2, the bag (40) comprises a main body portion (64) having a maximum width W and having a tapered region defined by the seals (60). The two welded seals (60) are formed symmetrically about a central axis X of the bag (40), as shown, and taper inwardly at angle (3 with respect to such axis X at an angle β of preferably 30°, although it will be appreciated that this angle β can vary between 20° and 70° as appropriate.
The inclined weld seals (60) therefore define a reduced width opening in an end of the bag (40) whereby the width of this opening, W1 (Figure 2) is significantly less than the maximum width W of the bag (40) and is preferably less than half the width W. In this embodiment, W1 is approximately one third of W.
During manufacturing of the bag (40), at this stage the end of the bag (70) longitudinally opposed from and remote from the tapered end remains open, allowing the collar (42) to be inserted into the bag (40) and for the flange (48) and cylindrical portion (44) to pass through the reduced width aperture defined between the two tapered seals (60). However, the conical portion (50) of the collar (42) has a greater maximum diameter than the opening formed in the bag and thus the collar (42) is restrained from passing out of this aperture. In this position, since the angle α of the conical lead-in surface of the collar (42) and the angle β of the bag (40) are preferably similar and set ideally at 30° then the exterior surface (51) of the conical surface (50) abuts the interior surface of the bag (42) in close fitting engagement. An appropriately shaped conical first press tool is then also inserted into the bag so as to engage the interior surface (53) of said conical portion (50) of the collar (42) in a complimentary fit so as to support this rear surface (53). A second, exterior, weld tool is then brought into complimentary engagement with the exterior surface of the bag (40) in the region of its engagement with the collar (42) so as to compress the bag (40) and the conical portion of the collar (42) therebetween and one or both of the press tools is provided with an appropriate heat source so as to effect welding of the plastic material of the bag and the conical portion (50) of the collar (42), under pressure, in a conventional operation. Preferably, two radially extending welds (45) are formed extending coaxial with axis X.
Subsequently, the welding tools are removed from the bag (40) which is then sealed at its remote end (70) by a further welding process.
The final, closure welding, of end (70) is effected by a dual sealing process so as to form in a sealed pocket (75) at the remote end (70) of the bag. The welding operations are achieved by conventional means of compressing the bag between two elongate sealing members which are then heated so as to melt and compress the melted regions together. The first seal (77) isolates the pocket from the main portion of the bag (40) and a substantially rigid elongate plastics support member (79) is inserted into the pocket (75) before the second seal (81) is achieved. In this embodiment, the second seal (81) is profiled with tapered edges. The support member (79) is elongate and extends transverse to the axis X. Thus, whilst the bag (40) is able to collapse in an axial direction, support member (79) adds rigidity to maintain the transverse shape of the bag as shown in Figure 2. Furthermore, the support member (79) is provided with a circular aperture (83) therethrough to allow this support member to be connected to an appropriate hook or other projection where appropriate, as will be described later.
Whilst the foregoing description describes a single layer bag, it is preferable that the container (38) be provided with a dual layer bag which is simply formed of two concentric tubular plastic bags which are welded together by the appropriate welding stages previously described in forming the weld seals (60) and those welding the bags with the collar (42). Here both bag layers are again welded to the outer surface (51) of the conical portion of the collar (42). The use of two (or if required three or more layers) provides for additional integrity of this type of containment bag whereby should the outer layer be ripped or damaged then the integrity of the storage device is maintained by the second layer. However, it is also envisaged that the invention resides in the use of a single layer bag where such integrity is of reduced importance (for example in lower cost powder transportation), such as sugar.
Referring now to Figure 6, use of the containment bag (38) of the present invention is now described. Within the pharmaceutical industry in particular, powdered materials forming the basis of the drug are considered a staple manufacturing component. The transportation of storage of such powdered material is of high importance due not only to the expense of the material itself but to its hazardous nature whereby the release of high volumes of powdered pharmaceutical material could prove hazardous if inhaled or handled.
The current invention thus allows for safe storage and transportation in such environment. As shown in Figure 6, the containers (38) are used for transferring pharmaceutical powders, primarily, to and from an appropriate reactor vessels (100). Such reactor vessel will usually be supported between two floors of a building whereby such a floor is illustrated schematically in Figure 6 by reference (102). The design of the reactor is irrelevant to the current invention save to mention that it is used for mixing appropriate powdered pharmaceutical materials. In practice, such reactor vessels (100) will have a plurality of input ports (104) with appropriate releasable valve mechanisms ensuring that such input ports (104) remain closed until such time that an appropriate container is connected thereto. Similarly, the reactor vessels will comprise at least one outlet port (106) allowing the mixed materials to be removed from the reactor. Again the outlet port (106) will also have a releasable control valve to maintain the integrity of the vessel until such time that an appropriate container is connected thereto to collect material to be removed from the reactor vessel. Connection between the containment bag (38) and the inlet/outlet port (104, 106) will be described below with reference to Figures 7a and Figure 7b but the connection is effectively airtight preventing release of the powdered material into the atmosphere during transfer from the reactor to the containment bag and vice versa.
In practice, when powdered material is to be inserted into the reactor through an input valve (104) an appropriate hook member (108), mounted on an appropriate gantry (110), is used to engage the support member (79) of the containment bag (38). The hook member (108) is able to perforate the sealed pocket (75) without compromising the integrity of the powder conveying portion of the bag (40) and is thus able to pass through the aperture (83) in the support member (79) and pass out through the opposite side of the bag (38). This provides for an efficient and cost effective means of hanging the bag (38) in an inverted position without the need for providing complex support mechanisms to support the major surface of the bag (38). The containment bag (38) will, during this inversion process, be sealed by an appropriate releasable valve mechanism connected to the collar (42) (as will be described in Figure 7a and Figure 7b below). Once inverted and mounted on the gantry (110) the collar will be sealably connected to the input valve (104) with the appropriate control valves then opened to allow the product to flow from the bag (38) into the reactor vessel (100) in a conventional manner. Since the weld seal (60) of the bag (38) provides an appropriate inclined lead-in surface towards the collar (42), no shoulders are provided within the interior surface of the bag against which the pharmaceutical material could collect during this product transfer. Furthermore, since the conical surface of the collar is disposed in close fitting abutment with this interior inclined surface of the bag (40) then the effect of an end face of this conical portion (42) on powder flow in this inverted position is significantly reduced. Such effect is further reduced by the reduced wall thickness of the conical portion (42) and the fact that the bag (40) is welded in close proximity about the entire circumference of the collar. As such, the current containment bag design allows the powdered product to freely flow out of the bag with little or no product retention therein. Since the bag itself is of a flexible plastic material, it also allows an operator to, if necessary, manipulate the contents thereof so as to assist powder flow. This is particularly useful if the bag content becomes damp or powder is retained in any crease or fold within the bag.
Once the bag has been emptied, due to its collapsible nature and the lightweight materials used, it is readily reduced in overall size for storage until subsequently required. Its lightweight material also makes for ease of handling.
Again with reference to Figure 6, the bags (38) are also engageable with the outlet port (106) to collect and store powdered material output from the reactor (100). In this manner, the bags (38) are again connected, via substantially airtight seals, with the output valve (106) but, in this situation, are housed within appropriate steel or plastic bins (112) to provide additional strength to the bag when collecting the powdered material. However, the use of such bins (112) is optional. The valves of the outlet port (106) can then be opened to allow the flow of powder into the bag under gravity.
Referring now to Figure 7a and Figure 7b, the connection system used with this type of collar and flange will now be described. The containment bags (38), once filled, may be sealed with a cap member, where appropriate, for long term storage.
Alternatively, the filled containment bags (38) will have a releasable valve member connected thereto which provide an appropriate temporary seal when the bags are remote from the reactor but, when the valve members are then subsequently connected at their free end to an appropriate input or output valve of a reactor, the valve can be opened to allow product to flow from the bag to the reactor. Such valve connectors whilst expensive, are readily employed within the pharmaceutical industry where it is usually important for such powder containers to remain sealed during transportation, storage and product transfer even over short distances or time periods. In practice, the connectors of the valve means or caps to which the collar (42) is to be connected will comprise the same configuration as the collar itself, each having a substantially cylindrical tubular portion with a correspondingly shaped flange. This is illustrated in Figure 7b whereby the flange (48) of the collar (42) abuts a corresponding and identical flange (48') of a device (49) such as either a cap member, a valve member or an input/output valve of a reactor. An appropriate resilient gasket (120), usually rubber or plastic, comprising a circular disc (121) and tubular portion (122) is disposed between the two flanges (48, 48') such that the tubular portion (122) is received in a complimentary fit within the semi-circular rebates (54, 54') of each flange to be compressed therebetween. A clamp member (150) (as shown in Figure 7a) is then used to clamp the two flange members (48, 48') in this sealed engagement. The clamp member (150) comprises a hinge (152) about which are pivotally mounted two semi-circular engagement arms (154, 156) and which engagement arms can be locked together by use of an appropriate locking mechanism, shown generally at (160). With reference to Figure 7b, showing a cross sectional view of the clamp (150), each of the engagement members (154, 156) have two opposed and inclined engagement faces (160) for complimentary engagement with each conical surface (56) on the rear of the flanges (48, 48') respectively as shown in Figure 7b. In practice, the two flanges are brought into engagement as shown, whereby the two engagement members (154, 156) are then pivotally brought into engagement so as to surround these engaged flanges, and are then locked together by the appropriate mechanism (161). This mechanism (161) is further provided with means to not only lock together the two engaged arms (154, 156) but to compress these engagement means towards one another so as to reduce the overall diameter of the clamp (150), whereby the reduction of such diameter forces the engagement members towards one another resulting in cam engagement between the inclined surfaces (160) and the conical surfaces (56) of the appropriate flanges. This cam engagement serves to compress the two flange members towards one another and to compress the gasket (120) therebetween to form an appropriate air tight seal. This type of locking mechanism is considered conventional within the pharmaceutical manufacturing industry and is provided by way of example only.
Whilst it is preferable that the containment bag (38) is sealable by connection of an appropriate double ended valve member (one end of which may be connected to the bag as described with reference to Figure 7b and the other end which may be connectable to an input or output port of an appropriate reactor vessel) such that the valve connector can be opened or closed as appropriate to either retain the bag as sealed or to allow product to flow into or out of the bag when connected to an appropriate vessel, it is also envisaged that an appropriate valve mechanism can be readily incorporated into the tubular portion of the collar (42) if this portion is increased in length, whereby a conventional valve mechanism can then be readily integrated into this collar design which will be provided for opening or closing such valve as appropriate. This would remove the need for an intermediate valve member and clamping mechanism to connect it to the containment bag.
In many industries, particularly the pharmaceutical industry, it is necessary for the contents of the bags to be sealed therein as they are moved between connections to a reactor or other type of conduit. However, the dual ended valve mechanisms employed so as to provide a means of both sealing the containment bag and allowing its removal from an appropriate reactor without exposing the contents to the atmosphere, are expensive and are thus inefficient for long term storage of product within containment bags. It is therefore an enhancement of the current invention to provide an appropriate cap mechanism for sealing such containment bags for storage purposes, thereby negating the requirement for a large number of expensive valve mechanisms which would otherwise be expensively employed for storage purposes. Referring now to Figure 7c, a plastic cap member (410) is shown in part cross section, which cap member comprises a simple circular disc (again made from the same plastic material as both the collar and the bag). Again such cap will be plastics moulded and will have formed in its lower surface (412) and annular rebate (414) for receipt of a tubular portion (122) of an appropriate resilient gasket (120) of the same type utilised when connecting the collar to the valve member as shown in and discussed with reference to Figure 7b.
In this particular embodiment of cap (410), its upper surface (416) is flat so as to lie parallel to the lower surface (412) (as shown in Figure 7c) and differs from the valve shown in Figure 7b in that it is not provided with an inclined clamping surface. Again, a similar clamp member (450) is then used to clamp the lid (410) to the flange member (48) of the collar (42) in a similar manner to use of the clamp member (150) for clamping the valve mechanism thereto as shown in Figure 7a. The clamp mechanism (450) again comprises two pivotally mounted semi-circular engagement arms (one of which is shown in Figure 7c) so as to engage and receive, within a channel (452) thereof, the cap (410) and the flange (48). Since the upper surface (416) of the cap (410) is substantially flat, then one of the inwardly extending side walls (454) of the clamp (450) is of complimentary flat configuration, whereas its opposed wall (456) is inclined for complimentary cam engagement with the conical surface (56) of the collar flange as the clamp (450) is compressed radially inwards in the direction indicated by the arrow (460) in Figure 7c. The resultant compressive force exerted by the wall (454) of the clamp on the cap towards the flange (48) compresses the gasket (120) therebetween and serves to provide an appropriate sealed engagement between the cap and the containment bag, providing for an inexpensive means for sealing such bags for storage.
Within the pharmaceutical industry it is desirable to restrict exposure of the pharmaceutical product contained within the bag, and the valve mechanism as described in reference to Figure 7b will be used to seal the bag as it is removed from the reactor and until it is placed in an appropriate sealed glove box (isolated and sealed chambers allowing contents placed therein to be manipulated by a user located outside of such chamber by the use of gloves extending thereinto). Replacement of the valve mechanism with the cap member (410) can then be simply undertaken in a sealed environment. Once the cap has been attached thereto, the containment bag with its contents can then be safely stored. Similarly, when the contents of the bag are required, the container may be returned to the glove box whereby the cap member is accordingly replaced with an appropriate valve mechanism for connection with an appropriate reactor.
The specific design of the flange (48) used with the collar of the preferred embodiment is one of several possible variants and it is important to note that the current invention is not limited to the specific design of flange mechanism used for connecting either the cap or an appropriate valve mechanism to the collar. The specific flange (48) described herein is by way of example only.
It will be appreciated that the foregoing description was by way of example only describing one preferred embodiment. Variations to the basic inventive concept, whilst still falling within the scope of the current invention, will now be discussed.
In particular, whilst the preferred embodiment utilises welding the bag (40) to the exterior surface (51) of the conical lead-in face (50), the current invention is equally applicable where the plastic bag (40) will be welded to the interior surface (53) of such conical member. In this situation the collar is firstly positioned adjacent to the exterior of the bag (40) during manufacture so that the tapered end of the bag lies adjacent to this interior surface (53). An appropriate weld tool is again introduced into the interior of the bag, as previously described so as to compress the bag against the conical surface (50) and a second, exterior, press tool engages the outer surface (51) of the collar to compress the bag and collar between the two conical press tools which are then plastics welded in a conventional manner. The added advantage of welding the bag to the collar in this manner will be to alleviate the formation of a lip on the interior inclined surface of the bag (resulting from the end surface of the lead-in face (50)). It is also possible that where a dual membrane bag system is employed (using two concentric bags as previously described) then a first, outer bag, could be welded to the outer surface (51) of the conical surface (50) as previously described with a second welding operation to weld the interior bag to the inner surface (53) as described above. Both bags could also be welded together, with a coaxially extending radial weld, adjacent to this conical surface (50). Here a dual stage manufacturing process would be required whereby a single layer bag according to the preferred description would firstly be constructed then a second bag could be formed and inserted into the first bag so as to be welded against the inner surface (53) of the conical surface with an additional welding operation to also weld the bags together at at least one point adjacent to the collar. This would provide an additional advantage in that the outer bag opening would restrain and support undue load on the collar in use whereby the inner bag, containing the powder, would not be inhibited by any part of the collar extending thereinto.
Alternatively, where the bag (40) is welded to the exterior surface of the conical lead-in face (50), the thickness of this lead-in surface (50) could be tapered so as to reduce in thickness as it extends away from the cylindrical portion (44) thereby further alleviating any impact on product flow that this narrow conical portion may have.
A further enhancement in the current invention would be the provision of different coloured support members (79). For example, in use in the pharmaceutical industry considerable volumes of chemicals and pharmaceutical products are transported using such containment devices and, to prevent the possibility of cross contamination, by avoiding use of the same containment bag, inadvertently, for different chemical products, a colour coded system could be readily employed by the provision of different coloured support bars (79).
Also, with reference to Figure 8, whilst the preferred collar (42) shown and described with reference to Figures 2 through 5, utilises a conical lead-in face to which the tapered bag can be welded, the current invention is also applicable to a collar which does not have a conical lead-in face, but may, in fact, simply have a radially extending connector (250) as shown in Figure 8. Again the collar (242) as shown in Figure 8 has a similar flange (248) to that shown in Figure 4, wherein here it is simply provided with a radial extending surface (250) to which the tapered bag (40) can be welded in a conventional manner. Alternatively, the reduced aperture of the bag (40) can be welded directly to the flat radially extending flange (251) of this collar (242) by appropriate design of the welding tool. However it is preferred to use a conical surface (50) as described within the preferred embodiment as this provides for additional support of the bag (40) in the region of the collar.
Finally, whilst the preferred embodiment herein described is with reference to a substantially tubular bag (40), the current invention is equally applicable to bags of different geometric design. For example and as shown in Figure 9 the bag (338) could in fact be formed so as to be substantially square/rectangular whereby, in a manner to that previously described, appropriate seals can be welded into a conventional tubular plastic material whereby the array of appropriate welded seals (300) will create appropriate tapered faces (302) tapering inwardly from the periphery of the substantially square bag to engage with a square or rectangular collar shown schematically in Figure 8b as (310). Such a square collar would also have appropriately inclined rectangular lead-in faces for complimentary engagement with the tapered side faces (302) of the bag (338) in the manner similar to that described with reference to the conical arrangement in Figures 2 through 5. Similarly, a triangular containment bag could also be provided with an appropriate triangular collar design, whereby the key feature here being the inclined nature of the bag from its maximum width to the collar providing an inclined or tapered containment bag.

Claims

A container for storing or transporting powder, said container (38) comprising an elongate deformable bag (40) having a closed end and a longitudinally opposed open end, which open end defining an aperture therethrough that is less than half the maximum width of said bag, said side walls of the bag tapering inwardly between said maximum width to said aperture, characterised in that the aperture is supported and defined by an elongate sealable collar (42) connected to the bag (40), the collar having a flange (48) on a free end thereof remote from the bag (40) that is shaped to receive a complimentary shaped coupling flange (48'), of a device (49) to be connected to the bag (40), a sealing gasket (120) for effecting for a seal between the flange (48) and the flange (48') of the device (49) and clamping means (150) for clamping the flanges (48) and the (48') together to form an airtight connection between the device (49) and the bag (40).
A container according to claim 1 wherein the flanges (48), (48') have confronting planar surfaces and confronting grooves, and the sealing gasket (120) comprises an annular member (120) having a planar portion that contacts the planar faces of the flanges (48), (48') and a raised portion (120).
A container as claimed in claim 1 or claim 2 wherein said tapered side walls of said bag are inclined relative to a longitudinally extending axis of said bag at an angle of between 20° and 70°.
A container as claimed in any one of claims 1 to 3 wherein said collar (42) is cylindrical.
A container as claimed in any one of the preceding claims wherein said collar comprises a conical lead-in face (50) for complimentary engagement with the tapered sides of said bag (40) in the region of said aperture (40).
A container as claimed in claim 5 wherein said conical lead-in face (50) is inclined relative to an elongate side wall of said collar at an angle of between 20° and 70°.
A container as claimed in claim 6 wherein said conical lead-in face (50) is inclined relative to an elongate sidewall of said collar (42) at an angle of 30°.
A container as claimed in claim 5 or in either claim 6 or claim 7 when appended to claim 5 wherein an elongate side wall of said collar (42) defines a first thickness and said lead-in face (50) defines a second thickness less than half said first thickness.
A container as claimed in any one of claims 5 to 8 wherein said bag (40) is secured to an external surface of said conical lead-in face (50).
A container as claimed in any one of the preceding claims wherein said bag comprises a support member (79) extending transversely across said bag (40) in the region of said closed end (70).
A container as claimed in claim 10 wherein said support member (79) is supported within a sealed pocket (75) of said bag (40) at said closed end (70).
A container as claimed in claim 11 wherein said support member (79) comprises at least one hanging means (83) for engagement with an external fixing so as to mount said container (38) on said external fixing.
A container as claimed in claim 12 wherein said hanging means (83) comprises an aperture (83) through said support member.
A container as claimed in any one of claims 10 to 13 wherein said support member (79) is coloured to provide a visible indice.
A container as claimed in any one of the preceding claims comprising a multi layer bag (40).
A container as claimed in claim 15 comprising at least two bags (40), one disposed within the other.
A container as claimed in claim 16 wherein at least one bag is connected to an inner surface (51) of said collar (42) and at least one bag is connected to an outer surface (53) of said collar (42).
A container as claimed in any one of the preceding claims wherein said bag (40) and said collar (42) are formed of plastics material.
A container as claimed in any one of the preceding claims wherein said device (49) comprises a valve mechanism for selectively opening or closing said aperture.
A container as claimed in claim 19 wherein said valve mechanism (49) is formed partway along said elongate length of said collar (42).
A container as claimed in any one of claims 1 to 18 wherein the device (49) comprises a releasable cap member for sealable engagement with said collar.
A container as claimed in claim 21 when appended to claim 3 wherein said cap member (49) comprises a circular plastic disc.
A container as claimed in either claim 21 or claim 22 wherein said cap member (49) further incorporates the resilient gasket member (120) for compression between said cap member (49) and said collar (42) to effect sealing engagement therebetween.
A container as claimed in any one of claims 21 to 23 wherein clamp member (150) is provided for clamping said cap member (49) to said collar (42).
A method of manufacturing a powder container (38) from a tubular plastics material comprising the steps of
welding at least two opposed seams (60), each inclined relative to a longitudinal axis of said tube, along a part of said tubular plastics material to form a tapered bag having a first opening at one end of said tube with a width less than half the width of said tube;
placing a plastics collar (42) into engagement with said bag so as to engage said bag about said first opening;
inserting a first press tool into said bag (40) from an end remote from said opening (46);
compressing said bag (40) and said collar (42) between said first press tool and a second press tool external of said bag;
heating at least one of said press tools so as to weld said bag (40) to said collar (42) under pressure;
removing said first press tool from said bag (40) and welding a closure seam across said remote end (75) of said bag (40).
A method as claimed in claim 25 comprising the steps of sealing said bag (40) at an end (75) remote from said first opening (46) two welded seals so as to form a pocket at said remote end, wherein a support member is positioned between said two seals so as to be retained within said pocket.
A method as claimed in claim 25 or claim 26 wherein said collar (42) has a tapered lead-in face (50) and is placed into engagement with said bag (40) by inserting said collar (42) into said bag (40) from an end (75) remote from said opening (46), causing an external surface (53) of said lead-in face to engage an internal surface of said bag about said opening (46) .