The present invention relates to methods and systems for forming moulded receptacles from a fibre suspension, such as a fibre suspension comprising paper pulp. The receptacles may form consumer packaging, such as bottles, useful for holding liquids, powders, other flowable materials or solid objects.
It is desirable to reduce plastics use in consumable items, particularly packaging. Trays and other simple shapes are commonly made from a fibre suspension, such as, in particular, a fibre suspension comprising paper pulp. However, more complex objects, such as bottles, are more difficult to engineer.
In certain existing methods for manufacturing objects from fibre suspension(s), such as a fibre suspension comprising paper pulp, an object is formed by introducing fibre suspension into a mould, so as to form a fibre-containing layer within the mould. In such manufacturing methods, a particular challenge is to achieve relatively even and complete coverage of the mould by the fibre-containing layer. Incomplete coverage can, for example, lead to the final object being misshapen or containing voids, whereas uneven coverage can, for example, lead to the final object having weak points that are more prone to rupture or breakage during use of the object.
To mitigate the issues identified above with achieving a relatively even and/or complete coverage of a mould by a fibre-containing layer, and/or to mitigate other issues connected with the formation of moulded receptacles from a fibre suspension, the inventors propose to deposit fibre suspension during two deposition periods that are separated by an intervening pressure build-up period. During this pressure build-up period, a negative pressure of increasing magnitude is generated within the cavity of the mould. This encourages the fibre suspension that is deposited during the second deposition period to accumulate at locations within the cavity where less of (or none of) the fibre suspension deposited during the first deposition period is present. Consequently, the overall effect of the two depositing periods is to provide a fibre-containing layer with relatively even and complete coverage of the mould.
Therefore, according to a first aspect of the present invention, there is provided a receptacle moulding system for moulding a receptacle from a fibre suspension, the system comprising: a mould comprising one or more internal surfaces that define a cavity, and a plurality of passageways that provide fluid communication between the cavity and an exterior of the mould; a fibre suspension supply system; a negative pressure source, configured to apply negative pressure to the exterior of the mould; and a control system, configured to control the fibre suspension supply system and the negative pressure source such that: during a first deposition period, a first volume of a first fibre suspension is deposited by the fibre suspension supply system within the cavity of the mould; during a second deposition period, a second volume of a second fibre suspension is deposited by the fibre suspension supply system within the cavity of the mould, while the negative pressure source applies negative pressure to the exterior of the mould; and during a pressure build-up period, which is after the first deposition period and before the second deposition period, the negative pressure source applies negative pressure to the exterior of the mould, while the fibre suspension supply system restricts deposition of the first and second fibre suspensions within the cavity, thereby generating a negative pressure of increasing magnitude within the cavity.
Because a negative pressure of increasing magnitude is generated within the cavity during the pressure build-up period, when the second volume of second fibre suspension is then deposited, the second fibre suspension may preferentially accumulate at locations within the cavity where less of (or none of) the first fibre suspension is present. Consequently, the thus-deposited second volume of the second fibre suspension in combination with the first volume of the first fibre suspension may together provide a deposited fibre layer that better covers the internal surfaces defining the cavity and/or has a relatively uniform thickness.
In some examples, the negative pressures applied by the negative pressure source and generated within the cavity may be negative gas pressures. For example, the negative pressures may be negative air pressures, particularly where the mould is in air during the first and second deposition periods and the pressure build-up period.
Optionally, the mould is porous, with the passageways being provided at least in part by a plurality of pores in the mould.
Optionally, the pressure build-up period immediately follows the first deposition period and/or immediately precedes the second deposition period.
In some examples, the system is configured so that, as a result of the negative pressure source applying negative pressure to the exterior of the mould during the depositing of the second volume of the second fibre suspension, turbulent flow of the second volume of the second fibre suspension occurs within the cavity. Without wishing to be bound by the theory, it is thought that that turbulent flow may distribute fibres particularly effectively, which may in turn lead to the deposition of a layer of fibres with relatively even thickness.
In some examples, the system further comprises a pressure sensor configured to measure pressure at the mould (for example at the exterior surface thereof, or within the cavity), and the control system is configured to cause the depositing of the second volume of the second fibre suspension, by the fibre suspension supply system, once an pressure value, as measured by the pressure sensor, falls below a predetermined negative threshold value. The pressure measured at the mould is considered a particularly suitable trigger for the depositing of the second volume of the second fibre suspension, as it may indicate that the second volume of the second fibre suspension will be drawn with appropriate force into the cavity. This may, in consequence, increase the likelihood that an even layer of fibre is formed within the cavity. Alternatively, or additionally, the depositing of the second volume of the second fibre suspension occurs once negative pressure has been applied to the exterior of the mould for a predetermined period of time during the pressure build-up period.
In some examples, the control system is configured to control the fibre suspension supply system such that, throughout the pressure build-up period, no deposition of any fibre suspension takes place in the cavity.
In some examples, the control system is configured to control the fibre suspension supply system such that: during the first deposition period, the first fibre suspension is introduced into the cavity at a first rate and, during the second deposition period, the second fibre suspension is introduced into the cavity at a second rate; and during the pressure build-up period, the fibre suspension supply system restricts deposition of the first and second fibre suspensions within the cavity such that a rate of introduction of fibre suspension into the cavity is less than the first rate and/or less than the second rate. The rate of introduction of fibre suspension during the pressure build-up period (e.g. the average or maximum rate) may be relatively low, such as, for example: less than 20% of the first rate (e.g. the maximum value thereof) and/or less than 20% of the second rate (e.g. the maximum value thereof); or, less than 10% of the first rate (e.g. the maximum value thereof) and/or less than 10% of the second rate (e.g. the maximum value thereof). While the rate of introduction of fibre suspension during the pressure build-up period may be relatively low, it may, in some examples, be greater than zero, so that at least some deposition of fibre suspension occurs during the pressure build-up period.
In some examples, the depositing of the first volume of the first fibre suspension leads to the formation of a first fibre-containing layer on the internal surfaces defining the cavity, and the depositing of the second volume of the second fibre suspension leads to the formation of a second fibre-containing layer on the internal surfaces defining the cavity, wherein the second layer at least partially covers the first layer. Optionally, the second layer covers the majority of, or the entirety of the first layer. Additionally, or alternatively, the first layer covers the majority of, or the entirety of the internal surfaces that define the cavity.
Optionally, the control system is configured to control the fibre suspension supply system and the negative pressure source such that, during the depositing of the first volume of the fibre suspension, negative pressure is applied to the exterior of the mould.
In some examples, the control system is configured to control the negative pressure source such that, throughout a formation period, which comprises the first deposition period, the second deposition period and the pressure build-up period, the negative pressure source applies negative pressure to the exterior of the mould. Optionally, the control system is configured to control the negative pressure source such that, throughout the formation period, the negative pressure source applies a constant negative pressure to the exterior of the mould.
According to a second aspect of the present invention, there is provided a method for manufacturing a moulded receptacle, the method comprising: during a first deposition period, depositing a first volume of a first fibre suspension within a cavity of a mould, the mould comprising one or more internal surfaces that define the cavity, and a plurality of passageways that provide fluid communication between the cavity and an exterior of the mould; during a second deposition period, depositing a second volume of a second fibre suspension within the cavity of the mould, while applying negative pressure to the exterior of the mould; and during a pressure build-up period, which is after the first deposition period and before the second deposition period, applying negative pressure to the exterior of the mould, while restricting deposition of the first and second fibre suspensions within the cavity, thereby generating a negative pressure of increasing magnitude within the cavity.
Because a negative pressure of increasing magnitude is generated within the cavity during the pressure build-up period, when the second volume of second fibre suspension is then deposited, the second fibre suspension may preferentially accumulate at locations within the cavity where less of (or none of) the first fibre suspension is present. Consequently, a deposited fibre layer that better covers the internal surfaces defining the cavity and/or has a relatively uniform thickness may be provided by the thus-deposited second volume of the second fibre suspension in combination with the first volume of the first fibre suspension.
Optionally, the mould is porous, with the passageways being provided at least in part by a plurality of pores in the mould.
Optionally, the pressure build-up period immediately follows the first deposition period and/or immediately precedes the second deposition period.
Optionally, the applying of negative pressure to the exterior of the mould during the depositing of the second volume of the second fibre suspension causes turbulent flow of the second volume of the second fibre suspension. Without wishing to be bound by the theory, it is thought that that turbulent flow may distribute fibres particularly effectively, which may in turn lead to the deposition of a layer of fibres with relatively even thickness.
Optionally, the depositing of the second volume of the second fibre suspension occurs once an pressure value, as measured at the mould (for example at the exterior surface thereof, or within the cavity), falls below a predetermined negative threshold value. The measured pressure at the mould is considered a particularly suitable trigger for the depositing of the second volume of the second fibre suspension, as it may indicate that the second volume of the second fibre suspension will be drawn with appropriate force into the cavity. This may, in consequence, increase the likelihood that an even layer of fibre is formed within the cavity. Alternatively, or additionally, the depositing of the second volume of the second fibre suspension occurs once negative pressure has been applied to the exterior of the mould for a predetermined period of time during the pressure build-up period.
In some examples, throughout the pressure build-up period, no deposition of any fibre suspension takes place within the cavity.
Optionally, during the first deposition period, the first fibre suspension is introduced into the cavity at a first rate and, during the second deposition period, the second fibre suspension is introduced into the cavity at a second rate, and, during the pressure build-up period, the restricting of deposition of the first and second fibre suspensions within the cavity results in a rate of introduction of fibre suspension into the cavity that is less than the first rate and/or less than the second rate. The rate of introduction of fibre suspension during the pressure build-up period may be relatively low, such as, for example: less than 20% of the first rate and/or less than 20% of the second rate; or, less than 10% of the first rate and/or less than 10% of the second rate. While the rate of introduction of fibre suspension during the pressure build-up period may relatively low, it may, in some examples, be greater than zero, so that at least some deposition of fibre suspension occurs during the pressure build-up period.
In some examples, the depositing of the first volume of the first fibre suspension leads to the formation of a first fibre-containing layer on the internal surfaces defining the cavity, and the depositing of the second volume of the second fibre suspension leads to the formation of a second fibre-containing layer on the internal surfaces defining the cavity, wherein the second layer at least partially covers the first layer. Optionally, the second layer covers the majority of, or the entirety of the first layer. Additionally, or alternatively, the first layer covers the majority of, or the entirety of the internal surfaces that define the cavity.
In some examples, the method further comprises, during the depositing of the first volume of the first fibre suspension, applying negative pressure to the exterior of the mould.
In some examples, the method comprises applying negative pressure to the exterior of the mould throughout a formation period, which comprises the first deposition period, the second deposition period and the pressure build-up period. Optionally, the method comprises applying a constant negative pressure to the exterior of the mould throughout the formation period.
In some examples of the systems and methods above, the first fibre suspension is substantially the same as the second fibre suspension.
However, in other examples, the first fibre suspension may be different than the second fibre suspension. In particular, in such examples, an average fibre length of the first fibre suspension may be different than an average fibre length of the second fibre suspension. Optionally, the average fibre length of the first fibre suspension is less than the average fibre length of the second fibre suspension. Without wishing to be bound by the theory, it is thought that that the characteristic average fibre length of a fibre suspension may impact the smoothness of the deposited layer of fibres. Suitable selection of the average fibre length for the first and second fibre suspensions may therefore assist in providing a fibre layer with appropriate characteristics. As an example, a smaller average fibre length for the first fibre suspension may provide a receptacle with a relatively smooth exterior surface. Alternatively, or in addition, a freeness of the first fibre suspension may be different than a freeness of the second fibre suspension. Optionally, the freeness of the first fibre suspension is greater than the freeness of the second fibre suspension. Without wishing to be bound by the theory, it is thought that that the freeness of a fibre suspension may impact how evenly fibres are distributed within the cavity. Suitable selection of the freeness for the first and second fibre suspensions may therefore assist in providing a fibre layer with appropriate characteristics. As an example, a higher freeness may allow the first volume of the first fibre suspension to achieve a relatively even initial distribution of fibres within the cavity.
In some examples of the systems and methods above, the receptacle is a bottle.
According to a third aspect of the present invention there is provided a receptacle obtainable or obtained from a fabrication method comprising any of the above methods for manufacturing a moulded receptacle. For example, the receptacle may be obtainable or obtained from any of the above methods. The fabrication method may comprise at least one additional process. The at least one additional process may comprise further moulding the receptacle to produce a further-moulded receptacle. The at least one additional process may comprise coating and drying the receptacle or the further-moulded receptacle to produce a coated receptacle. The at least one additional process may comprise applying a closure to the receptacle, the further-moulded receptacle or the coated receptacle. In some examples, the receptacle is a bottle.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of embodiments of the invention.
Broadly speaking, the exemplary process comprises providing a fibre suspension, introducing the fibre suspension into a mould cavity of a porous first mould and using the porous first mould to expel a liquid (such as water) from the fibre suspension to produce a wet precursor or embryo (which may itself be considered a moulded receptacle), further moulding the wet precursor in a mould to produce a further-moulded receptacle, coating the further-moulded receptacle to produce a coated moulded receptacle, drying the coated moulded receptacle to produce a dried receptacle, and applying a closure to the dried receptacle. As will be apparent at least from the following description, modifications may be made to the exemplary process to provide variants thereof in which other examples of the present invention may be embodied.
In this example, providing the fibre suspension comprises preparing the fibre suspension from ingredients thereof. More specifically, the preparing comprises providing pulp fibres, such as paper pulp fibres, and mixing the pulp fibres with a liquid to provide hydrated pulp fibres. In this example, the pulp fibres are provided in sheet form from a supplier and the liquid comprises water and one or more additives. In this example, the liquid is mixed with the pulp fibres to provide hydrated pulp fibres having a solid fibres content of 1 wt % to 5 wt % (by dry mass of fibres). In examples, the one or more additives includes a sizing agent, such as alkylketene dimer (AKD). The hydrated pulp fibres typically comprise AKD in an amount of 0.4 wt % with respect to the total dry mass of the solid fibres in the hydrated pulp fibres. In some examples, one or more additives are present in the liquid at the point of mixing the pulp fibres with the liquid. In some examples, one or more additives are included in the hydrated pulp fibres after mixing the pulp fibres with the liquid (e.g. the pulp fibres are hydrated for a period of time, such as from 2 to 16 hours, and then one or more additives are supplied to the hydrated pulp fibres). The hydrated pulp fibres are passed between plates of a valley beater 11 or refiner that are in motion relative to each other. This fibrillates some, or all, of the fibres, meaning that cell walls of those fibres are caused to become partially delaminated so that wetted surfaces of those fibres comprise protruding hairs or fibrillations. These fibrillations will help to increase a strength of bonds between the fibres in the dried end product. In other examples, the valley beater 11 or refiner may be omitted.
The resultant processed pulp is stored in a vat 12 in a relatively concentrated form (e.g. a solid fibres content of 1 wt % to 5 wt %) to reduce a required storage space. At an appropriate time, the processed pulp is transferred to a mixing station 13 at which the processed pulp is diluted in further water and, optionally, mixed with one or more additives (as well as, or in place of, the one or more additives provided with the hydrated pulp fibres) to provide the fibre suspension ready for moulding. In this example, the solid fibres account for 0.7 wt % of the resultant fibre suspension (by dry weight of fibres), but in other examples the proportion of solid fibres in the fibre suspension may be different, such as another value in the range of 0.5 wt % to 5 wt %, or 0.1 wt % to 1 wt %, of the fibre suspension (by dry weight of fibres). In some examples, the one or more additives mixed with the processed pulp and water includes a dewatering agent, such as modified and/or unmodified polyethylene imine (PEI), e.g. modified PEI sold under the trade name Polymin® SK. In some examples, the one or more additives are mixed with the water, and the water and one or more additives subsequently mixed with the processed pulp; in other examples, the processed pulp and water are mixed, and the one or more additives subsequently mixed with the processed pulp and water. The fibre suspension typically comprises Polymin® SK in an amount of 0.3 wt % with respect to the total dry mass of the solid fibres. Mixing of the fibre suspension at the mixing station 13 helps to homogenise the fibre suspension. In other examples, the processed pulp or the fibre suspension may be provided in other ways, such as being supplied ready-made.
In this example, the porous first mould 15 comprises two half-moulds that are movable towards and away from each other, in this case using a hydraulic ram. In this example, each of the half-moulds is a monolithic or unitary tool formed by additive manufacturing (e.g. 3D-printing) that defines a mould profile, and, when the half-moulds are brought into contact with each other, their respective mould profiles cooperate to define the mould cavity in which the wet precursor or moulded receptacle is to be formed. Each half-mould may itself define a smaller moulding cavity and, when brought into cooperation with a second half-mould, the smaller moulding cavities may combine to provide the overall mould cavity. The two half-moulds may themselves be considered “splits” or “moulds” and the overall porous first mould 15 may be considered a “split-mould” or, again, a “mould”. In other examples, the porous first mould 15 may comprise more than two splits, such as three, four or six splits, that cooperate to define the moulding cavity.
In
In one form, in order to remove further suspending liquid (e.g. water) from the embryo, and form or consolidate the three-dimensional shape of the receptacle, an impermeable inflation element 19, e.g., a collapsible bladder, is inserted into the porous mould 15 and expanded to act as an internal high-pressure core structure for the porous mould 15. This process strengthens the wet embryo so that it can be handled, and displaces water from in between the fibres, thereby increasing the efficiency of a subsequent drying process. The inflation element 19 is actuated and regulated using a hydraulic pump 20. The pump 20 has a cylinder that displaces a fluid in a line 21 into the inflation element 19, to expand the inflation element 19 radially and into conformity with the mould cavity. Fluid within the line 21 is preferably non-compressible, such as water. Water also has the advantage over other non-compressible liquids that any leaking or bursting of the bladder 19 will not introduce a new substance to the system (since the suspending liquid is already water, or predominantly water).
Demoulding occurs when the porous mould 15 opens for removal of the self-supporting moulded receptacle 22. Mould cleaning 23 is preferably performed subsequently, to remove small fibres and maintain a porosity of the porous mould 15. In this example, a radially firing high-pressure jet is inserted into the mould cavity while the mould 15 is open. This dislodges fibres from the wall of the mould cavity. Alternatively, or in addition, water from the tank 17 is pressurised through the back of the porous mould 15 to dislodge entrapped fibres. Water is drained for recycling back to an upstream part of the system. It is noteworthy that cleaning is important for conditioning the porous mould 15 for re-use. The porous mould 15 may appear visibly clean after removal of the receptacle, but its performance could be compromised without cleaning.
According to
A drying stage 29 (e.g. a microwave drying process or other drying process) is performed downstream of the thermoforming, as shown. In one example, the drying stage 29 is performed before thermoforming. However, moulding in the mould 25 requires some water content to assist with bonding during the compression process.
The moulded receptacle 22 is then subjected to a coating stage during which, in this example, a spray lance 31 is inserted into the moulded receptacle 22 and applies one or more surface coatings to internal walls of the moulded receptacle 22. In another example, the moulded receptacle 22 is instead filled with a liquid that coats the internal walls of the moulded receptacle 22. In practice, such coatings provide a protective layer to prevent egress of contents into the bottle wall, which may permeate and/or weaken it. Coatings will be selected dependent on the intended contents of receptacle 22, e.g., a beverage, detergent, pharmaceutical product, etc. In some examples, the further drying stage 30 is performed after the coating stage (or both before and after the coating stage). In this example, the moulded receptacle 22 is then subjected to a curing process 34, which can be configured or optimised dependent on the coating, e.g., drying for twenty-four hours at ambient conditions or by a flash drying method. In some examples, e.g. where the further drying stage 30 occurs after the coating stage, the curing process 34 may be omitted.
At an appropriate stage of production (e.g., during thermoforming, or before or after coating) a closure or mouth forming process may be performed on the moulded receptacle 22. For example, as shown in
Reference is now directed to
As shown in
Although, for the sake of simplicity, the control system 80 is illustrated with a single box in
Various features of the mould 15 are also shown in
As may also be seen, in the particular example shown in
In some examples, the negative pressures applied by negative pressure source 70 may be negative gas pressures. Such negative gas pressures may, for instance, be negative air pressures, in particular where moulding of the receptacle 22 using the mould 15 is carried out in air (and thus air is present in the cavity 36 during the first and second deposition periods and the pressure build-up period). However, in other examples such negative gas pressures may not be negative air pressures, for instance where the mould is arranged in a controlled atmosphere during the first and second deposition periods and the pressure build-up period.
Various exemplary features of the fibre suspension supply system 50 are also shown in
Nevertheless, in the specific example shown in
As shown in
As may also be seen from
Reference is now directed to
In general, in the moulding operation shown in
Attention is directed firstly to the first deposition period 102 shown in
In addition, such negative pressure may draw liquid (such as water) out of the fibre suspension, through the passageways 38 of the mould 15. The liquid removed from the fibre suspension/mould 15 may be measured by a liquid measurement system 74 that forms a further part of some examples of system 100. The liquid measurement system 74 may, for example, may comprise the weight scale platform and tank 17 depicted in
In other examples, the first deposition period 102 may end after a predetermined period of time. This period of time could, for example, correspond to a specific amount of fibre suspension being deposited, assuming typical functioning of the fibre suspension supply system 50.
In still other examples, the first deposition period 102 may end when the pressure as measured at the mould (for example at the exterior surface thereof, as depicted in
Attention is directed next to the pressure build-up period 104 shown in
In some examples, the pressure build-up period 104 may end (and/or the second deposition period 106 may begin) when the pressure as measured at the mould (for example at the exterior surface thereof, as depicted in
In other examples, the pressure build-up period 104 may end (and/or the second deposition period 106 may begin) after a predetermined period of time. This period of time could, for example, correspond to a specific negative pressure being attained within the cavity 36, assuming typical functioning of the system 100, including the negative pressure source 70.
Attention is now directed to the second deposition period 106 shown in
It may also be noted that, in the particular example shown, the negative pressure source 70 is active during the second deposition period 106, so that a negative pressure is applied to the exterior of mould 15. This negative pressure may cause the fibre suspension deposited within the cavity 36 during the second deposition period 106 to be suctioned onto the fibre-containing layer deposited during the first deposition period 102 and the internal surfaces 40 of the mould 15. In addition, such negative pressure may draw liquid (such as water) out of the fibre suspension, through the passageways 38 of the mould 15.
As mentioned above, the liquid removed from the fibre suspension/mould 15 may be measured by a liquid measurement system 74 that, in some examples, forms a further part of the overall moulding system 100. In such examples, the first deposition period 102 may, for example, end when the liquid measurement system 74 determines that the weight or volume of the liquid 76 removed from the mould 15 has reached a predetermined amount.
In other examples, the second deposition period 106 may end after a predetermined period of time. This period of time could, for example, correspond to a specific amount of fibre suspension being deposited, assuming typical functioning of the fibre suspension supply system 50.
More generally, by suitable control of the operation of fibre suspension supply system 50, specific volumes of fibre suspension can be deposited within the cavity 36 during the first and second deposition periods 102, 106. For example, the fibre suspension supply system 50 may be controlled to deposit fibre suspension for a specific length of time and/or at a specific rate. The system 100 can therefore be configured, in some examples, to control the fibre suspension supply system 50 so as to deposit equal volumes of fibre suspension during the first and second deposition periods 102, 106, and, in other examples, to control the fibre suspension supply system 50 so as to deposit different volumes of fibre suspension during the first and second deposition periods 102, 106.
Furthermore, although the fibre suspension supply system 50 in the particular example shown in
In particular, it is envisaged that an average fibre length of the fibre suspension deposited in the first deposition period 102 may, in some examples, be different than an average fibre length of the fibre suspension deposited in the second deposition period 106. Without wishing to be bound by the theory, it is thought that that the characteristic average fibre length of a fibre suspension may impact the smoothness of the deposited layer of fibres. Suitable selection of the average fibre length for the fibre suspensions may therefore assist in providing a fibre layer with appropriate characteristics. As an example, a smaller average fibre length for the fibre suspension deposited in the first period 102 may provide a receptacle with a relatively smooth exterior surface.
Alternatively, or in addition, a freeness of the fibre suspension deposited in the first period 102 may be different than a freeness of the fibre suspension deposited in the second period 106. Without wishing to be bound by the theory, it is thought that that the freeness of a fibre suspension may impact how evenly fibres are distributed within the cavity 36. Suitable selection of the freeness for the fibre suspensions deposited in the first and second periods 102, 106 may therefore assist in providing a fibre layer with appropriate characteristics. As an example, a higher freeness may allow the fibre suspension deposited in the first period 102 to achieve a relatively even initial distribution of fibres within the cavity.
While in the particular example illustrated in
More generally, it should be noted that it is by no means essential that the system 100 uses a valve to restrict/prevent deposition of fibre suspension within the cavity 36 of the mould 15. In other examples, a flow diverter could divert a variable amount of fibre suspension for recirculation, with the remainder of the fibre suspension being deposited within the cavity 36 of the mould.
Attention is now directed to
It will be noted that, in the particular example shown, the second layer 44b covers the majority of, or the entirety of, the first layer 44a. However, this is by no means essential and in other examples, the second layer 44b might cover or overlap the first layer 44a only partially, or may not overlap the first layer 44a at all. Similarly, while in the particular example shown the first layer 44a covers the majority of, or the entirety of the internal surfaces 40 that define the cavity 36, this is by no means essential and in other examples, the first layer 44a might cover the internal surfaces 40 only partially, or not at all. Moreover, in examples where fibre suspension is selectively deposited so that the first layer 44a only partially covers the internal surfaces 40 of the cavity 36, the negative pressure that is generated within the cavity during the pressure build-up period 104 may tend to encourage the second layer 44b to be preferentially formed over part(s) of the internal surfaces 40 that are not covered by the first layer 44a.
Returning now to
It should also be noted that, while in the particular example shown in
Again referring to
On the other hand (and regardless of whether the system operates in a start-up period 101), it should be understood that it is not essential that the negative pressure source 70 applies negative pressure to the exterior of the mould 15 during the first deposition period 102. In particular, it should be understood that the application of negative pressure to the exterior of the mould 15 is not essential to the introduction of fibre suspension into the mould 15. Various approaches for introducing fibre suspension into the mould 15 may be employed that do not rely on suctioning the fibre suspension against the internal surfaces 40 of the mould 15 using the negative pressure source 70. Nevertheless, given that the negative pressure source 70 applies negative pressure to the exterior of the mould 15 during the second deposition period 106, operation of the system 100 may be simplified where the system functions in generally the same way during the first deposition period 102.
In some examples, the control system 80 may be configured to control the system 100 so as to operate in a venting period 107, which is after the second deposition period 106. During this venting period 107, the cavity 36 of the mould 15 is vented, for example by opening the cavity 36 to the atmosphere via an opening or passage. As illustrated in
Where the cavity 36 is opened to the atmosphere during the venting period 107, the pressure within the cavity 36 may be allowed to continue to rise until it equalizes with atmospheric pressure. This may facilitate the disconnection of the fibre suspension supply system 50 from the mould 15, particularly in embodiments where the connecting portion 60 of the fibre suspension supply system 50 is configured to form a fluid-tight seal with the mould 15 when engaged therewith (such as, for example, embodiments where the connecting portion 60 comprises a bung). Disconnection of the fibre suspension supply system 50 from the mould 15 may, for example, allow a further system to engage with the mould, such as a system for removing further suspending liquid (e.g. water) from the receptacle 22, and/or for consolidating the three-dimensional shape of the receptacle. Such a system might, for example, comprise an impermeable inflation element 19, e.g., a collapsible bladder, as shown in
Particularly (but not exclusively) where the fibre suspension supply system 50 is disconnected from the mould 15 during or after the venting period 107, the control system 80 may prevent (or perhaps limit to a very low level) the deposition of fibre suspension within the cavity 36 of the mould 15 during the venting period 107. In the embodiment illustrated in
Reference is now directed to
The fibre suspension supply system 50′ shown in
In a particular example, tanks 56a and 56b may contain respective, different fibre suspensions, whereas tank 56c may contain water. More particularly, the fibre suspensions in tanks 56a and 56b may, for instance, have respective, different average fibre lengths. Thus, by mixing the two fibre suspensions in specific proportions (e.g. determined based on control signals/data received from the control system 80), a fibre suspension having a desired average fibre length can be achieved. Furthermore, by adding a specific amount of water from tank 56c (e.g. determined based on control signals/data received from the control system 80), a desired freeness for the fibre suspension can be achieved. It will, however, be appreciated that this is merely one example of an approach that allows the composition of a fibre suspension to be controlled. In other examples, more or fewer tanks could be provided and other compositions could be provided within each such tank.
Reference is now directed to
As shown at block 202, the method comprises, during a first deposition period, depositing a first volume of a first fibre suspension within a cavity 36 of a mould 15. As illustrated in
At block 204, the method 200 comprises, during a pressure build-up period 104, which is after the first deposition period 102, applying negative pressure to the exterior of the mould 15, while restricting deposition within the cavity 36 of the first fibre suspension and a second fibre suspension (which is deposited during a second deposition period, discussed below). As a result of the application of negative pressure to the exterior of the mould 15, in combination with the restriction of deposition of the first and second fibre suspensions within the cavity 36, a negative pressure of increasing magnitude is generated within the cavity 36.
At block 206, the method 200 comprises, during a second deposition period 106, which is after the pressure build-up period 104, depositing a second volume of a second fibre suspension within the cavity 36 of the mould 15, while applying negative pressure to the exterior of the mould.
Because a negative pressure of increasing magnitude is generated within the cavity 36 during the pressure build-up period 104, when the second volume of second fibre suspension is then deposited, the second fibre suspension may preferentially accumulate at locations within the cavity where less of (or none of) the first fibre suspension is present. Consequently, a deposited fibre layer that better covers the internal surfaces defining the cavity and/or has a relatively uniform thickness may be provided by the thus-deposited second volume of the second fibre suspension in combination with the first volume of the first fibre suspension.
It should be noted that the first and second fibre suspensions need not be different; in some examples, they may be the same. Furthermore, the first and second volumes need not be different and may, in some examples, be the same.
As mentioned above, the method 200 may, for example, be implemented using a receptacle moulding system 100 according to one of the examples described above with reference to
Reference is now directed to
The receptacle 22 is obtainable or obtained from a fabrication method that comprises any of the above-described methods for manufacturing a moulded receptacle, such as the method 200 described above with reference to
The fabrication method may, in some examples, comprise at least one process in addition to the above-described methods for manufacturing a moulded receptacle. For example, the at least one additional process may comprise further moulding a receptacle as produced by one of the above-described methods for manufacturing a moulded receptacle (such as method 200 illustrated in
As another example, the at least one additional process may comprise coating and drying a receptacle as produced by one of the above-described methods for manufacturing a moulded receptacle (or a further-moulded receptacle produced by further moulding such a moulded receptacle) to produce a coated receptacle. As described above with reference to
In a still further example, the at least one additional process may comprise applying a closure to such a receptacle, further-moulded receptacle or coated receptacle. For example, a neck fitment 35 may be affixed, as is the case with the receptacle shown in
Example embodiments of the present invention have been discussed, with reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made without departing from the scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2209797.6 | Jul 2022 | GB | national |
This application is a continuation under 35 U.S.C. § 120 of International Application No. PCT/GB2023/051691, filed Jun. 29, 2023, which claims priority to United Kingdom Application No. GB 2209797.6, filed Jul. 4, 2022, under 35 U.S.C. § 119 (a). Each of the above-referenced patent applications is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/GB2023/051691 | Jun 2023 | WO |
| Child | 19004102 | US |