GB2479882A

GB2479882A - Manufacturing pulp moulded articles

Info

Publication number: GB2479882A
Application number: GB1006987A
Authority: GB
Inventors: Ryan Kelly
Original assignee: ROBERT CULLEN Ltd
Current assignee: ROBERT CULLEN Ltd
Priority date: 2010-04-27
Filing date: 2010-04-27
Publication date: 2011-11-02
Also published as: GB201006987D0

Abstract

A method and apparatus for manufacturing pulp moulded articles, such as urine bottles 16' comprises a vacuum mould 10' with first and second separable mould portions 12', 14' each provided with fluid permeable inner surfaces. Pulp slurry stock is introduced into the vacuum mould 10', which is held closed while a pressure differential is applied across its fluid permeable inner surfaces to deposit the pulp thereon and produce a wet formed article. The first and second mould portions 12', 14' are separated while maintaining a pressure differential across the fluid permeable inner surface 12a' of one of the mould portions 12' to hold the wet formed moulded article thereon once the other mould portion 14' no longer provides support. The pressure differential may then be removed or reversed to release the wet formed moulded article 16' from its mould portion onto a conveyor 26' which conveys the article into a drying oven. The mould portions 12',14' may be arranged on platens 18' connected to an actuation arm 30', and the platens are guided, preferably by pins (40, Figure 5) guided in slots (42), such that they separate from each other as the actuation arm 30' is rotated.

Description

Apparatus and Method for Manufacturing Pulp Moulded Articles The present invention relates to an apparatus and method for manufacturing pulp moulded articles and particularly, but not exclusively, to a high throughput apparatus and method for vacuum manufacturing of hollow pulp moulded containers.

Hollow pulp moulded articles such as disposable containers are well known. Pulp moulded containers are particularly suitable for single-use applications within the medical care sector and help to avoid cross infection between patients. Other advantages of such containers include ease of disposal by maceration, low environmental impact through use of recycled materials, and associated relatively low unit cost for manufacture.

Containers of this type may include, for example, disposable urine bottles and the like.

It should be noted that the word "hollow" appearing throughout the present application is used to define articles which are enclosed by walls extending more than 180 degrees around an axis; that is to say, the article requires at least a two-part rriould for its manufacture.

Automated and semi-automated rotary production processes by which such hollow articles can be manufactured are well established and typically involve the steps of: (i) providing a pulp slurry stock comprising a mixture of water and raw fibrous materials such as recycled paper; (ii) introducing the pulp slurry stock into multi-part forming dies under pressure and/or vacuum conditions to produce wet formed articles; (iii) releasing the wet formed articles from the forming dies and transferring them onto an oppositely moving retaining pin; (iv) conveying the retained wet formed articles through a drying oven; and (v) packing of the dried hollow articles ready for shipment.

However, aspects of apparatus used in processes of the aforementioned type suffer from a number of disadvantages. For example, the machinery used to produce hollow pulp articles suffers from high capital costs in view of its complexity, energy inefficiency, and large factory footprint and manpower requirements.

Particular problems are associated with the use of the aforementioned mechanical retaining pins used to transfer the wet formed articles from the forming dies into the drying oven. For example, the act of transferring a wet formed article onto the retaining pin requires precise stepwise coordination and alignment between the oppositely rotating forming dies and the retaining pins respectively. This requirement can limit the throughput of the apparatus. Mechanical retaining pins also represent an additional component of the overall apparatus which must be maintained, cleaned and, over time, replaced thus contributing to additional capital and operational costs of the apparatus. Moreover, the high water content of wet formed articles prior to the drying stage mean that they are pliable and hence highly susceptible to impact damage caused by contact with retaining pins.

It would therefore be desirable to provide an apparatus and method for manufacturing pulp moulded articles which mitigates or obviates the aforementioned disadvantages whilst providing significant productivity, quality and efficiency benefits.

According to a first aspect of the present invention there is provided apparatus for manufacturing pulp moulded articles, the apparatus comprising a vacuum moulding member having first and second separable mould portions each provided with fluid permeable inner surfaces; the first and/or second mould portion(s) being movable in a cyclical manner between (i) a fully closed position in which the fluid permeable inner surfaces of the vacuum moulding member define the contours of an article to be vacuum moulded; and (ii) a fully open position wherein the respective mould portions are sufficiently separated to release a moulded article formed within the vacuum moulding member; and wherein one of the mould portions is adapted to retain a moulded article thereon solely by application of a pressure differential across its fluid permeable inner surface when the vacuum moulding member is in its open position.

Optionally, the mould portion adapted to retain the moulded article is positioned above the other mould portion when the vacuum moulding member is in its open position.

Optionally, the apparatus comprises first and second platens upon which the respective first and second mould portions of the vacuum moulding member are mounted.

Optionally, the first and second platens are hingedly connected to facilitate their movement between the open and closed positions.

Optionally, the hinged connection between the first and second platens is positioned outside the perimeter of each mould portion of the vacuum moulding member to facilitate complete separation of the mould portions when in their open position.

Optionally, the apparatus comprises an actuation arm, and the first and second platens are connected thereto by the hinged connection.

Optionally, the first and second platens include guide means to guide their movement between the open and closed positions.

Optionally, the guide means comprise at least one guide pin arranged for relative movement along a guide rail.

Optionally, the actuation arm is pivotable in response to an actuation means between a fully retracted position in which the respective platens are converged into the vacuum moulding member's closed position and retracted against the arm; and a fully extended position in which the respective platens are diverged apart into the vacuum moulding member's open position.

Optionally, the actuation arm is connected to an endless track which moves in a cyclical manner.

Optionally, the apparatus comprises a plurality of actuation arms connected to the endless track.

Optionally, each vacuum moulding member comprises a plurality of first and second mould portion pairs.

Optionally, the mould portion which is uppermost when the vacuum moulding member is in its open position is presented in a substantially horizontal orientation when the vacuum moulding member is in the fully open position.

Optionally, the first and second mould portions define an aperture when the vacuum moulding member is in the fully closed position.

Optionally, the fluid permeable inner surfaces of the vacuum moulding member define the contours of a hollow article.

Optionally, the fluid permeable inner surfaces of the vacuum moulding member define the contours of a disposable urine bottle.

According to a second aspect of the present invention, there is provided a method of manufacturing pulp moulded articles, the method comprising the steps of: (i) providing a vacuum moulding member having first and second separable mould portions each provided with fluid permeable inner surfaces; (ii) providing a pulp slurry stock comprising a mixture of water and fibrous materials; (iii) introducing the pulp slurry stock into the vacuum moulding member when it is in a closed position; (iv) maintaining the vacuum moulding member in its closed position whilst applying a pressure differential across its fluid permeable inner surfaces to deposit the pulp thereon and produce a wet formed article corresponding in shape with the desired end product; (v) separating the first and second mould portions whilst maintaining a pressure differential across the fluid permeable inner surface of one of the mould portions to thus retain the wet formed moulded article thereon once the other mould portion no longer provides support; and (vi) removing or reversing the pressure differential to release the wet formed moulded article from its mould portion.

Optionally, the method comprises the further step of releasing the wet formed moulded article onto a conveyor which conveys the article into a drying oven.

Optionally, the vacuum moulding member operates in a continuous cycle such that once the wet formed moulded article is released, the vacuum moulding member is returned to its closed position before repeating steps (iii) to (vi) above.

Optionally, the mould portions are arranged on platens connected to an actuation arm, and the platens are guided such that the platens separate from each other as the control arm is rotated.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic representation of a prior art apparatus for manufacturing pulp moulded articles showing the vacuum moulding member in a closed position, and in alignment with a retaining pin mounted on a conveyor; Fig. 2 is a schematic representation of the prior art apparatus of Fig. 1 showing the vacuum moulding member in an open position whereby the nioulded article has been transferred onto the moving retaining pin; Fig. 3 is a schematic representation of the pulp moulding apparatus of the present invention showing the vacuum moulding member in a closed position; Fig. 4 is a schematic representation of the pulp moulding apparatus of Fig. 3 showing the vacuum moulding member in an open position whereby the nioulded article is retained on its uppermost mould portion; and Figs. 5 and 6 are schematic representations of the pulp moulding apparatus of Fig. 3 showing the platens in the closed and open positions respectively.

Figs. 1 and 2 show a prior art arrangement in which the apparatus comprises a vacuum moulding member 10 having first and second separable mould portions 12, 14 each of which are provided with fluid permeable inner surfaces 1 2a, 1 4a made from metal gauze or the like.

The first and second mould portions 12, 14 are movable in a sequential manner between: (i) a fully closed position -shown in Fig. 1 -in which the inner surfaces 1 2a, 1 4a are brought together to define the contours of an article to be vacuum moulded; and (ii) a fully open position -shown in Fig. 2 -in which the inner surfaces 12a, 14a are pivoted apart to release a moulded article formed therein. In the illustrated example, the article is a hollow disposable urine bottle 16 having an opening or neck 1 6a which is relatively narrow compared with its body.

The vacuum moulding member 10 is mounted to a platen 18 provided with hydraulically operated rams 20 which provide operating forces to open and close the mould portions 12, 14 about a hinge 22. A vacuum is applied to the rear faces of the closed mould portions thereby drawing pulp through an aperture defined between the mould portions 12, 14 corresponding to the opening or neck 1 6a of the urine bottle 16. The pulp is drawn against the inner surfaces 1 2a, 1 4a to thus produce a wet formed article of the desired shape. During this process, the vacuum moulding member 10 is moved on an endless track in a clockwise to the position shown in Fig. 1.

When in this position, the opening or neck 16a is aligned with the longitudinal axis of a retaining pin 24 mounted on an endless clockwise conveyor 26.

Once this alignment is achieved, the platen 18 is moved towards the retaining pin 24 whilst simultaneously opening mould portions 12, 14 about their hinge 22. In doing so, the urine bottle 16 is released such it is retained by means of the retaining pin 24 inserted into its opening or neck 16a. The platen 18 then retracts away from the retaining pin 24 which is then conveyed in a step-wise manner to transfer the urine bottle 16 carried thereon through a drying oven (not shown) in the usual manner whereby its moisture content is reduced to the desired level. The above apparatus and method is already well established in the field of pulp moulding and so will not be described in any further detail.

Figs. 3 and 4 show the apparatus of the present invention in which the apparatus comprises a vacuum moulding member 10' having first and second separable mould portions 12', 14' and fluid permeable inner surfaces 12a', 14a' which operate in a similar manner to that already described above with reference to Figs. 1 and 2. The article illustrated in Figs. 3 and 4 is also a hollow disposable urine bottle 16' having an opening or neck 16a' which is relatively narrow compared with its body.

However, the apparatus of Figs. 3 and 4 differs from the prior art apparatus in a number of respects as described in more detail below.

The mould portions 12', 14' of the vacuum moulding member 10' are mounted to a pair of platens 18' which open and close the mould portions 12', 14' about a hinge 22'. Importantly, the hinge 22' is positioned outside the perimeter of each mould portion 12', 14' at the side lying opposite to the opening or neck 16a' of the urine bottle 16'. This arrangement facilitates complete separation of the mould portions 12', 14' when in the fully open position shown in Fig. 4 and provides advantages which are discussed in further detail below.

The platens 18' are each connected to an actuation arm 30' about the hinge 22'. The actuation arm 30' is therefore pivotable in response to an actuation means (not shown) between a fully retracted position -shown in Fig. 3-in which the respective platens 18' are converged into the vacuum moulding member's 10' closed position and retracted against the arm 30'; and a fully extended position in which the respective platens 18' are diverged apart into the vacuum moulding member's 10' open position.

The actuation arm 30' -which may be one of a plurality of such arms -is connected to an endless track (not shown) which moves in a clockwise cyclical manner. Similarly, each vacuum moulding member 10' may comprise a plurality of first and second mould portion pairs 12', 14' to thus increase the throughput of the apparatus in terms of the number of the urine bottles 16' manufactured per unit time.

Whilst it is known to scale up the manufacturing process in this way, a further feature of the present invention contributes to a significant improvement in productivity, quality and efficiency. Such improvements are achievable by adapting the prior art apparatus such that the retaining pins 24 illustrated in Figs. 1 and 2 are no longer required. This is facilitated by applying a pressure differential across the inner surface I 2a' of the uppermost mould portion 12' as the mould portions 12', 14' are separated towards the fully open position shown in Fig. 4. The pressure differential acts to retain the upper surface of the wet formed urine bottle 16' against the inner surface 1 2a' even once the lower surface of the urine bottle 16' is unsupported in view of the absence of the other mould portion 14'. Typically a vacuum pressure of up to 4 bar may be applied to hold the formed article 16' against the upper mould 12'.

As is shown in Fig. 4, the uppermost platen 18', its associated mould portion 12', and the urine bottle 16' retained therein are each presented in a substantially horizontal orientation when the actuation arm 30' is in its fully extended position. In this position, the urine bottle 16' is suspended above an endless conveyor moving in a clockwise direction. The urine bottle 16' is then deposited onto the moving conveyor 26' by removing the pressure differential across the inner surface I 2a' of the uppermost mould portion 12'. To assist in separation of the urine bottle 16' from the uppermost mould portion 12' a short blast of air may be provided, to blow the moulded article onto the conveyor 26'. The conveyor 26' is formed from stainless steel to avoid transferring rust marks to the urine bottles 16'.

The actuating arm 30' and platens 18' then retract away from the conveyor 26' which is then conveyed in a clockwise direction to transport the urine bottle 16' through a drying oven (not shown) in the usual manner whereby its moisture content is reduced to the desired level. The actuating arm 30' and platens 18' are then cleaned with water jets before reverting to their retracted and closed positions after which the above process is repeated.

Figs. 5 and 6 show how movement of the actuating arm 30' causes the platens 18' to converge and retract. Each platen 18' is provided with a guiding pin 40 which engages with a guiding rail 42 provided in an upper guide 44a or lower guide 44b. When the arm 30' rotates clockwise, to the position shown in Fig. 5, the pins 40 are restrained in the rails 42 SO that the platens 18' converge to a closed position, in which the mould portions 12', 14' are held closed for forming the urine bottle 16'. When the arm 30' rotates counter-clockwise, to the position shown in Fig. 6, the pins 40 are restrained in the divergent rails 42 so that the platens 18' separate and open, allowing the removal of the moulded product 16' from the separated mould portions 12', 14'.

It will be appreciated that by obviating the need for retaining pins on the conveyor, the apparatus for manufacturing pulp moulded articles is greatly simplified, the associated manufacturing method is made more efficient, and the end product is of a higher quality. For example, the apparatus of the present invention has less component parts meaning that maintenance costs can be reduced. The manufacturing method can be made to progress more quickly and efficiently since there is no longer any need for a stepwise movement of the conveyor 26', or for maintaining careful alignment and coordination between the conveyor 26' and each vacuum moulding member 10'. The apparatus and method of the present invention also ensures that the wet formed urine bottles 16' are of a consistently high quality by being free of any impact damage caused by their small surface area of contact with the retaining pins 24 prior to the drying stage. The upper surfaces of the wet formed urine bottles 16' have a high surface area of contact with the uppermost mould portion 12' prior to being deposited onto the conveyor 26'. Similarly, the lower surfaces of the wet fornied urine bottles 16' have a high surface area of contact with the conveyor 26' once they are deposited. Urine bottles 16' produced by the apparatus and method of the present invention fully conform to the PAS 29:2009 standard: "Disposable pulp products for use in healthcare".

The apparatus and method of the present invention allows throughput to be increased without any increase in energy or manpower costs and hence provides a higher return on capital investment and optimises the factory footprint space being utilised. As an example, known urine bottle manufacturing machines employing the traditional retaining pins can produce approximately 1500 units per hour. Meanwhile, the apparatus and method of the present invention yields approximately 3500 units per hour. The use of guiding pins 40 on the platens 18' to guide the platens 18' while they open results in the platens 18' moving in a diving motion towards the conveyor, causing the mould portions 12', 14' to separate and the moulded article 16' to be deposited directly onto a conveyor belt by the upper platen. Because the conveyor 26' does not require retaining pins 24, the moulded articles 16' can be placed directly onto the conveyor belt 26', so there is no need to slow the platens 18' down to a speed at which they can safely and accurately place the moulded article 16' onto a retaining pin 24.

Modifications and improvements may be made to the foregoing without departing from the scope of the present invention as defined by the accompanying claims. For example, the apparatus is operated by Pro Logic Control (PLC) to allow programmable adjustments to be applied to the manufacturing process in real time. The apparatus is driven by a high speed SERVO control system to allow remote control and communication of the machine motors. A heat recovery system is used to recycle the processed water from the vacuum pumps through heat exchangers in the drying oven to provide controlled temperatures for the water used in the pulp slurry. This combined with the employment of energy efficient inverters, the use of reinforced steel to stabilise the apparatus against undesired operational movement, and upgraded gearboxes and vacuum pumps will optimise the speed and energy efficiency of the apparatus and reduce its overall carbon footprint.

Claims

CLAIMS1. Apparatus for manufacturing pulp moulded articles, the apparatus comprising a vacuum moulding member having first and second separable mould portions each provided with fluid permeable inner surfaces; the first and/or second mould portion(s) being movable in a cyclical manner between (i) a fully closed position in which the fluid permeable inner surfaces of the vacuum moulding member define the contours of an article to be vacuum moulded; and (ii) a fully open position wherein the respective mould portions are sufficiently separated to release a moulded article formed within the vacuum moulding member; and wherein one of the mould portions is adapted to retain a moulded article thereon solely by application of a pressure differential across its fluid permeable inner surface when the vacuum moulding member is in its open position.
2. Apparatus according to claim 1, wherein the mould portion adapted to retain the moulded article is positioned above the other mould portion when the vacuum moulding member is in its open position.
3. Apparatus according to claim 1 or 2, wherein the apparatus comprises first and second platens upon which the respective first and second mould portions of the vacuum moulding member are mounted.
4. Apparatus according to claim 3, wherein the first and second platens are hingedly connected to facilitate their movement between the open and closed positions.
5. Apparatus according to claim 4, wherein the hinged connection between the first and second platens is positioned outside the perimeter of each mould portion of the vacuum moulding member to facilitate complete separation of the mould portions when in their open position.
6. Apparatus according to any of claims 3 to 5, wherein the apparatus comprises an actuation arm, and the first and second platens are connected thereto by the hinged connection.
7. Apparatus according to claim 6, wherein the first and second platens include guide means to guide their movement between the open and closed positions.
8. Apparatus according to claim 7, wherein the guide means comprise at least one guide pin arranged for relative movement along a guide rail.
9. Apparatus according to any of claims 6 to 8, wherein the actuation arm is pivotable in response to an actuation means between a fully retracted position in which the respective platens are converged into the vacuum moulding member's closed position and retracted against the arm; and a fully extended position in which the respective platens are diverged apart into the vacuum moulding member's open position.
10. Apparatus according to any of claims 6 to 9, wherein the actuation arm is connected to an endless track which moves in a cyclical manner.
11. Apparatus according to claim 10, wherein the apparatus comprises a plurality of actuation arms connected to the endless track.
12. Apparatus according to any preceding claim, wherein each vacuum moulding member comprises a plurality of first and second mould portion pairs.
13. Apparatus according to any preceding claim, wherein the mould portion which is uppermost when the vacuum moulding member is in its open position is presented in a substantially horizontal orientation when the vacuum moulding member is in the fully open position.
14. Apparatus according to any preceding claim, wherein the first and second mould portions define an aperture when the vacuum moulding member is in the fully closed position.
15. Apparatus according to any preceding claim, wherein the fluid permeable inner surfaces of the vacuum moulding member define the contours of a hollow article.
16. Apparatus according to any preceding claim, wherein the fluid permeable inner surfaces of the vacuum moulding member define the contours of a disposable urine bottle.
17. A method of manufacturing pulp moulded articles, the method comprising the steps of: (i) providing a vacuum moulding member having first and second separable mould portions each provided with fluid permeable inner surfaces; (ii) providing a pulp slurry stock comprising a mixture of water and fibrous materials; (iii) introducing the pulp slurry stock into the vacuum moulding member when it is in a closed position; (iv) maintaining the vacuum moulding member in its closed position whilst applying a pressure differential across its fluid permeable inner surfaces to deposit the pulp thereon and produce a wet formed article corresponding in shape with the desired end product; (v) separating the first and second mould portions whilst maintaining a pressure differential across the fluid permeable inner surface of one of the mould portions to thus retain the wet formed moulded article thereon once the other mould portion no longer provides support; and (vi) removing or reversing the pressure differential to release the wet formed moulded article from its mould portion.
18. A method according to claim 17, comprising the further step of releasing the wet formed moulded article onto a conveyor which conveys the article into a drying oven.
19. A method according to claim 18, wherein the vacuum moulding member operates in a continuous cycle such that once the wet formed nioulded article is released, the vacuum moulding member is returned to its closed position before repeating steps (iii) to (vi) above.
20. A method according to any one of claims 16 to 19, wherein the mould portions are arranged on platens connected to an actuation arm, and wherein the platens are guided such that the platens separate from each other as the control arm is rotated.