It is estimated that around 19 million tonnes of waste paper is generated by EU businesses per annum. Although the percentage of waste paper being recycled continues to increase across the EU, the cost of recycling often means that the waste paper generated by small businesses and offices, as well as larger industrial bodies and corporations, is not recycled through paper merchants. In general, this is because most small business and offices do not produce a high enough volume of waste paper to warrant free collection by paper merchants. Therefore, a significant amount of waste paper ends up in landfills and the like, at a cost to both small businesses and the environment.

It is an object of the invention to provide an apparatus that addresses the above issues.

According to a first aspect of the invention, there is provided an apparatus for use in recycling paper material, the apparatus comprising a housing unit including an inlet for receiving paper material to be recycled and a first processing chamber having means adapted for producing a pulp from paper material, a second processing chamber having a screw device rotatably mounted therein, the screw device being arranged for receiving the pulped material from the first processing chamber and having a pitch configured for driving the pulped material along its length for refining the pulped material, the screw device being further arranged for squeezing liquid from the pulped material, the second processing chamber including means for recovering the liquid squeezed from the pulped material, the unit including a third processing chamber for adding binder to the pulped material after it has passed through the second processing chamber, and means arranged for producing a paper web from the pulped material after it has been processed by the third processing chamber.

Conveniently, the means for recovering liquid from the second processing chamber includes means for collecting the liquid and means for recycling the liquid for use in the first processing chamber.

The preferred unit is therefore advantageous in that it is configured to recycle its own processing liquid, without the need for a constant mains supply of water for producing pulped material, for example.

Preferably, the means for recovering liquid from the second processing chamber includes a plurality of slots arranged in a wall of the second processing chamber, the slots being arranged for allowing liquid to drain out of the chamber in an opposite direction to the effective direction of travel of the pulp material on the screw device.

The apparatus in accordance with the invention is preferably of a small-scale construction, for example a unit of a similar size to a domestic food refrigerator, and may be configured for producing absorbent wipes or the like.

Not only are small businesses and offices spending money to dispose of waste paper in landfills, they also spend money on paper towels and the like for the cleaning work surfaces, as well as bathrooms and kitchens, for example. Thus, the invention is of particular advantage in that the waste paper generated by small businesses can be converted to paper towel type wipes or the like, thus saving money which might otherwise be spent on both waste paper disposal and paper towels and the like.

In alternative embodiments, the invention may also be used for creating packaging or compacted paper for burning.

According to a further aspect of the invention, there is provided an apparatus for use in making paper type material, the apparatus comprising a screw barrel arrangement for receiving pulped material paper making material, the screw barrel arrangement including a chamber having an inlet, a screw device rotatably mounted in chamber, the screw device being arranged for receiving the pulped material from the inlet and having a pitch

configured for driving the pulped material along its length for refining the pulped material, the screw device being further arranged in the chamber for squeezing liquid from the pulped material, the screw chamber also having means for recovering the liquid squeezed from the pulped material.

Other aspects and preferred features of the invention will be apparent from the foregoing description and the dependent claims.

Figure 1 is a diagram showing a recycling unit according to a preferred embodiment of the invention ; Figure 2 is a schematic, part cross sectional diagram showing the internal components of the unit of Figure 1; Figure 3 is an enlarged schematic view of the screw barrel arrangement from Figure 2 ; and Figure 4 is a schematic, part cross sectional view of part of a recycling apparatus in accordance with another preferred embodiment of the invention.

Figure 1 shows a recycling apparatus in the form of a micro-scale stand-alone recycling unit in accordance with a preferred embodiment of the invention, indicated at 10. In this embodiment, the unit 10 is adapted for converting waste paper to general-purpose absorbent paper wipes. The unit 10 is in the form of a portable housing of a similar size to a medium size domestic food refrigerator or office filing cabinet. For example, the embodiment shown in Figure 1 has a height of approximately 1.5 m, a width of approximately 0. 85 m and a depth of approximately 0.85 m. The unit 10 is particularly suited for use in an office or other business environment, or in a laboratory, in which the wipes generated by the unit 10 can then be used for general cleaning purposes. However, the size of the unit can be customised, as required, for example to the size of a typical food vending machine.

Internal components of the unit 10 are shown in Figure 2. The unit 10 includes an inlet in the form of a tray 12, for receiving waste paper to be recycled (indicated at 11). A motor driven paper feed arrangement 14 is provided at one end of the tray 12, to the right as shown in Figure 2. A paper shredder 16 is arranged beneath the tray 12 for receiving and shredding paper passing from the paper feed arrangement 14.

A first processing chamber 18 having an outlet 19 is arranged adjacent the output end of shredder 16, to receive shredded waste paper for bleaching and de-inking, and for creating a pulp from the shredded paper. The chamber 18 includes a motor driven processor 20 having blades 21. The blades 21 are arranged beneath the shredder 16 and are intended to be motor driven for blending the shredded paper as it drops onto the blades, in the manner of a food processor, for processing into a finer particulate material.

An ozone input means 22 is also provided in communication with the chamber 18, for selectively introducing ozone or ozonated water (i. e. water in which ozone has been diffused) into the chamber 18, as will be described in more detail below. A water tank 24 is arranged above the chamber 18 for supplying water to the chamber 18 for the recycling process, and a solenoid control valve 25 is provided to regulate the flow of water from the tank 24 to the chamber 18, through electronic actuation. The processor 20 also acts as a viscometer for monitoring the consistency of the pulped material. The processor 20 includes sensors for monitoring the resistance to the rotation of the blades 21, for monitoring the viscosity of the liquid/paper mixture in the chamber 18. The chamber 18 includes sensors (not shown) for monitoring parameters within the first processing chamber 18, such as the ozone level and the pH value of paper/liquid mixture present in the chamber 18.

A compact twin barrel extrusion arrangement, indicated at 26, is provided in communication with the outlet 19 of the first processing chamber 18, via a solenoid control valve 27. The extrusion arrangement 26 is arranged for receiving pulp from the chamber 18, and includes first and second co-axial extrusion barrels or chambers 28,30, shown most clearly in Figure 3. As can be seen clearly in Figures 2 and 3, the first and second barrels 28, 30 are connected via a conduit 28A. The conduit 28A is of a smaller

diameter than the barrels 28 and 30, and effectively forms a constriction at the left hand end of the first barrel 28.

A motor driven screw, shown diagrammatically at 29, of varying pitch extends through first and second barrels 28, 30 and the conduit 28A. The pitch of the screw 29 is configured for urging pulp in the direction of the axis of the screw 29, from right to left as shown in Figures 2 and 3, and for compressing and refining the pulp during rotation of the screw, as will be described in more detail below. It will be appreciated that the diameter of the portion of the screw 29 extending through the conduit 28A is smaller than the diameter of the rest of the screw 29.

The walls of the conduit 28A and the left hand end wall of the first barrel 28 provide a reaction surface in the screw barrel arrangement 26, against which pulp material is driven in use, as will be described in more detail below.

The base wall 33 of the first barrel 28 includes slots, shown clearly in Figure 3 at 31, for passage of water from the pulp. The slots 31 extend across the base wall, orthogonal to the longitudinal axis of the barrel 28. The slots 31 are also configured so as to be rearwardly inclined at an angle to the longitudinal axis of the screw 29, which in this embodiment is an angle of 45 degrees. The slots 31 are formed in this manner so as to extend in the opposite direction to the pitch of the screw 29, as can be seen from Figure 3, so that when pulp is driven by the screw 29, from right to left as viewed in Figures 2 and 3, the passage of pulp material down through the slots 31 is limited.

A collecting tray 32 is provided beneath the first barrel 28, for collecting water or matter passing through the slots 31 in the first barrel 28. The collecting tray 32 is in fluid communication with a condenser tank 34, via a solenoid control valve 33. The condenser tank 34 includes a sub-tank 35 arranged for receiving processing water from the collecting tray 32. A heater 36 is mounted in the sub-tank 35, for evaporating processing water and thus separating ink and other solids from the processing water. The evaporated water is then recovered, so as to be recycled for use in the unit 10, as discussed in more detail below.

The unit 10 also includes a free piston sterling engine, having a condenser portion 37 and a heater portion 38. However, it should be noted that any suitable form of heater or condenser may be utilised in preferred embodiments of the invention. The condenser portion 37 is located in the condenser tank 34, and is used for condensing evaporated water from the sub-tank 35. The heater portion 38 is used as a dryer for drying recycled paper web produced by the unit 10, as described in more detail below.

The condenser tank 34 has an outlet conduit 40, which is arranged for supplying condensed water to a sediment tank 42. A return conduit 44 extends from the sediment tank 42 to the water tank 24. A motor driven pump 46 is provided in the conduit 44 for circulating water from the recycling process, under pressure, back to the water tank 24.

An optical or refractive sensor 48 is also included in the return conduit 44 for monitoring the solid content of the circulating water from the sediment tank 42.

A vessel 50 for paper binder chemicals is arranged for introducing binder chemicals into the second barrel 30. The second barrel 30 is connected to an outlet conduit 52 for supplying pulp from the extrusion arrangement 26, under pressure, to a press apparatus 54 for forming a paper web from the pulp. The press apparatus 54 includes a series of press rollers, indicated at 56, arranged for the passage of pulp from the extrusion arrangement 26, to form a continuous web of recycled paper. The press apparatus 54 also includes a dryer 38, which (as referred to above) is part of the free piston sterling engine 35 mounted in the condenser tank 34. Beneath the portion of the press apparatus adjacent the dryer, there is provided a series of polished, close-stacked metal rollers known as a"calender", indicated at 58, which is adapted for pressing smooth the dried web.

The press apparatus 54 terminates at an outlet dispenser portion 60 of the unit 10, which includes a cutter 62 in the form of a serrated blade, for cutting a length from the recycled web, indicated at 64, as required.

A typical operation of the unit 10 in producing a recycled paper wipe will now be described.

Waste paper 11 is inserted into the tray 12 and is fed by the paper feed arrangement 14 into the shredder 16. The waste paper 11 is shredded and strips of the shredded paper falls into the chamber 18. Water from the water tank 24 is introduced into the chamber 18, and the blades 21 of the processor/viscometer 20 are used to agitate and blend the water/paper mixture, i. e. cut through the strips of shredded paper, in the manner of a food processor, for processing the strips into a finer particulate material, to create a pulp from the mixture. Ozone or ozonated water is introduced into the mixture through the ozone input means 22. The ozone acts as an aggressive agent for de-inking and bleaching the shredded waste paper, as well as sterilizing the pulp by killing organisms in the pulp.

The viscometer 20 measures the viscosity of the paper liquid mixture and the resulting pulp and a computerised control unit (not shown) monitors the viscometer output, for controlling the flow characteristics of the mixture/pulp, as required. If more water is required, i. e. to increase the flow of the mixture/pulp, the control unit acts to open valve 25 to allow a volume of water to pass into the chamber 18. The control unit monitors the data from the sensors in the chamber 18, for example to monitor the ink concentration within the mixture, or for controlling the amount of ozone being introduced to sufficiently reduce the shredded paper into a bleached pulp. The ozone has the ability to substantially breakdown ink and dirt such as oil or grease. The monitoring of the water content is important for reducing wastewater and in achieving a pulp having a desired, optimal flow characteristic and consistency, with minimum energy consumption. The monitoring of the pulp in this way can also be calibrated and used for regulating the quality of the recycled web to be produced by the unit 10, for example, for producing a wipe of optimal softness and absorbency.

Once a pulp of a desired flow characteristic has been achieved, the control unit acts to open valve 27, to allow pulp to pass into the first barrel 28 of the extrusion arrangement 26.

The pulp is refined in the extrusion arrangement 26. The screw 29 is rotated and the pulp is driven along the screw under pressure. The frictional contact between the particulates of the pulp, the internal walls of the barrel 28 and threaded surface of the screw 29, under

pressure as the screw rotates, breaks down the pulp, effectively grinding down the particulates of the pulp. As the screw rotates, pulp matter is forced along the axis of the first barrel 28, and in to contact with the reaction surfaces formed by the left hand end wall of the barrel 28 and the walls of the constriction formed by the conduit 28A, as well as against the other internal walls of the first barrel 28. As the pulp is urged against the reaction surfaces, to push the pulp through the conduit 28A and into the second barrel 30, a pressure builds in the first barrel 28, which causes the pulp present in the first barrel 28 to be compressed. As a result of this compression, liquid is squeezed from the pulp.

Therefore, the rotation of the screw converts the pulp to a refined fibrous material having a more consistent particulate size and reduced moisture content.

As the liquid is squeezed out of the pulp, it drains through the slots 31 on the base 33 of the first barrel 28, under gravity, and is collected in the tray 32, for reprocessing, as will be described in more detail below.

The drainage slots 31 are arranged to cooperate with the screw 29 for limiting the passage of the pulp material through the drainage means. In particular, the slots 31 are arranged so that liquid drains from the chamber 18 in a substantially opposite direction to the effective direction of travel of the pulp material. Hence, as the pulp is driven towards the conduit 28A, the passage of solid material down through the drainage slots 31 is substantially obviated.

As the screw 29 continues to rotate, refined pulp material gradually enters the second barrel 30 of the extrusion arrangement 26. Organic binders, for example starch, are introduced into the second barrel 30, for binding the fibres of the refined pulp. As the screw rotates, the binder is gradually worked into the refined pulp, which passes further along the screw 29, and then is moved through the conduit 52, under pressure from the downstream flow of material in the barrel arrangement 26, to the press apparatus 54.

In the press apparatus 54, the bound pulp passes through the rollers 56 to form and mould the pulp into a desired paper web. During passage through the rollers 56, the heater

portion 38 of the engine dries the web. The dried web then passes through the calender, where it is pressed to form a continuous wipe of a desired smoothness.

Finally, lengths of the recycled wipe can be cut using the cutter 62 and withdrawn from the unit 10, as required.

As referred to above, the liquid passing to the collecting tray 32 from the first barrel 28, during refining of the pulp, is collected for reprocessing as follows. The water passes into the sub-tank 35 and is heated by heater 36 to a temperature of over 100 degrees centigrade, to evaporate the collected water. Thereby, ink and other solids are separated from the processing water. The evaporated water is condensed by the condenser portion 37 of the free piston sterling engine and passes through the outlet conduit 40 to the sediment tank 42. Residue from this evaporation and condensation process is left in the sub-tank 35 or sediment tank 42. The water collected in the sediment tank can then be re- circulated to the water tank 24, through the return conduit 44, by the pump 46. As the water is pumped through the conduit 44, it passes through the optical sensor 48. A change in the refractive index of the water is indicative of an increase in the solid content of the water, to alert the user that the processing water in the tank needs to be replaced.

The recycling apparatus described above is advantageous in that it serves as a paper shredder and waste paper receptacle, with the additional ability to recycle waste paper. In the above described embodiment, the unit is adapted for converting waste paper into wipes, for example for laboratory use or for use in kitchens or for general cleaning purposes, or for use as toilet paper. It will be appreciated that the invention will also have similar advantages in schools, hospitals and prisons, as well as on a domestic level. In alternative embodiments, a unit in accordance with the invention may be adapted to produce other products like a compacted paper block for burning and similar use, or to produce packaging.

The micro-scale recycling apparatus in accordance with preferred embodiments of the invention is advantageous in that it is able to bleach and sterilize the paper to be recycled using ozone, without the use of standard chemicals, and without producing harmful

effluent typically associated with the art. The preferred unit is also further advantageous in that it is configured to recycle its own processing liquid, without the need for a constant mains supply of water, for example.

Turning now to Figure 4, an alternative embodiment of a screw barrel arrangement for use in a recycling apparatus in accordance with the invention will now be described, indicated generally at 100. ha this embodiment, the arrangement 100 includes first and second screw chambers 102, 104, with the first screw chamber 102 arranged above the level of the second screw chamber 104, as can be seen clearly in Figure 4.

The first screw chamber has upper and lower walls 106,108, first and second end walls 110,112 and two side walls (not indicated). An inlet 114 for the chamber 102 is provided in the upper wall 106 adjacent the left hand end of the chamber 102 as viewed in Figure 4. The inlet 114 is provided for coupling the arrangement 100 to the first processing chamber of a unit in accordance with a preferred embodiment of the invention, such as the chamber 18 described above with reference to the unit 10. Hence, the screw barrel arrangement 100 can be easily incorporated into the recycling unit 10 described above.

In this embodiment, however, an alternative form of first processing chamber is illustrated, indicated at 116. The chamber 116 is configured for receiving shredded or otherwise broken down paper material through an opening 118. A source of ozonated water 120 is provided in communication with the chamber 116, via a spray nozzle 122, for selectively spraying ozonated water onto matter present in the first chamber 116, for bleaching and sterilising purposes. The chamber 116 is also adapted to be connected to an auxiliary liquid source, such as the water tank 24 described with reference to Figure 2, for producing a mixture from the paper and liquid, for converting to a pulp of the required consistency.

A motor driven blender 124 is mounted in the bottom of the chamber 116, having a plurality of angled rotor blades 126. These blades 126 are provided for blending a

mixture of paper material, ozonated water and liquid from the auxiliary liquid source.

The blades 126 are configured to blend the paper material in a manner similar to food processor, so as to form a pulp mixture from the paper material and processing liquids.

The blender 124 includes internal means for monitoring the viscosity of the pulp mixture, for producing a pulp mixture of a predetermined consistency. As can be seen in Figure 4, the bottom wall of the chamber 116, which is indicated at 128, is inclined to encourage the pulp mixture to move under gravity towards the outlet 130 of the first chamber 116, in the bottom right hand corner of the chamber as viewed in Figure 4.

Control means in the form of a solenoid valve 132 (corresponding substantially to the solenoid valve 27 described above) is provided between the outlet 130 of the first processing chamber 116 and the inlet 114 of the first screw chamber 102, for regulating the feed of the pulped material into the screw barrel arrangement 100.

Returning now to the description of the first screw chamber 102, an outlet 134 is formed in the lower wall 108 of the chamber 102, adjacent the left hand end of the chamber 102 as viewed in Figure 4. The outlet 134 is arranged for the passage of pulped material downwards from the first screw chamber 102, as will be described in more detail below.

A first screw device 136 is provided in the first screw chamber 102. The screw device 136 is mounted on a rotatable shaft 138 extending through the chamber 102. One end of the shaft 138 is rotatably received in a bushing 140 adjacent the left hand end of the chamber 102 as viewed in Figure 4. The other end of the shaft 138 extends through the end wall 112 at the second end of the chamber 102, to the right as viewed in Figure 4.

The screw device 136 is arranged for receiving pulped material from the inlet 114. The screw device 136 has a threaded outer profile, so as to define a plurality of troughs 142 along its length when viewed in cross-section, as shown in Figure 4. The profile of the screw device 136 is configured so that the width of the troughs 142 decreases along the axial length of the screw device 136, from the right hand end to the left hand end as viewed in Figure 4. Hence, the volume of pulped material that can be accommodated by the screw device 136 at its right hand end, i. e. in the area directly adjacent the inlet 114, is

greater than that the volume of pulped material that can be accommodated at the left hand end of the screw device 136, as viewed in Figure 4.

The pitch of the screw device 136 is configured for urging pulped material towards the outlet 134 of the first chamber 102, i. e. from right to left as viewed in Figure 4.

The maximum diameter of the screw device 136 is substantially constant along its length and is of a dimension selected for close fitting cooperation with the adjacent portions of the internal walls of the first chamber 102, so as to be almost in frictional contact with the walls. However, it will be appreciated that the spacing between the screw device 136 and the upper and lower walls 106,108 has been exaggerated in Figure 4 for illustrative purposes.

As can be seen in Figure 4, the screw device 136 extends within the first screw chamber 102, substantially between the right hand end of the chamber 102 and the outlet 134. A piston 144 is arranged having an end face 146 at a working clearance, in an inoperative or rest condition, from the left hand end of the screw device 136 and is biased into the rest position shown in Figure 4 by a spring 148. In the rest position, the piston 144 covers the outlet 134, so as to prevent matter from falling through the outlet 134 to the second screw chamber 104. It will be appreciated that the end face 146 of the piston 144 provides a spring-biased reaction against the passage of pulped material being driven along the screw device 136. However, as more material is driven along the screw device 136 against the end face 146, a build up of pressure occurs, in response to the reaction from the piston and in response to the decrease in pulp-bearing capacity of the screw device 136 along its length towards its left hand end. The increase in pressure causes the pulped material within the troughs 142, in particular towards the left hand end of the screw device 136, to be compressed, so as to squeeze out liquid from the pulped material.

At a predetermined pressure, the biasing force of the spring 148 on the piston 144 is overcome, so that the material driven against the end face 146 of the piston 144 pushes the piston 144 backwards, to the left as viewed in Figure 4. The material directly adjacent the piston 144 is then able to fall from the screw device 136, down through the outlet 134

and into the second screw chamber 104. It will be appreciated that this build up of pressure and movement of the piston 144 to prevent and then enable material to fall into the second screw chamber 104 will continue in a cyclic manner, during the processing of the pulped material in the first screw chamber 102.

A plurality of angled slots 150 are provided in the lower wall 106 of the first screw chamber 102, for allowing liquid to drain out of the first screw barrel 102. The slots 150 correspond substantially to the slots 31 described above with reference to Figure 3 and extend rearwardly at an angle of 45 degrees, in the opposite direction to the pitch of the screw device 136. Hence, as the screw device 136 drives pulp mixture from right to left as viewed in Figure 4, the passage of pulped material through the slots 150 is limited.

A collecting tray 152 is provided beneath the first screw chamber 102, for collecting liquid or matter passing through the slots 150, for reprocessing and recycling in a manner similar to that described with reference to Figures 2 and 3, for example.

The second screw chamber 104 includes a motor driven shaft 154 extending through the chamber 104 and being rotatably mounted in a pair of bearings 156. As can be seen in Figure 4, a plurality of mixer blades 158 are mounted along the right hand half shaft 154.

The blades 158 are configured for driving the material to the left as viewed in Figure 4.

Reservoirs 160 for binder chemicals and perfume chemicals are provided beneath this right hand portion of the shaft 154. The chemicals are introduced via spray nozzles 162, so as to bind and add perfume to the material being processed by the mixing blades 158.

The left hand end of the chamber 104, as viewed in Figure 4, includes a second screw device 164, which is arranged for collecting the material from the mixer blades 158. The screw device 164 includes a threaded outer profile having a pitch configured for urging the bound and perfumed material out through an outlet 166, for further processing as desired.

As can be seen from Figure 4, the two shafts 138, 154 associated with the first and second screw chambers 102,104 are coupled to a belt drive 168 and motor 170, for rotating the shafts, when required.

The operation of the arrangement 100 will be clear from the above description and the description of the embodiment shown in Figures 2 and 3, so will not be described further.

Although the invention has been described with reference to use in recycling paper material, it will be readily apparent to the skilled addressee that the screw barrel type arrangements described above, having particular regard for Figure 3 and the alternative arrangement shown in Figure 4, are suitable for use in other forms of paper making apparatus. For example, the arrangements described with reference to Figures 3 and 4 can be used for processing not only pulps created from recycled paper materials but also for processing pulps created from raw paper making materials. In each case, the screw device for driving the pulped material is arranged in its chamber for squeezing liquid from the pulped material and for refining the pulp prior to further processing.

It will also be appreciated that the first processing chamber shown in Figure 4 and indicated at 116, is ideally suited for receiving raw paper making materials and can be coupled to a water source or the like, such as a liquid tank, for use in creating a pulp mixture from the liquid and the raw materials. In such instances, the drainage means in the screw chamber can be arranged in flow communication with the first processing chamber, either directly, or via a liquid tank, as referred to above. The chamber 18 in Figure 2 is also suited for this purpose.

The use of the compact screw type devices in apparatus in accordance with preferred embodiments of the invention, for processing and refining a pre-blended mixture of liquid and paper materials or the like, is of particular advantage in enabling the apparatus to be incorporated into small, non-industrial scale paper recycling units or paper making units.

The applicant hereby reserves the right to seek independent protection via one or more divisional applications derived from this application, for the screw barrel arrangements described above, either for use in recycling apparatus or for other paper making processes and the like.