GB2576022A

GB2576022A - Dry separation waste processing and apparatus for achieving such

Info

Publication number: GB2576022A
Application number: GB1812566.6A
Authority: GB
Inventors: Christmas Martin; Christmas Peter
Original assignee: SALVTECH Ltd
Current assignee: SALVTECH Ltd
Priority date: 2018-08-01
Filing date: 2018-08-01
Publication date: 2020-02-05
Anticipated expiration: 2038-08-01
Also published as: GB201812566D0; GB2576022B

Abstract

A bladed dry separation waste processing apparatus 1 comprises a substantially horizontal waste processing chamber 2, having first inlet 3 and outlet port 4 at respective ends and where both ports 3, 4 are arranged above the longitudinal axis of chamber 2. At least one further outlet port 5, 6 adjacent to inlet port 3 and positioned below the longitudinal axis of chamber 2 is provided. Air flow means 11 and air injection nozzles 11a, maximise the flow of air existing the chamber at the first outlet port 4. A set of first blades 13 arranged along shaft 12 which runs along the longitudinal axis of chamber 2. A set of second blades 14 are fixed along chamber 2 inner walls and blades 13, 14 each pass between each other during operation as shaft drive means 15 rotates. In operation lightweight materials which are agitated by the blade arrangement and carried by the air flow, are carried out towards port 4, whilst heavier materials exit via ports 5, 6. Metering means 3, 9, 10 may also be included as well as frame 2a and hopper 8. An aerofoiled dry separation apparatus including a screen is also disclosed as is a processing system incorporating both bladed and aerofoiled apparatus.

Description

DRY SEPARATION WASTE PROCESSING AND APPARATUS FOR ACHIEVING SUCH

Field of the Invention

The present invention relates to dry processes for separating a waste stream into its various component parts and apparatus suitable for carrying out such processes.

Background of the Invention

The use of paper is widespread. The resultant build-up of paper waste, paired with environmental concerns, has given rise to a huge industry devoted to the recycling of paper waste.

The paper recycling and de-inking processes that are generally used at present by paper mills are not 100% efficient. Therefore, whilst most of the paper recovered by these processes can be reused for making recycled paper grades, the rejects from these processes are currently land-filled. Typically the rejects from these processes include wet strength paper, plastic laminated paper and plastics.

The recycling process involves an initial pulping process wherein the paper waste is broken down in hot water at levels of between 3% and 25% solids. Using this process standard paper grades are usually fully dispersed after 30 to 40 minutes. However wet strength papers (such as labels and fruit boxes) and plastic laminated papers generally take two or three times longer to break down and disperse. As a consequence it is considered commercially expedient to disperse the majority of fibres and then reject those materials that are more difficult to process (also known as reject materials).

Traditionally these reject materials (i.e. wet strength papers and plastic laminated papers) are disposed of in land-fill. Although alternative processes are known, such processes involve the use of high powered pulping and require the waste to be left for long periods to allow the laminated plastics to separate from the paper fibres. Consequently such processes have in the past been considered commercially less attractive than the land-fill option.

-1In recent times, political and economic pressures have started to dictate that a more efficient alternative to land-fill is employed when dealing with the above mentioned reject materials. As mentioned above, typical examples of these reject materials include cardboard boxes, and in particular wet strength fibres from fruit boxes, and the plastic laminated labels and packaging plastics that are associated with modern packaging.

Due to the large volumes of paper waste that needs to be recycled each year, various machines have been developed to break down the structure of the paper waste to such an extent that it can be efficiently reused in the recycled paper industry. An example of a machine that can be used to pulverize and reduce the size of paper waste is provided in US Patent 5,887,808. The grinding apparatus show in US 5,887,808 comprises a grinding chamber with a central rotating shaft upon which are mounted breaker bars, which impart a pulverizing action on the paper waste that enters the grinding chamber such that the waste is separated into much smaller particles.

Furthermore the grinding chamber of US 5,887,808 is provided with a plurality of sub-chambers each of which has an arcuate screening member located therein. Such arcuate screening members are provided with holes which serve to filter the pulverized waste paper according to the size of the resultant particles.

Although the apparatus of the prior art can be used to process the reject material from paper waste recycling processes mentioned above it does so inefficiently. This is due to the nature of reject materials obtained from most paper waste recycling processes.

In general, reject material from current paper recycling systems tends to have a moisture content that is over 50% moisture, and levels of 65% moisture are not untypical. The high moisture content of the reject material leads to ‘blinding’ of the holes in the screening plates after a very short operational time. As a consequence the level of separation achieved is unsatisfactory.

GB2482125, which was filed by the inventors of the present invention, relates to an apparatus and associated method for processing waste. The apparatus disclosed in this patent document provides improvements on the apparatus of US 5,887,808.

-2Summary of the Invention

In the light of the need for improved processes for the dry separation of paper based waste materials the present invention provides, in a first aspect, a bladed dry separation waste processing apparatus according to claim 1 and, in a second aspect, an aerofoiled dry separation waste processing apparatus according to claim 10.

It is envisioned that the apparatus of the present invention can be used alone, or preferably in combination, to achieve dry separation of waste materials, such as paper-based waste. As such, in a third aspect of the invention, a dry separation waste processing system according to claim 16 is provided.

The present invention also provides a dry waste separation process according to claim 20.

According to a first aspect, the present invention provides a bladed dry separation waste processing apparatus comprising: a cylindrical waste processing chamber configured such that, in use, the longitudinal axis of the chamber has a horizontal or substantially horizontal orientation; said chamber having an inlet port at a first end thereof and a first outlet port at a second end thereof, and wherein both the inlet port and the first outlet port are arranged in a region of the apparatus that is above the longitudinal axis of the chamber; one or more additional outlet ports arranged in a region of the apparatus that is below the longitudinal axis of the chamber, and wherein at least one of said additional outlet ports is provided adjacent to the inlet port at the first end of the chamber; air flow control means provided at the inlet port and said one or more additional outlet ports, said air flow control means being configured to minimise the flow of air leaving the chamber via said ports and thereby maximise the flow of air leaving the chamber via the first outlet port; a first set of blades arranged with inter-blade spaces along a shaft that runs along the longitudinal axis of the chamber; a second set of blades arranged with inter-blade spaces along the inner walls of the chamber; wherein the first and second blade sets are configured so that the blades of each set can pass between the inter-blade spaces of the other blade set with a predetermined clearance when said blade sets move relative to one another within the chamber; and means for driving the relative

-3movement of the first and second blade sets so as to physically separate waste within the chamber.

The arrangement of the blades within the chamber of the bladed dry separation waste processing apparatus is such that the blades of the first blade set effectively interdigitate into the gaps between the blades of the second blade set and vice versa. By arranging the blades in this way the apparatus maximises the ‘cutting’ or ‘breaking’ surface area within the processing chamber. This arrangement greatly increases the mechanical stresses placed on the waste as it passes through the processing chamber, which enhances the extent to which the waste inputted into the apparatus is physically separated or broken down.

At the same time the air flow within the chamber, which carries the waste along, is directed primarily to the first outlet port that is located on the topside of the apparatus. This is achieved by a combination of the rotating blades and the air flow control means, which operate to minimise the escape of air from the apparatus’ other ports (i.e. inlet port and additional outlet port(s)).

Controlling the direction of the air flow in this way enables lightweight waste material separated from the inputted bulk waste, such as lightweight plastics, to be blown through the waste processing chamber and out of the first outlet port, where it is collected.

Any waste material that it too heavy to be carried by the air flow in the chamber effectively falls straight through from the inlet port to the additional outlet port located below the inlet port at the first end of the chamber, where it is collected.

Preferably the apparatus may further comprise metering means on the inlet port to control the rate at which waste is delivered into the chamber. Controlling the rate at which waste is introduced into the waste processing chamber helps to provide sufficient free space for the lighter waste material to be carried upon the air flow to the first outlet port. It also helps prevent the apparatus becoming clogged up with waste.

It will be appreciated that the plane of each blade may be configured to run substantially parallel to the plane in which the longitudinal axis runs. However,

-4preferably the angle of the blades in the first and/or second blade sets may be adjustable (e.g. by an angle of up to 90° from the original plane of the blade).

Adjusting the angle of the blades can be used to change the air flow characteristics within the chamber, which in turn alters the flow rate of the material inside the chamber.

It will be appreciated also that adjusting the angle of the blades changes the clearance between the first and second blade sets. This may be desirable depending on the nature of the waste being processed.

In addition to the additional outlet port provided at the first end of the chamber, preferably at least one of the additional outlet ports is also provided at the second end of the chamber.

In this way the waste introduced into the chamber at the inlet is separated into three separate waste streams; with the lightweight waste fraction passed out of the first outlet port, the heavy waste fraction passed out of the additional outlet port at the first end of the chamber, and the intermediate waste fraction passed out of the additional outlet port at the second end of the chamber.

Preferably each of said one or more additional outlet ports further comprises blowing means configured to deliver an upward flow of air into the chamber. Further preferably, the blowing means may comprise one or more blowers. The air flow provided by the blowing means is in a substantially upward direction, although preferably not 100% vertical in direction.

It will be appreciated that the introduction of the upward flow of air serves not only to keep the waste within the chamber agitated, but it also acts an air flow control means to prevent air from escaping the chamber via the additional outlet ports - or at very least minimise this.

Preferably the apparatus may further comprise an air injection system configured to introduce an upward flow of air into the chamber from a region of the apparatus below the longitudinal axis of the chamber.

As with the outlet blowers, the air injection system helps to supplement the air flow within the waste processing chamber.

-5Further preferably, the air flow introduced into the chamber (i.e. by the blowers and/or the air injection system) is heated so as to impart a drying effect on the waste within the chamber.

Preferably each of said one or more additional outlet ports may further comprise metering means to control the rate at which processed waste leaves the chamber via said port. This enables the rate that which the waste is supplied to the next stage of the process, which in a preferred arrangement would be the aerofoiled dry separation waste processing apparatus (see below).

In addition, the controlling the rate at which processed waste can leave the chamber determines the ‘dwell time’ of the waste material within the chamber, which controls the removal efficiency of the bladed dry separation waste processing apparatus.

Preferably, the cylindrical waste processing chamber may be arranged at an incline of between 0-15° in an upwards direction moving from the inlet port to the outlet port. This helps to enhance the separation of the heavier material from the lighter material due to gravity.

In addition, the gradual incline serves to increase the ‘dwell time’ of the waste material within the chamber, which, as noted above, controls the removal efficiency of the bladed dry separation waste processing apparatus.

According to a second aspect, the present invention provides an aerofoiled dry separation waste processing apparatus comprising: a cylindrical waste processing chamber configured such that, in use, the longitudinal axis of the chamber has a horizontal or substantially horizontal orientation; said chamber having an inlet port at a first end thereof, and wherein the inlet port is arranged in a region of the apparatus that is above the longitudinal axis of the chamber; said chamber further having at least two outlet ports arranged in a region of the apparatus that is below the longitudinal axis of the chamber, and wherein at least one of said additional outlet ports is provided at the second end of the chamber; wherein each outlet port not located at the second end of the chamber is provided with a screen that has a plurality of apertures configured to only permit waste of a particular size to exit the chamber via the associated outlet port; at least one aerofoil blade rotatably mounted about the longitudinal axis within the chamber, and wherein a clearance is provided

-6between the screen of each outlet port and said at least one aerofoil blade; and means for driving the rotation of the at least one aerofoil blade within the chamber.

Waste introduced into the waste processing chamber is agitated by the rotation of the aerofoils, which causes the waste to be lifted and dropped inside the chamber. The waste falls onto the screen that is located on the underside of the chamber. The screen is provided with apertures of a predetermined size that permit only waste particles below that size to pass through the screen to the outlet port below for collection.

The larger pieces of waste material remain in the chamber and continue to be subjected to agitation until they are either broken down to sufficiently small particles or they reach the unscreened outlet port located at the second end of the chamber. Waste leaving the chamber via the outlet port at the second end of the chamber is considered ‘screen rejects’, whereas the waste that passes through the screen to the outlet port below is considered ‘screen accepts’.

In addition to agitating the waste within the chamber to facilitate its separation, the aerofoil blades serve to prevent the screen apertures being blinded by the larger pieces of waste. The aerofoils achieve this by creating an area of lower pressure in their wake, which essentially sucks away any waste that might have become lodged on the screen - thereby keeping the screen’s apertures clear.

Preferably the apparatus may further comprise an outlet port arranged at the second end of the chamber in a region of the apparatus that is above the longitudinal axis of the chamber. By providing this additional outlet port on the upper region of the apparatus it is possible to collect lightweight waste materials that may be carried along by the air flow within the chamber in a manner similar to that carried out by the bladed dry separation waste processing apparatus disclosed above.

Preferably said at least one aerofoil blade may be mounted to a rotatable shaft by one or more arms, wherein the rotatable shaft runs along the longitudinal axis of the chamber.

Further preferably, the length of the one or more arms may be adjustable to alter the clearance between said aerofoil blade and said screen. In this way the air flow characteristics within the chamber can be varied.

-7Additionally, the angle of said at least one aerofoil blade may be adjustable. It will be appreciated that this too will enable the air flow characteristics within the chamber to be varied. Adjusting the angle of said aerofoil blade can also change the amount of negative pressure (i.e. suction) created in the wake of the blade.

Preferably the apparatus may further comprise blowers to supplement the flow of air through the chamber. Further preferably, the air flow from these blowers may be heated so as to impart a drying effect on the waste within the chamber.

As noted above, although the bladed dry separation waste processing apparatus and the aerofoiled dry separation waste processing apparatus can be used in a standalone manner, advantageously the two apparatus can be used in series to provide greater waste separation.

To this end a third aspect of the present invention provides a dry separation waste processing system comprising the bladed dry separation waste processing apparatus of the first aspect of the present invention connected in series with the aerofoiled dry separation waste processing apparatus of the second aspect of the present invention.

Preferably the inlet port of the aerofoiled dry separation waste processing apparatus is in fluid communication with one of the additional outlet ports of the bladed dry separation waste processing apparatus.

Preferably the system may further comprise shredding means configured to supply shredded waste to the inlet port of the bladed dry separation waste processing apparatus.

Preferably the system may further comprise magnetic extraction means configured to remove metals from the waste before it enters the inlet port of the bladed dry separation waste processing apparatus.

In addition to the above disclosed apparatus and system, the present invention also provides an associated dry waste separation processing method that employs a cylindrical waste processing chamber, which has an inlet port and a first outlet port located in a region of the chamber above a longitudinal axis thereof and at least one additional outlet port located in a region of the chamber below the longitudinal axis

-8thereof, said process comprising: a) introducing waste into the chamber via the inlet port; b) generating an air flow within the chamber and controlling the air flow so as to direct the air flow out of the chamber via the first outlet port; c) operating a first and a second blade set within the chamber so as to physically separate the waste within the chamber, said blade sets being configured so that the blades of each set can pass between inter-blade spaces of the other blade set when said blade sets move relative to one another within the chamber; and d) collecting processed waste streams from the outlet ports of the chamber.

It will be appreciated that the benefits provided by the following optional method step equate to those disclosed in relation to the apparatus and the system above.

Preferably the method may further comprise introducing an upward air flow into the chamber from a region below the longitudinal axis of the chamber.

Preferably the upward air flow may be introduced into the chamber either via the at least one additional outlet port, a separate air input system, or a combination of both.

Preferably the method may further comprise the step of heating the air within the chamber.

Preferably the method may further comprise adjusting the angle of the blades in the first and/or second blade set so as to adjust the air flow characteristics within the chamber.

Preferably the method may further comprise feeding waste into the chamber at a controlled rate and/or controlling the rate at which processed waste leaves the chamber via the outlets.

Preferably the method is carried out using the bladed dry separation waste processing apparatus of the first aspect of the present invention.

Preferably the method may further comprise delivering processed waste, which has been collected from at least one of the outlet ports, to the inlet of an aerofoiled dry separation waste processing apparatus according to the second aspect of the present invention for further processing; and collecting the further processed waste from the outlets of the aerofoiled dry separation waste processing apparatus.

-9Further preferably the method may comprise connecting one of the outlet ports of the cylindrical waste processing chamber to the inlet port of the aerofoiled dry separation waste processing apparatus.

Additionally or alternatively, the method may further comprise adjusting the aerofoil blade to vary the air flow characteristics within the chamber of the aerofoiled dry separation waste processing apparatus.

Brief Description of the Drawings

The present invention will now be described with reference to the preferred embodiments shown in the drawings, wherein:

Figure 1 shows a partially exposed diagram of a preferred embodiment of the bladed dry separation waste processing apparatus of the present invention;

Figure 2 shows a simplified diagram of the bladed dry separation waste processing apparatus;

Figure 3 shows a partially exposed diagram of a preferred embodiment of the aerofoiled dry separation waste processing apparatus of the present invention; and

Figure 4 shows a simplified cross-sectional end view of aerofoiled dry separation waste processing apparatus.

Detailed Description of the Preferred Embodiments

It is envisaged that the apparatus, system and method of the present invention can be used to separate a wide variety of waste streams, which include: general waste from the paper industry; single-use beverage cup recycling process rejects; anaerobic digestion process rejects; agricultural films; materials recycling facility (MRF) rejects; and mechanical biological treatment (MBT) plant rejects.

In general, it is envisaged that the apparatus, system and method of the present invention can be used to separate any fibrous based waste materials, including RDF’s (Refuse Derived Fuels) and their equivalents.

However, the present invention is considered particularly applicable to the processing of paper based waste that is contaminated with, amongst other things,

-10lightweight polymer film. Packaging commonly uses paper that has been laminated with polymer film to make it waterproof.

As a consequence, the preferred embodiments of the present invention will be described in relation to the processing of paper-based waste. With that said, it will be appreciated by the skilled person that the apparatus, system and method of the present invention are equally suitable for use in processing other waste streams.

Commonly, in order to recycle laminated paper of this type, the paper waste is subject to a wet separation process wherein it is pulped, cleaned and dried. However, whilst this process does release large amounts of paper fibre for reuse, not all of the paper fibre can be separated from the polymer film in an econimiucally efficient time scale. Typically this remaining paper fibre is disposed on with the associated polymer film (i.e. burned or landfilled).

The apparatus, system and method of the present invention provides a dry separation process that can be used to separate laminated paper of this type so that it is possible to isolate and recover the lightweight polymer material and the previously unrecovered paper fibres.

To this end the present invention provides two dry separation waste processing apparatus suitable for use in separating, amongst other things, laminated paper waste that might otherwise be disposed of because it is uneconomical to process.

The first apparatus is a bladed dry separation waste processing apparatus, an embodiment of which is shown diagrammatically in Figures 1 and 2. The second apparatus is an aerofoiled dry separation waste processing apparatus, an embodiment of which is shown diagrammatically in Figures 3 and 4.

It is appreciated that, whilst these apparatus can be used in isolation to process waste streams such as laminated paper, the two apparatus can be used in series to maximise the level of waste separation achievable.

The bladed dry separation waste processing apparatus 1 of the present invention will now be described with reference to the embodiment shown in Figures 1 and 2.

The apparatus 1 comprises a cylindrical waste processing chamber 2 that is sealed at both ends. The chamber 2 is mounted on a frame 2a, which orients the

-11longitudinal axis of the chamber in a horizontal or generally horizontal manner. Although not shown in the figures, it is appreciated that the frame 2a may orient the chamber at a slight incline of between 0-15° in an upward gradient moving from the inlet end to the outlet end of the chamber. As noted above, inclining the chamber in this way can enhance the separation of the heavier material from the lighter material due to gravity. Also, the gradual incline serves to increase the ‘dwell time’ of the waste material within the chamber, which, as noted above, controls the removal efficiency of the bladed dry separation waste processing apparatus.

The chamber 2 is preferably made from Mild or Stainless steel.

The chamber is provided with a number of ports, which enable waste to enter and leave the chamber. At a first end of the chamber is provided an inlet port 3, via which bulk waste material is introduced for processing. The inlet port 3 is arranged on the top of the chamber so that the waste can be dropped in from a hopper 8 located above the waste processing chamber.

The hopper 8 is provided with metering means 7 that control the rate at which new waste material is introduced into the waste processing chamber 2. In this way it is possible to ensure that the chamber 2 is not overfilled with waste material, which would impair the separation process.

Preferably, the control of the inlet metering means 7 is co-ordinated with the control of associated metering means 9, 10 on the chamber outlets 5, 6 so that the waste inputted into the chamber is balanced with the waste removed from the chamber via the outlets 5, 6. This helps to ensure a steady flow of waste through the apparatus.

An air flow control means (see Figure 2), preferably in the form of a valve is provided, at the inlet port to regulate the passage of air in and out of the inlet port 3. Along with air flow control means (e.g. valves) provided on the outlets of the chamber 2, the air flow control means on the inlet are operated to ensure that the air flows within the chamber from the inlet port end to the outlet port end.

Although the skilled person will appreciate that various valves could be employed to achieve the required control of air flowing into and out of the chamber, a rotatory valve is considered particularly suitable for the operation of the apparatus over an extended period of time.

-12It is envisaged that the metering means may comprised the airflow control means. That is to say, the two functions (i.e. metering of waste and control of air flow) are achieved by the same device.

At the opposite end of the chamber 2 is provided a lightweight waste outlet port 4. As with the inlet port 3, the lightweight waste outlet port 4 is located on the top half of the chamber - as can be defined with reference to the longitudinal axis that runs through the middle of the chamber.

Essentially the lightweight waste outlet port 4 is positioned so that lightweight waste material, such as the lightweight polymer materials that are separated from the laminated paper waste, is lifted up and carried along by the air flow as it moves towards the outlet port 4 generally in the upper region of the chamber.

At least one additional outlet port is provided at the same end as the inlet port 3 on the underside of the chamber 2, which again can be defined with reference to the longitudinal axis of the chamber. In the embodiment of the apparatus shown in Figures 1 and 2, the chamber is provided with two additional outlet ports 5, 6.

The first additional outlet port 5, which will be referred to as the heavy waste outlet port 5, is located underneath the inlet port 3 at the first end of the chamber. In this way heavy waste materials introduced into the chamber at the inlet 3, which cannot be carried by the air flow within the chamber 2, simply drop straight through the chamber for collection at the heavy waste outlet port 5.

In the case of paper based waste, the waste collected at the heavy waste outlet port 5 is mostly a mix of wet organic fraction (e.g. paper fibres) and denser materials (e.g. metals and heavier plastics).

The second additional outlet port 6, which will be referred to as the intermediate waste outlet port 6, is located at the second end of the chamber. In this way, the waste that is light enough to be transported along the chamber, but not light enough to be blown along the top of chamber and out of the lightweight material outlet 4, can be collected as a separate waste stream.

-13In the case of paper based waste, the waste collected at the intermediate waste outlet port 6 is generally a mix of heavier plastics, some lighter plastics, rags and some paper fibres.

Therefore, in terms of the average density of the waste collected at the three identified outlet ports 4, 5, 6, the least dense waste is collected at the lightweight waste outlet port 4 and the densest waste is collected at the heavy waste outlet port 5. Everything in between is collected via the intermediate waste outlet port 6.

As noted above, the outlet ports on the underside of the chamber are provided with metering means to control the rate at which waste is collected from the chamber via these ports. In this regard, the heavy waste outlet port 5 is provided with metering means 9 and the intermediate waste outlet port 6 is provided with metering means 10.

In order to facilitate the passage of waste through the chamber 2 an air flow is created within the chamber. Air flow control means are provided to ensure that the air flow is directed from the inlet port 3 to the lightweight waste outlet port 4. In the preferred embodiment of the bladed dry separation waste processing apparatus 1, the air flow control means are provided as blowers 16, 17 associated with the two outlet ports 5, 6 located in the underside of the chamber 2 (see Figure 2).

The blowers 16, 17 are arranged to provide an upward flow of air into the chamber via the outlet ports 5, 6. This upward flow directs the air flow within the chamber away from the outlet ports in the underside of the chamber and, in so doing, towards the lightweight waste outlet 4. This ensures that waste that is light enough to be carried by the air flow does not leave the chamber too soon.

The air flow within the chamber 2 is further supplemented by an air injection system 11 that introduces an upward air flow into the chamber via a plurality of injection nozzles 11a located in the underside of the chamber 2.

As the waste moves through the chamber 2 it is subjected to mechanical stresses by the relative movement of a first and a second blade set 13, 14.

-14The first blade set 13 is provided along the length of a central shaft 12 that is located along the longitudinal axis of the cylindrical waste processing chamber 2. The second blade set 14 is provided along the length of the chamber’s inner walls.

The blades in each set are arranged with an inter-blade spacing, the shape of which is complementary to a blade on the other blade set. That is to say, an inter blade spacing on the first blade set is complementary to the shape of a blade in the second blade set and vice versa.

This complementary configuration enables the blades in each blade set 13, 14 to pass between the blades of the other blade set 14, 13 with a predetermined clearance. In this way the blades combine to impart a smashing/cutting action on any waste material caught between the blades when they pass one another.

It is appreciated that interdigitating the blades of the two blade sets in this way maximises the smashing/cutting surface area where waste can be impacted. This increases the capacity of the apparatus to break up the waste without necessarily requiring the overall length of the apparatus to be extended.

Although the blades shown in figure 1 are triangular in shape, it is appreciated that various shapes of blade can be adopted on either blade set (possibly even different shapes in the same apparatus) provided the inter-blade spacing between the blades is such that it allows the blades of each set to pass between the blades of the other set.

It is envisaged that alternatively, or indeed additionally, trapezoidal shaped blades may be employed in the apparatus of the present invention. Typically, whatever their shape, the blades are preferably made from Mild steel; although it is envisaged that alternative materials may also be used.

In the apparatus shown in Figures 1 and 2, the first set of blades are provided on a shaft 12 that is rotatably mounted within the chamber 2. Drive means 15 are provided to rotate the shaft 12, and the mounted blades 13, within the chamber and passed the fixed second blade set 14.

However, it is appreciated that in an alternative arrangement the first blade set 13 may be static and the second blade set 14 may be configured to move around the

-15inside of the chamber walls to achieve the same relative movement between the blade sets. In a further alternative arrangement both blade sets may be configured to rotatable within the chamber.

It is envisioned that the blades in each blade set may be arranged in one or more rows along the length of the shaft or chamber wall. This is the arrangement shown in the Figures 1 and 2. However, it is also appreciated that the blades in each blade set may be arranged in different patterns, such as a helical arrangement wherein each blade in a blade set is slightly offset from its neighbours.

Although not shown in the Figures, preferably the angle of the blades in either blade set is adjustable to vary the air flow characteristics within the chamber.

In their standard orientation the blades lie in a plane that runs essentially parallel to the longitudinal axis of the cylindrical waste processing chamber 2. However, it is appreciated that the angle of the blade may be adjusted by up to 90° from this standard orientation. This may be achieved manually or automatically by way of a central control means.

It is envisaged that the central control means (not shown) may also be used to control the drive means 15, the metering means 7, 9, 10, and the air flow control means 11, 16, 17.

Referring now to Figure 2, it will be appreciated that only a portion of the blades in the first and second blade sets 13, 14 are shown for the sake of clarity.

The operation of the bladed dry separation waste processing apparatus of the present invention will now be briefly summarised.

Waste material, which has preferably been shredded, is fed to the inlet 3 via the hopper 8 at the top of the apparatus 1. This material is then steadily released into the waste processing chamber 2, whereupon a number of actions occur simultaneously:

• The relative movement of the blades in the first and second blade sets 13, 14 physically separate the different constituents of the waste as it is beaten and crushed in the small gaps between the blade edges.

• The jets of air introduced into the underside of the chamber further separate the material, suspending the lightweight elements at the top of the chamber whilst allowing the heavyweight materials to fall to the bottom.

• The air flow generated by the angle of the moving blades pushes the lightweight material along the chamber towards the lightweight outlet port 4 located at the top of the chamber.

The net result of these actions is that lightweight and heavyweight material is separated, with heavyweight material largely falling into the heavy waste outlet 5 (any that isn’t will be captured by the intermediate waste outlet 6) and lightweight material being released from the lightweight outlet 4.

Turning now to Figures 3 and 4, an embodiment of the aerofoiled dry separation waste processing apparatus 20 will now be described. The apparatus 20 comprises a cylindrical waste processing chamber 21.

The chamber 21 is mounted on a frame 21a, which orients the longitudinal axis of the chamber in a horizontal or generally horizontal manner. Although not shown in the figures, it is appreciated that the frame 21a may orient the chamber at a slight incline although in most cases chamber of the aerofoiled dry separation waste processing apparatus 20 will not be on an incline.

The chamber 21 is preferably made from Mild or Stainless steel.

The chamber is provided with a number of ports, which enable waste to enter and leave the chamber. At a first end of the chamber is provided an inlet port 22, via which waste material is introduced for processing.

Metering means (not shown), preferably with airflow control means similar to those described in relation to the bladed dry separation apparatus shown in Figures 1 and 2, may be provided at the inlet port 22 to control the rate at which waste is introduced into the chamber 21.

Along the underside of the chamber, as can be defined with reference to the longitudinal axis of the chamber, are provided a series of at least two outlet ports 23, 24 from which waste can be collected.

-17At the second end of the chamber is located an outlet port 23, which will hereinafter be referred to as the screen rejects outlet port 23. Next to outlet port 23, and closer to the first end of the chamber 21, is provided a second outlet port 24, which will hereinafter be referred to as the screen accepts outlet port 24.

A screen 26 is provided at the mouth of the screen accepts outlet port 24 to control the passage of waste material out of this port according to size. To this end the screen 26 comprises a preferably curved plate with a plurality of apertures 26a of a predetermined size. In this way the screen serves to permit passage of waste particles below a predetermined size, whilst waste particle above the predetermined size are prevented from leaving the chamber via the screen accepts outlet port 24.

It is appreciated that the apertures 26a can varied in size and shape depending on the make-up of the waste being processed and the output requirements (e.g. size range of waste allowed to go to screen rejects outlet).

The screen rejects outlet 23 is not provided with a screen.

As will be appreciated from Figure 3, both the screen 26 and the screen accepts outlet port 24 extend along a greater proportion of the chamber’s length than the screen rejects outlet 23. This is to maximise the opportunity for waste of a suitable size to pass through the screen 26 and out of the screen accepts outlet port 24.

A further outlet port 25 is provided at the second end of the chamber 21 on the top of the apparatus 20. This outlet port 25, which will hereinafter be referred to as a lightweight waste outlet port 25, provides the same role as the lightweight waste outlet port 4 of the bladed dry separation waste processing apparatus described above. That is it allows for lightweight waste materials, such as lightweight polymers, to be carried on the air flow along the upper regions of the chamber and eventually out of the chamber via the outlet port 25.

A fan 31 is provided at the first end of the chamber 21 to provide a flow of air within the chamber to help progress the waste along its length. In the embodiment shown in Figure 3, the fan 31 drives waste from the inlet port 22 at the first end of the chamber onwards to the second end of the chamber.

-18Preferably the air flow entering the chamber is heated so as to provide a drying effect on the waste as it is processed within the chamber.

Multiple aerofoil blades 28 are rotatably mounted within the chamber. The aerofoil blades 28 are attached to a central shaft 27 by way of arms 29. The central shaft 27 is rotated within the chamber by drive means 30 so that the aerofoil blades 28 move about a circular path within the chamber 21 thereby creating turbulence within the chamber.

Throughout their rotational path the aerofoil blades maintain a small distance from the walls of the cylindrical waste processing chamber 21 and the curved screen 26. As the aerofoils 28 travel in close proximity to the surface of the screen 26 they help force waste particles through the apertures 26a and then create a low pressure pulse in their wake as they pass by.

The momentary backflush action of the pulse prevents waste from building up and plugging or blinding the screen apertures 26a. Between pulses the pressure with which the waste fibres are blown into the housing keeps the fibres moving through the apertures 26a to the screen accepts outlet port 24 for collection.

It is appreciated that the angle of the aerofoil, distance from screen plate and speed of rotation all determine the amount of pulling force which keep the screen plate clear. As such, it is preferable that the angular orientation of the aerofoils 28 can be adjusted.

Also, it is also preferable that the arms 29 are adjustable so that the clearance between the screen 26 and the aerofoils can be varied. It is envisaged that a central control means (not shown) is provided to enable the operator to change these variables as needed.

In addition, the arms holding the foils are open backed, which creates a trailing low pressure area behind the arms 29 as they rotate within the chamber. This in turn creates turbulence ensuring the lightweight waste material is constantly in motion.

In this regard it will be understood that the balance between feed rate of material blown into the chamber under a slight positive pressure, turbulence within the chamber and the pulling force from the aerofoils 28 and the arms 29 all have an

-19impact on the throughput and quality of separation achieved by the aerofoiled dry separation waste processing apparatus 20.

As noted above, advantageously the bladed dry separation waste processing apparatus 1 and the aerofoiled dry separation waste processing apparatus 20 can be 5 used in series to process waste, such as paper based waste.

In a further preferred embodiment a dry separation waste processing system can be formed by connecting one of the outlet ports (preferably the heavy waste outlet port 5) of the bladed dry separation waste processing apparatus 1 to the inlet port 22 of the aerofoiled dry separation waste processing apparatus 20.

Claims

-20Claims

1. A bladed dry separation waste processing apparatus comprising:

a cylindrical waste processing chamber configured such that, in use, the longitudinal axis of the chamber has a horizontal or substantially horizontal orientation;

said chamber having an inlet port at a first end thereof and a first outlet port at a second end thereof, and wherein both the inlet port and the first outlet port are arranged in a region of the apparatus that is above the longitudinal axis of the chamber;

one or more additional outlet ports arranged in a region of the apparatus that is below the longitudinal axis of the chamber, and wherein at least one of said additional outlet ports is provided adjacent to the inlet port at the first end of the chamber;

air flow control means provided at the inlet port and said one or more additional outlet ports, said air flow control means being configured to minimise the flow of air leaving the chamber via said ports and thereby maximise the flow of air leaving the chamber via the first outlet port;

a first set of blades arranged with inter-blade spaces along a shaft that runs along the longitudinal axis of the chamber;

a second set of blades arranged with inter-blade spaces along the inner walls of the chamber;

wherein the first and second blade sets are configured so that the blades of each set can pass between the inter-blade spaces of the other blade set with a predetermined clearance when said blade sets move relative to one another within the chamber; and means for driving the relative movement of the first and second blade sets so as to physically separate waste within the chamber.

2. The bladed dry separation waste processing apparatus of claim 1, wherein the apparatus further comprises a metering means on the inlet port to control the rate at which waste is delivered into the chamber.

3. The bladed dry separation waste processing apparatus of claim 1 or 2, wherein the angle of the blades in the first and/or second set of blades is adjustable, preferably by up to 90°.

4. The bladed dry separation waste processing apparatus of claim 1,2 or 3, wherein at least one of the additional outlet ports is provided at the second end of the chamber.

5. The bladed dry separation waste processing apparatus of any of the preceding claims, wherein each of said one or more additional outlet ports further comprises blowing means configured to deliver an upward flow of air into the chamber.

6. The bladed dry separation waste processing apparatus of any of the preceding claims, further comprising an air injection system configured to introduce an upward flow of air into the chamber from a region of the apparatus below the longitudinal axis of the chamber.

7. The bladed dry separation waste processing apparatus of claim 5 or 6, wherein the air flow introduced into the chamber is heated so as to impart a drying effect on the waste within the chamber.

8. The bladed dry separation waste processing apparatus of any of the preceding claims, wherein each of said one or more additional outlet ports further

-22comprises metering means to control the rate at which processed waste leaves the chamber via said port.

9. The bladed dry separation waste processing apparatus of any of the preceding claims, wherein the cylindrical waste processing chamber is arranged at an incline of between 0-15°.

10. An aerofoiled dry separation waste processing apparatus comprising:

said chamber having an inlet port at a first end thereof, and wherein the inlet port is arranged in a region of the apparatus that is above the longitudinal axis of the chamber;

said chamber further having at least two outlet ports arranged in a region of the apparatus that is below the longitudinal axis of the chamber, and wherein at least one of said outlet ports is provided at the second end of the chamber;

wherein each outlet port not located at the second end of the chamber is provided with a screen that has a plurality of apertures configured to only permit waste of a particular size to exit the chamber via the outlet port;

at least one aerofoil blade rotatably mounted about the longitudinal axis within the chamber, and wherein a clearance is provided between the screen of each outlet port and said at least one aerofoil blade; and means for driving the rotation of the at least one aerofoil blade within the chamber.

11. The aerofoiled dry separation waste processing apparatus of claim 10, further comprising an outlet port arranged at the second end of the chamber in a region of the apparatus that is above the longitudinal axis of the chamber.

12. The aerofoiled dry separation waste processing apparatus of claim 10 or 11, wherein said at least one aerofoil blade is mounted to a rotatable shaft by one or more arms, wherein the rotatable shaft runs along the longitudinal axis of the chamber; and wherein preferably the length of the one or more arms is adjustable to alter the clearance between said aerofoil blade and said screen.

13. The aerofoiled dry separation waste processing apparatus of any of claims 10 to 12, wherein the angle of said at least one aerofoil blade is adjustable.

14. The aerofoiled dry separation waste processing apparatus of any of claims 10 to 13, further comprising blowers to supplement the flow of air through the chamber.

15. A dry separation waste processing system comprising a bladed dry separation waste processing apparatus according to any of claims 1 to 9 connected in series with an aerofoiled dry separation waste processing apparatus according to any of claims 10 to 14; and wherein preferably the inlet port of the aerofoiled dry separation waste processing apparatus is in fluid communication with one of the additional outlet ports of the bladed dry separation waste processing apparatus.

16. The system of claim 15, further comprising shredding means configured to supply shredded waste to the inlet port of the bladed dry separation waste processing apparatus.

17. The system of claim 15 or 16, further comprising magnetic extraction means configured to remove metals from the waste before it enters the inlet port of the bladed dry separation waste processing apparatus.

18. A dry waste separation processing method that employs a cylindrical waste processing chamber, which has an inlet port and a first outlet port located in a region of the chamber above a longitudinal axis thereof and at least one additional outlet port located in a region of the chamber below the longitudinal axis thereof, said process comprising:

a) introducing waste into the chamber via the inlet port;

b) generating an air flow within the chamber and controlling the air flow so as to direct the air flow out of the chamber via the first outlet port;

c) operating a first and a second blade set within the chamber so as to physically separate the waste within the chamber, said blade sets being configured so that the blades of each set can pass between inter-blade spaces of the other blade set when said blade sets move relative to one another within the chamber; and

d) collecting processed waste streams from the outlet ports of the chamber.

19. The method of claim 18, further comprising introducing an upward air flow into the chamber from a region below the longitudinal axis of the chamber; and wherein preferably the upward air flow is introduced into the chamber either via the at least one additional outlet port, a separate air input system, or a combination of both.

20. The method of claim 18 or 19, further comprising heating the air within the chamber.

21. The method of any of claims 18 to 20, further comprising adjusting the angle of the blades in the first and/or second blade set so as to adjust the air flow characteristics within the chamber.

22. The method of any of claims 18 to 21, further comprising feeding waste into the chamber at a controlled rate and/or controlling the rate at which processed waste leaves the chamber via the outlets.

23. The method of any of claims 18 to 22, wherein the separation process is carried out using a bladed dry separation waste processing apparatus according to any of claims 1 to 9.

24. The method of any of claims 18 to 23, further comprising:

delivering processed waste, which has been collected from at least one of the outlet ports, to the inlet of an aerofoiled dry separation waste processing apparatus according to any of claims 10 to 14 for further processing; and collecting the further processed waste from the outlets of the aerofoiled dry separation waste processing apparatus.

25. The method of claim 24, further comprising connecting one of the outlet ports of the cylindrical waste processing chamber to the inlet port of the aerofoiled dry separation waste processing apparatus.

26. The method of claim 24 or 25, further comprising adjusting the aerofoil blade to vary the air flow characteristics within the chamber of the aerofoiled dry separation waste processing apparatus.