WO2012102619A2

WO2012102619A2 - A materials processing device and method

Info

Publication number: WO2012102619A2
Application number: PCT/NO2012/000007
Authority: WO
Inventors: Philip John Risby
Original assignee: Agroplas Asa
Priority date: 2011-01-24
Filing date: 2012-01-24
Publication date: 2012-08-02
Also published as: WO2012102619A3

Abstract

A materials processing device comprises a chamber (101) having a first chamber region (101b) with a substantially circular inner wall (202) and being connected to materials feeding means (101a; 510), and a second chamber region (102) fluidly connected to and arranged below the first chamber region and having a downwardly extending frusto-conical shape and a bottom opening (1 16). A gas exhaust channel (1 10) is arranged concentrically with the chamber axis (c-c) and extending a distance into the chamber. The device comprises a plurality of more nozzles (501), each nozzle having an inlet (512), an internal bore and an exit opening (502a; 502b) in fluid communication with the first chamber region (101b), and a pulse generator (504, 503; 505, 507, 508) configured for imparting pressure pulses on a gas (F) flowing through the nozzle. In operating the device, pressure pulses are imparted on the gaseous flow (F) flowing through the nozzle and the resulting pulsed gaseous flow (E) is ejected tangentially into the first chamber region (101b) in order to generate a rotary array of vortices within t he chamber. Typically, the device and method are useful for e.g. drying, separating, pulverizing and particle coating.

Description

A materials processing device and method

Field of the invention

The invention generally concerns material processing, and in particular to a device and a method for processing materials using vortex air-flow. More particularly, the invention concerns a device as set out in the preamble to the independent claim 1 and a method as set out in the preamble to the independent claim 9.

Background of the invention

The double eddy cyclone is well known and has for several decades been a standard component in e.g. separators and dust collection equipment. As defined in

Wikipedia, cyclonic separation is a method of removing particulates from an air, gas or water stream, without the use of filters, through vortex separation. Rotational effects and gravity are used to separate mixtures of solids and fluids.

A high speed rotating (air)flow is established within a cylindrical or conical container called a cyclone. Air flows in a spiral pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream through the center of the cyclone and out the top.

Larger (denser) particles in the rotating stream have too much inertia to follow the tight curve of the stream and strike the outside wall, falling then to the bottom of the cyclone where they can be removed. In a conical system, as the rotating flow moves towards the narrow end of the cyclone the rotational radius of the stream is reduced, separating smaller and smaller particles. The cyclone geometry, together with flow rate, defines the cut point of the cyclone. This is the size of particle that will be removed from the stream with a 50% efficiency. Particles larger than the cut point will be removed with a greater efficiency, and smaller particles with a lower efficiency.

The cyclonic vortex principle is also used in the Sturtevant Micronizer^®, a jet mill (fluid energy mill) employing compressed air or gas to produce particles less than one micron. Inside the Micronizer, precisely aligned jets create a vortex. Material is fed into this vortex along an engineered tangent circle and accelerates. High-speed rotation subjects the material to particle-on-particle impact, creating increasingly smaller fines. While centrifugal force drives large particles toward the perimeter, fine particles move toward the center where they exit through the vortex finder.

Many industries place heavy demand upon energy resources to pulverize and dry various materials. Examples include drying silica sand, sludge, slurries, food wastes, silts and manures. Other industries require separation, segregation and careful disintegration of feed materials, examples of which are clays, eggshells, carpet fibers and other minerals. In addition to the above generic examples, the state of the art includes US

2002/0027173, CA 2 367 908, CA 2 357 938 and WO 00/56460, all by Polifka. These publications relate to a material grinding apparatus, which uses compressed air to grind solid material to micron-size particles and subsequently uses cyclonic motion to separate compressed air and ground material. The apparatus is primarily used to grind and dry the solid materials including solid wastes. The ground material is then available for appropriate further applications. The ground solid waste material with reduced volume and weight need further disposal using current available practices. The apparatus is also marketed and sold under the trade name Windhexe.

The state of the art also includes US 6 412 716 (by Robinson), which relates to particularly pulverization and dehydration of municipal sludge using cyclonic device. The device uses high-speed air to disintegrate the sludge particle and concurrently dehydrate the sludge through dehumidification and by increasing the surface area through disintegration. The air and pulverized material is separated in the cyclone due to centrifugal and gravitational forces acting on the solid particles and vortex motion of the air. The exhaust air and pulverized and dried municipal sludge further need sterilization to remove pathogens. The sterilized, dehydrated and disintegrated sludge needs to be disposed in the landfill.

The state of the art also includes US 2004/0182957 (by Gomez), which relates to pulverizing and drying solids using a vortex machine. The machine has two air fans at the inlet and outlet to cause vortex formation within a tubular device. The solids are injected in the tube and intense vortex action causes solid material to interact with high impact causing them to pulverize. Microwave energy is introduced in the pulverizing section of the device to further intensify the vortex action. The coarser solids are removed through built-in screen, and finer solids and air are exhausted. Air/solid fines separation is further required. The separated solids need further appropriate disposal.

Other publications describing the aspects of the jet mill and micronizer technology include US 4 248 387 (by Andrews) and US 5 236 132 (by Rowley).

The present applicant has devised and embodied this invention to overcome shortcomings in the prior art and to obtain further advantages.

Summary of the invention

The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

It is thus provided a device for processing materials by intimate contact with a plurality of gaseous streams, comprising a chamber having: - a first chamber region with a substantially circular wall and being connected to material feeding means;

- a second chamber region having a substantially circular inner wall and being fluidly connected to and arranged below the first chamber region; and

- a third chamber region fluidly connected to and arranged below the second chamber region and having a bottom opening through which solid may be discharged; and

- a gas exhaust channel arranged concentrically with the chamber axis connected to the upper extremity of the chamber and extending a distance into the chamber, characterized in that the device further comprises one or more pulse generators configured for imparting pressure pulses on a gas flowing through a plurality of nozzles, each nozzle having an inlet, an internal bore, and an exit opening in fluid communication with the second chamber region, and where each nozzle and/or exit opening is configured and arranged such that the nozzle exit gaseous flow enters the second chamber region tangentially or at an acute angle to the chamber inner wall.

In one embodiment, the pulse generator for each nozzle comprises a member extending a distance into the nozzle bore, thus defining a nozzle-internal orifice and a cavity.

In one embodiment, the pulse generator for each nozzle comprises a first channel for supply of a second gas, fluidly connected to a chamber, and wherein the chamber is fluidly connected to a second channel having an opening inside the nozzle, adjacent to and before the exit opening.

In another embodiment, the pulse generator comprises a pulsejet engine, ejecting a high-pressure pulsed gaseous flow into the nozzle or nozzles.

The first chamber region may have a shredding member for treating the materials before they enter the second chamber region. In one embodiment, an end of the exhaust channel extends into the second chamber region and/or the first chamber region, and comprises a plurality of vertical tubes.

The third chamber region may have a downwardly extending frusto-conical shape and may optionally include a concentrically arranged inner sieve, arranged so as to define a frusto-conical annulus between the sieve and the chamber inner wall. In one embodiment, a first annular weir is arranged on the internal wall between the second chamber region and the third chamber region, and/or a second annular weir arranged on the internal wall between the first chamber region and the second chamber region.

It is also provided a method of processing materials by intimate contact with a plurality of gaseous streams in a device according to the. invention, comprising the feeding of a plurality of gaseous flows into the second region, whereby a primary vortex and a secondary vortex are generated in the second chamber region and the third chamber region; and feeding a feedstock of a material or a mixture of materials into the chamber. The method is characterized by imparting pressure pulses on the gaseous flow flowing through the nozzle and ejecting the resulting pulsed gaseous flow tangentially or at an acute angle to the chamber wall into the first chamber region in order to generate a sheet vortex along the wall or the first chamber region.

In one embodiment, the feedstock is introduced into first chamber region and optionally also into the second chamber region.

In one embodiment, the pressure pulses are generated by feeding the gaseous flow into a nozzle, past a restriction and into a cavity, so as to introduce turbulence in the cavity in the form of Shockwave pulses.

In one embodiment, the pressure pulses are generated by feeding the gaseous flow into a nozzle, and in addition feeding an independently controlled pulsed secondary gaseous flow into a cavity having an outlet channel which is narrower than the inlet channel, and the outlet channel having an opening adjacent to the exit opening.

In one embodiment, the pressure pulses are generated by a pulsejet.

The invented method is useful for processing materials comprising one or more of the members of a group comprising of: very hard solids, minerals, clays, wastes, contaminated liquids, biomass, grains, sludge, slurries, glass, paper, wood, plastics, sand, chemicals, and carpets.

The invented method is useful in processes comprising one or more of the members of a group comprising: drying, pulverizing, moisture removal, separation, flash cooking, gasifying, disintegration, and particle coatings.

The invention provides an efficient device for processing a wide variety of materials by means of a pulsed airflow to a cyclonic chamber. The materials processed may include very hard solids, minerals, clays, wastes, contaminated liquids, biomass, grains, sludge, slurries, glass, paper, wood, plastics, sand, chemicals, carpets and more, and the range of processes that may be applied within the device include drying, pulverizing, moisture removal, separation, flash cooking, gasifying, disintegration and particle coatings.

The advantages of the invented device over currently available systems include capability to process materials that currently cannot be processed, such as separation of membranes from eggshell wastes, separation of carpet fibers from bitumen backing, rapid coating of fine particles with metals, and more.

Additionally, for other applications, this device offers significant reduction of energy consumption, multiple processes in one step, lower operating costs due to reduced consumables, high reliability, and unique performance for some feeds and processes not currently available in commercial production environment by other technologies.

Another advantage of this device is that it uses relatively low-pressure air as its motive force, and when heat may be also of advantage in some processing conditions, it can use low-grade heat, enabling the device to integrate with such systems that may produce waste heat and excess process air. For example the device integrates well with CHP (combined heat and power) turbine installations, resulting in the potential for significant improvements in energy efficiency of a complete integrated system.

The invention is capable of significantly reducing the energy consumption of processing materials, reducing process steps, reducing operating cost and increasing reliability.

The invention makes use of the multiplex of forces encountered by encouraging a pulsing flow of air to form into a rotating array of natural vortices constrained by an enclosure.

Additional energy may be supplied to the rotating air in such a manner as to enhance the desired effect. By means of vortex action, the device may used for drying, water separation, moisture removal, particle size reduction, microniszation, flash cooking, gasifying, feed material separation, disintegration, and particle coatings, or for two or more of these processes simultaneously.

The invented device and method is used in conjunction with a chamber, similar to the shape of a cyclone, so formed as to encourage the formation of a double vortex, consisting of a primary vortex in the main body of the chamber and a secondary vortex that passes through the center of the principal vortex to exit in an upper exhaust port.

The chamber has a circular cross-section that may incorporate vortex inducers such as Helmholtz resonators, spiraling grooves in the chamber wall, or axially oriented, narrow slits.

The chamber is supplied with high velocity pulsed airflow by means of a plurality of nozzles mounted on the outer wall of the chamber. The airflow may be pulsed by any one of a number of means including pulsing caused by cavities within the nozzle or pulsing caused by Helmholtz resonators positioned at or near the outlets of the nozzles.

In one embodiment, each nozzle may be supplied with a secondary high-pressure low-volume air supply that -may be independently controlled so as- to provide- a mechanism controlling the pulsation of the main body of air flow. The primary air supply may be at very low pressure (< 5 psi), whereby the secondary air supply entrains and enhances the effects of the primary air supply.

The air may be supplied by standard air supply means such as blowers, fans or compressors. In some embodiments, warmed air from a low-pressure high volume air supply may be supplied through one or more nozzles, or a means of applying heat to the primary air may be incorporated.

In some embodiments, the primary air supply is provided by means of a pulsejet system operating from fuel gas such as propane, or liquid fuels such as diesel, petrol or kerosene.

The nozzles are designed and arranged so as to create an additional third vortex in the form of a sheet vortex along the walls of the chamber, either by means of the design of nozzle form, or by use of the high-pressure secondary air supply or in other embodiments by means of the shape of channels cut into the walls of the chamber (irregular chamber surface design).

In another embodiment of the device, the nozzles are designed to include the principles of Hilsch tubes, such that the air is cooled upon exit into the chamber, assisting the processing of temperature sensitive soft or elastic materials such as plastics.

The chamber has three distinctly defined zones or regions, an upper slower motion region, immediately above the plane of the nozzles, a high speed region formed by the area in which the nozzles discharge the high speed motive air, and a lower region which may be conical in shape with either concave or straight sides, in which processed materials are separated from the main air stream.

In one embodiment of the device, a removable and replaceable liner is fitted to or near the walls of the chamber, which may provide either the source material for particle coatings or an anti-abrasive layer to prevent abrasion by some hard feed materials. For sticky materials, such a liner may prevent feed materials from sticking to the wall of the chamber before being processed by the high velocity air.

In one embodiment of the device, the walls of the chamber are fitted with vertical channels designed and shaped so as to create additional turbulence enhancing the sheet vortex produced by the nozzles, further assisting the processing of soft and elastic materials such as plastics.

In one embodiment of the device, annular discs or weirs may be inserted between different sections of the chamber to increase the residency time in different sections of the process. The benefits of such disc may include improved moisture removal or means to classify -the particle size in the output port. In one embodiment of the device, the upper walls of the chamber are fitted with movable metal spikes or metal half tubes, or vanes, so as to increase turbulence, redirect the process material and control airflows within the upper chamber relative to other chambers.

One or more feed material ports are provided in one of two positions, depending upon the feed material and the desired process. In one embodiment, the feed materials ports are located in the upper chamber top plate. In another embodiment of this device, the feed material ports are located in the chamber walls, immediately behind the nozzles or as may be the case, incorporated into the structure of the nozzle. Other positions for the feed port may also be considered for some materials.

A processed materials exit port is fitted to the lower extremity of the cone permitting the processed material to be collected with or without an airflow.

The processed materials exit port may be fitted with an expansion chamber and processed material collection means.

The processed materials exit port may be fitted with a classifier to provide a further materials separation stage.

The processed material exit port may also be fitted with air nozzles to circulate the processed material differentiating between component fractions of the processed material, thereby permitting collection of different fractions at different ports.

An air exhaust port is fitted centrally and concentrically to the upper region, in such a manner as to permit exhaust air to be removed. A tube is fitted to the exhaust port in such a manner as to extend to an adjustable extent into the upper chamber.

Within this tube are a number of smaller tubes, fitted internally in such a manner as to cause the vortex motion and therefore processing energy to remain in the chamber and not be passed into the exhaust air output flow.

The exhaust port may be ducted to an extractor fan and filtration systems.

In one embodiment of this invention, a magnetron and waveguide is fitted such that microwaves are directed into the upper chamber region to impart additional energy into the material being processed.

The first object of this invention is to process material in as energy efficient a way as possible, thereby reducing the negative impact on the environment of current processing systems.

The continued demand to increase efficiency, especially efficiency in the use of energy is well known and needs no further explanation. In an example of drying silica sand, tests have demonstrated that wet sand dried using state of the art thermal dryers is expected to consume about 186 kW per ton. The invented device, drying the same amount of sand and removing the same amount of moisture, has been shown to consume only 30 kW per ton. This is achieved using only very low-pressure air (2 psig) in readily achievable volumes. An energy saving of nearly 85% has been demonstrated.

Numerous other examples have been shown for other materials.

The second objective of this device is to provide unique processing of certain feed materials at a commercially viable scale of operation.

In an example of processing fresh eggshells, it has been demonstrated that the device rapidly separates the calcium compound of the eggshell from the membranes and any egg-white remains, providing an output of clean dry powdered eggshell flour and cooked eggshell membrane and egg-white. Several research institutions are currently developing ways to process eggshells so as to achieve the results noted above.

In another example, the device has been used to process clay shreds, wherein clay platelets of order of less than 2 microns, are naturally hexagonal shaped plates. Conventional drying and grinding damages these delicate hexagonal plates, resulting in a loss of the properties valued by clay end users. This device has been shown to produce considerably less clay platelet damage and therefore enhance the value of the dried clay. At the same time, it as been shown that this device also offers an energy saving or around 33% over conventional pin mill and hot air clay processing methods.

Other examples have been shown for other materials.

The third objective of this device is to provide a rapid and economical method of coating each and every particle of certain feed materials.

In an example of coating particles, a liner of iron was used to process silica sand. Each particle of sand was coated with a partial layer of iron. A review of iron coated silica powder has been made by the University of East Anglia, using an electron-scanning microscope. Iron coated silica particles have been found to be of benefit for the remediation of contaminated ground waters.

Various applications and configurations of the device will now de described.

Configuration for drying:

Removing moisture, water or other liquids from feed material has been found highly effective by the mechanical means used in this device. In the case of drying materials where water is bound to the surface of the feed material by means of surface tension, an enormous reduction in required energy is observed compared with thermal drying. Savings of up to nearly 85% of energy consumption have been measured. In cases where moisture is bound by more powerful forces or where high capillary effects may be present, energy savings of around 50% have been measured. In cases where extreme binding forces may exist between the feed material and the bound moisture, an increase in air temperature or the presence of microwave energy has been shown to improve performance, maintaining overall energy consumption improvements.

For drying applications the device is configured such that the air velocity is increased to a point just before unacceptable particle size reduction takes place. To further increase drying capacity, the nozzles can be configured to increase the volume of air flow without increasing the air-flow speed.

For some feed materials it is required to provide a plastic liner to the chamber walls.

Configuration for particle size reduction:

This invention can readily provide output product particles in the size range of 100 micron or less, down to the submicron particle size. The smaller the desired particle sizes, the higher the required nozzle air exit velocity.

To reduce the energy consumed, the air flow volume may be reduced and air-flow velocity increased. This requires higher air pressures from the air supply source and lower volumes.

Configuration for gasifying:

The ultimate limit of size reduction is when the particle size is smaller than is detectable. In these conditions the air feed pressure is increased, the high pressure air feed to the nozzles is also increased and the cone separator is closed.

Configuration for flash cooking:

The pulsed air from the nozzles form standing shock waves within the primary vortex. It has been observed from processing eggshells that egg whites were cooked in an extremely short period of time. It has been observed that relatively high instantaneous temperatures exist in the vortex that can be used for flash heat treatment of some materials.

Configuration for material separation:

The invention is capable of processing feeds with differing mechanical properties in different ways. The effect of air of the vortex on low density high surface area materials is lifferent than. that of high density compact smooth. particles. The device may be configured, by means of the many embodiments described, such that multiple component feed may be separated and the individual components processed in different ways.

Examples of this are separating carpet fibres from backing material, glass from plastics, soft metals from stone and more.

Configuration for disintegration:

The device can be configured to process materials such as clay, which is composed of micro plates of hexagonal form. The device further creates a static charge that can interact with charges present on the particles of feed materials causing separation of densely packed feed materials.

In general for disintegration, air feed pressures and air velocities should be limited to the lower end of the range, otherwise damage of the material may result. For clay, maximum air feed pressure should be less than 9 psi.

Configuration for coating:

This invention is capable of coating feed particles by the use of a sacrificial liner material, or other suitable component such as sacrificial rods or bars, inside the chamber in the nozzle section. When the feed material is silica sand, and the liner material is iron, the output product is iron-coated silica. Likewise other materials produce other results. In this embodiment, the nozzles are fed with low pressure air feed and the chamber wall profile is smooth, permitting the feed material to abrade against the chamber wall in the nozzle region thereby picking up a coating of the material of the sacrificial components.

Brief description of the drawings

These and other characteristics of the invention will be clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached schematic drawings wherein:

Figure 1 is a perspective view of an embodiment of the device according to the invention, defining also a longitudinal central axis c-c of the device;

Figure 2a is a sectional view in a plane perpendicular to the central axis, in the nozzle region;

Figure 2b is a sectional view similar to that of figure 2a, showing an alternative shape of the nozzle region;

Figure 3 is a part-sectional view of another alternative internal wall configuration of the nozzle region, comprising narrow slits extending substantially parallel with the central axis; Figure 4 is a schematic sectional view similar of the nozzle region, but showing only one nozzle (for clarity of illustration), and also illustrating flow conditions in the nozzle region;

Figure 5 is a drawing similar to figure 1 , but is a transparent view, illustrating the internal arrangement of key components;

Figure 6 is a schematic sectional view along the central axis, illustrating flow conditions in the chamber (items illustrated in figure 5 have been omitted for the purpose of clarity of illustration);

Figure 7 is a schematic sectional side view of a first embodiment of the nozzle;

Figure 8 is a schematic sectional side view of a second embodiment of the nozzle; and

Figure 9 is a schematic sectional side view of a third embodiment of the nozzle.

Detailed description of a preferential embodiment

Referring initially to figure 1 , the invented device comprises a chamber 101 having three distinct operating regions: a feed region 101a, a nozzle region 101b, and a separation region 102. These regions will be described in more detail below.

A plurality of nozzles 501 (three of which are illustrated in figure 1) are mounted at regular intervals around the chamber and extend through the chamber wall in the nozzle region 101b and directed in a manner best suited to encourage a vortex within the chamber (to be described later).

When operating the device, a gas flow (typically air flow) F is fed into the nozzles 501 at low pressure and high volume. Typically, air pressures not exceeding 20 psi are suitable, with pressures as low as 1 psi serving some applications and feed materials. The lower the supplied air pressure, the less energy is consumed by the device for a given rate of air-flow. Air may be typically supplied from one or more single or multiple stage blowers (not shown), via a common manifold (not shown) and into each nozzle.

The air flow F may also be supplied to the nozzles from one or more turbines or micro-turbines (not shown). In this embodiment, the air and excess heat from a so- called Combined Heat and Power (CHP) system may be used to further enhance the processes and increase overall system efficiency. A heat exchanger may also be incorporated in the air flow F upstream of the nozzle so as to transfer either waste heat from another process or generated heat from an external source into the air flow.

The nozzle region 101b has a circular cross-sectional shape (see e.g. figures 2a and 2b), and the nozzles 501 are arranged around the nozzle region periphery and oriented such that the flows exiting the nozzles enter the nozzle region at an acute angle or a tangent to the chamber. Thus, figures 2a and 2b indicate the nozzle exit direction, and not necessarily the orientation of the nozzles per se. For example, referring momentarily to figures 7 and 8, the nozzle may be mounted to the chamber wall 202 in a radial orientation via the brackets 51 1 , but the nozzle exit slot

(reference numbers 502a and 502b, respectively) is oriented such that the nozzle exit flow E is tangential to the chamber wall 202.

Returning to figure 2b, the nozzle region 101b may optionally comprise a cross- section having multi-lead spirals 201.

Referring to figure 3, the walls of the nozzle region 101b may optionally have long and narrow cavities (slits) 301 of profile dependent upon use to further induce and strengthen the sheet vortices V. This is particularly effective for processing elastic materials such as plastics and rubber.

In one embodiment of this device, the walls of the chamber are fitted with replaceable anti-abrasion material, such as polypropylene or similar plastics

Referring to figure 4 (showing only one nozzle, for clarity of illustration), when the device is in operation and air is fed into the chamber via the nozzles 501 , the tangential orientation of the nozzles (or nozzle exit slots, as explained above) and the circular cross-section of the nozzle region generate a vertical sheet vortex V which is directed along the internal wall 202 of the chamber, and the major bulk of the high velocity air-flow is directed towards the tangent of the average vortex diameter. The nozzle arrangement thus generates a primary vortex PV, which will be discussed in more detail below.

As indicated by figures 4 and 6, the resultant air-flow from each nozzle 501 is directed into the nozzle region 101b such that a powerful primary vortex PV is formed. In the nozzle region, the chamber may be of irregular shape formed by a series of channels or grooves 301 (see figure 3) so as to induce turbulence.

The internal walls of the nozzle region 101b may be manufactured from a variety of materials, including fibreglass, steel or plastics. In addition, the walls may be fitted with removable liner depending upon the intended application and function of the device. Referring now additionally to figure 5, the feed region 101a is arranged above the nozzle region 101b and comprises a feeding inlet 104 in the chamber top plate 404. An exhaust port 1 10 - which will be described later - is arranged concentric with the central axis c-c and extends a distance into the chamber. No physical separation of these regions is desired or required; one region being entirely open to the adjacent region. However, the physical shape of the feed region 101a is always circular (not multi-lead spiral, as the nozzle region may optionally be) and with a rounded curvature 12 from walls of feed region into the top plate 404. This provides a means of feeding the feed material via centrifugal forces down the sides of the feed region and into the nozzle region.

To the feeding inlet 104 is connected one or more feed systems (not shown), these being e.g. positive screw feeders, air powered entrainment feeders, or other suitable known feed means, as required by the feed material. The feed region 101a may optionally be fitted with rasp blades or combs 1 14 to provide cleaning action for such feeds as carpet wastes, where the fibres are cleaned of backing materials and disentangled. These combs 1 14 may be of rotary design permitting fibres to be removed from the nozzle region. Other feed mechanisms may be used as appropriate for specific materials and applications.

Below the nozzle region 101b is the separation region 102, comprising a cone shaped wall of circular cross section, concentric with the central axis c-c. The cone angle is such that the performance of the separation region is optimized. Thus, the magnitude of this angle may be determined to suit the density of the feed product to be processed.

An inner cone 106 of sieve type material is in one embodiment of the device fitted concentric with the central axis c-c, i.e. concentric with the cone shaped wall of the separation region 102, such that solid particles may pass through the inner cone 106 and into the annulus between the inner cone and the chamber wall, but while retaining fibrous materials within the sieve cone. This provides the means to separate fibrous fractions from particulates, for example carpet fibres from backing material, valued in carpet recycling applications.

An annular separator weir 1 1 1 may optionally be placed between the nozzle region 101b and the separation region 102. This is particularly effective when the feed material is required to be held in the nozzle region and not 'bounced' into the separation region. Plastics, rubbers and some sludge materials typically may benefit from this embodiment.

As shown in figures 1 and 5, the lower end of the separation region 102 is fitted with a sealed but vented expansion chamber 107, permitting either atmospheric air pressure to interface with the vortex at the bottom opening 1 16 of the cone via port 108, or an air feed to be applied through port 108 and a nozzle 1 15 fitted such that the circulating air out of the separation chamber is either increased or decreased in velocity, according to the material properties and separation requirements. This results in a secondary vortex SV being redirected up inside the primary vortex PV (illustrated in figure 6) and the processed (pulverised) powder product to exit from the lower end of the separation region 102 and into the expansion chamber 107.

The expansion chamber 107 collects the powder product in a container 109, and in the case of multiple component feeds, of differing mechanical properties, it is possible to collect different product fractions at different locations in the container, with the aid of a separation cone 1 12 inside the expansion chamber 107 and or a tangential port (not shown) fitted to the container 109. The container 109 may also be fitted with, or replaced, by conventional continuous product discharging means (not shown), such as, but not limited to, a screw conveyor to continuously remove the product(s) from the device.

Air exits the chamber 101 after powder product separation, by passing up the inner, secondary, vortex SV and into the exhaust port 1 10. The secondary vortex SV is effectively stripped of angular momentum by a plurality of vertical tubes 1 03, located in a cartridge inside the exhaust port 1 10. The vertical position of the lower end of the exhaust port 1 10, holding the cartridge with the smaller tubes 103, determines the relative position of the vortices within the device, and the relative air-flows through exhaust and product ports.

Returning now to the feeding of air to the nozzle region, the low-pressure, high volume, air is conveniently divided into a number of air streams through a manifold of tubes (not shown) to feed one or more nozzles 501. Three embodiments of the nozzle 501 will now be described in more detail, particularly with reference to figures 7, 8 and 9.

Figure 7 illustrates a first embodiment of the nozzle. As an air-flow F passes into the nozzle 501 a through an inlet 512, it is directed past a restriction 504 and into a cavity 503. The restriction 504 defines a nozzle-internal orifice 514, and the cavity 503 functions as a resonator, so as to introduce turbulence in the cavity in the form of Shockwave pulses. The cavity 503 is located as close as possible to the nozzle exit slot 502a and may form a part of the slot wall. Preferably, the restriction 504 is a plate-shaped, resilient, element which will vibrate under the influence of the air flow and impart pulses to the air flow.

Alternatively (not shown) the cavity 503 may be built into or attached and coupled to the walls of the chamber such that the air flows over the cavity entrance port.

The nozzle exit slot 502a is in this embodiment in the form of a vertical slit of high aspect ratio such that the air-flow is accelerated when exiting the nozzle.. The angled lip 509 is configured to ensure tangential nozzle exit flow E. Figure 8 illustrates a second embodiment of the nozzle. An air-flow F passes into the nozzle 501b through the inlet 512 and towards an exit orifice 502b. A secondary air supply S of high-pressure and low volume is independently is fed via an opening 506 into a chamber 505 in the nozzle. The chamber 505 functions as a resonance chamber and generates turbulent Shockwave pulses, utilizing the Helmholtz effect. The high-pressure air is forced from the chamber, through a narrow exit 508 and exits through a narrow slit 507 at very high supersonic velocity. This supersonic airflow from the slit 507 entrains the lower pressure air F, accelerating the air and redirecting the high volume air into the desired nozzle exit direction at the exit slot 502b.

The nozzle effectively converts low-pressure high volume air into directionally pulsed high velocity sheet of air with a number of secondary induced vortices.

Figure 9 illustrates a third embodiment of the nozzle. Here, air is produced from a pulsejet 515 which is well known in the art. The pulsejet comprises in the illustrated embodiment a one-way intake 517 for the air-flow F and a fuel conduit 516 leading into a combustion chamber 518. The pulsejet is mounted directly on the inlet 512 of the nozzle 501 c. Pulsed air exits the nozzle 501c at exit opening 502c, at an acute angle with internal wall 202.

All embodiments of the nozzle may optionally be fitted with a materials feed port 510, located close to the nozzle exit 502a, 502b, such that the materials fed through the port 510 experience the negative pressure induced by the high velocity air flow exiting from the nozzle. This is found advantageous for feeds of liquid slurries and sludge.

Although the device and method in this section have been described with reference to three specific nozzle configurations, the invention shall not be limited to such specific nozzles but encompass variants in which a pulsed airflow is fed into the chamber, causing an interaction of vortices within the chamber.

Although the invention has been described and explained with reference to air flows, it should be understood that the invention is applicable to gas flows in general, such as, but not necessarily limited to, vapours (e.g. steam) and inert gases.

Claims

1. A device for processing materials by intimate contact with a plurality of gaseous streams, comprising a chamber (101) having:

- a first chamber region (101a) with a substantially circular wall (202) and being connected to material feeding means (104);

- a second chamber region (101b) having a substantially circular inner wall (202) and being fluidly connected to and arranged below the first chamber region; and

- a third chamber region (102) fluidly connected to and arranged below the second chamber region and having a bottom opening (1 16) through which solid may be discharged; and

- a gas exhaust channel (1 10) arranged concentrically with the chamber axis (c-c) connected to the upper extremity of the chamber (101) and extending a distance into the chamber,

characterized in that the device further comprises one or more pulse generators (503, 504; 505, 507, 508; 515) configured for imparting pressure pulses on a gas (F) flowing through a plurality of nozzles (501a; 501b; 501c), each nozzle having an inlet (512), an internal bore, and an exit opening (502a; 502b; 502c) in fluid communication with the second chamber region (101b), and where each nozzle and/or exit opening is configured and arranged such that the nozzle exit gaseous flow (E) enters the second chamber region (101b) tangentially or at an acute angle to the chamber inner wall (202).

2. The device of claim 1 , wherein the pulse generator for each nozzle comprises a member (504) extending a distance into the nozzle bore, thus defining a nozzle- internal orifice (514) and a cavity (503).

3. The device of claim 1 , wherein the pulse generator for each nozzle comprises a first channel (506) for supply of a second gas (S), fluidly connected to a chamber (505), and wherein the chamber is fluidly connected to a second channel (508) having an opening (507) inside the nozzle, adjacent to and before the exit opening (502b).

4. The device of claim 1 , wherein the pulse generator comprises a pulsejet engine (515), ejecting a high-pressure pulsed gaseous flow into the nozzle or nozzles (501 c).

5. The device of any one of the preceding claims, wherein the first chamber region (101 a) has a shredding member (1 14) for treating the materials before they enter the second chamber region.

6. The device of any one of the preceding claims, wherein an end of the exhaust channel extends into the second chamber region (101b) and/or the first chamber region (101a), and comprises a plurality of vertical tubes (103).

7. The device of any one of the preceding claims, wherein the third chamber region (102) has a downwardly extending frusto-conical shape and optionally may include a concentrically arranged inner sieve (106), arranged so as to define a frusto-conical annulus between the sieve and the chamber inner wall.

8. The device of any one of the preceding claims, further comprising a first annular weir (1 1 1 a) arranged on the internal wall (202) between the second chamber region (101b) and the third chamber region (102), and/or a second annular weir (1 1 1b) arranged on the internal wall (202) between the first chamber region (101a) and the second chamber region (101b).

9. A method of processing materials by intimate contact with a plurality of gaseous streams in a device according to any one of claims 1 - 8, comprising the feeding of a plurality of gaseous flows (F) into the second region (101b), whereby a primary vortex (PV) and a secondary vortex (SV) are generated in the second chamber region (101b) and the third chamber region (102); and feeding a feedstock of a material or a mixture of materials into the chamber, characterized by

imparting pressure pulses on the gaseous flow (F) flowing through the nozzle and ejecting the resulting pulsed gaseous flow (E) tangentially or at an acute angle to the chamber wall (202) into the first chamber region (101b) in order to generate a sheet vortex (V) along the wall or the first chamber region.

10. The method of claim 9, wherein the feedstock is introduced into first chamber region (101a) and optionally also into the second chamber region (101b).

1 1. The method of any one of claims 9 or 10, wherein the pressure pulses are generated by feeding the gaseous flow (F) into a nozzle (501 a), past a restriction

(504) and into a cavity (503), so as to introduce turbulence in the cavity in the form of Shockwave pulses.

12. The method of any one of claims 9 or 10, wherein the pressure pulses are generated by feeding the gaseous flow (F) into a nozzle (501b), and in addition feeding an independently controlled pulsed secondary gaseous flow (S) into a cavity

(505) having an outlet channel (508) which is narrower than the inlet channel (506), and the outlet channel (508) having an opening (507) adjacent to the exit opening

(502b).

13. The method of any one of claims 9 or 10, wherein the pressure pulses are generated by a pulsejet (515).

14. Use of the method of any one of claims 9 - 13, for processing materials comprising one or more of the members of a group comprising of: very hard solids, minerals, clays, wastes, contaminated liquids, biomass, grains, sludge, slurries, glass, paper, wood, plastics, sand, chemicals, and carpets.

15. Use of the method of any of claims 9 - 13, in processes comprises one or more of the members of a group comprising: drying, pulverizing, moisture removal, separation, flash cooking, gasifying, disintegration, and particle coatings.