FIELD OF THE INVENTION

The invention relates to an apparatus and method for cleaning and coating rubber crumb. Specifically, the invention may relate to an apparatus and method for cleaning and coating rubber crumb from waste tyres. Rubber crumb, whether derived from waste tyres or other source materials, are often dirty from environmental contaminants such as dust, grime or oil. If rubber crumb is to be used in subsequent processing steps, such as in the derivation of petroleum products, they must be coated with inoculants or catalysts, but this steep can be difficult to achieve efficiently. The inventive apparatus and method provides a solution for quick and efficient cleaning and coating of rubber crumb, optionally specifically rubber crumb from waste tyres.

BACKGROUND OF THE INVENTION

Rubber crumb, such as that derived from waste tyres, if often used in subsequent processing steps to derive useful products. Solely by way of example, rubber crumb from ground up waste tyres is often used in a series of steps with the goal of producing petroleum products such as diesel fuel. Challenges are encountered with respect to both cleaning the rubber crumb and also coating the rubber crumb in inoculants or catalysts in subsequent processing steps.

So much time and materials are wasted by the inability to coat the surface of the rubber granules sufficiently for the next step to be efficient, both cost-wise and in terms of environmental savings on energy heat and power. The result is often just to use twice as much inoculant, catalyst or additives in an often-ineffective effort to overcome this difficulty.

The first problem encountered is that lots of the rubber crumb particles are dirty from contamination and that the rubber material can be covered in dust, grime and oil or other contaminants from being on the road in vehicle tyres.

The second problem encountered is that it is often difficult to coat the rubber crumb particles effectively with inoculants or catalysts for subsequent processing steps. This can be due to the particles still being dirty from environmental contaminants and can also be due to the particles not being scrubbed sufficiently so that their surfaces are amenable to coating.

Accordingly, there is a need for a solution for processing of rubber crumb that addresses the difficulty in adequately cleaning the material and also the failure to adequately prepare the material for coating with inoculants and catalysts. This solution is needed in order to more efficiently and cost-effectively process rubber crumb for subsequently reprocessing steps such as the preparation of high-quality petroleum products.

SUMMARY OF THE INVENTION

The present inventors have developed an apparatus and method for cleaning rubber crumb and applying the catalyst or inoculant completely coating the surface in an efficient and cost effective manner.

Once the rubber crumb has been successfully cleaned and scarified and then coated in the catalyst, inoculant, or additive, the result is that the efficiency has dramatically increased and the need for using additional amounts of catalyst inoculate or additive is reduced; saving all the energy costs and associated processing costs. The other benefit is that when clean rubber crumb is placed in a refining process you then have significantly cleaner products of oil and carbon black afterwards; increasing the value by as much as 10 times as a sale commodity, saving on energy and heat costs and creating a much more reliable and robust feedstock for further processing.

At the heart of our design is this simple and robust process focused on efficiently cleaning and scarifying rubber ensuring it is fully or sufficiently coated. We realised with this innovation that we would be saving time, money and using best environmental practice, while at the same time delivering a fantastic cost effective process that could be sold and rolled out to every other company that wishes to be more effective in its activity while at same time being more sustainable by using and creating less catalysts and decreasing heat production for the same production process.

Once the tyre has been processed into tyre crumb, it is normally covered in dust, grime, oil, metal shards and other contaminants that are picked up by being on the road. The way we deal with this is very simple and innovative: first the crumb goes into a hopper which has a simple delivery system governed by an electric motor. This measures only a kilo or two of crumb into the next step of the process. The next step is that as the crumb falls down through the hopper, it lands into a water wheel that is being turned by a small electric motor. The water for the wheel is being pumped through from a reservoir of water. The waterjet hits both the wheel and the crumb: turning the wheel but also mixing the water and the crumb together. This wheel is placed halfway in a water line which means as the rubber crumb falls off the wheel, it is naturally pulled under the waterline and is pushed onward to the next system automatically, at the same time being cleaned of dust, oil, and contaminants. As the water hits the water wheel it acts as a paddle and pushes the rubber crumb to the next wheel which dunks it once again under the water and then pushes it out the other side. This water wheel is also powered by the electric motor. The crumb gets two applications of water before going on to the next stage. This means that the rubber will now be free of contaminants through this very simple cleaning activity which is highly and massively important and sets the stage for easy processing and efficient processing hereafter.

The crumb must now be dried, as we cannot allow water which may or may not be containing conditioner to go any further than this step. The way that we have simply addressed this is the following: at the end of the water reservoir there is a small conveyor belt made out of loose mesh sieve material to allow water to drain freely back down at the end of that part of the process. The crumb travels along the conveyor and it is then dropped into a rotating drying drum. This has an air pipe that carries the hot air that blows gently over the top of the crumb as it rotates in the drum. At this stage the rubber is now fully dry and is ready to go on to the next stage.

Once the crumb has been dried we need to scarify the surface of the rubber creating micro scratches on the surface so we can coat inoculant, catalysts or additives to the surface efficiently. We achieve this by a simple process in two stages. The first stage goes through a drum which contains scarifying material. In order to create micro cuts in the rubber crumb surface, as the drum rotates the crumb is moved over the surface cutting it as it goes. Once it has passed over the scarifying material the crumb moves down the shaft on to the next part of the process.

Once the crumb is scarified, inoculant or additive must be correctly applied. We chose for this step a very simple process which involves two main stages; the first stage is that it is dropped into a small hopper with a cork screw conveyor or auger and as the material drops into this hopper, the coating material (catalyst/inoculant/additive) is also fed into the auger. The auger or Corkscrew conveyor automatically mixes these materials together for a short distance. The bottom of the auger or Corkscrew conveyor has a sieve bottom which separates any loose inoculants or catalyst or coating material from the bigger particle size of the rubber crumb. Any excess material falls through the bottom of the auger. The rubber crumb goes on to the next stage and the inoculants or catalyst that has fallen through the sieve is then recycled back again to the starting point so nothing is wasted., This 100% ensures the coating material has been applied to the rubber crumb ready for the next stage processing.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a side elevation of an apparatus for cleaning, drying, scarifying and coating rubber crumb - Figure 2 shows a close-up side view of a portion of the inventive apparatus for cleaning the rubber crumb.

Figure 3 shows a close-up side view of a portion of the inventive apparatus for drying and scarifying the cleaned rubber crumb.

Figure 4 shows a close-up side view of a portion of the inventive apparatus for coating the rubber crumb with inoculants or catalysts.

DETAILED DESCRIPTION OF THE INVENTION

As shown in Figure 1, the inventive apparatus consists of several components for cleaning, drying, scarifying and coating the rubber crumb. In a representative embodiment as shown in Figure 1, the apparatus 100 comprises a cleaning portion 101 with water wheels, a drying enclosure 102, a scarifying drum 103 and a coating bin 104. In Figure 2, a close up view of the cleaning portion 201 is provided, showing a bin 202 for holding the rubber crumb and a cleaning solution and also water wheels 203 to provide agitation. Figure 3 provides a close-up view of a drying enclosure 302 and scarifying drum 303. Figure 4 provides a close-up view of a coating bin 404. Representative dimensions are now provided for the various apparatus portions. Dimension sizes are (but not limited to) as bigger and smaller units can be made depending on the throughput you are putting through and the speed of which you wish to process this at.

Step one: cleaning using water, coupled with detergent if necessary:

4.57 metres long one and a half metres wide.

Total height 4 metres.

Step 2: drying: two metres long two metres wide

3 metres high

Step 3 : scarifying micro cutting.

Four metres long by two metres wide by three metres high.

Step 4: coating with the inoculants, additives, or catalysts:

8 metres long two metres wide by two metres high and the catalyst hopper that sits on the top is three and a half metres high

3 metres wide one and a half metres length.

Material choices are made for suitability for the application of processing rubber crumb, optionally particularly waste tyre crumb. One of skill in the art will realise that the materials discussed here are exemplary and that obvious variations can be made.

If materials are to be in contact with water, they must be waterproof and can be made of suitable metal or plastic. Any of the portions that must be open to inspection are made from transparent hardened plastic. Starting with the valve that allows the crumb to fall into the cleaning system onto the water wheel: this is a rotating valve made of metal which allows the material to be dumped into the cleaning chamber in a steady stream. This valve is run by drive motor to building regulation standards.

The water wheel is made from hard wearing plastic. The water reservoir is made from transparent hardened plastic. The trash tube which allows the contaminants to fall through the bottom of the reservoir is see-through hard-wearing plastic and the valve at the bottom of this for removing the contaminants from the tube is made of metal in the form of a lever.

The water piping that takes the water from the reservoir and recirculates it back to the water wheel jet is made from plastic piping used in the water industry and the oil separation tank is also a plastic tank with a metal lever valve. The oil separation tank has two empty chambers for cleaning out the oil from the water tank.

The waterjet nozzle is stainless steel metal (not limited to) and has a screw on the end to increase or decrease volume of water splashing onto the crumb on the water wheel

The air-drying drum is made from stainless steel powder coated steel - the air jet for the top is also metal for longevity purposes

The rubber crumb is heated to help the drying process. The whole unit will heat to approximately 40 to 50 degrees which drives off the water from the rubber. Any appropriate heat source can be used.

The scarify er tumbling machine is made from stainless steel but not limited to, and the scarifying pads are all made from a sandpaper like substance or micro cutting material which is abrasive The catalyst coating part is made from metal but not limited to,

The central auger which carries the material through the system is made from metal with nylon fins on the edges to reduce wear and tear on the bed of which it sits on reducing the friction on the sieve

The sieve is made from metal mesh for durability. Under the sieve is a conveyor belt made from standard conveyor belt material which takes the catalyst and transports it back to the top hopper where catalyst is loaded at the beginning of the further refining process. The hopper is made from either metal or hardened plastic

The valve that opens and closes distributing the catalyst onto the Crumb below is a metal valve. Parameters

The first stage only allows a certain amount of product to fall onto the wheel for cleaning. It will not go any faster than the wheels are turning and is all connected with a belt drive system meaning the faster material drops down would also result in the faster the wheel turning to make sure that everything is synchronised. This can be sped up or slowed down, depending on the amount that you wish to process and the speed of which to workout. Obviously the faster and the more material put in, the more likely it is to miss dust particles throughout the cleaning process and so a stable steady process is recommended.

The water in the reservoir, which is used for cleaning, is visible so operators can see the colour of the water to see if it is necessary for cleaning. A trash tube valve located at the bottom of the machine is made from a transparent material to show the operator when it needs to be emptied as all the heavy contamination will drop down to that bottom part.

It is recommended that every two weeks the water is changed, and the trash tube and trash valve is cleaned and any oil slick is removed. Any oil that has come off the rubber crumb will be collected and any oil separated is collected in a separate small tank. This is located just before the water enters the water wheel as this is easily seen and removed if necessary.

The second stage drawing tumbler will rotate at a steady rate with the air flow from the top hitting the material in the bottom of the tumbler. This will be regulated by a small valve which can regulate the volume of air. This valve can be adjusted depending on the needs at the time. If you have a lot of hot air coming through, you need less air volume and if you have not much hot air and you need more air volume, the drawing tumbler can be speeded up (or down) depending on the volume which is necessary to make sure that the material exiting is 100% dry ready for the next stage.

The third stage scarification depends on how worn the scarifying pads are; these can be unscrewed from the sides of the drum and replaced with new ones if and when necessary. The fourth stage is putting on the inoculant’s catalysts and additives. The turning screw/augur that takes the material throughout the system is on a set flow timing belt which could be adjusted faster or slower if necessary to maximise mixing capacity. This can be increased to hold more volume if necessary by increasing the sides of the catalyst hopper which is situated above the mixing auger and can be adjusted to increase or decrease catalyst flow as a constant trickle feed. The rubber crumb below in the mixing auger moves onto the catalyst separation part of the process where the material is passed over a fine mesh sieve. This sieve can be adjusted and replaced as necessary via screws, unless it can be made bigger or smaller depending on the size of the catalyst, inoculants or additive being introduced. Underneath the surface is a second conveyor belt that captures the loose catalyst or inoculant or additive and takes it back to the top where is recirculated to the holding hopper where the catalyst/ inoculant/ additive is being held. This belt can be slowed or sped up as and when necessary .

Working

Owner of a recycling plant that is processing tyres through a pyrolysis plant and is finding that at the end of their process the carbon black has contamination in it from dust and second hand metals which results in devaluing of their product; in some cases from £700 a tonne down to less than £50 a tonne because of the unclean nature of the material, because this is happening too frequently the plant is now running at a loss resulting in the inevitable closure of a plant. Even though the activity of recycling these products is hugely beneficial to the environment and the employment to the area, it's come to an end because of the unstable price of the materials being sold.

Having one of our processes of cleaning all the contamination off before entering the pyrolysis means there are no contaminants in the material later on giving a stable and reliable product which means that the product is fetching the price point it needs to be. This is a sustainable process and continues the business and keeps employing those workers and saving the environment by reusing products that can go back into manufacturing helping the circular economy.

In another example focused on operating the inventive apparatus, the operator looking after this piece of equipment is doing some maintenance and checking over the machinery. He starts by looking at the valve that allows crumb to fall into the cleaning vessel. He makes sure that enough material is falling through at a steady rate and after that he's watching the crumb falling onto the wheel with the water splashing into the bucket where the crumb is collected in the cleaning process. The operator is checking that the wheels are turning in synchronicity, when he notices that the oil collection point had some oily substance in it. He scoops that out by closing the water valve and opening the valve to the oil extractor which opens into a bucket. This removes the oil before closing the valve again. This does not allow the water to flow back into the oil collector. He resumes his observation after this process, noticing the crumb is flowing through the machine and under the water wheels and onto the next seamlessly. He is happy to see it working in such a fluid manner and checks under the machine where the water reservoir is carefully . He notices that some mud material and metal has gathered at the bottom of the trash tube. He reaches underneath with a bucket, opens the little valve using the lever and the trash falls into the bucket. When the water runs clean again into the bucket, he closes the valve; simply and efficiently removing contamination from the water reservoir. He then disposes of the liquid that he's just collected from the trash tube and he goes to the clean water tap. He fills up the bucket and replaces like for like into the water reservoir to continue cleaning the crumb. Satisfied this is now done, he then moves on to the next section where the crumb is being dried. He notices that the wet crumb is dropping seamlessly into the dryer tumbler. On inspection, he notices that the air coming out of the blower, which normally is warm to dry off the crumb quickly, is running cold. He remembers that they have turned off the equipment which generates the heat in another part of the process so he sensibly increases the volume of cold air time or volume of air is going into the tumbler. Later on he'll come back when there is hot air coming through again and he will close the valve down a bit to reduce the amount of air flow simply quickly and efficiently. Moving on to the scarifying part of the process, the first thing he notices is that some of the scarifying pads have got a little bit blocked. He simply gets out a wire brush holds it against the side as it's turning and removes the sticking rubber. He does this for a couple of moments until satisfied it's all removed, then checking the fin that pushes the rubber against scratching sides. He sees that it is all OK , no adjustment needed and moves on to the next part checking the inoculant is flowing and coating the crumb correctly. Seeing that the crumb is falling into the hopper at a steady rate and a couple of inches later the inoculant /catalyst is being dusted from the top correctly then checking that the rotation of the screw is mixing the two products together smoothly, he is happy with the timing of it. The next part of the process is where any extra catalyst is then sifted out and he notices that some little blotches and blocks have occurred. He gets out his wire brush once again and runs it over, pushing down the catalyst onto the bottom conveyor belt through the mesh which then is returned back to the top hopper of which the catalyst enters where the crumb is being filled. Nothing is lost or wasted and the maintenance operator is happy with the overall success of the process.

Representative embodiments of the inventive apparatus are provided herein. One of skill in the art will understand that variations in materials and dimensions, amongst other things, are possible without departing from the scope of the invention.