Additives can be added during the cryogenic grinding process. Typical products All components. We have developed a proprietary cryogenic freezing system, utilizing the most efficient use of This system allows for two different fine grind systems, depending on the
A process for recovering crumb rubber from used vehicle tires wherein Cryogenic grinding crumb rubber methods tires are comminuted in three comminuting operations, the second and third of which are jethods by contact with a liquid cryogenic. Thus, the degree of purity of the crumb rubber mesh product is very high, meeting all requirements imposed by users of crumb rubber in terms of allowable concentrations of foreign materials such as fibers and ferrous metals. An apparatus in accordance with claim 27 wherein said cryogenic liquid is liquid nitrogen and wherein said cryogenic cooling tunnel includes gaseous nitrogen outlet means for removal of said gaseous nitrogen product of said liquid nitrogen contact with said rubber particles. Jul Fuck nude milf, This metal is sold. A process in accordance with claim 6 including a second sorting step, prior to step aof removing tires not processable in the Cryogenic grinding crumb rubber methods of crumb rubber. Second cryogenic liquid contacting step 7, in a preferred embodiment, is substantially identical to first cryogenic liquid contacting step 3. Moreover, it utilizes the same cryogenic recycle scheme discussed above and depicted in FIG. The fiber is removed by aspiration and screening. More recently, processes which recover the grunding constituent of vehicle tires, for reuse in the manufacture of rubber-containing articles, have been developed.
Arlene farmer secure web search sex. Crumb Rubber Information
This investigation resulted in a method to quantify Cryogwnic the interaction effect IE and particle effect PE of CRM, which contribute to the increased rheological properties of CRM binders. CryogeniC versus Ambient rubber turf talk vol. These effects were determined using a rotational viscometer and a dynamic shear rheometer DSR to measure the rheological properties of CRM Cryogenic grinding crumb rubber methods produced CCryogenic three sizes of CRM, two crumb rubber processing methods ambient and cryogenic grindingtwo CRM contents, and three binder sources. Get a quote. Cryogenic grinding crumb rubber methods Of Cryogenic Grinding Machine, process crusher, mining Industrial Rubber - Midwest Elastomers. An additional benefit of cryogenic milling in an internally agitated ball mill is the ability to fully immerse the product in liquid nitrogen during milling. Rubber powder is used as basis material for new products and. PutmanSerji N. Carbon grinding plant. Silica sand processing rjbber. Get A Free Quote.
Crumb rubber is the name given to any material derived by reducing scrap tires or other rubber into uniform granules with the inherent reinforcing materials such as steel and fiber removed along with any other type of inert contaminants such as dust, glass, or rock.
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Additives can be added during the cryogenic grinding process. Typical products All components. We have developed a proprietary cryogenic freezing system, utilizing the most efficient use of This system allows for two different fine grind systems, depending on the We can add value-added technology so that all of the rubber crumb In case of cryogenic grinding, one phase normally suffices for reaching the Cryogenic grinding installations are used for: Polyester.
Synthetic rubber. Heat sensitive polymers. Composite materials. The cryogenic method of freezing the rubber below its embrittlement point followed by There are several processes for manufacturing crumb rubber.
Two of the most common are ambient grinding and cryogenic processing. A third technology-the For decades, rubber and plastics processors have relied on Air Products' industry experience, technologies, and technical know-how to help improve their Reclaim made from inner tubes for tyres, made of butyl rubber, is an For samples that are soft or flexible at room temperature, cryogenic grinding The embrittlement of the sample makes even elastic and soft samples grindable.
Keywords: cryogenic grinding; lN2-consumption; cooling of granulate materials; alternative technology; Jul 8, Cryogenic grinding is a method of powdering products For commercial scale grinding of scrap tire peels in a cryogenic state, it is. Cryogenically-ground rubber has a fine particle size, varying from 30 to mesh.
Except for Grinding processes for tire rubber are well developed. They are Global Technical function: Manufacturing, Grinding The new grinding device is more effective than mechanical mills such as the ACM pulverizer. The cryogenic grinding results also show that rubber products of The Pulva Corporation provides services for high speed grinding machines, cryogenic grinders, and crushing and grinding services.
The feeder is suitable for precooling a wide variety of materials, including plastic, rubber, food and drugs to Plastic, elastic, and heat-sensitive materials have properties that make fine Applications for cryogenic grinding include rubber, plastic, metal, composites, Cryogenic recycling and processing.
Norman R. Companies that provide cryogenic grinding of materials such as used tires and other rubber components, plastic, drugs and foods, including spices. The Cryogenic Treatment Database is a leading resource for research and information in Activated carbons were obtained from the cryogenic grinding of used tyres using Jun 22, There are two major technologies for producing crumb rubber — ambient mechanical grinding and cryogenic grinding.
Of the two processes, The lower practical limit for the. The main advantage of cryogenically frozen rubber is that it pulverises Cryogenic grinding is widely used for the reduction in size of particles. Grinding of Rubber Material. Sep 14, Crumb Rubber Shredder Machine - New and innovative dry ambient system! How can we account for what is perhaps one of the most spectacular waste disposal failures in No possibility for surface oxidation, due to the nitrogen grinding medium.
RTI Cryogenics - The System We have developed a proprietary cryogenic freezing system, utilizing the most efficient use of Cryogenic Grinding Cryogenic grinding installations are used for: Polyester. Development and application of superfine tire powders for rubber Rubber and Plastics: Air Products' Gas-based Solutions For decades, rubber and plastics processors have relied on Air Products' industry experience, technologies, and technical know-how to help improve their Environment - Recycled rubber Reclaim made from inner tubes for tyres, made of butyl rubber, is an Cryogenic grinding - Wikipedia, the free encyclopedia For samples that are soft or flexible at room temperature, cryogenic grinding Optimised technologies for cryogenic grinding Keywords: cryogenic grinding; lN2-consumption; cooling of granulate materials; alternative technology; Freezing for Fineness Jul 8, Original paper A novel cryogenic grinding system for recycling scrap Evaluation of Waste Tire Devulcanization Technologies - CalRecycle Cryogenically-ground rubber has a fine particle size, varying from 30 to mesh.
A novel cryogenic grinding system for recycling scrap tire peels The new grinding device is more effective than mechanical mills such as the ACM pulverizer. Cryogenic Grinding. Fine-Particle Pulverization with Cryogenic Recycling of Solid Trash Breaking up of waste Cryogenic Grinding Services in the CSA Buyer's Guide Companies that provide cryogenic grinding of materials such as used tires and other rubber components, plastic, drugs and foods, including spices.
Characterization, Analysis and Comparison of Activated Cryogenic grinding: an independent voice - thiswritingbusiness cryogenics. Cryogenic separation - Wikiversity Jun 22, Biotechnological Processes for Recycling of Rubber
Powered by:. This can then. Cryogenic milling machines Scrap tyre recycling Waste Management World. Cryogenic grinding refers to the grinding of scrap tyres at temperatures near minus 80 o C using liquid nitrogen or commercial refrigerants.
Cryogenic grinding crumb rubber methods. Recent Products
The present invention is directed to a process and apparatus for making crumb rubber from used automobile and truck vehicle tires. More particularly, the present invention is directed to a process and an apparatus of making vehicle tires which involves multiple cryogenic cooling of comminuted rubber particles wherein the cryogenic fluid is recycled. The daunting number of used tires that must be disposed of annually has not only filled waste disposal sites but, unfortunately, has additionally resulted in indiscriminate discarding of tires creating a major environmental problem.
It is for this reason that a great number of processes have been advanced for the disposal of tires in a manner that not only eliminates them as an environmental problem but provides a product that recovers some or all of the cost of such tire disposal.
In one type of disposal scheme a whole plurality of processes have been developed in which used tires are comminuted and the fuel value inherent in the significant volatile content of vehicle tires is recovered. More recently, processes which recover the rubber constituent of vehicle tires, for reuse in the manufacture of rubber-containing articles, have been developed.
Of particular interest are rubber recovery processes which involve the utilization of cryogenic fluids, usually very cold liquid and gaseous nitrogen, to permit the comminution of the tires into small solid particles without attendant melting or significant softening of the rubber.
Although the advance provided by cryogenic cooling of vehicle tires and rubber particles thereof advances the art insofar as it greatly increases the efficiency of the comminuting process, such processes are plagued by two major problems. The first such problem resides in the high cost of utilizing cryogenic fluids. Most of the processes that have been developed utilize fresh sources of cryogenic fluids which, after their employment in cooling and embrittling rubber, are vented to the atmosphere.
This venting represents a complete surrender of that charge of the high cost cryogenic fluid. A second related problem associated with prior art processes is the inability to produce fine sized rubber particles suitable for reuse in the manufacture of rubber articles. Those skilled in the art are aware that very finely divided rubber particles are essential if the crumb rubber product of tire comminution processes can be sold to rubber and rubber application manufacturers.
This, in turn, may be the result of the absence of processes that cryogenically treat small enough particles so that they can be further comminuted to the requisite size required for commercial resale.
Obviously, this absense may be the result of the expense associated of more than one cryogenic fluid contacting steps. The above remarks can be better appreciated by reference to illustrative prior art processes which not only set forth the current state of the art but also emphasize their limitations. In this process tires are shredded into smaller particles which are cooled by contact with a cryogenic gas.
Indeed, the process of the ' patent involves two cooling steps prior to first particlizing tire portions and thereafter comminuting rubber granules. That process also involves recycling the cryogenic cooling gas employed in the two cooling steps for reuse.
A problem associated with the process of the ' patent is that the cooling gas used in this process cannot provide the degree of cooling necessary to permit the degree of comminution required to produce the fine sized particles essential for production of crumb rubber. In this absence the cost of removing tires from the environment cannot be recouped.
A second disclosure which provides a process and an apparatus for reducing rubber to particles is not particularly directed to the conversion of tires into crumb rubber.
Rather, the process of this prior art reference concerns the comminution of scrap rubber, rather than whole tires, into fine sized rubber.
It is true, of course, that the scrap rubber may be product of shredded vehicle tires. Be that as it may, U. That is, the vapors emanating from a downstream cryogenic liquid are directed, by means of a conduit, upwardly by gravity to a precooling chamber.
The precooled product of the upwardly moving precooling chamber is thereupon passed through a bath of a cryogenic liquid. Although the process of the ' patent avails itself of the vapor from a separately used cryogenic liquid that gas is ultimately vented. Furthermore, the first cooling step does not take particular advantage of the fact that there are two cryogenic fluid contacting cooling steps in that both cooling steps are associated with only one comminution step.
The cryogenic gas precooling steps merely enhances the efficiency of the single cryogenic liquid contacting step. The above illustrations of the prior art emphasize the need in the art for a process and an apparatus that combines a sufficient number of comminution steps preceded by cryogenic liquid cooling to ensure the formation of fine crumb rubber in a manner that insures that the costs and expenses associated conducting these cryogenic cooling steps does not make this process economically infeasible.
A process and an apparatus has now been developed which provides adequate comminuting steps preceded by efficient cryogenic cooling such that crumb rubber of a size that can be utilized in rubber forming operations, and is thus commercially useful, is provided.
At the same time, this process and apparatus minimizes the use of cryogenic fluids required to provide these efficient comminution operations. This is accomplished by novel cryogenic fluid recycle operations, consistent with the efficient contact of rubber particles prior to subsequent comminution, with a cryogenic liquid. In accordance with the present invention a process for producing crumb rubber from vehicle tires is provided.
In this process used vehicle tires are shredded to provide rubber particles which include embedded metal and fiber. These rubber particles are thereupon contacted with a cryogenic liquid. The thus cooled rubber particles are reduced in size and substantially all the metal and fiber embedded therein are removed. The substantially pure rubber particles are thereupon again contacted with a cryogenic liquid followed by reduction in particle size to produce the crumb rubber product.
In further accordance with the present invention an apparatus for producing crumb rubber from vehicle tires is set forth. A first cryogenic liquid contacting means cryogenically cools said rubber particles.
A second comminuting means reduces the average particle size of the rubber particles cooled in the first cryogenic luqid contacting means. A second cryogenic liquid contacting means again cools the rubber particles which are substantially fiber- and ferrous metal-free.
A third comminution means further reduces the average particle size of the rubber particles. Screening means are provided to separate the rubber particles which pass through the desired particle size screen required of crumb rubber.
The present invention will be better understood with reference to the accompanying drawings of which:. The process and apparatus of present invention begins with the introduction of a supply of used vehicle tires which may be automobile, truck or off the road tires.
These tires are initially segregated to remove those tires which can be reused. That is, those tires that can be recapped, retreaded or reused are segregated for resale and reuse. This, of course, represents the most efficient use of the tire insofar as it not only permits reuse, creating an asset from an otherwise environmental liability, but it also provides the highest revenue based on its cost to the processor since it also eliminates processing of those tires in the process and apparatus of the present invention.
The remaining tires are further sorted to separate those tires that are not suitable for processing in the process and apparatus of making crumb rubber. Tires that are oxidized, heavily contaminated or merely whitewalled are unsuitable for crumb rubber production in the process and apparatus of the present invention. These unacceptable tires are shredded to provide approximately one inch particles. It is emphasized that the nominal size reported above and hereinafter refers to the maximum length of the particle in any direction.
Thus, the term "one inch particles" represents a particle which has a one inch diameter spherical shape, a one inch cubic shape or any geometric shape therebetween wherein the maximum dimension is approximately 1 inch. They are thereupon sold to industries wherein cheap sources of fuel are employed. Thus, such industries as, for example, the paper and pulp industry and the electric power industry which utilize furnaces that have the capability of burning almost any combustible material represent ready markets for this product.
Those tires which have not been selected for reuse, recapping or retreading but have been found suitable for processing to form crumb rubber represent the raw material of the crumb rubber process of the present invention. Even this group of vehicle tires, however, is subject to sorting and selective processing. Therefore, off the road tires, which are very large and heavy tires, are segregated from truck and automobile tires. The off the road large size tires are debeaded and cut into manageable size by special heavy cutting apparatus such as a hydraulic shear.
A large size cutting apparatus such as a basic scissor type hydraulic shear is required to cut these oversized and heavy tires into manageable pieces that can be handled by the comminuting apparatus used to shred automobile and truck tires. These thus cut off the road tires are subjected to the first comminuting step in accordance with the processing of the below discussed automobile and truck tires. The remaining non-off the road tires suitable for processing in the crumb rubber process of this invention are sorted again to segregate automobile tires from truck tires.
The larger and heavier truck tires are separated from the smaller and lighter automobile tires in order to more efficiently comminute them. Although both type of tires are subject to the same type of comminution process, in the same apparatus, the conditions under which the two processes take place varies in accordance with the above characteristics of the two types of tires. However, although the same equipment may be used in this initial comminution step, the first comminuting means is usually provided with varying cutting speeds.
Automobile tires, being lighter, are subjected to faster shredding while truck and off the road tires, being heavier, are subjected to slower cutting speeds.
The approximately 1 inch rubber particles, in a preferred embodiment, are subject to a ferrous metal removal step in ferrous metal removal means to remove loose ferrous metal particles that are not firmly embedded in the approximately 1 inch rubber particles product of the first connimuting step.
The about 1 inch rubber particles are thereupon contacted with a cryogenic liquid in a first cryogenic liquid contacting means. The cryogenic liquid embrittles the particles such that they can easily be reduced in size by any of many rubber comminution reduction methods known in the art using well known comminution means.
The chilling of the rubber particles insure that the particles, during size reduction, remain in the solid state; that the apparatus used to reduce particle size does not plug or reduce speed because of the formation of semi-molten or even highly viscous liquids; and that the wear and tear of the apparatus employed to reduce the size of the particles is minimized. It is emphasized that the process and apparatus of the present invention involves direct contact between a cryogenic liquid and solid rubber particles.
This method is more effective than cooling between solid rubber particles and a cryogenic gas. This is so in that conductive heat transfer efficiency resulting from direct contact between a cryogenic liquid and solid rubber particles is far more efficient than is the convective heat transfer between a cryogenic gas and solid rubber particles. Any of the well known comminuting means utilized as the second comminuting means to reduce rubber particle size may be utilized in this step.
Thus, such apparatus as a grinder mill, an impact grinder, a hammer mill, a ball mill or the like may be utilized to effect this second comminution processing step.
Thus, these materials are separable at this stage in the process. It is mentioned in passing that the separation of these two separate materials is not only essential in order to provide commercially viable crumb rubber, free of these materials, but these materials have a market of their own, albeit at a much lower price than that obtained for crumb rubber.
Indeed, the necessary separation of these components are partially compensated for by the marketing of these products. Fibers, which, as stated above, are often times present in vehicle tires, are substantially separated from the rubber particles in the second comminuting step, are removed by methods well known in the art.
Preferably, this involves air classification wherein the fibers, having a lower density than the other solid comminution products, are separated therefrom, as will be discussed below. Ferrous metal is also physically separated from the rubber particles in the second comminution step. This ferrous metal component is thereupon removed in a ferrous metal removal step by ferrous metal removal means.
This removal is preferably accomplished by magnetic attraction of the metal from the rubber as in many processes of the prior art. This second cryogenic liquid cooling step, employing second cryogenic liquid contacting means, is employed in order to again comminute the rubber particles to reduce their size directly to the particle size at which crumb rubber is commercially traded. It is important to appreciate that the comminution of rubber particles to a size sufficient to pass through a mesh screen is not well known in the prior art.
That is, the prior art processes of producing crumb rubber from vehicle tires produces only small concentrations of mesh particles and thus requires a much greater vehicle tire throughput to attain commercially viable product yields.
Thus, grinder mills, impact grinders, hammer mills, ball mills and the like are usually utilized in effecting this comminution. The product of this step is preferably screened to insure that only particles having a size passing through a mesh screen are recovered. That is, these oversized rubber particles are subject to ferrous metal particle removal followed by treatment again in the second cryogenic liquid contacting means. In a preferred embodiment, to insure adequate separation of ferrous metal particles, which oftentimes are present in very small size, the mesh crumb rubber product is again subjected to metal separation.
It is emphasized that the above discussion does not describe in detail a novel aspect of the process and apparatus of this invention, the cryogenic liquid contacting steps.
These contacting steps represent a major advance in this art. This processing will be discussed below in detail. Suffice it to say, it permits recycling of the cryogenic fluids which, in the prior art, added significantly to the cost of processes for converting vehicle tires into crumb rubber.
To better appreciate the process of the present invention, attention is directed to FIG. The process and apparatus begins with sorted tires, depicted at 1. These tires, as discussed below, are those that remain after removal of the reusable, retreadable or recappable tires present in any shipment of tires provided for processing in accordance with the process of the present invention.