Trommel with elongated slots for separating plastics

Abstract

The trommel device has a cylindrical body configured for rotational movement and a plurality of elongated holes or slots formed in the cylindrical body. The trommel device can be used to sort debris from automobile shredder residue.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 432,634, filed December 14, 2023, which is incorporated herein by reference in its entirety.

[0002] The present application relates to a separation device. [Background technology]

[0003] A trommel screen, or rotary screen, is a mechanical device used to separate materials, primarily in the mineral and solid waste processing industries. The device features a perforated cylindrical drum, usually angled at the feed end. Material separation occurs as the feed spirals down the rotating drum, with smaller particles passing through the openings in the screen while larger particles exit at the opposite end.

[0004] Trommel screens, while not typically associated with plastic products, are widely used in municipal waste management to separate solid waste by size. They also enhance fuel recovery from solid waste by removing moisture and inorganic materials such as ash from the air-classified light fraction of shredded solid waste, thereby improving fuel quality. Trommel screens also find use in wastewater treatment, where they facilitate the separation of solids from liquid streams. When the liquid reaches a set level, the screen rotates, and solids accumulate on the screen mesh and are transported for further processing.

[0005] Trommel screens are typically made from perforated plate or mesh. Perforated plate screens, made by rolling and welding, offer strength and fewer ridges, facilitating the cleaning process. Conversely, mesh screens are replaceable and more susceptible to wear and tear, but require more intensive cleaning due to objects getting stuck in the mesh ridges. Screens are typically uniformly shaped or irregularly shaped, which is not conducive to plastic separation.

[0006] Therefore, there is a continuing need for improved trommels. Summary of the Invention

[0007] The present application discloses a trommel device having a cylindrical body configured for rotational movement and a plurality of elongated holes or slots formed in the cylindrical body.

[0008] One aspect is a trommel device having a cylindrical body configured for rotational movement and a plurality of slots or elongated holes formed in the cylindrical body. The slots or slots may be oriented longitudinally along the axis of the cylindrical body. The slots or slots may have a length-to-width ratio of greater than 3:1, greater than 4:1, or greater than 6:1. The slots or slots may be arranged in a spiral pattern along the cylindrical body. The edges of the slots or elongated holes may be reinforced.

[0009] Another aspect includes a method for separating materials using a trommel having elongated slots. The method can include providing a trommel device with a cylindrical body configured for rotational movement and a plurality of elongated holes or slots formed in the cylindrical body, providing a material having plastic to rotate the cylindrical body, introducing the material into the rotating cylindrical body, and allowing smaller materials to exit the cylindrical body through the elongated holes or slots. The material can be plastic or automobile shredder residue. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of one embodiment of a trommel as described herein, featuring a cylinder with an elongated slot. [Figure 2] FIG. 2 is a perspective view of the cylinder shown in FIG. [Figure 3] FIG. 3 is a perspective view of a portion of the cylinder shown in FIG. 2; [Figure 4] FIG. 1 is an explanatory diagram illustrating a method related to the present application. DETAILED DESCRIPTION OF THE INVENTION

[0011] This application describes specific embodiments of a trommel designed for sorting, grading, and separating mixed solids (with substantial plastics) of various sizes in a number of applications. The device can have a rotating drum or cylinder with circumferentially arranged elongated bars or slots. The bars are spaced to allow objects of a desired size to pass through for collection. Essentially, the trommels or trommel devices described herein are cylindrical screening devices primarily used to separate materials containing large amounts of plastics. Incorporating elongated slots into the design of the trommel or trommel device helps improve the efficiency and accuracy of the material separation process.

[0012] FIG. 1 shows a trommel or trommel device (10) consisting of a cylindrical body (20), typically constructed from a durable metal such as steel or aluminum. The cylinder resides within a frame (30). The length and diameter of the cylinder can vary based on intended use and capacity requirements. The surface of the cylindrical body (20) has a screen (50) with elongated slots. These slots are oriented longitudinally, parallel to the trommel's axis (A). The length-to-width ratio of the slots is optimized to help ensure effective sorting of materials while minimizing blockages. The edges of the slots, bars, or screen (50) can be reinforced to resist wear and tear.

[0013] A drive motor (not shown) rotates the cylinder body (20) via a shaft operatively connected to the drum, which may be controlled by an interface or switch (40). The trommel or trommel device (10) is mounted on a horizontal shaft and powered by an external motor. This motor facilitates the rotational movement of the trommel or trommel device, which is essential for the screening process. The rotational speed can be adjusted depending on the material being processed.

[0014] FIG. 2 shows a perspective view of the cylinder body 20 equipped with screens 50. These screens are designed to allow the passage of plastic solids of a specific size based on their mesh spacing. Brushes can be applied to the screens to prevent or reduce mesh clogging and minimize downtime. In certain embodiments, these screens feature elongated slots that allow flat materials of specific dimensions to pass through them.

[0015] In this example, the sorting device, or trommel or trommel device (10), features a drum with elongated slots spaced at various distances (e.g., about 3, 4, 6, 8, 10, 12 inches, or more). These slots are designed to selectively allow flat particles to pass through. The trommel or trommel device (10) retains larger, three-dimensional, or less-flat particles above the screen while sorting out the flatter ones. Despite their larger size, these flat particles are able to pass through the slot due to their minimal thickness compared to the other two dimensions. Trommel-type sorters are designed to utilize centrifugal force or lifters. These mechanisms lift particles and repeatedly drop them onto a slotted screen deck. This repeated reorientation increases the chances that flat particles will align vertically, allowing them to pass through the slot in a flat orientation.

[0016] Figure 3 shows an example of a screen 50 designed to be attached to a cylinder body 20. This illustration highlights how bars 60 are utilized to form slots, each having specific width and length dimensions. Additionally, the screen 50 may include reinforcements 55 for added stability and durability. Slots 70 are shown as spaces between the bars 60.

[0017] 4 illustrates a method 200 for recycling waste materials using a trommel with an elongated slot. The method includes the following steps: first, providing a trommel apparatus featuring an elongated slot (210), second, adding plastic-containing material to the trommel's rotating cylindrical body (220), third, introducing additional material into the rotating cylinder (230), and finally, allowing smaller materials to exit the cylindrical body through the elongated holes or slots (240).

[0018] In its operation and use, a trommel or trommel device can be effective for sorting lightweight materials, particularly plastics. Material is introduced into the upper end of the trommel or trommel device. As it rotates, smaller particles can fall through an elongated slot, thus separating them from larger items. The sorted material is then collected at the lower end of the trommel or via a conveyor located below the slot. Specifically, flexible materials like rubber pass through, while three-dimensional objects like rubber hoses, tire rubber, and wood are filtered out. The incorporation of an elongated slot offers several advantages, including improved sorting accuracy, reduced potential for clogging, and increased throughput. Furthermore, this design is adept at handling a variety of materials, including those that are moist or sticky. An important application of this sorter is separating plastics from waste materials.

[0019] In one embodiment, the present process and system have been found to be highly effective in recovering plastics from waste materials that are aspirated waste, a type of waste common in the European Union from processes that do not involve incineration. Air classifiers are well known in the classification art and result in a light fraction having organic material with limited amounts of metals, which tend to be buried / embedded / entangled in the organic fibers. Often, fibrous materials have plastics buried, embedded, or entangled therein.

[0020] The waste material may have less than 60%, 50%, 40%, 30%, 20%, 10%, 6%, 5%, 4%, 3%, 2%, or 1% plastic by weight or volume. In some examples, the fibrous lightweight material contains more than 95% plastic or organic matter. In some examples, plastic material makes up more than 90% of the waste material after large three-dimensional objects (unshredded material or large objects larger than 5 or 6 mm).

[0021] With respect to waste streams, certain embodiments can be used to process waste materials or recyclable materials containing concentrations of plastic greater than 15%, or 25%, 35%, 45%, and / or 50%. This means that as long as the concentration of plastic is good (as low as 20% or higher), the system can properly sort the material. Household waste pre-sorted into "plastic and non-plastic" streams is a good example. Typically, household waste that is not landfilled can be pre-sorted at a recycling facility where plastic separation occurs. This plastic concentrate is an example of a "good feedstock." Municipal waste containing plastic is an exemplary waste stream material.

[0022] In one embodiment, the feedstock may be automotive shredder residue (ASR). Automotive shredder residue (ASR) typically comprises 15-25% of a vehicle's mass at its end-of-life stage (after it has become an end-of-life vehicle or ELV) and is the residual material remaining after processes such as decontamination, dismantling, shredding, and metal extraction. ASR can be divided into three categories: "light fluff," "heavy fluff," and mineral fractions. Both light fluff and heavy fluff are distinguished by their high concentrations of combustible materials, including plastics, rubber, and textiles.

[0023] 1 and 2 show an exemplary trommel sorter featuring a slot with bars extending along the length of the trommel supported by a circumferential ring. The slot width in various embodiments may range from ¼ inch to 1 inch, or any increment within this range. The slot length varies between 3 inches and 24 inches, with increment options within this range. These dimensions are carefully selected to optimize plastic recovery from the waste stream. In some designs, the longer dimension of the slot is 2 to 8 times larger than the size of the plastic pieces being sorted. In one example, the longer dimension can be 2 to 8, 3, 4, 5, 6, 7, or 8 times the size of the plastic droplets.

[0024] Different elements or parts of the module are constructed using different construction materials such as stainless steel, mild steel, etc.

[0025] As will be appreciated, the trommel or trommel device can be optimized in a variety of ways. For example, the size of the elongated slot can be adjusted to fit a particular material size. Additional features, such as brushes or scrapers, can be added to keep the slot clean. Furthermore, the trommel or trommel device can be designed to be portable or stationary, depending on the application.

[0026] Although specific embodiments of the present disclosure have been described in detail above, the description is for illustrative purposes only. It should be understood that the description illustrates aspects of the present invention that are relevant to a clear understanding of the invention. Certain aspects of the present invention that would be apparent to those skilled in the art and that therefore do not facilitate a better understanding of the invention have not been presented in order to simplify the description. Having described embodiments of the present invention, those skilled in the art will recognize that many modifications and variations of the present invention can be employed in light of the foregoing description. All such modifications and variations of the present invention are intended to be covered by the foregoing description.

Claims

1. 1. A trommel device, comprising: a. a cylindrical body configured for rotational movement; b) a plurality of elongated holes or slots formed in said cylindrical body.

2. The trommel device wherein the elongated holes or slots are oriented longitudinally along the axis of the cylindrical body.

3. 2. The trommel apparatus of claim 1, wherein the slots have a length to width ratio of greater than 3:

1.

4. 2. The trommel apparatus of claim 1, wherein the slots have a length to width ratio of greater than 4:

1.

5. 2. The trommel apparatus of claim 1, wherein the slots have a length to width ratio of greater than 6:

1.

6. The trommel apparatus of claim 1 , wherein the elongated holes or slots are arranged in a spiral pattern along the cylindrical body.

7. 2. The trommel apparatus of claim 1, wherein the edges of the slots are reinforced.

8. 2. The trommel apparatus of claim 1, wherein the slot is at least 0.75 inches in diameter.

9. 1. A method of separating materials using a trommel having an elongated slot, comprising: Providing a trommel device according to any one of claims 1 and providing a material comprising plastic to rotate the cylindrical body; introducing a material into a rotating cylindrical body; and allowing smaller materials to exit said cylindrical body through said elongated holes or slots.

10. The method of claim 9 , wherein the material comprises a plastic.

11. 10. The method of claim 9, wherein the waste material is automobile shredder residue.

Images