Lightweight plastic densification equipment

Abstract

Generally, the present disclosure relates to an apparatus that compresses lightweight plastic waste (e.g., used grocery bags, empty trash bags, food wrappers, etc.) and then applies a limited amount of heat to "bake" the compressed plastic into plastic "bricks." The plastic is compressed and then heated sufficiently to retain its compressed shape without melting or substantial outgassing.

Description

Technical Field

[0001] This application claims the priority of U.S. Patent Application No. 17 / 119,469, filed on December 11, 2020, the entire content of which is incorporated herein by reference.

[0002] This disclosure relates to increasing the density of plastic materials and further to preparing materials for recycling. In general, this disclosure relates to converting non-recyclable lightweight (low-density) plastic waste into a recyclable form.

Background Art

[0003] Plastic waste can be a pollutant that is difficult to store and transport over a long period of time. Plastics have many good structural properties. It is lightweight, strong, and has a low manufacturing cost. As a result, lightweight plastics have become part of the daily lives of many people around the world.

Summary of the Invention

[0004] This disclosure includes systems, methods, and apparatuses for increasing the density of plastics, such as household plastic waste. One embodiment includes a plastic densification apparatus including a body that partially surrounds an internal volume with an aluminum inner surface. A loading port in the body allows plastic to be loaded into the body, and a lift in the body can reduce the internal volume and compress the plastic within the internal volume when operating. A heating element disposed in contact under the aluminum surface can be configured to heat the plastic within the body to a temperature in the range of 100°C to 180°C.

[0005] Embodiments can optionally include one or more of the following features:

[0006] In some embodiments, the plastic densification apparatus includes a loading mechanism attached to a loading port, the loading mechanism including a roller having a friction surface configured to grip the plastic and pull the plastic into the body, a comb mounted on the roller and configured to remove the plastic from the roller and deposit it through the loading port, and a roller motor configured to rotate the roller. The plastic densification apparatus may also include a controller to control the operation of the plastic densification apparatus and a lift motor to actuate a lift.

[0007] In some embodiments, the plastic densification apparatus includes one or more temperature sensors and one or more current sensors that measure the current supplied to a lift motor. In some embodiments, the controller adjusts the power supplied to the heating element to maintain the temperature sensed by the temperature sensors within the range of 100°C to 180°C. The controller may also be configured to apply current to the lift motor up to a predetermined threshold. The predetermined threshold may be a current related to a desired amount of compression of the plastic.

[0008] In some embodiments, a viewing window is provided inside the main body to allow inspection of the internal volume and plastic material.

[0009] In some embodiments, the cover is hinged to the main body.

[0010] Generally, this disclosure envisions a method for densifying plastics, the method comprising loading the plastic to be densified into a compression chamber, compressing the plastic, applying heat to the plastic to achieve a temperature in the range of 100°C to 180°C, and baking the compressed plastic into a brick-like form.

[0011] In some embodiments, the plastic is periodically compressed during the loading process without the application of heat.

[0012] In some embodiments, heat is applied to the plastic in response to a signal that the compression chamber is full.

[0013] In some embodiments, a loading mechanism is used to load plastic into a compression chamber, which is automatically activated in response to a signal indicating the presence of plastic within the loading mechanism.

[0014] In some embodiments, the steps of compressing the plastic and applying heat to the plastic are repeated at least once. In some embodiments, the steps of compressing the plastic and applying heat are repeated in response to an instruction that a predetermined compression ratio has not been achieved.

[0015] In some embodiments, the steps of compressing the plastic and applying heat to the plastic are repeated a predetermined number of times.

[0016] Details of these and other forms and embodiments of the Disclosure are described in the accompanying drawings and the following description. Other features, purposes and advantages of the Disclosure will become apparent from the specification, drawings and claims. [Brief explanation of the drawing]

[0017] [Figure 1] This is an isometric view of an exemplary plastic densification apparatus.

[0018] [Figure 2] This is a cross-sectional perspective view showing the inside of a plastic densification device.

[0019] [Figure 3] A rotational diagram shows an exemplary plastic densification device, with some housing components made transparent for clarity.

[0020] [Figure 4] This shows a plastic densification device with its cover open.

[0021] [Figure 5] Shows a side cross-sectional perspective view of the plastic densification device 100.

[0022] [Figure 6] It is a block diagram showing a controller 628 and several sensors and systems with which the controller can operate.

Mode for Carrying Out the Invention

[0023] In general, the present disclosure relates to an apparatus and a method of use for densifying plastic waste. The densified plastic waste is a more compact solid than in its non-densified form. Lightweight plastic waste (e.g., used food bags, empty garbage bags, food wrapping paper, etc.) can be difficult to process for storage, transportation, and recycling. The present disclosure describes a convenient solution that enables a user to compress or densify plastic waste within the home, making it easily recyclable, more conveniently storable, or easily transportable for further processing.

[0024] This apparatus compresses plastic waste and then applies a limited amount of heat to "bake" the compressed plastic into a "brick" shape of plastic. Most plastic materials begin to release volatile organic compounds (VOCs) when they exceed a certain temperature. VOCs are generally toxic and undesirable in a residential environment, and thus the disclosed apparatus does not raise the temperature of the plastic so high as to cause significant gas evolution of the plastic by melting it over a wide range. Instead, the plastic is compressed and then heated sufficiently to retain its compressed shape without melting or substantial gas evolution. [[ID=[]] [[ID=[]]

[0025] [[ID=[]] FIG. 1 is an isometric view of the exterior of the plastic densification device 100. The plastic densification device 100 can include a main body 102 that houses most of the components, and can provide an aesthetically pleasing structure for the plastic densification device 100. In some embodiments, the main body 102 is made of plastic, aluminum, steel, or any other suitable material. The cover 106 can be hingedly connected to the main body and can be opened to allow for the removal of densified plastic or the maintenance of the plastic densification device 100. In some implementation forms, the cover 108 is attached to the main body 102 in a slot-like manner (e.g., via a tongue and groove system) or is simply placed on top of the main body 102, but the present disclosure is not limited thereto. The cover 106 will be described in more detail below with reference to FIG. 4.

[0026] In some embodiments, the plastic densification device 100 includes a loader 104 or a loading mechanism. The loader 104 can be attached to the cover 106 or the main body 102 and can assist in feeding lightweight plastic waste into the main body 102. In some embodiments, the loader 104 includes active power components that will be described in more detail below with reference to FIGS. 2 and 3.

[0027] FIG. 2 is a cross-sectional perspective view showing the internal portion of the plastic densification device 100 and some additional components. The main body 102 includes an inner wall 208 that can be made of an aluminum material. Aluminum is a good heat conductor, which is advantageous because heated plastic does not adhere to it. In some embodiments, the inner wall 208 is made of steel or another suitable material that has good thermal conductivity, sufficient structural integrity, and does not adhere to heated plastic.

[0028] The heating element 210 can be positioned between the inner wall 208 and the outer wall of the body 102 so as to surround a portion of the internal volume of the body 102. The heating element 210 may include resistance heating components such as nichrome 80 / 20 (80% nickel, 20% chromium) strips, silicon carbide, or other elements that can convert electricity into heat. The heating element 210 is positioned to apply heat to the compressed plastic within the body 102 of the plastic densification apparatus 100. In some embodiments, heating elements 210 are located within each wall of the body 102 (e.g., four walls), the cover 106, and the lift 212 to apply heat to the plastic from all directions.

[0029] The lift 212 is a mechanism configured to reduce the volume of the containment space within the main body 102 and compress the plastic inside. The lift 212 is shown in a scissor-lift configuration having a flat plate supported by a number of crosslinks. In some embodiments, the lift 212 may have an aluminum upper surface having a heating element 210 configured to apply heat to the bottom of the plastic being compressed. The lift 212 can be actuated by any suitable means. In some embodiments, a hydraulic or electric motor can rotate a screw drive that changes the distance between the two links of the scissor lift at the lower end. An exemplary lift motor is illustrated and will be described in more detail below with respect to Figure 3.

[0030] The loader 104 in Figure 2 is shown with a portion of its external housing removed, revealing rollers 214, bevel gears 216, and combs 218. Note that one roller 214 has been removed from the figure for clarity. The rollers 214 may include a number of bumps or knobs capable of gripping lightweight plastic for feeding into the body 102. The rollers 214 can be made of rubber, plastic, metal, or a combination thereof, suitable for providing traction to pull the plastic into the plastic densification device 100. As shown, the rollers 214 may have a generally spherical shape. In some embodiments, they may be cylindrical or helical, among other shapes. The rollers 214 may be driven by a motor (not shown) capable of rotating all of the rollers 214 via the bevel gears 216. While there are three spherical rollers 214 in the illustrated example, more or fewer rollers 214 (e.g., six or two) can be implemented without departing from the scope of this disclosure.

[0031] Figure 3 is a rotational view of an exemplary plastic densification apparatus 100, with some housing components made transparent for clarity. The lift 212 is shown in the extended position, as in the case of compressing plastic. In the illustrated embodiment, the lift 212 is actuated by a lift motor 320, which may be an electric motor (e.g., a brushless DC motor, a stepping motor, an AC motor, etc.) that translates a crossbeam 324 and drives a screw drive that extends or retracts the scissor mechanism of the lift 212 based on the rotational direction of the lift motor 320.

[0032] The loader motor 318, also shown in Figure 3, can be a single electric motor similar to or different from the lift motor 320. In the illustrated embodiment, the loader motor 318 drives three rollers 214 via multiple sets of bevel gears 216.

[0033] A viewing window 322 can optionally be installed on the main body 102 and can provide a means for the user to visually inspect the plastic inside the plastic densification device 100. The viewing window 322 can be made of plexiglass, glass, quartz, or other suitable transparent material (e.g., Pyrex®). As shown in the illustrated example, two viewing windows 322 can be installed, which are vertical windows that show the amount of plastic inside the main body 102 and the position of the lift 212. In addition to the vertical windows, a larger window can be provided at the bottom to allow inspection of the densified plastic. In some embodiments, the lower window 322 can be left open for easy removal of the densified plastic.

[0034] Figure 4 shows a plastic densification apparatus with the cover 106 in the open position. The open cover 106 can provide access to a storage volume 424 located within the main body 102 of the plastic densification apparatus 100. The storage volume 424 can be a region where plastic is stored, compressed, and heated for densification. In some embodiments, the open cover 106 allows for easy removal of the densified plastic from the storage volume 424.

[0035] Figures 5A and 5B show lateral cross-sectional views of the plastic densification apparatus 100. The areas in Figures 5A and 5B with cross-hash patterns indicate the areas of the plastic densification apparatus 100 that have heating elements for applying heat to the plastic. Generally, the operation of the plastic densification apparatus 100 can be divided into two stages: a loading stage and a densification stage.

[0036] During the loading phase, the lift 212 may be maintained near the bottom of the plastic densification device 100, as shown in Figure 5A. The plastic to be densified is loaded via the loader 104. In some embodiments, the loader includes one or more sensors that activate automatically when the presence of the plastic to be loaded is detected. Generally, the loading phase can be a long-term phase. For example, the plastic densification device 100 can be in the loading phase whenever it is not full and may be slowly filled with the plastic to be densified (e.g., grocery bags, wrapping paper, packaging materials, etc.) over a predetermined period (e.g., once a week, once a month, etc.). Once the plastic densification device 100 is full, the densification phase can be started. In some embodiments, the plastic densification device 100 automatically detects when it is full and starts densification. In some embodiments, densification is started based on user input (e.g., the user presses a “compress” or “densify” button).

[0037] During the densification phase, the lift 212 rises, compressing the lightweight plastic to a smaller volume including the heating area 526. In some embodiments, a predetermined amount of pressure is applied by the lift 212. For example, the amount of torque, and therefore the amount of pressure, can be determined by measuring the current supplied to the electric motor that operates the lift 212. In some embodiments, additional sensors (e.g., force sensors or pressure sensors) can be used to determine the height to which the lift 212 is raised. Once the plastic is compressed, the heating element can apply heat to "bake" the plastic, hardening it and causing it to retain its compressed shape without significant melting or gas release. The heat applied maintains the plastic in the range of 100°C to 180°C, preferably below 120°C. The upper limit of 180°C prevents significant gas release and the release of toxic VOCs from the plastic. The lower limit of 100°C ensures that any moisture present in the plastic vaporizes and escapes from the densified plastic. In some embodiments, once the plastic enters a desired temperature range, the lift is further activated to apply additional pressure to further compress the plastic. This may be a periodic, iterative process of applying heat and pressure. In some embodiments, this process is performed a predetermined number of times (e.g., three or five times). In some embodiments, the process may be performed until a predetermined criterion (e.g., compression ratio or target volume) is met. For example, this process may be repeated until a compression ratio of less than 5% is achieved. Following densification, the heating element is de-energized, allowing the densified plastic to return to ambient temperature. The lift 212 can be retracted to allow more plastic to be deposited on top of the densified plastic bricks or to maintain its position, allowing for easy removal of the bricks. In some embodiments, when a cover or outlet in the plastic densification device 100 is opened, the lift 212 can raise the bricks, partially removing them from the densification device 100 for easy removal.

[0038] Figure 6 is a block diagram showing the controller 628 and several sensors and systems on which the controller can operate. The plastic densification apparatus 100 can be coupled to the controller 628 in a communicative manner. Although shown as separate components in Figure 6, the controller 628 or a part of the controller 628 can be integrated into the plastic densification apparatus 100.

[0039] The controller 628 can receive inputs 630 from various sensors within the plastic densification apparatus 100. These inputs may include temperature signals from one or more temperature sensors 634. The temperature sensors 634 may be thermocouples, resistance temperature detectors (RTDs), thermistors, or other suitable temperature sensors. The temperature sensors 634 may be located within the plastic densification apparatus or near the heating element 650, which may be similar to or different from the heating element 210 described with reference to Figure 2. The temperature sensors 634 can provide signals indicating the temperature of the heating element 650, the internal temperature of the plastic densification apparatus 100, the measured or estimated temperature of the plastic within the plastic densification apparatus 100, or any combination thereof. The controller 628 can also receive inputs 630 from one or more current sensors 636, which can provide an indication of the current supplied to various components within the plastic densification apparatus 100 (e.g., compressor motor 642, loader motor 644, heating element 650, etc.). One or more position sensors 638 can also provide input 630 to the controller. The position sensors 638 may be, for example, encoders connected to actuators associated with a loader or lift (e.g., lift 212 and loader 104 as described in relation to Figure 2). In some embodiments, the position sensors 638 may be Hall effect sensors or arrays of Hall effect sensors that sense a magnetic field and can determine the position of various components of the plastic densification apparatus 100 (e.g., lift 212, cover 106, etc.).

[0040] One or more presence detectors 640 can sense the presence of plastic in the plastic densification device 100. The presence detectors 640 may be, for example, infrared (IR) rangefinders or ultrasonic sensors that detect the presence of solid objects within a specific area. The presence detectors 640 can determine whether a piece of plastic has entered the loader (e.g., loader 104) and, accordingly, allow the controller 628 to operate the loader motor 644. The presence detectors 640 can further detect or sense the estimated volume of plastic in the plastic densification device (e.g., in the storage volume 424).

[0041] The controller 628 may include a display 631 or provide signals to the display 631, which can generally provide user information regarding the current state and operation of the plastic densification apparatus 100. The display 631 may be an LCD display, an OLED display, or any other suitable display. The display 631 may relay information to the user and provide a graphical user interface for receiving one or more inputs from the user (e.g., via a touchscreen and soft keys, or buttons associated with the display).

[0042] The controller 628 can provide the system with one or more outputs 632, including, but not limited to, a compressor motor 642 which may be similar to or different from the lift motor 320 described with respect to Figure 3, a loader motor 644 which may be similar to or different from the loader motor 318 described with respect to Figure 3, a take-out door 646 which may be the cover 106 described in Figure 1 in some embodiments, a cover lock 648, and drive currents or control signals to one or more heating elements 650. The outputs 632 may be electrical signals, digital signals or analog signals, or mechanical signals and outputs (e.g., rotation of a motor or gear).

[0043] In some embodiments where the removal door 646 is automated, the controller 628 can automatically open the removal door 646 when the densification stage is complete for easy removal of the densified plastic. In some embodiments, the cover lock 648 can be activated when the heating element 650 or the compressor motor 642 is operating to prevent the user from easily opening the plastic densification apparatus 100 when the plastic is under high temperature and / or pressure.

[0044] The aforementioned drawings and accompanying descriptions illustrate exemplary processes and systems. However, the systems described (or their software or other components) suggest that any appropriate techniques may be used, implemented, or performed to accomplish these and other tasks. These processes are illustrative only, and it should be understood that the described or similar techniques may be performed simultaneously, in parallel, or in combination at any given time. In addition, many of the actions in these processes may occur simultaneously, in parallel, and / or in an order different from that shown in the illustrations. Furthermore, the systems and flows described may use processes and / or components that involve or perform additional actions, fewer actions, and / or different actions, as long as the methods and systems remain appropriate.

[0045] In other words, while this disclosure describes specific embodiments and generally applicable methods, modifications and substitutions of these embodiments and methods will be obvious to those skilled in the art. Therefore, the above description of exemplary embodiments does not define or limit this disclosure. Other modifications, substitutions, and alterations are possible without departing from the spirit and scope of this disclosure.

Claims

1. A plastic densification apparatus comprising: a controller configured to control operation of the plastic densification machine; a body at least partially enclosing an interior volume having an aluminum interior surface; a cover hinged to the body and pivotable open to provide access to the interior volume; a loading port in the cover configured to allow plastic to be loaded into the interior volume; a loading mechanism attached to the loading port, a roller having a friction surface and configured to grip and pull plastic into the body; a comb attached to the roller, the comb configured to remove plastic from the roller and deposit it through the loading port; a roller motor configured to rotate the roller; a lift within the body configured, upon actuation, to reduce the interior volume and compress plastic within the interior volume; a lift motor configured to operate the lift; a current sensor for measuring a current supplied to the lift motor; a heating element located beneath and in contact with the aluminum surface, the heating element configured to heat the plastic within the body to a temperature in the range of 100°C to 145°C; A temperature sensor for measuring a temperature inside the main body. Plastic densification equipment.

2. the controller is configured to adjust the power supplied to the heating element to maintain a temperature sensed by the temperature sensor within a range of 100° C. to 145° C.

2. The plastic densification apparatus of claim 1.

3. the controller is configured to apply a current to the lift motor up to a predetermined threshold, the predetermined threshold being a current associated with a desired amount of compression of the plastic; 2. The plastic densification apparatus of claim 1.

4. a sight glass in the body to allow visual inspection of the plastic within the body; 2. The plastic densification apparatus of claim 1.

5. A system for densifying plastics, comprising: a controller configured to control operation of the system; a body at least partially enclosing an interior volume having an aluminum interior surface; a cover hinged to the body and pivotable open to provide access to the interior volume; a loading port in the cover configured to allow plastic to be loaded into the interior volume; a loading mechanism attached to the loading port, a roller having a friction surface and configured to grip and pull plastic into the body; a comb attached to the roller, the comb configured to remove plastic from the roller and deposit it through the loading port; a roller motor configured to rotate the roller; a lift within the body configured, upon actuation, to reduce the interior volume and compress plastic within the interior volume; a lift motor configured to operate the lift; a current sensor for measuring a current supplied to the lift motor; a heating element located beneath and in contact with the aluminum surface, the heating element configured to heat the plastic within the body to a temperature in the range of 100°C to 145°C; A temperature sensor for measuring a temperature inside the main body. system.

6. the controller is configured to adjust the power supplied to the heating element to maintain a temperature sensed by the temperature sensor within a range of 100° C. to 145° C. The system of claim 5.

7. the controller is configured to apply a current to the lift motor up to a predetermined threshold, the predetermined threshold being a current associated with a desired amount of compression of the plastic; The system of claim 5.

8. a sight glass in the body to allow visual inspection of the plastic within the body; The system of claim 5.

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