Patent Application
20130020734
This invention relates generally to handling of plastics prior to recycling. More specifically, the present invention relates to a machine for the transformation of recyclable plastics into a clean, densified form, that is fungible.
The market for plastics has continued to grow, and touches our daily lives in every form from packaging to direct use. The rapid pace at which the plastics market has grown creates a situation where there is an opportunity to better collect and capture the value from plastics packaging before it is discarded and sent to our landfills. The following facts highlight the need as of 2010:
Despite the inherent difficulties and low adoption rates for recycling plastics, there is a great economic and environmental need to do so. Plastics are generally derived from petrochemicals. As such, increases in oil commodity prices have a substantial impact upon the cost to manufacture new plastics. As oil prices are expected to rise as oil supplies are diminished, the cost of new plastic materials is expected to also increase. Over the past two years (2009-2010), the value of recyclable plastics has climbed by 20 percent thereby highlighting 1) the effects of demand outstripping supply for recyclable plastics, and 2) impact of oil as a key input.
Additionally, there is an enormous environmental impact of waste plastic. Plastics exist nearly indefinitely when disposed of. Often plastics are in the form of bags or containers. These plastics are relatively light compared to surface area, and can be blown from landfills and contribute substantially to marine pollution. Marine animals often ingest plastics, and plastics form massive floating “garbage patches” in the oceans. Recycling of plastics dampens the wild swings of plastic prices caused by oil price fluctuations. Recycling also keeps these plastics out of our waste streams, thereby reducing pollution, and in particular marine pollution.
Despite these good reasons for recycling plastic materials, plastics are recycled at a much lower rate than other recyclable materials. For example, in 2005, about 80% of newspaper material was recycled, and 70% of corrugated fiberboard was recycled, and yet only 27% of plastic bottles were recycled (and only 7% of all recyclable plastics were recycled). This low recycling rate can be attributed to a number of factors, including lack of knowledge about which plastics may be recycled, habit, and very low density of recyclable plastics. Knowledge and habits may be addressed through education of the consumer, but plastic recycling standards to create financial incentives around fungible units of trade and density cannot be so readily addressed.
There are 5 major barriers to increasing recycling today:
Given these barriers, it is understandable why the recycling rate for plastics is so low in the US, and has not improved with time, despite the public outcry on this topic.
Density of the recyclable material has a large impact on recycle rates. Paper products are the most widely recycled products and have a high density. Aluminum cans are readily compressed at home and are recycled at a lower rate than paper materials, but at nearly double the rates of plastics. Conversely, plastic bottles and shopping bags are not easily compressed. An entire 13 gallon garbage bag filled with plastic bottles weighs only a few ounces. Transporting plastics bottles to a recycling center is burdensome on a consumer. Even when home recycling is available, a consumer may be hesitant to fill up their recycling container with bulky plastics.
Further, the low density of plastics makes recycling less economical for waste companies due to transportation inefficiencies. Although most waste management transportation trucks include mechanical compressors capable of crushing the plastics to a more dense state, plastics tend to be highly elastic and, even when compressed, tend to resist densification.
The ability to densify plastics by the consumer would have a number of benefits: 1) it would reduce the cost of transportation of plastic materials from the consumer to a recycling plant, 2) it would promote increased recycling rates of plastic materials, and 3) it would enable a more effective monetization of recycled plastic materials.
However, mere densification, while increasing recycle rates, is insufficient to substantially promote consumer recycling. In order to do so, the densified plastic must be made a fungible commodity. By fungitizing recyclable plastics, a market can be generated to increase plastic recycling adoption rates.
The prior art has failed to recognize the problems associated with recycling plastic in a manner that is enticing and financially rewarding to a consumer, waste management company and recycler, that will enable recycling rates to improve. Given the lack of effective solutions, it is understandable why plastics recycling have only achieved a 7% rate in United States.
It is therefore apparent that an urgent need exists for a system and method for densification of recyclable plastics that creates fungible output. Such a system and method would increase recycling rates of plastics by creating financial incentives/standards for consumers and reducing transportation costs of plastics to recycling facilities, and costly processing and handling.
To achieve the foregoing and in accordance with the present invention, a system and method for densification of recyclable plastics is provided. Such a system and methods enables reduced cost of transporting plastics for recycling, greater recycling compliance, and commoditization of plastic recycling through the densification of plastic into fungible ingots or storage canisters.
Some embodiments of the densification and fungitization apparatus may include a single hopper for receiving a wide variety of plastic materials and converting them into a single mixed plastic ingot. Alternate embodiments may include multiple hoppers in order to receive specific species of plastic in each hopper (as distinguished by the resin identification code). In yet other embodiments, a single hopper may be utilized, but the user selects which plastic type is inserted, and only similar plastics are melted into ingots together.
After the plastic is inserted into the hopper, a shredder grinds the plastic into plastic shreds which are suitably sized for subsequent melting and compression into an ingot. A vacuum system may separate out plastic bags from plastic containers in the hopper prior to grinding in order to reduce the chance of shredder binding. The system meters the quantity of shredded plastic within the hopper for a threshold level required to generate an ingot. Once that level has been reached, a conveyer may transport a set volume or weight of the plastic shreds to a compression cylinder.
In the compression cylinder, once compressed, the plastic shreds are heated and compressed further, using a heating element, to above a minimum melting temperature. In some embodiments, the minimum melting temperature is a melting temperature above a lowest melting temperature of the mixed types of plastics. In yet other embodiments, the minimum melting temperature is about just above 400 degrees Fahrenheit, and depends on the type of plastic. Other plastic compositions may have lower or higher melting temperatures.
The melted plastic is then compressed via a piston into a mold for the generation of the ingot. The ingot may be a coin in some embodiments. The coin may have a distinctive shape, size or embossment (such as barcode or logo) to identify any of source, branding, content/composition, weight, value, date, etc.
In some alternate embodiments, the shredded plastic may be transported into a compressive cylinder which does not heat the plastic. Rather, such a system may compact the plastic shreds into a canister or other suitable container for ease of recycling. Removal of the heating element reduces power consumption, apparatus complexity and cost, but the tradeoff is a less densified end product.
Note that the various features of the present invention described above may be practiced alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.
In order that the present invention may be more clearly ascertained, some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:
The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, to one skilled in the art, that embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of embodiments may be better understood with reference to the drawings and discussions that follow.
The present invention relates to a system and methods for the densification of recyclable plastics. As previously noted, plastics, in the form of bags and bottles, are generally not very dense due to trapping of air and elasticity of the product in the shape in which it was molded. This leads to larger bulk when recycling these plastics, which often decreases a user's propensity to recycle, and raises transportation costs to transport these materials to a recycling center. Embodiments of the disclosed system and methods enables reduced cost of transporting plastics for recycling, greater recycling compliance, and commoditization of plastic recycling through the densification of plastic into fungible ingots or storage canisters.
One important aspect of disclosed embodiments is the ability for the densification and fungitization system to be readily usable in a residential setting by average consumers. In order to achieve this level of consumer orientation, a number of user friendly features and safety measures have been incorporated into the system. These may include any of one-touch operation, shielding from grinders, emergency shutoff switches, tilt sensors, electrical circuit through the lid so the unit is inoperable when open, locks, heat shielding and dissipation measures, and air/particulate filters. These and other features will be discussed in greater detail below.
To facilitate the discussion,
In this example figure, the exterior of the densification apparatus is illustrated. The densification apparatus includes an external housing 102 and a lid 104. A handle 108 couples to the lid 104 in order to access the interior of the densification apparatus. In some embodiments, the lid 104 may be opened by a foot pedal, or automatically (e.g., using IR sensors). Additionally, the densification apparatus includes a dispenser 106 for collection of the densified plastic after operation.
A set of controls 110 may also be included on the densification apparatus for operation. The controls 110 may be found on the external housing 102, as illustrated, or on the lid 104, in some embodiments. Typically, the controls 110 include an on/off switch, display and cycling switch. In some alternate embodiments, the cycling switch may be omitted and internal sensors may measure if plastic material has been deposited within the densification apparatus. In these embodiments, the densification apparatus may cycle after the lid has been closed. The controls 110 may also include an emergency shutoff switch for added safety. Further, the entire unit may include a tilt sensor that automatically shuts off the system when it has been tipped over. The tilt sensor may be a bottom switch, accelerometer or any other directional finder.
Additionally, in some embodiments, the controls 110 may also include a plastic bag receiving switch which initiates a vacuum at port (not illustrated) which sucks in thin film plastic bags. The vacuum port may be directly available when the lid is opened, or may be accessible from the exterior of the system.
Additionally, a barcode scanner 112 is seen in this embodiment. The barcode scanner may be utilized by the user to identify the type of plastic composition a container has prior to it being densified and converted into a fungible asset. Most commercial containers include existing UPC barcodes. These barcodes may be compared to an internal database for determination of composition. The database may, in some embodiments, be periodically updated through firmware updates, or even by wireless connectivity. Alternatively, standardized barcodes may be adopted by the manufacturing sector which includes material data; the barcode reader may gather composition from scanning these standardized barcodes.
By determining the composition of the material being recycled, the system is capable of adjusting process conditions such as heating temperature and time. Further, the final product generated may be marked or manufactured to indicate the composition. Although not illustrated in the following examples, some systems may include more than one compressive cylinder, and may therefore generate streams of recyclable plastics that are of pure compositions (as opposed to mixed plastic output).
Alternatively, some embodiments may include a number of sized holes once the lid is opened in order to manually sort the plastics. One such hole may be for plastic bags and films which are commonly polyethylene (PE). A second hole may be sized for beverage bottles, such as bottled water and soda. These containers are generally manufactured from Polyethylene Terephthalate (PET). Lastly, there may be a general waste space for remaining mixed plastics.
In addition to the computer systems which operate the system, some embodiments may further include a wireless antenna and control logic. Including a wireless communication system provides a few distinct benefits. These include being able to update composition databases (useful when the system is outfitted with a barcode reader). Further the wireless communicator may send operational data to a data center via the internet or other suitable network. Operational data may be useful in troubleshooting the unit if it requires repairs, and further may be utilized to keep track of the number and type of fungible plastic ingots produced by each machine. This data may be utilized to prevent counterfeit ingots from being produced, and ensures fidelity in the market.
In the example illustration, the external housing 102 and lid 104 have been made partially transparent to show a hopper 304. A depressor 302 coupled to the lid 104 can press on a compression plate within the hopper 304 in order to push plastic materials down, in some embodiments. The depressor 302, which pushes plastics toward the grinders, may be driven by springs, pneumatics, or by motor.
Coupled to the hopper 304 is a conveyer 308 which transports the plastics to a compressive cylinder 306. Around the compressive cylinder 306 is a cylinder wrap 310. The cylinder wrap 310 may include both a thermal blanket and an insulating layer. The thermal blanket may include heating coils which are configured to heat the compressive cylinder 306 to a temperature required to melt at least one component of the incoming plastic. In alternate embodiments, the cylinder wrap 310 may include only an insulating layer and the heat for melting the plastic may be supplied by superheated air blown over/through the plastic for a set period of time.
In some embodiments, the compressive cylinder 306 may include a thermocouple or other suitable device for modulating temperature. In some alternate embodiments, the densification apparatus may be pre-calibrated to reach the desired threshold temperature without the need for temperature feedback.
The insulating layer reduces the amount of heat lost from the compressive cylinder 306 to the other internal systems. However, no matter how good the insulation layer is, some heat is lost. In some embodiments, the amount of heat lost is minimal and will dissipate without any issues. In some alternate embodiments, such as that illustrated presently, the fan 204 may increase airflow around the compressive cylinder 306 in order to reduce excess heat. Additionally, the fan 204 may be integrated into an air filtering system. The melting of plastics is prone to generation of volatile gasses. These gasses are unpleasant to smell, and may pose a health risk. The densification apparatus may be manufactured to airtight specifications to minimize the amount of gasses which escape. However, some gas is likely to escape the compressive cylinder 306, so a pressure gradient in the system generated by the fan 204 may force any escaped gas through a filter 202, such as a HEPA filter, carbon filter, or other suitable filter, to remove these smells and/or harmful gasses/particulates prior to venting to the environment.
The hopper 304, conveyer 308 and compressive cylinder 306 should be made from suitably durable materials. In the case of the compressive cylinder 306, the materials must also be heat resistant, and not readily bound by melted plastics, in some embodiments. Thus, the hopper 304 and conveyer 308 may be manufactured from any combination of metals, plastics, ceramics or any other suitable materials. The compressive cylinder 306 may likewise be made of metal, ceramics, or other suitable material (such as high temperature resistant resins). In some embodiments, the compressive cylinder 306 may include a heat conductive metal with the interior coated with Teflon®, chrome plated, or other suitable non-stick surface.
The bottom of the compressive cylinder 306 may hinge open, as will be discussed in greater detail below. One or more locks 312 may lock the hinged bottom in place during operation as the densification of the plastics requires increased pressure.
The dispenser 106, in this embodiment, is illustrated as a pull out drawer. The dispenser 106 provides a place for the densified plastic to cool prior to being accessed by the user. While the drawer style design is easily locked until the plastic may be handled by the user, other systems are equally suitable for the dispenser 106, such as a conveyer system or a magazine that collects the ingots or coins and can be removed and used as a coin carrying device to the collection facility. Also note that the fan 204, in some embodiments, may be used not only to assist in cooling the compressive cylinder 306 and reducing internal temperatures, but also assists in cooling the densified plastic ingot to a touchable temperature.
Lastly, in this embodiment, the lid 104 is supported by two rods 406, thereby allowing for vertical opening and closing of the lid 104. This is a design consideration as it allows the depressor 302 and compressive plate to be lowered into the hopper 304 vertically which has some advantages. However, it is equally possible that the lid 104 is hinged, in some embodiments. In either case, an electrical circuit for the operation of the system may be routed through the lid 104, thus unless the lid 104 is closed the unit will not be operable.
Plastics placed within the hopper 304 are ground by the shredders 506 and transported by the conveyer 308 to the compressive cylinder 306 for melting and compression. The conveyer 308 may include any conveyer type system, however here an auger 508 is illustrated as moving the ground plastic particles to the compressive cylinder 306. An auger 508 has two advantages: 1) it provides a seal between the compressive cylinder 306 and fan 204, which minimizes the volatile gasses generated during melting from flowing up and out through the hopper 304; 2) the amount of ground plastics entering the compressive cylinder 306 may be tightly controlled. It is important that the proper amount of plastic is incorporated into each plastic ingot in order to make them fungible. Furthermore, the amount of heat, mold size and pressure required to generate an ingot is dependent upon amount of plastic, thus metering out a consistent level of plastic grinds is important.
The bottom view 700 of the densification apparatus also illustrates important safety features including a latch 702 and sensor 704. While the lid 104 is open, the shredders 506 are inoperative and the shield 504 is covering the shredders 506 due to feedback from the sensor 704 (the sensor may alternatively include a circuit breaker type design with electricity flowing through the lid in order to be operable). This prevents inadvertent mangling of a person's hand when the lid 104 is open. When the lid 104 is closed and a cycle is started, the latch 702 locks the lid 104 closed in order to ensure the cycle is not disrupted and for safety purposes. The latch 702 may be driven by any actuator type, such as motor or solenoid.
A level sensor determines when enough ground plastic has been generated to produce an ingot via height or weight of the ground plastic. Once sufficient plastic has accumulated, the auger 508 transports a set amount of the ground plastic to within the compressive cylinder 306.
Plastic bags may be handled in a similar manner. In some embodiments, plastic thin film bags are deposited within the hopper 304 and are ground with other plastic materials. In some embodiments, the thin plastic bags may bind to the shredders 506, so in these embodiments the shredders 506 may periodically reverse in order to disengage the bound plastics. In some alternate embodiments, thin film plastic bags may instead be fed through a port via a vacuum system. These bags may be deposited directly into the compressive cylinder 306, or auger, without grinding. Since the plastic bag material is so thin, these bags do not require grinding before melting and densification. In yet another embodiment, a vacuum port may be located within the hopper 304 below the shredders 506 which engages prior to grinding. This would pull any plastic bags out of the hopper 304 to the compressive cylinder 306 before grinding.
Melting in the compressive cylinder 306 may occur prior to, or simultaneously with compression by the piston 402. Melting temperature may be tightly controlled based upon plastic type being recycled. In a mixed plastic ingot, only the temperature of the lowest melting component is required to be reached in order to bind the ground plastic pieces. Typically, for mixed plastics, melting is performed around 400° Fahrenheit (F), in some embodiments. In alternate embodiments, the melting may be performed at about 270° Fahrenheit. For single composition plastics, different temperatures may be utilized. For example, the melting point of HDPE (High Density Polyethelyne) is about 266° F. The melting point of LDPE (Low Density Polyethelyne) is about 230° F. The melting point of PET (Polyethylene terphthalate) is about 500° F. The melting point of PP (Polypropylene) is about 320° F. The melting point of PS (Polystyrene), EPS (foamed or expanded polystyrene) is about 150-240° F. The melting point of PVC (Polyvinyl Chloride) is about 167-194° F. Too high a melting temperature produces excessive gas byproducts and wastes energy, thus lowest effective melting temperatures are desired.
The compressive by the piston 402 forces the melted or semi-melted plastic down into the mold for forming an ingot. In some embodiments, within the bottom interior of the compressive cylinder is a screen or filter which ensures that only plastic materials are allowed into the mold. In some embodiments, this screen filter may be removed for easy cleaning This ensures that ingots are relatively pure and do not contain undue debris.
After the ingot is formed, the locks 312 may disengage the bottom of the compressive cylinder 306 and the hinge 802 may enable the newly formed ingot to drop down into the dispenser 106. In alternate embodiments, the ingot may be deposited into a magazine, which stacks multiple ingots for easy carrying. The newly formed ingot will be above a handling temperature and will cool prior to being accessed by the user. Generally, any ingot shape or size is possible; however, for a residential system smaller ingots may be preferred due to recycling volumes.
These ingots may be coin shaped, and may be monetized under some business models. Coins may include embossed identification, including identification of plastic type, sponsors (via, e.g., one or more logos), barcodes, source machine, or the like. Further, coins may have different shapes or sizes to distinguish them. This becomes particularly important where the densification apparatus is not a single stream, as illustrated here, but rather a multiple stream system. For example, while a single hopper 304, conveyer 308 and compressive cylinder 306 is illustrated in these figures for clarification purposes, it is entirely possible that some embodiments of the densification apparatus may include more than one hopper 304. Each hopper 304 may correspond to a particular recyclable material, as indicated by the resin identification code on the bottom of a container. Thus, a single densification apparatus may be capable of producing multiple coin types, each coin corresponding to a particular plastic type.
It is also important to note that the generated ingots of particular size, composition, weight and shape are manufactured to conform to a set of standards. These standards enable the ingots to be fungible, and therefore enable a marketplace for these ingots/coins. A retailer, or recycler, may know the value of any particular ingot based upon its shape or identification, and thus they may be readily traded for credit, currency, or discounts.
Once the cycle is started, the depressor 302 extends by motor, pneumatic, or springs into the hopper 304, as illustrated in
Once the coin 1202 has been formed, it may be held temporarily within the compressive cylinder 306 to partially solidify. Then the pins of the locks 312 may retract thereby enabling the mold 1302 at the bottom of the compressive cylinder 306 to open, as illustrated at
After the mold 1302 is open, the driver 404 may drive the piston 402 further down to press the coin 1202 out of the compressive cylinder 306, as indicated in
The method continues by optionally segregating plastic bag material from the hopper utilizing a vacuum system (at 1704). This action of separating out thin film plastic bags may be omitted if the shredders have a self cleaning cycle, or if an exterior port exists for receiving plastic bags.
Next, the plastic remaining in the hopper may be ground utilizing the shredders (at 1706). Shred size may vary based upon unit size, however generally grind sizing is optimized to reduce power requirements for melting and ensuring adequate compressibility. The level of ground plastic is metered (at 1708) for a threshold level. Once the threshold has been reached, a set amount of the ground plastic may be transported to the compression cylinder (at 1710). This material is then simultaneously heated (at 1712) and compressed (at 1714) in order to generate a plastic ingot or coin. The ingot/coin may be of particular shape, size or be embossed with an identification of material contained within it, source, or other relevant information.
While the present invention has been described in a number of embodiments, there are a number of variations that fall within the scope of this disclosure. For example, while a compressive cylinder with a piston has been detailed in a number of the embodiments, it is also considered that an injection molding type system utilizing an auger where the plastic is melted prior to being injected into a mold may be equally suitable with some embodiments. Likewise, while heating coils driven by electrical current are disclosed, heat may be equally supplied by superheated air, or combustion systems.
In addition, in some embodiments a consumable HDPE or other lower melting temperature plastic may be supplied to the system. This consumable binder material may be maintained in a melted state and injected into the mold with the compressed ground plastic in order to bind the ingot. The advantage of this system is that the melting temperature of the binder may be lower than the ground plastic, and the system does not need to heat significantly for each ingot. Likewise, in yet other embodiments, the binder may even include a solvent, resin, or non-heated monomer solution which polymerizes once in the mold.
In some alternate embodiments, the plastic shreds may be compressed without heating. These compressed shredding may be sealed within a canister or other container and deposited at a central collection location. In some embodiments, canisters may be emptied at the collection point and returned to the user for re-use. Additionally, the user may receive a payment for the canister, thereby incentivizing the recycling.
In sum, the present invention provides a system and methods for densification of recyclable plastics. Such a system and methods enables reduced cost of transporting plastics for recycling, greater recycling compliance, and commoditization of plastic recycling through the densification of plastic into fungible ingots or storage canisters.
While this invention has been described in terms of several embodiments, there are alterations, modifications, permutations, and substitute equivalents, which fall within the scope of this invention.
It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and substitute equivalents as fall within the true spirit and scope of the present invention.
