Patent Application
20240158969
The embodiments discussed in the present disclosure are generally related to a method and system to manufacture materials for building insulation. In particular, the embodiments discussed are related to a method and system to manufacture a continuous insulation sheathing product made from hemp-based natural fibers and a non-toxic fire retardant.
Various building insulation techniques are conventionally implemented to reduce heating (or cooling) costs. However, a challenge associated with the conventional insulation techniques is that certain portions in the insulated building are relatively more heat conducive than the remaining portions, thereby, causing a phenomenon known as ‘thermal bridging’. Thermal bridging may cause a relatively higher heat loss from the building and eventually, increase consumer energy expenses for the building. An additional challenge associated with the conventional building insulation techniques is that the materials used in these techniques may contain toxic materials, and result in high embodied carbon emissions, resultant from their synthetic formulations.
Therefore, there is a need to overcome the above-described challenges with the conventional insulation techniques.
Embodiments of a hemp-based continuous insulation sheathing product and a corresponding method and system to manufacture the product, are described to overcome the challenges associated with the conventional mechanisms of building insulation.
The embodiments presented herein describe a hemp-based continuous insulation sheathing product to make a building energy efficient and reduce the carbon footprint of the building. The continuous insulation sheathing product also incorporates a specialized fire-retardant chemical in addition to hemp-based natural fibers. In an embodiment, the continuous insulation sheathing product may be formed via an entanglement and thermal bonding of the natural fibers and a staple fiber. The embodiments presented herein, thus, enable the product to add additional insulation value to roofs and wall assemblies of a building, while providing a continuous layer of thermal resistance performance to mitigate the loss of energy through more conducive members of the roof and wall assembly (e.g., wood or steel framing). Further, the product achieves the above-described advantages using predominantly bio-based materials, thereby, resulting in a lower carbon footprint and providing an environmentally friendly option for consumers.
In an embodiment, a method for manufacturing a hemp-based insulation material such as, the continuous insulation sheathing product, is also disclosed. The method includes combining a predefined proportion of hemp fibers and bonding fibers through a mechanized bale opening process, into a transversal collector, to form blended fibers. The mechanized bale opening process includes mechanically opening the hemp fibers and the bonding fibers from baled form and metering them to the predefined proportion before combining them. The method further includes feeding the blended fibers to a fiber opening willow to refine the blended fibers and then, transporting the blended fibers to a blending box to store the blended fibers. Herein, a first layer of a fire-retardant is sprayed on the blended fibers as the blended fibers are transported into the blending box. The method further includes conveying the stored blended fibers from the blending box to a fine opener to further refine the blended fibers. The method further includes conveying the refined blended fibers from the fine opener to an airlay unit to aero-entangle the refined blended fibers into a fibrous matrix of airlaid fibers. Herein, a second layer of the fire-retardant may be sprayed on the refined blended fibers during the conveyance from the fine opener to the airlaid unit. The method further includes applying thermal compression, in a thermal bonding oven, to the airlaid fibers to bond the hemp fibers and the bonding fibers together to form thermally compressed fibers. The method further includes cooling, through a cooling unit, the thermally compressed fibers to form the hemp-based insulation material that can be used later for building insulation.
In an embodiment, a system for manufacturing a hemp-based insulation material such as, the continuous insulation sheathing product, is also disclosed. The system includes a bale opener configured to mechanically open and meter hemp fibers and bonding fibers from baled form to an opened form. The system further includes a transversal collector configured to combine the hemp fibers and the bonding fibers in a predefined proportion. The system further includes a fiber opening willow to refine the blended fibers. The system further includes a blending box configured to receive the blended fibers for their storage. The system further includes a spray system configured to spray a first layer of a fire-retardant on the blended fibers as the blended fibers are transported into the blending box. The system further includes a fine opener configured to further refine the blended fibers. The system further includes an airlay unit configured to receive the refined blended fibers from the fine opener and aero-entangle them into a fibrous matrix of airlaid fibers. Herein, the spray system is configured to spray a second layer of the fire-retardant on the refined blended fibers during the conveyance from the fine opener to the airlay unit. The system further includes a thermal bonding oven configured to apply thermal compression to the airlaid fibers to bond the hemp fibers and the bonding fibers together to form thermally compressed fibers. The system further includes a cooling unit configured to cool the thermally compressed fibers to form the hemp-based insulation material.
Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings:
The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. Various modifications to the preferred embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. The present invention is not intended to be limited to the embodiments shown but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.
The embodiments of the methods and systems are described in more detail with reference to
In an embodiment, the board 100 may be manufactured from natural fibers, such as, but not limited to, hemp, flax, wood, sisal, jute, and other plant-based fibers averaging approximately 2″ in length for the purpose of creating a low embodied carbon and partially biodegradable building material.
In an embodiment, a “staple” fiber may refer to a fiber responsible for bonding the natural fiber(s) via aero entanglement. The staple fiber may include, but not limited to, a polyester bi-component fiber, a Polylactic acid (PIA) fiber, or a or a low-melt bonding fiber of a polymer origin. The staple fiber may be bonded with the natural fibers and may be airlaid, carded, or wet laid and then, thermobonded. These aspects are described in more detail in the context of
In one example, the joints between boards may either be “tongue and groove” joints 202, 204 to fit into one another, as illustrated in
In an embodiment, the board 100 may be manufactured via a nonwoven insulation manufacturing process that may involve opening bales of fibers and subsequently, blending them in predetermined ratios by weight. Further, the process may involve treating the fibers in-line with aerosolized fire retardant and subsequently, forming the fibers into a mat. Further, the process may involve bonding and compressing the fibers together through an oven and then, coating the surface of the bonded mat with a second application of a fire retardant in one embodiment. Subsequently, the process may involve cutting the mat by length and width to achieve the board 100's final form. These aspects are described in more detail in the context of
Prototypes of the illustrated board 100 have been created by the inventors using airlaid nonwoven manufacturing techniques to determine the feasibility and insulation value of the product. The resulting hemp-based continuous sheathing insulation product is a unique formulation that may add insulation to buildings in continuous form to reduce thermal bridging. Additionally, this formulation and manufacturing process allows for the use of bio-based fibers that are advantageous from a carbon footprint, toxicity, and biodegradability standpoint. The illustrated product may also incorporate a fire-retardant that makes the use of plant-based fibers possible while also making the building code compliant.
In step 402, hemp fibers and bonding fibers are transported into a manufacturing facility for manufacturing the disclosed hemp-based insulation material. An exemplary manufacturing facility is illustrated in the context of
Referring to step 402, in an exemplary scenario, industrial hemp fiber is cultivated from seed genetics designed to contribute the plants photosynthetic energy to growing robust stalks that are high in fiber content. Stalks are grown in row-style cropping with planting densities specific to regionality, latitude, and other environmental factors. Stalks are grown to maturity and are cut with agricultural harvesting equipment that lays the stalks down in the field. The stalks are left to rett, wherein retting is a process that refers to allowing microbial decomposition of the stalks to occur. This results in fiber that is more supple, as well as more easily able to be separated from the other plant part constituents, such as the inner wooden core, referred to as ‘shiv’. After retting, the stalks are baled with agricultural machinery. They are then transported to a decortication facility for further processing.
Further, several bales of retted stalks, referred to as straw, enter a decortication system through the first step of bale opening. The square or round bales are then run through a series of cutting units that separate the outer fiber from the inner wooden stalk (shiv). The shiv and fiber are continually separated through mechanical processes. The shiv is diverted from the fiber and sieved, cleaned of dust, and bagged at the end of the mechanical process. The fiber is further refined through fiber opening machinery, where dust is extracted, and the finished fiber is sent to a baling press.
After the fiber is baled, the decortication process of fiber is considered complete. Bales of hemp fibers (or other natural fibers) are then transported to a manufacturing facility for manufacturing a hemp-based insulation material for installation in commercial or residential buildings for insulation. In one example, natural fibers, such as hemp fibers, are transported to the manufacturing facility, where they are converted into rigid continuous insulation sheets containing thermally resistive properties for the improved energy performance of built structures. Simultaneously, polymeric or non-polymeric bonding fibers are also transported to the manufacturing facility, opened from bale form, and metered out to a desired weight ratio.
In one embodiment, the above-described bale opening process may be mechanized and the fibers may be opened from the baled form to an opened form, mechanically. In one embodiment, the bale opening process may be implemented within the manufacturing facility prior to releasing the hemp fibers and the bonding fibers into the transversal collector for combining them. For instance, a bale opener may open the hemp fibers and bonding fibers from a baled form to an opened form and meter them to determine a proportion of the hemp fibers and the bonded fibers that is desired to be combined in the subsequent steps. In yet another embodiment, the bale opening step may be integrated with the subsequent step 404 of combining the hemp fibers and bonded fibers.
In step 404, the metered hemp fibers and bonding fibers are released into a transversal collector in the manufacturing facility. The transversal collector combines the bonding fibers and hemp fibers in a predefined proportion, in step 406. Once combined, the transversal collector yields blended fibers that include the hemp fibers combined with the bonding fibers.
In an embodiment, it may be desired that the hemp-based insulation material includes a composition of hemp fibers, bonding fibers and fire-retardant. In one example, the composition may include 10-90% by weight of hemp fiber and 10-90% by weight of polymeric or non-polymeric bonding fibers. Additionally, the composition may also include a fire retardant in the range of 2-8% by weight. However, the preferred formulation of hemp fiber in the composition may be 60-70% and that of the bonding fibers may be 30-40%. The preferred range of the fire-retardant may be 2-8%, in the composition.
In the above embodiments, a wide range of compositions for both hemp fiber and bonding materials is possible. The hemp fiber composition is optimized for thermal resistivity and moisture management as well as vapor permanence. The higher the bonding content, the stiffer and rigid the resulting insulation material, although a correlation exists between increasing bonding material content and reducing natural fiber content that reduces the thermal resistance. The proportion of the natural/hemp fibers and the bonding fibers is a function of desired performance characteristics as well as the desired use case. Higher bonding content may be desired for exterior applications whereas interior applications may require less bonding content. Therefore, the proportion of the hemp fibers and the bonding fibers may be predefined by the manufacturer depending on the desired performance characteristics of the insulation material.
The below table illustrates various combinations of the hemp fiber and bonding fiber:
In one example, the hemp fibers may be substituted by any other known natural bast fibers, in the composition of the insulation material. The composition may include polymeric bonding fibers such as, but not limited to, recycled Polyethylene sheath with polyester core. The composition may additionally include a fire-retardant such as, but not limited to Ammonia Salts based fire retardant with a borate-based additive (e.g., disodium octaborate tetrahydrate additive).
In step 406, the transversal collector may accordingly combine the hemp fibers and the bonding fibers in a predefined proportion.
In step 408, the transversal collector transports the blended fibers (i.e., hemp fibers and bonding fibers combined) into a fiber opening willow. The fiber opening willow includes an arrangement of rotating drums with spikes that orient the fibers, combs the fibers, and removes impurities. Additionally, dust is also siphoned off from the fibers and fed to a separate dust collection system.
In step 410, the refined blended fibers are then transported to a blending box that stores the refined blended fibers. In an exemplary scenario, the blended fibers arrive in the desired proportion in the blending box. The blending box serves as a fiber storage hopper to feed the fibers to the following steps such as, but not limited to, fine opening and airlaying of the fibers.
In an embodiment, a spray system sprays a layer of a fire-retardant on the blended fibers as the blended fibers are transported into the blending box. By spraying a small amount of the fire-retardant solution directly within the blending box, the advantage is that there is dwell time within the blending box, allowing the fibers to uptake the fire-retardant solution into the cellulosic structure of the hemp fibers. This is a benefit, because the fibers are exposed to moisture, and that moisture content can dry out before entering the following steps. There is an additional step of fiber opening, which is a preparation step for the formation of the insulation material. This may result in the loss of some of the fire-retardant characteristics, as it is mechanically stripped away from the natural fibers. The advantage of applying fire retardant directly before airlaying the fibers is that it is the last step before the nonwoven matrix is formed. This results in relatively lesser loss of fire-retardant through mechanical processes that may strip it away, resulting in a more effective application process for the treatment of loose fiber. Through treating loose fiber in these steps, fibers can be more uniformly coated on an individualized basis.
In an embodiment, the spray system that sprays the fire-retardant includes one or more nebulizing nozzles, connected to a container holding the desired liquid solution (e.g., the fire-retardant). The fire-retardant is sprayed through spray nozzles using air pressure. The spray nozzles are positioned at various locations within the blending box and spray fire retardant as the blended fibers arrive into the blending box. In one example, this spray nozzle arrangement includes atomizing spray nozzles that are connected through either rigid or flexible piping and connections, which is connected to a pressurized container of the fire-retardant solution.
In step 412, the blending box conveys the stored blended fibers to a fine opener to further refine the blended fibers. The fine opener refines the blended fibers through a similar process as in the fiber opening willow, which results in decreased fiber micron sizes for increased thermal performance. The fine opener is then cleared of fibers through pneumatic transport of fiber, powered by a fan or pneumatic blower.
In step 414, the blended fibers are then conveyed to the airlay unit. The airlay unit aero entangles the fibers into a fibrous matrix of airlaid fibers. During the conveyance process from the fine opener to the airlay unit, the spray system applies an additional layer of the liquid fire-retardant to the blended fibers. In an embodiment, the airlay unit is operated by operators who control its production height, density, and line speed of the mat formation. The production height is determined by the height setting on the airlay unit, and for natural fiber continuous insulation, is produced at a height of 50% or more than the finished material thickness.
In step 416, the airlay unit conveys the unbonded web of airlaid fibers through a thermal bonding oven that uses natural gas burners to bond together the hemp fibers with the bonding fibers. The thermal bonding oven applies thermal compression to the airlaid fibers to form thermally compressed fibers i.e., heat and compression are used to the control the finished height of the product.
In step 418, a cooling unit cools the thermally compressed fibers, which results in the formation of the disclosed hemp-based insulation material. In an embodiment, the hemp-based insulation material may be in the form of a rigid continuous insulation sheet. In an optional embodiment, the hemp-based insulation material is conveyed to a cutting unit that cuts the panels to a desired length and width. The cut-out panels can later be used for installation in commercial and/or residential buildings.
In one embodiment, the hemp-based insulation material may be additionally treated with surface application of fire-retardants, and additional finishing steps such as heating, lamination, or finishes may be applied. The resultant material is then packaged (e.g., by a packaging unit in the manufacturing facility), palletized, and then prepared for use in residential or commercial buildings.
Once the material is sent to its intended location for installation, the material can be further cut with conventional woodworking tools such as a circular saw, a jig saw, or other known wood-cutting tools.
The rigid continuous insulation (e.g., cut-out panels or the continuous insulation sheet) is affixed to a thermal envelope, either on the interior or exterior of the thermal envelope. In the instance of installation on the exterior of the thermal envelope, the boards are affixed with various methods, such as wide crown staples that penetrate the continuous insulation and affix is to the substrate below. This substrate is often wood materials like plywood, oriented strand board, or materials of the like. The insulation panels are adjoined along their edges so that they create a tight seal around the thermal envelope, reducing gaps or voids for improved energy efficiency of the structure.
The natural fiber (e.g. hemp-based) continuous insulation panels are subsequently covered with a weather resistive barrier with vapor permeable characteristics, allowing the natural fiber continuous insulation to maintain vapor permanence.
In one example, horizontal or vertical wooden strips are applied on top of the weather resistive barrier, that is subsequently covering the natural fiber continuous insulation. These wooden strips can vary in thickness, but they are affixed to the structure, through the weather resistive barrier, through the continuous insulation, to the structural members below, such as dimensional lumber or metal framing studs. The assembly is completed with a desired finish material, such as wood siding or decorative panels that serve as long term finishing materials for weather resistivity and aesthetic purposes.
In an embodiment, opening and blending section 602 may receive several fibers and blend them together for subsequent processing. This process may open compressed bales of natural and synthetic fibers, thereby lengthening the fibers and reducing tangles and incohesive groupings of fibers through a series of combing of the fibers. The input may be compressed bales of fiber and the output may be a fiber that is ready for the next step of airlaying, bringing fibers to contain characteristics more suitable for the subsequent steps. Additionally, opening and blending section 602 may mix the variety of fibers, including a low melt bonding fiber.
Further, in an embodiment, airlay unit 604 may use propelled air and suction to create a fibrous web that forms a mat of varying thicknesses and densities. The randomized fiber matrix may result in a homogenous fibrous mat that has polymer fibers interspersed throughout the mat. In an embodiment, thermal bonding oven 606 may utilize gas burners to ignite and burn natural gas at a desired temperature that is specified to lightly melt the polymer fibers, creating interstitial bonding between the natural fibers and the polymer bonding fibers. Further, the thermal bonding oven 606 may recirculate heated air and use fans as well as suction to create desired properties depending on the end use application.
In an embodiment, the cutting unit 608 may use a series of circular blades and a guillotine blade powered by motor drives and compressed air that cut the nonwoven mat to desired widths and lengths.
Further, in an embodiment, the spray system 610, that may be a custom designed apparatus designed for the purpose of spray applying a chemical emulsion or a desired solution to one or more surfaces of nonwoven materials (including nonwoven mat).
In an embodiment, the centralized filter 612 is a filter system (similar to a dust collection system illustrated in
In an embodiment, a nonwoven material panel manufactured from manufacturing facility 600, may be in the form of a flexible planar sheet that is made from several bonded fibers. The nonwoven material panel may include a top surface and a bottom surface, in accordance with some embodiments of the present disclosure.
The terms “comprising,” “including,” and “having,” as used in the claim and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term “one” or “single” may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” may be used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition, or step being referred to is an optional (not required) feature of the invention.
The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention. It will be apparent to one of ordinary skill in the art that methods, devices, device elements, materials, procedures, and techniques other than those specifically described herein can be applied to the practice of the invention as broadly disclosed herein without resort to undue experimentation. All art-known functional equivalents of methods, devices, device elements, materials, procedures, and techniques described herein are intended to be encompassed by this invention. Whenever a range is disclosed, all subranges and individual values are intended to be encompassed. This invention is not to be limited by the embodiments disclosed, including any shown in the drawings or exemplified in the specification, which are given by way of example and not of limitation. Additionally, it should be understood that the various embodiments of the networks, devices, and/or modules described herein contain optional features that can be individually or together applied to any other embodiment shown or contemplated here to be mixed and matched with the features of such networks, devices, and/or modules. While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein.
This application claims priority under 35 U.S.C. § 119(e) of the co-pending U.S. Provisional Patent Application Ser. No. 63/424,745, filed Nov. 11, 2022, and titled “NATURAL FIBER CONTINUOUS INSULATION SHEATHING” which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63424745 | Nov 2022 | US |
