The present disclosure relates to systems and methods for microwave treatment and reconditioning of roadway surfaces, for example, asphalt concrete surfaces. More particularly, it relates to the use of an array of individual microwave cells for heating and treating a width of roadway surface while continuously traversing the roadway. The microwave cells may be arranged in a tiled array and travel as a unit at a constant speed along a treatment surface. The microwave treatment reanimates the existing (and likely damaged) asphalt to a workable state that is almost identical in nature to newly laid asphalt. It is to be appreciated that the present exemplary embodiments are also amenable to other like applications.
Deterioration of asphalt concrete is a nationwide problem, which often necessitates premature replacement of road pavement surfaces. Asphalt concrete is a commonly used composite material to surface roads, parking lots, airports and the like. It consists of mineral aggregate (sand, stones) bound together with asphalt concrete, which is laid in layers and compacted. The performance of asphalt concrete decreases over time as it is subject to deterioration including, but not limited to, cracking, potholes, upheaval, raveling, bleeding, rutting, shoving, stripping, and grade depression.
Factors that contribute to asphalt concrete deterioration include construction quality, environment, and traffic loads. For example, moisture damage in asphalt concrete contributes to adhesion failure between the concrete and the aggregate as well as cohesion failure within the asphalt concrete itself. Adhesion failure occurs when moisture accumulates between the asphalt and concrete and lifts the asphalt film away. The cohesion failure occurs when moisture causes a reduction in cohesion within the asphalt cement, reducing integrity and strength.
Repair of an asphalt concrete surface generally consists of filling cracks, surface imperfections, and potholes with an asphalt mix and other surface treatments, e.g., filling with a bituminous crack sealer. These repairs do not possess the same durability of the original pavement and will likely need to be repeated over time until the entire road is repaved. When the deterioration of the roadway necessitates replacement, conventional methods for repaving a road is costly. This is because repavement involves fleets of different heavy machinery. To repave a road, such as a highway or a city street, the road/lane(s) needs to be blocked off and the damaged road surface will need to be removed, requiring a large crew of workers and specialized machinery. The remaining surface is cleaned, and all the removed material is hauled away by large dump trucks. Another set of machines are brought in, to the road site for transporting in and laying down new asphalt.
In some prior treatment methods, asphalt may be reused by combining the removed material with new bitumen. The reused asphalt is used primarily a filler material and may be deteriorated by traditional heating and processing methods. Thus, the durability of roads using reused asphalt is generally known to be poor.
Microwave energy can be used to treat and condition asphalt concrete. Microwave energy is a flameless heat source that internally heats an application area to a certain penetration depth. That is, heating by microwave energy does not rely on conduction of heat inward from the surface; rather, heat is generated within a targeted volume of material. Heat transfer by conduction may take place after the target volume is heated. This application of heat is significant because a desired uniform temperature of material may be reached without overheating any portion thereof.
U.S. Pat. No. 8,845,234, (the '234 patent) entitled “Microwave Ground, Road, Water, and Waste Treatment Systems” (the disclosure of which is herein incorporated by reference) teaches a microwave ground or road heating system for the treatment and repair of roadways. In one embodiment, the treatment system includes a single microwave generator that produces long wavelength microwaves at 915 MHz. The system of the '234 patent is connected to a boom such that a microwave waveguide may be moved and placed to direct microwaves to a limited desired location on the ground. This design suffers from drawbacks in that the system of the '234 patent can only be used to repair small areas in a time-consuming process. The repair of the '234 patent would make the cost of repair prohibitive when a cold patch repair would be quicker and less expensive. Municipalities and townships would, therefore, be reluctant to pay for a repair according to the '234 patent, costing about 20 times more than a scoop of cold patch and by a process that would take about 20 times longer, even though the microwaved repair would last much longer. Furthermore, microwave radiation is directed energy, with little scattering or dispersion. For example, microwave ovens usually include a mode stirrer device used to modify the electromagnetic field within a microwave oven to spread out the microwave energy and improve the uniformity of heating. Thus, a single magnetron and waveguide would have difficulties in applying a significant amount of microwave energy to a large area, e.g., the width of a road. Lastly, the equipment required for the longer wavelength microwaves is considerably large with corresponding large power requirements.
The present disclosure provides certain improvements including, but not limited to, selective treatment across a width of a road to achieve continuous heating while in continuous motion and cost-effective quality road repair. While exemplary embodiments described herein relate to use of microwave applicator cell arrays on a road surface, it is to be appreciated that any asphalt surface may be treated in a similar continuously traveling manner. That is, the exemplary systems and methods may also be used to repair parking lots, paths (e.g., asphalt trails and golf cart paths), driveways, etc.
Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an extensive overview of the disclosure and is neither intended to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary purpose of this summary is to present some concepts of the disclosure in a simplified form prior to the more detailed description that is presented hereinafter.
Described herein are devices, systems and methods that employ an array of microwave applicator cells cooperatively connected a trailer or truck. The array of microwave cells continuously travel and apply microwave energy along a road surface as a unit. The treatment returns the surface back to “as original” without removing or modifying (i.e., breaking up or otherwise manipulating) the roadbed. The array systems described herein are generally configurable to span the width of a standard road lane for increased efficiency for repairing asphalt surfaces. The systems and methods may also have several additional components or sub systems to support repair and operation as described in detail below. These additional components and subsystems include, for example and without limitation, sensors, fluid sprayers, mechanical scarfers, lidar and GPS location.
The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.
A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments.
As used herein, “microwaves” are a form of electromagnetic radiation with wavelengths ranging from about one (1) meter to one (1) millimeter; with frequencies between about 300 MHz and 300 GHz. Use of industrial, scientific and medical (ISM) radio bands including microwaves, is governed by the United States of America, through the FCC. Currently, the two frequencies of 915 MHz and 2.45 GHz are the assigned frequencies for industrial applications of microwave energy. However, it is to be appreciated that other frequencies may be used in accordance with the present disclosure without deviating from the scope thereof.
Microwaves are generated by magnetrons, which are generally commercially available in one of two configurations. First, are the relatively small and inexpensive magnetrons that are readily available and commonly used in household microwave ovens, these generate microwaves of 2.45 GHz. Second, are large and relatively expensive magnetrons, e.g., weighing over 200 lbs. The microwave treatment system of the aforementioned mentioned U.S. Pat. No. 8,845,234 uses such a large magnetron, which takes up significant space in the back of a vehicle. These large magnetrons not only require significant space but also an equally large power source to power the magneton. These generally are configured to generate long wavelengths and frequencies of 915 MHz.
As mentioned briefly above, reusing asphalt for road surfaces results in a road with poor durability. The reused asphalt is used as a filler material. That is, the reclaimed material is heated up and combined with new bitumen material for application to a road surface. When the reused asphalt is re-heated by conventional methods, the heat deteriorates the reused material. This may potentially be due to the uneven application of extreme heat, as conventional methods drive heat into the asphalt itself from the outside of the material to the interior of the material. This is different from microwave application which can heat all portions of the material (interior and exterior) alike.
Applicants have found that the application of microwaves to an asphalt surface “reanimates” existing asphalt to a workable state that is almost identical in nature to newly laid asphalt. That is, the reanimated asphalt exhibits flow and slump similar to freshly created asphalt mixtures. More surprisingly, this workable state may be achieved by using a plurality of small magnetrons, similar to those used in home microwave ovens, operating at about 2.45 GHz. The microwave treatment allows the previously damaged asphalt to self-heal (flow) or be further processed by rollers in repairing and reconditioning a damaged road surface. A microwave treatment system as described herein may replace all the machinery and crew needed to tear up an existing road, haul away the old material, bring in new material, and apply the new material to the road surface. The downtime of a blocked off road is significantly shortened as all that is needed is for a microwave application system to continuously travel down a road and reanimate the damaged asphalt. That is, the systems and methods described herein are able to continuously travel along a distance while it is treating the surface it traverses allowing for efficient reanimation and processing of a damaged road surface.
Exemplary embodiments of the present disclosure relate to microwave application systems and microwave applicator cells for applying microwave energy to a surface. In some embodiments, a plurality of microwave applicator cells are tiled in rows and columns (an array) that span across a desired width, e.g., the width of one standard road lane. Multiple adjacent rows of microwave applicator cells, lined along a length, define a total microwave array length. A vehicle, operatively coupled to the array microwave applicator cells, is configured to travel along a treatment surface at a continuous speed while applying microwaves to the surface.
A microwave applicator cell 100 includes at least a microwave generator 102 and an associated waveguide 104, sometimes referred to herein as a microwave generator and waveguide pair. Each microwave generator 102 is powered by a power source 103 and generates electromagnetic radiation in the form of microwaves. It is to be understood that the microwave application system 100 may have a single power source 103 that supplies electrical power to all of the microwave generators 102 in the system 1 as well as other various components described herein. In alternative embodiments, each microwave generator 102 or microwave applicator cell 100 is associated with its own power source 103, i.e., the microwave application system 100 includes multiple power sources 103. Furthermore, while the power source 103 is illustrated as being carried by a truck 10, it is to be understood that the location of a power source 103 is not limiting. That is, the power source may be carried by the truck 10, or may be attached to at least one of the plurality of microwave applicator cells 100.
The microwaves generated by each microwave generator 102 has a wavelength in the range of about 0.001 m to about 1 m. In some embodiments, the microwave generator 102 is configured to generate microwaves having a wavelength of about 0.122 m (a frequency of about 2.45 GHz). The microwave generator 102 may be variously embodied, including but not limited to as vacuum tube device such as a magnetron, klystron, and traveling wave tube, and/or as a solid-state device such as a field-effect transistor, tunnel diodes, and the like.
A waveguide is a structure for guiding electromagnetic waves from one point to another. Here, waveguide 104 directs the microwave radiation from the microwave generator 102 to the interior of the microwave applicator cell 100 and toward the ground. The waveguide 104 has a first end that is operatively connected to the microwave generator 102 such that the waveguide 104 transfers microwaves from the microwave generator 102 to the waveguide 104. The waveguide 104 guides the received microwaves to interior of the applicator body 108 of the microwave applicator cell 100 such that the microwaves are directed towards and allowed to impinge and penetrate a treatment surface (e.g. the surface of a road) bounded by the applicator body 108. In other words, each applicator body 108 defines the boundaries of the treatment surface that receives microwave energy. The width of each waveguide 104 is generally dimensioned to be of the same order of magnitude as wavelength of the microwaves generated by the microwave generator 102 to minimize waveguide losses. For example, the waveguide 104 is preferably sized in increments of about 0.328 m for 915 MHz microwave radiation and in increments of about 0.122 m for 2.45 GHz microwave radiation. In some embodiments, a waveguide 104 is embodied as a hollow, conductive metal tube. The cross-section of the hollow metallic tube is preferably uniform, and transmits the generated electromagnetic waves by successive reflections from the interior walls of the hollow tube (waveguide 104).
In some embodiments, the waveguide 104 further includes a flared end, often referred to as a “horn,” used to transmit microwaves from the waveguide 104 out into space (e.g., toward the application surface). The flared horn portion forms a smooth transition between the waveguide 104 and free space.
As briefly mentioned above, the microwave applicator cell 100 also includes an applicator body 108. The applicator body 108 may have a top wall 107 (sometime referred to herein as a “ceiling”) and at least one sidewall. In the illustrated embodiment of
With reference to
The top wall 107 is further configured to receive and/or mount the microwave generator 102 and waveguide 104 pair, and allow the generated microwaves to travel into the interior of the applicator body 108 and impinge and penetrate a ground surface. The microwave waveguide 104 may attach to the top wall 107 through means known in the art, including fastening and welding. In some embodiments, the microwave generator 102 and waveguide 104 are positioned and configured such that microwaves generated by the microwave generator 102 enter the interior of the applicator body 108 about the center of the top surface 107. It is to be appreciated that while
In some embodiments, each microwave applicator cell 100 further includes at least one fastening point 118 used to connect adjacent microwave applicator cells 100 together. In some embodiments, a fastening point 118 is located on the top wall 107 about a centerline 115 of a sidewall section 109, however, the location of the fastening point 118 is not limiting. The fastening point 118 may include an aperture 119 configured to receive a fastener for connecting multiple microwave applicator cells 100 together. A fastener may include, for example and without limitation, a threaded bolt and nut, axes and cotter pin, a chain, a shackle, and the like. In some embodiments, and as illustrated in the exemplary embodiment of
In some embodiments, operation of a microwave applicator cell 100 is controlled by a power switch 105. That is, the transmission of electrical power to each microwave cell 100 (and microwave generator 102) is controlled by activating power switch 105. When power is directed to each cell 100/microwave generator 102, microwaves are generated and directed toward the treatment surface. Likewise, to power off a microwave cell 100/microwave generator 102, such microwaves are no longer produced, the power switch 105 may be used to cease the power transmission to each microwave cell 100. The power switch 105 may be variously embodied as known in the art. In some embodiments, a single power switch 105 controls the application of power to all the cells 100 of a system. In other embodiments, individual cells 100 or groups of cells 100 are each powered through a separate switch 105. That is, a system of cells 100 may have multiple power switches 105 that direct electrical power to different cells 100 or groups of cells.
In some embodiments and with reference to
The central computer system 200 may be variously embodied as a personal computer (illustrated), tablet, smartphone or other known device that hosts a software platform and/or application. The central computer system 200 may include a processor 223 that may be any of various commercially available processors, such as by a single-core processor, a dual-core processor (or more generally by a multiple-core processor), a digital processor and cooperating math coprocessor, a digital controller, or the like. The central computer system 200 may also include at least one user interface 202 and/or display 204 configured to present data related to the operation of each of the microwave applicator cells 100 to a user. The user interface 202 may also allow a user to input commands into the central computer system 200 for the monitoring and controlling the various components of the microwave application system 1. The central computer system 200 may be located on the vehicle 10 that is configured to transport the array of microwave applicator cells 100A-D. In other embodiments, the central computer system 200 is a remote device capable of operating the plurality of microwave applicator cells 100 from a distance, e.g., the central computer system 200 is a tablet held by an operator on a job site. The software platform hosted on the central computer system 200 may be an Internet of Things (IoT) platform that is available off the shelf, modified, or designed in-house.
It will be appreciated that the central computer system 200 may be connected to a LAN (Local Area Network) and include any hardware, software, or combinations thereof, capable of implementing the systems and methods described herein. Suitable examples of such hardware include, for example and without limitation, processors, hard disk drives, volatile and non-volatile memory, a system bus, user interface components, display components, and the like. It will further be appreciated that multiple such devices may be used as the central computer system 200 accordance with the subject disclosure. The central computer system 200 may also include a computer communication interface 224 for communicating with a plurality of devices including, but not limited to, each of the microwave cells 100, sensors 150, and remote devices.
In some embodiments, each microwave applicator cell 100 includes various hardware components, including, but not limited to, a control circuitry 122 and a communication interface 124, wherein the communication interface 124 is in electronic communication with the control circuitry 122. The control circuitry 122 and communication interface 124 provide for data communication between a microwave applicator cell 100 and the central computer system 200 via computer communication interface 224.
The control circuitry 122 may include a processor 123 that may be any of various commercially available processors. The processor 123 may control various functions of the microwave cell 100, including the generation of microwaves by at least one microwave generator 102 associated with the applicator cell 100. In embodiments where a microwave cell 100 is associated with multiple microwave generators, the processor 123 may individually control the operation of each generator.
The communication interface 124 also includes circuitry for transmitting and receiving data to and from a central computer system 200 via known methods including, but not limited to, wired transmission and wireless transmission e.g., RF transmission, cellular transmission, satellite transmission, etc. In some embodiments, the communication interface 124 may also receive data transmitted from a server or remote user device, such as a tablet. In some embodiments, application software is executed by the control circuitry 122 (processor 123) for performing commands received by the communication interface 124 from the central computer system 200, server, and/or user device. As an illustrative example and with reference to
In some embodiments, the communication interface 124, 224 is a plug-and-play type card or other type of memory card having an associated interface processor and interface memory. The interface processor may execute preprogramed application software stored within the interface memory for receiving position and other data and communicating such data to a central computer system 200. The communication interface 124, 224 may include additionally known hardware, for example, an antenna, RF transmission means, modem, telephone connectors, ethernet connectors, broadband connections, DSL connections, etc. for transmitting and receiving data.
With continued reference to
In some embodiments, the at least one sensor 150 is in communication with the central computer system 200. In some embodiments, the at least one sensor 150 is attached to a vehicle 10 configured to transport the plurality of microwave cells 100. Generally, the at least one sensor 150 is placed directionally in front of the plurality of microwave applicator cells 100. In other embodiments, the at least one sensor 150 is attached to the applicator body 108 of a microwave applicator cell 100. In yet still further embodiments, at least one sensor 150 is attached to a vehicle 10 configured to transport the plurality of microwave applicator cells 100 and at least one sensor 150 is attached to at least one microwave applicator cell 100.
In some embodiments, the at least one sensor 150 is a temperature sensor. In some embodiments the at least one sensor is a microwave bounce back sensor configured to collect data for the control and operation of the plurality of microwave cells 100. The at least one sensor 150 is configured to collect data relating to the state of the surface prior to, during, or after application of microwave energy to a surface, such that the application (presence or intensity) of microwaves or other treatment processes can be adjusted accordingly via computer system 200.
In some embodiments and with particular reference to
The vehicle 10 is configured to transport the plurality of microwave applicator cells 100A-D in a side-by-side tiled pattern that spans the length of a road lane and along a road surface in a direction of travel 255. The at least one sensor 150 is able detect the presence of debris and road structures 250. Upon detection of a road structure 250, the at least one sensor 150 sends a detection signal 252 to the central computer system 200 indicating the presence of the structure 250 at a particular location on the road surface. Upon receiving the detection signal 252, including location information of the road structure 250, the central computer system 200, selectively commands at least one of the plurality of microwave applicator cells 100A-100D (or microwave generator attached thereto) to cease generating microwaves, based on the received location information of the road structure 250. That is, when the continuously traveling tiled arrangement of microwave applicator cells 100A-D traveling in the direction of travel 255, reaches the road structure 250, the computer system 200 ceases the generation of microwaves by at least one of the attached microwave generators 102C of the microwave cell 100C. Thus, when the microwave application system 1 traverses over the road structure 250, a particular microwave applicator cell 100C (or certain microwave generators 102C attached thereto), ceases microwave treatment. After the microwave applicator cell 100C is determined to be clear of the road structure 250, via continuous travel in the direction of travel 255, the central computer 200 controls the microwave generator 102C of the microwave cell 100C to continue generating microwaves for treating the road surface.
While
In some embodiments and as illustrated in
In other embodiments, the tessellation arrangement of the plurality of microwave cells is a semi-regular tessellation—made of two or more regular polygon shapes. For example and without limitation, the tiled arrangement may consist of both triangle shaped microwave applicator cells 300 and hexagon shaped microwave applicator cells 400. In yet still other embodiments, each microwave applicator cell is shaped such that the tiling of cells create a substantially continuous coverage of a treatment area, for example, each microwave applicator cell 100 could be circularly shaped and arranged similarly to the cells 400 or 500 of
With continued reference to
The efficiency of a microwave application system, such as the microwave application system 1, may be increased by increasing the dielectric loss properties of the treatment material (e.g., asphalt). Generally, “dielectric loss” quantifies a dielectric material's inherent dissipation of electromagnetic energy. Applicants have found that the dielectric constant of asphalt and dielectric loss can be increased by adding moisture to the asphalt. Based on the known dielectric loss of water (approximately 13), the dielectric loss of a water/asphalt aggregate can be increased from the literature value of 0.2 up to a composite value of 5, indicating higher loss. An increase in the value for dielectric loss means that the asphalt layer will be able to absorb a greater percentage of the applied energy. Thus, in some embodiments, the application of moisture to asphalt prior to or during the application of microwave energy may increase the ability for the asphalt later to absorb the applied energy.
In some embodiments and with reference to
The microwave application system 700 may also include an irrigation subsystem 710 configured to apply moisture to the ground (asphalt) G prior to or during application of microwave energy by the plurality microwave applicator cells 701. The irrigation sub-system 710 may be variously embodied to provide a fluid such as water to the ground G. As briefly described above, the addition of water to the ground increases the dielectric loss of the ground G resulting in a more efficient transfer of microwave energy. In the embodiment of
In some embodiments, the microwave application system 700 further includes at least one surface treatment device 725 that physically alters the ground G prior to application of moisture by the irrigation subsystem 710 allowing fluid applied by the subsystem 710 to penetrate deeper into the ground. The surface treatment device 725 may be variously embodied but is configured to mechanically cut, drill, scrape, or otherwise create surface defects/channels/cracks 726 (surface modifications) that accept applied fluid. Applied fluid is able to fill the surface modifications and aid in the transfer of microwave energy to the ground G. In some further embodiments, the at least one surface treatment device 725 is a blade system configured to scarify surface modifications 726 into the ground G. Thus, the microwave application system 700 traveling in a direction 755, first creates a rough texture to the ground G, e.g. surface modifications 726, applies a fluid to the textured ground surface, and then treats the fluid enhanced textured ground 727 with microwave energy using a plurality of microwave applicator cells 701.
The amount of microwave energy applied to the ground/asphalt is dependent on the power and arrangement of each microwave generator on the system. The total energy applied is also dependent on the duration of time each microwave applicator cell is allowed to direct microwave energy to the ground. For example, if a microwave application system is configured to raise the temperature of the ground to a certain temperature, e.g., 300 degrees Fahrenheit, a single microwave cell may be placed in a single location with respect to the ground G, until the area covered by the applicator cell reaches the desired temperature. However, since the system 700 includes multiple microwave applicator cells 701, the system may apply microwave energy the ground G while advancing in a direction 755. The speed of the system in the direction of travel 755 for raising the temperature of the material G to a desired temperature is generally based on the number of microwave applicator cells 701 arranged in the direction of travel 755. For example, if a single microwave applicator cell 701 having a length dimension of two feet needs six minutes to heat an area of ground G to a desired temperature, two cells 701 arranged along the direction of travel 755, may continuously apply microwave energy while traveling in the direction of travel 755 by four (4) feet in three (3) minutes. If the application system 701 includes three (3) applicator cells 701 in the direction of travel 755, then the microwave application system 700 may move a total of six (6) feet in two (2) minutes while applying the same amount of microwave energy to the ground to obtain the desired ground temperature. It is to be appreciated that any number of microwave applicator cells 701 may be placed in the direction of travel as to allow the system 700 to move at a faster (desired) speed.
In some embodiments and with continued reference to
At the distal end 805 of each waveguide 804a-g is a microwave generator 802, (illustrated with respect to waveguide 804c) each configured to direct microwaves into its associated waveguide 804a-g and into to the asphalt layer 880. In some embodiments, the microwave generators 802 are a 1000 w, 2.45 GHz magnetron source, similar to commercially available microwave oven magnetrons. It is to be appreciated that the wattage of each microwave generator is not limiting and the wattage of each microwave generator may range from about 500 W to about 2000 w. In some embodiments, microwave energy is applied by each microwave generator 802 and waveguide 804 pair to an asphalt layer 880 such that the average temperature of the asphalt layer 880 under the applicator cell 800 is from about 220 degrees Fahrenheit to about 350 degrees Fahrenheit, including about 300 degrees Fahrenheit.
Simulations of the microwave applicator cell 800 illustrated in
In another simulation of the microwave applicator cell 800 of
The present disclosure is further illustrated in the following non-limiting working examples, it is being understood that these examples are intended to be illustrative only and that the disclosure is not intended to be limited to the materials, conditions, process parameters and the like recited herein.
A simulation was performed in COMSOL Multiphysics of a microwave applicator cell 800 configuration having a diameter D of about 20 inches, a height H of about three (3) inches, and a waveguide pattern radius R of about seven (7) inches.
After about 300 seconds of microwave application, the maximum temperature reached in the asphalt layer is about 276 degrees Fahrenheit. This max. temperature was absorbed in a small center region 1201 and the adjacent side lobes 1202. The surrounding region reached a temperature between about 120 degrees Fahrenheit and 200 degrees Fahrenheit. These results were obtained from modeling the asphalt layer 880 with a dielectric loss of 0.2.
As noted briefly above, the value for dielectric loss for asphalt is strongly influenced by moisture content. Simulation results show an improvement of energy absorption when the asphalt layer was modeled with a dielectric loss higher than 0.2. As a result of an increased dielectric loss, the asphalt layer 880 is able to absorb a greater percentage of the applied energy as indicated in the results of the Table of
The microwave applicator cell 1500 includes a center positioned waveguide 1504a, configured to direct microwave energy to the asphalt layer 880 within the first central chamber 1512 defined within the interior sidewall 1502. A plurality of radial microwave applicators 1504b are placed in a spaced apart manner and radially from the center waveguide 1504a. These radial microwave applicators 1504b are configured to direct microwave energy to the asphalt layer 880 in an area between the interior sidewall 1502 and exterior sidewall 1503.
In some further embodiments and as illustrated in
In some embodiments, the microwave applicator cell 1500 includes one central application chamber and at least three peripheral cells of equal area. In some further embodiments, and as illustrated in the exemplary embodiment of
The separator walls 1505, like the interior sidewall 1502 and exterior sidewalls 1503 may be made of a metal material. Examples of suitable metal materials include, but are not limited to, stainless steel, steel, aluminum, nickel, brass, and alloys. In some further embodiments, the sidewalls and separator walls are ⅛ inch thick stainless steel plates which are welded seamlessly together to form the applicator cell 1500. In other embodiments, the sidewalls and separator walls are cast of a metal material.
The waveguides 1504a and 1504b may be placed anywhere within an associated chamber 1512, 1513. However, in some embodiments, each waveguide 1504a, 1504b is placed such that each feed is centralized in relation to its associated chamber. As microwaves generated by the microwave generators and transmitted through the waveguides 1504a,b do not pass through metal (such as the separator walls and sidewalls), the multi-chamber microwave applicator cell may reduce destructive interference between the microwaves as they exit the waveguide feed and enter the interior volume of the microwave applicator cell therefore increasing the amount of energy absorbed. The inclusion of the separator walls also reduces the likelihood of electrical arcing within the applicator volume.
In accordance with one aspect of the present disclosure, a microwave applicator cell for providing microwave energy to a treatment surface is described. The microwave applicator cell includes an applicator body having an exterior sidewall and top wall and at least two microwave generator and waveguide pairs. Each waveguide of the microwave generator and waveguide pairs has a first end operatively connected to an associated microwave generator and a second end mounted to the top wall arranged to direct microwaves from the microwave generator to the treatment surface bounded by the applicator body. In a further embodiment, the generated microwaves have a frequency of 2.45 GHz. In another further embodiment, the exterior sidewall comprises a plurality of adjacent polygonal perimeter sections connected together to create a regular polygon shape. In another further embodiment, the applicator body is in the shape of a regular polygon as viewed from the top. In another further embodiment, one microwave generator and waveguide pair is a central microwave generator and central waveguide pair, the central waveguide is mounted to a center point of the top wall. In another further embodiment, the microwave applicator cell includes at least three spaced apart radial microwave generator and radial waveguide pairs, each mounted to the top wall and spaced apart from the central microwave generator and waveguide pair by a radius. In another further embodiment, the radius ranges from about four (4) inches to about eight (8) inches. In another further embodiment, the applicator body has a diameter from about 18 inches to about 26 inches. In another further embodiment, the applicator body has a height from about one (1) inch to about seven (7) inches. In another further embodiment, the microwave applicator cell further includes an interior sidewall spaced apart and substantially concentric with the exterior sidewall, the interior sidewall defining a central chamber, wherein at least one microwave generator and waveguide pair is configured to direct microwave energy into the central chamber toward the treatment surface. In another further embodiment, at least one microwave generator and waveguide pair is mounted such that the waveguide directs microwave energy to the treatment surface between the interior sidewall and exterior sidewall. In another further embodiment, the microwave applicator cell further includes a plurality of spaced apart separating sidewalls. Each separating sidewall extends perpendicularly from the interior sidewall to the exterior sidewall and defining at least two equally dimensioned peripheral chambers, wherein at least one (1) microwave generator and waveguide pair is configured to direct microwave energy into an associated peripheral chamber and toward the treatment surface. In another further embodiment, the interior sidewall is geometrically similar in shape to the exterior sidewall.
In accordance with another aspect of the present disclosure, a microwave application system for continuous treatment of a treatment surface is described. The microwave application system includes a plurality of microwave applicator cells for providing microwave energy to a treatment surface. Each microwave applicator cell includes an applicator body including an exterior sidewall a top wall and at least one microwave generator and waveguide pair, wherein the waveguide of the microwave generator and waveguide pair has a first end operatively connected to an associated microwave generator and a second end mounted to the top wall arranged to direct microwaves from the microwave generator to the treatment surface bounded by the applicator body. The system also includes a power source configured to supply power to the at least one microwave generator. In a further embodiment, the plurality of microwave applicator cells are arranged in a tessellation, the tessellation having a width and a length. In a further embodiment, the width of the tessellation of microwave applicator cells is about the width of a single lane road. In a further embodiment, the system further includes a central computer system in communication with the power source and each microwave applicator cell in the plurality of microwave applicator cells configured to control the generation of microwaves by the at least one microwave generator. In a further embodiment, the system further includes at least one sensor configured to detect a condition of a road surface. In a further embodiment, the at least one sensor is in communication with a central computer system, wherein the central computer system generates location data based on a sensor data of a present road condition and selectively operates a corresponding microwave applicator cell based on the location data. In a further embodiment, the system further includes an irrigation sub-system, including a fluid source and at least one spray jet configured to apply a fluid to the treatment surface prior to application of microwaves by the plurality microwave applicator cells. In a further embodiment, the system further includes at least one surface treatment device configured to physically alter the treatment surface prior to the application of microwaves by the plurality microwave applicator cells.
In accordance with another aspect of the present disclosure, a method for microwave treating a treatment surface is described. The method includes continuously advancing a plurality of microwave applicator cells, each microwave applicator cell comprising an applicator body including a sidewall a top wall and at least one microwave generator and waveguide pair, wherein the waveguide of the microwave generator and waveguide pair has a first end operatively connected to an associated microwave generator and a second end mounted to the top wall arranged to direct microwaves from the microwave generator to the treatment surface bounded by the applicator body. The method also includes applying microwaves to the treatment surface as the plurality of microwave applicator cells are continuously advancing. In a further embodiment, the method further includes spraying a fluid to the treatment surface prior to applying microwaves. In another further embodiment, the method includes mechanically modifying the treatment surface with a surface treatment device prior to spraying a fluid to the treatment surface, the surface modifications receiving the fluid prior to applying microwaves.
Although specific terms are used in the above description, for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.
The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
Numerical values in the specification and claims of this application should be understood to include numerical values which are the same when reduced to the same number of significant figures and numerical values which differ from the stated value by less than the experimental error of conventional measurement technique of the type described in the present application to determine the value.
All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of “from 2 grams to 10 grams” is inclusive of the endpoints, 2 grams and 10 grams, and all the intermediate values).
The terms “about” and “approximately” can be used to include any numerical value that can vary without changing the basic function of that value. When used with a range, “about” and “approximately” also disclose the range defined by the absolute values of the two endpoints, e.g. “about 2 to about 4” also discloses the range “from 2 to 4.” Generally, the terms “about” and “approximately” may refer to plus or minus 10% of the indicated number.
As used in the specification and in the claims, the term “comprising” may include the embodiments “consisting of” and “consisting essentially of.” The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named ingredients/components/steps and permit the presence of other ingredients/components/steps. However, such description should be construed as also describing compositions, articles, or processes as “consisting of” and “consisting essentially of” the enumerated ingredients/components/steps, which allows the presence of only the named ingredients/components/steps, along with any impurities that might result therefrom, and excludes other ingredients/components/steps.
As used herein, the terms “generally” and “substantially” are intended to encompass structural or numerical modifications which do not significantly affect the purpose of the element or number modified by such term.
The exemplary embodiments have been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
To aid the Patent Office and any readers of this application and any resulting patent in interpreting the claims appended hereto, applicants do not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.
This application claims priority benefit of U.S. Provisional Patent Application Ser. No. 67/978,041 filed Feb. 18, 2020, entitled “MICROWAVE CELL SYSTEM AND METHOD FOR ASPHALT TREATMENT,” the complete disclosure of which is herein incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/018448 | 2/18/2021 | WO |
Number | Date | Country | |
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62978041 | Feb 2020 | US |