Patent Grant
11894647
This document relates to coverings for metallic components, such as utility poles or guy anchor rods or direct buried tower steel. More specifically, this document relates to electrically-conductive corrosion-protective coverings for metallic components, and related methods.
The following summary is intended to introduce the reader to various aspects of the detailed description, but not to define or delimit any invention.
A covering for a metallic component is disclosed. According to some aspects, the covering includes a water-impermeable heat-shrink polymeric matrix, and a particulate carbonaceous material dispersed in the polymeric matrix.
In some examples, the particulate carbonaceous material includes or is a calcined petroleum coke, a conductive carbon black, fluid coke, single-wall carbon nanotubes, graphite, and/or a carbon fibre.
A corrosion-protected electrical assembly is disclosed. According to some aspects, the corrosion-protected electrical assembly includes a metallic component having an outer surface, and a water-impermeable, electrically-conductive, heat-shrink covering applied to at least a portion of the outer surface.
In some examples, the metallic component is a utility pole or a guy anchor rod or direct buried tower steel. The metallic component may have a buried portion, and the heat shrink covering may be applied to the buried portion.
In some examples, the covering includes a water-impermeable heat-shrink polymeric matrix, and a particulate carbonaceous material dispersed in the polymeric matrix.
A method for protecting a metallic component from corrosion is disclosed. According to some aspects, the method includes applying a heat-shrink covering to at least a portion of the metallic component. The heat shrink covering is water-impermeable and electrically-conductive. The method further includes applying heat to the heat-shrink covering to shrink the heat-shrink covering and tighten the heat-shrink covering around the metallic component.
In some examples, the method further includes burying the portion of the metallic component in the earth.
In some examples, the heat-shrink covering includes a water-impermeable heat-shrink polymeric matrix, and a particulate carbonaceous material dispersed in the polymeric matrix.
According to some aspects, a corrosion-protected electrical assembly includes a metallic component having a bottom portion and an outer surface, and a water-impermeable, electrically-conductive covering applied to the outer surface at the bottom portion. The metallic component is a utility pole or a guy anchor rod or direct buried tower steel.
In some examples, the covering includes a water-impermeable polymeric matrix, and a particulate carbonaceous material dispersed in the polymeric matrix. The water-impermeable polymeric matrix can include a thermoplastic polymer or a latex. The particulate carbonaceous material can include a calcined petroleum coke, a conductive carbon black, a calcined fluid coke, a carbon fibre, single wall carbon nanotubes, and/or graphite.
In some examples, the bottom portion of the metallic component is buried in the earth.
According to some aspects, a method for protecting a metallic component from corrosion includes applying a covering to an outer surface of the metallic component at the bottom portion of the metallic component. The metallic component is a utility pole or a guy anchor rod or direct buried tower steel. The covering is water-impermeable and electrically-conductive.
In some examples, prior to step a), the method includes at least partially burying the bottom portion of the metallic component in the earth. Step a) can include pouring a fluid into a gap around the bottom portion of the metallic component, and solidifying the fluid to form the covering.
In some examples, step a) is carried out by spraying or painting.
In some examples, prior to step a), the method includes forming the covering. Step a) can include inserting the metallic component into the covering.
According to some aspects, an electrical assembly includes a metallic component having a bottom portion that is buried in the earth, a top portion that is above the earth, and an outer surface. A water-impermeable electrically-conductive covering is applied to the outer surface at the bottom portion and is in electrical contact with the earth. The covering includes a water-impermeable polymeric matrix that protects the metallic component from corrosion, and a particulate carbonaceous material that is dispersed in the polymeric matrix and that allows for the metallic component to be electrically grounded.
In some examples, the metallic component is a utility pole. In some examples, the metallic component is a guy anchor rod. In some examples, the metallic component is direct buried tower steel.
In some examples, the outer surface includes a circumferential outer surface, a bottom surface, and a top surface, and the water-impermeable electrically-conductive covering is applied only to the circumferential outer surface. In some examples, the outer surface includes a circumferential outer surface, a bottom surface, and a top surface, and the water-impermeable electrically-conductive covering is applied to the circumferential outer surface and the bottom surface.
In some examples, the water-impermeable polymeric matrix is or includes a thermoplastic or thermoset polymer. In some examples, the water-impermeable polymeric matrix is or includes a latex. In some examples, the water-impermeable polymeric matrix is or includes a styrene butadiene latex, an acrylic latex, a styrene acrylic latex, an acrylonitrile-butadiene latex, and/or a vinyl acetate copolymer latex. In some examples, the water-impermeable polymeric matrix is or includes a fluoropolymer. In some examples, the water-impermeable polymeric matrix is or includes an ethylene vinyl acetate.
In some examples, the water-impermeable polymeric matrix is or includes a heat shrunk polymer. The heat shrunk polymer can be or can include at least one of a silicone-grafted cross-linked polyethylene, a polychloroprene, a radiation cured cross-linked polymer, and a fluoroelastomer.
In some examples, the particulate carbonaceous material is or includes a calcined petroleum coke, and/or one or more conductive carbon blacks, and/or a carbon fibre, and/or calcined fluid coke, and/or single wall carbon nanotubes, and/or graphite and/or metallurgical coke.
In some examples, the water-impermeable electrically-conductive covering has an electrical resistivity of 0.1 to 50 ohm·cm.
In some examples, the water-impermeable electrically-conductive covering has a water permeability of between 0.01 US Perms and 1.0 US Perms, or between 10−5 cm/s and 10−10 cm/s.
In some examples, the water-impermeable electrically-conductive covering is score-resistant and scratch-resistant.
In some examples, the particulate carbonaceous material makes up between 0.1 wt % and 70 wt % of the covering. In some examples, the particulate carbonaceous material makes up between 0.1 wt % and 50 wt % of the covering.
The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way. In the drawings:
Various apparatuses or processes will be described below to provide an example of an embodiment of the claimed subject matter. No embodiment described below limits any claim and any claim may cover processes or apparatuses that differ from those described below. The claims are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or process described below is not an embodiment of any exclusive right granted by issuance of this patent application. Any subject matter described below and for which an exclusive right is not granted by issuance of this patent application may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such subject matter by its disclosure in this document.
In general, disclosed herein are coverings for metallic components, such as utility poles or guy anchor rods or direct buried tower steel. The coverings can be water-impermeable, and can thus protect the metallic components from corrosion (e.g. galvanic corrosion). The coverings can also be electrically-conductive, and can thus allow the metallic components to be electrically grounded. The coverings can in some examples be pre-applied to the metallic components. For example, the coverings can be heat-shrink coverings, which can be applied to the metallic components prior to installation of the metallic components. The heat-shrink nature of the coverings can facilitate application of the coverings to the metallic components. For further example, the coverings can be applied to the metallic components by spraying or painting. In other examples, the coverings can be applied to the metallic components in-situ. For example, the components of the covering may be provided as a fluid. The fluid may be poured into a form surrounding a buried end of a metallic component (e.g. a utility pole), and may then solidify (e.g. by curing or setting). The coverings may have a substantially long service life, and they may be resistant to scoring or scratching (e.g. so that covered metallic components can be transported from a factory to an installation site without substantive damage to the coverings).
In general, the coverings disclosed herein can include a water impermeable polymeric matrix and one or more non-metallic conductive materials dispersed in the polymeric matrix. The non-metallic conductive materials may be dispersed in any suitable polymeric matrix. The covering can be applied with various application techniques.
As used herein, the term ‘heat-shrink’ can refer to a material that will shrink upon the application of heat, or to a material that has already been shrunk by the application of heat. That is, the term ‘heat-shrink covering’ can refer to a covering both before and after being shrunk by the application of heat. The term ‘heat-shrinkable’ is used herein to specifically refer to a material that will shrink upon the application of heat—i.e. the term ‘heat-shrinkable covering’ refers to a covering before being shrunk by the application of heat. The term ‘heat-shrunk’ is used herein to specifically refer to a material that has already been shrunk by the application of heat—i.e. the term ‘heat-shrunk covering’ refers to a covering after being shrunk.
As used herein, the term ‘electrically-conductive’ indicates that the covering has an electrical resistivity of less than 500 ohm·cm. For example, the covering may have an electrical resistivity of between 0.1 ohm·cm and 500 ohm·cm.
As used herein, the term ‘water-impermeable’ indicates that the covering has a water permeability of less than or equal to 1.0 US Perms, or a water permeability of less than 10−5 cm/s. For example, in the case of a covering including a heat-shrink polymeric matrix, the covering may have a water permeability of between 0.01 US Perms and 1.0 US Perms. Alternatively, in the case of a covering that is formed in-situ, for example by pouring, the covering may have a water permeability of between 10−5 cm/s and 10−10 cm/s.
As used herein, the term ‘in situ’ indicates that the metallic component has already been installed, either partially or fully, at its site of use. For example, the statement that the coverings can be applied to a utility pole in-situ indicates that the coverings can be applied to a bottom end of the utility pole after the bottom end of the utility pole is partially or fully buried in the earth. In contrast, the term ‘pre-applied’ indicates that the covering is applied to the metallic component prior to installation of the metallic component, for example at a manufacturing facility.
The metallic components covered by the coverings can be various electrical conductors, for example utility poles (e.g. steel utility poles), or guy anchor rods (e.g. for utility poles), or direct buried tower steel (e.g. a monopole or the legs of a tower).
The metallic components can be fully covered by the coverings, or partially covered by the coverings. For example, if a specific portion of the outer surface of the metallic component is in a corrosive environment (e.g. buried in the earth), the covering may be applied to that portion.
As will be described in further detail below, the covering may include a matrix that is formed from a polymer (also referred to herein as a ‘polymeric matrix’), and a particulate carbonaceous material dispersed in the matrix. The covering may optionally include various additives. The polymeric matrix may provide the covering with sufficient water impermeability to protect a metallic component from corrosion (e.g. to protect a buried end of a utility pole from galvanic corrosion), and the particulate carbonaceous material may provide the covering with sufficient electrical conductivity to, for example, allow the metallic component to be electrically grounded.
Referring now to
Referring still to
In the example shown, the covering 110 is a water-impermeable, electrically-conductive, heat-shrink covering. As discussed above, the water-impermeability of the covering 110 can protect the bottom portion 104 of the utility pole 102 from corrosion, particularly galvanic corrosion, while the electrical conductivity of the covering 110 can allow for the utility pole 102 to be electrically grounded (i.e. in electrical contact with the surrounding earth).
In the examples of
The covering 110 may be formed from a water-impermeable, heat-shrink, polymeric matrix. A particulate carbonaceous material may be dispersed in the polymeric matrix, in order to render the covering 110 electrically-conductive.
In some examples, the polymeric matrix of the covering 110 may be or may include a polyolefin such as polyethylene or polypropylene; a fluoropolymer such as polyvinylidene fluoride; an ethylene vinyl acetate; a silicone-grafted cross-linked polyethylene; a latex such as a styrene butadiene latex, an acrylic latex, a styrene acrylic latex, an acrylonitrile-butadiene latex, or a vinyl acetate copolymer latex; a flexible polyvinylchloride compound; a polychloroprene; a silicone elastomer; a fluoroelastomer and/or other elastomeric materials; or a combination thereof.
In some examples, the particulate carbonaceous material of the covering 110 may include or may be a coke, and/or graphite, and/or carbon black, and/or single wall carbon nanotubes, and/or carbon fibre. The coke may be or may include a calcined fluid coke, and/or calcined petroleum coke, and/or metallurgical coke. The calcined fluid coke may be one sold by Asbury Carbons (Asbury, N.J.) under the name 251P Calcined Fluid Coke (20×200 mesh).
In some examples, the particulate carbonaceous material may make up between 0.1 wt % and 70% of the covering, or between 0.1 wt % and 50 wt % of the covering. The remainder of the covering may be made up of the polymeric matrix, and/or additives.
In some examples, the covering may be fabricated by compounding the polymeric matrix, the particulate carbonaceous material, and any additives, then processing this material similarly to other heat-shrink materials. For example, this material may be extruded as a tube, and the tube be fully or partially cross-linked, for example by silane condensation, applying radiation, or chemically via radical polymerization. The tube may then be heated to above the polymer's crystalline melting point and expanded in diameter, for example in a vacuum chamber. The tube may then be cooled, to yield an electrically-conductive corrosion-protective heat-shrinkable covering in the form of a tube (also referred to herein as a ‘tubular heat-shrinkable covering’).
In alternative examples, the material may be extruded or formed as a sheet, rather than a tube. Coverings in the form of a sheet may be referred to herein as ‘heat-shrinkable sheet coverings’.
In some examples, the heat-shrink coverings may be lined with an electrically-conductive adhesive.
Optionally, the heat-shrink coverings may be in the form of a co-extruded system, which includes an additional layer of a hot-melt adhesive, such as suitable ethyl-vinyl acetate (EVA), or other polymeric materials such as butyl-elastomers containing similar carbonaceous materials. The carbonaceous materials can allow for continuous conductivity throughout the polymeric matrix.
The covering may be applied to the metallic component in a variety of ways. In some examples, the metallic component (e.g. the bottom portion of a utility pole) may be inserted into the tubular heat-shrinkable covering, and then heat may be applied to shrink the tubular heat-shrinkable covering and tighten the tubular heat-shrinkable covering around the metallic component. In other examples, the metallic component may be wrapped with the heat-shrinkable sheet coverings, and then heat may be applied to shrink the heat-shrinkable sheet covering and tighten the heat-shrinkable sheet covering around the metallic component. In some examples, an electrically-conductive adhesive may be applied between the covering and the metallic component. In some examples, machinery similar to that used for coating pipes with heat-shrink coatings may be used to apply the covering to the metallic component. The covered portion of the metallic component (e.g. the bottom portion of the utility pole) may optionally then be buried in the earth.
Referring to
In the example of
In the example shown in
In this example, the covering 310 can be made from a polymeric matrix that is provided as a fluid and solidifies (e.g. sets or cures) to form a water-impermeable solid. For example, the fluid polymeric matrix may be made from a latex such as a styrene butadiene latex, an acrylic latex, a styrene acrylic latex, a acrylonitrile-butadiene latex, a vinyl acetate copolymer latex, or a combination thereof. The covering 310 can further include a curing agent for the fluid polymeric matrix. The curing agent can be a cement, such as a Portland cement.
The particulate carbonaceous material of the covering 310 may be or may include a coke, and/or graphite, and/or carbon black, and/or carbon fibre, and/or carbon nanotubes. The coke may be or may include a calcined fluid coke, and/or calcined petroleum coke, and/or metallurgical coke. The calcined fluid coke may be one sold by Asbury Carbons (Asbury, N.J.) under the name 251P Calcined Fluid Coke (20×200 mesh).
In some examples, the particulate carbonaceous material may make up between 40 wt % and 90 wt % of the covering 310, or between 50 wt % and 90 wt % of the covering 310. The remainder of the covering 310 may be made up of the polymeric matrix, and/or additives (e.g. the curing agent, and/or a surfactant, and/or water, and/or propylene glycol).
The material for the covering 310, including the polymeric matrix in a fluid state, the curing agent, the water, the particulate carbonaceous material, and any other additives can be combined, and then poured into the gap 322, and then cured or allowed to set.
In an alternative example, the polymeric matrix may be made from a thermoplastic material such as polypropylene, which is heated to form a fluid, and then poured into the gap 322. Upon cooling, the thermoplastic material can set to form a solid. The thermoplastic material can optionally be cross-linked. A particulate carbonaceous material may be dispersed in the polymeric matrix when it is in its fluid state, in order to render the covering 310 electrically-conductive.
In other examples (not shown), the covering may be pre-applied and formed directly onto the metallic component by other methods, such as spraying or painting. In yet other examples, the covering may be preformed and then pre-applied to the metallic component. For example, the covering may be formed as a tube, with an interior diameter sized to snugly fit around a utility pole. Heat may be applied to the tube to soften the tube, and then the utility pole may be inserted into the tube. The tube may then cool and harden.
A material of the following composition was prepared:
A material of the following composition was prepared:
The Latex, polymerization surfactant, propylene glycol, and water were mixed, and the particulate carbonaceous material was slowly added to the mixture with ongoing mixing. This mixture was then stored in a sealed container.
When ready for use, the container was opened and the curing agent was added with additional mixing. The material was then allowed to cure. Samples of the cured material were tested for their material properties. Results are shown in tables 3 and 4:
A heat shrinkable material of the following composition was prepared using radiation curing.
The polymeric blend was mixed in a twin-screw extruder and was extruded. Extrusions in sheet form and tube form were conducted. Following extrusion, the conductive polymeric material was radiation cured using Electron Beam technology to achieve a cross-link density of 60% or more and expanded depending on form. Upon application of heat, the polymeric shape recovered to its original dimensions and formed a barrier with interfacial contact to the metal substrate with resistivity values of 0.1-50 ohm·cm.
While the above description provides examples of one or more processes or apparatuses, it will be appreciated that other processes or apparatuses may be within the scope of the accompanying claims.
To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be re-visited.
This application is a continuation of U.S. patent application Ser. No. 16/147,965 filed on Oct. 1, 2018, which claims the benefit of and/or priority from U.S. Provisional Patent Application No. 62/568,015 filed on Oct. 4, 2017, and U.S. Provisional Patent Application No. 62/703,481 filed on Jul. 26, 2018, all of which are incorporated herein by reference in their entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2196172 | Billings et al. | Jun 1837 | A |
| 1661712 | Wagner | Mar 1928 | A |
| 2495466 | Miller | Jan 1950 | A |
| 2553654 | Heise | May 1951 | A |
| 3072558 | Myers et al. | Jan 1963 | A |
| 3243753 | Fred | Mar 1966 | A |
| 3334040 | Conrad et al. | Aug 1967 | A |
| 3573427 | Minsk | Apr 1971 | A |
| 3616354 | Russell | Oct 1971 | A |
| 3716649 | Walker et al. | Feb 1973 | A |
| 3725669 | Tatum | Apr 1973 | A |
| 3725699 | Pascoe | Apr 1973 | A |
| 3876819 | Boyd et al. | Apr 1975 | A |
| 3917781 | Gabriel et al. | Nov 1975 | A |
| 3927163 | Gabriel et al. | Dec 1975 | A |
| 3941918 | Nigol et al. | Mar 1976 | A |
| 3962142 | Freeman et al. | Jun 1976 | A |
| 4017569 | Hass | Apr 1977 | A |
| 4018715 | Tatum | Apr 1977 | A |
| 4144077 | Gallus | Mar 1979 | A |
| 4170532 | Tatum | Oct 1979 | A |
| 4175021 | Tatum et al. | Nov 1979 | A |
| 4192963 | Koehmstedt | Mar 1980 | A |
| 4367168 | Kelly | Jan 1983 | A |
| 4400259 | Schutt | Aug 1983 | A |
| 4407676 | Restrepo | Oct 1983 | A |
| 4414030 | Restrepo | Nov 1983 | A |
| 4442903 | Schutt et al. | Apr 1984 | A |
| 4472468 | Tailor et al. | Sep 1984 | A |
| 4544464 | Bianchi et al. | Oct 1985 | A |
| 4710644 | Baach | Dec 1987 | A |
| 4786388 | Tatum, Jr. | Nov 1988 | A |
| 4799959 | Fourez et al. | Jan 1989 | A |
| 4818439 | Blackledge et al. | Apr 1989 | A |
| 4871395 | Sugama | Oct 1989 | A |
| 4908157 | Fontana et al. | Mar 1990 | A |
| 5026468 | Carpenter et al. | Jun 1991 | A |
| 5026508 | Tatum, Jr. et al. | Jun 1991 | A |
| 5040599 | Pfalser et al. | Aug 1991 | A |
| 5055166 | Schutt | Oct 1991 | A |
| 5070597 | Holt et al. | Dec 1991 | A |
| 5080773 | Tatum, Jr. et al. | Jan 1992 | A |
| 5098771 | Friend | Mar 1992 | A |
| 5139634 | Carpenter et al. | Aug 1992 | A |
| 5143649 | Blackledge et al. | Sep 1992 | A |
| 5167710 | Leroux et al. | Dec 1992 | A |
| 5174871 | Russell | Dec 1992 | A |
| 5207530 | Brooks et al. | May 1993 | A |
| 5254228 | Westhof et al. | Oct 1993 | A |
| 5294396 | Dressel et al. | Mar 1994 | A |
| 5370783 | Carlson et al. | Dec 1994 | A |
| 5413689 | Nora et al. | May 1995 | A |
| 5447564 | Xie et al. | Sep 1995 | A |
| 5476612 | Wessling et al. | Dec 1995 | A |
| 5507933 | Nora et al. | Apr 1996 | A |
| 5525208 | Pritula et al. | Jun 1996 | A |
| 5547311 | Kenda | Aug 1996 | A |
| 5550176 | Lewis et al. | Aug 1996 | A |
| 5609748 | Kotowski et al. | Mar 1997 | A |
| 5700398 | Angelopoulos et al. | Dec 1997 | A |
| 5753861 | Hansen et al. | May 1998 | A |
| 5908584 | Bennett | Jun 1999 | A |
| 5976419 | Hawkins et al. | Nov 1999 | A |
| 6022469 | Page | Feb 2000 | A |
| 6121543 | Hallmark | Sep 2000 | A |
| 6193443 | Trudeau et al. | Feb 2001 | B1 |
| 6193857 | Davison et al. | Feb 2001 | B1 |
| 6303017 | Page et al. | Oct 2001 | B1 |
| 6514608 | Foulger | Feb 2003 | B1 |
| 6821336 | Ramme et al. | Nov 2004 | B1 |
| 7186321 | Benham | Mar 2007 | B2 |
| 7405247 | Sachdev et al. | Jul 2008 | B2 |
| 7422789 | Avakian et al. | Sep 2008 | B2 |
| 7540776 | Graeve et al. | Jun 2009 | B2 |
| 7619161 | Okabayashi et al. | Nov 2009 | B2 |
| 7745528 | Prud'Homme et al. | Jun 2010 | B2 |
| 7794626 | Horton | Sep 2010 | B2 |
| 8081415 | Nolletti | Dec 2011 | B2 |
| 9252503 | Nolletti | Feb 2016 | B2 |
| 10109392 | Maunder et al. | Oct 2018 | B2 |
| 10280580 | Goff et al. | May 2019 | B1 |
| 10433371 | Miller | Oct 2019 | B2 |
| 11121482 | Sirola | Sep 2021 | B2 |
| 20020162484 | Ramme et al. | Nov 2002 | A1 |
| 20040099982 | Sirola et al. | May 2004 | A1 |
| 20050194576 | Sirola et al. | Sep 2005 | A1 |
| 20070187854 | Sirola et al. | Aug 2007 | A1 |
| 20080217041 | Kim | Sep 2008 | A1 |
| 20090233470 | Kim | Sep 2009 | A1 |
| 20100159148 | Hagens et al. | Jun 2010 | A1 |
| 20130048917 | Virtanen et al. | Feb 2013 | A1 |
| 20130168126 | Kuchta et al. | Jul 2013 | A1 |
| 20140251793 | Funahashi et al. | Sep 2014 | A1 |
| 20150028247 | Peters | Jan 2015 | A1 |
| 20150133593 | Kissell et al. | May 2015 | A1 |
| 20150282471 | Lampman et al. | Oct 2015 | A1 |
| 20160115293 | Aksay et al. | Apr 2016 | A1 |
| 20160163419 | Sirola et al. | Jun 2016 | A1 |
| 20190256670 | Konno | Aug 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 1424162 | Feb 1976 | GB |
| 05198321 | Aug 1993 | JP |
| 101089543 | Dec 2011 | KR |
| 1997014196 | Apr 1997 | WO |
| 1997032936 | Sep 1997 | WO |
| Entry |
|---|
| Electrically Conductive Adhesives—Henkel, https://www.henkel-adhesives.com/us/en/products/industrial-adhesives/electrically-conductive-adhesives.html. |
| Office Action issued in Canadian Patent Application No. 3019309 dated Aug. 25, 2023. |
| Number | Date | Country | |
|---|---|---|---|
| 20210384650 A1 | Dec 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62703481 | Jul 2018 | US | |
| 62568015 | Oct 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16147965 | Oct 2018 | US |
| Child | 17405404 | US |
