Patent Application
20240229804
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The patent owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This disclosure relates to gas compressors, and more specifically to supersonic compressors.
A continuing interest and need exists for improvements in gas compressors. In one currently important application, a need exists for improved compressors for the compression of carbon dioxide. It would be especially advantageous if a design with significant improvement in efficiency were made available, so that operational costs of carbon capture projects utilizing carbon dioxide gas compression could be reduced.
In general, compression of gasses in radial flow compressors or in axial flow compressors is based on the exchange of kinetic energy of the gas to be compressed to potential energy represented by pressure attained in the compressor. In the case of an axial flow compressor, kinetic energy is typically imparted to the gas with rotating components including rotor blades. Then this kinetic energy is converted to potential energy in the form of pressure, usually by use of a downstream stationary component, typically referred to as a stator blade. The greater the speed of the rotor, the more kinetic energy is imparted and, in general, the greater the pressure ratio achieved by a rotor-stator pair. In the case of a radial compressor, kinetic energy is imparted to the working fluid at the leading edge of the vanes of the inducer and then a combination of inducer rotating speed and increasing radius with attendant centripetal forces, results in an increase in the pressure of the working fluid.
It is well known that aerodynamic losses increase as the speed of the rotating element (rotor in the case of an axial compression stage or inducer in the case of a radial compressor) increases. It is the speed of the rotating component which is responsible for imparting the kinetic energy to the working fluid and therefore determinant of the pressure ratio of the stage (kinetic energy is converted into potential energy in the form of pressure increase in the working fluid). Thus, the greater the speed of the rotor, the greater the kinetic energy imparted to the working fluid and the greater the possible pressure ratio of the stage. But because of the increase in aerodynamic losses attendant with increasing rotor speed, there is a tradeoff between the available pressure ratio that a single rotor/stator pair can deliver, and the efficiency of the compressor.
A rotor-stator pair (in the case of an axial flow compressor), or a single radial inducer (in the case of a radial flow compressor), may be referred to as a compression stage. Many industrial compression applications, as well as aerospace compression applications, may require multiple compressor stages in order to achieve an overall compressor pressure ratio design objective. Thus, a key factor in the design of any compressor is the determination of the number of compressor stages that will be required to achieve the compressor pressure ratio design objective. Overall capacity, as well as cost considerations, favors minimizing the number of compressor stages. And, increasing the pressure ratio in various stages becomes problematic with regard to compressor efficiency. Thus, the above mentioned tradeoff between capital cost and operating cost (i.e. compressor efficiency) is always under scrutiny. Because of the consumption of power required to drive compressors, and the cost of supplying that power, compressor efficiency is often the dominant factor under consideration during design. For compressor systems that require overall pressure ratios (“PR”) of about three (3), and certainly if over about five (5), prior art compressor designs are usually configured to employ multiple stages. Such design considerations become more acute in compression of higher molecular weight gases, such as those set out in Table 1. Table 1 additionally shows the speed of sound “a” in such gases.
One aerodynamic parameter considered during compressor design is the velocity of a leading edge of a rotor or inducer with respect to the working fluid. When the rotor or inducer velocity in the working fluid exceeds about zero point eight five Mach (M>0.85), aerodynamic shock waves begin to develop on the surfaces of the blade or vane, at a location downstream of the leading edge. Such shock waves may produce unacceptable levels of aerodynamic loss. Consequently, in most prior art compressor designs, the design velocity of the rotating blades are configured so that the relative Mach number of the blade (or vane) leading edges remain below about zero point eight five Mach (M<0.85). Such prior art designs are usually referred to as a subsonic or in some cases transonic blade design.
It is known that there is considerable potential savings, or increases in compressor efficiency, by increasing the relative Mach number of the blade leading edges into the supersonic range, where the Mach number is greater than one (M>1), which would allow the use of designs with fewer stages. Unfortunately in existing prior art compressor designs which have attempted operation at such Mach numbers, the aerodynamic losses are unacceptably high, and such loses outweigh the advantages provided by use of a decreased number of stages.
There have been various theoretical designs suggested, and experimental designs attempted, to address these and related problems, but to date, it appears that none of the designs suggested or attempted have enabled implementation of a compressor design that enables the compressor to take advantage of fully supersonic internal flow without suffering from unacceptable levels of aerodynamic loss. Moreover, most prior art supersonic compressor designs that have suffered from difficulty in “starting” a supersonic flow within the rotor blades. Such a “start” process is sometimes referred to as shock swallowing, which is a process by which an internal shockwave is developed, and then transits through a minimum area throat, to reach and become stabilized at a suitable location for highly efficient supersonic compression, at a design supersonic operating condition.
Additionally, the theoretical designs suggested, and experimental designs attempted for supersonic compressors have had only a limited “turndown” ability, in that they are unable to appreciably vary mass flow while maintaining output pressure or while minimizing the loss of efficiency. Unfortunately, it is often the case in the design of industrial compressors for process gas applications that the mass flow of working fluid will vary with time for any given application. Thus, in order for a supersonic compressor design to qualify for use in various applications, or even in application of a single gas which may vary in quantity, and/or pressure, and/or temperature, a desirable compressor design should be capable of accommodating a design variation in mass flow (for many applications, a part load mass throughput of about sixty to seventy percent (60%-70%) of full load capacity, would be desirable. And, it would be desirable to maintain discharge pressure under such turndown conditions with a minimal decrease in compression process overall efficiency.
Additionally, while there have been many attempts by others to provide improved supersonic gas compressors, most versions of which I am aware have fallen flat when it came to operability and reliability. At best, currently available gas compressor designs are primarily useful within the confines of a constant temperature and pressure gas input, since off-design conditions results in supersonic shock locations at positions which don't enable optimum efficiency, or in worst case situations, result in the inability to provide adequate starting capability, or control of boundary layer effects during operation. Consequently, there remains a need for an improved supersonic compressor design which provides easy operational adjustment for startup, and for optimization of efficiency during operation. Such a design would improve compressor flexibility with regard to varying input conditions, and increase reliability while reducing operating costs to the user.
Thus, it would be desirable if a supersonic compressor was available that included design components which made operational adjustments for starting and for efficient operation feasible within high speed rotating equipment. Such improved features would facilitate simple adjustments to accommodate changes in working fluid composition, pressure, and temperature, and thus would be advantageous in maintaining efficient supersonic compressor operation.
In prior art supersonic compressor designs, the flow path provided on a rotors have generally provided a stationary shock generating structure, and in some cases, have additionally provided a boundary layer bleed system. However, in actual practice, the location of a normal shock in a selected working fluid resulting from such fixed structures may vary depending on the density, as affected by the pressure, and temperature of the working fluid. Thus, fixed geometry for structures encountering supersonic gas flow in rotating compressor components presents the problems of (a) difficulty (or inability) to start a supersonic compressor component, and (b) inefficiency in operation, when shocks generated in the supersonic compressor components are not located to take maximum advantage of the generation of a supersonic shockwave.
Thus, the technical problem to be solved is how to provide a design for a rotor in which adjustment of shock generating structures in supersonic compression passageways is provided, to facilitate startup of the supersonic compressor, and to enable optimization of shock location, for maximizing efficiency, while the rotor is operating at high speed.
The invention(s) disclosed herein are provided to solve the above mentioned problems.
Accordingly, one objective of my invention is to provide a supersonic compressor design which is simple, straightforward, and in which an adjustably locatable shock generating body is provided in the supersonic compression passageways of rotating components in a compressor.
Another objective of my invention is to provide a design for an adjustably locatable shock generating body in the supersonic compression passageways, where the shock generating body can be adjusted to any one of multiple locations along a helical arc length L, so that the shock generating body position may be adjusted to facilitate (a) swallowing an initial shock and assuring supersonic operation startup of the compressor, or (b) efficient ongoing operation of the compressor, or (c) meets changing operational requirements, such as change in mass flow rate, or pressure, and/or temperature of a working fluid.
A related and important objective is to provide operational controls in a compressor system, which advantageously utilizes adjustments in the adjustably locatable shock generating body in the supersonic compression passageways, so that increased rotational speed may be utilized to maintain a desired output pressure, while minimizing loss in efficiency, during turndown of mass flow rates as low as the range of sixty to seventy percent (60%-70%) of rated design capacity of the compressor system.
A supersonic gas compressor is provided with an adjustably locatable shock generating body in supersonic compression passageways. In an embodiment, the gas compressor includes (a) a pressure case having a peripheral wall, (b) an inlet for supply of gas and an outlet for compressed gas, (c) a first drive shaft extending along a first central axis, (d) a first rotor, and (e) a second rotor. The first rotor is driven by the first drive shaft for rotary motion in a first direction within the pressure case. In an embodiment, the first rotor includes a plurality of impulse blades. In an embodiment, the impulse blades are unshrouded. The second rotor is driven by the first drive shaft for rotary motion in a second direction within the pressure case. The second direction is opposite in rotation from the first direction, so that the compressor is configured for counter-rotating operation. In an embodiment, the second rotor includes (1) a fixed second rotor portion having a plurality of converging-diverging passageways configured for supersonic compression of gas. The passageways have an inlet with an initial shock wave generating surface, a throat portion, and an exit. The passageways have a longitudinal axis, wherein the longitudinal axis is offset toward the first rotor by an angle of attack alpha (α). The second rotor also includes an adjustable second rotor portion. There is a geared interface between the fixed second rotor portion and the adjustable second rotor portion. The adjustable second rotor portion includes a shockwave generating body extending outward from the adjustable second rotor portion into each of the passageways in the fixed second rotor portion. The throat portion has a variable cross-sectional area, as facilitated by the adjustably positionable shockwave generating body extending from the adjustable second rotor portion. In an embodiment, the adjustable second rotor portion may include an annular outer edge, and each shockwave generating body may be affixed to the annular outer edge.
In an embodiment, each shockwave generating body may be translatable via the geared interface to provide simultaneous axial and circumferential motion of the shockwave generating body relative to the first drive shaft. Such movement of each shockwave generating body provides movement of each body in a direction parallel to or along a longitudinal axis of the passageway in which it is located. In an embodiment, the shockwave generating body may be provided in a generally diamond shaped configuration, and thus the upstream or downstream movement of the shockwave generating body provides an increase or decrease in the cross-sectional area of the throat portion of the passageway. In an embodiment, the shockwave generating body may be a centerbody. In an embodiment, the shockwave generating body may be a diamond shaped centerbody.
The increase or decrease in the cross-sectional area of the throat portion, provided by the movement of the shockwave generating body, enables both ease of startup, and efficient supersonic gas compression operation of the converging-diverging passageways, especially under changing conditions, as facilitated by the adjustment of the position of the shockwave generating body therein.
In an embodiment, the passageways include a radially inward floor at radius R from the first central axis. In an embodiment, the adjustable second rotor portion is adjustable with respect to the fixed second rotor portion to locations having a position within by a circumferential angle theta (e), so that the shockwave generating body is translatable for an arc distance of length L. In an embodiment, the adjustable second rotor portion is configured for axial movement away from the fixed second rotor portion by an axial distance X. Thus, in various embodiments, the shock generating body in each passageway may be translatable upstream or downstream along a flowpath centerline of the passageway in which it is located. In various embodiments, the shock generating body in each passageway may be translatable upstream or downstream along a helical path relative to the first central axis.
In various embodiments, one or more of the passageways may further comprise a peripheral shroud. In an embodiment, each of the passageways may further comprise a peripheral shroud. In an embodiment, the peripheral shroud may be provided in the form of a thin cylindrical annular ring, in which the cylindrical annular ring peripherally encompasses all of the passageways on the second rotor.
The present invention(s) will be described by way of exemplary embodiments, using for illustration the accompanying drawing in which like reference numerals denote like elements, and in which:
The foregoing figures, being merely exemplary, contain various elements that may be present or omitted from a final configuration for a supersonic gas compressor. Other variations in the construction of an exemplary supersonic compressor may use different materials of construction, varying mechanical structures, mechanical arrangements, gas flow configurations, or adjustment mechanism configurations, or gear drive configurations, and yet employ the basic adjustment principles described and claimed herein, and as generally depicted in the drawing figures provided. An attempt has been made to draw the figures in a way that illustrates at least those elements that are significant for an understanding of exemplary supersonic compressor designs. Such details may be quite useful for providing a novel supersonic compressor system for use in various gas compression applications. Thus, it should be understood that various features may be utilized in accord with the teachings hereof, as may be useful in different supersonic compressor rotor embodiments for use with a supersonic compressor for various capacity and working fluids, depending upon specific design requirements, within the scope and coverage of the teachings herein as defined by the claims.
Attention is directed to
In
An exemplary overall structure for an embodiment of a supersonic gas compressor 60 may be appreciated from
As also seen in
A shockwave generating body 110 extends outward from the adjustable second rotor portion 88 into each of the fixed second rotor portion passageways 90. Each shockwave generating body 110 is translatable, i.e. can move back and forth. In an embodiment, movement of each shockwave generating body 110 may be as driven, preferably with precision, by use of a geared interface 112 (see
In
As noted above, in an embodiment, the impulse blades 34 on first rotor 30 may be unshrouded. However, in an embodiment, each of the passageways 90 may include a peripheral shroud 40. As seen in
As seen in
Turning now to
In various embodiments, a helical adjuster may be provided to adjustably secure helical adjustments between the fixed second rotor portion 86 and the adjustable second rotor portion 88, as described herein. In various embodiments, helical adjustments may be provided using a geared interface 112, which may include using at least one component including helical grooves and ball bearings as described above. In various embodiments, a geared interface 112 may be provided using at least one component including use of a helical spline. In various embodiments, a geared interface 112 may be provided using at least one component including use of a worm gear. In various embodiments, a geared interface 112 may be provided using at least one component including use of a guide slot with cam follower. In any event, means for axial and circumferential adjustment between the fixed second rotor portion 86 and the adjustable second rotor portion 88 as workable to facilitate provision of an arcuately translatable shockwave generating body 110 are necessary to obtain maximum benefit of the compressor design disclosed herein.
As further evident in
An embodiment for a workable oil system configuration is suggested in
As noted above, in an embodiment, a compression spring 152 may be provided, configured to urge the adjustable second rotor portion 88 axially away from the fixed second rotor portion 86 when pressure of oil 158 in the oil gallery 170 is insufficient to urge the adjustable second rotor portion 88 toward the fixed second rotor portion 86.
The use of boundary layer bleed structures may be appreciated by reference to
As noted above, in various embodiments, the shockwave generating bodies 110 are translatable to a downstream position during startup of compressor operation, enlarge the cross-sectional area at the throat 102, as seen in
In an embodiment, a pressure case 62 for a compressor 60 as described herein may be provided in a structure adapted to contain fluids therein at an operating pressure of up to one hundred fifty (150) bar (15000 kilopascals). In an embodiment, the pressure case 62 may be provided in a structure adapted to contain a working fluid therein while operating at a pressure ratio of between about six (6) and about twenty (20). In an embodiment, a compressor 60 as described herein may be provided having an adiabatic efficiency in a range of between about zero point eight nine (0.89) at a pressure ratio of about six (6), and about zero point eight four (0.84) at a pressure ratio of about twenty (20).
Attention is directed to
For actual operation, as depicted in
indicates data missing or illegible when filed
In various embodiments, a gearbox 206 may be configured with prime mover 210 such as an electric motor including adjustable speed drive. In an embodiment, the adjustable speed drive may be operably configured to drive a rotor assembly, which includes the first rotor and the second rotor, at varying rotating speeds. In an embodiment, the method of operation at varying rotating speeds include a nominal design speed, and a part load operating speed, and in which the part load operating speed is in excess of the nominal design speed. This technique allows increased operational efficiency at part load operation, as can be seen in
Utilizing the compressor design(s) taught herein, an efficient method of continuously compressing a gas may be achieved. In such embodiments, a gas compressor as set forth herein is provided. Gas to be compressed (reference point (1) in
The advantages provided by the compressor design(s) disclosed herein are readily apparent from
The compressor design(s) provided herein are suitable, and would be advantageous, for a wide range of applications in the areas of power generation, flight propulsion, and general process gas compression. Moreover, the compressor design(s) disclosed herein are particularly well suited for an emerging application which has important implications in the area of carbon capture and sequestration (CCS) as may be more widely employed to address global climate change. In CCS, carbon dioxide (CO2) gas is separated from a pollutant stream, or perhaps by direct removal from the atmosphere. The processes by which the CO2 is separated are typically near atmospheric pressure (generally under about 5 bar (500 kPa)). The leading approach for storing or “sequestering” the CO2, once it has been separated, involves transporting it in pipelines and then pumping it into impermeable “gas tight” subterranean chambers including depleted oil and natural gas wells.
For pipeline transportation and for subterranean injection, the CO2 must be compressed to an elevated pressure (typically at least 100 bar (10000 kPa). Due to the relatively high molecular weight carbon dioxide, and low speed of sound in carbon dioxide, as summarized in Table 1, the compression of the CO2 stream is a demanding and expensive process requiring multi-stage industrial process gas compressors. Based on studies performed by the US Department of Energy (DOE) and the National Energy Technology Laboratory (NETL), the cost of compressing the CO2 stream would represent approximately 20% of the overall cost of the CCS process. Thus, when employed in a CCS application, the compressor disclosed and claimed herein would have the potential to significantly decrease the overall cost of CCS.
While my compressor would be advantageous if applied to a range of applications in many fields where the compression of a gas is required, for the purposes of introducing, illustrating and discussing the key features of the system, a design for a typical notional CCS application will be used as a reference case.
For understanding of the compressor design(s) disclosed above, as applied to carbon dioxide compression, consider a CO2 gas compressor with a required overall compression pressure ratio of one hundred to one (100:1). As an example, a typical application might have a suction pressure of about fifteen pounds per square inch (15 psia), and a discharge pressure of about fifteen hundred pounds per square inch (1500 psia), with a design mass flow of rate of fifty pounds mass of carbon dioxide per second (50 lbm/s). For such an application, a two stage version of the exemplary supersonic compressor configuration, as shown in
With respect to an exemplary compressor 60 design for compression of carbon dioxide, as just discussed above, see
In one aspect, the design disclosed herein provides impulse blades 34 on the first rotor 30, where such blades do not achieve any significant increase in static pressure. Blades 34 are intended only to impart a tangential velocity component, or swirl, to the flow immediately upstream of the passageways 90 provided in the shock compression rotor 32. Because the impulse blades 34 impart virtually no static pressure rise, tip leakage is not a significant factor for such blades 34, and thus, such blades may be operated completely open or un-shrouded. However, the impulse blades may be advantageously operated at a relative Mach number is completely subsonic over the entire span of the blade (hub to tip) with a suggested maximum Mach number of about zero point eight five (0.85). Such a design range should avoid any complications in the aerodynamic starting of rotor 30 with impulse blades 34.
The novel provision of on-rotor (e.g. as noted above for second rotor 32) variable geometry control for the passageways 90 of the shock compression rotor 32 are a significant advance in the art of supersonic gas compression. To take advantage of such variable geometry functionality, the shape of the internals of passageways 90 are important to understand. The shape of each passageway 90 includes a series of largely planar surfaces on the side walls of the internal portion of the flowpath, as described in connection with
The oblique shock waves (91, and OS2, OS3, and OS4 in
A challenge in the operation of a supersonic shock compression system as just discussed arises when the system is being brought up to speed or “started”. The amount of internal contraction that is required to efficiently decelerate the internal flow to a low pre-normal shock Mach number increases significantly as the inflow Mach number increases. As a result, a passage optimized for operation with in inflow Mach number of approximately two point three six (M ˜2.36), would have too much contraction for operation at any inlet Mach number less than that Mach number. The result of such over contraction is that the inlets 901 to passageways 90 would not be able to pass all the mass flow that the inlet 901 would capture. As a consequence, the supersonic passageways 90 would remain in an “un-started” condition.
The present design overcomes this “startup problem” in two ways. First, the variable geometry provided by the movement of centerbody 110D allows for increased area for mass flow though the throat 102. Second, removal of a portion of the working fluid is provided by various bleed passageways, as described above. In summary, the exemplary shock compression rotor in the supersonic compressor design disclosed herein utilizes both bleed of mass flow, and variable throat 102 area to facilitate starting.
The ability to translate the centerbody 110D upstream and downstream while the shock compression rotor 32 is in operation provides the capability of varying the effective contraction ratio of the shock compression passageway 90 to respond to variations in passage inflow Mach numbers that could result from variations in rotor operating speed, inflow gas composition, temperatures or a range of other parameters that could have an effect on the passageway 90 inflow Mach number.
Additionally, suction (inlet) throttling combined with variable drive speed enables high efficiency while accommodating turndown on mass flow throughput. In this novel method of compressor operation, a throttle valve 220 is incorporated upstream of the compressor 60 low pressure inlet 66. This configuration is shown in the process flow diagram, set out in
In order to restore the discharge pressure to the nominal design discharge pressure, the rotary speed of the compressor is increased by increasing the rotary speed of first input shaft 74 (when one stage gas compressor 60 is utilized) and additionally the rotary speed of second input shaft 274 when a second stage 60HP is utilized. As an example, for the exemplary carbon dioxide compressor, at 30% turndown range, the combination of a 27% decrease in compressor inflow pressure (which is accomplished by the throttle valve 220 on the compressor inflow) and a 10% increase in compressor first input shaft 74 speed, can achieve the targeted 30% turndown level while maintaining compressor discharge pressure. Further, since the changes in angle of attack at the leading edges of the shock compression rotor vanes is relatively minor, the decrease in compressor efficiency may also be minor (i.e. achieving compressor adiabatic efficiency in the 85% to 86% range at 30% turndown). Many industrial compressors employ some form of a variable speed motor drive, or variable geometry devices, to accomplish the initial starting of a compressor. Consequently, the novel method just described, with minimal increase in system cost, is clearly superior to the prior art industry standard practice of employing relatively expensive variable position inlet guide vanes.
Moreover, the compressor system described herein is still able to accommodate the use of a hot gas bypass recycling technique, should starting process or operating scenarios be encountered that involve reduced mass flow levels below what can be accomplished with the inlet throttle operation just described above. In such cases, as seen in
In the foregoing description, for purposes of explanation, numerous details have been set forth in order to provide a thorough understanding of the disclosed exemplary embodiments for the design of a supersonic compressor with an adjustable centerbody location. However, certain of the described details may not be required in order to provide useful embodiments, or to practice selected or other disclosed embodiments. Further, for descriptive purposes, various relative terms may be used. Terms that are relative only to a point of reference are not meant to be interpreted as absolute limitations, but are instead included in the foregoing description to facilitate understanding of the various aspects of the disclosed embodiments. And, various actions or activities in any method described herein may have been described as multiple discrete activities, in turn, in a manner that is most helpful in understanding the present invention. However, the order of description should not be construed as to imply that such activities are necessarily order dependent. In particular, certain operations may not necessarily need to be performed precisely in the order of presentation. And, in different embodiments of the invention, one or more structures may be simultaneously provided, or eliminated in part or in whole while other elements may be added. Also, the reader will note that the phrase “in an embodiment” or “in one embodiment” has been used repeatedly. This phrase generally does not refer to the same embodiment; however, it may. Finally, the terms “comprising”, “having” and “including” should be considered synonymous, unless the context dictates otherwise.
It will be understood by persons skilled in the art that various elements useful for configurations of supersonic compressors for use with working fluids, and especially with heavy working fluids such as carbon dioxide, have been described herein only to an extent appropriate for such skilled persons to make and use such components in combination with supersonic compressor stages. Additional details may be worked out by those of skill in the art for a selected set of specifications, increased number of stages, compression ratio, useful life, materials of construction, and other design criteria, such as the overall efficiency when operating at either design conditions or at part load conditions.
Importantly, the aspects and embodiments described and claimed herein may be modified from those shown without materially departing from the novel teachings and advantages provided, and may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Therefore, the embodiments presented herein are to be considered in all respects as illustrative and not restrictive or limiting. As such, this disclosure is intended to cover the structures described herein and not only structural equivalents thereof, but also equivalent structures.
Although only certain specific embodiments of the present invention have been shown and described, the invention is not limited to such embodiments. Rather, the invention is to be defined by the appended claims and their equivalents when taken in combination with the description. Numerous modifications and variations are possible in light of the above teachings. Therefore, the protection afforded to this invention should be limited only by the claims set forth herein, and the legal equivalents thereof.
This application claims priority from prior U.S. Provisional Patent Application Ser. No. 63/397,312, filed Aug. 11, 2022, entitled VARIABLE GEOMETRY SUPERSONIC COMPRESSOR, the disclosure of which is incorporated herein in its entirety, including the specification, drawing, and claims, by this reference.
| Number | Date | Country | |
|---|---|---|---|
| 63397312 | Aug 2022 | US |
