Patent Publication Number: US-2021169263-A1

Title: Frothing device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 16/410,521 filed on May 13, 2019, which is incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND 
     The present disclosure relates generally to a mechanism for preparing milk for espresso or cocoa-based drinks such as cappuccinos, cafe lattes, and mochas. 
     SUMMARY 
     One exemplary embodiment of the disclosed subject matter is a frothing device preferably having a handle, a rotatable shaft coupled to the handle, an impeller rotatable by the shaft, and a screen disposed about the impeller opposite the handle. The frothing device may further include a holder disposed about the impeller and the screen. The screen is preferably annular in shape. The shaft may be integral to the impeller but preferably is coupled via a threaded arrangement. 
     In another exemplary embodiment, the frothing device includes a rotatable shaft, an impeller rotatable by the shaft, and a screen disposed about the bottom of the impeller downstream of the flow of fluid being pushed by the impeller. This frothing device may also have a handle coupled to the rotatable shaft. A holder may be disposed about the impeller and the screen. 
     In the alternative to the handle arrangement, the frothing device may include a pitcher having a bottom wall, wherein the rotatable shaft extends upward from the bottom wall of the pitcher. With this configuration, the impeller preferably includes a channel configured to receive the rotatable shaft. Moreover, the frothing device may include a housing having a heater and a nub extending upwardly from the housing. The shaft has an opening at its bottom, wherein the opening of the shaft is configured to receive the nub. A holder is preferably disposed about the impeller and the screen, wherein the screen has a hole configured to receive the impeller. 
     Another exemplary embodiment of the disclosed subject matter is a method of frothing comprising creating a vortex in milk using a frothing device, wherein the frothing device includes a rotatable shaft, an impeller rotatable by the shaft, and a screen disposed about the bottom of the impeller downstream of the flow of fluid being pushed by the impeller. The vortex is then stopped, either by moving the impeller away from the center or by slowing down the rotation of the impeller, wherein the milk is churned until microfoam is generated. The rotatable shaft may be coupled to a handle. In the alternative, the frothing device may include a pitcher, wherein the rotatable shaft is disposed about the bottom wall of the pitcher. The pitcher is disposed about the housing having a heater and a nub extending from the housing, wherein the rotatable shaft is configured to receive the nub. A holder may be disposed about the impeller and the screen. 
     In another exemplary embodiment, the frothing device includes a pitcher comprised of a body having a top and an opposing bottom and an inner bowl. The inner bowl has a bottom wall disposed between the top and bottom of the pitcher body, wherein the inner bowl defines a liquid compartment and an electrical compartment within the interior of the pitcher. A lid is disposed about the top of the pitcher body. A shaft extends downward from the lid in a position offset from a central location of the lid. An impeller is disposed about a bottom end of the shaft wherein the impeller has blades and a holder disposed about the blades. A first ring is disposed about the impeller opposite the shaft. The first ring includes a first set of magnets and a screen contained by the first ring. A second ring is contained within the electrical compartment and disposed opposite the first ring. The second ring includes a second set of magnets corresponding to the combination of magnets within the first ring. A variable high speed motor rotates the second ring at different rates of speed, causing the impeller to rotate and create microfoam from milk poured into the liquid compartment of the pitcher. The pitcher sits upon a base, which provides electricity to the pitcher. The base also includes a heater for heating the milk. 
     The first set of magnets includes pairs of positive polarity magnets disposed next to pairs of negative polarity magnets. The second set of magnets includes pairs of positive polarity magnets disposed next to pairs of negative polarity magnets. The inner bowl preferably has tapered sides. The first ring is removably attachable to the holder via a tongue and groove arrangement. 
     In another exemplary embodiment, the frothing device includes a pitcher having a liquid compartment and an electrical compartment. A rotatable impeller is contained within the liquid compartment, wherein the impeller includes blades and a holder disposed about the blades. A first ring is removably coupled to the impeller wherein the first ring has a first set of magnets of positive polarity and negative polarity. The first ring further includes a screen disposed adjacent to the electrical compartment. A rotatable second ring is contained within the electrical compartment and disposed opposite the first ring. The second ring has a second set of magnets of positive and negative polarity. A rotatable shaft is disposed about a bottom of the liquid compartment offset from center, wherein the impeller is disposed about one end of the rotatable shaft. The impeller is capable of being rotated at various speeds and up to 7,000 RPM to create desired microfoam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some non-limiting exemplary embodiments of the disclosed subject matter are illustrated in the following drawings. Identical or duplicate or equivalent or similar structures, elements, or parts that appear in one or more drawings are generally labeled with the same reference numeral, optionally with an additional letter or letters to distinguish between similar objects or variants of objects, and may not be repeatedly labeled and/or described. Dimensions of components and features shown in the figures are chosen for convenience or clarity of presentation. For convenience or clarity, some elements or structures are not shown or shown only partially and/or with different perspective or from different point of views. 
         FIG. 1  is a perspective view of an exemplary embodiment disclosed herein; 
         FIG. 2  is an exploded view of certain aspects of the embodiment shown in  FIG. 1 ; 
         FIGS. 3A-3B  are perspective views showing exemplary use of the embodiment seen in  FIG. 1 ; 
         FIG. 4  is a perspective view of certain aspects of the embodiment shown in  FIG. 1  in use; 
         FIGS. 5A-6B  are perspective views of another exemplary embodiment disclosed herein; 
         FIG. 7A  is an exploded view of certain aspects of the embodiment shown in  FIGS. 5A-6B ; 
         FIGS. 7B-7C  are perspective views of certain aspects of the embodiment shown in  FIGS. 5A-6B ; 
         FIGS. 8A-8B  are perspective views of another exemplary embodiment disclosed herein; 
         FIG. 9  is a perspective view of another exemplary embodiment disclosed herein; 
         FIG. 10  is an exploded view of certain aspects of the embodiment shown in  FIG. 9 ; 
         FIG. 11A  is a perspective, sectional view of the embodiment shown in  FIG. 9 ; 
         FIG. 11B  is a cut-away view of certain aspects of the device seen in  FIG. 11A ; 
         FIGS. 12A-13A  are detailed views of certain aspects of the device seen in  FIG. 11A ; 
         FIG. 13B  is a perspective, sectional view of aspects of the device seen in  FIG. 13B ; 
         FIG. 14  is a perspective, sectional view of an alternative embodiment to that shown in  FIG. 9 ; and 
         FIGS. 15A-15D  schematically illustrate the device seen in  FIG. 9  in operation. 
     
    
    
     DETAILED DESCRIPTION 
     The preparation of quality silky textured milk for a cappuccino that allows a barista to create elegant patterns on the drink known as “latte art” is commonly seen in coffee shops. Such shops use large commercial espresso machines containing multiple water boilers, one of which is dedicated to creating scalding and high pressured steam. This steam is pushed through a steam wand at high velocity to heat the milk and create foam. A knowledgeable barista may further break down the bubbles in the foam to create even smaller bubbles, which may be referred to as microfoam. Microfoamed milk mixes with the espresso when being poured and adds a nice perceived sweetness to the final drink. 
     While it is possible for the home barista to create foam using an espresso machine having a steam boiler and wand, it is quite a different feat to create silky microfoam textured milk suitable for creating latte art. The typical home machine is just not as stout as the commercial machines found in coffee shops. Furthermore, many small home espresso machines do not include a second boiler or steam wand at all and only produce espresso, leaving the user unable to create any kind of microfoam milk. In an attempt to supplement these deficiencies, frothing devices have been designed for home use. Such devices usually employ a small whisk to create ordinarily sized bubbles, resulting in the milk almost immediately separating and having a thick foam texture on top with milk at the bottom. When poured, the milk will come out first followed by a blob of foam or “dry foam.” This dry foam blob does not mix well with the espresso drink, creates a separation of flavors with frothy milk on top and espresso on the bottom, and does not permit the desirable latte art. Moreover, for many people, this dry foam is very undesirable as it does not have that extra perceived sweetness and makes a drink that is very different to what is produced by a professional barista. 
     Accordingly, a frothing device solving these and other problems is desired. 
     A general non-limiting overview of practicing the present disclosure is presented below. The overview outlines exemplary practice of embodiments of the present disclosure, providing a constructive basis for variant and/or alternative and/or divergent embodiments, some of which are subsequently described. 
       FIGS. 1-4  illustrate one such exemplary embodiment of novel frothing device  100  disclosed herein. As seen in  FIG. 1 , the device  100  preferably includes a handle  102  coupled to a rotatable shaft  104 . The shaft  104  is in turn coupled to an impeller  106  having blades  108 . The blades  108  may be of varying dimensions and shapes depending on the amount of thrust desired to be created, as discussed below. 
     As best seen in  FIG. 2 , a mesh screen  112  is disposed about the impeller  106  opposite the shaft  104 . The sizes of the holes within screen  112  may also be of varying dimensions and shapes depending on how large or fine the user desires the final bubble sizes to be in the resultant microfoam. The screen  112  may be coupled to the impeller  106  such as via welding, co-injecting, or some arrangement less permanent. Preferably, however, the screen  112  is disposed about the impeller  106  by way of a holder  110 . 
       FIG. 2  illustrates the holder  110  may be annular in shape, wherein both the screen  112  and impeller  106  are constrained and held in place by holder  110  for added support and rigidity of the overall device  100 . 
       FIG. 2  also illustrates the shaft  104  is preferably coupled to the impeller  106  via a thread and groove arrangement. In particular, shaft  104  may have threads  116  configured to engage grooves  120  cut into a channel of the impeller  106 . 
     Turning back to  FIG. 1 , the frothing device  100  preferably includes a switch  114  in the handle  102 . The switch  114  is in electrical communication with circuitry and a power supply such as one or more batteries. The switch  114  permits the device  100  to be powered on or off, and also preferably permits the shaft  104  to be rotated at varying speeds. 
     In operation, device  100  is operated by placing hot or cold milk into a pitcher  122  or container and submerging the impeller  106  and screen  112  into the milk near the center, as illustrated by  FIG. 3A . The user may then toggle switch  114  to rotate shaft  104 . Doing so will cause the impeller  106  and screen  112  to rotate rapidly inside the milk to create a vortex. The vortex in turn mixes ambient air with the milk to make bubbles and foam. When the device  100  is moved further off-center (as seen in  FIG. 3B ), the vortex ceases, and the impeller  106  becomes entirely submerged. No longer contacting ambient air and no longer producing new foam bubbles, the impeller  106  now only churns the milk and pulls the foam down where it is pushed through the impeller  106  and screen  112 . The foam bubbles are thus broken down into microscopic bubbles  124  as they are forced through the screen  112  repeatedly, as best seen in  FIG. 4 . The result is a silky smooth microfoamed milk for pouring over espresso or the like and creating latte art if desired. 
     Thus, it is the particular configuration of the screen  112  disposed below the impeller  106 , i.e., downstream of the flow, that creates the microfoam rather than the use of steam or a whisk. Moreover, it is worth noting that such a configuration is counter-intuitive and/or opposite to what may be thought of as a conventional filter and impeller arrangement. In other words, screens or filters would typically be disposed above the impeller, i.e., upstream of the flow, to filter out unwanted material from passing into the impeller and thus irreparably damaging it. However, with the disclosed embodiments, the screen  112  is downstream of the flow—not for the purpose of filtering out any undesirable material—but rather for breaking down bubbles in the flow to create the desirable microfoam. 
       FIGS. 5A-7C  illustrate another embodiment of the disclosed subject matter. As seen therein, the frothing device  200  preferably comprises a pitcher  202  disposed about a housing  206 . The pitcher  202  includes a rotatable shaft  204  disposed about the bottom wall of the pitcher  202 , as best seen in  FIG. 5B . The shaft  204  includes a channel configured to receive a rotatable nub  290  disposed about the top wall of the housing  206 . 
     The device  200  further includes an impeller  214  having blades  216  of varying dimensions and shapes depending on user preference, as discussed above in the context of  FIGS. 1-4 . The impeller  214  is configured to engage the rotatable shaft  204 , as illustrated in  FIGS. 6A-6B .  FIG. 7A  illustrates an exploded view of an exemplary engagement obtained by a channel  218  cut into the impeller  214  for receiving the rotatable shaft  204 . Instead of this configuration, the device  200  may use a magnetic spinning arrangement to turn the impeller  214 . 
       FIG. 7A  also shows the use of a screen  222  disposed about the impeller  214  in a downstream arrangement as discussed above. Stated differently, the impeller  214  is rotatable by the shaft  204 , wherein the impeller  214  has a top and an opposing bottom. The impeller  214  is configured to move fluid from the top to the bottom of the impeller  214 , wherein the screen  222  is disposed about the bottom of the impeller  214 . 
     The screen  222  may be permanently attached to impeller  214  or removable as discussed above. Moreover, an optional holder  210  may partially encapsulate the impeller  214  and screen  222 , the latter of which preferably has a cut-out centrally located therein to receive the bottom portion of the rotatable impeller  214 , as best seen in  FIGS. 7A-7C . 
     Referring again to  FIG. 5A , the housing  206  preferably includes a heater  208  for heating milk in pitcher  202 . Switches  212  are disposed about the housing  206 . The switches  212  are in electrical communication with a power supply such one or more batteries. The switches  212  may be engaged by the user to turn on device  200 , causing heater  208  to heat up and rotating shaft  204  to spin impeller  214 . The user may use the switches  212  to vary the speed of the impeller and thus the speed at which milk flows from the top of the pitcher  202 , through the blades  216 , and then the screen  222  downstream of the flow. Doing so permits the user to create a vortex and aerate the milk or to churn and create microfoam. 
       FIGS. 8A-8B  illustrate another embodiment of the disclosed subject matter. Here, the frothing device  300  may include a pitcher  302  containing a waterproof rotatable shaft  304  disposed about the bottom of the pitcher  302 . An impeller  308 , screen, and holder  310  arrangement similar to that illustrated in  FIGS. 5A-7C  may be connected to this shaft  304  from inside the pitcher  302 . Doing so positions the impeller  308  and screen component near the bottom of the pitcher  302  and preferably slightly off-center. The device  300  also preferably includes a housing  306  having a hot plate with a motorized rotating nub. The nub is positioned to couple with the shaft  304  when the pitcher  302  is placed on the hot plate. When turned on, the hot plate heats the pitcher  302  to warm the milk and rotate the nub and blend the milk. Accelerating the impeller  308  and screen sufficiently will create a vortex in the milk while decelerating will stop the vortex and churn the milk to create the desired microfoam, as discussed above. 
       FIGS. 9-13B  illustrate another exemplary embodiment of novel frothing device  400  disclosed herein. Here, frothing device  400  includes a pitcher  402  disposed on top of a base  404 . The pitcher  402  includes a generally cylindrical body  406  having a top end  408  and an opposing bottom end  410 . A generally tapered inner bowl  412  defined by side walls and a bottom wall  414  separates the interior of pitcher  402  into a liquid compartment  416  and an opposing electrical compartment  418 . The tapering of the inner bowl  412  is defined by the side walls that extend inward and inclined to the body  406 . The pitcher  402  preferably includes a handle  420  attached about the top end  408 . A removable lid  422  is also disposed about the top end  408 . The pitcher  402  includes an on/off button  424  with status indicator lighting showing what program the device  400  is running. Base  404  contains electrical components  426  including a heater for heating up the milk. 
     The body  406  of pitcher  402  is preferably made of painted stainless steel with the bottom of the pitcher  402  made of plastic to aid in cleaning. The lid  422  is preferably made of clear polycarbonate with a rubber seal. The handle  420  is preferably made of a strong, phenolic resin. The on/off button  452  is preferably a capacitive touch switch. The inner bowl  412  is preferably soldered or the like to the interior of the body of pitcher  402  so there cannot be any leaks to the electrical components in the liquid compartment  416 . 
     The device  400  further includes a rotatable impeller  428  having blades  430  of varying dimensions and shapes depending on user preference, as discussed above in the context of  FIGS. 1-4 . The impeller  428  is disposed about a bottom end of a shaft  442  extending downward from lid  422 . As seen in  FIG. 10 , the shaft  424 , which is preferably a solid 4-5 mm rod, is fixed to the lid  422 . The shaft  442  is fixed to the lid  422  in a position off-center from the middle of lid  422 . The shaft  442  may also be fixed to an interior part of the body  406  rather than the lid  422 . In another alternative to having the shaft  442  fixed to the lid  422  with a rotating impeller  418 , the shaft  442  may be rotatably attached to the lid  422  to cause the impeller  428  to rotate. Or there may be no shaft  424  that hangs from the top of pitcher  402  but rather a rotatable shaft arrangement extending from the bottom wall  414 , as seen in  FIG. 14 . With such arrangement, impeller  454  with its blades  454  and holder  456  is removably attachable to first ring  460  as discussed above. Holder  456  and first ring  460  with screen  462  are identical in all respects to holder  432 , first ring  434 , and screen  440  discussed above except for a channel  458  cut into holder  456  and first ring  434  and corresponding hole cut into screen  464  to permit a rotatable shaft  462  to be inserted into the channel  458  and hole in the screen. All other electrical and drive aspects of this embodiment are the same as that disclosed above in the context of  FIGS. 9-13B . 
     Regardless of the specific structure of how the impeller  428  is designed to rotate within pitcher  402 , the impeller  428  is capable of being rotated at various speeds and up to 7,000 RPM to achieve the desired microfoam. Such speeds are believed to be unique to any frothing device. Device  400  achieves such speeds through the use of a pair of magnetic rings with strong magnets with opposing polarities that create a massive bond between the rings to drive the impeller  428 , as best seen in  FIGS. 11A-13B . 
     To elaborate, these figures show shaft  442  extending downward from lid  422  offset from its center. The rotatable impeller  428  has blades  430  and a holder  432  disposed about the blades  430 . The holder  432  has attachment means, such as a tongue and groove arrangement, for attaching the holder  432  to a first ring  434  directly beneath. The first ring  434  includes corresponding means for attaching the first ring  434  to the holder  432  such as tongue  436  extending from the inner wall of first ring  434 . Such an attachment arrangement permits the first ring  434  to be detachable from the holder  432  for ease of cleaning the first ring  434  and replacement or substitution thereof. First ring  434  also includes a ring of magnets  438  contained therein. The magnets  438  are preferably arranged with pairs of positive polarities  438 A disposed next to pairs of negative polarities  438 B as seen in  FIG. 13B . The electrical compartment  418  contains the corresponding second ring  448  disposed directly beneath the first ring  434  with the bottom wall  414  separating the two. Second ring  448  also contains magnets  450  with a combination of alternating positive and negative polarities  450 A,  450 B as best seen in  FIG. 13B . This second ring  448  is driven by a high speed, variable motor  444  with shaft  446  in communication with both motor  440  and second ring  448 , which in turn causes rotatable impeller  428  to rotate via the coupled first ring  434 . 
       FIGS. 13A-13B  also illustrate how impeller  428  has blades  430  and uses a screen  440  disposed about the impeller  428  in a downstream arrangement as discussed above. The screen  440  is contained by the first ring  434 . The impeller  428  is configured to move fluid from the top to the bottom of the impeller  428 , i.e., toward the screen  440  disposed under the impeller  428 . 
     The motor  444  runs special programs that vary the speed of the impeller  428  for managing various phases of the foam-making, allowing the user to make different densities of microfoam. In particular, through extensive experimentation and testing, a structure and methodology has been discovered to create constant and repeatable results with device  400 . First, as discussed above, the impeller  428  is correctly positioned off-center in device  400 . If an impeller were positioned in the center of pitcher  402 , microfoam would not be created because such impeller would very quickly create a full vortex and expose such impeller to the air. Doing so would only create big bubbles and would result in dry foam. Slowing such a centrally-positioned impeller down also would not work because it would spin too slowly to pull the big bubbles down. Second, the device  400  includes a tapered liquid compartment  416 . Such a tapered aspect provides a rather significant advantage from a straight-edged configuration. In particular, the tapered aspect obviates the need to measure the quantity of fluid contained in the liquid compartment  416 . Stated differently, a full vortex is more easily created with a small amount of milk that is dispersed evenly in straight-edged configuration. With the tapering, the milk pools in the middle of the liquid compartment  416 . Thus, knowing the quantity of fluid contained therein is not key. 
     Moreover, as seen with device  400 , when the impeller  428  is placed in its position offset from the center, it becomes possible to adjust the type of vortex created by adjusting the speed of the impeller  428 . To elaborate, with reference to  FIGS. 15A-15D , cold milk  466  is placed into the liquid compartment  416  and a program is selected by actuating the switch  424  until the indicator lighting shows the desired program to achieve the desired amount of foam. Regardless of the particular program selected, the general method of operation is the same. 
     As seen in  FIG. 15A , stage one begins with the impeller  428  turning very slowly to churn the milk  466  while it warms up to the correct temperature of approximately 40° C. No bubbles are created during this stage. 
     As seen in  FIG. 15B , stage two begins with the impeller  428  speeding up to a very high speed. Doing so aggressively churns the milk  466  to create a deep vortex  468 , exposing the impeller  428  to the air to create “normal” and/or big bubbles  470 . This stage of the program may run as short as just three seconds or as long as twenty seconds depending on how much foam is desired. 
     As seen in  FIG. 15C , stage three begins with the impeller  428  slowing down from its very high speed. The impeller  428  slows down just enough to prevent the vortex  468  from reaching impeller  428 . With the impeller  428  now fully submerged again, it can no longer make new bubbles. However, as the impeller  428  is offset from the center, the impeller  428  is still turning fast enough to pull the previously created bubbles down into the milk  466 , through the impeller  428 , and through the superfine mesh screen  440 . Here, the bubbles  432  get smashed into microscopic bubbles that remain suspended in the milk and create a homogenous milk-foam substance or microfoam  472 . 
     At the last stage as seen in  FIG. 15D , all the bubbles  470  have been drawn down and turned into microfoam  472 . The impeller  428  continues to churn at the same speed or gradually slows down until the milk reaches the desired final temperature of about 65° C. is reached. The device  400  then switches off. 
     One skilled in the art should now be able to glean quickly that the disclosed device  400  is capable of automatically heating milk and creating superfine microfoam milk. The resulting quality of the microfoam milk is indistinguishable from that prepared with an espresso machine steam wand. Yet, the user of device  400  need not have the skill of a professional barista knowledgeable about how best to adjust the position of the pitcher, milk, and steam wand during the process and to switch gradually from the aerating phase to a microfoaming phase. Device  400  therefore ameliorates the need to learn such skills and automates the entire process in a novel manner. 
     While certain embodiments have been described, the embodiments have been presented by way of example only and are not intended to limit the scope of the inventions. Indeed, the novel frothing devices and corresponding methods described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the disclosed elements may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.