Abstract:
A drinking straw for delivering a hot liquid in the form of a foam into a user&#39;s mouth that mimics the natural action of sucking in air for cooling the liquid. The straw has a tube wall with an expanded portion proximate an outlet. Air admitting orifices are provided in the tube wall below the expanded portion so that air is drawn into the straw through the orifices when a liquid is sucked through the straw. The straw may be used for cooling a hot liquid such as coffee, tea, soup or the like and may be used in connection with a container.

Description:
This application claims priority from provisional application Ser. No. 60/687,726, filed Jun. 6, 2005, for Drinking Straw for Heated Liquids, Method of Cooling and Combination with Drinking Vessels. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a drinking straw which delivers a hot liquid into the mouth of a user in the form of a foam and to a method wherein the hot liquid is cooled in the user&#39;s mouth as the foam collapses such that the mouth of the user is not burned. The drinking straw may be provided separately or in combination with a drinking vessel. 
   2. Brief Description of the Prior Art 
   To reduce the chance of burning the mouth, people instinctively sip a hot liquid. The sipping process mixes the hot liquid with air, thus creating an air-liquid mixture. The air keeps the liquid from burning the user&#39;s mouth while the liquid cools. 
   Other than with the natural technique, inventive attention has been directed to cooling the hot liquid before it reaches the user&#39;s mouth. But a cooled drink and a hot drink have different flavors. U.S. Pat. No. 5,288,019 to Gorochow is illustrative of the prior art. 
   The idea of perforating a straw such it introduces bubbles into a drink for the purpose of improving the drink&#39;s palatability was described in U.S. Pat. No. 2,943,794 to Sussman. The tube wall in the Sussman patent is straight and the bubbles introduced into the drink tend to be small. When such a straw is used with a hot liquid, the liquid is slightly cooled as it flows through the straw but it is still hot when it reaches a user&#39;s mouth and the bubbles are not large enough to effectively form a foam. 
   In view of the above, what is needed is a drinking straw and a method of cooling a hot liquid that mimics the natural action of sucking in air for cooling the liquid. 
   BRIEF SUMMARY OF THE INVENTION 
   In view of the above, it is an object of the present invention to provide a drinking straw and a method of cooling that mimics the natural action of sucking in air for cooling a hot liquid. It is another object to provide a drinking straw and a method of using it for delivering a hot liquid into the mouth of a user without substantially precooling the liquid. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter. 
   In accordance with the invention, a drinking straw is provided with a tube wall having an inlet on the lower end and an outlet on the upper end. The tube wall has at least one expanded portion proximate the outlet. The volume of the expanded portion is larger than the volume of the tube below the expanded portion such that the pressure on a hot liquid being drawn through the straw is reduced in the expanded portion. 
   Air-admitting orifices are provided in the tube wall below the expanded portion so that air is drawn into the straw through the orifices when a liquid is sucked through the straw. The air forms bubbles at the orifices which are entrained in the liquid being sucked through the straw. As the bubbles enter the expanded portion and region of lower pressure, the flow rate of the fluid slows down giving the bubbles time to enlarge and coalesce before being sucked as a foam into the user&#39;s mouth. Drinking straws in accordance with the present invention thus provide a method of delivering liquids such as coffee, tea, soup and the like to the user&#39;s mouth in hot, delicious form without risk of burning. 
   A plurality of expanded portions interconnected by restricted portions may be provided. The expanded portions may be similarly sized or may increase in size in the direction of the outlet such that the bubbles increase in size as they are sucked through the drinking straw. In some embodiments, the outlet may have even greater volume than the expanded portions previously discussed. Air-admitting orifices may be provided in a restricted portion of the tube before entering that portion also. 
   The plurality of expanded portions may be formed as a flexible joint that allow the outlet portion of the straw to articulate with respect to a portion of the straw on the other side of the joint. The tube wall may also be formed in telescoping sections. A first section including the outlet may have a larger diameter than a second section including the inlet with the expanded portions being formed in the lower end of the first section. As the second section is slid into the first section, the second section may selectively block the orifices in the expanded sections allowing a user to control the air/liquid proportion in the foam delivered to his or her mouth. 
   Other means for controlling the air/liquid proportion in the foam are also described. For example, a sleeve may be provided on the outside of the tube wall for selectively blocking the orifices in the expanded sections. In other embodiments where the expanded portions form a flexible joint, contracting the joint may be used to selectively block the air-admitting orifices. When the a spiraled groove is used to form the expanded portions, the air-admitting orifices may be blocked by finger pressure in the groove. 
   To minimize or prevent the liquid from leaking out of the drinking straw through the air-admitting orifices, the orifices may be sloped inwardly and downwardly such that the liquid tends to be drawn back into the tube when the user stops sucking and the liquid falls back down the tube. When the orifices are formed in a nipple, the nipples may be formed inside the tube or outside the tube. 
   Drinking straws in accordance with the present invention may be used with conventional containers such as cups, bottles and the like. They may also be used with specially formed containers. For example, an attached lid of a cup may include an inverted pyramidal shaped cavity through which the inlet end of the straw is passed. As may be appreciated, the cavity tends to funnel any liquid that may spill from the outlet back into the container. Other examples include bottles with an attached lid in which a drinking straw with a contracted flexible joint may be received. When the lid is removed, the drinking straw may be extended as used as described above. Alternatively, the inside of the neck of the bottle may be threaded for receipt of cooperatively threaded expanded portions such that the air/liquid proportion may be controlled by threading the drinking straw up and down in the neck of the bottle. 
   Drinking straws in accordance with the present invention may also be provided with a means for heating the liquid before it is aerated in the expanded portions of the drinking straw. Such heating means may be electrically or chemically powered. 
   The invention summarized above comprises the constructions hereinafter described, the scope of the invention being indicated by the subjoined claims. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated, corresponding reference characters refer to corresponding parts throughout the several views of the drawings in which: 
       FIG. 1  is a cross-sectional view of a prior art drinking straw such as described in U.S. Pat. No. 2,943,794 to Sussman; 
       FIG. 2  is a cross-sectional view of a drinking straw in accordance with the present invention; 
       FIG. 2A  is a side elevation of a multi-chambered drinking straw in accordance with the present invention illustrated in partial cross-section; 
       FIG. 3  is side elevation illustrating a user using a drinking straw in accordance with the present invention in combination with a bottle; 
       FIG. 3A  is an illustrative cross-sectional view of a user&#39;s mouth during delivery of a hot liquid in a foam; 
       FIG. 4  is an enlarged side elevation of a drinking straw in accordance with the present invention illustrated in partial cross-section and with the inlet end broken away, said drinking straw having adjustable air admission means; 
       FIG. 4A  is an enlarged cross-sectional view of an air-admitting orifice in the form of an internal nipple taken from  FIG. 4 ; 
       FIG. 5  is an enlarged side elevation of a drinking straw in accordance with the present invention illustrated in partial cross-section and with the inlet end broken away, said drinking straw having a flexible joint; 
       FIG. 6  is an enlarged cross-sectional view taken from  FIG. 5 ; 
       FIG. 7  is an enlarged cross-sectional view taken from  FIG. 5 ; 
       FIG. 8  is an enlarged cross-sectional view similar to  FIG. 6  but having a drip-protection folding; 
       FIG. 9  is a cross-section illustrating one method of forming an air-admitting orifice in a tube wall of a drinking straw in accordance with the present invention; 
       FIG. 10  is an enlarged side elevational view of a drinking straw in accordance with the present invention with the air-admitting orifices in the form of external nipples; 
       FIG. 11  is an enlarged cross-sectional view taken from  FIG. 10 ; 
       FIG. 12  is a side elevational view of a cup with an attached novel cup lid in cross-section illustrated with a multi-chambered drinking straw in accordance with the present invention; 
       FIG. 13  is a side elevational view of a bottle in cross-section with an attached threaded lid illustrated with a drinking straw with a flexible joint, said joint in contracted condition; 
       FIG. 14  is an enlarged side elevational view of the bottle shown in  FIG. 13  with the lid detached and with the flexible joint extended; 
       FIG. 15  is an enlarged side elevational view of a top portion of a bottle with an open neck illustrated with a multi-chambered drinking straw in accordance with the present invention; 
       FIG. 16  is an enlarged side elevation view of a top portion of a bottle with a threaded neck illustrated with a drinking straw in accordance with the present invention having a screw-type of air adjustment means; 
       FIG. 17  is an enlarged cross-section of a drinking straw in accordance with the present invention with the inlet end broken away, said drinking straw having air-admitting orifices which may be blocked with the user&#39;s fingers; and, 
       FIG. 18  is an enlarged cross-section of a drinking straw in accordance with the present invention illustrated with a heating means for heating the liquid as it is sucked through the straw. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings more particularly by reference character, as shown in  FIG. 1  reference numeral  21  refers to a drinking straw in accordance with the present invention. Drinking straw  21  mainly comprises a hollow, continuous flow passage tube and includes the following connecting portions: A bottom portion  23  is intended for lowering into a drinking liquid. An area  25  includes air-admitting apertures  24  for bringing outside air into the drinking straw during suction. A top portion may perform a combination of two functions—namely, a bubble-expansion chamber and a mouthpiece. 
   A hot liquid  26  enters a drinking straw inlet  22  when a user applies suction and travels upwards to area  25 . Upon entering area  25 , outside air is pulled into the liquid through air-admitting apertures  24 . The aerated liquid is then pulled into an area  31 . Area  31  includes a chamber  27  that has a larger volume than portion  23  within area  25 . The small bubbles  26 A in chamber  27  are permitted to expand in size due to the lower pressure in the chamber. Since the flow rate through chamber  27  also slows, small bubbles  26 A also have more time to coalesce and form larger bubbles which then also expand. The enlarged bubbles  28  form a foam-like mixture which has a greater proportion of air than liquid. The foam exits from an outlet  30  into the user&#39;s mouth as shown in  FIG. 3A . As shown in  FIG. 3A , the foam passes between a user&#39;s lips  100  into oral cavity  101 . The hot liquid is carried as a film on enlarged bubbles  28  and when the foam comes in contact with user&#39;s lips  100  and oral cavity  101 , the foam is dissipated before the liquid passes down throat  103 . 
     FIG. 1  shows the structure of Sussman&#39;s drinking straw with apertures for admitting air for the purpose of simulating carbonation. The same reference characters used with respect to drinking straw  21  have been applied to corresponding structures. The outlet is identified as  30 S. The bubbles formed in Sussman&#39;s straw are smaller than in the straw described above. 
     FIG. 2A  shows another embodiment of the present invention wherein straw  21  is telescopic. Telescopic straw  21  includes bottom tubular part  23  with inlet  22 , which is inserted into a sleeve  27 C of upper tubular part  27 F which is chambered. Chambered part  27 F includes a plurality of chambers  27 S connected to mouthpiece  27 , having outlet  30 . A plurality of air-admitting apertures  24  are located in areas between the chambers, said necks having smaller cross-section than the chambers. Air-admitting apertures  24 S are also provided between mouthpiece  27  for admission of additional bubbles. The cross-section of necks between chambers  27 S may be substantially the same as the cross-section of tube  23  such tube  23  may be slide up and down inside chambered part  27 F. Telescopic movement of the parts enables opening and closing air-admitting apertures  24  and enables the user to regulate the air/liquid proportion in the foam-like mixture. A mixture having a higher proportion of air will increase the cooling effect on the hot liquid while a mixture with a lower proportion of air will decrease the cooling effect. 
     FIG. 4  illustrates another embodiment of the invention. A straw  21 A has four major portions: Bottom portion  23 D, which is intended for lowering into the liquid, is connect to chambers  27 S. Chamber  27 S are connected to larger cross-sectional chamber  27 , which is connected to mouthpiece  29  of outlet  30 . Mouthpiece  29  may have a flap  29 F to protect the user&#39;s lips from heat. Chambers  27 S may have air-admitting apertures constructed as nipple-like in shape.  FIG. 4A  is an enlarged cross-sectional view of a nipple  38 N, having air inlet  24  and air outlet  50 . It is preferable that outlet  50  be positioned lower than inlet  24  so that liquid may drain into the straw when suction is released and the liquid falls in the tube. In addition, nipple  38 N reduces the noise of entering air. A tubular shaped regulator  38  has an inner diameter that is substantially the same as the outside diameter of chambers  27 S and can be slid up or down by the user in order to open or close the desired number of air-admitting apertures. A cuff  35  of regular  38  stops movement past detent  23 E. The adjustment will change the air/liquid proportion in the mixture, allowing the user to control the desired level of cooling needed to prevent burning of his or her mouth. 
     FIG. 5  is represents another embodiment of the present invention. Drinking straw  21 B includes a flexible joint which may be variant of the joint described in U.S. Pat. No. 3,409,224 to Harp which is incorporated by reference herein. Sides  41  and  41 A, when in unfolded position form foam generating and mixing chambers  27 A. Each chamber connects to an adjacent chamber by means of air admitting apertures formed in grooves  32  which are shown in enlarged cross-section in  FIG. 6 . Grooves  32  have air-admitting openings  33 , which permit outside air to be drawn into the straw through apertures  24 . It is preferred that apertures  24  be positioned lower than opening  33  to prevent egress of liquid from escaping the straw.  FIG. 7  is an enlarged cross-section view of one of the chambers in a collapsed position, in which air admission is restricted. In the collapsed position, groove  32  and tube wall  41 B seal air admission to apertures  24 . In  FIG. 5 , reference character  60  refers to a region wherein the chambers are collapsed and reference character  60 A refers to a region where the chambers as expanded. The embodiment shown in  FIG. 5  allows the user to open and close the desired number of chamber and air admitting apertures to regulate the air/liquid proportion of the foam mixture for temperature adjustment.  FIG. 8  is a cross-sectional view of a variant of air-admitting fold  36  with side walls  36 A and  36 B shown in  FIG. 6 .  FIG. 9  illustrates a way in which a needle  37  may be used to form apertures  24  in air-admitting fold  36  which is illustrated partially unfolded. 
     FIG. 10  is a partial view of a further embodiment of the invention with mixing chambers  27 C where air-admitting apertures  24  may be positioned on the tip of external nipples.  FIG. 11  is an enlarged view of external nipples  38 . As shown, aperture  24  is preferably positioned higher than air outlet  50 A to prevent the liquid from escaping from the straw. 
     FIG. 12  demonstrates a combination of a novel straw  21 C with a novel container lid  81  for a container  80  with an air hole  82 . Novel lid  81  includes an inverted pyramidal shaped cavity  83  for preventing the escape and funneling collected liquid back into the container. Plurality of chambers  27 M have increasing volume in the direction of upper bulbous chamber  27 . 
     FIG. 13  is a cross-sectional view of a combination of a novel straw  21 E with a bottle  70  with a threadedly attached lid  74 .  FIG. 14  is an enlarged cross-section view corresponding to  FIG. 13  of a novel straw  21 D with lid  74  removed exposing threads  73 . A side wall  71  of one of chambers  72  may serve as a stop preventing the removal of the straw from bottle  70 . 
     FIG. 15  depicts another embodiment of the combination of a drinking straw  21 D in accordance with the present invention with a bottle  70 A.  FIG. 16  shows a further embodiment of the combination of a novel straw  21 K with a bottle  70 B utilizing a screw type design wherein chambers  27 N screw into threads  75  provided in the neck of the bottle thereby providing air-adjusting means. 
     FIG. 17  shows a still further example of a drinking straw  21 L in accordance with the present invention. As shown downwardly sloped grooves  32 A form air-admitting nipples  38 M proximate the inlet end. Groove is sufficiently wide that the user may use his or her fingers to block air-admitting apertures  24  and control the air/liquid proportion of the foam. 
     FIG. 18  illustrates a drinking straw  21 G wherein a heating means  39  is provided for heating the liquid before it is admixed with air. Heating means  39  may be powered by an electrical or chemical heating source as will occur to one skilled in the art. It will also be apparent that heating means  39  may be located outside drinking straw in the container from which the liquid is being sucked. Such self-heating containers are known in the art. 
   In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.