Abstract:
The present invention is a small bubble generator in a water stage cleaning and cooling a smoke filled air stream. A demister is a second embodiment of the invention to remove entrained water droplets from a cleaned and cooled smoke filled air stream issuing from the water stage.

Description:
This application claims the benefit of Ser. No. 60/360,319 filed Feb. 28, 2002. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to water pipes using more than a single stage of water to condition smoke before it reaches the user&#39;s mouth. 
   U.S. Pat. No. 4,357,948 shows a water pipe with a device located in a tube above a bottom water reservoir. The device can only form large and non-uniform bubbles from smoke filled air passing through water retained in the device. The device loses almost all effectiveness when tilting it more than a few degrees from vertical, as a relatively low water head at one side of the tube allows all the smoke filled air to escape through the water at the point where the depth is smallest. 
   SUMMARY OF THE INVENTION 
   A first embodiment of the invention is a small bubble generator system for smoke filled air generated from in a pipe and drawn by vacuum force of human lungs through a water stage. The first embodiment preferably processes the smoke filled air after contact in large bubbles with a main body of water. The main body of water may be the lowest bowl or container of water in a prior art water pipe. 
   A small bubble generator by the invention process has proven to have resulted in a dramatically more pleasurable smoking experience for the user. The reasons for this improvement are clear in retrospect after the inventors experimented with several alternate methods. 
   Smoke filled air drawn from a pipe bowl or from another source of burning vegetable matter is hot and filled with microscopic particles comprising carbon, tars, partly burned vegetable matter fibers, dirt and dust, and other non-volatiles, as well as vaporized hydrocarbons, pesticides, carbon dioxide, carbon monoxide, and typical components for reduced oxygen air. The components of smoke that are desired by the user are typically a complex mixture of hydrocarbons and a sometimes a portion of the particulates. 
   Excluding the desirable components, the balance of the components are undesirable and typically unhealthy. A user would prefer to exclude at least some of the undesirable components. In addition, a typical user has been found to prefer a lower temperature smoke filled air stream to draw into their lungs, albeit a stream sufficiently high in the desirable components to provide the smoking experience desired. In this application, the phrase “first smoke stream” will refer to a smoke filled air stream drawn directly from a pipe bowl or from another source of burning vegetable matter by vacuum force of only human lung power. 
   Conventional water pipes capture some of the undesirable components of the first smoke stream and cool the stream some few degrees. This is done by drawing that first smoke stream to a bottom of a lower bowl of water to form in the water relatively large bubbles that rise through the water. A relatively large gas space is provided above the water for disengaging water droplets from the released bubbles. The diffusers in that lowest bowl for the first smoke stream are commonly just glass or metal tubes that run from a pipe bottom to an end under the water, where the first smoke stream exits the tube through a few holes. The bubbles exiting those holes have an average inside diameter of about 3 millimeters or more. 
   The inventors have found that reducing the average inside diameter of the bubbles to about 2 millimeters or less in one or more water stage upstream of a user dramatically reduces the emerging gas temperature and removes substantially more of undesirable smoke components that prior art devices. However, making small bubbles in a smoke filled gas stream has an important cost. 
   Making a gas stream to pass through a small hole is the best way to make a small bubble. A gas stream with particulates and tars will eventually plug that hole. That is the cost of making small bubbles for water pipes. 
   The present inventors attempted replacing the holes in the end of the glass or metal tube in a water pipe with a sintered “stone” used in aquariums to generate small bubbles. The device worked well to make small bubbles but had a very short life. The small passages of the stone plugged and could not be cleaned. The present inventors then experimented with several alternate structures to arrive at the first embodiment of the invention. The first embodiment accelerates a smoke filled gas stream to impinge on an underside of a top cap and then down from the top cap to small accelerator openings that emit the smoke filled gas as small bubbles into a volume of water. The pressure drop of the gas across the accelerator openings that is substantially greater than the pressure drop through the water the bubbles encounter on the water stage. This means a user may tilt the invention water stage to 45 degrees or more with little, if any, reduction in desired performance. 
   A second embodiment of the invention is a mist eliminator. The act of drawing smoke filled air through water with inhalation vacuum of a human typically generates substantial water droplets carrying upward from the surface of the water. However, prior art water pipes have been designed with very substantial upward extensions of the enclosure above the lowest bowl of water and/or expanded lateral cross sections above the water so that the water droplets from that lowest bowl of water do not reach the user&#39;s mouth. tubes very extended When a water stage is placed somewhat nearer the user&#39;s mouth than the water level of water in a lowest bowl or container of water in a prior art water pipe, a sensible and annoying amount of water droplets get pulled into a user&#39;s lungs. The second embodiment is similar to the first embodiment but eliminates a central tube with an annular space within the structure of the top cap. The droplet laden gas stream impinges on an underside of that structure and is forced through elevated side slots to impinge on the inside surface of the largest bore of the outside housing. The droplets adhere to one of those impingement surfaces and drain to a water stage below the second embodiment. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is side and cutaway view of a lower water reservoir with two embodiments of invention stages shown above it. 
       FIG. 2  is a close up of section  122  of FIG.  1 . 
       FIG. 3  is cross section  109  of FIG.  1 . 
       FIG. 4  is an operational view of  FIG. 2  in an upright position. 
       FIG. 5  is an operational view of  FIG. 2  in a tilted position. 
       FIG. 6  is a close up of section  119  of FIG.  1 . 
       FIG. 7  is an operational view of  FIG. 6  in an upright position. 
       FIG. 8  is cross section  113  of FIG.  1 . 
       FIG. 9  is cross section  144  of FIG.  6 . 
       FIG. 10  is cross section  144  of  FIG. 6  with an alternate slot form. 
       FIG. 11  is an axial cross section view similar to  FIG. 4  with another form of the first embodiment. 
       FIG. 12  is an axial cross section view similar to  FIG. 4  with another form of the first embodiment. 
       FIG. 13  is an axial cross section view similar to  FIG. 4  with another form of the first embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention is now discussed with reference to the figures. 
     FIG. 1  shows a water pipe  100  with the two invention stages  109  and  113 . Additional upwardly sequential stages  109  and  113  can be stacked on the stages shown so that housing  118  with the central bore extends upward to accommodate those stages. Stage  109  is an invention water stage of the first embodiment. Stage  113  is an invention demister stage of the second embodiment. Each of stages  109  and  113  can operate independently of each other. Stage  109  may be primary water stage processing a first smoke stream or may process smoke filled air streams downstream of other processing stages. Stage  113  may act as a demister without the previous process of smoke filled gas accomplished on stage  109 . Stage  113  can remove water droplets from smoke filled air from a water stage such as that shown in  FIG. 1  in container  129 . 
   Container  129  in  FIG. 1  is preferably a glass or other water containing container that can retain a water volume  101 . Pipe bowl  128  retains burning vegetable matter, and a first smoke stream  103  is drawn from bowl  128  through tube  102  through diffuser end  127 . Stream  103  issues from diffuser end  127  as bubbles greater than about 3 millimeters in water volume  101  to form bubble stream  104 . The bubbles of stream  104  burst and form second smoke stream  105 , which in turn flows to opening  125  at the base of housing  118 . Stream  105  passes through opening  125  and into stage  109 , wherefrom a third smoke stream passes to stage  113 . After the third smoke stream is processed in stage  113 , it emerges as a fourth smoke stream from a top end of housing  118  to be drawn into a user&#39;s mouth and lungs. 
   With reference to  FIGS. 1-5 , stage  109  comprises a portion of housing  118  and its central bore. To an inside wall of the central bore is sealed floor plate  107 . Plate  107  defines an opening  106 , from which extends upward a tube  123  that ends in opening  132 . A preferred inside diameter of tube  123  is from about 5 to about 20 millimeters and a more preferred inside diameter is from about 10 to 14 millimeters. Enclosing tube  123  is a structure comprising a top cap  133  extending down to side walls  110 , at whose base are located small accelerator holes  157 . Holes  157  in a first embodiment are rectangular extending from a top of floor  107  up to a height of from about 0.5 to about 4.5 millimeters and a width of from about 0.5 to 5.5 millimeters with a hydraulic cross section area of about from 1-10 square millimeters, and more preferably from about 2-4 square millimeters. 
   An inside surface of housing  118  and an outside surface of walls  110  define annular space  108 . An inside surface of walls  110  and outside walls of tube  123  define annular space  124 . The sole connection fluid conduit connections between space  108  and  124  are holes  157 . Space  108  opens to an open area within housing  118  above cap  133 . An alternate embodiment of holes  157  are shown in FIG.  3 . Holes  134  comprise extensions so that fluid exiting space  124  to space  108  is forced into a tangential or other angled relationship to the straight through orientation of holes  157 . Holes  134  result in fluid direction  135  as fluid is drawn from space  124  to space  108 . Holes  157  result in fluid direction  136  as fluid is drawn from space  124  to space  108 . A preferred clearance between the top of tube  123  and the topmost part of the underside of cap  133  is about 0.25 to 2 inches. Generally, the small openings may direct gas flow radially, tangentially or at any other angle with respect to the outside surface of the wall defining the small opening. 
   The operational  FIGS. 4 and 5  are now referred to with respect to the invention process for the first embodiment. Second smoke stream  105  is drawn by vacuum force of human lungs into opening  106  from the much wider cross section below it defined by the inside walls of housing  118 . This dramatically increases the velocity of stream  105 . Stream  105  passes through tube  123  to impinge on the underside of cap  133 , causing substantial turbulence and swirling. From cap  133 , stream  105  is drawn down through space  124  to holes  157 . The cumulative hydraulic cross section area of all of holes  157  is preferably much less than that of space  124  so that stream  105  passing through those holes  157  in one form of the invention experience a substantial acceleration. Stream  105  then passes into liquid  140  and liquid  141  (preferably water), liquids  140  and  141  being located on substantially opposite sides of space  108 . Liquids  140  and  141  remain outside of space  124  by action of stream  105  passing into them, although when stream  105  is not flowing, liquid may flow into that space  124 . If the level of liquids  140  and  141  are too high when stream  105  is not flowing, excess liquid spills into tube  123  and down to a next water stage. Water added from above stage  109  can spill into space  108  and will thereby only rise to the level of the top of tube  123 . This is a method of adding water needed for operation of the invention water stages. 
   Bubbles  158  in  FIGS. 4 and 5  have an average internal diameter of from about 0.5 millimeters to about 2 millimeters. A feature of the invention process is found in the acceleration of stream  105  through the small accelerator holes. Bubbles  158  move initially after formation from stream  105  in directions  136  or  135  shown in FIG.  3 . When acceleration is substantial, this forces small bubbles into intimate contact with the inside wall of housing  118 , where electrostatic attraction for a glass or metal surface causes the bubbles to frictionally resist rising as if open water. This increased residence time improves heat and mass transfer between the bubbles and the liquids  140  and  141 . Thus, more undesirable components are removed and the temperature is reduced by humidification of the gas in the bubble. 
     FIG. 5  shows that the first embodiment is very adaptable to tilting, an activity that lets a user move about with the device  100 . In  FIG. 5 , liquid  140  has a much reduced liquid pressure head compared with that shown in FIG.  4  and even much less than that of liquid  141  of FIG.  5 . In prior art devices, stream  105  would necessarily flow almost entirely through fluid passages to the shallow liquid  140  side because the pressure drop has been reduced. In the first embodiment, the pressure drop across holes  157  is so substantial that the change in liquid head height has little effect on the operation of reducing temperature and removing undesirable components. In  FIG. 5 , it can be appreciated that the bubbles  158  of liquid  140  have a short residence time in the water or liquid, where the bubbles  158  of liquid  141  have a relatively long residence time in the water or liquid. So, where in  FIG. 5  about half of all the bubbles would be less treated in liquid  140 , the other half would be over treated in liquid  141 . The invention uses small holes for bubble generation around a lower part of a periphery of a shell with a relatively large outside diameter. The result is even distribution of smoke filled air flow among the holes to that periphery so that substantially the entire volume of water or other liquid is in close contact with smoke filled bubbles. The prior art does not disclose such an efficient device as the invention. 
     FIGS. 7-9  are a second embodiment of the invention.  FIG. 7  shows that a floor  112  seals to the inside surface of the largest bore of housing  118 . Floor  112  defines opening  111  that opens to a space  145  defined by cap  146  (similar in structure and function to cap  133 ) and walls  142 . Openings  114  communicate between space  145  and annular space  153  between the inside walls of the largest bore of housing  118  and the outside surface of walls  142 . Slots  117  are formed about an inch or more below the top of cap  146  and at about a transition from walls  142  to cap  146  and are supported at sections  148  (shown in FIG.  8 ). The operation of the demister is shown in FIG.  7 . Water droplets are carried up by a third smoke filled gas stream  150  through opening  111  into space  145 . Droplets  152  impinge on an underside of cap  146 , adhere thereon and drain down walls  142  to opening  111  where water flow  143  drains to a water stage below. Droplets  160  are drawn through slots  117  and impinge on the inside walls of the largest bore of the housing where they adhere and drain in film  161  to flow  157  through openings  114 . 
   The second embodiment, with vane slots  117   a  of  FIG. 10 , surprisingly causes stream  150  being drawn through vane slots  117  to be forced into an especially pleasing spiral pattern in space  153  in paths  156   a  (in  FIG. 7 ) and  163   a  (in FIG.  10 ). Streams  156 ,  156   a  and  156   b  leave space  147  conditioned to be inhaled by a user. 
     FIGS. 11 ,  12  and  13  are alternate forms of the first embodiment.  FIGS. 11 ,  12  and  13  respectively show small bubble generating stages  170 ,  179  and  197 . Each respectively has a housing bore-sealing floor  171 ,  180  and  107 .  FIG. 11  shows that opening  172  in floor  171  extends to an upside down U-tube  173  that extends above the level of liquid  176  and back into liquid  176  to end part  174  that has small openings  175  with the bubble generating capabilities of the above first embodiments. Stream  105  passes through tube  173  on path  177  to form bubbles  198 , which are released from the liquid  176  to form stream  178 . The form of  FIG. 11  somewhat reduces the fabrication costs, although the requisite narrow tube  173  will typically cause the bubbles  198  to pass through only a relatively small portion of liquid  176 . 
   The form of  FIG. 12  improves the liquid distribution of bubbles  187  in liquid  186  contained in container  181 . Container  181  is a downward extension of a large opening in floor  108 , which is sealed to the inside bore of housing  118 . A tube  183  extends from an upper opening  182  in the side wall of container  181  down into liquid  186  to a flared end  184  that comprises the invention small openings in a periphery of end  184 . Stream  105  enters stage  179  and along path  199  is drawn into an annular space between the outside walls of container  181  and the inside of the bore of housing  118 , thereafter into tube  183  and out the small openings into liquid  186  to form bubbles  187 . Bubbles  187  are freed from liquid  186  to form stream  188 . 
   The form of  FIG. 13  as stage  197  is similar to the form of  FIG. 4 , except that wall  190  is extended laterally at floor  192  to sealingly connect with the inside bore of housing  118 . A space is formed between the upper surface of floor  107  and the underside of floor  191 , in which are formed the invention small openings  192 . Stream  105  is drawn into stage  197  along path  193 , into tube  123  and then into the annular space between the outside of tube  123  and the inside of cap  189  that extends down to walls  190 . Bubbles  196  are formed in liquid  195  as the smoke filled gas is drawn through openings  192 , which are then released to form stream  194 . 
   It is an especially important feature of the embodiments that they are easily cleaned with an alcohol and salt solution. It preferred that at least two successive first embodiment water stages are used above the first water contact of the first smoke stream of FIG.  1 . 
   It will be seen that the forms of the first embodiment provide that the small openings may be located in a lower or lowest edge of a conduit which is immersed in the filtering liquid. 
   The above design options will sometimes present the skilled designer with considerable and wide ranges from which to choose appropriate apparatus and method modifications for the above examples. However, the objects of the present invention will still be obtained by that skilled designer applying such design options in an appropriate manner.