Abstract:
The invention is a system and method of deploying an air extractor to motivate a stream of air to entrain particles of confetti or snow like medium. An air extractor moves air by means of Bernoulli&#39;s principle. A venturi tube constricts a flow of air creating a localized low pressure area at the throat of the constriction. A vent at the constriction induces a flow of air from the ambient atmosphere to this low-pressure area

Description:
[0001]    This application claims priority to provisional application serial No. 60/309,824 filed Aug. 2, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to theatrical effects and, more specifically, to dispersion of media.  
         BACKGROUND OF THE INVENTION  
         [0003]    Stage directors and others in the performing arts have struggled for a long time to produce realistic snowfall on stage. While media, such as paper confetti, Styrofoam bits, and soap flakes, have all served suitably as snow on both movies and theatrical sets, the means of launching media have been deficient. Additionally, stage directors have wanted to launch streamers and fog with the same equipment.  
           [0004]    To meet this need several various means have been used. One such solution, Pickens, U.S. Pat. No. 6,082,594 issued Jul. 4, 2000, agitates a hopper with paddles above a sifting screen. While this method does produce a gentle simulated snowfall but the hoppers have finite capacity. In the course of a production, the hoppers must be either refilled at regular intervals or there must be some additional mechanical means to convey a steady stream of media to the hoppers.  
           [0005]    A second method is to propel confetti and streamers in cannons pressurized by compressed air. Discrete loads of medium are loaded into the cannon and sudden discharge of gas will propel the medium to a discrete location. Shooting through such a cannon sends medium in compressed packets to the discrete location where, upon dispersion the display appears as a point sources. Such point sources are hard to blend into a natural snowfall.  
           [0006]    Another approach is that of Austin, U.S. Pat. No. 6,149,495 issued Nov. 21, 2000. Austin employs an electric motor running a turbine-type fan. Air at the fan&#39;s intake is drawn across a hopper filled with medium. The airflow across the medium entrains bits of the medium in the airflow, which is then drawn through the turbine-type fan, through the exhaust of the fan, and then is directed to a location suitable to create the effect.  
           [0007]    In addition, stage directors find that streamers and fog are not susceptible to turbine launch. Streamers are chopped by rotating turbine blades. Fog is mixed to the point of dispersion by the same blades. First, contact with the turbine blades simply ruins the medium. Second, where the particles of such a medium are easily damaged as would the medium used to simulate the slow fall of fluffy snow, the trip through the turbine-type fan blades can damage the individual particles of medium creating a disingenuous effect where as damaged particles fall much more rapidly to the floor. Such damaged medium is not reusable.  
           [0008]    What is needed, then, is a confetti, theatrical snow, streamer, or fog entraining device that is quiet and allows for continuous use and reuse of the theatrical snow or confetti.  
         SUMMARY OF THE INVENTION  
         [0009]    The invention is a system and method of deploying an air extractor to motivate a stream of air to entrain particles of confetti or snow like medium. An air extractor moves air by means of Bernoulli&#39;s principle. A venturi tube constricts a flow of air creating a localized low-pressure area at the throat of the constriction. A vent at the constriction induces a flow of air from the ambient atmosphere to this low-pressure area. Using this moving flow to entrain particles of medium, the invention transports the particles without passing them through any sort of fan. Thus, the danger of damaging the particles or clogging a fan is alleviated.  
           [0010]    The invention does not require a hopper of fixed dimensions. The induced air flow may be used to entrain as much of the medium as is necessary and can be constantly replenished. The invention requires no distinct conveyor but rather will continue to entrain particles of medium wherever the pickup is directed. In a preferred embodiment of the invention, the pickup can be used to draw medium off of a floor to constantly relaunch the medium. Such a cycle requires fewer particles for a better effect. So long as there is adequate supply available, the invented device can run continuously.  
           [0011]    Embodiments of the invention may be used to launch fog. Even cooled fog (cooled to increase its density, making the fog tend to cling to the floor) will be transmitted across great lengths without dispersing the fog or warming it.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.  
         [0013]    [0013]FIG. 1 is a cut away view of the air extraction nozzle used to motivate particles of media;  
         [0014]    [0014]FIG. 2 is a cut away view of the air extractor nozzle deployed with a fan as an integrated unit;  
         [0015]    [0015]FIG. 3 is the particulate flow path of particular media through the system; and  
         [0016]    [0016]FIG. 4 is a flow chart depicting an example process performed by the devices shown in FIGS. 1 and 2. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    [0017]FIG. 1 shows a cutaway view of the air extractor nozzle in a preferred embodiment of the invention. An air extractor nozzle  100  includes first and second chambers  102 ,  104 , connected by a communicating jet  108 . The first chamber  102  is adjacent to the second chamber  104 . The second chamber is elongated along the path of the jet  108  and opens into a horn  112  in communication with the environment. The elongation of the horn  112  connected to the second chamber  104  includes a constriction or venturi  110  to facilitate the Bernoulli Effect.  
         [0018]    In operation, the first opening of the first chamber  102  receives a flow of pressurized air  125  from a fan assembly  118 . The pressurized air  125  is released through the jet  108  into the second chamber  104  to produce a rapidly moving stream of air through the venturi  110 , and into the horn  112 . The pressure of the air within the moving stream drops at the venturi  110  according to the Bernoulli principle. As the pressure drops relative to the ambient air, the low pressure draws or entrains air from adjacent to the venturi  110  within the second chamber  104 , resulting in a flow of air  135  from the environment adjacent to throw the venturi  110  and out the horn  112 . The flow of entrained air  135  depends upon the volume and speed of the air flowing through the jet  108 . As the fan assembly  118  delivers more air at greater pressures, the flow of entrained air  135  becomes greater.  
         [0019]    [0019]FIG. 2 displays an embodiment deploying the air extractor nozzle  100  and the fan assembly  118  as an integrated unit  200 . The air extractor nozzle  100  is mounted and secured within a nozzle compartment  116  of a containing case  251  with an entry port  253  to the chamber  104  and an exit port  255  for the chamber  104 . The air extractor nozzle  100  is mounted on one or more pillow blocks  245  and secured within a bulkhead  247  that separates the nozzle compartment  116  from the fan assembly  118  that is in a fan compartment. In the preferred embodiment, the bulkhead  247  divides the fan compartment from the nozzle compartment  116  but may provide a seal the fan compartment or the periphery of the ports  253  and  255  provide a seal. The fan compartment includes a venting port  215  with louvers on an exterior bulkhead of the containing case  251 . The fan  210  feeds the air stream to the air extraction nozzle and a motor  240  that drives the fan  210 . As the motor  240  drives the fan it generates the air stream  125  (FIG. 1). The venting port  215  can be located on more than one side of the integrated unit  200 .  
         [0020]    In the preferred embodiment, the fan  210 , the motor  240 , and the venting port  215  are configured so as to promote air flow through and cooling the motor  240 . The utility of the venting port  215  is further enhanced when, in a preferred embodiment, acoustic foam acts as a filter and also prevents the promulgation of noise from the fan assembly  118  to the environment surrounding the containing case  251 . Even without the acoustic foam, the louvers in the venting port  215  divert acoustic energy and disperse it into the ambient. Elastomeric feet  258  further enhance acoustical isolation from the environment surrounding the containing case  251 . These feet  258  allow the unit  200  to rest either as shown in FIG. 2 or rotated to rest such that the port  255  is directed upward.  
         [0021]    Also visible in FIG. 2 are optional features that enhance the invention&#39;s versatility in stage use. An internal electrical path allows remote control by alternately providing electrical power. The electrical path includes an internal electrical cord  225  connection the electrical motor  240  through a switch  235  and on to a male surface mount connector  230 . In a preferred embodiment, this connector  230  is fused. By virtue of these connections, the fan assembly  118  can be controlled either by manually operating the switch  235 , or with the switch  235  in the closed position, connecting the unit by the connector  230  to a suitably switched power line (not shown) providing, thereby, remote control of the unit.  
         [0022]    Additionally, a bracket  271  is mounted to the case  251 . This bracket is articulatable and fixable at appropriate angles and extensions allowing an adjustable fixation point that can be suitably adjusted based upon application. This preferred embodiment is known in the art as “gimbel” mounting. This bracket  271  can be appropriately fixed to scaffolding, catwalks, and booms. Once the exit port  255  is suitably directed, the unit  200  can wait, dormant, until suitably energized through the connection  230 . Upon energizing the connection  230 , the unit  200  will launch such media as are available to the pickup  281  (FIG. 3).  
         [0023]    [0023]FIG. 3 displays the path of the second airflow  135  through the device described above in FIG. 2. As discussed in FIG. 1, the gas extracting nozzle assembly  100  generates at least a partial vacuum at the intake port  253  when supplied with an air stream from the fan assembly  118  (FIG. 2). Ducting  280  such as hoses or tubes are used to conduct the localized relative vacuum at  253  along the hose to a pickup end  281  of the ducting  280 . At the pickup end  281  the localized vacuum generates an airflow  135  that entrains particles of medium  275  much as the airflow to a vacuum cleaner might entrain particles of dust in a carpet. From the pickup end  281 , the airflow  135  with the entrained particles of medium travels along the ducting  280  through the intake port  253  and through the air extractor nozzle out through the exit port  255  and along ducting  285  to the desired location. In this manner the particles of medium have never been in contact or even in close proximity to the fan assembly  118  (FIG. 2).  
         [0024]    The unit  200  can be remotely mounted above a stage or proximate to the ceiling of a dancing establishment. From that position hoses lead to a remote area can supply confetti on demand. An operator can interrupt power flowing to the unit  200  to effectively control when the unit will project particles of medium. The medium itself may be stored in a hopper or with a conveyor belt to assure a constant feed to the pickup end  281 . Similarly, if the pickup is on a flexible hose an operator can use the pickup end  281  directing it at supplies of particles of medium much as one might use a hand tool attachment to a vacuum cleaner.  
         [0025]    [0025]FIG. 4 illustrates a method  300  by which particles of medium are projected through the device shown and described above. First, at block  303 , an airstream is generated and sent through a vented venturi. It will be readily appreciated that any means of motivating air through the venturi tube will work. The simplest embodiment, a bleed off a high pressure airline will suffice as will other embodiments such as an auxiliary fan or compressor. Even exotic technology such as an ion jet will serve to motivate the airflow. Any airflow will do.  
         [0026]    The vented venturi tube has a constriction or venturi in the center. At the venturi the pressure within the moving stream of air drops due to the Bernoulli effect. The vent at the venturi takes ambient air at a higher pressure and draws it toward the low pressure. That movement of air entrains other gasses until a full stream of ambient air is generated, block  306 .  
         [0027]    The movement of the entrained air can be ducted at block  309 . As with any localized low pressure zone, a hose or duct can be used to transfer that localized low pressure to a remote location. A hose for a vacuum cleaner demonstrates the principle. At a remote pickup, the localized low pressure zone draws air from the atmosphere surrounding the pickup causing an air stream to flow.  
         [0028]    The flowing air stream entrains medium at block  312 . As the flow enters the pickup, where medium is in close proximity to the pickup, the flow can entrain medium. As has been indicated in the preceding discussion, the air flows from the pickup, through the ducting, into the air extractor nozzle and out through the horn of the air extractor nozzle. With the air flow, so flows the medium. At block  315 , the nozzle is directed where the flow of the medium is desired.  
         [0029]    While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment.