Abstract:
A fog effects system includes a control system, a fog fluid reservoir, an elongated insulator, an elongated electric heating element, an air supply subsystem, a fog fluid supply subsystem, and a handheld body. The control system can include a battery-operated power supply and a user-operable control. The heating element extends along the insulator. The control system electrically energizes the heating element during system operation. The air supply subsystem directs a flow of air along the heating element during system operation. The fog fluid supply supplies fog fluid to the flow of air. The heating element vaporizes the fog fluid, which is emitted from an end of the system.

Description:
BACKGROUND 
     A fog machine is a device that emits a stream or puff of visible vapor or fog for theatrical or similar purposes. The effect can be enhanced by projecting light through the emitted fog to provide a dramatic visual effect on stage, in a dance club, etc. A fog machine operates by pumping a non-toxic fog fluid, such as glycol, glycerine, or a water-based mixture thereof, into an airstream and past a heating element. The airstream is typically provided by a fan. The heating element causes the fluid to vaporize, producing a visible vapor or fog. 
     Fog machines are typically portable but not especially compact, generally having a boxy shape with a size on the order of that of a small suitcase or briefcase and weighing on the order of 5-10 pounds (2.25-4.5 kilograms) or more. Most fog machines are powered by utility power, i.e., they must be plugged into a wall outlet, portable generator or similar source of utility-level power. Accordingly, fog machines are typically brought to an unobtrusive location in a corner of a theater stage or other location where a performance or other activity is to take place, left in place throughout the activity, and used at times during the activity to produce fog. Compact, battery-powered fog machines have been developed, but remain uneconomical due to complex, specialized parts. 
     SUMMARY 
     Embodiments of the present invention relate to a system for generating fog effects. An exemplary system can include a control system, a fog fluid reservoir, an elongated insulator, an elongated electric heating element, an air supply subsystem, a fog fluid supply subsystem, and a handheld body. 
     The control system can include a battery-operated power supply and a user-operable control such as a switch. The control system initiates system operation at least in part in response to the user-operated control. The heating element extends along the insulator and is coupled to the control system. The control system electrically energizes the heating element during system operation. The air supply subsystem is coupled to the control system and directs a flow of air in a direction along the heating element from an intake end toward an exhaust end during system operation. The fog fluid supply subsystem is coupled to the fog fluid reservoir and the control system, and supplies fog fluid to the flow of air during system operation. 
     The handheld body has an opening substantially adjacent to the exhaust ends of the heating element and insulator and contains the battery-operated power supply, the fog fluid reservoir, the insulator, the heating element, the air supply subsystem, and the fog fluid supply subsystem. In some embodiments, the body can also be elongated and resemble an object that characteristically burns, such as torch, cigar, etc. In this manner the handheld fog effects system can be used as an acting prop, toy or similar device. 
     Other systems, methods, features, and advantages of the invention will be or become apparent to one of skill in the art to which the invention relates upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are encompassed by this description and the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention can be better understood with reference to the following figures. The elements shown in the figures are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. Also, in the figures like reference numerals designate corresponding elements throughout the different views. 
         FIG. 1  is a block diagram of a fog effects system, in accordance with an exemplary embodiment of the invention. 
         FIG. 2  is a side elevation view of a portion of the fog effects system of  FIG. 1 . 
         FIG. 3  is a sectional view taken on line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a sectional view taken on line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a side elevation view of the exemplary fog effects system of  FIG. 1 . 
         FIG. 6  is a similar to  FIG. 5 , showing another side of the exemplary fog effects system. 
         FIG. 7  is a side elevation view of the exemplary fog effects system of  FIG. 1 , housed in a body resembling a torch. 
         FIG. 8  is a side elevation view of the exemplary fog effects system of  FIG. 1 , housed in a body resembling a cigar. 
     
    
    
     DETAILED DESCRIPTION 
     As illustrated in  FIG. 1 , in an illustrative or exemplary embodiment of the invention, a fog effects system comprises a fog generator system  10  that includes a heating element  12 , an insulator  14 , a fog fluid reservoir  16 , an air pump  18 , and a liquid pump  20 . Fog generator system  10  further includes a battery-operated power supply  22  that includes one or more batteries and associated electrical connectors or other power supply elements. Power supply  22  can employ, for example, four AA-size (1.5 volt) batteries connected in series with each other to produce 6 volts. Fog generator system  10  also includes two user-operable switches  24  and  26  or similar controls. In this exemplary embodiment, power supply  22 , switches  24  and  26  and associated electrical connections can together define a control system. However, in other embodiments control systems can include additional or different electronic or mechanical elements. Similarly, although in the exemplary embodiment air pump  18  and associated electrical, pneumatic and mechanical connections (described below in further detail) can define an air supply subsystem, and liquid pump  20  and associated electrical, fluid and mechanical connections (described below in further detail) can define a fog fluid supply subsystem, in other embodiments air supply subsystems and fog fluid supply subsystems can include additional or different electronic, fluid, pneumatic, mechanical, etc. elements. For example, in an alternative embodiment (not shown) the air supply subsystem can include a controllable valve, vane, flap, etc. for directing the flow of air, instead of or in addition to energizing the air pump. Similarly, the fog fluid supply subsystem can include other such controllable elements. Alternatively to being controllable, in some embodiments such elements can be fixed or otherwise passive. Also, in such other embodiments, the liquid pump, air pump, or both can be operated manually rather than electrically. Indeed, in some embodiments, one of the fog fluid supply subsystem and the air supply subsystem need not include a pump at all. Rather, for example, the fog fluid supply system can produce a stream of fog fluid that is sufficiently atomized without the use of an air pump. Also, in other embodiments, the control system and elements that it controls can be configured to cause the fog to be emitted in a specific pattern or other manner, such as in a puff of predetermined duration, a series of puffs, a continuous stream, a pseudo-random manner, or any other desired manner, to create any desired effect. 
     In the illustrated embodiment, when a user closes switch  26 , which can be, for example, a miniature slide switch, heating element  12  is electrically coupled to battery-operated power supply  22  and therefore energized. When energized, heating element  12 , which can be, for example, a nickel-chromium or nichrome resistance wire, quickly becomes hot. Then, when a user closes switch  24 , which can be, for example, a momentary-contact pushbutton switch, air pump  18  and liquid pump  20  are each electrically coupled to battery-operated power supply  22  and therefore energized. Air pump  18  can be any suitable pump that can deliver a flow of air, such as a diaphragm pump. When energized, air pump  18  pumps air into an intake end of insulator  14 , which can be, for example, a hollow tube made of ceramic, glass or similar heat-insulating material. Liquid pump  20  can be any suitable pump that can deliver a liquid in a controlled manner, such as a peristaltic pump. When energized, liquid pump  20  pumps fog fluid from fog fluid reservoir  16  into the flow of air or airstream at the intake end of insulator  14 . Heating element  12  is aligned along insulator  14  and has an intake end corresponding to the intake end of insulator  14  and an exhaust end corresponding to the exhaust end of insulator  14 . At the intake ends of heating element  12  and insulator  14 , the heat emitted by heating element  12  begins to vaporize the fog fluid that is carried in the air stream. The vaporization continues as the fog fluid is conveyed through the airstream along the length of heating element  12  and insulator  14  toward the exhaust ends of heating element  12  and insulator  14 . The vapor or fog is emitted at the exhaust ends of heating element  12  and insulator  14 , as indicated by the arrow  28 . 
     The fog effects system can also include an illumination system  30  to illuminate the fog emanating from fog generator system  10  for an added dramatic effect. Illumination system  30  can comprise one or more electrical lighting elements, such as light-emitting diodes (LEDs)  32  (only one of which is shown in  FIG. 1  for purposes of clarity, but several are connected together in parallel in the exemplary embodiment), and a lighting controller  34 . Lighting controller  34  controls the operation of LEDs  32  by, for example, causing them to flash in a manner that provides a flickering effect that evokes an appearance of flames or fire. Lighting controller  34  can include, for example, a programmable interface controller (PIC) device, which is a well-known device that is commercially available from a variety of sources. As persons skilled in the art understand how PIC devices are programmed and connected, these aspects are not described herein. The LEDs  32  can include a combination of red, amber and white or other colored LEDs that emit colors resembling those of fire, and lighting controller  34  can cause the various colors to alternately flash in a manner that resembles the changing colors of a flickering fire. Although not shown for purposes of clarity, lighting controller  34  is coupled to an output of the above-described control system of fog generator  10  that includes switch  24  so that when a user presses switch  24  lighting controller  34  activates LEDs  32  to illuminate the emitted fog. Although in the exemplary embodiment lighting controller  34  of illumination system  30  is somewhat separate from the control system of fog generator  10 , in other embodiments the lighting control functions and fog generator control functions can be integrated or combined with each other using, for example, a single PIC device or similar controller to control these functions and others. 
     As illustrated in  FIGS. 2-4 , an air hose  36  delivers air from air pump  18  to a coupling tube  38 , which is connected to the intake end of the (tubular) insulator  14 . Similarly, a liquid hose  40  delivers fog fluid from liquid pump  20  to coupling tube  38 . In the exemplary embodiment, heating element  12  has a helical shape and is disposed within insulator  14 , as best shown in  FIG. 2 . Insulator  14  can be made of a suitable heat-insulating material, such as ceramic. Insulator  14  is, in turn, disposed within an outer tube  42  and held in place by a retaining tube  44 . Retaining tube  44  has a flattened or elliptical cross-sectional shape that squeezes or holds insulator  14  centered within retaining tube  44 . Although in other embodiments (not shown) an insulator can be retained in any other suitable manner, such as by one or more spacers (not shown) extending between the insulator and the outer tube or similar outer structure, the flattened tube of the exemplary embodiment provides the retaining function in a manner that can be economically manufactured from readily available metal tubes. Outer tube  42  and retaining tube  44  can be made of economical but durable materials such as aluminum or brass. The heat-insulating property of insulator  14  and the air gaps between insulator  14  and retaining tube  44  and between retaining tube  44  and outer tube  42  insulate outer tube  42  against becoming unsafely or uncomfortably hot, thereby facilitating use of the fog effects system as part of a toy, prop, costume, etc., worn or held by a person. Although tubes  42  and  44  are metal tubes in the exemplary embodiment, in other embodiments (not shown) analogous structures can have any other suitable shapes and compositions. Although in the exemplary embodiment outer tube  42  serves as one of the electrical conductors for powering heating element  12  (as described below in further detail), in embodiments (not shown) in which the tubes or other structures are made of a non-conductive material, a separate electrical conductor can be included. 
     A first clamp-like ring terminal  46  can be attached to coupling tube  38  to electrically couple one side or polarity output, e.g., a positive polarity output, of the above-described control system to heating element  12 . The proximal end (i.e., intake end) of heating element  12  can be electrically coupled to coupling tube  38  by, for example, friction-fitting it within a groove-like indentation  48  in coupling tube  38  between the outer wall of coupling tube  38  and the inner wall of insulator  14 , as best shown in  FIG. 3 . A second clamp-like ring terminal  50  can be attached to outer tube  42  to electrically couple the other side or polarity output, e.g., a negative polarity output, of the above-described control system to heating element  12 . The distal end (i.e., exhaust end) of heating element  12  can be electrically coupled to retaining tube  44  by, for example, friction-fitting it within a groove-like indentation  52  in retaining tube  44  between the outer wall of retaining tube  44  and the inner wall of outer tube  42 , as best shown in  FIG. 3 . 
     In operation, liquid pump  20  pumps fog fluid from fog fluid reservoir  16  into the airstream produced by air pump  18 . The hot heating element  12  vaporizes the fog fluid as the fog fluid suspended in the airstream migrates along the length of heating element  12  from its proximal or intake end toward its distal or exhaust end. The relatively long region in which the fog fluid suspended in the airstream can absorb the heat emitted by heating element  12  promotes complete vaporization despite the relatively low voltage (for example, 6 volts) applied to heating element  12  by battery-operated power supply  22 . 
     A frusto-conical nozzle  54  having an exhaust opening  56  is attached to the distal end (i.e., exhaust end) of outer tube  42 , with exhaust opening  56  adjacent to the exhaust ends of heating element  12  and insulator  14 . In operation, the fog effects system emits the vapor or fog through exhaust opening  56 . 
     As illustrated in  FIGS. 5-6 , fog generator system  10  and illumination system  30  can be mounted within a body  58 . Switches  24  and  26  can be mounted in walls of body  58  to facilitate their operation by a user (not shown). The LEDs  32  of illumination system  30  can be mounted around the periphery of a ring  60  near nozzle  54 . A perforated disk  62  can be mounted adjacent nozzle  54  to aid dispersing or inducing laminar flow of the vapor or fog. Similarly, a grating  64 , which can have hexagonal openings (not shown) arrayed in a honeycomb fashion, can similarly aid dispersing the vapor or fog. A user can fill fog fluid reservoir  16  through a removable cap  59 . 
     Body  58  is shown in broken line in  FIG. 5  to indicate that it need not have the indicated cylindrical shape. Rather, body  58  can have a shape that resembles an object that characteristically burns, such as the torch shape shown in  FIG. 7  or the cigar shape shown in  FIG. 8 . An actor, for example, can hold a fog effects system having a torch-shaped body  58  in his hand and use it as a prop to simulate a burning torch. Note that switch  24  is mounted in an orientation in or on body  58  that facilitates button  24  to be actuated by the user&#39;s finger in a trigger-like manner when the user (not shown) is gripping body  58 . When the actor or other user presses button  24 , the fog effects system emits a stream of fog and generates flickering light. The simulated smoke and the flickering light combine to create an effect that is evocative of the fire in a torch. 
     Similarly, an actor can hold a fog effects system having a cigar-shaped body  60  in his hand and use it as a prop to simulate a burning cigar. When the actor or other user presses switch  24 , the fog effects system emits a puff of fog and generates a glowing light. The simulated smoke and glowing light combine to create an effect that is evocative of a burning cigar. In view of these descriptions, persons skilled in the art can readily provide fog effects systems having bodies with other shapes that simulate or resemble any other such hand-held objects that are characteristically used in a burning state. 
     It should be noted that embodiments in which operation is initiated in a trigger-like manner especially lend themselves to the inclusion of a manually operated or otherwise non-electrically-operated fog fluid supply subsystem, air supply subsystem, or both. For example, a manually operated fog fluid pump (not shown) can have a trigger resembling button  24  shown in  FIG. 5 . The force that the user&#39;s finger applies to the trigger operates the fog fluid pump. 
     Furthermore, in other embodiments (not shown) one of the fog fluid supply subsystem and the air supply subsystem can operate more passively than the other. For example, in some embodiments the fog fluid introduced by the fog fluid supply subsystem is flash-vaporized so rapidly that as it changes from a liquid to a gas the expanding gas creates such a sufficient flow of the vapor out of the exhaust end that no air pump is needed. In such embodiments the air supply subsystem serves to passively direct the flow. It should be noted that although in the embodiment described above both the fog fluid supply subsystem and air supply subsystem are electrically operated (i.e., both air pump  18  and a liquid pump  20  are electrically operated), in other embodiments neither the fog fluid supply subsystem nor the air supply subsystem need be electrically operated. For example, the fog fluid pump can be manually operated, and the air supply subsystem can operate passively, directing the expanding vapor out the exhaust end. 
     While one or more embodiments of the invention have been described as illustrative of or examples of the invention, it will be apparent to those of ordinary skill in the art that other embodiments are possible that are within the scope of the invention. Accordingly, the scope of the invention is not to be limited by such embodiments but rather is determined by the appended claims.