Abstract:
An apparatus and system that efficiently and effectively delivers a sanitizing fluid to ducts in the form of a fog or mist is described. A canister that contains a liquid sanitizing solution is attached to a compressor and includes a straw that has an internal passageway that extends into the liquid and a venturi tube above the level of the liquid that connects with the internal passageway in the straw. The headspace above the liquid in the canister is pressurized, causing fluid to flow upwardly in the straw when a trigger is depressed, drawing fluid upwardly in part by the venturi. As the liquid passes the venturi the pressurized air that is flowing into the venturi causes the fluid to form a fine mist. The mist, under pressure from the compressor, is routed into a flexible delivery tube that has been previously positioned in a duct system. The terminal end of the tube has an atomizing ball attached thereto and the atomizing ball has a series of orifices through which the misted, atomized fluid is delivered. As fogged sanitizing solution flows through the orifices it is deposited on the interior surfaces of the duct. The delivery tube and the attached atomizing ball are withdrawn from the duct as the sanitizing fog is emitted from the ball. The fan in the HVAC system is not activated so there is no deliver of the sanitizer through registers and into the living space. The apparatus and method may be used to apply other fluids to other surfaces.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an apparatus and method for applying fluid such as sanitizing fluid to ducts and the like, and more specifically to an apparatus that delivers a sanitizing solution in the form of a fog or mist to the interior of ducts such as those in HVAC systems. 
       BACKGROUND 
       [0002]    Ducts such as those found in HVAC systems in both commercial and residential settings often require cleaning. There are several known and well-established ways to clean ducts, for example, vacuum systems, rotating brushes to air-jet systems, and combinations of these. Described briefly, a cleaning system is intended to remove dust and debris from the interior of ductwork so that these materials are not blown into the structure by the fans that move air, both heated and cooled, through the ducts. As would be expected, ducts are a collection point for all sorts of detritus, everything from dust, mold and mildew to rodents and their droppings. Maintaining ducts in a clean state is very important to prevent detritus from the ducts being blown into the structures that the ducts supply hot and cold air to. This is especially true as the incidence of health problems associated with airborne particulate matter, such as various forms of asthma, seem to be on the increase. 
         [0003]    As would also be expected, especially in view of the fact that ducts can be infested with rodents, sanitizing ducts after they have been cleaned can be an important maintenance procedure. Conventionally, sanitizing is accomplished by introducing a mist of a sanitizing solution into the cold air return vent of a ducting system while the fan (such as a furnace fan) is operating. The fan draws/pushes the mist through the ducts and the sanitizing solution is thus deposited on the interior surfaces of the ducts. But a drawback of this technique is that for the fan to draw/push the sanitizing mist through the entire system, the registers through which air is delivered into the living spaces must be left open. As a result, most of the sanitizing mist is pushed into the living space where it collects on surfaces. This can be a detriment in a variety of ways, from off odors to health issues. 
         [0004]    There is a need therefore for an apparatus and methods for sanitizing ductwork. 
         [0005]    The invention described herein and illustrated in the drawings defines an apparatus and system that efficiently and effectively delivers a sanitizing compound to ducts while avoiding problems associated with known systems. While the invention is described an illustrated in a preferred embodiment with respect to applying sanitizing fluid to HVAC ducts and the like, it will be appreciated that the principles of the invention and the components may be used to apply other liquids to other surfaces. As such the invention is not limited to sanitizing fluid applied to ductwork but is limited only by the appended claims. 
         [0006]    The present invention is defined by a canister that contains a liquid sanitizing solution and which includes a trigger. The canister is attached to a compressor and includes a straw that has an internal passageway that extends into the liquid and a venturi tube above the level of the liquid that connects with the internal passageway in the straw. When the trigger is actuated, the headspace above the liquid in the canister is pressurized, causing fluid to flow upwardly in the straw, drawing upwardly in part by the venturi. As the liquid passes the venturi the pressurized air flat is flowing into the venturi causes the fluid to form a fine mist. The mist, under pressure from the compressor, is routed into a flexible delivery tube that has been previously positioned in a duct system. The terminal end of the tube has an atomizing ball, also called a misting ball, attached thereto and the atomizing ball has a series of purposefully and specifically oriented orifices through which the misted, atomized fluid is delivered. As fogged or misted sanitizing solution flows through the orifices it is deposited on the interior surfaces of the duct. The delivery tube and the attached atomizing ball are withdrawn from the duct as the sanitizing fog is emitted from the ball. The fan in the HVAC system is not activated so there is no deliver of the sanitizer through registers and into the living space. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings. 
           [0008]      FIG. 1  is a perspective view of a complete apparatus according to the present invention for sanitizing ducts. 
           [0009]      FIG. 2  is perspective view of an exemplary embodiment of a canister for use with the apparatus shown in  FIG. 1 . 
           [0010]      FIG. 3  is a perspective view of three primary components of the apparatus according to the present invention shown in  FIG. 1 , and more specifically,  FIG. 3  shows the canister with its trigger head assembly separated from the canister, and the atomizing ball. 
           [0011]      FIG. 4  is a perspective view of part of the canister shown in  FIG. 2  and illustrating in phantom lines the interior components of the apparatus, and more particularly, the straw that is part of the trigger head assembly. 
           [0012]      FIG. 5  is a perspective view of the trigger head assembly shown in isolation. 
           [0013]      FIG. 6  is a cross sectional view of one preferred embodiment of an atomizing ball according to the present invention. 
           [0014]      FIG. 7  is an elevation view taken along the line  7 - 7  of  FIG. 6 . 
           [0015]      FIG. 8  is a perspective view of the atomizing ball shown in  FIGS. 6 and 7 . 
           [0016]      FIG. 9  is a schematic plan view of a representation of a floor plan of a house or other structure that utilizes a HVAC of the type that may be sanitized with the apparatus according to the present invention. 
           [0017]      FIG. 10  is a perspective view of the canister according to the present invention illustrating use of the apparatus. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    The invention and its method of use will now be described in detail with reference to the drawings. It will be understood that relative directional terms are used at times to describe components of the invention and relative positions of the components. As a naming convention, the ground plane or the plane of a floor in a structure is considered to be a generally horizontal surface. Other relative directional terms correspond to this convention: “upper” refers to the direction above and away from the floor plane; “lower” is generally in the opposite direction, “inward” is the direction from the exterior toward the interior of the apparatus, “vertical” is the direction normal to the horizontal floor plane, and so on. 
         [0019]    With reference now to  FIG. 1 , apparatus  10  according to a first illustrated embodiment comprises three primary components: a canister  20 , a delivery tube  80  and an atomizing ball  100 . Each of these basic components is shown in the various drawings and will be described in detail, both structurally and functionally, below. 
         [0020]    Canister  20  is shown in detail in  FIGS. 1 through 4 . It includes a quick connect fitting  22  that is a conventional pressure fitting for connecting the canister to a conventional air compressor and which defines a port for compressed air from the air compressor to pressurize the canister. The air compressor and the tubing that connects it to the canister  20  at quick connect fitting  22  are not shown in the drawings because they are entirely conventional and form no part of the invention. And while the quick connect fitting  22  shown in  FIG. 1  extends away from the canister  20  at approximately a right angle relative to a vertical axis, it will be appreciated that the quick connect may be oriented at an angle, such as a 45 degree downward angle, to make the connection to the compressor easier from an ergonomic perspective. Nominally, the air compressor is operated at a pressure sufficient to generate a fine mist or to atomize the sanitizing fluid. As used herein, the terms “mist” and “atomized” fluid refer to a fluid that in the form of fine, small droplets. In operation, 200 psi is sufficient. Of course, all components in the system that are pressurized must be specified for safe operation at normal operating pressures. 
         [0021]    Canister  20  is shown in isolation in  FIG. 2 . The canister  20  comprises a bottle  24  that defines a reservoir for containing a supply of liquid sanitizing solution. A trigger head assembly  26  is threaded onto the threaded opening  28  at the upper end of bottle  24  and includes a handle  30 , a trigger  32 , a head  34  and an outlet connection  36 . The delivery tube  80  (described below) connects to the outlet connection  36  of the trigger head assembly  26  to the atomizing ball  100  and provides a fluid pathway from the bottle  24  to the atomizing ball. The connection illustrated in  FIG. 2  between delivery tube  80  and outlet connection  36  is a threaded connection, but a quick connect fitting such as quick connect  22  used on canister  20  may be substituted. 
         [0022]      FIG. 3  shows the canister  20  and its component parts in a disassembled view, namely, where the trigger head assembly  26  and delivery tube  18  are shown in isolation. Trigger head assembly  26  has a threaded boss  38  that threads into threaded opening  40  in the upper end of bottle  24 . An O-ring  42  on a shoulder  39  of boss  38  provides a fluid tight seal between trigger head assembly  26  and bottle  24  when the trigger head assembly  26  is threaded into bottle  24  and canister  20  is pressurized by the air compressor. A straw  44  extends downwardly from trigger head assembly  26  and through boss  38 . As detailed below, the distal end  46  of straw  44  is immersed in the sanitizing fluid contained in bottle  24  during operation of apparatus  10  and the fluid is pushed/drawn upwardly through a passageway through the straw for delivery into the delivery tube  80 . 
         [0023]    Reference is now made to  FIG. 4 , which is a partial schematic representation of bottle  24  to illustrate better the straw  44 . In  FIG. 4 , the dashed line  48  represents the level of sanitizing fluid contained in the bottle  24  when the bottle is in a full condition. The distal end  46  of straw  44  is below the headspace  50  defined as the air space over the fluid level, dashed line  48 . A fluid passageway  52  extends completely through straw  44  from the inlet  54  at distal end  46  and extending through the straw at its connection at the proximate end  56 , which is connected to a fluid passageway within head  34 . The nominal diameter of fluid passageway  52  is approximately 9 mm. Above the fluid level  48 , in headspace  59 , is a venturi tube  58  that defines a passageway from the outer wall of straw  44  that connects to fluid passageway  52 . Ideally, venturi tube  58  is angled downwardly relative to passageway  52  at about a 45 degree angle, as shown. The nominal diameter of venturi tube  58  is about 9 mm. 
         [0024]    The proximate end  56  of straw  44  is connected to an internal fluid passageway (not shown) in head  34  that fluidly communicates with outlet  36 . Trigger  32  is operable to open and close the fluid passageway and to vary the degree of openness of the passageway. 
         [0025]    With returning reference to  FIG. 1 , the delivery tube  80  defines a fluid passageway extending from the trigger head assembly  26  to the atomizing ball  100 . More specifically, pressurized and at least partially atomized fluid flows through delivery tube  80  when the canister  20  is pressurized and trigger  32  is actuated to open the fluid passageway through trigger head assembly  26  and to thereby cause a flow of fluid to move through the apparatus. The proximate end  82  of delivery tube  80  is attached to outlet  36  of trigger head assembly  26 , as noted above with a quick connect fitting or with a screw fitting as shown in the figures. The distal, terminal end  84  of delivery tube  80  is attached to atomizing ball  100 . The attachment of tube  80  to ball  100  may be in any appropriate manner, for example, with a threaded connection shown generally at reference number  86 . The material used for delivery tube  80  is preferably flexible so that the tube and the attached atomizing ball may be easily maneuvered through the various turns found in common ducting systems. The tube preferably has sufficient longitudinal rigidity that it may be pushed into a duct, as detailed below. A suitable hose is a polyurethane reinforced type of tube, and of course the tube must be of the type that is capable of being used at the operating pressures for the apparatus. The length of tube  80  will vary on the particular use, but is preferably long enough that the tube is able to reach from the introduction point of the tube in the duct system to the furthest most point that is to be sanitized, as detailed below. 
         [0026]      FIG. 5  is a relative close up view of the distal end of the straw  44 , showing inlet  54 , and also illustrating and the attachment of the proximal end  56  of straw  44  to the trigger head assembly  26 . 
         [0027]      FIG. 6  is a cross sectional view through one preferred embodiment of atomizing ball  100 . An inlet  102  in ball  100  is threaded. The distal end  84  of delivery tube  80  threads into the threaded inlet  102 , as noted above with a threaded fitting  86 . The diameter of inlet  102  is nominally ⅛ inch, although this may be varied. The inlet  102  defines a chamber  104  in ball  100  that preferably has the same diameter as inlet  102  and into which sanitizing fluid is delivered under pressure from delivery tube  80 . There are plural outlets formed in atomizing ball  100  that communicate with chamber  104  and which define outlet orifices so that fluid flowing into the chamber  104  is ejected through the orifices. The outlet orifices have a smaller diameter than the inlet  102  and chamber  104 . The outlets define fluid pathways from the inlet  102  and chamber  104  so that fluid flowing into the chamber may be ejected under pressure from the atomizing ball  100 . The number, arrangement, angular orientation and spacing of the outlets may be varied; those shown in  FIG. 6  are exemplary but not limiting. As seen in  FIG. 6 , there six outlets labelled with reference number  110 , and six outlets labelled with reference number  112 . The outlets  110  are relatively evenly radially spaced around the outer surface of ball  100  and are angularly oriented relative to the longitudinal axis L defined by inlet  102 . More particularly, the six outlets  110  are angled in the direction back toward the point where delivery tube  80  is attached to inlet  102 . The angular displacement of the outlets  110  is preferably between about 20 and 45 degrees from a line normal to the longitudinal axis L, but the angle may vary according to need. The six outlets labelled with reference number  112  also extend at an angle relative to the longitudinal axis L defined by inlet  102 , and most preferably, at an angle between about 20 and 45 degrees. However, as shown in  FIG. 6 , the outlets  112  are angled in the opposite direction of the outlets  110 , toward the forward end of ball  100 . 
         [0028]    Turning now to  FIG. 7 , which is a view taken along the line  7 - 7  of  FIG. 6 , there twelve separate outlet orifices  110  and  112  arranged at equal radial intervals around inlet  102 , and the six outlets  110  are radially staggered relative to the six outlets  112 . The twelve outlet orifices are equally spaced around the inlet  102  in an annular array, meaning that there is an arc of about 60 degrees between adjacent orifices  110  and the same arc between adjacent orifices  112 . The number of outlet orifices and their spacing and angular orientation relative to the axis of inlet  102  may be varied widely. 
         [0029]    Ball  101  is preferably made from a durable plastic or similar material such as nylon. 
         [0030]      FIG. 8  is one embodiment of an atomizing ball  100  attached to a delivery tube  80  with a threaded fitting  86 . 
         [0031]    Operation of apparatus  10  will now be detailed with particular reference to the schematic drawing of  FIG. 9 , which is a representation of a floor plan of a structure that utilizes an HVAC system. Specifically, with reference to  FIG. 9 , the structure&#39;s foundation perimeter is shown at  150 . An air-moving apparatus  145 , such as a furnace, heat pump and the like is a conventional HVAC unit that includes a fan (not shown) and which includes a cold air return  154  that has a conventional in-structure cold air return vent  155 . The main duct line  156  extends from the furnace  145  and includes plural branch ducts that each terminates in a register. Specifically, the branch ducts are labelled with reference numbers  160   a ,  160   b ,  160   c ,  160   d ,  160   e ,  160   f , and  160   g . Each of these branch ducts terminates at a register; the registers are labelled to correspond with the labeling convention used for the branch ducts, thus,  162   a ,  162   b ,  162   c ,  162   d ,  162   e ,  162   f , and  162   g.    
         [0032]    In order to sanitize the branch ducts  160  and the main duct  156 , sanitizing fluid is filled into canister  20  to the level shown in  FIG. 4  and identified with reference number  48 . With delivery tube  80  disconnected from canister  20  at outlet  36 , the atomizing ball  100  is inserted into a register opening (the register grate is removed first) and the ball and tube  80  are threaded into the branch duct a few feet. For example, with reference to  FIG. 9 , the sanitizing operation could begin at register  162   f . The register grate is removed and the ball  100  with attached tube  80  is inserted through the register opening and into branch duct  160   f . The ball  100  and tube  80  may be inserted into a duct such as duct  160   f  in several different ways. In a first preferred method the operator simply snakes the ball and tube into the ducting system by pushing on the tube, which is flexible but axially and longitudinally rigid enough that it may be slid into the duct fairly easily. Another method involves use of attaching the proximate end of the tube  80  to an air compressor and using air blown through the outlet orifices in ball  100  to aid pushing the ball and tube into the duct. With the ball  100  inserted a few feet into the duct, the air compressor is pressurized to the desired operating pressure and the proximal end  82  of delivery tube  80  is connected to the air compressor. This pressurizes the tube  80  and pressurized air is immediately expelled through the outlet orifices in atomizing ball  100 . There are twelve outlet orifices  110  and  112  in the ball  100  shown in  FIGS. 6 and 7 , six of which are angled back toward the inlet  102  and thus the register  162   f  as the ball  100  and tube  80  are snaked into the branch duct  160   f . As such, the high-pressure air that is expelled through the six backward oriented outlet orifices (i.e., orifices  110 ) propel the atomizing ball  100  and the trailing delivery tube  80  along the branch duct  160   f , with assistance provided by the technician pushing the delivery tube into the branch duct, and into the main duct  156 . Although the air expelled through orifices  112  is in an angularly opposed direction relative to the air expelled through orifices  110 , the combination of the air expelled from the six orifices  110  and the pushing force provided by the technician overcomes the force of the air expelled through orifices  112 . As such, the ball  100  is easily jetted along main duct  156  to the primary T-branch  164  shown in  FIG. 9 . Depending upon the design of the various ducts, the ball  100  may be propelled/pushed even around tight corners. At this point with the atomizing ball  100  in the desired location in the duct system, the air compressor is disconnected from delivery tube  80 . 
         [0033]    When the ball  100  is in the desired position, regardless of which method described above is used to deliver the ball to that position, the proximal end of delivery tube  80  is next attached to outlet  36  of trigger head assembly  26  of canister  20  (which has been filled with sanitizing fluid and attached to the trigger head). The pressurized line from the air compressor is then attached to canister  20  at quick connect fitting  22 . Trigger  26  may then be actuated. 
         [0034]    As soon as the trigger  26  is actuated, the headspace  50  above liquid level  48  in canister  20  is pressurized. This creates a high pressure in the headspace, which drives liquid upwardly in passageway  52  of straw  44 . As detailed earlier, the liquid is at least partially atomized at venturi  58  and the mist is pushed through delivery tube  80  and out of the twelve outlet orifices in the atomizing ball  100 . The size of the orifice openings causes the already at least partially atomized sanitizing fluid to become completely atomized into a very fine mist that is ejected at a high velocity out of the orifices. The mist is thoroughly applied to the interior surfaces of the duct with very complete coverage. 
         [0035]    As would be expected, the jetting of atomized sanitizing fluid through the orifices may tend to drive ball  100  away from its origin point at register  162   f . Therefore, the operator slowly pulls on delivery tube  80  to pull ball  100  back through the main duct  156  and then through branch duct  162   f  as the trigger  32  remains depressed. As the ball is withdrawn, the fine droplets of sanitizing fluid expelled out of the outlet orifices  110  and  112  completely and thoroughly coat the interior surfaces of the duct with the mist. The speed at which the tube is withdrawn affects the amount of sanitizing liquid applied to the ducts. And as noted above, the trigger  32  is a variable opening trigger—the further that the trigger is moved from closed toward fully open, the more sanitizing fluid that flows through the system. 
         [0036]    When the atomizing ball  100  reaches register  162   f  the trigger  32  is released and the flow of sanitizing fluid immediately stops—the headspace  50  is immediately depressurized. The operator may then remove ball  100  and delivery tube  80  and move to another register to sanitize the next duct or ducts. It will be appreciated that the operator will be required to work his or her way around the structure in order to sanitize all of the various ducts. 
         [0037]    Using the apparatus and method described above and as shown in the drawings, the entire duct system of a structure is very thoroughly sanitized and the atomized or misted sanitizing fluid is not expelled into the living space. If desired, during sanitization of one set of ducts, other registers in the structure may be closed to insure that sanitizer does not flow into the living space. In addition, it will be recognized that use of the invention is not limited to sanitizing fluids applied to HVAC ducts, but may be used with other fluids that are to be applied to tubing, such as sealers, deodorizers, etc. applied to virtually any type of elongate enclosed space. 
         [0038]    Finally,  FIG. 10  illustrates the manner in which an operator holds canister  20  to operate trigger  32  to operate the apparatus  10 . The canister and trigger head assembly  26  and trigger  30  are ergonomically designed to make the system easy to handle 
         [0039]    While the present invention has been described in terms of preferred and illustrated embodiments, it will be appreciated by those of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.