Abstract:
A portable inflatable heating, ventilating and air conditioning duct apparatus includes a bladder made of resilient material for expansion and contraction. The bladder has a small opening for the movement of air in and out of the bladder. An elongate flexible hose is connected at one end with the small opening on the bladder. An air pump is positioned at the opposing end of the elongate flexible hose for supplying air under low positive pressure to the bladder for expansion of the bladder. A manually operated valve is positioned between the air pump and the bladder for preventing the escape of air from the bladder, unless same is desired. The apparatus further includes direction stabilizing apparatus for allowing the flexible hose to push the bladder through a segment of the HVAC duct in which the apparatus is positioned.

Description:
This invention relates generally to heating and ventilating air duct cleaning apparatus, and more particularly, to a low pressure duct cleaning apparatus including a bladder that when inflated contacts the interior surface of heating and ventilating (HVAC) ducts to wipe clean same as the bladder is moved along the length of the duct. 
     BACKGROUND OF THE INVENTION 
     Presently, complex duct cleaning systems include vacuum pressurized pneumatic lines, pressurized fluid spraying lines and pneumatically operated whirling brushes. The fluid or air under pressure and the whirling brushes loosen dust, dirt and grime, and a vacuum line is supposed to pick up the residue. So-called advances in these systems have included making them more complex with additional optional equipment. 
     German Patent 162130 discloses a flue cleaner having a rectangular metal frame with an expansible rubber outer surface for scraping against the rectangular sides of a flue. 
     U.S. Pat. No. 856,063 discloses an expansible pipe cleaner having a rubber bladder that may be flattened and made to a larger diameter by screwing a nut along a central rod to expand the diameter of the bladder. The patent also discloses a ribbed outer surface for the bladder. 
     U.S. Pat. No. 5,285,806 discloses an inflation bag which when used with a retaining rod positioned diametrically across a pipe line in conjunction with a high pressure source of compressed gas will block a pipeline from fluid flow therethrough. 
     A need has developed for an improved simplified apparatus for cleaning heating, ventilating and air conditioning ducts. 
     Additionally, a need has developed for providing an improved simplified apparatus for cleaning ducts which is capable of cleaning both rectangular and circular HVAC ducts. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a portable inflatable HVAC duct cleaning apparatus comprising a bladder made of resilient material for expanding and contracting its size. The bladder has a small opening for moving air in and out thereof. An elongate flexible hose is positioned in communication with the small opening on the bladder. An air pump is positioned in fluid communication at an opposing end of the elongate flexible hose for supplying air under low positive pressure to the bladder when expanding the bladder. Manually operable valve means are positioned between the air pump means and the bladder for preventing the escape of air from the bladder as desired. Direction stabilizing means are included and are positioned in communication with the hose for aiding and positioning the bladder a substantial distance from any opening in any HVAC duct in which the apparatus is positioned. 
     The invention is further directed to a method of cleaning a segment of an HVAC duct which comprises the following steps: 
     1) depositing cleaning fluid on the exterior of a resilient bladder; 
     2) positioning the resilient bladder inside an HVAC duct; 
     3) pushing the bladder and hose attachment into the HVAC duct; 
     4) inflating the bladder until its exterior substantially completely fills a cross section of the HVAC duct; 
     5) pulling on the hose to move the bladder along a segment of the duct loosening dirt and debris from the interior of that segment; 
     6) deflating the bladder, and cleaning the exterior of the resilient bladder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention which are believed to be novel are set forth with particularity in the attached claims. The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which like numerals refer to like parts, and in which: 
     FIG. 1 is a perspective view, with portions cut away, of a portable duct cleaning apparatus constructed in accordance with the present invention; 
     FIG. 2 is an enlarged fragmentary view of a bladder utilized in the present invention with portions cut away showing a wire coil extending therein for maintaining proper orientation of the bladder. 
     FIG. 3 is a fragmentary cross-sectional view of a bladder utilized in connection with the present invention showing a sponge type outer surface in connection therewith; 
     FIG. 4 is a fragmentary cross-sectional view of a bladder used in connection with the present invention showing a brush type exterior; 
     FIG. 5 is a fragmentary cross-sectional view of a bladder used in connection with the present invention showing a scrub pad type exterior positioned thereon; 
     FIG. 6 is a fragmentary view with portions cut away for clarity of the air hose utilized in the present invention showing the wire coil positioned therein for additional strength; 
     FIG. 7 is a front elevational view of a circular HVAC duct having the portable duct cleaning apparatus of the invention positioned therein with the bladder thereof shown in expanded position; 
     FIG. 8 is a cross-sectional view of a rectangular HVAC duct showing the duct cleaning apparatus of the invention positioned therein with the bladder in expanded position; 
     FIG. 9 is a cross-sectional view of a circular duct showing the expansible bladder showing the portable duct cleaning apparatus of the present invention completely filling the cross section of the duct. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a duct cleaning apparatus, generally indicated at  10 , constructed in accordance with the present invention, includes an expansible bladder  11  having a cleaning cloth or other exterior cover  12 , either mounted thereover or as an exterior surface of the bladder  11 , removably affixed to a pliable hose  13 . A selectably releasable collar  14  is positioned over the open end, the cover  12 , and the hose  13  and another collar  14 a is positioned over the open end of the bladder  11 . Hose  13  includes adjacent a distal end  13   a  thereof a shut off valve  15  which is hand operable by lever  16  between open and closed positions and the rigid tube  22 . The distal end  13   a  of hose  13  has connected thereto in the preferred embodiment a hand operable air pump  17 , sold by Unique Industries, Inc. as model 4920 which includes a manually holdable handle  18  and a reciprocable pump lever  18   a.  Adjacent the collar  14 , a multi-piece extensible positioning rod, generally indicated at  20 , is connected to hose  13  by means of a releasable collar  21 . In this embodiment, extensible rod  20  includes segments  20   a,    20   b  and  20   c  in this embodiment which provide an adjustable means for placing the bladder  11  and the cover  12  in the distant portion of a long straight duct to be cleaned. 
     Referring to FIG. 2, an enlarged cutaway view of the joinder of the hose  13 , bladder  11 , and extensible rod  20  discloses that adjacent and through the area of the joinder of those pieces is positioned a wire coil  23  that provides directional stability to the forward portion of the duct cleaning apparatus to assure the bladder does not kink or fold backward as the apparatus is being pushed through an HVAC duct. 
     Referring to FIG. 6, in the preferred embodiment of the invention, coiled wire or rod  23  extends through the length of hose  13  to provide additional directional stability for the hose  13  while allowing some resiliency thereto. Wire or rod coil  23  may be similar to a plumber&#39;s pipe cleaning rod. It should be noted that the wire or rod or coil  23  does not extend through the valve  15 , thus allowing it to be opened and closed freely. The valve  15  is positioned close to the distal end  13   a  of hose  13  to limit the amount of the hose that is not reinforced. Both the extensible rod  20  and the stability to the hose  13  and coil  23  may be more than one piece, if necessary, to extend into the bladder. Extensible rod  20  and coil  23  may be used together or separately as needed. 
     Referring to FIGS. 1,  3 ,  4  and  5 , several differing modifications to the bladder are shown having differing outside cleaning surfaces. Referring to FIG. 1, the bladder  11  has a cloth bag or cover  12  positioned thereover. The cloth cover  12  may be made of a cotton, burlap, terry cloth or other material that will provide a scrubbing surface for the outside of the bladder  11 . Referring to FIGS. 3,  4  and  5 , the bladder itself, shown at  11   a,    11   b  and  11   c  has integrally formed on the outside thereof a structure suitable for use in scrubbing the inside of an HVAC duct. FIG. 3 discloses an open cell sponge exterior  24  which is bonded to the outside of the bladder  11   a.  FIG. 4 shows brush bristles  25  that extend outwardly from the bladder  11   b.  FIG. 5 shows plastic scrub brush type interwoven fibers  26  that are integrally formed to extend from the outside of bladder  11   c.  All of the differing scrub surfaces  12 ,  24 ,  25  and  26  retain and support cleaning liquids (not shown) used in connection therewith for scrubbing the inside of HVAC duct surfaces. It should be noted that sponge  24  is expansible with the bladder  11   a,  as are the spaces between the bristles  25  of the brush on bladder  11   b  and the plastic fibers  26  on bladder  11   c  to allow for expansion and contraction of the bladder as it is inflated to closely fit the inside surface of an HVAC duct. 
     In Operation 
     Referring to FIGS. 1-2,  7 ,  8  and  9 , the duct cleaning apparatus of the invention is utilized to clean relatively small sections of duct work at intervals. By varying the length of the hose  13  and by extending the extensible rod  20 , fairly long sections of duct work may be cleaned utilizing the apparatus  10  of the invention. As shown most clearly in FIG. 7, the duct work is cleaned by positioning the bladder into a duct  30  through an end opening, such as  31  or a removable grating (not shown) or side access port (not shown) of a duct. 
     Depending upon the length of the duct and whether any 45 degree elbows or corners are encountered, bladder  11  may be moved forwardly in the duct  30  through the opening  31  solely by means of the reinforced hose  13 . This may be successfully accomplished by utilizing the metal coil  23  (FIG. 5) in hose  13  positioned so that it extends between the leading portion of hose  13  and the bladder  11  to keep the bladder from doubling back on itself or kinking that would prevent air from being moved into the bladder to expand it. It should be noted that in the embodiment shown in FIG. 7, prior to positioning the bladder  11  in the duct  30  through opening  31 , the bladder  11  and the cleaning cloth  12  surrounding same may be dipped in a liquid cleaning solution which may be kept in a convenient bucket (not shown). If the hose  13  having the coil  23  positioned therein is not sufficiently directionally stable to push the bladder through the duct work  30  to its beginning cleaning position as shown in FIG. 7, the extensible rod  20  may be added to the forward end of the hose  13  at collar  21  to enable that forward end of the bladder to be pushed forwardly a sufficient length to be positioned properly as desired in duct  30 . 
     After the bladder  11  is properly placed in the desired position in the duct work  30 , the valve  15  is opened, pump handle  18  is grasped with one hand, and the reciprocating lever  18   a  is pumped with the user&#39;s other hand to provide air pressure through hose  13  to the bladder  11  to blow up that bladder so as to completely fill the cross section of the duct  30 . This may be accomplished whether that duct is rectangular as shown at  30   a  in FIG. 8 or circular as shown at  30  in FIG.  9 . After sufficient relatively low air pressure, preferably less than one additional atmosphere has been utilized by pump  17  to pump air through hose  13  into bladder  11 , the bladder will fill the cross section of the duct  30  completely to press the wet wash cloth  12  against the inner surface of duct  30 . Once the bladder applies this relatively low pressure to the wash cloth  12 , the hose  13  and the bladder  11  with the wash cloth on the outside thereof are moved or dragged through the duct  30  in a direction toward the opening  31  a sufficient distance to collect a substantial amount of the dirt and grime from the inner wall of the duct  30 . 
     The distance which the bladder  11  and cleaning cloth  12  are moved for each application of the cleaning apparatus  10  to the inside of the duct work is a judgment call of the user depending upon the dirt absorption power of the cleaning cloth  12  and the amount of dirt and debris on the inside surface of the duct  30 . After the bladder  11  and cleaning cloth  12  are dragged or moved the requisite amount along the duct  30 , the air valve  15  is opened to allow the bladder to constrict to provide for easy removal of the apparatus  10  from the duct  30  through the opening  31 . The dirty cloth cover  12 , either off of or remaining on the bladder  11 , is then positioned in the cleaning bucket (not shown) and cleaned, as a mop would be cleaned until the dirt and grime is removed therefrom. Thereafter, the duct work cleaning apparatus  10  of the invention may be repositioned through opening  31  into duct  30  as described previously to either clean an adjacent portion of the duct work  30 , or to apply the bladder  11  and cleaning cloth  12  to the same area previously cleaned to provide a second scrubbing of that same area, if necessary. By inflating the bladder  11  and cleaning cloth  12 , repeatedly, as described, the entire duct work may be cleaned in sections without the need for using complex water pumps, electrically operated air compressors, motor operated turning brushes or the like. 
     As shown most clearly in FIGS. 3,  4  and  5 , traditional cleaning materials such as sponges, brushes and scrub pads may be integrally formed with the outside surface of the bladder  11  to provide outer cleaning surfaces such as sponge  24  as shown in FIG. 6, bristle brushes  25  as shown in FIG.  7  and scrub filaments  26  as shown in FIG.  8 . The construction of the sponge material  24 , the brushes  25  or the scrub filaments  26  may be made such that the expansion of the bladder  11 ,  11   a-c  is accomplished without negatively affecting the usefulness of the scrubbing material positioned on the outside of the bladder. 
     A portable HVAC duct cleaning apparatus has been shown and described that is simpler and more easily portable in construction than heretofore known duct cleaning apparatus for providing superior cleaning capabilities in connection with ridding the interior surfaces of HVAC ducts of dirt, grime, dust, etc. that may adversely affect occupants of a residence, office or factory in which the duct work is positioned. 
     While one embodiment and three modifications of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. It is the intent of the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.