Patent Abstract:
A tube cleaning machine in which cleaning interior tube surfaces occurs by a forward non-cleaning pass of cleaning implement through work tube followed by reverse cleaning pass where implement engages and cleans interior surface. Cleaning implement has first position for forward pass producing minimum engagement of interior fire-tube surface, and a second position for reverse pass of full cleaning engagement with interior fire-tube surface. A distance indicator enables operator to select distance of forward pass of cleaning implement to correspond with tube length.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Non-provisional of, and claims benefit and priority to, U.S. Provisional Patent Application No. 62/122,209 filed on Oct. 14, 2014, the entirety of which is hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Embodiments disclosed herein generally relate to fire-tube boilers and provide solutions to the problem of cleaning the interior surface of fire-tubes with a lighter weight, easier to use machine. 
     The general construction of a fire-tube boiler is a tank of water penetrated by tubes that carry the hot flue gases from the boiler&#39;s combustion chamber. The tank is usually cylindrical for the most part (being the strongest practical shape for a pressurized container) and this cylindrical tank may be either horizontal or vertical. In a fire-tube boiler a large number of fire-tubes are arranged in a boiler drum for generating a large amount of steam (hot water) for its size as compared to flue boilers. Hot combustion gases pass through fire-tubes running through the sealed boiler drum containing water. The heat of the gases is transferred to the water through the walls of the tubes ultimately creating steam. The many small tubes offer far greater heating surface area for the same overall boiler volume. In operation, surface area heat transfer efficiency is diminished by buildup on the fire-tube interior surfaces by products of corrosion, oxidation, soot, and chemical reactions. Fire-tube boiler cleaning machines are available for tube cleaning, however, such machines are very heavy and hard to use in tight spaces or on elevated catwalks, platforms, or scaffolding. Machine weight is determined by the physics of pushing a rigid cleaning brush in a forward stroke down the full length of a tube by means of a steel tape. The steel tape needs to be thick and heavyweight to resist the significant compressive forces encountered in pushing the brush along the tube. Additionally, the machine needs sufficient mass (weight) to withstand the high loads developed on the brush forward stroke. 
     Some embodiments disclosed herein deal with the main problem of conventional fire-tube cleaners, i.e., the weight of the cleaner and component parts. Solutions disclosed herein provide a unique and brilliant way of substituting fire-tube boiler mass for the mass needed by conventional machines to withstand the high loads developed on the brush forward stroke. Embodiments disclosed herein generally, for example, take advantage of boiler mass by providing a machine for tube cleaning on reverse stroke. 
     SUMMARY 
     Fire-tube cleaners according to embodiments described herein utilize lightweight, high strength components to propel a unique easy-push, clean on return stroke brush for tube cleaning. Brush design minimizes friction resistance on the forward stroke of the cleaning cycle, thereby substantially reducing compressive force on the tape pushing the brush and eliminating tendency of tape to collapse, buckle, or bind within a tube. On the return cleaning stroke the tape is in constant tension and can easily handle the forces involved. A preferred embodiment is designed for modern package boilers usually having tubes of maximum length of sixteen (16) feet and of outside diameter of two inches (2″) to two and one half inches (2½″). 
     An operator of the fire-tube cleaner according to some embodiments pre-sets the distance the tape and brush travel according to boiler tube length thereby allowing the operator to concentrate on machine and cleaning cycle. This feature eliminates operator need to concentrate on machine distance monitor to avoid cleaning brush slamming into the far side of the boiler damaging boiler cover, insulation, cleaning brush, etc. 
     The machine may also or alternatively include a distance monitor on both sides of the machine, a centrally located rear-mounted operating switch, and a main drive-train of motor, gearbox, clutch, and final drive located within the machine protecting the operator from moving parts and hot (e.g., one hundred and eighty degrees Fahrenheit (180° F.)) exposed drive motor. The machine allows for quick change of steel tape without the need for machine disassembly. 
     An easy-push, clean on return stroke brush reduces push force through fire-tubes. The brush may be mounted on a restricted movement swivel that allows the brush to fold over passing down the tube, and to setup and remain upright on the return stroke. 
     Specific examples are included in the following description for purposes of clarity, but various details can be changed within the scope of the present invention. 
     OBJECTS OF THE INVENTION 
     An object of the invention is to provide a machine for cleaning tubes. 
     An object of the invention is to provide a machine for cleaning fire-tubes that cleans tubes on brush return stroke thereby to take advantage of boiler mass and reduce cleaning machine mass. 
     Another object of the invention is to provide a lightweight fire-tube cleaner with reduced resistance on brush push stroke and with tube cleaning occurring on the return stroke. 
     Another object of the invention is to provide a fire-tube cleaning machine with lightweight, high strength steel tape to propel brush down the tube. 
     Another object of the invention is to provide fire-tube cleaning machine with preset travel distance for tape selected according to fire-tube length. 
     Another object of the invention is to provide for tube cleaning machine with drive train located within the machine for operator protection. 
     Other and further objects of the invention will become apparent with an understanding of the following detailed description of the invention or upon employment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An understanding of embodiments described herein and many of the attendant advantages thereof may be readily obtained by reference to the following detailed description when considered with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a preferred embodiment of a fire-tube cleaner according to some embodiments; 
         FIG. 2  is a side elevation view of the fire-tube cleaner of  FIG. 1  with first side cover plate removed to illustrate interior components; 
         FIG. 3  is a reverse side perspective view of the fire-tube cleaner of  FIG. 1  and  FIG. 2  with second side cover plate removed to illustrate interior components; 
         FIG. 4A  is fragmentary side view of interior working components of a distance indicator; 
         FIG. 4B  is a perspective view of interior working components of a distance indicator; 
         FIG. 5  is a front elevation view of the distance indicator cover shown in  FIG. 1  and  FIG. 4B ; 
         FIG. 6  is a fragmentary perspective view of a steel tape reel in open position for change of tape; 
         FIG. 7  is a fragmentary perspective view of a steel tape reel in closed position for tape operation in tube cleaning; 
         FIG. 8  is a perspective view of a cleaning brush in a position for feeding into a fire-tube on forward stroke; and 
         FIG. 9  is a perspective view of a cleaning brush in a position for cleaning a fire-tube on return stroke. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 ,  FIG. 2 , and  FIG. 3  of the drawings, a fire-tube cleaning machine  10  includes housing  12  defined by confronting shell members  12   a - b  defining an interior space  14  for placement of cleaner operating components  16  including drive-train  18  and tape reel  20  with drum drive gear  20   a . The housing further includes carry handle  12   c , cover plate  12   d  for access to tape anchor  36  (also shown in  FIG. 6  and  FIG. 7 ), vacuum connection  12   e , and cleaner switch console  12   f . The shell members  12   a - b  are secured to each other by suitable fasteners (not shown) at multiple locations  12   g.    
     A tape  22  and brush and/or brush assembly  24  may be housed in a deployment member in the form of a tape outlet barrel  26  that extends from the housing  12  for insertion into individual fire-tubes  28  so as to position tape  22  and brush assembly  24  at tube entry  28   a . The tape outlet barrel  26  serves as a vacuum conduit for carrying dislodged soot from each tube  28  to a vacuum source (not shown) at vacuum connection  12   e.    
     A distance indicator  30  (described in detail below) may be affixed to a side of housing  12  exterior for pre-setting distance of tape travel according to length of boiler fire-tubes  28 . 
     Layout of interior components according to some embodiments is shown in  FIG. 2  and  FIG. 3  including tape reel  20  with its drive gear  20   a  and tape anchor  36 , and tape reel drive train  18 . 
     Drive train  18  may include, for example, an electric drive motor  18   a  suitably powered with drive shaft  18   b  rotating at one end a cooling fan  18   c , and worm gear box  18   d  at other end. Output pinion  18   f  is positioned between gear box  18   d  and clutch  18   e . Out-put pinion  18   f  is driven by worm gear (not shown; housed inside of the worm gear box  18   d ) to power drive chain or belt  18   g  for turning tape reel  20  by its drive gear  20   a . Power switch  32  has forward, center, and reverse positions for directing rotation of the drive motor  18   a . Tape reel  20  is equipped with a reel stop  20   c  for stopping the reel  20  (e.g., by a stop surface  20   cx  engaging with a stop portion  20   x  of the reel  20 , such as by the reel stop  20   c  rotationally engaging therewith by rotating about a stop pivot  20   cy ) so tape holder or anchor  36  may be stopped/located at housing access panel  12   d  (e.g., for access to allow tape changeover and/or maintenance or adjustment). 
     The distance indicator  30  on one or both sides of the housing  12  sets the distance of payout of tape  22  on brush forward stroke according to the length of fire-tubes  28  in a particular boiler (not shown). Referring to  FIG. 4A , the distance indicator  30  has a first limit switch  30   i  providing an “off” function for the drive motor  18   a  at the end of a length of tape  22  paid out on forward stroke. The operator uses forward/reverse switch  32  on return stroke to pull tape  22  and brush assembly  24  in a cleaning pass through a fire-tube  28 . On return stroke the distance indicator  30  trips a second limit switch  30   j  for providing an “off” function for drive motor  18   a . A distance adjustment control knob  30   m  ( FIG. 1 ) is movable through an adjustment arc defined by an arced slot  30   k  ( FIG. 1  and  FIG. 4B ) in distance indicator  30  for setting payout distance of the tape  22 . 
     Reel drive gear or sprocket  20   a  is fitted with distance indicator drive pinion  20   d  for powering distance indicator  30 . Distance indicator  30  includes outer cover  30   a  secured by retaining bolt  30   b  at socket  30   c  formed in a housing shell member  12   a  or  12   b  with indicator sprocket gear  30   e  ( FIG. 4B ) meshed with teeth of the distance indicator drive pinion  20   d . Inner web  30   f  ( FIG. 4B ) of the indicator sprocket gear  30   e  is provided with a movable forward actuator  30   g  (also shown in  FIG. 2  as engaged with first limit switch  30   i —although with the indicator sprocket gear  30   e  is not shown in  FIG. 2 ) and a stationary or fixed rearward actuator  30   h  cooperating with the first or forward limit switch  30   i  and with the second or rearward limit switch  30   j , which may for example, comprise micro-switches. Forward actuator  30   g  comprises an arcuate bar at a first fixed radius R 1  from sprocket center  30   b - 1  (e.g., coincident with a center axis of the retaining bolt  30   b ), the bar being slidable along the arced slot  30   k  formed in the sprocket web  30   f . The forward actuator fixed radius R 1  is equal to a distance between the sprocket center  30   b - 1  and a contact surface of the first limit switch  30   i . Forward actuator  30   g  and forward limit switch  30   i  cooperate (e.g., as depicted in  FIG. 2 ) to stop tape  22  and brush assembly  24  forward movement into the fire-tube  28 . Rearward actuator  30   h  is affixed to circular rib  30   n  (and/or comprises a raised portion of the circular rib  30   n ) positioned on inner web  30   f  at a second fixed radius R 2  from sprocket center  30   b - 1 . The second fixed radius R 2  is equal to a distance between the sprocket center  30   b - 1  and the rearward limit switch  30   j.    
       FIG. 1  and  FIG. 5  show distance indicator cover  30   a  with slot  30   k  and indicator knob  30   m . The distance travelled forward into a tube by tape  22  and brush assembly  24  in a tube cleaning pass is selected by moving knob  30   m  (and accordingly the attached/cooperative forward actuator  30   g ) along slot  30   k . As shown in  FIG. 5 , indicator cover  30   a  has indicia “I” arranged along its circumference with a portion of indicia “I”, i.e., labels representing numbers/settings seven (7) through sixteen (16), arranged alongside slot  30   k . The indicia “I” correlates to tube length, and by positioning knob  30   m  adjacent a specific value representing a desired/known tube length, the operator thus selects distance cleaning brush assembly  24  travels on forward stroke. The knob  30   m  has a threaded connection (not shown) with forward actuator  30   g  for tightening forward actuator  30   g  in selected position in the slot  30   k . In operation, rearward actuator  30   h  stops tape movement when sprocket  20   a  (e.g., via engagement of the distance indicator drive pinion  20   d ) brings the rearward actuator  30   h  into contact with the rearward limit switch  30   j , as occurs when the tape  22  and brush assembly  24  are withdrawn from a tube  28 . Forward movement of tape  22  and brush assembly  24  in another tube  28  occurs with forward actuation of operating switch  32  by machine operator. Forward movement of tape  22  and brush assembly  24  continues for a pre-selected distance corresponding to the dialed-in position of forward actuator  30   g . Forward movement of tape  22  and brush assembly  24  stops when movable forward actuator  30   g  trips the forward limit switch  30   i . At this point operator uses main switch  32  to reverse tape  22  and brush assembly  24  movement drawing them rearward in a cleaning pass through a tube  28 . 
       FIG. 6  and  FIG. 7  show tape reel or drum  20  for forward unwinding and reverse rewinding of tape  22  for cleaner operation. Tape  22  may comprise a stainless steel band having strength and stiffness capable of pushing tube cleaning brush assembly  24  described herein through the length of a fire-tube  28 , of pulling the brush assembly  24  back through the tube  28  in a cleaning stroke, and having a suitable level of pliability to coil about the tape reel  20 . While typical fire-tube cleaning tape (not shown) must be designed of a sufficient width and thickness to provide approximately two hundred (200) pounds of push force, for example, the tape  22  in accordance with embodiments herein may generally be about half the width and thinner than typical tape, such that the tape  22  of the fire-tube cleaning machine  10  described herein may be designed and configured to maintain structural integrity upon an application of approximately one hundred (100) pounds of push-force. In such a manner, for example, the tape  22  may be approximately one half the weight of typical tapes, significantly reducing the overall wright of the fire-tube cleaning machine  10  as compared to previous cleaning machines for fire-tubes. 
     In some embodiments, on reverse stroke the reel stop  20   c  positions tape notches  22   a  adjacent access panel  12   d . Tape  22  has end notches  22   a  for engagement with a movable anchor  36  fitted to the reel  20 . A spring loaded platform  36   a  positions anchor pins  36   b  in engagement with notches  22   a  for securing tape  22  to reel  20 . Platform  36   a  is lowered to disengage pins  36   b  from notches  22   a  when tape  22  is replaced. Spring  36   c  urges platform  36   a  and pins  36   b  into normal position of anchoring pins  36   b  to tape notches  22   a . Cover plate  12   d  ( FIG. 1  and  FIG. 3 ) provides access to platform  36   a  and tape notches  22   a  so that tape  22  can be changed without dismantling the cleaner housing  12 . Rollers  34  remove binding friction on the tape  22  when outward bound into a tube  28 . 
       FIG. 8  and  FIG. 9  illustrate brush assembly  24  of cleaning brush  24   a  and brush head  24   b . Cleaning brush  24   a  is attached to tape  22  by means of brush head  24   b . Brush head  24   b  comprises an elongate block  24   c  with center recess  24   d  for insertion and securing tape end  22   b  to the block  24   c  using suitable fasteners  24   e . Block end  24   f  has spaced arms  24   g - h  defining between them a socket  24   i  for receiving cleaning brush subassembly of brush  24   a  and brush post  24   j . Brush post  24   j  is nested within socket  24   i  and secured to arms  24   g - h  by pivot pin  24   k  for pivotal movement of brush  24   a  and brush post  24   j  from horizontal to vertical positions of  FIG. 8  and  FIG. 9 , respectively. Brush subassembly has normal position as shown in  FIG. 8 , and sets up to vertical position when tape  22  is in reverse stroke pulling brush  24   a  through a fire tube  28 . The brush  24   a  itself is mounted by securing bolt  24   m  on brush post  24   j  for free-wheeling rotation about brush axis X-X′. In some embodiments, the term “vertical” may be descriptive of (and/or specifically defined as) the brush  24   a  being oriented such that a centerline of the securing bolt  24   m  (not separately labeled) is oriented along the X-X′ axis. According to some embodiments, the term “horizontal” may be descriptive of (and/or specifically defined as) the brush  24   a  being oriented such that the centerline of the securing bolt  24   m  (not separately labeled) is oriented perpendicular to the X-X′ axis. 
     The brush  24   a  includes cleaning strips or blades  24   n  of suitable material extending radially from brush axis X-X′. The brush strips  24   n  may be pitched at an angle to brush axis X-X′ to promote rotation and cleaning action of the brush  24   a  as it travels in reverse stroke through a fire-tube  28 . 
     The underside of brush head  24   b  defines a recess  24   p  to accommodate positioning of the brush  24   a  horizontally ( FIG. 8 ). The tape  22  and brush assembly  24  are in position of  FIG. 8  on forward stroke for pushing brush  24   a  through a fire-tube  28  to initiate cleaning operation. For a reverse stroke or cleaning pass, the tape  22  pulls brush  24   a  back through a fire-tube  28 . In this cleaning pass, the brush  24   a  pivots to vertical ( FIG. 9 ) with brush tips (not separately labeled) engaging interior fire-tube surface (not shown) while rotating and scrubbing soot and other dirt and contaminants (not shown) from the tube  28 . A vacuum source (not shown) secured to machine vacuum connection  12   e  draws scrubbed material (not shown) from fire-tube  28  through machine barrel  26 . 
     In use of the fire-tube cleaning machine  10 , an operator sets distance indicator  30  according to fire-tube length for a particular boiler (not shown). With brush assembly  24  in position of  FIG. 8 , operator advances the brush assembly  24  in a forward stroke by reeling out the tape  22  the set distance. Diametrically opposed edges of brush blades  24   n  slip along interior fire-tube surface with minimum resistance. Here the chief requirement of the machine  10  is for a tape  22  of sufficient strength to push against this minimum resistance. The need for a massive conventional machine to support a forward stroke cleaning pass is eliminated. For cleaning the fire-tube  28 , the tape  22  is pulled through reverse stroke with brush assembly  24  setting up to position of  FIG. 9  with entire complement of blade tips scrubbing tube interior. On the reverse pass, the boiler (not shown) provides mass and cleaning machine  10  provides lightweight, high strength structure for pulling brush  24   a  back through each tube  28 . 
     Various changes may be made to the structure embodying the principles of the embodiments described herein without deviating from the scope of the overall invention. The foregoing embodiments are set forth in an illustrative and not in a limiting sense. The foregoing description has particular reference to cleaning boiler fire-tubes, however, it is understood that the cleaning machine described herein may be used for a wide variety of tube cleaning applications. 
     The present disclosure provides, to one of ordinary skill in the art, an enabling description of several embodiments and/or inventions. Some of these embodiments and/or inventions may not be claimed in the present application, but may nevertheless be claimed in one or more continuing applications that claim the benefit of priority of the present application. Applicants intend to file additional applications to pursue patents for subject matter that has been disclosed and enabled but not claimed in the present application.

Technology Classification (CPC): 5