Fire-tube boiler cleaner

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.

Description

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'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 12a-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 20a. The housing further includes carry handle 12c, cover plate 12d for access to tape anchor 36 (also shown in FIG. 6 and FIG. 7), vacuum connection 12e, and cleaner switch console 12f. The shell members 12a-b are secured to each other by suitable fasteners (not shown) at multiple locations 12g.

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 28a. 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 12e.

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 20a and tape anchor 36, and tape reel drive train 18.

Drive train 18 may include, for example, an electric drive motor 18a suitably powered with drive shaft 18b rotating at one end a cooling fan 18c, and worm gear box 18d at other end. Output pinion 18f is positioned between gear box 18d and clutch 18e. Out-put pinion 18f is driven by worm gear (not shown; housed inside of the worm gear box 18d) to power drive chain or belt 18g for turning tape reel 20 by its drive gear 20a. Power switch 32 has forward, center, and reverse positions for directing rotation of the drive motor 18a. Tape reel 20 is equipped with a reel stop 20c for stopping the reel 20 (e.g., by a stop surface 20cx engaging with a stop portion 20x of the reel 20, such as by the reel stop 20c rotationally engaging therewith by rotating about a stop pivot 20cy) so tape holder or anchor 36 may be stopped/located at housing access panel 12d (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 30i providing an “off” function for the drive motor 18a 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 30j for providing an “off” function for drive motor 18a. A distance adjustment control knob 30m (FIG. 1) is movable through an adjustment arc defined by an arced slot 30k (FIG. 1 and FIG. 4B) in distance indicator 30 for setting payout distance of the tape 22.

Reel drive gear or sprocket 20a is fitted with distance indicator drive pinion 20d for powering distance indicator 30. Distance indicator 30 includes outer cover 30a secured by retaining bolt 30b at socket 30c formed in a housing shell member 12a or 12b with indicator sprocket gear 30e (FIG. 4B) meshed with teeth of the distance indicator drive pinion 20d. Inner web 30f (FIG. 4B) of the indicator sprocket gear 30e is provided with a movable forward actuator 30g (also shown in FIG. 2 as engaged with first limit switch 30i—although with the indicator sprocket gear 30e is not shown in FIG. 2) and a stationary or fixed rearward actuator 30h cooperating with the first or forward limit switch 30i and with the second or rearward limit switch 30j, which may for example, comprise micro-switches. Forward actuator 30g comprises an arcuate bar at a first fixed radius R1 from sprocket center 30b-1 (e.g., coincident with a center axis of the retaining bolt 30b), the bar being slidable along the arced slot 30k formed in the sprocket web 30f. The forward actuator fixed radius R1 is equal to a distance between the sprocket center 30b-1 and a contact surface of the first limit switch 30i. Forward actuator 30g and forward limit switch 30i 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 30h is affixed to circular rib 30n (and/or comprises a raised portion of the circular rib 30n) positioned on inner web 30f at a second fixed radius R2 from sprocket center 30b-1. The second fixed radius R2 is equal to a distance between the sprocket center 30b-1 and the rearward limit switch 30j.

FIG. 1 and FIG. 5 show distance indicator cover 30a with slot 30k and indicator knob 30m. The distance travelled forward into a tube by tape 22 and brush assembly 24 in a tube cleaning pass is selected by moving knob 30m (and accordingly the attached/cooperative forward actuator 30g) along slot 30k. As shown in FIG. 5, indicator cover 30a 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 30k. The indicia “I” correlates to tube length, and by positioning knob 30m 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 30m has a threaded connection (not shown) with forward actuator 30g for tightening forward actuator 30g in selected position in the slot 30k. In operation, rearward actuator 30h stops tape movement when sprocket 20a (e.g., via engagement of the distance indicator drive pinion 20d) brings the rearward actuator 30h into contact with the rearward limit switch 30j, 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 30g. Forward movement of tape 22 and brush assembly 24 stops when movable forward actuator 30g trips the forward limit switch 30i. 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 20c positions tape notches 22a adjacent access panel 12d. Tape 22 has end notches 22a for engagement with a movable anchor 36 fitted to the reel 20. A spring loaded platform 36a positions anchor pins 36b in engagement with notches 22a for securing tape 22 to reel 20. Platform 36a is lowered to disengage pins 36b from notches 22a when tape 22 is replaced. Spring 36c urges platform 36a and pins 36b into normal position of anchoring pins 36b to tape notches 22a. Cover plate 12d (FIG. 1 and FIG. 3) provides access to platform 36a and tape notches 22a 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 24a and brush head 24b. Cleaning brush 24a is attached to tape 22 by means of brush head 24b. Brush head 24b comprises an elongate block 24c with center recess 24d for insertion and securing tape end 22b to the block 24c using suitable fasteners 24e. Block end 24f has spaced arms 24g-h defining between them a socket 24i for receiving cleaning brush subassembly of brush 24a and brush post 24j. Brush post 24j is nested within socket 24i and secured to arms 24g-h by pivot pin 24k for pivotal movement of brush 24a and brush post 24j 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 24a through a fire tube 28. The brush 24a itself is mounted by securing bolt 24m on brush post 24j 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 24a being oriented such that a centerline of the securing bolt 24m (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 24a being oriented such that the centerline of the securing bolt 24m (not separately labeled) is oriented perpendicular to the X-X′ axis.

The brush 24a includes cleaning strips or blades 24n of suitable material extending radially from brush axis X-X′. The brush strips 24n may be pitched at an angle to brush axis X-X′ to promote rotation and cleaning action of the brush 24a as it travels in reverse stroke through a fire-tube 28.

The underside of brush head 24b defines a recess 24p to accommodate positioning of the brush 24a horizontally (FIG. 8). The tape 22 and brush assembly 24 are in position of FIG. 8 on forward stroke for pushing brush 24a through a fire-tube 28 to initiate cleaning operation. For a reverse stroke or cleaning pass, the tape 22 pulls brush 24a back through a fire-tube 28. In this cleaning pass, the brush 24a 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 12e 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 24n 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 24a 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.

Claims

1. A tube cleaner comprising, a machine housing defining space for mounting a tape reel, a tape attached to the tape reel for forward and reverse movement of the tape through a length of a tube, a drive train for imparting forward and reverse movement to the tape reel and the tape, the machine housing having a tape outlet member for directing the tape into the tube, means for removably securing a first end of the tape to the tape reel, a brush assembly attached to a second and opposite end of the tape, the brush assembly comprising a brush head, means for securing the second end of the tape to the brush head, the brush head comprising a brush subassembly comprising a brush and a brush post secured to the brush head, the brush subassembly having a first normal position wherein the brush encounters minimum resistance between the brush and an interior surface of the tube on forward movement of the tape and the brush through the tube, the brush subassembly having a second cleaning position wherein the brush fully engages and cleans the interior surface of the tube on reverse movement of the tape and the brush through the tube, and the brush head comprising an end socket, the brush post nested in the end socket and secured in the end socket by a pivot pin so the brush is free to move from the first normal position to the second cleaning position.

2. A tube cleaner comprising, a machine housing defining space for mounting a tape reel, a tape attached to the tape reel for forward and reverse movement of the tape through a length of a tube, a drive train for imparting forward and reverse movement to the tape reel and the tape, the machine housing having a tape outlet member for directing the tape into the tube, anchor pins for removably securing a first end of the tape to the tape reel, an access panel in the machine housing for moving the anchor pins for disconnecting and reconnecting the tape to the tape reel, a brush assembly attached to a second and opposite end of the tape, the brush assembly comprising a brush head, means for securing the second end of the tape to the brush head, the brush head comprising a brush subassembly comprising a brush and a brush post secured to the brush head, the brush subassembly having a first normal position wherein the brush encounters minimum resistance between the brush and an interior surface of the tube on forward movement of the tape and the brush through the tube, the brush subassembly having a second cleaning position wherein the brush fully engages and cleans the interior surface of the tube on reverse movement of the tape and the brush through the tube, and the brush head comprising an end socket, the brush post nested in the end socket and secured in the end socket by a pivot pin so the brush is free to move from the first normal position to the second cleaning position.

3. A tube cleaner comprising, a machine housing defining space for mounting a tape reel, a tape attached to the tape reel for forward and reverse movement of the tape through a length of a tube, a drive train including a drive motor for imparting forward and reverse movement to the tape reel and the tape, the machine housing having a tape outlet member for directing the tape into the tube, means for removably securing a first end of the tape to the tape reel, a brush assembly attached to a second and opposite end of the tape, the brush assembly having a first normal position wherein a brush of the brush assembly encounters minimum resistance between the brush and an interior surface of the tube on forward movement of the tape and the brush assembly through the tube, the brush assembly having a second cleaning position wherein the brush fully engages and cleans the interior surface of the tube on reverse movement of the tape and the brush through the tube, a distance indicator for matching the distance of forward movement of the brush assembly with length of the tube, the distance indicator powered by the drive train, the distance indicator having an adjustable actuator cooperating with a first switch means for stopping the drive train when the brush assembly forward movement matches the length of the tube, the distance indicator having a fixed actuator cooperating with a second switch means for stopping the drive train when the brush assembly reverse movement withdraws the brush assembly from the tube.

4. A tube cleaner as defined in claim 3 further comprising, a main switch enabling an operator to determine forward, reverse, and stop positions of the drive motor.