Patent Publication Number: US-2009229068-A1

Title: Detonative cleaning apparatus mounting system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from and incorporates in its entirety by reference U.S. Provisional Patent Application Ser. No. 61/028,491, filed Feb. 13, 2008, entitled “Detonative Cleaning Apparatus Mounting.” 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The disclosure relates to industrial equipment. More particularly, the disclosure relates to the detonative cleaning of industrial equipment. 
     BACKGROUND OF THE INVENTION 
     Surface fouling is a major problem in industrial equipment. Such equipment includes furnaces (coal, oil, waste, etc.), boilers, gasifiers, reactors, heat exchangers, and the like. Typically, the equipment involves a vessel containing internal heat transfer surfaces that are subjected to fouling by accumulating particulate such as soot, ash, minerals and other products and byproducts of combustion, more integrated buildup such as slag and/or fouling, and the like. Such particulate build-up may progressively interfere with plant operation, reducing efficiency and throughput and potentially causing damage. Cleaning of the equipment is therefore highly desirable and is attended by a number of relevant considerations. Often direct access to the fouled surfaces is difficult. Additionally, to maintain revenue, it is desirable to minimize industrial equipment downtime and related costs associated with cleaning. A variety of technologies have been proposed. Such systems are often identified as “soot blowers” after an exemplary application for the technology. 
     Basic soot blower configuration is the scheme lance soot blower. Additionally, combustion soot blower technologies have been proposed. Recent examples include those of U.S. Pat. Nos. 7,011,047 and 7,442,034 and US Patent Publication Nos. 20050126594 and 20050130084, both now abandoned, the disclosures of which are incorporated by reference in their entireties herein as if set forth at length. 
     SUMMARY OF THE INVENTION 
     Accordingly, one aspect of the disclosure involves an apparatus for cleaning a surface within a vessel. An elongate combustion conduit extends from an upstream end to a downstream end associated with an aperture in the wall of the vessel and positioned to direct a shockwave toward the surface. One or more hangers support the combustion conduit at one or more locations along a length of the combustion conduit. A penetration conduit is positioned between the wall aperture and an associated portion of the combustion conduit. Means couple the combustion conduit to the penetration conduit so as to accommodate one or both of relative longitudinal movement and relative angular movement. 
     In various implementations, the means for coupling may accommodate the relative longitudinal movement via a slip fit and the relative angular movement via flexing. The slip fit may be of an apertured plate held by a bellows or expansion joint. The flexing may be of the bellows or expansion joint. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially schematic side view of a soot blower associated with an industrial furnace. 
         FIG. 2  is a top view of the soot blower of  FIG. 1 . 
         FIG. 3  is an enlarged side view of a discharge/outlet end of the soot blower of  FIG. 1 . 
         FIG. 4  is a transverse sectional view of the soot blower of  FIG. 3 . 
         FIG. 5  is a partial vertical longitudinal sectional view of the soot blower end portion. 
         FIG. 6  is a view of a damper of the soot blower of  FIG. 1 . 
         FIG. 7  is a sectional view of the damper of  FIG. 6 . 
         FIG. 8  is a side view of an alternate soot blower. 
         FIG. 9  is a top view of the soot blower of  FIG. 8 . 
         FIG. 10  is a view of a first pair of thrust reaction plates secured to a flange joint. 
         FIG. 11  is an end view of the plates and joint of  FIG. 10 . 
         FIG. 12  is an X-ray view of one of the plates of  FIG. 10 . 
         FIG. 13  is a view of the plate of  FIG. 12 . 
         FIG. 14  is an end view of the plates and joints carrying devises. 
         FIG. 15  is an end view of plates and joints carrying first alternatively oriented devises. 
         FIG. 16  is an end view of plates and joints carrying second alternatively oriented devises. 
         FIG. 17  is a view of alternate thrust reaction plates secured to a joint. 
         FIG. 18  is an end view of the plates and joint of  FIG. 17 . 
         FIG. 19  is a view of a single thrust reaction plate secured between flanges of a joint. 
         FIG. 20  is an end view of the plate and joint of  FIG. 19 . 
         FIG. 21  is a top view of an alternate embodiment of the sootblower of  FIG. 1 . 
         FIG. 22  is a side view of the sootblower of  FIG. 21 . 
         FIG. 23  is an end view of the thrust reaction plates and joint of  FIG. 22 . 
         FIG. 24  is a perspective view of a thrust reaction plate of  FIG. 23 . 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a vessel (e.g., a boiler)  20  in a building  21 . One or more soot blower apparatus (soot blowers)  22  are positioned to clean surfaces within the vessel interior  78 . The exemplary vessel comprises a wall  24 . The exemplary wall  24  may include a structural and/or insulative outer layer  26  and an inner layer  28 . In high temperature locations along the wall  24 , the inner layer  28  may be a heat transfer layer formed of fluid (e.g., water)-carrying tubes. Exemplary tubes are welded together to form a membrane wall. In lower temperature locations, the inner layer  28  may be a steel plate. For further structural reinforcement against internal or external pressure loads, the wall  24  may include reinforcements commonly known as buckstays  30 . Exemplary buckstays  30  are steel I-beams secured to each other and to the remaining wall structure to form a rigid enclosure. The wall  24  is subject to thermal growth as the vessel temperature increases. The growth may be accommodated by suspending the vessel via the buckstays  30  from a relatively fixed building structure such as a ceiling  32 . As the vessel heats, the wall  24  grows vertically downward. 
     Each soot blower  22  includes an elongate combustion conduit  36  extending from a first (e.g., an upstream/distal/inlet end)  38  away from the vessel wall  24  to a second (e.g., downstream/proximal/outlet) end  40  closely associated with the wall  24 . Optionally, however, the end  40  may be well within the vessel interior  78 . In operation of each soot blower  22 , combustion of a fuel/oxidizer mixture within the conduit  36  is initiated proximate the upstream end  38  (e.g., within an upstreammost 10% of a conduit length) to produce a detonation wave which is expelled from the downstream end  40  as a shock wave along with associated combustion gases for cleaning surfaces within the interior volume of the furnace. Each soot blower  22  may be associated with a fuel/oxidizer source  42 . Such source or one or more components thereof may be shared amongst the various soot blowers. An exemplary source includes a liquified or compressed gaseous fuel cylinder  44  and an oxygen cylinder  46  in respective containment structures  48  and  50 . 
     In one example, there is a single fuel (e.g., propane) and a single oxidizer (e.g., the pure oxygen). In second example, the oxidizer is a first oxidizer such as essentially pure oxygen. A second oxidizer may be in the form of shop air delivered from a central air source  52 . In the second example, air may be stored in an air accumulator  54 . Fuel, expanded from that in the cylinder  46  may be stored in a fuel accumulator  56 . Each exemplary source  42  is coupled to the associated conduit  36  by appropriate plumbing. Similarly, each soot blower  22  includes a spark box  60  coupled to an igniter  61  for initiating combustion of the fuel oxidizer  4  mixture and which, along with the source  42 , is controlled by a control and monitoring system  62 . 
     In exemplary embodiments of the second example, the fuels are hydrocarbons. In particular exemplary embodiments, both fuels are the same, drawn from a single fuel source but mixed with distinct oxidizers: essentially pure oxygen for the predetonator mixture; and air for the main mixture. Exemplary fuels useful in such a situation are propane, MAPP gas, or mixtures thereof. Other fuels are possible, including ethylene and liquid fuels (e.g., diesel, kerosene, and jet aviation fuels). The oxidizers can include mixtures such as airloxygen mixtures of appropriate ratios to achieve desired main and/or predetonator charge chemistries. Further, monopropellant fuels having molecularly combined fuel and oxidizer components may be options. 
       FIG. 1  shows further details of an exemplary soot blower  22 . The exemplary conduit  36  may be formed by a series of doubly flanged conduit sections or segments arrayed from upstream to downstream and a downstream nozzle conduit section or segment  72  having a downstream portion  74  extending through an aperture  76  in the wall and ending in the downstream end or outlet  40  exposed to the vessel interior  78 . The term nozzle is used broadly and does not require the presence of any aerodynamic contraction, expansion, or combination thereof. Exemplary conduit segment material is metallic (e.g., stainless steel). The outlet  40  may be located further within the vessel if appropriate support and cooling are provided. Within the vessel interior  78  are furnace interior tube bundles  80 , the exterior surfaces of which are subject to fouling and which are to be cleaned by the soot blower  22 . 
     A fuel/oxidizer charge may be introduced to the conduit interior in a variety of ways. As noted above, there may be one or more distinct fuel/oxidizer mixtures. Such mixture(s) may be premixed external to the detonation conduit, or may be mixed at or subsequent to introduction to the conduit. For example, there may be distinct introduction of two distinct fuel/oxidizer combinations: a predetonator combination; and a main combination. There may also be a purge gas conduit connected to a purge gas port. An end plate may be bolted to the upstream flange of the upstream segment to seal the upstream end of the combustion conduit and pass through the igniter/initiator  61  (e.g., a spark plug) having an operative end in the conduit interior. 
     In operation, at the beginning of a use cycle, the combustion conduit is initially empty except for the presence of air (or other purge gas or flue gas). The fuel(s) and oxidizer(s) are introduced. 
     With the charge(s) introduced, the spark box is triggered to provide a spark discharge of the initiator igniting charge (or the predetonator charge in a multi-charge example). The predetonator charge (or single charge) may be selected for very fast combustion chemistry, the initial deflagration quickly transitioning to a detonation producing a detonation wave. Once such a detonation wave occurs, it is effective to pass through the rest of the charge (or the main charge which might, otherwise, have sufficiently slow chemistry to not detonate within the conduit of its own accord). The wave passes longitudinally downstream and emerges from the downstream end  40  as a shock wave within the furnace interior, impinging upon the surfaces to be cleaned and thermally and mechanically shocking to typically at least loosen the contamination. The wave will be followed by the expulsion of pressurized combustion products from the detonation conduit, the expelled products emerging as a jet from the downstream end  40  and further completing the cleaning process (e.g., removing the loosened material). After or overlapping such venting of combustion products, a purge gas (e.g., air from the same source providing the main oxidizer and/or nitrogen) is introduced through the purge port to drive the final combustion products out and leave the detonation conduit filled with purge gas ready to repeat the cycle (either immediately or at a subsequent regular interval or at a subsequent irregular interval (which may be manually or automatically determined by the control and monitoring system). Optionally, a baseline flow of the purge gas may be maintained between charge/discharge cycles so as to prevent gas and particulate from the furnace interior from infiltrating upstream and to assist in cooling of the detonation conduit. 
     In various implementations, internal surface enhancements may substantially increase internal surface area beyond that provided by the nominally cylindrical and frustoconical segment interior surfaces. The enhancement may be effective to assist in the deflagration-to-detonation transition or in the maintenance of the detonation wave. 
     The apparatus may be used in a wide variety of applications. By way of example, just within a typical coal-fired furnace, the apparatus may be applied to: the pendants or secondary superheaters, the convective pass (primary superheaters and the economizer bundles); air preheaters; selective catalyst removers (SCR) scrubbers; the baghouse or electrostatic precipitator; economizer hoppers; ash or other heat/accumulations whether on heat transfer surfaces or elsewhere, and the like. Similar possibilities exist within other applications including oil-fired furnaces, black liquor recovery boilers, biomass boilers, waste reclamation burners (trash burners), and the like. 
     To support the conduit  36 , the exemplary soot blower  22  includes one or more hangers  100  and  102 . The exemplary hanger  100  is positioned relatively upstream and the exemplary hanger  102  relatively downstream. The exemplary hanger  100  couples the conduit  36  to relatively fixed building structure, bypassing the vessel  20 . Exemplary relatively fixed building structure is as a transverse horizontal I-beam  104  or the ceiling  32 . The exemplary hanger  100  connects to a support point  106  along the conduit  36  such as a hanger eyelet and to another eyelet  108  along the I-beam  104 . The exemplary hanger  100  is a spring hanger, more particularly constant load spring hanger. Exemplary spring hangers are available from LISEGA, Inc., Newport, Tenn. 
     The exemplary hanger  102  couples the conduit  36  to the vessel  20 . In the exemplary embodiment, the hanger  102  is coupled to an eyelet  110  secured to one of the buckstays  30  above the conduit  36 . The exemplary hanger  102  connects to a collar  112  encircling the conduit in a slip fit (discussed further below). The exemplary hanger  102  is a spring hanger (e.g., a simple spring hanger, not a constant load spring hanger). 
     The soot blower  22  includes means for resisting recoil of the conduit. The exemplary means for resisting recoil may couple the conduit to relatively fixed building structure to transfer recoil forces to the building structure (and not the wall  24 ).  FIGS. 1 and 2  show means as including a pair of struts  120  (e.g., respectively to the left and right of the conduit  36 ) coupling the conduit to vertical posts  122 . The exemplary struts  120  include an elongate shaft  124  having upstream and downstream ends. At the respective upstream and downstream ends, joints  126  and  128  are provided respectively engaging mating coupling elements  130  and  132  on the conduit  36  and posts, respectively. The exemplary joints  126  and  128  are rods each having a threaded first end mated to end caps of the shaft and having an eyelet second end carrying an apertured ball. The exemplary couplings  130  and  132  are mating devises carrying pins extending through the associated balls. As is discussed further below, the exemplary upstream couplings  130  are mounted to one or more plates  140 ,  142 . Exemplary plates  140  and  142  are respectively mounted to the right and left sides of the conduit  36 . Exemplary plates  140  and  142  are mounted to a downstream face of an upstream flange of one of the sections of the conduit  36 . The coupling elements  130  are, in turn, mounted to the downstream faces of the plates  140  and  142 . 
     Upon firing of the conduit, recoil forces tend to drive the conduit away from the vessel  20 . Slip fit between the collar  112  and the conduit may allow a certain amount of movement. However, the movement is resisted by tensile force transmitted through the struts  120 . As is discussed further below, the struts may include resilient dampers to smoothly absorb the recoil forces and limit peak force loads transferred to the building. An exemplary recoil is limited/constrained to a value of less than about 10 cm (e.g. a value in the range of 1-6 cm, more narrowly 2.5-5 cm). 
     The thermally-induced vertical movement of the vessel  20  may tend to cause associated local vertical movement of the conduit. Even if this can be partially matched by compliance in the hanger  100 , it may be impractical to entirely so address. The result is that the conduit will tend to rotate to a slightly outlet-down orientation. A rigid mounting of the conduit to the vessel would potentially interfere with proper conduit operation across the anticipated range of vessel vertical displacement. Also, there may be relative horizontal displacement. Accordingly, referring to  FIG. 3 , the exemplary apparatus includes means for coupling the conduit to the vessel so as to accommodate relative longitudinal movement (e.g., the recoil) and relative angular movement (e.g., associated with vertical thermal expansion of the vessel or other vertical or horizontal relative movements). The exemplary means includes a penetration conduit  150  which may be rigidly mounted to the wall  24 . For example, the penetration conduit  150  may be in a friction fit or an interference fit with the outer layer  26  or may be secured thereto via brackets or other mounting elements. The exemplary penetration conduit  150  includes an upstream mounting flange  152  outside the vessel. A tubular portion  154  extends from the mounting flange  152  through the wall  24  to an exemplary downstream/outlet end  156  (e.g., a rim). A downstream end portion  155  of the nozzle at the outlet  40  may protrude beyond the rim  156 . 
     Referring to  FIG. 5 , an annular space  160  between the interior surface  162  of the tubular portion  154  and the exterior surface  164  of the conduit downstream portion  74  may have sufficient radial span DR to accommodate relative angular movement of the combustion conduit  36  relative to the penetration conduit  150  and wall  24 . The relative angular movement may include movement characterized by rotation about a horizontal transverse axis (e.g., associated with a pure vertical movement of the vessel relative to one or more upstream support locations of the conduit). The relative angular movement may include movement characterized by rotation about a vertical transverse axis (e.g., associated with a pure horizontal movement of the vessel relative to one or more upstream support locations of the conduit). In addition to these respective pitch and yaw movements, there, potentially may be a roll movement about a longitudinal axis. The span DR may also be effective to accommodate transverse translation movements of up to DR. An exemplary range of angular movement is up to 5° in any direction (for a total range of 10°) from a neutral coaxial condition (e.g., to 0.5-5° in any direction or, more narrowly, 1-4°). 
     The space  160  may be sufficiently sealed to limit exfiltration (outward flow of gases from the vessel interior if a positive pressure system) and/or infiltration (inward flow of air in the case of a negative pressure system). To do this, a closure plate  170  is positioned outside the vessel to provide a higher degree of relative sealing between the penetration conduit and combustion conduit than would be associated with the radial gap of span DR. Referring to  FIGS. 4 and 5 , in the exemplary implementation, the plate  170  has a central aperture  172  which closely accommodates the exterior surface  174  of the conduit downstream portion  74 . An exemplary accommodation is a close radial sliding fit (much closer than DR). However, for a positive pressure system, in particular, the gap may be closed (e.g., by a sealing/structural weld). The exemplary plate  170  is formed in two 180° segments permitting easy assembly over the combustion conduit. The close accommodation of the plate  170  to the combustion conduit requires that relative angular movement between the plate  170  and the flange  152  be accommodated. As seen in  FIG. 5 , this relative movement may be accommodated by a flexible member  180 . An exemplary flexible member  180  is formed as an expansion joint. 
     An exemplary expansion joint is a single or multiple arch elastomeric expansion joint. The illustrated expansion joint is a single arch, doubly flanged expansion joint such as is available from The Mercer Rubber Company of Hauppauge, N.Y., US. The exemplary expansion joint  180  has a flexible arch  182  between a first flange  184  and a second flange  186 . The first flange  184  is bolted to the plate  170 . The second flange  186  is bolted to the flange  152 . The arch may flex to accommodate the relative angular movement. In implementations including those with a fixed non-sliding fit between the plate  170  and the combustion conduit  36 , the arch  182  may also accommodate relative longitudinal displacement. Metallic expansion joints may, however, be used (e.g., where advantageous due to high temperature exposure). 
     For insulation and further sealing, insulation material  190  is positioned within the annular space  160 . Exemplary insulation material comprises fibrous material such as a batt or mat of mineral wool and/or glass fiber which also provides a degree of thermal insulation. The material may be longitudinally captured between the plate  170  and an annular clamp  192  (e.g., a stainless steel band clamp clamping an end portion of the insulation batt/mat to the conduit downstream portion  74 ). With sliding fit between the plate  170  and the conduit  36 , relative longitudinal recoil movement of the combustion conduit  36  relative to the wall will be associated with telescoping movement of the downstream portion  74  relative to the penetration conduit  150 . The initial recoil may longitudinally compress the insulation  190 . A return may re-expand the insulation. 
     For damping recoil and providing a return force,  FIGS. 6 and 7  show damper units  200  which may serve as the joints  126  and/or  128 . Each damper unit has a threaded first end portion  202  and a ball-carrying second end portion  204  (i.e., for forming a ball joint). In the exemplary damper unit  200  one of the end portions forms a piston whereas the other forms a cylinder. The exemplary first end portion  202  is formed on a first shaft having an opposite end secured (e.g., threaded) into a piston head  206 . The exemplary second end portion  204  is along a second shaft whose opposite end is secured to a cylinder  210 . Within the cylinder  210 , at opposite ends of the head  206  are resilient (e.g., rubber or elastomer) disks  212  and  214 . In the exemplary configuration, extension of the damper resiliently compresses the disk  212  whereas compression resiliently compresses the disk  214 . The disks  212  and  214  may be preloaded (i.e., both are under compression when there is no net compressive or tensile force across the damper unit  200 ). With the exemplary damper unit  200 , recoil of the conduit further compresses the disk  214 , absorbing the recoil energy and, then, at least partially relaxing to return the combustion conduit to its initial position. 
     Alternative dampers may be hydraulic snubbers as are available from Piping Technology&amp;Products, Inc. of Houston, Tex. Other devices are available from Taylor Devices Inc. of North Tonawanda, N.Y. as are used in aircraft landing gear shock absorbers. These may be particularly relevant in systems absorbing recoil via compression rather than tension. 
     Referring back to  FIGS. 1 and 2 , the struts  120  have sufficient length to accommodate vertical movement by pivoting at axes of the coupling elements  132  while not substantially affecting the longitudinal position of the conduit  36  relative to the wall  24 .  FIGS. 8 and 9 , however, show an alternative configuration wherein a sliding thrust joint  250  is provided. The joint  250  can vertically slide along fixed building structures such as a vertical I-beams (posts)  252  and  254  to accommodate vertical movement. Recoil thrust loads are transferred through the joint  250  to the structure  252  and  254 . 
       FIG. 9  shows respective posts  252  and  254  on opposite sides of the conduit  36 . The exemplary joint  250  includes pieces of low friction material  256  and  258  respectively sliding along the downstream faces of the downstream flanges of the posts  252  and  254 . Exemplary low friction material is polytetrafluoroethylene (PTFE) or an ultra high molecular weight (UHMW) plastic material. The low friction material is sandwiched between the associated post flange and an associated robust thrust plate  260  and  262 . Exemplary thrust plates may be similarly formed to the plates  140  and  142  of the first embodiment. Exemplary thrust plates are integrated with a flanged pipe joint  266  between two segments of the conduit  36 . Retainer brackets  270  and  272  may capture outboard edges of the respective post flanges to help guide vertical movement. 
       FIGS. 10 and 11  have separate plates  260  and  262  attached to the back face of the downstream flange  280  of one of the conduit segments (mated to the upstream flange  282  of the next segment).  FIGS. 12 and 13  show an individual one of the plates  260 ,  262  as including two through-holes  283  for bolting with the flanges along the bolt circle of the flanges and two additional holes  284  for mounting the coupling elements  130  or the low friction material  256 ,  258  (not shown).  FIGS. 14-16  show alternate mounting configurations for the coupling elements  130  or the low friction material  256 ,  258 . 
       FIGS. 17 and 18  show an alternate plate configuration wherein plates  300  and  302  replace plates  260  and  262 . The plates  300  and  302  are welded to the OD of the flange  280 . 
       FIGS. 19 and 20  show a single plate  310  having lateral portions  312  and  314  which respectively replace the plates  260  and  262 . The plate  310  is shown sandwiched between the flanges  280  and  282 , having a central aperture  316  and a bolt hole circle  320  corresponding to those of the flanges  280  and  282  and receiving the bolts securing the flanges  280  and  282 . Each of the three exemplary configurations may have different advantages. The welded construction of  FIGS. 17 and 18  allows easy retrofitting without need to remove any bolts from the flanges  280  and  282 . However, the welds are directly loaded by the recoil force. Also, the loadpath of the recoil force is spaced outboard of the flange outer diameter (OD). This relatively large radial spacing may cause undesirably high bending loading on the flange  280 . The  FIGS. 10 and 11  plates may require only partial unbolting and without need to separate the flanges  280  and  282 . The force path is brought radially inward and may act more directly against the faces of the flanges, thereby decreasing chance of damage to the flanges. The  FIGS. 19 and 20  embodiment may have a radially outboard force transmission but more evenly circumferentially distributes this force to the associated moments. However, in a retrofit application, it requires full joint disassembly. It may also require use of an additional gasket and replacement of relatively short bolts with relatively longer bolts. 
     Referring to  FIGS. 21 and 22 , an alternative embodiment of the damping unit  400  is shown. The unit  400  comprises a plurality of cylindrical elastomer bumpers  491 , such as model number TCB-2 supplied by EFDYN. As seen in  FIGS. 21 and 22 , four bumpers  491  are arranged along a rod  493  which is threaded into a standard load strut  420 . Referring to  FIGS. 23 and 24 , the thrust plates  460  and  462  attach to the rear flange  480  of the combustor conduit  436 . The thrust plates  460  and  462  are similar to the thrust plate discussed in connection with the previous embodiments with an aperture  497  provided for the rod  493  instead of connecting elements  130  or low friction material  256 ,  258 . Referring back to  FIGS. 21 and 22 , each thrust plate  460  and  462  is clamped between two of the elastomer bumpers  491 . A small preload is applied to the bumpers  491  by nut and washer assemblies  494  on each side. Each nut and washer assembly  494  includes two nuts  495  having a split ring style lock washer  496  between them. Tightening the two nuts  495  together locks them in place on the threaded rod  493 . 
     The elastomer bumpers  491  arranged in this fashion act as a spring/damper system in both recoil (from the initial detonation thrust load) and in rebound as the kinetic energy absorbed by the bumpers  491  is released and pushes the combustor conduit  436  back toward the vessel wall  424 . 
     The elastomer bumpers  491  having a wide range of load ratings may be selected for different combustor conduit diameters and thrust loads. Accordingly, this damping unit is easily scalable up and down for various combustor diameters and thrust loads. 
     The damping unit  400  has been demonstrated in the field and is capable of installation as a retrofit to an existing sootblower or as part of a new installation. Testing in the field for a twelve inch (12″) diameter combustor conduit showed about a half inch (0.5″) total recoil from the initial blast, with a sinusoidal decaying motion of the combustor that was completely damped to rest in four to five cycles of motion. The field testing showed nearly a reduction factor of four (4) in load transmitted through the struts to the vessel building structure when the elastomer bumpers  491  were utilized. This reduction is very significant as it greatly reduces the amount of local reinforcement customers must add to their vessel building structure for mounting of combustors. 
     One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the invention may be adapted for use with a variety of industrial equipment and with variety of soot blower technologies. Aspects of the existing equipment and technologies may influence aspects of any particular implementation. Accordingly, other embodiments are within the scope of the following claims.