Patent Publication Number: US-2005126594-A1

Title: Soot blower access apparatus

Description:
BACKGROUND OF THE INVENTION  
      (1) Field of the Invention  
      The invention relates to industrial equipment. More particularly, the invention relates to the cleaning of industrial equipment.  
      (2) Description of the Related Art  
      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. By way of example, various technologies have been proposed in U.S. Pat. Nos. 5,494,004 and 6,438,191 and U.S. patent application Publication 2002/0112638. Additional technology is disclosed in Huque, Z. Experimental Investigation of Slag Removal Using Pulse Detonation Wave Technique, DOE/HBCU/OMI Annual Symposium, Miami, Fla., Mar. 16-18, 1999. Particular blast wave techniques are described by Hanjalić and Smajević in their publications: Hanjalić, K. and Smajević, I., Further Experience Using Detonation Waves for Cleaning Boiler Heating Surfaces, International Journal of Energy Research Vol. 17, 583-595 (1993) and Hanjalić, K. and Smajević, I., Detonation-Wave Technique for On-load Deposit Removal from Surfaces Exposed to Fouling: Parts I and II, Journal of Engineering for Gas Turbines and Power, Transactions of the ASME, Vol. 1, 116 223-236, January 1994. Such systems are also discussed in Yugoslav patent publications P 1756/88 and P 1728/88. Such systems are often identified as “soot blowers” after an exemplary application for the technology.  
      Nevertheless, there remain opportunities for further improvement in the field.  
     SUMMARY OF THE INVENTION  
      One aspect of the invention is directed to an apparatus for providing detonative cleaning communication through a vessel wall. A first conduit extends from the vessel wall. A first valve has an open condition permitting communication through the first conduit and a closed condition. A second conduit has an insertion portion dimensioned to be received within a receiving portion of the first conduit. A second valve has an open condition permitting communication through the second conduit and a closed condition.  
      In various implementations, one valve may be a sliding gate valve and the other valve may be a sliding gate valve or a hinged gate valve. One of the valves may be manually-actuated or machine-actuated and the other may manually-actuated or machine-actuated. There may be means for sealing the first conduit relative to the second conduit over a first range of insertion of the second conduit within the first conduit. The second conduit may have an interior surface off-axis to an exterior surface.  
      Another aspect of the invention involves an apparatus for providing detonative cleaning communication through a vessel wall. A conduit defines a flow path through the vessel wall. A valve along the flow path has an open condition and a closed condition.  
      In various implementations, a source of fuel and oxidizer may be coupled to the conduit. Means may ignite charges of the fuel and the oxidizer. The valve may be secured relative to the wall. The valve may be along a downstream half of the flow path. The valve may be a first valve at an upstream end of an access conduit. The apparatus may include a second valve along the conduit upstream of the first valve and upstream of an insertion portion of the conduit within the access conduit. The valve may be a first valve between a main portion of the conduit and a downstream insertion portion of the conduit. The apparatus may include a second valve at an upstream end of an access conduit receiving the insertion portion.  
      Another aspect of the invention involves a method for cleaning a surface within a vessel. The vessel has a wall and an access conduit initially sealed by a first valve. An insertion portion of a combustion conduit is inserted into the access conduit. The combustion conduit has a second valve. A seal is formed between the access conduit and the combustion conduit. The first valve is opened. The second valve is opened. Combustion gases are passed through the combustion conduit into the vessel. The insertion portion is withdrawn from the access conduit.  
      In various implementations, the first valve may be opened during an intermediate stage of the insertion. A seal may be formed between the combustion conduit and the access conduit. The seal may be formed before the opening of the first valve. The opening one valve may comprise a pivotal movement of a gate of that valve. The opening of the other valve may be manual.  
      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 view of an industrial furnace associated with several soot blowers positioned to clean a level of the furnace.  
       FIG. 2  is a side view of one of the blowers of  FIG. 1 .  
       FIG. 3  is a partially cut-away side view of an upstream end of the blower of  FIG. 2 .  
       FIG. 4  is a longitudinal sectional view of a main combustor segment of the soot blower of  FIG. 2 .  
       FIG. 5  is an end view of the segment of  FIG. 4 .  
       FIG. 6  is a partial sectional view of a combustion conduit outlet end and furnace access apparatus combination in an initial stage of interaction.  
       FIG. 7  is a view of the combination of  FIG. 6  in a final stage of interaction.  
       FIG. 8  is a partial sectional view of a second combustion conduit outlet end and furnace access apparatus combination in an initial stage of interaction.  
       FIG. 9  is a view of the combination of  FIG. 8  in a final stage of interaction.  
       FIG. 10  is a partial sectional view of a third combustion conduit outlet end and furnace access apparatus combination in an initial stage of interaction.  
       FIG. 11  is a view of the combination of  FIG. 10  in a final stage of interaction.  
       FIG. 12  is a partial sectional view of a fourth combustion conduit outlet end and furnace access apparatus combination in a final stage of interaction.  
       FIG. 13  is a view of a fifth access apparatus.  
       FIG. 14  is an exploded, partially sectional, side view of a fifth combustion conduit outlet end.  
       FIG. 15  is a view of the access apparatus of  FIG. 13  and conduit outlet end of  FIG. 14  in a first intermediate stage of assembly.  
       FIG. 16  is a view of the access apparatus and outlet end of  FIG. 15  in a second intermediate stage of assembly.  
       FIG. 17  is a view of the access apparatus and combustion conduit outlet end of  FIG. 15  in a final stage of assembly.  
       FIG. 18  is a partial sectional view of a sixth combustion conduit outlet end and furnace access apparatus combination in a final stage of interaction. 
    
    
      Like reference numbers and designations in the various drawings indicate like elements.  
     DETAILED DESCRIPTION  
       FIG. 1  shows a furnace  20  having an exemplary three associated soot blowers  22 . In the illustrated embodiment, the furnace vessel is formed as a right parallelepiped and the soot blowers are all associated with a single common wall  24  of the vessel and are positioned at like height along the wall. Other configurations are possible (e.g., a single soot blower, one or more soot blowers on each of multiple levels, and the like).  
      Each soot blower  22  includes an elongate combustion conduit  26  extending from an upstream distal end  28  away from the furnace wall  24  to a downstream proximal end  30  closely associated with the wall  24 . Optionally, however, the end  30  may be well within the furnace. In operation of each soot blower, combustion of a fuel/oxidizer mixture within the conduit  26  is initiated proximate the upstream end (e.g., within an upstreammost 10% of a conduit length) to produce a detonation wave which is expelled from the downstream end as a shock wave along with associated combustion gases for cleaning surfaces within the interior volume of the furnace. Each soot blower may be associated with a fuel/oxidizer source  32 . 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  34  and an oxygen cylinder  36  in respective containment structures  38  and  40 . In the exemplary embodiment, 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  42 . In the exemplary embodiment, air is stored in an air accumulator  44 . Fuel, expanded from that in the cylinder  34  is generally stored in a fuel accumulator  46 . Each exemplary source  32  is coupled to the associated conduit  26  by appropriate plumbing below. Similarly, each soot blower includes a spark box  50  for initiating combustion of the fuel oxidizer mixture and which, along with the source  32 , is controlled by a control and monitoring system (not shown).  FIG. 1  further shows the wall  24  as including a number of ports for inspection and/or measurement. Exemplary ports include an optical monitoring port  54  and a temperature monitoring port  56  associated with each soot blower  22  for respectively receiving an infrared and/or visible light video camera and thermocouple probe for viewing the surfaces to be cleaned and monitoring internal temperatures. Other probes/monitoring/sampling may be utilized, including pressure monitoring, composition sampling, and the like.  
       FIG. 2  shows further details of an exemplary soot blower  22 . The exemplary detonation conduit  26  is formed with a main body portion formed by a series of doubly flanged conduit sections or segments  60  arrayed from upstream to downstream and a downstream nozzle conduit section or segment  62  having a downstream portion  64  extending through an aperture  66  in the wall and ending in the downstream end or outlet  30  exposed to the furnace interior  68 . 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  30  may be located further within the furnace if appropriate support and cooling are provided.  FIG. 2  further shows furnace interior tube bundles  70 , the exterior surfaces of which are subject to fouling. In the exemplary embodiment, each of the conduit segments  60  is supported on an associated trolley  72 , the wheels of which engage a track system  74  along the facility floor  76 . The exemplary track system includes a pair of parallel rails engaging concave peripheral surfaces of the trolley wheels. The exemplary segments  60  are of similar length L 1  and are bolted end-to-end by associated arrays of bolts in the bolt holes of their respective flanges. Similarly, the downstream flange of the downstreammost of the segments  60  is bolted to the upstream flange of the nozzle  62 . In the exemplary embodiment, a reaction strap  80  (e.g., cotton or thermally/structurally robust synthetic) in series with one or more metal coil reaction springs  82  is coupled to this last mated flange pair and connects the combustion conduit to an environmental structure such as the furnace wall for resiliently absorbing reaction forces associated with discharging of the soot blower and ensuring correct placement of the combustion conduit for subsequent firings. Optionally, additional damping (not shown) may be provided. The reaction strap/spring combination may be formed as a single length or a loop. In the exemplary embodiment, this combined downstream section has an overall length L 2 .  
      Extending downstream from the upstream end  28  is a predetonator conduit section/segment  84  which also may be doubly flanged and has a length L 3 . The predetonator conduit segment  84  has a characteristic internal cross-sectional area (transverse to an axis/centerline  500  of the conduit) which is smaller than a characteristic internal cross-sectional area (e.g., mean, median, mode, or the like) of the downstream portion ( 60 ,  62 ) of the combustion conduit. In an exemplary embodiment involving circular sectioned conduit segments, the predetonator cross-sectional area is a characterized by a diameter of between 8 cm and 12 cm whereas the downstream portion is characterized by a diameter of between 20 cm and 40 cm. Accordingly, exemplary cross-sectional area ratios of the downstream portion to the predetonator segment are between 1:1 and 10:1, more narrowly, 2:1 and 10:1. An overall length L between ends  28  and  30  may be 1-15 m, more narrowly, 5-15 m. In the exemplary embodiment, a transition conduit segment  86  extends between the predetonator segment  84  and the upstreammost segment  60 . The segment  86  has upstream and downstream flanges sized to mate with the respective flanges of the segments  84  and  60  has an interior surface which provides a smooth transition between the internal cross-sections thereof. The exemplary segment  86  has a length L 4 . An exemplary half angle of divergence of the interior surface of segment  86  is ≦12°, more narrowly 5-10°.  
      A fuel/oxidizer charge may be introduced to the detonation conduit interior in a variety of ways. 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.  FIG. 3  shows the segments  84  and  86  configured for distinct introduction of two distinct fuel/oxidizer combinations: a predetonator combination; and a main combination. In the exemplary embodiment, in an upstream portion of the segment  84 , a pair of predetonator fuel injection conduits  90  are coupled to ports  92  in the segment wall which define fuel injection ports. Similarly, a pair of predetonator oxidizer conduits  94  are coupled to oxidizer inlet ports  96 . In the exemplary embodiment, these ports are in the upstream half of the length of the segment  84 . In the exemplary embodiment, each of the fuel injection ports  92  is paired with an associated one of the oxidizer ports  96  at even axial position and at an angle (exemplary 90° shown, although other angles including 180° are possible) to provide opposed jet mixing of fuel and oxidizer. Discussed further below, a purge gas conduit  98  is similarly connected to a purge gas port  100  yet further upstream. An end plate  102  bolted to the upstream flange of the segment  84  seals the upstream end of the combustion conduit and passes through an igniter/initiator  106  (e.g., a spark plug) having an operative end  108  in the interior of the segment  84 .  
      In the exemplary embodiment, the main fuel and oxidizer are introduced to the segment  86 . In the illustrated embodiment, main fuel is carried by a number of main fuel conduits  112  and main oxidizer is carried by a number of main oxidizer conduits  110 , each of which has terminal portions concentrically surrounding an associated one of the fuel conduits  112  so as to mix the main fuel and oxidizer at an associated inlet  114 . In exemplary embodiments, 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 air/oxygen 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.  
      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). The predetonator fuel and oxidizer are then introduced through the associated ports filling the segment  84  and extending partially into the segment  86  (e.g., to near the midpoint) and advantageously just beyond the main fuel/oxidizer ports. The predetonator fuel and oxidizer flows are then shut off. An exemplary volume filled the predetonator fuel and oxidizer is 1-40%, more narrowly 1-20%, of the combustion conduit volume. The main fuel and oxidizer are then introduced, to substantially fill some fraction (e.g., 20-100%) of the remaining volume of the combustor conduit. The main fuel and oxidizer flows are then shut off. The prior introduction of predetonator fuel and oxidizer past the main fuel/oxidizer ports largely eliminates the risk of the formation of an air or other non-combustible slug between the predetonator and main charges. Such a slug could prevent migration of the combustion front between the two charges.  
      With the charges introduced, the spark box is triggered to provide a spark discharge of the initiator igniting the predetonator charge. The predetonator charge being selected for very fast combustion chemistry, the initial deflagration quickly transitions to a detonation within the segment  84  and producing a detonation wave. Once such a detonation wave occurs, it is effective to pass through 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  30  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  30  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  100  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.  FIG. 4  shows internal surface enhancements applied to the interior of one of the main segments  60 . The exemplary enhancement is nominally a Chin spiral, although other enhancements such as Shchelkin spirals and Smirnov cavities may be utilized. The spiral is formed by a helical member  120 . The exemplary member  120  is formed as a circular-sectioned metallic element (e.g., stainless steel wire) of approximately 8-20 mm in sectional diameter. Other sections may alternatively be used. The exemplary member  120  is held spaced-apart from the segment interior surface by a plurality of longitudinal elements  122 . The exemplary longitudinal elements are rods of similar section and material to the member  120  and welded thereto and to the interior surface of the associated segment  60 . Such enhancements may also be utilized to provide predetonation in lieu of or in addition to the foregoing techniques involving different charges and different combustor cross-sections.  
      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.  
      Various equipment operate under substantial differential pressure. For example, a positive pressure furnace will have interior pressures above ambient exterior pressures. This pressure difference imposes constraints on the ability to connect and disconnect soot blower components from the furnace while the furnace is in operation. Accordingly, a valve system may be provided for coupling soot blower equipment to the furnace.  FIG. 6  shows a first access conduit assembly  140  mounted in (or alternatively otherwise at) an aperture in the furnace wall. The access conduit assembly includes a valve assembly (valve) and a seal assembly (seal)  144 . In the illustrated embodiment, the access conduit assembly includes a spacer conduit  146  having an inboard (downstream) end flange  148  mounted relative to the furnace wall and an outboard (upstream) end flange  150  to which a downstream mating surface  152  of a body  154  of the valve is secured. A downstream surface  156  of a body of the seal is secured to the outboard/upstream surface  160  of the valve assembly body. The valve includes a gate  162  which may be manually or automatically (e.g., hydraulically or electromechanically) shifted between a closed configuration (e.g., position) blocking and sealing an aperture in the valve body and an open configuration at least partially clear of the valve aperture. The seal includes a sealing member (e.g., an O-ring)  164  having one or more sealing surfaces for sealingly engaging mating surfaces of an insertion portion of a combustion conduit. In the exemplary embodiment, the sealing surface is an inboard annular surface  166  of the sealing member which engages an outboard annular surface of a downstream insertion conduit  170 .  
      In the exemplary embodiment, the insertion conduit has an upstream flange mounted to a downstream surface  174  of a body  176  of a second valve  178 . The upstream surface  180  of the second valve body is mounted to a downstream main conduit section or segment of a soot blower combustion conduit (e.g., to the downstreammost segment  60  of  FIG. 2 ). As with the first valve, the gate of the second valve has open and closed configurations for sealing the insertion conduit relative to the main segments of the detonation conduit.  
      In a hot install operation, with the furnace operating and the first and second valves closed, the insertion conduit (preferably as a unit with the rest of the combustion conduit) may be brought into alignment with the access conduit and inserted, a distal portion adjacent its downstream end  182  passing through the seal and sealing therewith. Depending on the particular implementation, further translation of the insertion may be unnecessary. In that case, the valves may be opened to permit soot blasting. To remove the insertion conduit, the valves may be closed and the insertion conduit withdrawn from the seal assembly. In other implementations, however, after the initial sealing insertion, the first valve may be opened with the second valve closed and the insertion conduit further inserted so as to pass through the first valve and optionally into the spacer conduit.  FIG. 7  shows a situation wherein the end  182  has passed beyond the downstream end  190  of the spacer conduit and into the furnace interior. Thereupon the second valve may be opened to permit soot blower operation. Removal may be by a reverse of this process.  
       FIG. 8  shows an alternate system with a similar insertion conduit and second valve (thus similarly numbered) but an alternate access conduit assembly  200 . The access conduit assembly  200  includes a spacer conduit  202  having a similar downstream flange  203  to that of  FIG. 6  and a similar seal  204  to that of  FIG. 6  secured to its upstream flange  206  in the absence of an intervening or associated valve. A first valve  208  is alternatively mounted at/near the downstream end of the spacer conduit. The exemplary first valve  208  is a hinged gate valve having a gate  210  and a hinge  212  pivotally mounting the gate for rotation about a hinge axis  214  between a closed configuration (e.g., orientation) blocking/sealing the downstream end of the access conduit and an open configuration. The exemplary first operated valve actuated by contact with the insertion conduit. In the exemplary embodiment, the insertion process may bring the downstream end  182  of the insertion conduit into contact with a the upstream surface or backside  216  of the gate, so that physical contact pressure between the two rotates the gate into an open orientation ( FIG. 9 ), whereupon the second valve may be opened. For withdrawal, with the second valve closed, as the insertion conduit is withdrawn it permits the gate to close under spring bias or gravity bias. The exemplary engagement is of the downstream end  182  and exterior surface with a camming surface  218  of a projection  219  on the backside  216 .  
       FIG. 10  shows yet another modification wherein the access conduit assembly is similar or identical to the first access conduit assembly (thus similarly numbered) but the insertion conduit lacks an upstream valve. Instead, a hinged gate second valve  222  is formed at the downstream end  224  of the insertion conduit. Engagement of the insertion conduit with the access conduit may be as described relative to the first embodiment. Once installed ( FIG. 11 ), the second valve  222  may be opened by means of an actuation mechanism (not shown) such as a linkage or a cable within the wall of the insertion conduit.  
      Although illustrated heretofore with coaxial interior and exterior surfaces, the insertion conduit may have other arrangements (e.g., for directing the soot blower output in a desired direction). For example,  FIG. 12  shows an insertion portion  230  having an interior surface  232  which is a non-right cylindrical surface whose axis  520  is off-parallel (e.g., by 5-30°) to the axis  522  (which may be parallel to the axis/centerline  500 ) of the right circular cylindrical exterior surface.  FIG. 18  shows an access conduit  240  and insertion portion  242  with inner and outer surfaces coaxial about an axis  530  off-normal (e.g., by 5-45°) to the wall through which they extend.  
       FIG. 13  shows an access conduit assembly  300  including a gate type access valve  302  and a spacer conduit  304 . The spacer conduit is dimensioned to extend through a vessel wall aperture and is secured at its upstream end to the valve  302 . The body of the exemplary access valve  302  has an array of blind threaded holes  306  for rigidly mounting a conduit valve (discussed below) to the access valve.  
       FIG. 14  shows an insertion conduit/nozzle and conduit valve assembly  308 . The assembly  308  includes a double walled nozzle  310  which, in operation, may pass a cooling gas from upstream to downstream into the vessel between the nozzle walls (e.g., as is described in copending application attorney docket EH-10964 (03-434) filed on even date herewith and the disclosure of which is incorporated by reference herein as if set forth at length). The nozzle  310  has an upstream flange  312  which, upon assembly (as described below), is captured between upstream and downstream halves  314  and  316  of a body of the conduit valve. The conduit valve further includes a gate  318  and a pair of guide rails  320 . A gasket  322  may seal between the access valve body upstream face and the conduit valve body downstream face.  
      In an exemplary sequence of assembly, the access valve  302  has been preinstalled to the vessel (e.g., when the vessel is built or during a shutdown thereof). Remaining assembly steps may be performed hot (e.g., with the vessel in operation). The access valve is initially in its closed condition. One or more threaded studs  330  ( FIG. 13 ) may be engaged to the holes  306 . The gasket  322  may be put in place. The conduit valve body downstream half  316  may be put in place with counterbored holes receiving the studs and nuts  332  ( FIG. 15 ) secured to the studs within the counterbores so as to firmly bolt the valve half  316  to the access valve body. The nozzle  310  may initially be mounted to the gate  318  with the gate blocking the nozzle upstream end. The exemplary gate includes an aperture  334  initially not registered with the nozzle. The nozzle may be held to the gate by a mounting tool  336  on the upstream face of the gate and having bolts extending through the gate into the nozzle flange  312 . Threaded guide rods  338  may initially be secured at downstream ends to threaded holes in the valve half  316 . The guide rods may pass through holes in the tool  336  and the tool may be retained thereon by nuts  340 . The nuts may be tightened to gradually bring the nozzle  310  through the valve half  316  and into the access valve until forming a seal with access valve seals (not shown). The seal may be supplemented by connection of an air purge line (not shown) to a port in the valve half  316  to apply pressure between that half and the nozzle. When the nozzle downstream end reaches the gate of the access valve, the access valve may be opened. The pressure applied via the air purge lie helps prevent furnace gas leakage around the nozzle. Similarly, an additional air purge line (also not shown) may be connected to a port in the access conduit body or flange to further help prevent furnace gas leakage. Further tightening of the nuts  340  further inserts the nozzle  310  guided by the rods  338  and tool  336 . Eventually, the tightening brings the gate  318  into engagement with the valve half  316 , the gate downstream face lying flat against the upstream face of that valve half and optionally sealed by means of a seal (not shown). The guide rails  320  ( FIG. 16 ) may then be installed (e.g., by bolting to the conduit valve downstream half  316  to capture the gate  318  and prevent upstream shifting thereof). The tool  336  and threaded rods  338  may then be removed. The gate  318  will remain in place retained by the rails  320 . The conduit valve body upstream half  314  may then be installed via bolts  342  ( FIG. 17 ) extending around the gate into threaded apertures in the downstream half  316 . The upstream half  314  has threaded apertures  344  into which studs (not shown) may be inserted and the downstream flange of the adjacent conduit section secured. The remaining conduit sections may have been preassembled with the adjacent conduit section as a unit or may be further built up. With the conduit fully assembled, the conduit valve may be opened (e.g., via a handle  346  which translates the gate to align the aperture  334  with the conduit interior). Disassembly may be via a substantial reverse of this process. In alternate embodiments, the conduit valve may be omitted and upstream conduit sections secured directly to the access valve (with or without an insertion conduit).  
      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 cleaning 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.