Abstract:
An assembly for rotating and axially directing a high pressure spray hose and spray head to clean residue from the bores of thermal transfer tubes. The assembly includes a number of subassemblies that are concentrically aligned and mounted to rotate in synchrony and direct a high-pressure hose and spray head. A hose cleaning subassembly washes and/or brushes the hose exterior with a low-pressure spray. A hose drive assembly controls axial hose movement via driven gears and chains and four polyurethane pinch wheels that abut the hose. Spring tensioners control the wheel-to-hose pressure. A layering arm extends from a driven reel axle and stacks the hose in uniform layer onto an adjustable hub at a driven reel. The diameter of the reel hub can adjusted relative to an outer cage. The hose reel, axial hose drive and hose cleaner assemblies can be operated at speeds rotational speeds of 60 rpm to 650 rpm and whereby tubes from ½ to 6-inch diameters can be cleaned at rates of 1 to 80 feet per minute.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to cleaning equipment for tubes and piping and, in particular, to high-pressure water spray systems for cleaning the bores of tubes mounted in a variety of equipment, such as heat exchangers, falling pressure evaporators and the like. 
     Industrial piping systems of all types frequently require cleaning. A problem especially common to heat exchangers and evaporators is that over time the bore and exterior walls of the heat exchange tubes develop corrosion, scale and other undesired residue. The buildup of residue decreases and/or generally adversely effects the heat transfer efficiencies. Operating costs for fuel, in turn, increase. 
     Periodic maintenance is thus required to clean the tubes. Frequently the equipment must be taken off-line during maintenance. Such maintenance can be performed by plant personnel or outside contractors who are specially trained and use special purpose equipment to perform such tasks. It is desirable that any down time be minimized. The task is typically performed manually and is therefore costly and time consuming, especially for large heating and cooling plants. 
     A variety of techniques and types of equipment have been developed to clean the interior and exterior surfaces of pipes and particularly heat transfer tubes. Soot blowing and chemical shocking are two techniques. Another technique is to individually direct equipment into each tube to mechanically dislodge the residue from the tube walls. Some of the latter equipment uses rigid lances that either rotate and/or have rotating blades. U.S. Pat. No. 5,579,726 discloses a lance-based assembly that directs streams of high-pressure water to effect the cleaning. The latter system supports a rotating and axially directed lance from a frame that can be aligned to each tube. 
     High-pressure spray systems are also known that direct streams of water from a spray hose into each tube. Jetting Systems &amp; Accessories, Inc. sells one such system under the brand name “FLEX LANCER”. Another system is sold by Gardner Denver Water Jetting Systems, Inc., Houston, Tex. under the name “V” Drum Rotary Line Cleaner. The latter system provides a high-pressure hose and spray nozzle that are rotated and axially directed under power. Hose movement is directed with a hand-operated air controller and a pinch roller assembly that controls axial hose movement. Rotational movement is controlled via a separate motor. The hose is collected and dispensed from a rotating V-shaped spool or drum. Although offering advantages, the efficiency of the latter system is severely restricted by vibrations that occur due to unbalanced conditions that can occur at the equipment during typical use. Extreme vibrations have particularly been experienced at speeds approaching 60 rpm, which severely limits the utility of the equipment. 
     The present invention was developed to provide a more efficient high-pressure spray system. The assembly provides a hose mounted spray head that can be operated at rotational speeds in the range of 60 rpm to 850 rpm. Axial speeds in the ranges of 1 foot per minute to 80 feet per minute are also possible. At a nominal rotary speed of 300 rpm and an axial speed of 60 feet per minute the assembly is able to clean a typical 36-foot tube in one-fourth the time as the foregoing equipment. 
     The assembly is constructed to provide optimal balance along the entire drive train. The assembly also cleans the exterior surface of the spray hose as it is dispensed and collected from a driven spool or reel assembly. The reel assembly stacks the hosing in a tapered coil that is balanced to the longitudinal drive axis of the hose drive train. The hub of the reel assembly can be adjusted to accommodate different lengths and diameters of hose. 
     SUMMARY OF THE INVENTION 
     It is accordingly a primary object of the invention to provide a high-pressure tube cleaning assembly wherein a spray hose and spray nozzle can be directed at high rotational and axial rates by the assembly as the nozzle is directed through each tube being cleaned. 
     It is a further object of the invention to provide an assembly that includes a rotationally driven hose reel that arranges the spray hose in a fashion that avoids unbalancing the equipment relative to a longitudinal, rotational drive axis. 
     It is a further object of the invention to provide a hose reel having a conically tapered, hose collection hub mounted adjacent to a concentric outer cage and on which hub the hose is stacked in coils concentrically aligned to the longitudinal drive axis. 
     It is a further object of the invention to provide a hose cleaning assembly that cleans the hose as it is dispensed and collected. 
     It is a further object of the invention to provide a rotary mounted, air-controlled hose drive assembly having four polyurethane pinch-type drive wheels that axially direct the hose along the assembly&#39;s longitudinal drive axis and that is rotationally balanced relative to a hose reel. 
     It is a further object of the invention to provide a drive axle at the hose reel that is coupled to the hose drive assembly and from which axle a layering arm extends that aligns the hose relative to an adjustable hub at the hose reel. 
     It is a further object of the invention to provide a hose collection hub wherein the diameter and taper of the hose collection hub can be adjusted relative to the outer cage and center drive axle. 
     The foregoing objects, advantages and distinctions of the invention, among others, are obtained in the following disclosed tube cleaning assembly that has been particularly adapted for use in cleaning heat exchangers and falling tube evaporators. The invention can be adapted to other applications wherein the tool head is coupled to a high-speed, rotationally and axially directed supply conduit. 
     The subject tube cleaning assembly provides a mobile framework that attaches to on-site air and water supplies. The assembly includes a number of subassemblies that are concentrically aligned along a longitudinal drive axis to direct a high-pressure hose and spray head. The subassemblies are mounted to rotate in controlled synchrony at a number of pillow block bearings. 
     At a fore end, the hose and orifice containing spray head are directed through a hose cleaning subassembly that washes the hose with a low-pressure spray. The hose is axially directed to and fro with an air-controlled hose drive assembly. A hand-operated valve directs air to an air swivel and a pair of drive motors. Drive power is applied to a pair of driven gears and chains to follower gears attached to four polyurethane pinch wheels that abut the hose. Spring tensioners control the wheel-to-hose pressure and are able to axially direct the hose at speeds of 1 to 80 feet per minute. 
     The hose drive is coupled to a hose collection reel via a motor driven reel axle. A layering arm extends from the axle and directs the hose onto an adjustable hub at the reel. The hose is preferably stacked in a single layer. A swivel at the opposite end of the reel axle supplies high-pressure water in the range of 3,000 psi to 50,000 psi to the hose. 
     The diameter of the hub at the hose reel can adjusted relative to an outer cage. The layering arm and hub cooperate to stack the hose in concentric layers relative to the longitudinal drive axis of the assembly to assure a balanced loading. The reel, axial hose drive and hose cleaner assemblies can be operated at rotational speeds in the range of 60 rpm to 650 rpm. The assembly is thereby able to clean tubes from ½ to 6-inch diameters at rates of 1 to 80 feet per minute. 
     Still other objects, advantages, distinctions and constructions of the invention will become more apparent from the following description with respect to the appended drawings. Similar components and assemblies are referred to in the various drawings with similar alphanumeric reference characters. Various features of the invention may also be configured with other features in different combinations. The description should therefore not be literally construed in limitation of the invention. Rather, the invention should be interpreted within the broad scope of the further appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective drawing shown in partial cutaway and exposing the various subassemblies of the high-pressure spray cleaning equipment of the invention. 
     FIG. 2 is a detailed perspective view to the hose cleaner and air-driven hose drive and wherein the spray head is also shown in cutaway in a typical heat exchanger tube. 
     FIG. 3 is an enlarged plan view of the hose drive assembly 
     FIG. 4 is a perspective view to the hose collection reel with a length of spray hose arranged on the hub and also showing length adjustable link arms and end hoops of the hub. 
     FIG. 5 is a perspective view to the aft end of the hose reel showing the adjustable link arms and end hoops of the outer cage. 
     FIG. 6 is a perspective view shown in partial section to an alternative hose collection reel having an outer cage and to which a number of removable upright strut plates are attached to accommodate differing hose lengths and diameters. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 a perspective drawing is shown to the portable, high-pressure spray cleaning assembly  10  of the invention. The assembly  10  finds particular application for on-site cleaning of heat transfer tubes in commercial and industrial heat exchangers. A spray head  12  having a desired number of orifices  14 , reference FIG. 2, directs a number of high-pressure (e.g. 200 to 50,000 psi) streams of water against the bore walls of a heat transfer tube or pipe  16  to dislodge and wash scale and residue from the tube walls  16 . The spray head  12  is rotated and axially extended and retracted from the tube  16  to most advantageously direct the spray streams from the orifices  14 . 
     A suitable length of hose  18  is secured to the spray head  12  and is deployed and stored at a hose spool or collection reel assembly  20 . The hose  18  is constructed to withstand the normal anticipated working conditions and pressures. The hose  18  is typically constructed of several layers of water impermeable material in numerous wound wrappings and may contain wraps or bands of wire, KEVLAR and the like. The diameter of the hose  18  can be adjusted as desired (e.g. ⅛ to 1 inch) depending upon the application, diameter of tube  18  and desired working pressures. 
     The hose  18  is contained in a length of a flexible, tubular cover piece  22  that is secured to a hose washing assembly  24 . The hose  18  is free to slide and rotate within the cover piece  22 . The cover piece  22  particularly protects the hose  18  as an operator directs the assembly and hose  18  about the work site and as the hose  18  is manipulated by the operator and fitted to each tube  16  being cleaned. 
     A support frame  26  provides a number of wheels  28  and handles  30  that make the assembly  10  portable. Several stanchions  32 ,  34  and  36  rise from the frame  26  to support a number of pillow block bearings  38 . A forward, hollow stub axle  40  and a partially hollow drive axle  42  are contained by the bearings  38  and permit rotation of a coupled axial hose drive assembly  44  and the hose reel  20 . The horizontal spacing between and vertical offset of the stanchions  32 - 36  can be adjusted depending upon the size and length of hose  18  that is being deployed. 
     With attention to FIG. 2, the hose cleaning assembly  24  extends forward of the stanchion  32  from the stub axle  40 . The hose cleaning assembly  24  essentially comprises a manifold  45  having bolted cylindrical sections head and backing pieces  46  and  48  that directs several low-pressure streams of water onto the outer walls of the hose  18 . A number of flow channels (not shown) are formed into head and backing pieces  46  and  48  that are secured with several fasteners  49 . A fitting  50  couples a water supply line  52  to the manifold  45 . The water is directed from a central bore  54  through which the hose  18  passes. One or more brushes  55  can be secured and concentrically aligned to the headpiece  46  and the hose  18  to scrub debris during hose cleaning. 
     The hose  18  is directed axially through the cleaning assembly  24  by the hose transport or drive assembly  44 . The hose drive assembly  44  is mounted to rotate between the stanchions  32  and  34  and is covered by a safety cage  45 . The hose reel  20  is mounted to rotate between the stanchions  34  and  36 . Each of the assemblies  20 ,  24  and  44  are concentrically aligned to the center longitudinal drive axis of the assembly  10  and relative to which the hose  18  is particularly coaxially and concentrically aligned. Hose movement is thus balanced to the drive axis and the enhanced operating speeds are possible. 
     With attention to FIGS. 2 and 3, an air swivel  60  is secured to the forward end of a two-section, split drive frame  62  of the drive assembly  44 . The frame assembly  62  supports four polyurethane pinch-wheels  64  that grip the hose  18 . Adjusting bolts  66  and springs  68  control the tension or pinch pressure of the wheels  64  against the hose  18 . Two pairs of the pinch-wheels  64  (only two of which are shown) are arranged  1800  opposite each other to overly each other. The wheels  64  can also be positioned in other arrangements. The wheel material can also be varied as desired relative to the hose  18  to provide optimal friction and wear tolerance between the wheels  64  and hose  18 . 
     A hand-operated valve  70  controls airflow from an air supply  69  through the swivel  60  and to a pair of air driven motors  72  secured to the frame  62 . A drive axle  74  of each motor  72  is coupled to a drive gear  76 . Power is directed via a chain  78  to a pair of follower gears  80  that are coupled to axles  82  that are secured to each drive wheel  64 . The valve  70  is controlled to bi-directionally direct the hose  18  with a reciprocating motion at a desired axial speed to achieve proper tube cleaning, hose deployment and collection. A coupler  84  at the aft end of the frame  62  secures the frame  62  to the drive axle  42 . Although an air powered transport drive is presently used, hydraulic, electric or other types of power drives can be adapted to the assembly  44 . 
     The rate of movement of the hose  18  through the hose drive assembly  44  is regulated in relation to the rotational speed of the reel  20  to assure that the hose  18  is synchronously extracted and stacked to avoid kinking, strain or slack at the reel  20 . The relative speeds also take into account the operating rigidity of the hose  18 , which is relatively stiff when placed under the pressures discussed herein. Any of the latter conditions can unbalance the assembly  10 . During a cleaning stroke, when the hose  18  is extended into a tube  16 , the assembly  44  and reel  20  rotate at a slower speed. During hose retraction from the cleaned tube  16 , when there is relatively little resistance to motion, the assembly  44  and reel  20  are rotated faster. The operator via the valve  70  manually controls the relative rates of rotation. 
     The relative rates are established empirically as required to meet the working conditions by regulating the air pressure at the valve  70  in relation to the constant drive power provided to the reel  20 . An electric motor and V-belt/pulley transmission determine the rotational speed of the reel  20  which are discussed in more detail below. A variety of automatic control assemblies can also be adapted to the assembly  10  to obtain automatic speed regulation, such as by monitoring the condition of the hose  18  at the reel  20  via appropriate sensors. Sensor feedback can be directed to the speed regulators at the assembly  44  and reel  20 . 
     For jobs requiring multiple assemblies  10 , cleaning time can be reduced and equipment operation improved by coupling the several assemblies  10  to the single air supply  69  and operating the assemblies  10  in complementary fashion. That is, as the hose  18  of one assembly  10  is directed in a cleaning stroke, the hose  18  of another assembly  10  is collected. The demand on the air supply is therefore substantially continuous. 
     With attention to FIG. 4, the hose  18  passes through a bore  86  at the forward end of the drive axle  42  and a bore  88  of a layering arm  90  that extends from the side of the axle  42 . The layering arm  90  directs the hose  18  onto a center hub  92  of the reel  20 . The hub  92  is concentrically positioned relative to an outer cage  94  such that the hose  18  is deposited in a single, layered coil that is concentric to the drive axis of the assembly  10 . The changing weight of the hose  18  and contained liquid is thus dynamically balanced to the assembly  10 . The reel assembly  20  can also be constructed to provide for multiple side-by-side coil wraps. For example, the diameter of the hub  92  may be constructed to expand and contract dynamically via centrifugal force and/or automatically with a controlled linkage. The arm  90  can also be mounted to pivot relative to the hub  92  to control layering. In the latter regard, the arm  90  can be hinged to pivot at the axle  42  and the linkage arm  93  can be constructed in two telescoping sections  89 ,  91 . 
     FIG. 4 also depicts adjustment features of the reel assembly  20 . That is, the fore and aft diameters of the hub  92  can be adjusted at the interconnected, telescoping hoop pieces  96 ,  97  and length adjustable spoke pieces  98 ,  99 . Proper adjustment of the hub  92  can be arranged to be cylindrical or provide a taper. The hub  92  is presently constructed to taper inward as it extends forward and accommodates a single, stacked coil of hose  18 . 
     The hoops  96 ,  97  and spoke pieces  98 ,  99  are adjusted in concert with a number of fasteners  100 . Slots  102  in the spoke pieces  98 ,  99  overlap the fasteners  100 . The outer cage  94  can also be constructed with adjustable hoops  101 ,  103  and spoke pieces  104 ,  105  relative to slots  102  and fasteners  100  as shown by representative example at FIGS. 4 and 5. Still other adjustable arrangements at the layering arm  90  and hub  92  can be provided to balance multiple coils, yet maintain a concentric assembly. 
     FIG. 5 depicts a drive pulley  110  that is secured to the aft end of drive axle  42 . Rotational drive power is supplied to the axle  42  from another pulley attached to via a drive motor  114  and belt  116 . The rotational speed can be varied as desired by adjusting the relative diameters of the motor pulley to the drive pulley  110 . The assembly  10  has been operated at speeds in excess of 400 rpm and approaching 650 rpm without experiencing vibration. This is in contrast to maximum operating speeds of 60 rpm for competitive assemblies. 
     A bore  118  at the aft end of the drive axle  42  is coupled to a swivel  120  and a high-pressure water source  121 . Water is directed through the swivel  120 , axle  42 , a stub pipe  122  and coupler  124  to the hose  18 . The working spray pressures can be varied as desired. Presently, pressures in the range of 4,000 psi to 36,000 psi are preferred when cleaning tubes found in boilers and evaporators. 
     FIG. 6 discloses an alternative reel assembly  120  that can be adjusted with relative ease to accommodate hoses  16  of different diameter and length. The reel assembly  120  provides a base  122  that is defined by a number of annular bands  124  and a center collar piece  126  that mounts to the axle  42 . A number of inner and outer cage bands  127  and  128  are vertically offset from the base  122 . The base and cage bands  124 ,  126  and  128  are coupled (e.g. welded) to a number of upright, planar strut plates  130  at notches  132  let into the peripheral edges of the plates  130 . 
     Only one strut plate  130  is shown, but it is to be appreciated that several other identical plates  130  are mounted to align with notches  134  at each of the bands  124  and mate with the bands  124 ,  127  and  128 . The assembly  120  provides for eight plates  130 , but the number of plates  130  can be varied as desired. 
     A hose collection channel  136  is defined at each plate  130  between an outer arm  135  and inner hub  140 . A number of coils of the hose  18  are shown as they appear when layered in the channel  136 . The channels  136  project at an acute angle relative to the base  122  as they extend inward toward the collar  126  to define a tapered hose storage space. 
     The assembly  120  can be constructed of a variety of materials, although aluminum is presently preferred to reduce weight. Weight relief holes  142  are also provided in the plates  130 . 
     The channel  136  is constructed oversized to nominally accommodate hoses from ¼ to 2-inch diameters. When a smaller diameter hose  18  is being used, a frustum shaped spacer  144  is also mounted in the channel to take-up space and assure the hose is layered in uniform coils. 
     The strut plates  130  thus define several vertical ribs that collectively capture and contain the hose  18  in relation to the layering arm  90 . The reel assembly  120  can be adapted to accommodate hoses  16  of different diameter and length upon attaching an appropriate spacer  144 . 
     While the invention has been described with respect to several assemblies and considered improvements or alternatives thereto, still other constructions may be suggested to those skilled in the art. For example, the hose washing assembly  24 , axial drive assembly  40  and/or adjustable reel assembly  20  can be used in combination or can be provided in other cleaning system arrangements. The cleaning equipment can include other controls for adjusting the rotational and axial operating speeds. Sundry safety controls can also be provided. The foregoing description should therefore not be literally construed and should instead be construed to include all those embodiments within the spirit and scope of the following claims.