Multi-Lance Tube Cleaning System Having Flexible Portions

1. Field of the Invention

The present invention relates to an apparatus for cleaning the interior of tubes used in heat exchanger bundles. More particularly, the present invention relates to an apparatus capable of simultaneously cleaning the interior of several curved tubes within a heat exchanger bundle on site.

2. Description of the Prior Art

Heat exchanger tube bundles are used for the transfer of heat from a fluid media passing through a series of conduits. During this process, carbonaceous and calcareous deposits will form on the interior of the individual tubes and debris and other dirt will collect on the surface of the individual tubes. Therefore, in order to maintain efficient operation, it is necessary to periodically remove the tube bundles and clean the interior and exterior of the tubes.

One method of cleaning the interior of heat exchanger tubes includes the progressive insertion of a small diameter tube, known as a lance, into the heat exchanger tube and pumping high pressure water through the lance to clean the interior of the tube. The water pressure in a lance may easily exceed 10,000 psi and flow rates in excess of 100 gallons per minute. Prior art devices called for the lance to be manually operated and advanced into the exchanger tube. It will be appreciated that the manual operation of a lance is unsatisfactory for a number of reasons. First, the operator is required to overcome the force of the water pressure when inserting the lance into the tube. Further, should the lance wall rupture, an operator may be injured by the high pressure water flow. Similarly, an operator may be injured by back-splash from the lance during the insertion of the lance in the tube. Lastly, the manual operation of a lance is time consuming and costly as only one lance may be used in manual operations.

Various mechanical devices have been used in an effort to overcome the above deficiencies in cleaning the interior of heat exchanger tubes. U.S. Pat. No. 3,903,912 to Ice, et al. discloses a multiple lance cleaning system, including lance positioning and drive means and exposed lance tubes. However, the use of exposed lance tubes continues to pose a danger to an operator should a lance wall rupture. U.S. Pat. No. 3,817,262 to Cradeur also discloses a multiple lance cleaning system having a lance positioner and drive system and exposed lance tubes. However, as in the Ice disclosure, the operator is still exposed to the danger of potential lance tube rupture.

U.S. Pat. No. 3,901,252 to Riebe discloses a multiple lance system including a lance drive and enclosed lance tubes, manifold and water lines. However, Riebe does not disclose a lance positioning system capable of readily positioning the lances and lance drive into a multitude of tubes within the heat exchanger bundle nor does it disclose a system for retracting the water pressure line. U.S. Pat. No. 4,856,545 to Krajicek disclosed a multi-lance tube cleaning system having a lance drive means, lance tubes and manifold and multiple high pressure water lines within an enclosed structure. The disclosure called for the cleaning structure to be positioned by a crane mounted on a truck or by other mobile crane, tractor or skid. However, there are a number of disadvantages, i.e., as the lances are moved forward the center of gravity of the structure may shift which could result in misalignment and unnecessary stress on the lance tubes.

Further, none of the above devices disclose a means for cleaning tubes wherein the tubes are arranged in a curved path. All of the above disclose a rigid lance incapable of traversing a curved path. A heat exchanger tube may follow a serpentine or other curved path. One example of a curved path includes inter-tube connections, such as U shaped connectors which permit flow between various tubes within the heat exchanger bundle.

Accordingly, there exists a need for an improved tube bundle cleaner having enclosed tube lances, the lances being capable of traversing a curved path, means for transporting water to the lances and for accurately supporting and positioning the lances during operation, and means for retracting the water pressure line in an efficient and thorough manner. While there are other disclosures directed to the cleaning of the interior of heat exchanger bundles (such as U.S. Pat. Nos. 3,589,388; 2,494,380; 1,694,371; and 620,224), none disclose or suggest a multi-lance cleaning system having enclosed lances capable of traversing a curved path, manifold and an independent means for positioning the lance cleaning system.

The present invention relates to a multi-lance apparatus for cleaning the interior of tubes within a heat exchanger tube bundle having an elongate housing, a moveable high pressure water manifold within the housing, a single conduit connecting the manifold to a high pressure high, volume water source and means for storing the conduit. The apparatus further includes a plurality of lances removably connected to the manifold a portion of the lances being capable of traversing a curved path, means for moving the manifold within the housing and means for supporting and guiding the lances during operations and storage. The present invention also includes a means for positioning and supporting the housing with respect to a tube bundle to be cleaned.

A better understanding of the present invention may be had by reference to the following drawings and contained numerals therein of which:

FIG. 1 is an elevational view of the preferred embodiment;

FIG. 2 is a top view of the preferred embodiment;

FIG. 3 is an end view partly in section of a portion of the present invention;

FIG. 4 is a front view partly in section of a portion of the present invention;

FIG. 5 is a top view partly in section of a portion of the present invention;

FIG. 6 is a detailed sectional view taken along line 6--6 of FIG. 5 showing the lateral transport mechanism of the present invention;

FIG. 7 is a detailed sectional view taken along line 7--7 of FIG. 6 showing the lateral transport mechanism of the present invention;

FIG. 8 is a detailed elevational view partly in section of the vertical transport mechanism of the present invention;

FIG. 9 is a detailed sectional view taken along line 9--9 of FIG. 8 showing the vertical transport mechanism of the present invention;

FIG. 10 is a cross-sectional view of the tube cleaning apparatus and spool portion of the preferred embodiment;

FIG. 11 is a cross-sectional view taken along line 11--11 of FIG. 10 showing the tube cleaning apparatus of the preferred embodiment;

FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 10 showing the spool portion of the preferred embodiment;

FIG. 13 is a cross-sectional view of the manifold portion of the preferred embodiment;

FIG. 14 is an end view of the manifold portion of the preferred embodiment;

FIG. 15 is a cross-sectional view of the flexible lance adapter assembly;

FIG. 16 is an end view of the flexible lance assembly guide plate;

FIGS. 17A and 17B are end views of the indexing block of the flexible lance adapter assembly;

FIG. 18 is cross-sectional view of the preferred embodiment of the present invention showing the flexible lances traversing a curved path; and

FIG. 19 is a perspective view of the preferred embodiment in a vertical operational mode.

FIGS. 1 and 2 are side and top views of the preferred embodiment of a multi-lance tube cleaning system as disclosed in U.S. patent application No. 490,776. A tube bundle "B" is disposed on rollers which are part of a tube bundle support and rotating device "R. " The device "R" is disclosed in pending U.S. patent application No. 489,001. Lance assembly 100 is shown in close proximity to tube bundle "B." A plurality of hollow, high strength, lances "L" are generally shown as being disposed in the rigid lance assembly 100. A lance indexing assembly 150 is shown affixed to the end of the lance assembly 100, adjacent to the tube bundle "B." Further, the lances "L" are shown as being in communication with a manifold "M" within the lance assembly 100. Spool assembly 200 is removably attached and in close proximity to lance assembly 100. The spool assembly 200 is used to store a high pressure flexible water line (218 in FIG. 10) which is in communication with manifold "M" in rigid lance assembly 100. The spool assembly 200 is itself connected to a high pressure, high volume water source by means of hose "H" as shown in FIG. 2. The lance assembly 100 and the spool assembly 200 are supported by a positioner assembly 300 which supports and positions the lance assembly 100 and spool assembly 200 relative to the tube bundle "B" to be cleaned. The positioner 300 is capable of moving the lance assembly 100 and spool assembly 200 horizontally (or laterally) and vertically. Also shown in FIG. 1 is a remote control pendant 30. The control pendant 30 is intended to control a high pressure water source and hydraulic fluid flow used to position and power the present invention. While the remote control pendant may be configured to control any suitable high pressure water source and hydraulic flow, it is contemplated that the present invention, including the remote control pendant 30 has been specifically configured to operate with the high pressure water source and hydraulic pressure source described in U.S. patent application No. 489,001, hereinafter referred to as the "water pressurizing unit." Further, the control pendant 30 in the present invention is interconnected with the positioning and spool assemblies 300 and 200 in a like manner as the remote control pendant described in U.S. patent application No. 489,001.

Referring to FIGS. 3 and 4, the positioning assembly 300 is comprised of a generally rectangular base frame 302. Preferably, the base 302 is formed from metal channel members 304 and 306. Members 304 make up the side base channels and members 306 make up the front and rear members of the base 302. Base members 304 and 306 may be connected using mechanical means, such as nuts and bolts.

Referring to FIG. 5, base members 304 extend past base members 306. The extra length of base members 304 provides an attachment point for flared leveling feet 308. A more detailed view of leveling feet 308 may be obtained from FIG. 8. The feet 308 have a threaded shaft 310 attached to the upper end of said feet 308. Preferably, the leveling feet 308 and shaft 310 are a unitary body. The shaft 310 extends upward through a hole in base member 304 and is threaded into nut 312 affixed to base member 304.

Referring again to FIGS. 3 and 4, affixed to base 302 are four vertical frame members 314. Generally, the vertical members 314 are of a box construction. A plurality of gussets 316 and cross braces 318 are attached to base 302 and vertical members 314 to provide additional stiffness and rigidity to the positioning assembly 300. A vertical cap 320 of a rectangular shape is affixed to the top of each vertical member 314. Four vertical guide shafts 322 are mounted in proximity to vertical members 314. Referring now to FIG. 8, the guide shafts 322 are threaded on each end and removably fixed to base 302 by nuts 324/326.

Referring still to FIGS. 3, 4 and 5, a generally rectangular guide frame 330, comprised of I-beam members 332 and 334, is provided to assist in vertically positioning the cleaning apparatus of the present invention with respect to tube bundle "B" as shown in FIG. 1.

Referring back to FIG. 8 and also FIG. 9, a threaded shaft 336 is mounted in each of the vertical members 314. The shaft 336 thread may be an acme or other suitable thrust bearing thread. The shaft 336 is supported and retained by bearing 338 affixed to the frame 302 and by similar bearings mounted in vertical caps 320 (not shown). Affixed to the bottom of shaft 336 is a worm gear follower 340. The shaft 336 is rotated by a hydraulic motor 342 as shown by phantom lines. The hydraulic motor 342 output shaft 344 is coupled to a drive shaft 346. Mounted on drive shaft 346 are two worm gears 348. The worm gears 348 engage worm gear followers 340 mounted on threaded shafts 336. The drive shaft 346 runs the length of base member 306 and is supported and retained by bearing blocks 350 (FIG. 4) and bushing 352 (FIG. 9) which is mounted on the inside face of vertical member 314, and bearing 354 which is mounted in the outside face of vertical member 314. As may be seen in FIG. 3, two motors 342, shown in phantom, are mounted at the front " F" and rear "R" of positioning assembly 300.

With reference to FIGS. 4, 8 and 9, the rotational output of motor 342 is coupled to drive shaft 346. The worm gears 348 mounted on drive shaft 346 are in rotational contact with worm gear followers 340 and thereby rotate threaded shafts 336.

Affixed to guide frame 330 at each corner are guide carriages 356. As may be seen in FIG. 9, guide carriage 356 is adapted to fit within vertical member 314 through an open channel in vertical member 314. Referring again to FIG. 8, a threaded nut 358 adapted to mate with threaded shaft 336 is mounted on guide carriage 356. In the illustrated embodiment, threaded nut 358 is depicted as a separate entity. However, it is understood that a female threaded adapted to mate with threaded shaft 336 may be machined directly into guide carriage 356. Guide carriage 356 is also in slidable contact with vertical shafts 322. As shown in FIG. 8, the vertical shaft 322 passes through a hole in guide carriage 356 in which is mounted a nylon guide bushing 360. It is understood that other suitable materials, such as brass, may be used to form guide bushing 360.

Thus, the rotational output of hydraulic motors 342 rotates drive shafts 346 and worm gears 348, which, in turn rotate threaded shafts 336. The guide frame 330 is thus positioned vertically as it moves in response to the rotation of threaded shaft 336 by means of threaded nut 358. Further, the vertical shafts 322 provide additional stability to the movement of guide frame 330.

Referring now to FIGS. 5, 6 and 7, a lateral positioning means is adapted to be mounted on guide frame 300. A carrier beam 362 is adapted to be slidably mounted on guide frame members 332. The carrier beam 362 is adapted to be removably connected to a carrier block 364, which may be manufactured from nylon or other suitable material having a sufficiently low coefficient of friction. As may be seen in FIG. 7, the carrier block 364 is adapted to rest on the top flange of guide frame member 332. Carrier retainers 366 are adapted to be removably attached to carrier block 364 and are in close proximity to the inside face of the top flange of frame member 332. The carrier block 364 and carrier retainers 366 are adapted to mate with carrier beam 362 by means of nuts and bolts 368. The carrier beam 362 is thus retained in close slidable contact with frame member 332. Further, the carrier blocks 364 and retainers 366 may be readily serviced or replaced when they become worn.

Referring now to FIG. 5, a hydraulic motor 370 is mounted on frame member 334. The motor 370 is coupled to a gear box 372 which transfers the output to threaded shaft 374 and threaded shaft 376 which is substantially at a right angle to shaft 374. The thread on shaft 374 may be an acme or other suitable thrust bearing thread. Shaft 376 is in turn coupled to a second gear box 378, which transfers the rotation of shaft 376 substantially ninety degrees to a second threaded shaft 375. Threaded shafts 374 are supported at their distal ends by bearing blocks 380 affixed to frame member 334. Threaded nuts 382 having a thread mating the thread of shafts 374 and 375 are affixed to the web of carriage beam 362 in proximity to its distal ends, threaded shafts 374/375 passing therethrough. In the illustrated embodiment, threaded nuts 382 are shown to be adapted to fit within and be affixed to carriage beam 362 by means of nuts and bolts 384. However, it may be understood that a threaded nut 382 of different configuration may be affixed to carriage beam 362 by other means. The output of motor 370 thus drives threaded shafts 374/375 causing carriage beam 362 to move laterally along frame member 332 in the direction of arrows 377. Accordingly, it will be appreciated that the positioning assembly is capable of positioning carriage beam 362 horizontally with respect to a tube bundle "B" as shown in FIGS. 1 and 2. Further guide frame 330 and carriage beam 362 operate to position the rigid lance 100 and spool 200 assemblies horizontally and vertically.

Referring to FIG. 10, lance assembly 100 and spool assembly 200 are shown. With reference to lance assembly 100, a hollow elongate housing 102 is affixed to a shorter base 104 which comprises a web 103 and a top 105. In the preferred embodiment, cross-sectional housing 102 is shown as cylindrical in cross-section (See FIG. 11). However, it is understood that the cross-section of housing 102 may vary without departing from the spirit of the invention. In the preferred embodiment, base 104 is shown as being welded to housing 102. Base 104 is adapted to be removably attached to carriage beam 362, depicted in FIG. 1. The base 104 may be attached to carriage beam by means of nuts and bolts, latches or other suitable mechanical means. An elongate support member 106 is affixed to housing 102 opposite base 104. Support member 106 rests on carriage beam 362. A manifold 108 is slidably mounted in housing 102.

Referring to FIG. 13, manifold 108 is comprised of a central metal body 110 having an axial bore 112 therethrough. One end of bore 112 is adapted to be removably connected to a high pressure water line. It is understood that any references to water as a high pressure cleaning fluid is meant to include water, a cleaning fluid, or any soluble combination thereof. All further references to water are meant to include such cleaning fluids. Body 110 includes a sealing thread 114 in the central bore 112. Opposite the threaded end of body 110, a coaxial counterbore 116 is machined in bore 112. A lance plate 118 is mounted adjacent to the machined counterbore 116 and in sealing contact with body 110. Lance plate 118 may be maintained adjacent to manifold body 110 by means of drilled and tapped holes or other suitable mechanical means. Lance plate 118 includes a plurality of apertures 120 passing therethrough and a plurality of counterbores 122 adjacent to body 110. The lance plate counterbores 122 are adapted to mate with the counterbore 116 in body 110 such that the lance plate holes 120 are in fluid communication with manifold central bore 112. The lance plate 118 further includes internal threads 124 adapted to receive lances 126 and mate with threads 128 thereon. It is contemplated that the internal diameter of lance plate holes 120 is approximately equal to the inside diameter of lances 126. The lance plate 118 and body 110 are fitted into a manifold shield 130, which is made from a suitable low friction material, such as teflon-coated nylon. The manifold shield 130 is retained to the manifold body 110 by means of machine screws 132.

Referring back to FIG. 10, lances 126 are thereby removably attached and in fluid communication with manifold 108. Lances 126 have relatively thin walls and are manufactured from a high strength stainless steel or other suitable material. Lances 126, when mated with manifold 108, are approximately the length of housing 102.

Referring now to FIGS. 1, 2, 10, and 12 and with particular reference to FIGS. 10 and 12, the present invention also includes a spool assembly 200 for the storage of the high water pressure hose used to provide water under pressure to lances 126. Spool assembly 200 comprises a housing 202 which is removably fixed to lance housing 102 and support member 106. In the illustrated embodiment, spool housing 202 is secured to housing 102 by means of nuts and bolts 204. Rotatably mounted in spool housing 202 is spool 206. Spool 206 comprises a spindle 208, shaft 210, circumference plate 220 and side plates 222. Spool spindle 208 further includes a blind hole 211 therein along the longitudinal axis of spindle 208 and a radial passageway 212 therethrough. Blind hole 211 and radial passageway 212 are in fluid communication with each other. The radial passageway 212 is adapted to be removably connected to a water pipe 214 which is itself connected to union 216. Radial passageway 212 includes internal threads 213 adapted to sealingly mate with threads 215 on pipe 214. A high pressure water hose 218 is adapted to sealingly mate with union 216. The water hose 218 is a semi-rigid high pressure water hose capable of pressures in excess of 10,000 psi. A typical water pressure hose 218 would be Model 4025 ST or equivalent manufactured by Rogan-Shanley, Inc. of Houston.

As may be seen in FIG. 12, water hose 218 is reeled onto the spool 206 and is retained by spool circumference plate 220 and side plates 222. The hose 218 is but a single hose; it appears to be a double hose in FIG. 12 because it is wrapped twice around the spool since the view is taken along line 12--12 of FIG. 10. Hose 218 is retained by a plurality of fixed rollers 224 mounted within spool housing 202. As illustrated, the rollers 224 are rotatably mounted on pins 226 which are affixed to housing 202. Further, the surfaces of rollers 224 and plate 220 are angled to encourage the hose 218 to wrap around plate 220 in an adjacent manner rather than on top or otherwise tangle up. Thus, the hose 218 is reeled and retained about spool 206 without exceeding the minimum bend radius for hose 218. Affixed to spool spindle 208 is a rotating union 228 (FIG. 2) which is removably connected to union 230 which is itself connected to a high pressure water source through hose "H." Referring to FIGS. 1 and 10, coaxially affixed to spindle 208 is spool shaft 210. Mounted on spool shaft is a drive pulley 232. Mounted external to spool housing 202 is a hydraulic motor 234 having a drive pulley 236. Motor drive pulley 236 and spool drive pulley 232 are in rotational communication by means of drive belt 238. It is understood that the embodiment includes the use of drive gears and an endless chain to accomplish the transfer of rotational movement from motor 234 to spool 206. Further, motor 234 may be mounted external to spool housing 202 in a manner such that a motor drive gear would be in direct rotating contact with a drive gear mounted on spool shaft 210.

When hydraulic drive motor 234 is activated, the spool 206 is caused to rotate, thereby extruding or retracting hose 218. As may be seen in FIG. 10, hose 218 travels out of spool housing 202 and into the lance housing wherein it is removably connected to the manifold body 110 (FIG. 13). Thus, rigid lances 126, manifold 108 and hose 218 are in fluid communication with each other. Further, as hose 218 is semi-rigid, it serves in the illustrated embodiment to advance and retract manifold 108, thereby advancing and retracting rigid lances 126. Accordingly the illustrated embodiment provides for a common means of storing the high pressure water hose 218 and moving rigid lances 126.

It will be appreciated that the size of a heat exchanger tube and the manner in which the tubes are arranged within a tube bundle affect the required spacing between the tubes. Consequently, it is necessary that the present invention be capable of adjustment for various tube sizes and spacing. The tube orientation within a tube bundle is generally either of a "square" or "triangular" pitch or alignment. Accordingly, it is necessary to align the lances 126 with the tube alignment. In order to accomplish this objective, the present invention includes an indexing assembly which is adapted to compensate for variations in tube size and orientation.

Referring now to FIGS. 15, 16, and 17A and B the lance indexing assembly 150 includes a rearward indexing guide plate 152. The indexing guide plate 152 is mounted external and coaxial to housing 102 in a suitable mechanical manner. The guide plate 152 has a plurality of apertures 154 passing therethrough. The pattern formed by the guide plate holes 154 is similar to that found in lance plate 118 (see FIG. 14); however, guide plate holes 154 are of a sufficient diameter to permit lances 156 to pass through. Guide plate holes 154 are adapted to receive a plurality of guide tubes 166 which have sufficiently large internal diameter to permit lances 126 to pass through. Guide tubes 153 may be affixed to guide plate 152 in any suitable fashion such as a threaded connection. Guide tubes 156 are bent to alter the pattern or "pitch" and the spacing between adjacent tubes 136 to match that of the tubes within tube bundle "B."

However, the angle of the bend along the centerline of guide tubes 156 is sufficiently small to permit lances 126 to pass through the guide tube 136 bend without unduly stressing the walls of, or plastically deforming, lances 126. A second forward guide plate 176A/B which is adapted to reflect either square or triangular pitch and tube diameter for the particular tube bundle "B" being cleaned is fitted between guide tubes 136. In FIG. 17B forward guide plate 176B is shown as having a square pitch. FIG. 17A illustrates a forward guide plate 176A having a triangular pitch. Thus, the present invention may be readily adjusted for variations in tube bundle size and orientation in a relatively short period of time. Further, as guide tubes 156 are substantially parallel to the centerline of the housing 102, the centerline of lances 126 as they enter the tubes are substantially parallel to the axis of the tubes to be cleaned. Accordingly, lances 126 are less likely to be damaged during cleaning operations which call for the lances 126 to be offset from their original centerline.

Referring still to FIG. 15, housed within each guide tube 156 is a flexible lance 158. The flexible lance 158 is comprised of a high pressure flexible hose 160 such as 2004 Stv or 2005 Stv hose manufactured by Rogan-Shanley of Houston, Tex. A hose end connection 162, is affixed to the end of flexible hose 160 nearest lance housing 102 and is adapted to mate with lance 126. As shown, the hose end connection 162 includes internal threads 164 adapted to mate and seal with external threads 127 on lance 126. At the far end of flexible hose 160 is a second hose end connector 166 which is adapted to mate with hydroblasting tip 170. As shown, hose end connector 166 includes internal threads 168 which are adapted to mate with external threads 172 on hydroblasting tip 170. Hydroblasting tip 170 is used to deliver a high pressure water stream to the interior of a curved tube or curved tube connection. As shown, hydroblasting tip 170 includes a plurality of apertures 174 intended to deliver water uniformly throughout the tube interior. The hydroblasting tips 170 are in fluid communication with flexible hose 160, which are themselves in fluid communication with the lances 126.

Due to the weight and size of heat exchanger tube bundles, it is necessary to clean the tube bundles on site. Accordingly, it is necessary to transport the present invention to a job site for operations. The present invention including rigid lance assembly 100, spool assembly 200 and positioning assembly 300 may be transported to the job site by any suitable means. It is contemplated that the present invention will be transported to a job site on a trailer as disclosed in U.S. patent application No. 489,001. Further, while the present invention may be used in conjunction with any high pressure, high volume fluid source, it is contemplated that the present invention will be used in conjunction with the invention disclosed and claimed in U.S. patent application No. 489,001.

Upon arriving at the job site, the positioner assembly 300 is removed from the trailer by means of a crane assembly as disclosed in U.S. patent application No. 489,001 and positioned normal to the end of a tube bundle "B" to be cleaned. The remote control pendant 30 is removed from its transport vehicle and positioned to permit the operator to observe lancing operations while maintaining a safe distance from the high pressure lances. Flexible hydraulic lines are used to connect the hydraulic motors 342 to a suitable hydraulic pressure source. The motors 342 are then activated to lower guide frame 330. The lance housing 100 and spool housing 200 are then mounted on carriage beam 362 utilizing a suitable lifting and placement means, such as the crane disclosed in U.S. patent application No. 489,001 or any other suitable means. The lance and spool assemblies 100 and 200 are then secured to the carriage beam 362. The operator inspects the tube bundle spacing and selects the forward guide plate 176A/B which best corresponds with tube bundle size and spacing. The forward guide plate 176A/B is inserted around guide tubes 156.

A flexible hydraulic hose (not shown) is used to interconnect the spool hydraulic drive motor 234 with a suitable hydraulic pressure source. The spool assembly 200 is in communication with a high pressure water source by means of a hose H which is connected to union 230. The lances 126 and hoses 160 are thus in fluid communication with the high pressure water source through hose 218 and manifold 108. As used herein, it should be understood that lances 126 are rigid and therefore may be referred to as rigid lances from time to time, and that hoses 160 are flexible and therefore may be referred to a flexible lances 158 from time to time.

The lance and spool assemblies 100 and 200 are then positioned with respect to the tube bundle tubes by the selective application of hydraulic pressure to motors 342. Hydraulic pressure to spool drive motor 234 feeds out hose 218 and advances manifold 108 which in turn advances rigid/flexible lances 126/158. The rigid/flexible lances 126/158 advance out of the housing 102, through the first guide plate 152 and into the guide tubes 136. The flexible lances 160 are thus indexed to the proper centerlines for individual tubes within tube bundle "B" when the flexible lances 160 exit forward guide plate 176A/B and enter tube bundle "B." The high pressure water source is activated by the operator causing the high pressure water to flow through hose H, hose 218, into manifold 108 and out rigid/flexible lances 126/158 into the individual tubes. The flexible lances 158 continue to advance into the tubes, cleaning deposits away from the inside. Should one of the lances encounter an obstruction it is unable to clean away, the excess water pressure will be channeled into the remaining rigid/flexible lances 126/158 through manifold 108 counterbore 116. Further, a commercial needle valve (not shown) may be placed in the hydraulic line powering hydraulic motor 234 to limit hydraulic pressure. When a lance encounters an obstruction, if the water pressure or the forward motion of the lance does not dislodge the obstruction, the needle valve will prevent the motor 234 hydraulic pressure from increasing. By limiting the pressure, the present invention prevents the rigid/flexible lances 126/158 from buckling when attempting to clear the obstruction.

As shown in FIG. 18, heat exchanger tubes which follow a curved path may be cleaned by the present invention utilizing the flexible lance indexing assembly 150. Rigid lances 126 ar advanced in the manner described above. As rigid lances 126 are advanced, flexible lances 158 are advanced out of guide tubes 156 into the tubes in heat exchanger bundle B. As the hose 160 is flexible, the flexible lances 158 may be advanced by the rigid lances 126 to traverse a curved path. Thus, the present invention is capable of cleaning the interior of heat exchanger tubes following a curved path, including tube inter-connections.

The present invention, when used in conjunction with a suitable means for supporting and rotating the tube bundle "B," such as that disclosed in U.S. patent application No. 489,001, is thus capable of cleaning the interior of all tubes within a tube bundle by positioning the lances vertically and horizontally. Further, a single operator is capable of positioning the rigid lance and spool assemblies 100 and 200 and controlling the water flow from remote control pendant 30. Thus a single operator is capable of carrying out multi-lance cleaning operations.

Further, the present invention may be used independent of the positioning and support assembly 300. FIG. 19 is a perspective view showing the lance and spool assemblies 100 and 200 lifted and positioned by a vertical crane C. It is contemplated that other suitable mechanical means may be use to lift and position the lance and spool assemblies 100 and 200 to permit the lances 126 (not shown) to advance vertically into tube bundle B. Thus, lance and spool assemblies 100 and 200 may be used to clean tube bundles which, for reasons of size or weight must be cleaned in a vertical position.

The description given herein is intended to illustrate the preferred and alternate embodiments of the present invention. It is possible for one skilled in the art to make various changes to the details of the apparatus without departing from the spirit of this invention. Therefore, it is intended that all such variations be included within the scope of the present invention as claimed.