Auto-indexing lance positioner apparatus and system

A system and an apparatus for positioning a plurality of flexible cleaning lances includes a frame removably fastened parallel a tube sheet of a heat exchanger. The apparatus includes a smart lance tractor drive for advancing and retracting one or more lance hoses through one or more lance guide tubes into tubes penetrating through the heat exchanger tube sheet, a controller, one or more AC induction sensors on the tubes operable to sense holes in the tube sheet, and a tumble box connected to the controller operable to generate electrical power to the AC induction sensor from an air pressure source, supply electrical power to the controller and distribute pneumatic power to pneumatic motors for positioning the tractor drive on the positioner frame. The tractor drive includes sensors for detection of mismatch between expected and actual lance positions and automated drive reversal operation to remove blockages within tubes being cleaned.

BACKGROUND OF THE DISCLOSURE

The present disclosure is directed to high pressure waterblasting lance positioning systems. Embodiments of the present disclosure are directed to an apparatus and a system for aligning one or more flexible tube cleaning lances in registry with tube openings through a heat exchanger tube sheet.

One auto-indexing system is described in US Patent Publication No. 20170307312 by Wall et. al. This system includes optical scanning, cleaning and inspecting tubes of a tube bundle in a heat exchanger. It involves use of a laser or LED optical scanner for scanning the surface of the tube sheet to locate the holes or locate holes from a predetermined map. Once the hole location is determined, the cleaner is positioned over the hole and the tube cleaned.

Another apparatus for a tube sheet indexer is disclosed in US Patent Publication 20170356702. This indexer utilizes a pre-learned hole pattern to identify location of subsequent holes once a particular hole location is sensed. This is because tube sheet hole penetrations are typically spaced apart at known locations from each other in either or both an x direction or y location. However, in some circumstances a hole location may be plugged or capped. Hence not always are the hole locations accurate or precise for accurate positioning of a flexible lance drive. Furthermore, an interference sensor must be used in addition to displacement sensors in order to ascertain accurate hole locations.

In some cases a camera may be utilized to optically learn and map the tube sheet faceplate arrangement in advance. However, such optical sensors require an unobstructed view of the tube sheet face and therefore cannot be utilized while the apparatus is in use. Further, optical sensors are very sensitive to light and shadows which can significantly affect the reliability of such scanning in adverse lighting conditions. The tube sheet face may also be caked with built up carbon, bitumen or other materials and therefore must be cleansed of such substances prior to use of optical sensors. Hence the tube sheet must first be cleaned of debris and the mapping must be done prior to tube cleaning operations. What is needed, therefore, is a system that can accurately sense and position a flexible lance drive apparatus in registry with each of a plurality of unplugged tube sheet holes without need of camera or an optical sensor for hole location and without resort to referencing to a predetermined map.

Conventional high pressure waterblasting equipment and systems also require an operator to activate high pressure fluid dump valves to divert high pressure fluid safely in the event of an equipment malfunction. Such systems often include a “deadman” switch or foot operated lever that must be actuated to stop the high pressure pump and/or dump/divert high pressure fluid to atmosphere or to a suitable container. These switches typically must be continuously depressed or held in order to permit high pressure fluid to be directed through the lance hose to the object being cleaned. When an event occurs requiring diversion or dump of high pressure fluid, it may take a second or two for the operator to react and release such a switch. Furthermore, it takes a finite amount of time for high pressure fluid pressure to decrease to atmospheric pressure. During such reaction and decay time, the high pressure fluid may still cause damage in the event of an unexpected malfunction. Therefore, there is a need for a smart system that can sense such events and dump or divert high pressure fluid pressure quickly in order to reduce these delays as much as possible.

SUMMARY OF THE DISCLOSURE

The present disclosure directly addresses such needs. The embodiments described herein may be utilized with rigid (fixed) lances or flexible lances and lance hoses. One embodiment of a lance indexing drive positioning system in accordance with the present disclosure utilizes an AC (alternating current) pulse inductive coupling sensor array mounted at a distal end of a flexible lance guide tube fastened to the lance tractor drive apparatus. This type of inductive sensor is insensitive to fouling, dirt, or other debris or detritus that may be present on a heat exchanger tube sheet face, thus eliminating the need for preliminary cleaning of the heat exchanger tube sheet prior to installation of the system.

When the lance tractor drive is mounted on a lance positioner frame fastened to a heat exchanger tube sheet face, for example, the lance guide tube or tubes are aligned perpendicular to the plane of the tube sheet face. The distal end(s) of the guide tube(s) are spaced from the tube sheet face by a gap, which is preferably less than an inch, to minimize the range of unconfined water spray during cleaning operations.

The pulse induction sensor array is configured with a single transmit coil placed at the distal end of one or more of the lance guide tubes and a plurality of receive coils arranged around and within the vicinity of each transmit coil. An AC pulse through the transmit coil generates an AC magnetic field that, when it collapses, causes eddy currents to be formed in any conductive material in the volume of the produced magnetic field. These eddy currents cause a magnetic field of a reverse polarity to be generated which creates a voltage differential in the receive coils. The transmit coils are larger than the receive coils so as to create eddy currents in poorly conductive materials in a volume that is proportional to the size of the guide tube to which the transmit coil is mounted. The receive coils are much smaller in diameter and are spaced around the periphery of the transmit coil. In an exemplary embodiment of the present disclosure the transmit coil is positioned on and around the distal end of the guide tube and hence adjacent the gap between the guide tube and the face of the tube sheet. The receive coils are spaced apart and positioned to form a ring of coils around the distal end of the guide tube. The eddy currents sensed by the receive coils are amplified and processed in a comparator in order to detect the presence or absence of metallic material adjacent the receive coils hence the signal is used to determine tube location.

Embodiments of the system in accordance with the present disclosure also sense and track position of a flexible lance hose being fed through the lance tractor drive apparatus. In one exemplary embodiment, hose position encoders/sensors are located in the inlet hose stop block fastened to the hose inlet of the lance tractor drive apparatus. The position sensors may be wheels that engage the lance hose as it is fed through the tractor drive apparatus. Each wheel rotation causes a signal to be sent to a controller indicative of the distance traveled by the hose during that wheel rotation. Another set of encoders also sense hose stop clips or clamps, also known as “footballs”, which are fastened to the high pressure lance hose, that signal the desired end of lance hose travel.

Such a lance tractor drive apparatus as described herein is essentially a smart tractor that, as part of the overall system, can provide a number of pieces of information to a data collection processor for subsequent analysis and utilization. For example one embodiment of a lance tractor drive apparatus described herein and its controller can provide current status, track machine operational status, as well as current status of the tubes being cleaned and can be used to predict status of each and every tube being cleaned. This data can be utilized to determine long term conditions of a heat exchanger, frequency of cleaning operations needed to optimize operation, and provide different job statistics that can be utilized to improve efficiencies, etc.

An exemplary embodiment in accordance with the present disclosure may alternatively be viewed as including a flexible high pressure fluid cleaning lance drive apparatus that includes a housing, at least one drive motor having a drive axle in the housing carrying a cylindrical spline drive roller, and a plurality of cylindrical guide rollers on fixed axles aligned parallel to the spline drive roller. A side surface of each guide roller and the at least one spline drive roller is tangent to a common plane between the rollers. An endless belt is wrapped around the at least one spline drive roller and the guide rollers. The belt has a transverse splined inner surface having splines shaped complementary to splines on the spline drive roller.

The drive apparatus further has a bias member supporting a plurality of follower rollers each aligned above one of the at least one spline drive roller and guide rollers, wherein the bias member is operable to press each follower roller toward one of the spline drive rollers and guide rollers to frictionally grip a flexible lance hose when sandwiched between the follower rollers and the endless belt. The apparatus includes a first sensor coupled to the drive roller for sensing position of the endless belt, a second sensor coupled to a first one of the follower rollers for sensing position of the first follower roller relative to a first flexible lance hose sandwiched between the first follower roller and the endless belt, and at least a first comparator coupled to the first and second sensors operable to determine a first mismatch between the first follower roller position and the endless belt position.

This embodiment of an apparatus in accordance with the present disclosure preferably further includes a third sensor coupled to a second one of the follower rollers for sensing position of the second one of the follower rollers relative to a second flexible lance hose sandwiched between the second one of the follower rollers and the endless belt. The exemplary apparatus also may include a second comparator operable to compare the second follower roller position to the endless belt position and determine a second mismatch between the second follower roller position and the endless belt position.

Preferably a controller is coupled to the first comparator and the second comparator operable to initiate an autostroke sequence of operations upon the first mismatch and second mismatch differing by a predetermined threshold. A fourth sensor may be coupled to a third one of the follower rollers for sensing position of the third one of the follower rollers relative to a third flexible lance hose sandwiched between the third one of the follower rollers and the endless belt. Also, a third comparator may be provided operable to compare the third follower roller position to the endless belt position and determine a third mismatch between the third follower roller position and the endless belt position. The controller is preferably coupled to the first comparator, the second comparator and the third comparator and is operable to initiate an autostroke sequence of operations upon any one of the first, second and third mismatches exceeding a predetermined threshold. Furthermore, the controller is preferably operable to modify clamping force if more than one of the first, second and third mismatches exceed a different predetermined threshold. The sensors utilized herein may be magnetic or Hall effect sensors and preferably include quadrature encoder sensors.

A flexible high pressure fluid cleaning lance drive apparatus in accordance with the present disclosure may comprise a housing, at least one drive motor having a drive axle in the housing carrying a cylindrical spline drive roller, a plurality of cylindrical guide rollers on fixed axles aligned parallel to the spline drive roller, and wherein a side surface of each guide roller and the at least one spline drive roller is tangent to a common plane between the rollers, an endless belt wrapped around the at least one spline drive roller and the guide rollers, the belt having a transverse splined inner surface having splines shaped complementary to splines on the spline drive roller, a bias member supporting a plurality of follower rollers each aligned above one of the at least one spline drive roller and guide rollers, wherein the bias member is operable to press each follower roller toward one of the spline drive rollers and guide rollers to frictionally grip a flexible lance hose when sandwiched between the follower rollers and the endless belt.

The apparatus includes a first sensor coupled to the drive roller for sensing endless belt position and a plurality of second sensors each coupled to one of the plurality of follower rollers each for sensing position of the one of the follower rollers relative to a flexible lance hose sandwiched between the one of the follower rollers and the endless belt. The apparatus preferably includes a first comparator coupled to the first sensor and each second sensor operable to determine a mismatch between each follower roller position and the endless belt position. The apparatus may further include a second comparator operable to compare each of the plurality of flexible lance hose positions with each other to determine another mismatch therebetween and a controller coupled to the second comparator operable to initiate an autostroke sequence of operations upon the another mismatch exceeding a predetermined threshold.

An apparatus in accordance with the present disclosure may alternatively be viewed as including a housing, at least one drive motor having a drive axle in the housing carrying a cylindrical drive roller, a plurality of cylindrical guide rollers on fixed axles aligned parallel to the drive roller, and wherein a side surface of each guide roller and the at least one drive roller is tangent to a common plane between the rollers, an endless belt wrapped around the at least one drive roller and the guide rollers, a bias member supporting a plurality of follower rollers each aligned above one of the at least one drive roller and guide rollers, wherein the bias member is operable to press each follower roller toward one of the drive rollers and guide rollers to frictionally grip a flexible lance hose when sandwiched between the follower rollers and the endless belt, a first sensor such as a magnetic quadrature encoder sensor coupled to the drive roller for sensing endless belt position, a plurality of second sensors such as magnetic quadrature encoder sensors each coupled to one of the plurality of follower rollers each for sensing position of the one of the follower rollers relative to a flexible lance hose sandwiched between the one of the follower rollers and the endless belt, a first comparator coupled to the first sensor and each second sensor operable to determine a mismatch between each follower roller position and the endless belt position, and a second comparator coupled to each of the second sensors operable to determine a mismatch between any two of the follower roller positions. The apparatus may also preferably include a controller coupled to the second comparator operable to initiate an autostroke sequence of operations upon the mismatch exceeding a predetermined threshold and may further include the controller being operable to initiate a change of clamp force or pressure if the mismatch between the follower roller positions and the belt position all or at least more than one, exceed a predetermined threshold.

An apparatus for cleaning tubes in a heat exchanger in accordance with the present disclosure may alternatively be viewed as including a lance positioner frame configured to be fastened to a heat exchanger tube sheet and a flexible lance drive fastenable to the frame configured for guiding a flexible cleaning lance from the lance drive into a tube penetrating through the tube sheet. The lance drive preferably has a follower roller riding on the flexible cleaning lance. This follower roller includes a sensor, such as a magnetic quadrature encoder that operates to provide roller position and direction of movement information for the flexible cleaning lance. The apparatus also includes a control box communicating with motors on the positioner frame and motors in the lance drive for controlling operation of the lance drive, a tumble box for converting air pressure to electrical power and for manipulating valves including a dump valve preferably contained within the tumble box for maintaining cleaning fluid pressure to the flexible cleaning lance when energized, wherein the electrical power is provided to components within the control box, the dump valve and the flexible lance drive, and a controller coupled to the follower roller sensor for sensing flexible lance position and sensing a reversal of flexible lance movement direction. This controller is operable to send a signal to the tumble box to actuate the dump valve to divert fluid pressure to atmosphere upon sensing the reversal of flexible lance hose direction.

Further features, advantages and characteristics of the embodiments of this disclosure will be apparent from reading the following detailed description when taken in conjunction with the drawing figures.

DETAILED DESCRIPTION

FIG. 1is a diagram of the major components of one autoindexing lance positioning apparatus in accordance with an exemplary embodiment of the present disclosure. The autoindexing lance positioning apparatus100includes a lance hose tractor drive102, an x-y drive positioner frame104, a flexible lance guide tube assembly106, an electrical controller or control box108and an air-electric interface box known as a “tumble box”110connected together as described below. The lance hose tractor drive102is fastened to a vertical positioner rail112of the x-y positioner frame104. This x-y positioner frame104has an air motor114that horizontally moves the vertical positioner rail112on a horizontal upper rail116. The x-y positioner frame104also includes another air motor118that moves a carrier, or trolley119mounted on the vertical rail112of the x-y positioner frame104. This trolley119supports the drive102and a guide assembly106for movement vertically on the rail112.

The lance hose drive102and the guide assembly106are separately shown inFIG. 3. The lance hose drive102may be configured to drive any number of flexible lances101, each comprising a lance hose167coupled to a nozzle105. The drive102may be a one, two, or three lance drive such as a ProDrive, an ABX2L or ABX3L available from StoneAge Inc. One example, an ABX3L, is described and shown here. The guide assembly106includes, in this exemplary embodiment100, a set of three guide tubes122adjustably fastened to a bracket120fastened to the trolley119along with a sensor amplifier block124beneath the tubes122and fastened to the bracket120. The tractor drive102is fastened to the bracket120via a hose stop collet or crimp encoder block126fastened to a rear end of the set of three guide tubes122.

Each of the guide tubes122is an elongated cylindrical tube, preferably made of a metal, such as stainless steel, aluminum, brass, a durable plastic, or other rigid material with a high electrical resistivity. An AC pulse sensor150in accordance with the present disclosure is mounted at the distal end of each guide tube122. An enlarged distal end of the tractor drive102and guide assembly106is shown inFIG. 4, showing the component arrangement of the AC pulse sensor150. The distal end123of each tube122is fitted with a radial flange128having set of eight cup shaped receive coil locating cups130formed therein and arranged around the flange128with four cups130at cardinal positions (N, S, E, W) and four equidistantly spaced intermediate positions, thus each being 45 degrees displaced from each other around the distal end123of the tube122. For a tube inside diameter of 1 inch, for example, the inside diameter of each of the cups130is about 0.25 inch or smaller.

Each of the cups130carries therein a receive coil132. Alternatively, the receive coils132may each be wrapped around a locating pin on the flange128rather than being disposed in a cup130as shown. A transmit coil134is wound around the distal end of each tube122and adjacent the receive coil cups130such that the transmit coil134and receive coils132are closely coupled. One embodiment of each guide tube122may have a ceramic portion that interfaces with the metal of the guide tube122toward the distal end of the guide tube. This non-interfering ceramic portion distances the transmit coil134from the metal of the guide tube122.

A simplified drawing of the coil arrangement is shown inFIG. 5. A 400 Hz AC pulse injected sensor array based around a single transmit coil134and multiple receive coils132is used in this exemplary embodiment. The transmit coil134is fed with an AC current pulse such that it generates a magnetic field136around it (shown inFIG. 6F). When this pulse is removed, the magnetic field136collapses. When field136collapses, eddy currents are formed in any conductive material in the volume of the produced magnetic field136. These eddy currents cause a magnetic field of a reverse polarity to be generated in the receive coils which creates a voltage differential therein, generating a current, which is sent via wire to the sensor amplifier block124. The transmit coils134are large so as to create eddy currents in poorly conductive materials in a volume that is proportional to the size of the guide tube122. The receive coils132are much smaller than the transmit coil and are placed so as to detect only the eddy currents directly in front of them. The circular array of receive coils thereby creates a magnetic flux density image based on the array arrangement of receive coils132.

The receive coils132are placed in specific balancing zones of the transmit coil's magnetic field. These zones are selected such that no induced voltage is generated in the receive coils132if no other conductive material or magnetic fields are in the proximity of the sensor head150. The coils132can be tilted to increase sensitivity to eddy currents in specific locations of the sensed volume as shown inFIG. 5. In the left view, the receive coils132are arranged parallel to the axis of the transmit coil. In the middle view inFIG. 5, the receive coils are arranged tilted inward toward the axis through the transmit coil134. This arrangement increases center resolution of the receive coil array. This allows the sensor array to be able to detect with resolution what is in front of the tube122at the end123of the guide tube122as well as baffles and obstructions perpendicular to the face of the transmit coil134. The right view inFIG. 5shows the receive coils tilted out away from the centerline of the transmit coil. In this arrangement, the receive coils132are tilted off the plane of the transmit coil. This increases resolution in areas not directly in front of the transmit coil134.

An exemplary embodiment of one receive coil132arrangement is illustrated inFIG. 6A. Eight receive coils132are positioned around the end of the guide tube122. As described above, the receive coils may be disposed within cups130, as shown inFIG. 6A, or each may be wrapped around a locating pin on the flange128.

In an alternative embodiment, the receive coils132may be printed on one or more printed circuit boards (PCBs)152. The PCBs152containing the receive coils132are attached to the distal end of the guide tube122adjacent the transmit coil134. The use of PCBs152allows for a variety of receive coil132shapes and lengths to be manufactured. The PCB152also provides mechanical stability to the potentially fragile receive coils132.

Various exemplary embodiments of receive coils132on PCBs152are shown inFIGS. 6B-6E.FIG. 6Billustrates four receive coils132each configured in an essentially flat spiral shape.FIG. 6Cillustrates four receive coils132printed as curved lines.FIG. 6Dillustrates four receive coils132each printed in a plane to form zig-zag lines with an overall trapezoidal shape.FIG. 6Eillustrates four receive coils132each printed in a plane as zig-zag lines to form an overall rectangular shape. The receive coils132may also be printed in multiple layers within the PCB and can be printed in many additional shapes, and any number of receive coils132may be used. Preferably each receive coil132has a corresponding opposite receive coil132located across the from it on the PCB152(e.g. North-South and East-West positions). In preferred embodiments, four or eight receive coils132are used on a PCB mounted in a plane around the distal end of each guide tube122.

The magnetic field136generated by the transmit coils134wrapped around the distal end of the tube122is illustrated inFIG. 6F. The eddy currents formed in the receive coils132by the lines of flux generated by the single transmit coil134are conducted by a pair of wires (not shown) through a protective channel or sleeve138alongside and fastened to an underside of the tube122to an analog signal processor circuit within the sensor amplifier block124mounted on the bracket120beneath the tubes122. Preferably the type of object sensed by the sensor array150is identified and categorized by the analog signal processor circuit within the amplifier block124, and thence sent to the electric control box108for subsequent signal processing and use as described more fully below with reference toFIG. 2and the process flow diagrams ofFIGS. 11-18.

Referring now toFIG. 7, an enlarged view of the rear end of the guide assembly106and front end of the tractor drive102is shown with the internal components of the hose stop or crimp collet block126visible. The collet block126includes three transducers140that each sense the presence of a hose clamp or crimp (not shown) fastened to a lance hose (not shown) adjacent its nozzle. This hose crimp is clamped tightly to the lance hose near the distal end of the lance hose and physically interferes with hose passage through the collet opening within the collet block126so as to prevent withdrawal of the high pressure hose back through the drive102. These crimps and closely sized collets in the collet block126act as a safety measure to prevent inadvertent withdrawal of the lance hose.

The transducers140preferably magnetically sense presence of a crimp and send a control signal therefore to control circuitry for the lance drive102to de-energize the “retract” lance drive motors when a crimp is sensed. In addition, the transducer140signal indicates full withdrawal of a lance hose and therefore its signal can be used to zero out hose position of the lance hose as determined by the hose travel transducers further described below. Furthermore, in these multi-lance systems, these transducers140may be used together to synchronize lance position. The lance tractor drive102may be driven until all lance footballs (indicating full lance insertion) or crimps (indicating full lance withdraw from the heat exchanger) are detected.

Turning now toFIG. 8, a rear perspective view of the lance hose drive102is shown with the outer surface transparent and internal components of the rear collet block assembly160visible. In the embodiment of the hose drive102shown, there are three stop collet football transducers162located in this rear collet block assembly160. Each of these transducers162sense the presence of a hose stop football, again a C shaped fitting fastened tightly to a lance hose and positioned on the hose to indicate maximum travel of the lance hose through the drive102when the stop football abuts against or is in close proximity to the transducer162. Each of these transducers162preferably includes a magnetic switch operable to close when the football contacts the transducer162. This switch then sends a signal to control circuitry that can be utilized to de-energize the lance drive102and or automatically reverse the lance drive102as may be needed. The rear stop collet assembly160also has three hose travel transducer sets. In this exemplary embodiment these transducers are friction wheel sensors164for indicating incremental passage of a lance hose through the collet assembly160.

FIG. 9is a separate enlarged view of one of these friction wheel sensors164. Each sensor164includes a friction wheel166that engages a lance hose167and rolls along the hose167as it is fed into, through and out of the lance drive102and through one of the guide tubes122. This wheel166has a pair of transducers168and170that count angular rotation of the wheel166and hence are representative of the distance of hose travel into and out of the drive102. These transducers168and170send signals proportional to hose drive distance traveled to the electrical control box108for further processing. The sensors164may be Hall effect sensors and the wheel166may be outfitted with a plurality of magnets such that rotation of the wheel166with passage of the magnets by the sensor164generates a current signal which is converted to a hose distance travel. The hose travel distance determined thereby is transmitted to the control box108. In this manner, the tractor drive102is a smart tractor, providing distance traveled information for each lance. Furthermore, the transducers140in concert with the sensors164can be used to repetitively count and track lance insertions. This lance position information may also be utilized in conjunction with expected lance travel information determined from a sensor located on the lance drive motor to automatically apply lance reversals, called “autostroke” to “peck” away at internal tube obstructions. Such autostroke functionality is disclosed in greater detail below with reference toFIGS. 35-43.

All of the components that are mounted on the positioner frame104including the air motors,114,116, the sensor head150and guide assembly106, and the lance hose drive tractor102may be subjected to environmental conditions which could include flammable gases as well as copious amounts of water. Hence any electrical currents present in the various sensors must be minimized and must be in an air and water tight containment.

Electrical power may not be readily available at a location where the apparatus of this disclosure is needed. Compressed air is much more available many in industrial settings and is acceptable to users. Compressed air is also intrinsically safe to use. It is therefore a part of the design of the present apparatus100in accordance with the present disclosure that a tumble box110be included, which provides a pneumatic electrical generator to supply needed electrical voltage to components typically at no more than 12V. Thus the only external power required by the apparatus100in accordance with the present disclosure is a supply of 100 psi air pressure. All electrical wiring and circuitry is hermetically sealed or contained in waterproof and airtight sealed housings.

The tumble box110takes pneumatic pressure and converts it to electrical power for all the sensors, and electrical controls of the apparatus100. The tumble box110includes a sealed pneumatic to electrical power generator as well as all the operational air control valves for selectively supplying air pressure to air motors114,118, and to the forward and reverse air motors within the tractor drive102, as well as emergency high pressure water dump valve control and other pneumatic functions.

The tumble box110also self generates electrical power for the control circuitry located in the electric control box108for overall operation of the apparatus100and automated process software. The tumble box110and electric control box108are typically located out away from the area of high pressure, such as 20-40 feet from the components102,104and106. For example, the tumble box110may be 5-25 feet from the X-Y positioner frame104and the control box108another 5-25 feet from the tumble box110. Furthermore, this arrangement permits an operator to optionally utilize a remote control console such as a joystick control board or panel that communicates with the electric control box108via a wireless signal such as a Bluetooth signal, for example, permitting the operator to even further remove himself or herself from the vicinity of the heat exchange tube sheet area.

Referring back now toFIG. 2, a simplified electrical schematic of the apparatus100is shown. The lance drive tractor102carries front collet block126which includes three hose stop or crimp encoders140. The tractor102also carries the rear encoder block160which has three hose stop encoders162along with lance hose position sensors166and168for tracking the distance traveled by the lances as they are driven by the tractor102into and out of tubes being cleaned. The tractor drive102also feeds the sensor head150position signals from the sensor amplifier block124through the tumble box110to the control box108.

The electric control box108signals and controls the air valves in the tumble box110to provide pneumatic power to the vertical drive air motor118and horizontal drive motor114. In turn, each of these pneumatic drive motors114and118has a pair of position encoders that feed through the tumble box110to the control circuitry in the control box108to provide x and y coordinate position data to the control circuitry. Each of the sensor amplifier block124, the front hose stop collet block126and rear hose stop block160, the tumble box110and the x-y positioner drives114and118has an internal master control unit (MCU) for processing signals needed to communicate position information to the software resident in the control box108. Furthermore, the control box108contains a database and memory for a position monitor/map of the tube sheet to which the apparatus100is attached.

FIG. 10shows a plan view of an exemplary tube sheet200, with an array of tube penetrations or holes202indicated by clear circles. Initially the apparatus100is positioned via the x-y positioner frame104over an approximately central position on the tube sheet200with the sensors150spaced from the face of the tube sheet200by a distance less than about 1 inch, preferably about 0.5 inch. As the apparatus100moves the lance drive102over the surface of the tube sheet200, the sensors150operate to sense one of four defined types of objects. A hole202is defined as a gap in the measured surface corresponding to a tube which needs to be cleaned. An exemplary obstacle206is a protrusion from the surface that needs to be avoided. A plug204is an anomaly in the composition of the surface which must be passed over. An edge208is the point on the surface beyond which further measurement need not be taken. Typically this means the outer margin or edge of the tube sheet200.

The detection system utilizing sensors150traverses the tube sheet200until an “event” is detected by an abrupt change in eddy current sensed by the receive coils132. Then an algorithm determines whether the event detected is an object and categorizes it as a hole, an obstacle, a plug or an edge, or undefined. This detection system utilizes two pairs of receive coil sensors132, each aligned on the x and y axis respectively of the tube sheet200. Thus an Rx N and Rx S receive coils132are analyzed as the Rx Y axis pair. An Rx E and Rx W receive coils132are analyzed as the Rx X axis pair. The Rx X and Rx Y pairs send a signal to the sensor amplifier and processor. When the signal processed indicates the presence of an object event by either of the pairs, the event is categorized as one of a Hole, Plug, Edge, or Obstacle or Undefined (like an obstacle, i.e. to be avoided).

This identification and classification is similar for the intermediate sensors132. Thus, the Rx NW and Rx SE sensor coils are analyzed as the Rx NW pair. The Rx NE and Rx SW sensor coils are analyzed as the Rx NE pair. Whenever an event is indicated, the coordinates of the event location queried to ascertain the object, and the coordinates are then stored in a digital Position Map for later use.

This analysis may include comparing the waveform of the sensor pair to identify the waveform as representative of one of the four types of objects defined above. For example, if the waveform represents a hole, the position monitor is appropriately updated. If the waveform is identified as an obstacle, a further inquiry is made whether the obstacle is of a known type and, if so, categorized accordingly. On the other hand, if the waveform is of unknown type, the user is prompted to identify, such as raised edge, raised plug, barrier, etc. and the position monitor map updated accordingly.

InFIG. 10, a plan view of an exemplary tube sheet200is shown. A Plug204is shown as a black circle. An obstacle206is shown as a square. An edge208is shown as the perimeter of the tube sheet200. The pitch of the tube spacing is the horizontal distance between adjacent tubes. The height “h” is the vertical separation of the rows of holes202. This information is detected, stored and built up in the Position Map database “on the fly” through the processes described below with reference toFIGS. 11 through 19.

FIG. 11is a process diagram showing the user input required to begin the autoindexing process utilizing the apparatus100.

The program begins in operation170where the user turns the system on. Control transfers to Display message block172which shows the user the instruction to position the guide tube assembly in a central location over the tube sheet200and centered over a hole202(or series of 3 holes) and press enter. Control then transfers to Start operation174. The user is then asked to confirm the lances are fully retracted in operation176. If the lances are fully retracted their position will be sensed by the transducers140sensing the footballs of all three lances indicating full retraction of the lance hoses. If so, query is then asked of the user in operation178whether to proceed. If so, in operation180, the Position Map is then initialized with the apparatus100given or set at the present location and this location is initialized as location c (0,0). Control then passes to The Initial Hole Jog sequence210shown inFIG. 12. Then the overall process proceeds to the Clean Tubes sequence300shown inFIG. 15.

The overall High Level operation sequence shown inFIG. 14includes, in sequence, establishing Initial position sequence180, Clean tubes sequence300, and Find Tubes sequence400.FIG. 14also illustrates the content of the Position Monitor database.

Referring now toFIG. 12, the initial jog sequence210begins in operation212. Control then invokes the Identify Object sequence500. This sequence is performed until control returns to operation212. Control then passes to operation214which queries the position Monitor for objects. Assuming no object is found at the starting position (0,0), control then transfers to concurrent-move left and up operation216. This operation216directs a jog left and up command sent to air motors114and118to incrementally move the lance drive102a predetermined distance in the −x and +y direction. Control then transfers to operation218, in which the Position Monitor database is again queried for whether a Hole or an Obstacle is identified in the database based on the new position of the lance drive102. If a hole is identified, control transfers to operation220where the position monitor database is updated. On the other hand, if in operation218the object is an obstacle, control transfers to the user via a prompt222to move around the obstacle. Upon completion of the move around obstacle the Position Monitor database is again queried in operation224whether the new position is a hole or an obstacle. If a hole, control passes to operation220. If not, it is an obstacle and control passes back to the manual jog around obstacle operation222. Once the position monitor database is updated in operation220, control passes through the Identify object sequence500to an end operation226. At this point an initial hole has been identified. Control then passes to the Clean Tubes sequence shown inFIG. 15.

The Clean Tubes sequence300begins in operation302where the lance drive100feeds three lances into the tubes to be cleaned until the hose stops are detected by the rear football transducers162. Control then transfers to query operation303which asks whether all lances are through the tubes202such that all rear football transducers162indicate receipt of a football. If not, lance drive100continues to feed lances until all transducers162sense football presence. Control then transfers to operation304. In operation304, the lance drive100reverses direction and feeds the lances out. Control transfers to query operation306which asks whether all transducers140indicate the presence of a football or hose crimp. If so, control transfers to stop tractor operation308. If not, lance drive100continues to feed the lances out until all hose footballs are sensed by transducers140. Control then transfers to operation310where the position monitor is updated to indicate the tubes cleaned. Control then transfers to return or end operation312. Control then returns to the high level operations shown inFIG. 14.

Once the first set of 3 tubes are cleaned in sequence300, control transfers to Find Tubes sequence400shown inFIG. 16. Find Tubes sequence400begins with Jog Sequence600shown inFIG. 18. Jog Sequence600begins with an Identify Object sequence500shown inFIG. 13. If the Identify Object routine is not required, control moves to query operation602which asks the Position Monitor whether there are any unexplored directions (up, down, right, or left). Assuming the answer is yes, control transfers to query604which asks whether a move left is available. If yes, control transfers to operation606and a signal is sent to the air motor118to jog the drive102left.

If a move left operation is not available control transfers to query operation608which asks whether a move right is available. If yes, control transfers to operation610in which a signal is sent to the air motor118to jog the drive102right. If the answer in operation608is no, control transfers to query operation612which asks if a move up available. If yes, control transfers to operation614in which a signal is sent to the air motor114to jog the drive102up.

If the answer in query operation612is no, control transfers to query operation616which asks whether a move down is available. If the answer is yes, control transfers to operation618in which a signal is sent to the air motor114to jog the drive102down.

If the answer in query operation616is no, control transfers to operation620which logs that no moves are available. Control then transfers to query622which then asks the user whether the jog sequence operation is complete, and, if so, updates the position monitor log in process operation624. If the query622answer is no, control transfers to query operation626. The user has ultimate control such that if system cannot find tubes, and the user confirms that there are none then the auto-indexing operations stop, reverting to manual control.

Once a jog operation is complete in one of operations606,610,614or618, control transfers to a query process operation628,630,632or634respectively where, in each case, the Position Monitor database is queried whether the location just jogged to is either a previously identified hole or whether the location is an obstacle. If the answer is an obstacle, control transfers to query operation626. If the answer is a hole, control transfers to operation624where the position monitor database is updated. Control then transfers from operation624to end the Identify Object process500.

In query operation626, the question is asked whether the location is a new or known obstacle. If the answer is a known obstacle, control transfers to query operation636which asks the position monitor whether the obstacle may be automatically jogged around. If yes, control transfers to auto-jog operation638where either the air motor114or118is instructed to move a predetermined distance to move past the known area. Control then transfers to operation640where the position monitor is again queried for either a hole or obstacle identified at the new location. If the answer is a hole, control transfers to operation624. If the answer in operation640is an obstacle, control transfers back to query operation626. Once the position monitor is updated in operation624, control passes to the end Identify Object process500.

If the answer in query operation626is that the obstacle is new, control transfers to operation642where the user is prompted for a manual jog around the obstacle. When a manual Jog is completed, control transfers to operation644which queries the position monitor for that new position, whether the new position is a hole or obstacle. If the position monitor indicates a hole, control again passes to operation624where the position monitor is updated. If the position monitor indicates an obstacle, control passes back to query operation636.

The process500is shown inFIG. 13. This process500begins in operation502. Control then transfers to operation504where the analog output of the position sensors150is processed. Control then transfers to a wave form ID algorithm in operation506. This wave form ID algorithm analyzes the analog output to categorize the signal from the sensors150into one of two types, either a hole is indicated or an obstacle. Control then transfers to query operation508which asks what is the object type. If the output is determined to be a hole, control transfers to process operation510which in turn directs an update of the position monitor for the location coordinates in operation512. If the output waveform is determined to be an obstacle in operation508, control transfers to query operation514which asks whether the obstacle is new or known. If new, the control transfers to operation516where the user is prompted to identify the obstacle. Control transfers to operation518where the user examines the waveform signal to classify the waveform signal and selects from a predetermined list of obstacles such as either an Edge, a Raised Edge, a Plug, or a Raised Plug obstacle. In order to conform the results of the waveform processing, and aid in the learning of what signal results equate to what type of obstacle is experienced in each instance, the user then inputs the result and control passes to operation512where the position monitor database for the location coordinates is updated with the type of object, i.e. hole, Edge, Raised Edge, Plug or Raised Plug. Control then returns in End operation520to whatever process called the Identify Object process500.

On the other hand, if the answer in query operation514is that the obstacle type is classified as known on query514, control transfers to operation522where the obstacle type is recognized. Control then transfers to operation512where the position monitor database is updated with the recognized type. Control then passes to End operation520. Control then passes back to whatever process called the Identify Object process500.

When the initial set of three holes have been cleaned in process300, control transfers to Find Tubes process400, which is shown inFIG. 16. This process begins in operation600which invokes jog operational sequence600shown inFIG. 18and described above. Upon completion of Jog sequence600, control returns to query operation414which asks whether the number of available hoes located equals the number of lances. In the illustrated embodiment shown inFIGS. 1 through 10, this is three. If yes, control transfers to the Center on Holes process430. From there, control transfers to update the position monitor in operation432. Once the position monitor is updated, the process control returns to the calling control sequence. On the other hand, if the query operation404answer is no, control transfers to operation406to determine whether the position monitor database recognizes that a tube sheet edge208has been reached. If no, control returns to jog sequence600. If the answer in operation406is yes, an edge has been recognized, then control transfers to operation408where the position monitor database is queried whether all holes in the current row have been cleaned. If the answer in operation408is yes, then the position monitor is updated in operation410, and the process control ends, with control returning to whichever process called sequence400.

On the other hand, if the answer in operation408is no, not all the holes in the current row have been cleaned according to the position monitor database, control transfers to the Reverse Jog Row sequence750shown inFIG. 19. This Reverse Jog Row sequence750is needed to finish cleaning a row where there is an incomplete set of three holes available. The process sequence750begins in operation752which calls operation sequence Identify Object sequence500. When the Identify Object sequence500is completed, control transfers to operation754. Operation754queries the Position Monitor database for the coordinates of the last tube position cleaned and the direction of motion required. Control then transfers to operation756wherein either the air motor114or air motor118, or both, is instructed to move in the opposite direction to the move direction identified in operation754. Control then transfers to query operation758where the Position Monitor is asked whether that last position was or was not a Hole. If not a hole, control transfers back to operation756for another jog in the reverse direction to that determined in operation754. If in query operation756the position Monitor database indicates that the current position is a previously identified hole, control transfers to query operation760. Query operation760asks whether the now available holes equals the number of active lances. If the answer is yes, control transfers to operation762where the position Monitor database is updated. Control then passes back to the Identify Object process500and thence returns to operation sequence300and the set of holes available is cleaned. In this instance, one or two holes would be cleaned twice such that the entire row is now clean. Control then passes to the Find Tubes operational sequence400.

The Center on Holes sequence430is shown inFIG. 17. This sequence is invoked whenever a hole is initially located in the Jog Sequence600in order to precisely position the lance drive102and three hose guide tubes122directly over the tube set of 3. This sequence begins in operation432where the analog position input: N, S, E, W, receive coil signals are retrieved from the sensor amplifier block124. The pairs of signals are separated. The NorthSouth signal pair is then compared in query operation434. If the signals are equal, then control transfers to operation436. The EastWest signal pair signals are compared in operation438. If the signals from the EastWest pair are equal, control also passes to operation436. However, if the NorthSouth pair signals differ, operation transfers to operation440where a difference jog signal is sent to the air motor118to vertically move the positioner102by the difference between the two NorthSouth signals. Similarly, if the EastWest pair signals differ as determined in operation438, a difference jog signal is determined in operation442and is sent to the air motor114to adjust position by the difference between the signals. Control then reverts back to query operations438and434until the signals are equal. Control then transfers to operation436where each other pair of receive coil signals (NW/SE, NE/SW) are processed in a similar manner until adjustment is no longer needed, i.e. all are equal. Control then transfers to operation444where the position monitor database is updated with the precise coordinates for the identified hole. Control then reverts in end operation446to return to whatever process called the Center on Holes process430.

In the process flow diagram descriptions described above, an error sequence is not included. However, if a non-standard event is encountered, for instance, there are timeout defaults. If a football fell off or a sensor failed, the control system would stop driving after a predetermined time and notify the user of an error state for manual intervention. In the event of a position sensor failure, for example, the drive102would continue to drive for 5 more seconds and then stop, informing the user by indication display to correct the situation, for example, check for stuck hose, football damaged, or sensor failure.

FIGS. 20 through 27are electrical block diagrams of each of the major blocks of the apparatus100shown inFIGS. 1 and 2.FIG. 20is a block diagram of the control box108which includes a visual display such as an LCD802that is fed by a single board computer module, or SBC/SOM804. The exemplary control box108includes a dump trigger switch806, a soft stop switch808, a left joystick810, and a right joystick812for an operator to manipulate in order to provide input commands to control the apparatus100. This control box108may include a battery if wirelessly connected to the apparatus100or may include electrical power from the tumble box110generated by the air motor generator contained therein. The SBC/SOM804may incorporate the position monitor database operably described above. The display802may include a circular representation of the tube sheet200as shown inFIG. 10, which indicates plugs, obstacles and holes as they are identified during the auto-indexing process described above.

FIG. 21is an electrical block diagram of the tumble box110. The tumble box includes an air valve driver board820along with an air valve manifold that directs air pressure to the vertical drive motor114and horizontal drive motor118as well as air pressure to the reversible air motor in the tractor drive102and the air cylinder (not shown) that provides hose clamp pressure and hence a clamping force applied to the drive and follower rollers in the tractor drive102. The tumble box110also include an air motor generator (AMG)822that generates electrical power for use throughout the apparatus100. This AMG822preferably also supplies power to the rechargeable battery in the control box108when wired thereto. The Tumble box110also includes an Emergency stop switch824to divert pneumatic pressure in the event of an unanticipated event. The tumble box110also includes two pressure transducers826and828. Pressure transducer826monitors supply air pressure, typically 100 psi. Pressure transducer828monitors clamp pressure.

FIG. 22shows the electrical block diagram for the sensor head150and guide assembly106amplifier block124. The amplifier block124contains a sensor transmit coil driver830that produces a 4 kHz signal that is fed to each of the transmit coils134. The receive coils132each transmit coupled eddy current signals received from the transmit coils to a receive analog processor832which in turn provides input to the main computation unit module (MCU)834. This MCU834sends its output to the control SBC/SOM804in the control box108.

FIG. 23shows the electrical block diagram for the rear encoder block160. The signals from the position sensors164and reverse encoders162are fed to an encoder board836and thence through the tractor102and the tumble box110to the control box108.

FIG. 24shows the rear hose stop encoders160also feed an encoder board838prior to being sent to the encoder block836.

FIG. 25shows the electrical block diagram for the forward encoder block126which sends the signals from the hose stop encoders140through an encoder board840via the analog processor124to the control box108.

FIGS. 26 and 27provide position indication from vertical and horizontal drives114and118through encoder boards842and844through the rear encoder block836and thence to the control box108for use in recording and tracking the positions determined via tractor102position and hence hole positions on the X-Y frame104. These electrical distribution block diagramsFIGS. 20-27reflect merely exemplary electrical routings. It is to be understood that many other configurations may also be implemented.

In addition, many changes may be made to the apparatus described above. For example, electric stepper motors may be utilized instead of the air motors114and118and the air motors in the lance tractor drive102in an all electrical version of the apparatus100. The lance hoses (not shown) may be configured with coding such as RFID tags so that the position transducers or encoders162and friction wheel encoders166and168may be other than specifically as above described. In an all electrical design of the apparatus100, the tumble box110may be eliminated and/or the sensor amplifier block124may be relocated, miniaturized, or incorporated into the electrical control box108or the hose stop collet block126. The apparatus100may require less than three sensors150, or less than eight receive coils132in each sensor head150. Thus the above description is merely exemplary.

One exemplary embodiment of a controller box108is a handheld remote controller1000shown in perspective top and bottom views inFIGS. 28 and 29. This controller1000is designed to be held in both hands by an operator standing a safe distance remotely from the apparatus100. The controller1000has a left hand grip1002and a right hand grip1004sandwiching an LCD display screen1006therebetween. On the top of the left hand grip1002is a menu navigation thumb joystick1008for the operator to switch between various views and menus on the display screen1006by moving the joystick up, down, left and right. The joystick may also be momentarily pressed inward to make a particular selection on the display screen1006. The left hand grip1002also has a separate kill switch button1010next to the joystick1008for normally dumping high pressure fluid pressure from the lances by operating the high pressure dump valve (not shown).

The left hand grip1002also has a safety dump lever1012mounted on its underside and visible inFIG. 29. This dump lever1012is spring loaded and must at all times be depressed by the operator's left hand fingertips gripping the controller1000. This dump lever1012must be depressed in order to complete the electrical circuit to turn the high pressure fluid pump on via high pressure pump start/stop switch1014also mounted on the left handgrip1002in a position spaced ahead or in front of the menu navigation joystick1008. This switch1014may be actuated by the operator's index finger while holding the controller1000in his or her left hand, and depressing the dump lever1012. In addition, this dump lever1012must be continuously depressed to keep the dump valve (not shown) closed in order to supply fluid pressure to the lance nozzle. This dump lever1012operates as a “deadman” switch to dump high pressure fluid to atmosphere in the event that the operator were to let go of the left hand grip of the controller1000.

The right hand grip1004has an X/Y positioner joystick1016for operating the air motors of the vertical and horizontal drive motors114and118on the X-Y frame104. In addition, the right hand grip1004has two spring loaded momentary switches1018and1020located in front of the X/Y positioner joystick1016. These are positioned for easy access by the operator's right hand index finger while the joystick1016is manipulated. The controller1000, as a remote version of the control box108described above, also contains the SBC/SOM processor804and has a controller power switch1022. The controller1000carries a cable connector1024that funnels electrical wire communication between the tumble box110and the other components of the system100such as the tractor102, the encoders114,118,162,126and the analog processor124.

Turning now toFIGS. 30-34, operation of the system100via controller1000will now be described. Prior to operation of the system100via controller1000, a measurement of the target tube sheet pitch and the pattern type is preferably made. This can be done manually, by physically determining the center to center distance between tubes, the edge to edge distance, and whether or not a triangle tube pattern or square tube pattern is used by the tube sheet. This information is entered into the controller1000when the settings screen is selected by maneuvering the menu selection joystick1008to highlight the settings menu, as shown inFIG. 30, and selecting it. The Settings menu (not shown) permits the operator to indicate screen brightness, contrast, vibration level for emergency warnings, etc. The operator then selects Auto Jog, as highlighted inFIG. 31. The screen will advance to that shown inFIG. 32. If the operator selects the highlighted Settings tab, a Job Settings screen, shown inFIG. 33will appear. The measured pitch and hole pattern can then be selected from a dropdown menu. After the pitch and hole pattern are entered, the operator selects “Back” to return to the Auto Jog screen inFIG. 32.

Alternatively, a Pitch Learning mode may be used. InFIG. 30a plan view of the controller1000showing screen1006after an operator turns on the system100by having pressed the controller power switch1022is shown. The operator then selects the Auto Jog option by selecting the highlighted option inFIG. 31. This brings up the AutoJog screen shown inFIG. 32. The user then selects the highlighted “Drive: Auto” selection and toggles it to show “Pitch Learn”. (This Drive selection scrolls between “Auto”, “Pitch Learn”, and “Manual”.) The operator then selects the number of tubes to be cleaned at a time, typically 3 if 3 lances are simultaneously being used, and enters this in the “Moves” selection.

When in Pitch Learn mode, next the operator depresses the dump lever1012with his left hand and presses the high pressure water button1014. The operator then presses the tractor forward button1018to feed the lances into the first 3 tubes, then withdraws them using the tractor Reverse button1020. The controller1000will record 3 tubes in the “Tube Count” register. The operator then taps the X/Y positioner joystick1016in the direction of the next tubes to be cleaned. The system100will automatically senses tubes via sensors150, described in detail above, and advance the number of “Moves” indicated on the screen. The operator then repeats pressing the tractor forward button1018and reverse button1020. This process is repeated until either the last tubes are cleaned in the row or there is a different number of moves left to complete the row. In the latter case, the operator must then change the “Moves” as appropriate to complete operations on the row. The operator then taps the X/Y positioner joystick up or down to move to a new row of tubes. The positioner will automatically move up, down, or diagonally in accordance with the entered Pitch (square or triangular, and the learned pitch distance. The next row of tubes is cleaned in the same fashion. As this process is done, in the Learn mode, the detected Pitch is learned, refined and displayed on the screen as shown inFIG. 33.

After the Pitch is learned, the operator can select Auto in the AUTOJOG menu screen and proceed with automatic cleaning with the learned pitch and depth information. The operator simply taps the joystick1016to the right, and the controller will automatically move to the right three sensed holes. The operator then presses the tractor forward button1018to move the lances101into the aligned set of three tubes to be cleaned, followed by pressing the reverse button1020to withdraw the lances. The operator then taps the joystick1016again to the right to automatically move the lance drive again 3 holes. The process is then repeated until cleaning of the row of tubes is completed. The operator then taps joystick1016up or down to move to the next row and the process sequence is then repeated.

The information processed by controller1000, including heat exchanger name, location, number of tubes, date and time cleaned, etc. number of tubes cleaned, number and location of tube blockages, obstructions encountered and removed, and the status of each tube is important information. This information may be automatically compiled, stored and tracked via external communication from the controller1000to external databases. The information can be utilized to track condition of the heat exchanger over time. This information may be utilized to establish replacement schedules, and identify process issues for asset owners, as well as track efficiencies from crew to crew and identify training opportunities. Finally the collection of such data can be effectively utilized as a permanent record of unbiased data to ensure regulatory compliance.

A multiple lance drive apparatus1200incorporating an autostroke functionality for each lance driven by the drive apparatus is shown inFIGS. 35-43. Referring now toFIG. 35, a belt side view of the apparatus1200is shown with its side cover removed. The drive apparatus1200is a modified version of the lance drive102shown inFIG. 3. This drive apparatus1200has a rectangular box housing1202that includes a flat top plate1204, a bottom plate1206, front and rear walls1208and1210, and two C shaped carry handles1212, one on each of the front and rear walls1208and1210. InFIGS. 35-38, sheet side covers (not shown) are removed so that internal components of the apparatus1200are visible.

Fastened to the front wall1208is an exit hose guide manifold1214. Fastened to the rear wall1210below the carry handle1212is a hose entrance guide manifold1216. Each of these manifolds1214and1216includes a set of hose guide collets1218for guiding one to three flexible lance hoses167(shown inFIGS. 3 and 9) into and out of the housing1202. Each guide collet set1218is sized to accommodate a particular lance hose diameter. Hence the collet sets are changeable depending on the lance size to be driven by the apparatus1200. Each of the manifolds1214and1216includes a sensor, typically a hall effect sensor (not shown) for detecting presence or absence of a metal hose stop element that is fastened to each flexible lance hose167. These sensors are used to stop the apparatus1200when presence of a hose stop element is sensed. One hose stop element is preferably integrated into the threaded hose ferrule to which a nozzle is attached, at the end of each of the lance hoses. This particular hose stop element is configured to prevent inadvertent withdrawal of the flexible lance101out of the heat exchanger tube sheet200and into the drive apparatus1200. The forward manifold1214may also include a physical collet assembly to mechanically prevent flexible lance nozzle105withdrawal into the drive apparatus1200. Another hose stop element is removably fastened to each of the lance hoses167short of the rear manifold1216to prevent over insertion of a flexible lance101beyond the tube being cleaned. These removable hose stop elements may pairs of C shaped metal clamps that are fastened to the hose at a predetermined hose length from the nozzle end to indicate full insertion of the flexible lance through a target tube sheet and tube being cleaned.

A motor side view of the apparatus1200is shown inFIG. 37with its outer side cover removed. The housing1202includes an inner vertical support partition wall1220fastened to the front and rear walls1208and1210and the top and bottom plates1204and1206. This vertical support partition wall1220divides the housing into a first portion and a second portion. The first portion primarily houses hose fittings and splined belt drive motors1222and1224. The second portion is a belt cavity1221through which flexible lance hoses (not shown inFIG. 35-37) are driven, and is shown at least inFIGS. 35, 36 and 37.

In this exemplary embodiment1200, the inner vertical support wall1220carries a pair of pneumatic drive motors1222and1224mounted such that their drive shafts1226and1228protrude laterally through the support wall1220into the second portion, or belt cavity1221, between the inner vertical wall1220and an outer vertical lower support wall1230, shown inFIGS. 35 and 36. Each of the drive motors1222and1224is connected to pneumatic forward feed line1232and reverse feed line1234through a feed manifold1236fastened to the top plate1204. A clamp pressure feed line fitting1238also passes through this feed manifold1236to a hose clamp assembly1244described below. Each of the drive motors1222and1224, shown inFIG. 37, is preferably a compact radial piston pneumatic motor. However, hydraulic or electric motors could alternatively be used.

On the belt side view shown inFIGS. 35 and 36, the belt cavity1221is defined between the inner vertical wall1220and the outer lower support wall1230. A separate upper outer support wall1240aligned with the lower outer support wall1230provides a rigid joint between the front and rear walls1208and1210while providing a visible space between the entrance and exit guide manifolds1216and1214. This spacing helps an operator thread up to three lances laterally into and through the belt cavity1221between an endless drive belt1242and a vertically arranged hose clamp assembly1244. Each of the support walls1220,1230and1240is preferable a flat plate of a lightweight material such as aluminum or could be made of a structural polymer with sufficient strength and rigidity to handle the motor operational stresses involved.

The upper outer support wall1240carries a set of electrical connectors1243for communication of sensed hose position, hose stop presence and belt position via the drive motor direction and position sensors described below, and a set of 14 LED lights1245to indicate the status of each of these elements during drive apparatus operation.

A perspective view of the apparatus1200with the upper and lower outer vertical support walls1240and1230removed is shown inFIG. 36. Each of the motor drive shafts1226and1228has an axial keyway fitted with a complementary key (not shown) that engages a corresponding keyway in a cylindrical splined drive roller1246. Thus each drive roller1246is slipped onto and keyed to the drive shaft so as to rotate with the drive shaft1226or1228. Each splined drive roller1246has its outer cylindrical surface covered with equally spaced splines extending parallel to a central axis of the roller1246. The distal ends of each of the drive shafts1226and1228extends through the lower outer support wall1230and are primarily laterally supported from plate1220. Additional lateral support for the distal ends of each of the drive shafts1226and1228is provided by the lower outer support wall1230via cone point set screws engaging a V groove (not shown) in each of the shafts1226and1228.

Each of the drive shafts1226and1228may extend fully through the splined drive rollers1246or the drive motors1222and1224may each be fitted with a stub drive shaft which fits into a bearing within the proximal end of each of the splined drive rollers1246. A separate bearing supported drive shaft1226or1228extends out of the distal end of each drive roller1246and is fastened to the support wall1230via cone point set screws. In such an alternative, the drive rollers1246become part of the drive shafts1226and1228.

Spaced between the two splined drive rollers1246is a set of four cylindrical guide rollers1248that are supported by the lower outer support wall1230via a vertical plate1250and a pair of rectangular vertical spacer blocks1252that are through bolted to both the lower outer support wall1230and inner vertical wall1220through the vertical plate1250via bolts1254. While the bolts1254pass through the vertical plate1250, their distal ends extend further through, and are threaded into holes through the inner vertical wall1220.

Tension on the endless belt1242is preferably provided by a tensioner roller1258between the spacer blocks1252that is supported from the inner vertical plate1250on an eccentric shaft1260, and accessed through an opening1262in the inner vertical wall1220, shown inFIG. 37. Rotation of this eccentric shaft1260essentially moves the tensioner roller1258through a slight arc downward or upward to provide more or less tension on the belt1242.

To replace the belt1242, the four bolts1254are loosened and screws holding the outer lower wall1230to the front and rear walls1208and1210are removed. The cone point set screws engaging a V groove (not shown) in each of the shafts1226and1228are then removed. The assembled structure including the vertical plate1250, spacer blocks1252, belt1242, drive rollers1246, and guide rollers1248can then be removed as a unit by sliding the drive rollers1246off of the keyed shafts1226and1228.

Each of the splined drive rollers1246preferably has equally spaced alternating spline ridges and grooves around its outer surface which are rounded at transition corners so as to facilitate engagement of the complementary shaped lateral spline ridges and grooves in the inner side or surface of the endless belt1242. Elimination of sharp transitions at both ridge corners and groove corners lengthens belt life while ensuring proper grip between the rollers and the belt. The outer surface portion or cover of the endless belt1242is preferably flat and smooth to prevent undesirable hose abrasion and degradation and is preferably formed of a suitable friction material such as polyurethane. The inner side portion of the belt1242is preferably a harder durometer polyurethane material bonded to the outer side cover. For applications with significant hydrocarbons or high lubricity products, grooves machined across the cover at 90° to the direction of belt travel may be utilized for improved traction performance against the flexible lance hose.

Spaced above the belt1242in the belt cavity is a lance hose clamp assembly1244including an idler roller assembly1270. This exemplary clamp assembly1244includes a multi-cylinder frame1272fastened to the top plate1204of the housing1202. The multi-cylinder frame1272carries two or three single acting pneumatic cylinders with pistons1274(shown inFIG. 38) that are each connected to a carrier block1276and connected together via a pair of parallel spaced idler carrier frame rails1278. Six idler roller sets1280are carried by the frame rails1278, each vertically positioned directly above either one of the drive rollers1246or one of the guide rollers1248. Each piston1274may be spring biased such that without pneumatic pressure, the pistons1274are all withdrawn or retracted fully into the multi-cylinder frame1272so as to provide access space between the idler roller sets1280and the drive belt1242for insertion and removal of flexible lance hoses.

One set of idler rollers1280is made up of three independent spool shaped bearing supported rollers1282shown in the sectional view through the apparatus1200shown inFIG. 38. This particular set1280of idler rollers1282is positioned adjacent hall effect sensors1300,1302, and1304, mounted on a circuit board1285fastened to the underside of the carrier block1276, to detect distance traveled by each hose being driven through the drive apparatus1200. Each roller1282is a spool shaped roller having a central concave, or U shaped, groove bounded by opposite circular rims1283. One of the rims1283of each roller1282, preferably an inboard rim1283, carries a series of 24 magnets embedded around the rim1283, each having an opposite polarity in series facing radially outward.

The printed circuit board1285fastened to the underside surface of the upper support block1276carries12hall effect sensors1300,1302, and1304each arranged adjacent one of the rims1283. As each roller1282rotates, for example, by 15 degrees, one of the magnets passes beneath its adjacent sensor1300,1302, or1304on the pcb1285and a polarity change is detected. These changes are counted and converted to precise relative lance distance traveled for that particular lance (not shown). In this way, very precise distance traveled by the lance can be determined irrespective of the distance traveled by an adjacent lance driven by the drive apparatus1200.

Each idler roller set1280is carried on a stationary axle1290fastened between the idler frame rails1278. Only one idler roller set1280needs to have separate rollers1282. The other 5 idler roller sets1280each preferably is a bearing supported cylindrical body having three axially spaced annular spool shaped concave grooves each being complementary to the anticipated lance hose size range. These annular grooves may be V shaped, semicircular, partial trapezoidal, rectangular, or smooth U shaped so as to provide a guide through the apparatus1200and keep the flexible lances each in desired contact with the endless belt1242during transit. Preferably the idler rollers1280and the individual rollers1282are made of aluminum or other lightweight material capable of withstanding bending loads and each groove has a concave arcuate cross-sectional shape. Each groove may alternatively be a wide almost rectangular slot with corners having a radius profile to allow the hoses to have limited lateral movement as they are fed through the apparatus1200. This latter configuration is preferred in order to accommodate several different lance hose diameters in the drive apparatus1200.

In use, the drive apparatus1200may be utilized with one, two, or three flexible lances simultaneously. In the case of driving one lance, such a lance would be preferably fed through the center passage through the inlet manifold1216and beneath the center groove of the idler rollers1280. When two lances are to be driven, the inner and outer passages through collets1218would be used. If three lances are to be driven, one would be fed through each collet1218and corresponding groove of each idler roller1280.

In alternative embodiments, more than three lance drive paths may be provided such as 2, 4 or five. Electrical or hydraulic actuators and motors may be used in place of the pneumatic motors shown and described. Although a toothed or spline endless belt is preferred as described and shown above, alternatively a smooth belt or grooved belt with wider spline spacing could be substituted along with appropriately configured drive rollers. The guide rollers1248are shown as being smooth cylindrical rollers. They may alternatively be splined rollers similar to the drive rollers1246.

One of the splined belt drive motors, motor1222in the illustrated embodiment1200, is configured with a differential hall effect sensor1289to monitor speed and direction of rotation of the drive motor1222, and hence lance travel along the belt1242through the drive apparatus1200. A separate plan view of drive motor1222is shown inFIG. 39, with its outer cover shown transparent. An annular notched target disc1291is fastened to the motor rotor inside the motor housing1293, having spaced notches forming, in this illustrated embodiment, 18 teeth1295. The differential hall sensor1289fastened to the housing1293senses passage of each of these teeth1295and outputs a voltage change signal for each edge transition as a tooth passes beneath the sensor1289. The signal output is indicative of direction of rotation and speed, which mathematically equates to belt position and hence lance travel distance, assuming no slip between belt and lance hose.

By comparing the position of the lance hoses, i.e. distance traveled as sensed from the follower roller set sensors1300,1302, and1304, for each of the lance hoses, with the belt drive motor speed and direction sensed distance from the signal output of sensor1289, any mismatch is correlated to lance to belt slippage. For example, when driving three lances, if a large mismatch on only one lance occurs, in a three lance drive operation, this is typical of a blockage or restriction in that particular tube being cleaned.

If all the lances, 3 in the illustrated case, have a similar mismatch with respect to the belt drive motor sensed position and/or feed distance, this will be indicative of insufficient clamp pressure. In this instance the operator can simply increase clamp pressure to compensate for the mismatch. The operator can then re-zero the lance position and look for subsequent mismatch. Alternatively an automatic control system can perform this function, as is described in more detail below. In such a case the clamp pressure may be automatically increased to minimize slippage, up to a predetermined maximum applied pressure applied to the follower rollers1280.

In the event of a single lance hose mismatch, as first described above, this indicates a restriction, or blockage, occurring in the tube being cleaned. The sensed mismatch preferably is used to trigger an autostroke sequence of motor1222instigating reversals as generally described above, to move the lance hoses back and forth in the tubes being cleaned, until the blockage or restriction is reduced or eliminated, as determined by re-zeroing the position of the mismatched lances and continuing the cleaning operation as needed, until another mismatch above an operator determined threshold occurs.

The drive apparatus1200preferably includes the comparator circuitry to compare the signals from each of the sensors1300,1302, and1304with the signal from the drive motor sensor1289. The drive apparatus1200may also include a comparator that compares the signals between each of the sensors1300,1302and1304, as the lance position of each lance should be relatively close to each other since the only drive force is from the contact with the drive belt1242. Alternatively the comparator circuitry may be handled via microprocessor in a system controller such as hand held controller1000, separate from the apparatus1200. In either case, an exemplary signal processing circuit is shown, in simplified block diagram form inFIG. 40and process flow diagramsFIGS. 41, 42 and 43.

A simplified functional block diagram1350for autostroke control for the apparatus1200is shown inFIG. 40. Motor sensor1389feeds an input into three comparators1360each of which in turn send an input to controller1400. At the same time, the sensors1300,1302and1304also send signals to the comparators1360. The controller1400serves three major functions: autostroke910to remove tube blockages, clamp pressure control950, and emergency dump valve actuation. The autostroke functionality is described below with reference toFIGS. 41 and 42. The clamp pressure may be adjusted manually or may be controlled automatically as described inFIG. 43.

The emergency dump signal actuation function of controller1400simply sends a signal to the valve driver board MCU in the tumble box110if the controller1400receives a signal through the comparators1360that exceeds a second threshold from any one of sensors1300,1302or1304. This second threshold is indicative of a reversal of count direction from the sensors1300,1302, or1304or an excessive rate of lance speed. If any one lance hose reverses direction while the drive motor sensor1258is sensing forward motion of the motor, this indicates that the lance hose is being pushed backward, which should not ever happen unless a catastrophic event such as nozzle breakage or hose rupture during system operation is occurring. If such an event is sensed, a signal is sent to the valve driver board in the tumble box110to immediately divert high pressure cleaning fluid pressure to atmosphere by de-energizing the dump valve. Utilizing the follower roller position sensors1300,1302, and1304for this purpose permits very fast response times, on the order of milliseconds, to initiate an automatic dump action which can greatly diminish the chances of such an unanticipated event from resulting in injury to an operator of the apparatus100or1200.

Operational control of the apparatus1200, basically called a smart tractor, begins in operation900, when a feed forward operation is selected by the operator on a cleaning system control box108. This control box108may be floor mounted or may be the hand-held controller1000, described above with reference toFIGS. 28-34, that communicates either wired or wirelessly with the apparatus1200. For ease of explanation here, the hand held controller1000is described. Once feed forward operation is selected, control transfers to tractor forward operation902which queries in operation904whether the Drive forward button1018has been pressed. If the answer is yes, control transfers to comparator operation906. If, however, in query operation904, the Drive button1018has not been pressed, control immediately transfers to stop operation911where tractor forward operation is stopped.

Assuming the Drive button1018has been pressed, forward operation902energizes the drive motors1222and1224causing the endless belt1242to pull 1, 2 or 3 lances along the pathway between inlet manifold1214and outlet manifold1216through the apparatus1200. As the lances move along the endless belt1242, their movement causes the follower rollers1282to rotate, sending signals, picked up by sensors1300,1302and1304, to comparators1360. At the same time, sensor1289on motor1222sends a similar signal to each of the comparators1360.

Operation906receives linear lance position information from sensors1300,1302, and1304via the circuit board1285for each lance. Comparator operation906also receives belt position information from the sensor1289on the drive motor1222. In operation906, the received signals are converted to actual lance feed distances and the expected feed distance is compared to the actual feed distance of each lance.

Control then transfers to query operation908where the question is asked whether expected feed to actual feed of each lance differs over time. In other words, whether there is a mismatch between expected feed distance and actual distance fed. If below a user settable difference, the answer is NO, a “continue drive” control signal is sent back to operation902and the tractor continues to drive the lances forward. On the other hand, if there is a substantial difference in expected to actual feed for any one of each individual lance, then the answer is Yes, control transfers to Autostroke subroutine operation910, shown in detail inFIG. 42. On the other hand, if there is a substantial difference in expected to actual feed, i.e. a mismatch, for more than one individual lance detected in operation908, this is indicative of insufficient clamp pressure, and the controller1400transfers control to clamp pressure operational sequence950described inFIG. 43.

An autostroke routine910begins in operation912. Control then transfers to reset operation914where the lance to motor difference for each lance is set to zero and an incrementing counter is set to zero. Control then transfers to operation916where the increment counter is advanced by 1. Control then transfers to operation918where drive apparatus1200is signaled to drive backward for N increments. Control then transfers to operation920, where the drive apparatus1200is signaled to drive forward N+1 increments. Control then transfers to query operation922.

Query operation922asks whether the counter value is greater than or equal to 10. If the answer is no, control transfers back to operation916where the counter is incremented again and the process operations918,920and922are repeated. If the answer in query operation922is yes, the counter is greater than or equal to 10, control transfers to query operation924which asks whether a mismatch between lance position and motor position counts still exists. If the answer is yes, a mismatch is still present, this indicates that there is still a blockage or restriction in the target tube or tubes. Control transfers to operation926.

In query operation926, the question is asked whether the apparatus1200feed rate is at a minimum. If the answer is yes, control transfers to stop operation928. This indicates that an unremovable obstruction has been encountered, requiring manual operator action to mark the tube as blocked or take other appropriate action. In query operation926, if the answer is no, feed rate is not yet at minimum, control transfers to operation930.

In operation930, the tractor feed rate of apparatus1200is reduced. Control then transfers back to operation914where the lance to drive position mismatch is set to zero and the incrementing counter are set to zero, and the iterative process of operations916through924is repeated.

On the other hand, if in query operation924, there is no mismatch present, this means that either no obstacle is now sensed, i.e. the obstacle has been cleared, and control returns to operation902, where normal tractor drive forward operation is resumed, until the drive button in operation904is released, which stops tractor forward feed in operation911.

A process flow diagram950of the controller1400is shown inFIG. 43for adjusting the clamp pressure of pistons1274applying force against the follower rollers1280to press follower rollers1280against a set of one or more hoses (not shown) being driven along the endless belt1242. Basically, if there is a mismatch as determined by comparators1360for more than one lance hose, this is potentially indicative of insufficient clamp pressure or force, and hence the position of lances167are not together. The process begins in operation952. The controller1400senses if a lance hose registers a mismatch in operation952. Control then transfers to query operation954, which asks if there is more than one lance comparator signaling a mismatch. If so, control transfers to query operation956. If not, control transfers back to operation902described above.

In query operation956, the query is made whether clamp pressure is at or above a predetermined maximum pressure. If the answer is yes, control transfers to operation960where a flag is sent and clamp pressure control may be transferred to manual for the operator to assess and take appropriate action. If the answer in query operation956is no, pressure is not at maximum, control transfers to operation958, where clamp pressure is increased by a predetermined amount, such as 2 psi. Control then transfers back to query operation954and operations954, through956are repeated until the mismatch determined in operation954is less than or equal to 1. Control then transfers back to operation902described above.

Controller1400may also be configured via process950to automatically synchronize position of all lance hoses167being driven by the drive1200and maintain synchronization between these lance hoses167. For example, during lance insertion into the heat exchanger tubes, if a mismatch between the several lance positions is less than the maximum, but exists, they will not be together. When a first lance encounters its full insertion hose stop the controller1400continues to drive apparatus1200until all three lances167are at full insertion as sensed by contact with the hose stops. When the operator instructs the controller to reverse direction, the lances167will begin withdrawal in synchronization. During reverse direction of the lance hoses167if a mismatch between the sensed positions of each lance hose is again sensed, less than the maximum, which would indicate an obstruction, the controller1400continues to withdraw the lance hoses167until all of the hose crimps are detected. Controller1400signals the drive motors to stop, with all lance hoses167resynchronized in the fully withdrawn position. The drive1200may then be repositioned to clean another set of tubes.

FIG. 44is an exemplary control/power distribution diagram of an alternative embodiment of an apparatus2000in accordance with the present disclosure similar to apparatus100shown inFIGS. 1-43and described above. Apparatus2000includes a smart tractor drive1200that is mounted on an X-Y positioner104that is in turn fastened to a tube sheet200. The tractor1200receives pneumatic power and optionally electrical power from a tumble box110. This tumble box110includes a valve driver board, connections from a high pressure pump (not shown), connections from a pneumatic pressure source such as an air compressor (not shown), and various pneumatic valves for controlling air pressure to and from the horizontal drive114and vertical drive118, and optionally may house a pneumatic/electrical motor generator, e.g. an air motor generator (AMG) to provide control power and sensor power for the various elements of the apparatus2000. Alternatively electrical power may be conventionally supplied through external connection.

The tumble box110communicates with a control box108which may be floor mounted as illustrated inFIG. 1or preferably may be a hand held remote controller1000as described with reference toFIGS. 28-34above. This control box108, or controller1000includes a display1006, a kill button1010, left joystick1008, right joystick1016, dump trigger1012, forward and reverse feed controls1018and1020, a battery, and a haptic feedback motor for generating a vibrational signal to the operator holding the controller1000.

The tractor1200carries a belt drive sensor1289and three lance position sensors128as above described, and at the rear of the tractor1200a hose stop sensor162and at the front end a set of hose crimp sensors140. These hose crimp and hose stop sensors may be as above described or each may be any suitable metal sensing device that can indicate the presence or absence of either a hose crimp (that indicates a connection to a nozzle at the end of each of the lance hoses167), or a physical stopper such as a conventional “football” fastened to the lance hose167that signifies full insertion of the lance hose through the target heat exchanger tubes. Each of these sensors140or162may each optionally be a physical switch.

This alternative apparatus2000, shown inFIG. 44, does not include the sensor heads150and analog processor124as above described. The bracket120attached to the X-Y positioner104, and guide tubes122are, however provided, and the hole locating sensor heads150may optionally be added.

Many variations are envisioned as within the scope of the present disclosure. For example, all processing circuit components of the control box108may be physically housed therein. Alternatively, the components within the control box108could be integrated into the drive apparatus102or into the housing of the drive apparatus1200. In the case of drive apparatus1200, the control circuitry may be housed in the separate hand-held controller1000described above. The number of drive reversals in the Autostroke sequence may be any number. A value of >=10 was chosen as merely exemplary. In alternative embodiments, electrical or hydraulic actuators and motors may be used in place of the pneumatic motors shown and described herein. Different automated routines and subroutines than as described above may be utilized to control the operation of the apparatus1200. In addition, the apparatus1200may be configured with physical status lights to indicate to the operator mismatches between lances and the drive motor, lance relative position, as well as such things as feed rate and other indications of proper operation. These may include lance withdrawal stop indicators and lance insertion stop indicators positioned on the inlet and outlet manifolds1214and1216or on the side of the housing1202as shown inFIG. 35. Alternatively, these indicators may be reflected in popup warnings displayed on the LCD screen1006of the hand-held controller1000. The belt drive sensor1289described above, may, instead of being mounted on the drive motor1222, may instead be mounted to any one of the guide rollers1280. These indicators, or indications, may be utilized by the operator to monitor and adjust synchronization of the lances being driven by the apparatus1200when they reach the fully inserted position by contact with the lance insertion stop, and vice versa, when the lances are fully withdrawn, via contact with the hose crimps. This permits the operator to adjust the lance positions such that they all start from an aligned position together, and the operator can adjust for and reposition one of the lances that gets out of alignment with the other lances during either an insertion or retraction operation.

The hose clamping pressure, or force may be created and managed as above described. Alternatively, the hose position sensing may be accomplished using a separate assembly in the tractor housing using a spring biased set of follower rollers and position sensors rather than the set specifically as above described.

The handheld controller1000may be shaped differently than as is shown inFIGS. 28-34. The embodiment illustrated is merely one exemplary configuration. The controller1000may be configured with a memory to store and recall a plurality of maps of various tube sheet configurations and layouts such that operation of the sensor head(s)150can be utilized more as an assist to help generate a map. The control box108may not be or may not include a hand held controller1000. The connections between the control box108or hand held controller1000and the tumble Box104may be via wireless communication such as via Bluetooth. The present disclosure describes a guide assembly106with three guide tubes. However, a set of five guide tubes or one single guide tube may be used instead of three guide tubes. Regarding the arrangement of receive coils132on PCBs152, in addition to the options shown above, the annular PCB152containing the receive coils132may be divided in to two symmetrical C-shaped portions. Each C-shaped portion may be mounted to one end of the three guide tubes122. This configuration of PCBs152can accommodate smaller pitches in the tube sheets200. Furthermore, while three AC pulse sensors150are described herein, other embodiments may be configured to utilize only one, on only one guide tube122, or may be configured to utilize one on each of the outer guide tubes122.

The apparatus100described above includes an X/Y positioner frame104. However, other configurations of such a smart drive positioner are also within the scope of the present disclosure. For example, a positioner that essentially utilizes a rotator fastened to one side or edge of the tube sheet102and having an extensible arm that radially extends from the rotator, and carries the smart tractor drive apparatus102along the arm could also be utilized in accordance with the present disclosure. In such an alternative, the controller1000would be essentially the same, except that the joystick1016right tilt would simply rotate the rotator clockwise, the left tilt would simply rotate the rotator counterclockwise, and the forward and rearward tilt would move the smart tractor drive apparatus102along the arm. The conversion between X/Y coordinates and essentially polar coordinates is a simple mathematical calculation and easily accomplished in software for use in such an arrangement.

All such changes, alternatives and equivalents in accordance with the features and benefits described herein, are within the scope of the present disclosure. Such changes and alternatives may be introduced without departing from the spirit and broad scope of our disclosure as defined by the claims below and their equivalents.