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. Specifically, the present invention relates to a flexible high pressure fluid cleaning lance tractor drive apparatus as defined in the preamble of claim 1, and as illustrated in
One auto-indexing system is described in
Another apparatus for a tube sheet indexer is disclosed in
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.
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 claimed invention includes 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.
Another embodiment of a flexible high pressure fluid cleaning lance tractor drive apparatus in accordance with the present disclosure 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 and an endless belt is 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 are each aligned above one of the at least one spline drive roller and guide rollers. The bias member is operable to press each follower roller toward one of the spline drive rollers and guide rollers to frictionally grip at least one flexible lance hose when the at least one flexible lance hose is sandwiched between the follower rollers and the endless belt.
A lance position assembly is fastened to an inlet or rear wall of the housing. This lance position assembly includes a sensor roller having a roller portion adapted to engage the at least one flexible lance hose passing through the housing and a magnetic ring portion adjacent the roller portion. An idler roller is adapted to press against the flexible lance hose to maintain the lance hose engaged with the sensor roller, and a magnetic sensor module is fastened to the rear wall of the housing adjacent to the sensor roller that is operable to sense magnetic field fluctuations in the magnetic ring portion of the sensor roller as the sensor roller rolls along the flexible lance hose.
The magnetic ring portion is a multipole magnetic ring. The idler roller is pneumatically biased against the flexible lance hose. The lance position assembly preferably includes a second sensor roller for engaging a second flexible lance and a second idler roller adapted to press against the second flexible lance hose to maintain the second flexible lance hose engaged with the second sensor roller. Further, preferably the lance position assembly includes a third sensor roller for engaging a third flexible lance and a third idler roller adapted to press against the third flexible lance hose to maintain the third flexible lance hose engaged with the third sensor roller.
The magnetic sensor module is operable to separately sense magnetic field fluctuations in the first, second and third magnetic ring portions as the first, second, and third sensor rollers roll along each respective flexible lance hose. This magnetic sensor module sends sensed separate magnetic field fluctuation signals to the hand held controller for processing.
A crimp and lance stop assembly is removably fastened to the lance drive. This crimp and lance stop assembly includes an induction stop sensor having at least one bore therethrough fastened to a lance guide tube support receiving the at least one flexible lance hose therethrough. The induction stop sensor is adapted to sense presence of a flexible lance hose end crimp when the flexible lance hose end crimp enters the at least one bore. Preferably the induction stop sensor has three bores therethrough each configured to separately sense presence of a flexible lance hose end crimp entering the respective through bore.
A flexible lance hose stop element in accordance with the present disclosure is configured to be installed on a flexible lance hose being fed into and through a flexible lance drive apparatus described above. The hose stop element includes an elongated body configured to wrap around and grip a flexible lance hose. The elongated body has a first half and a second half removably fastenable together via threaded fasteners.
Each half has a cylindrical stop portion having a first outer diameter and a shoulder extension portion having a different outer diameter less than the first outer diameter to enable the shoulder extension portion to slidably extend within a stop block on a lance drive apparatus and prevent passage of the cylindrical stop portion into the stop block. The first half and the second half are identical in size and shape, and preferably the hose stop element has a shoulder portion between the cylindrical stop portion and the shoulder extension. This shoulder portion engages the stop block to prevent entry of the cylindrical stop portion into the stop block, and at least the shoulder extension portion is made of metal.
An embodiment in accordance with the present disclosure may be viewed as a flexible high pressure fluid cleaning lance tractor drive apparatus that includes 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. A side surface of each guide roller and the at least one spline drive roller is tangent to a common plane between the rollers, and 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. A bias member supports 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 at least one flexible lance hose when the at least one flexible lance hose is sandwiched between the follower rollers and the endless belt. A crimp and lance stop assembly is removably fastened to the housing and includes an induction stop sensor having at least one bore therethrough fastened to a lance guide tube support receiving the at least one flexible lance hose therethrough, wherein the induction stop sensor is adapted to sense presence of a flexible lance hose end crimp when the flexible lance hose end crimp enters the at least one bore.
The induction stop sensor preferably has three bores therethrough each configured to separately sense presence of a flexible lance hose end crimp entering the respective through bore. The lance drive apparatus further preferably has a lance stop block fastened to an inlet wall of the housing configured to detect presence of a flexible lance hose stop element fastened to the at least one flexible lance hose. This lance stop block, fastened to the inlet wall of the housing, carries another induction sensor configured to detect the flexible lance hose stop element.
The flexible lance hose stop element comprises an elongated body configured to wrap around and grip a flexible lance hose, the elongated body having a first half and a second half removably fastenable together via threaded fasteners, each half having a cylindrical stop portion having a first outer diameter and a shoulder extension portion having a different outer diameter less than the first outer diameter to enable the shoulder extension portion to slidably extend within the stop block on the lance drive apparatus and prevent passage of the cylindrical stop portion into the stop block.
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.
The lance hose drive 102 and the guide assembly 106 are separately shown in
Each of the guide tubes 122 is 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 sensor 150 in accordance with the present disclosure is mounted at the distal end of each guide tube 122. An enlarged distal end of the tractor drive 102 and guide assembly 106 is shown in
Each of the cups 130 carries therein a receive coil 132. Alternatively, the receive coils 132 may each be wrapped around a locating pin on the flange 128 rather than being disposed in a cup 130 as shown. A transmit coil 134 is wound around the distal end of each tube 122 and adjacent the receive coil cups 130 such that the transmit coil 134 and receive coils 132 are closely coupled. One embodiment of each guide tube 122 may have a ceramic portion that interfaces with the metal of the guide tube 122 toward the distal end of the guide tube. This non-interfering ceramic portion distances the transmit coil 134 from the metal of the guide tube 122.
A simplified drawing of the coil arrangement is shown in
The receive coils 132 are 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 coils 132 if no other conductive material or magnetic fields are in the proximity of the sensor head 150. The coils 132 can be tilted to increase sensitivity to eddy currents in specific locations of the sensed volume as shown in
An exemplary embodiment of one receive coil 132 arrangement is illustrated in
In an alternative embodiment, the receive coils 132 may be printed on one or more printed circuit boards (PCBs) 152. The PCBs 152 containing the receive coils 132 are attached to the distal end of the guide tube 122 adjacent the transmit coil 134. The use of PCBs 152 allows for a variety of receive coil 132 shapes and lengths to be manufactured. The PCB 152 also provides mechanical stability to the potentially fragile receive coils 132.
Various exemplary embodiments of receive coils 132 on PCBs 152 are shown in
The magnetic field 136 generated by the transmit coils 134 wrapped around the distal end of the tube 122 is illustrated in
Referring now to
The transducers 140 preferably magnetically sense presence of a crimp and send a control signal therefore to control circuitry for the lance drive 102 to de-energize the "retract" lance drive motors when a crimp is sensed. In addition, the transducer 140 signal 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 transducers 140 may be used together to synchronize lance position. The lance tractor drive 102 may be driven until all lance footballs (indicating full lance insertion) or crimps (indicating full lance withdraw from the heat exchanger) are detected.
Turning now to
All of the components that are mounted on the positioner frame 104 including the air motors, 114, 116, the sensor head 150 and guide assembly 106, and the lance hose drive tractor 102 may 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 apparatus 100 in accordance with the present disclosure that a tumble box 110 be 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 apparatus 100 in 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 box 110 takes pneumatic pressure and converts it to electrical power for all the sensors, and electrical controls of the apparatus 100. The tumble box 110 includes a sealed pneumatic to electrical power generator as well as all the operational air control valves for selectively supplying air pressure to air motors 114, 118, and to the forward and reverse air motors within the tractor drive 102, as well as emergency high pressure water dump valve control and other pneumatic functions.
The tumble box 110 also self generates electrical power for the control circuitry located in the electric control box 108 for overall operation of the apparatus 100 and automated process software. The tumble box 110 and electric control box 108 are typically located out away from the area of high pressure, such as 20-40 feet from the components 102, 104 and 106. For example, the tumble box 110 may be 5-25 feet from the X-Y positioner frame 104 and the control box 108 another 5-25 feet from the tumble box 110. 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 box 108 via 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 to
The electric control box 108 signals and controls the air valves in the tumble box 110 to provide pneumatic power to the vertical drive air motor 118 and horizontal drive motor 114. In turn, each of these pneumatic drive motors 114 and 118 has a pair of position encoders that feed through the tumble box 110 to the control circuitry in the control box 108 to provide x and y coordinate position data to the control circuitry. Each of the sensor amplifier block 124, the front hose stop collet block 126 and rear hose stop block 160, the tumble box 110 and the x-y positioner drives 114 and 118 has an internal master control unit (MCU) for processing signals needed to communicate position information to the software resident in the control box 108. Furthermore, the control box 108 contains a database and memory for a position monitor/map of the tube sheet to which the apparatus 100 is attached.
The detection system utilizing sensors 150 traverses the tube sheet 200 until an "event" is detected by an abrupt change in eddy current sensed by the receive coils 132. 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 sensors 132, each aligned on the x and y axis respectively of the tube sheet 200. Thus an Rx N and Rx S receive coils 132 are analyzed as the Rx Y axis pair. An Rx E and Rx W receive coils 132 are 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 sensors 132. 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.
In
The program begins in operation 170 where the user turns the system on. Control transfers to Display message block 172 which shows the user the instruction to position the guide tube assembly in a central location over the tube sheet 200 and centered over a hole 202 (or series of 3 holes) and press enter. Control then transfers to Start operation 174. The user is then asked to confirm the lances are fully retracted in operation 176. If the lances are fully retracted their position will be sensed by the transducers 140 sensing the footballs of all three lances indicating full retraction of the lance hoses. If so, query is then asked of the user in operation 178 whether to proceed. If so, in operation 180, the Position Map is then initialized with the apparatus 100 given or set at the present location and this location is initialized as location c (0,0). Control then passes to The Initial Hole Jog sequence 210 shown in
The overall High Level operation sequence shown in
Referring now to
The Clean Tubes sequence 300 begins in operation 302 where the lance drive 100 feeds three lances into the tubes to be cleaned until the hose stops are detected by the rear football transducers 162. Control then transfers to query operation 303 which asks whether all lances are through the tubes 202 such that all rear football transducers 162 indicate receipt of a football. If not, lance drive 100 continues to feed lances until all transducers 162 sense football presence. Control then transfers to operation 304. In operation 304, the lance drive 100 reverses direction and feeds the lances out. Control transfers to query operation 306 which asks whether all transducers 140 indicate the presence of a football or hose crimp. If so, control transfers to stop tractor operation 308. If not, lance drive 100 continues to feed the lances out until all hose footballs are sensed by transducers 140. Control then transfers to operation 310 where the position monitor is updated to indicate the tubes cleaned. Control then transfers to return or end operation 312. Control then returns to the high level operations shown in
Once the first set of 3 tubes are cleaned in sequence 300, control transfers to Find Tubes sequence 400 shown in
If a move left operation is not available control transfers to query operation 608 which asks whether a move right is available. If yes, control transfers to operation 610 in which a signal is sent to the air motor 118 to jog the drive 102 right. If the answer in operation 608 is no, control transfers to query operation 612 which asks if a move up available. If yes, control transfers to operation 614 in which a signal is sent to the air motor 114 to jog the drive 102 up.
If the answer in query operation 612 is no, control transfers to query operation 616 which asks whether a move down is available. If the answer is yes, control transfers to operation 618 in which a signal is sent to the air motor 114 to jog the drive 102 down.
If the answer in query operation 616 is no, control transfers to operation 620 which logs that no moves are available. Control then transfers to query 622 which then asks the user whether the jog sequence operation is complete, and, if so, updates the position monitor log in process operation 624. If the query 622 answer is no, control transfers to query operation 626. 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 operations 606, 610, 614 or 618, control transfers to a query process operation 628, 630, 632 or 634 respectively 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 operation 626. If the answer is a hole, control transfers to operation 624 where the position monitor database is updated. Control then transfers from operation 624 to end the Identify Object process 500.
In query operation 626, the question is asked whether the location is a new or known obstacle. If the answer is a known obstacle, control transfers to query operation 636 which asks the position monitor whether the obstacle may be automatically jogged around. If yes, control transfers to auto-jog operation 638 where either the air motor 114 or 118 is instructed to move a predetermined distance to move past the known area. Control then transfers to operation 640 where 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 operation 624. If the answer in operation 640 is an obstacle, control transfers back to query operation 626. Once the position monitor is updated in operation 624, control passes to the end Identify Object process 500.
If the answer in query operation 626 is that the obstacle is new, control transfers to operation 642 where the user is prompted for a manual jog around the obstacle. When a manual Jog is completed, control transfers to operation 644 which 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 operation 624 where the position monitor is updated. If the position monitor indicates an obstacle, control passes back to query operation 636.
The process 500 is shown in
On the other hand, if the answer in query operation 514 is that the obstacle type is classified as known on query 514, control transfers to operation 522 where the obstacle type is recognized. Control then transfers to operation 512 where the position monitor database is updated with the recognized type. Control then passes to End operation 520. Control then passes back to whatever process called the Identify Object process 500.
When the initial set of three holes have been cleaned in process 300, control transfers to Find Tubes process 400, which is shown in
On the other hand, if the answer in operation 408 is 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 sequence 750 shown in
The Center on Holes sequence 430 is shown in
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 drive 102 would 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.
In addition, many changes may be made to the apparatus described above. For example, electric stepper motors may be utilized instead of the air motors 114 and 118 and the air motors in the lance tractor drive 102 in an all electrical version of the apparatus 100. The lance hoses (not shown) may be configured with coding such as RFID tags so that the position transducers or encoders 162 and friction wheel encoders 166 and 168 may be other than specifically as above described. In an all electrical design of the apparatus 100, the tumble box 110 may be eliminated and/or the sensor amplifier block 124 may be relocated, miniaturized, or incorporated into the electrical control box 108 or the hose stop collet block 126. The apparatus 100 may require less than three sensors 150, or less than eight receive coils 132 in each sensor head 150. Thus the above description is merely exemplary.
One exemplary embodiment of a controller box 108 is a handheld remote controller 1000 shown in perspective top and bottom views in
The left hand grip 1002 also has a safety dump lever 1012 mounted on its underside and visible in
The right hand grip 1004 has an X/Y positioner joystick 1016 for operating the air motors of the vertical and horizontal drive motors 114 and 118 on the X-Y frame 104. In addition, the right hand grip 1004 has two spring loaded momentary switches 1018 and 1020 located in front of the X/Y positioner joystick 1016. These are positioned for easy access by the operator's right hand index finger while the joystick 1016 is manipulated. The controller 1000, as a remote version of the control box 108 described above, also contains the SBC/SOM processor 804 and has a controller power switch 1022. The controller 1000 carries a cable connector 1024 that funnels electrical wire communication between the tumble box 110 and the other components of the system 100 such as the tractor 102, the encoders 114, 118, 162, 126 and the analog processor 124.
Turning now to
Alternatively, a Pitch Learning mode may be used. In
When in Pitch Learn mode, next the operator depresses the dump lever 1012 with his left hand and presses the high pressure water button 1014. The operator then presses the tractor forward button 1018 to feed the lances into the first 3 tubes, then withdraws them using the tractor Reverse button 1020. The controller 1000 will record 3 tubes in the "Tube Count" register. The operator then taps the X/Y positioner joystick 1016 in the direction of the next tubes to be cleaned. The system 100 will automatically senses tubes via sensors 150, described in detail above, and advance the number of "Moves" indicated on the screen. The operator then repeats pressing the tractor forward button 1018 and reverse button 1020. 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 in
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 joystick 1016 to the right, and the controller will automatically move to the right three sensed holes. The operator then presses the tractor forward button 1018 to move the lances 101 into the aligned set of three tubes to be cleaned, followed by pressing the reverse button 1020 to withdraw the lances. The operator then taps the joystick 1016 again 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 joystick 1016 up or down to move to the next row and the process sequence is then repeated.
The information processed by controller 1000, 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 controller 1000 to 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 apparatus 1200 incorporating an autostroke functionality for each lance driven by the drive apparatus is shown in
Fastened to the front wall 1208 is an exit hose guide manifold 1214. Fastened to the rear wall 1210 below the carry handle 1212 is a hose entrance guide manifold 1216. Each of these manifolds 1214 and 1216 includes a set of hose guide collets 1218 for guiding one to three flexible lance hoses 167 (shown in
A motor side view of the apparatus 1200 is shown in
In this exemplary embodiment 1200, the inner vertical support wall 1220 carries a pair of pneumatic drive motors 1222 and 1224 mounted such that their drive shafts 1226 and 1228 protrude laterally through the support wall 1220 into the second portion, or belt cavity 1221, between the inner vertical wall 1220 and an outer vertical lower support wall 1230, shown in
On the belt side view shown in
The upper outer support wall 1240 carries a set of electrical connectors 1243 for 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 lights 1245 to indicate the status of each of these elements during drive apparatus operation.
A perspective view of the apparatus 1200 with the upper and lower outer vertical support walls 1240 and 1230 removed is shown in
Each of the drive shafts 1226 and 1228 may extend fully through the splined drive rollers 1246 or the drive motors 1222 and 1224 may each be fitted with a stub drive shaft which fits into a bearing within the proximal end of each of the splined drive rollers 1246. A separate bearing supported drive shaft 1226 or 1228 extends out of the distal end of each drive roller 1246 and is fastened to the support wall 1230 via cone point set screws. In such an alternative, the drive rollers 1246 become part of the drive shafts 1226 and 1228.
Spaced between the two splined drive rollers 1246 is a set of four cylindrical guide rollers 1248 that are supported by the lower outer support wall 1230 via a vertical plate 1250 and a pair of rectangular vertical spacer blocks 1252 that are through bolted to both the lower outer support wall 1230 and inner vertical wall 1220 through the vertical plate 1250 via bolts 1254. While the bolts 1254 pass through the vertical plate 1250, their distal ends extend further through, and are threaded into holes through the inner vertical wall 1220.
Tension on the endless belt 1242 is preferably provided by a tensioner roller 1258 between the spacer blocks 1252 that is supported from the inner vertical plate 1250 on an eccentric shaft 1260, and accessed through an opening 1262 in the inner vertical wall 1220, shown in
To replace the belt 1242, the four bolts 1254 are loosened and screws holding the outer lower wall 1230 to the front and rear walls 1208 and 1210 are removed. The cone point set screws engaging a V groove (not shown) in each of the shafts 1226 and 1228 are then removed. The assembled structure including the vertical plate 1250, spacer blocks 1252, belt 1242, drive rollers 1246, and guide rollers 1248 can then be removed as a unit by sliding the drive rollers 1246 off of the keyed shafts 1226 and 1228.
Each of the splined drive rollers 1246 preferably 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 belt 1242. 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 belt 1242 is 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 belt 1242 is 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 belt 1242 in the belt cavity is a lance hose clamp assembly 1244 including an idler roller assembly 1270. This exemplary clamp assembly 1244 includes a multi-cylinder frame 1272 fastened to the top plate 1204 of the housing 1202. The multi-cylinder frame 1272 carries two or three single acting pneumatic cylinders with pistons 1274 (shown in
One set of idler rollers 1280 is made up of three independent spool shaped bearing supported rollers 1282 shown in the sectional view through the apparatus 1200 shown in
The printed circuit board 1285 fastened to the underside surface of the upper support block 1276 carries 12 hall effect sensors 1300, 1302, and 1304 each arranged adjacent one of the rims 1283. As each roller 1282 rotates, for example, by 15 degrees, one of the magnets passes beneath its adjacent sensor 1300, 1302, or 1304 on the pcb 1285 and 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 apparatus 1200.
Each idler roller set 1280 is carried on a stationary axle 1290 fastened between the idler frame rails 1278. Only one idler roller set 1280 needs to have separate rollers 1282. The other 5 idler roller sets 1280 each 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 apparatus 1200 and keep the flexible lances each in desired contact with the endless belt 1242 during transit. Preferably the idler rollers 1280 and the individual rollers 1282 are 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 apparatus 1200. This latter configuration is preferred in order to accommodate several different lance hose diameters in the drive apparatus 1200.
In use, the drive apparatus 1200 may 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 manifold 1216 and beneath the center groove of the idler rollers 1280. When two lances are to be driven, the inner and outer passages through collets 1218 would be used. If three lances are to be driven, one would be fed through each collet 1218 and corresponding groove of each idler roller 1280.
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 rollers 1248 are shown as being smooth cylindrical rollers. They may alternatively be splined rollers similar to the drive rollers 1246.
One of the splined belt drive motors, motor 1222 in the illustrated embodiment 1200, is configured with a differential hall effect sensor 1289 to monitor speed and direction of rotation of the drive motor 1222, and hence lance travel along the belt 1242 through the drive apparatus 1200. A separate plan view of drive motor 1222 is shown in
By comparing the position of the lance hoses, i.e. distance traveled as sensed from the follower roller set sensors 1300, 1302, and 1304, for each of the lance hoses, with the belt drive motor speed and direction sensed distance from the signal output of sensor 1289, 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 rollers 1280.
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 motor 1222 instigating 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 apparatus 1200 preferably includes the comparator circuitry to compare the signals from each of the sensors 1300, 1302, and 1304 with the signal from the drive motor sensor 1289. The drive apparatus 1200 may also include a comparator that compares the signals between each of the sensors 1300, 1302 and 1304, 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 belt 1242. Alternatively the comparator circuitry may be handled via microprocessor in a system controller such as hand held controller 1000, separate from the apparatus 1200. In either case, an exemplary signal processing circuit is shown, in simplified block diagram form in
A simplified functional block diagram 1350 for autostroke control for the apparatus 1200 is shown in
The emergency dump signal actuation function of controller 1400 simply sends a signal to the valve driver board MCU in the tumble box 110 if the controller 1400 receives a signal through the comparators 1360 that exceeds a second threshold from any one of sensors 1300, 1302 or 1304. This second threshold is indicative of a reversal of count direction from the sensors 1300, 1302, or 1304 or an excessive rate of lance speed. If any one lance hose reverses direction while the drive motor sensor 1258 is 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 box 110 to immediately divert high pressure cleaning fluid pressure to atmosphere by de-energizing the dump valve. Utilizing the follower roller position sensors 1300, 1302, and 1304 for 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 apparatus 100 or 1200.
Operational control of the apparatus 1200, basically called a smart tractor, begins in operation 900, when a feed forward operation is selected by the operator on a cleaning system control box 108. This control box 108 may be floor mounted or may be the hand-held controller 1000, described above with reference to
Assuming the Drive button 1018 has been pressed, forward operation 902 energizes the drive motors 1222 and 1224 causing the endless belt 1242 to pull 1, 2 or 3 lances along the pathway between inlet manifold 1214 and outlet manifold 1216 through the apparatus 1200. As the lances move along the endless belt 1242, their movement causes the follower rollers 1282 to rotate, sending signals, picked up by sensors 1300, 1302 and 1304, to comparators 1360. At the same time, sensor 1289 on motor 1222 sends a similar signal to each of the comparators 1360.
Operation 906 receives linear lance position information from sensors 1300, 1302, and 1304 via the circuit board 1285 for each lance. Comparator operation 906 also receives belt position information from the sensor 1289 on the drive motor 1222. In operation 906, 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 operation 908 where 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 operation 902 and 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 operation 910, shown in detail in
An autostroke routine 910 begins in operation 912. Control then transfers to reset operation 914 where the lance to motor difference for each lance is set to zero and an incrementing counter is set to zero. Control then transfers to operation 916 where the increment counter is advanced by 1. Control then transfers to operation 918 where drive apparatus 1200 is signaled to drive backward for N increments. Control then transfers to operation 920, where the drive apparatus 1200 is signaled to drive forward N+1 increments. Control then transfers to query operation 922.
Query operation 922 asks whether the counter value is greater than or equal to 10. If the answer is no, control transfers back to operation 916 where the counter is incremented again and the process operations 918, 920 and 922 are repeated. If the answer in query operation 922 is yes, the counter is greater than or equal to 10, control transfers to query operation 924 which 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 operation 926.
In query operation 926, the question is asked whether the apparatus 1200 feed rate is at a minimum. If the answer is yes, control transfers to stop operation 928. 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 operation 926, if the answer is no, feed rate is not yet at minimum, control transfers to operation 930.
In operation 930, the tractor feed rate of apparatus 1200 is reduced. Control then transfers back to operation 914 where the lance to drive position mismatch is set to zero and the incrementing counter are set to zero, and the iterative process of operations 916 through 924 is repeated.
On the other hand, if in query operation 924, 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 operation 902, where normal tractor drive forward operation is resumed, until the drive button in operation 904 is released, which stops tractor forward feed in operation 911.
A process flow diagram 950 of the controller 1400 is shown in
In query operation 956, the query is made whether clamp pressure is at or above a predetermined maximum pressure. If the answer is yes, control transfers to operation 960 where 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 operation 956 is no, pressure is not at maximum, control transfers to operation 958, where clamp pressure is increased by a predetermined amount, such as 2 psi. Control then transfers back to query operation 954 and operations 954, through 956 are repeated until the mismatch determined in operation 954 is less than or equal to 1. Control then transfers back to operation 902 described above.
Controller 1400 may also be configured via process 950 to automatically synchronize position of all lance hoses 167 being driven by the drive 1200 and maintain synchronization between these lance hoses 167. 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 controller 1400 continues to drive apparatus 1200 until all three lances 167 are at full insertion as sensed by contact with the hose stops. When the operator instructs the controller to reverse direction, the lances 167 will begin withdrawal in synchronization. During reverse direction of the lance hoses 167 if a mismatch between the sensed positions of each lance hose is again sensed, less than the maximum, which would indicate an obstruction, the controller 1400 continues to withdraw the lance hoses 167 until all of the hose crimps are detected. Controller 1400 signals the drive motors to stop, with all lance hoses 167 resynchronized in the fully withdrawn position. The drive 1200 may then be repositioned to clean another set of tubes.
The tumble box 110 communicates with a control box 108 which may be floor mounted as illustrated in
This haptic feedback motor vibrational signal is a safety feature to alert the operator to an unexpected event and/or potential unsafe condition. These events may include a sensed obstruction in the tube being cleaned, sensed end of lance travel indicated by the lance stop sensors or a mismatch between lances as determined from the lance position sensors. These lance position sensors are described in more detail below. Operation of the haptic feedback vibrational signal may be especially helpful and important to the operator in extremely noisy conditions, when visual observation of lance drive operation is obscured, and/or as a warning when the operator is not paying sufficient attention to the operation of the system.
The tractor 1200 carries a belt drive sensor 1289 and three lance position sensors 128 as above described, and at the rear of the tractor 1200 a hose stop sensor 162 and at the front end a set of hose crimp sensors 140. 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 hoses 167), or a physical stopper such as a conventional "football" fastened to the lance hose 167 that signifies full insertion of the lance hose through the target heat exchanger tubes. Each of these sensors 140 or 162 may each optionally be a physical switch.
This alternative apparatus 2000, shown in
Many variations are envisioned as within the scope of the present disclosure. For example, all processing circuit components of the control box 108 may be physically housed therein. Alternatively, the components within the control box 108 could be integrated into the drive apparatus 102 or into the housing of the drive apparatus 1200. In the case of drive apparatus 1200, the control circuitry may be housed in the separate hand-held controller 1000 described 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 apparatus 1200. In addition, the apparatus 1200 may 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 manifolds 1214 and 1216 or on the side of the housing 1202 as shown in
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 controller 1000 may be shaped differently than as is shown in
The apparatus 100 described above includes an X/Y positioner frame 104. 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 sheet 102 and having an extensible arm that radially extends from the rotator, and carries the smart tractor drive apparatus 102 along the arm could also be utilized in accordance with the present disclosure. In such an alternative, the controller 1000 would be essentially the same, except that the joystick 1016 right 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 apparatus 102 along 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.
A separate perspective view of the lance position assembly 2102 mounted on the rear wall 1210 of the tractor drive 2100 is shown in
Each multipole ring portion 2112 has a radially arranged series of alternating polarity magnetic poles arranged such that the outer periphery of the multipole ring has alternating north and south poles therearound. Thus, as the ring portion rotates with the knurled polymeric roller portion 2110, a magnetic sensor placed adjacent the ring portion will sense the transitions between the alternating polarities. In one exemplary embodiment there are 24 magnets within the ring portion. This translates to .0654 inches of lance travel per count/transition.
Each of the transitions is sensed by a detector coil in the magnetic sensor module 2114 and the sensed transitions are sent via cable 2115 through the drive 2100 ultimately to the controller 1000 for processing in the same manner as previously described above. The magnetic sensor module 2114 is an environmentally sealed and encapsulated unit that is replaceable as needed by separation of one of the side plates 2108 bolted to the rear wall 1210 of the tractor drive 2100.
Mounted directly above the sensor rollers 2104 is an array of independently suspended pneumatically loaded idler rollers 2118. Each idler roller 2118 is carried in a pneumatically pressurized yoke 2120. Each yoke 2120 has a piston stem 2122 carried within piston cap 2124 fastened to the end plate 1210. The piston cap 2124 is essentially a solid block body with a common cavity communicating with three parallel bores each supporting one of the piston stems 2122 therein. A clamp pressure system fitting 2130 supplies pneumatic pressure from the idler clamp system circuit through the common cavity and each of the piston stems 2122 to the idler rollers 2118 to maintain each of the idler rollers 2118 firmly in contact with each lance hose 167 passing into and through the tractor drive 2100 such that each hose 167 is in constant engagement with its sensor roller 2104. In this way, the actual lance travel position for each lance 101 is monitored and tracked for comparison to each other lance. The individual lance positions are then compared to each other to determine various parameters such as lance to lance position mismatch, total lance travel through the heat exchanger tube, occurrence of any blockage or slippage, etc. or excessive resistance to nozzle/hose travel during operation. A rapid reversal event is also sensed which would indicate an unsafe condition. The individual lance positions are also used for feed rate determination, controlling the autostroke function and tube blockage detection.
Each idler roller portion 2118 is preferably knurled or roughened to ensure precise contact with the lance hose 167. During drive operation, the lance hoses 167 may become slippery. The knurling helps ensure that the lance position sensing remains accurate during other than optimal operational conditions.
An idler roller yoke guide plate 2126 fastened to the piston cap 2124 guides vertical extension and retraction of the idler rollers 2118 and has three guide notches or cutouts for guiding the flexible lances 101 as they are inserted into and through the tractor drive 2100. This guide plate 2126 also ensures that the flexible lances remain aligned with their respective idler rollers 2118 when less that 3 lances are driven by the tractor drive 2100.
The crimp and stop sensor module 2144 senses the presence or absence of metal present within any one of the three bores therethrough. The distal end of the flexible lance hose 167 is fitted with a threaded fitting to which a nozzle 105 is attached before the flexible lance 101 is inserted into the tractor drive apparatus 2100. The rear half inch or so of this threaded fitting is a metal crimp to retain the end of the flexible lance hose 167 to the threaded fitting.
When one, two or three flexible lances 101 are threaded into and through the tractor drive assembly 2100, the removable hose crimp and stop sensor module 2144 must already be installed in its complementary slot 2145. However, the collet 2142 must be temporarily removed to permit passage of the end of the flexible lance carrying a nozzle (not shown). Once the lance hoses are inserted through the assembly 2100 the collet 2142 is installed to prevent inadvertent rearward passage of the crimp and nozzle 105 of a lance 101 back through the guide tubes in the event of a catastrophic lance failure.
Each flexible lance 101 is fitted with a unique stop element 2152 in accordance with this disclosure to indicate full travel of the lance 101 through the target tube, e.g. tube 202. A separate perspective view of one stop element 2152 is shown in
Each of the stop elements 2152 is made in two clamshell identical halves that are fastened together via two threaded fasteners through the cylindrical stop portion 2154, and grips the lance hose 167 therebetween. The narrow shoulder extension portion 2156 has an outer diameter sized to fit into the rear stop block 2150 and through one of the bores though stop sensor module 2144. The narrow shoulder portion 2156 also preferably has an outer diameter matching that of the crimp on the flexible lance hose end fitting 105 and is made of metal.
A hose crimp and stop sensor module 2144 may be interchanged between installation in the stop block 2150 or the front guide tube assembly 2140 as these sensor modules are identical. Each module 2144 is preferably sized to accommodate all anticipated lance hoses, e.g., from 3/2 to 8/4 lance hoses. This is limited by the through hole diameter for the largest size and smallest practical lance size for which the tractor drive is rated.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.