An apparatus for sensing an obstruction within a tube being cleaned and repetitively advancing and retracting a flexible high pressure fluid cleaning lance within the tube is disclosed. The method includes sensing a pneumatic supply pressure to a pneumatic lance drive motor at the motor during forward operation, sensing a pneumatic discharge pressure at the drive motor during forward operation, determining a difference between the pressures, comparing the difference to a predetermined difference threshold; reversing the drive motor direction for a predetermined time interval if the difference exceeds the threshold, and restoring forward operation after the predetermined time interval; and repeating the reversing and restoring operations until the difference no longer exceeds the predetermined difference threshold.

A tube cleaning system and method including a nozzle holder operable to secure nozzles in a nozzle arrangement, the nozzle arrangement corresponding to an arrangement of tubes of a tube bundle, and a nozzle positioning system operable to move the nozzle holder and nozzles secured therein, to cause the nozzles to engage a set of tubes of the tubes of the tube bundle, the nozzles configured to direct cleaning fluid into the set of tubes.

A frame apparatus for holding a flexible lance positioning mechanism adjacent to and spaced from a heat exchanger tube sheet includes an upper guide rail, a lower guide rail, a positioner rail supported from one of the upper and lower guide rails and guided by the other of the upper and lower guide rails, and a rail clamp assembly fastened to a portion of a tube sheet. This rail clamp assembly has a flat plate member fastened to the tube sheet, a base plate spaced from the flat plate by one or more threaded shafts, and one or more clamp fingers rotatably fastened to the base plate. Each clamp fingers is operable to rotate toward the base plate when the base plate is drawn against the flat plate or beam member by rotating the threaded shaft, thus drawing the rail securely to the flat plate of the clamp assembly.

A method and to a cleaning device for cleaning tubes of tube bundles, wherein at least one rotating cleaning lance is used. During the insertion of the cleaning lance, the insertion depth E of the cleaning lance is measured and is stored and documented in a storage and documentation device. The cleaning device has an XY displacement device, on which a support rail is arranged, which supports a cleaning apparatus.

A system and an apparatus for positioning a plurality of flexible cleaning lances includes a frame removably fastened parallel to a row of tubes in a tube sheet within a domed end of a heat exchanger. A chassis support member is mounted on the frame for movement in an X direction. A chassis having spaced apart parallel box rail members is movably mounted on the chassis support member for movement of the chassis in a Y direction. A rotary arm extends from the chassis, and a flexible lance guide hand fastened to a distal end of the rotary arm is configured to maintain a plurality of flexible lance guide tubes in parallel alignment with the row of tubes irrespective of an angle between the rotary arm and the frame. The system may include a lance drive and a snout connected between the lance drive and the positioning apparatus.

A method for preventing fouling of an operating heat exchanger is disclosed. A carrier liquid is provided to the heat exchanger. The carrier liquid contains a potential fouling agent. The potential fouling agent is entrained in the carrier liquid, dissolved in the carrier liquid, or a combination thereof. The potential fouling agent fouls the heat exchanger by condensation, crystallization, solidification, desublimation, reaction, deposition, or combinations thereof. A gas-injection device is provided on the inlet of the heat exchanger. A non-reactive gas is injected into the carrier liquid through the gas-injection device. The non-reactive gas will not foul the heat exchanger surface and will not condense into the carrier liquid. The non-reactive gas creates a disturbance by increasing flow velocity and creating a shear discontinuity, thereby breaking up crystallization and nucleation sites on the surface of the heat exchanger. In this manner, fouling of the operating heat exchanger is prevented.

A frame apparatus for holding a flexible lance positioning mechanism adjacent to and spaced from a heat exchanger tube sheet includes an upper guide rail, a lower guide rail, a positioner rail supported from one of the upper and lower guide rails and guided by the other of the upper and lower guide rails, and a rail clamp assembly fastened to a portion of a tube sheet. This rail clamp assembly has a flat plate member fastened to the tube sheet, a base plate spaced from the flat plate by one or more threaded shafts, and one or more clamp fingers rotatably fastened to the base plate. Each clamp fingers is operable to rotate toward the base plate when the base plate is drawn against the flat plate or beam member by rotating the threaded shaft, thus drawing the rail securely to the flat plate of the clamp assembly.

A flexible lance drive device is disclosed that has, in a compact housing, a drive motor between an inner and an outer wall, a linear array of pairs of driven upper and lower drive rollers outside the outer wall coupled to the drive motor via shafts extending through both of the inner and outer walls. Each driven roller is fastened to its shaft via a quick release device. A drive sprocket is fastened to each shaft outside the inner wall. The drive motor is coupled to each of the drive sprockets via a serpentine belt carried outside the inner wall. The lower driven rollers are rotatably carried by the inner and outer walls. The upper driven rollers are rotatably carried by a block positioned between the inner and outer walls and coupled to the lower driven rollers by a pair of parallel links releasably biased by a piston driven linkage.

A guide tube pitch adjustment apparatus for aligning distal ends of lance guide tubes in registry with tube openings in a heat exchanger tube sheet is disclosed. A guide tube pitch clamp assembly carried within and supported from a housing. The pitch clamp assembly has at least two V-blocks fastened to a threaded rod. One V-block is fastened to a portion of the threaded rod having right hand threads, and another V-block is fastened to another portion of the threaded rod having left hand threads. Each of the V-blocks supports a portion of one of the guide tubes, and a cross bar clamp within the housing is oriented to span across the V-blocks and adjustably hold the portions of the guide tubes in a spaced relationship such that spacing between the distal ends of adjacent guide tubes may be adjusted by rotation of the threaded rod.

A self-rotating tube cleaning nozzle assembly is disclosed that includes at least one debris exclusion feature. The nozzle assembly includes a main body defining an internal fluid passageway, a nozzle mounted to the main body, and a sleeve rotatably disposed about the main body. In one aspect, the sleeve having at least one discharge port in fluid communication with the main body internal fluid passageway for discharging a spray and rotating the sleeve about the main body. The debris exclusion feature is defined between the main body and the sleeve and includes a stepped portion on an exterior surface of the main body that faces and overlaps with a complementarily shaped stepped portion on an interior surface of the sleeve. The debris exclusion feature forms a tortuous pathway that eliminates or reduces contaminant ingress.