Method and apparatus for delivering a tool to the interior of a heat exchange tube
View Patent ↗A delivery system for remotely driving an eddy current probe through the tubing of a heat exchanger. The system uses a flexible shaft and air pressure to move an inspection probe through the heat exchanger tubes. The flexible shaft initially drives the probe through a sealed conduit to deliver the probe to the tube end at which point a seal on the shaft near the probe head contacts the tube inner surface allowing a buildup of air pressure behind the seal, thus driving the probe through the tube.
1. A tool delivery system for remotely transporting a tool to and through a heat transfer tube of a heat exchanger having a plenum in fluid communication with an interior of the heat transfer tube through a first tube end and an access port for accessing the plenum, the tool delivery system comprising:
a sealable delivery conduit sized to extend from a first location outside the plenum, through the access port to the first tube end;
a flexible shaft for pushing the tool through the delivery conduit into the heat transfer tube;
a first seal supported within the vicinity of a forward portion of the flexible shaft and forming a substantially fluid tight, slidable seal between the interior of the heat transfer tube and the flexible shaft when the flexible shaft is inserted a given distance into the heat transfer tube;
a second substantially stationary seal on a portion of the delivery conduit that is to be positioned outside the plenum, the second seal being supported in a manner to form a substantially fluid tight seal between the flexible shaft and an interior of the delivery conduit while enabling the flexible shaft to slide there through; and
a fluid inlet on the delivery conduit in fluid communication with the interior of the delivery conduit, between the flexible shaft and an interior wall of the delivery conduit, downstream of the second seal between the second seal and the first tube end.
2. The tool delivery system of claim 1 including a third seal supported at an end of the delivery conduit that is configured to interface with the first tube end, the third seal being structured to form a substantially fluid tight seal between the first tube end and the delivery conduit.
3. The tool delivery system of claim 1 wherein the flexible shaft is sufficiently rigid to push the tool forward until the first seal seats within the heat transfer tube to form the substantially tight seal between the flexible shaft and the interior of the heat transfer tube.
4. The tool deliver system of claim 1 including a fourth seal upstream of the second seal, the fourth seal structured to provide a substantially fluid tight seal between the flexible shaft and the delivery conduit while enabling the flexible shaft to slide there through with the space within the interior of the delivery conduit between the second seal and the fourth seal forming a chamber, including a port through a wall of the chamber.
5. The tool delivery system of claim 1 wherein the first and second seals are configured so that the tool and the flexible shaft can exit the delivery conduit.
6. The tool delivery system of claim 1 wherein the delivery tube is supported in sealed fluid communication with the first tube end with a robotic arm.
7. The tool delivery system of claim 1 wherein the first seal includes a plurality of circumferential outer segments that overlap a plurality of circumferential inner segments with the outer and inner segments being biased in an outwardly direction.
8. The tool delivery system of claim 7 including a fluid path having an inlet on an upstream side of the first seal in fluid communication with an inward surface of the inner segments.
9. The tool delivery system of claim 1 wherein the first seal includes circumferentially alternating seal pads and resilient elastomeric foam seal segments wherein the elastomeric foam seal segments conform to both the seal pads and an interior wall of the heat transfer tube to create a substantially fluid tight, slidable seal between the interior wall and the tool.