• Topic ID: id_15460516
  • Version: 3.0
  • Date: Jun 15, 2020 11:02:52 PM

Heat Exchanger Replacement

Prerequisites

Overview

In order to replace the Heat Exchanger unit:

  • Lockout system

  • Remove heat exchanger pump

  • Replace heat exchanger

  • Re-install heat exchanger pump

  • Reconnect heat exchanger

1 Heat Exchanger Removal

Procedure

    • warning
    • Potential for Shock.
    • Voltage may be present.
    • Use proper lockout/tagout procedures before replacing components.
  1. Remove gantry covers.
  2. Turn OFF all 3 switches (120 VAC, AXIAL DRIVE ENABLE, and HVDC ENABLE, ) on the Service Switch Panel.
  3. Remove the right front gantry cover mounting bracket. See Figure 1.

    Figure 1. Right Front Gantry Cover Mounting Bracket

  4. Remove the filter by following the Heat Exchange Filter Replacement procedure.
  5. Remove the Heat Exchange Pump by following the Heat Exchanger Pump Replacement procedure.
  6. Disconnect Power Interface board connectors J1, J2, and J7. Reference Figure 2

    Figure 2. Power Interface Connectors

  7. Rotate the gantry so that the tube is at approximately the 3 o'clock position, such that you can reach the lower mounting bolts for the heat exchanger. See Figure 3.

    Figure 3. Lower Heat Exchange Mounting Bolt Location

  8. Remove the two lower heat exchange mounting bolts.
  9. Remove the safety locking mechanism then disconnect the heat exchanger from the X-Ray tube's cooling hose at the quick disconnect. See Figure 4

    Figure 4. Safety Mechanism

  10. Rotate the gantry so that the tube is between 3 and 4 o'clock, with the heat exchanger lifting point at approximately 1 o'clock. Remove any slack in the chain. See Figure 5.

    Figure 5. Gantry Position

  11. Lock the gantry in position, using the rotational lock. Ensure that gantry rotation is locked by attempting to rotate the gantry by hand.
  12. Assemble the gantry post / boom / hoist and connect the hook to the lifting point on the heat exchanger. See Figure 6.

    Figure 6. Assemble Hoist

    • warning
    • CRUSH HAZARD.
    • When the upper mounting bolts are removed, the heat exchanger unit may shift.
    • Be sure that your hands are clear.
  13. Remove the two upper mounting bolts.
    Notice Image
    • notice
    • Be careful in this area when removing and installing the heat exchanger.
    Notice Image
    • notice
    • Use the hoist to adjust the heat exchanger to clear the laser light bracket and avoid obstacles like the collimator cam motor. Also be sure NOT to cut any wires near the tube. See Figure 7.
  14. Using the hoist to control the height of the heat exchanger, carefully swing the heat exchanger free from the gantry.

    Figure 7. Pinch Points

2 Heat Exchanger Installation

Procedure

  1. Remove the four (4) heat exchanger filter screws and filter from the new heat exchanger to aid in the installation.
  2. Using hoist, swing new heat exchanger into place on the gantry. Be careful in the collimator motor area where it is possible to cut wires and damage other equipment. See Pinch Points Figure 7.
  3. Start the upper heat exchanger mounting bolts by hand. Use the hoist to adjust height if necessary. You will also need to use some force to get the heat exchanger to align with the mounting holes on the gantry's rotating base.
  4. Tuck the rubber shield underneath the heat exchanger under the bracket on the rotating base.

    Figure 8. Rubber Shield Tucked

  5. Apply “preload” torque to the M12 mounting bolts:
  6. Disconnect the hoist from the HX.
  7. Apply final torque to the M12 mounting bolts:
  8. Make the following HX connections:
    1. J1, J2, J7 on Power Interface board.
    2. X-Ray tube to HX hose.
  9. Secure the quick disconnect safety locking mechanism. The torque spec. for the quick disconnect safety mechanism is 9.9 N-m (7.3 lb-ft, 88 lb-in, 101 kg-cm), however, if the locking mechanism rotates in relation to the quick disconnect, tighten slowly until it does not do so.
    note: Do not severely overtighten the M6 bolts. Doing so can cause the quick disconnects to leak.
  10. Disengage rotational lock.
  11. Rotate the gantry so the tube is at the 4 o'clock position.
  12. Install heat exchange pump. See Heat Exchanger Pump Replacement procedure for installation directions.
  13. Make sure you reattach any tie wraps that you removed.
  14. Reattach Gantry Right Front cover mounting bracket. See Figure 1.
  15. Install filter by following the Heat Exchange Filter Replacement installation instructions.