• Discovery MR750 3.0T System Service Methods
  • 5690009-2EN Revision 4
  • Object ID: 00000018WIA30E04510GYZ
  • Topic ID: id_2004505 Version: 7.0
  • Date: Feb 24, 2021 12:57:54 AM

Inspecting the cryocooler adsorber

Prerequisites

Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1-5 minutes -
Replacement parts
ItemQuantityPart numberManufacturer
Adsorber (see Magnet Manual)1--
Safety

Before working in any GE Healthcare MR suite or performing any GE Healthcare service procedure, you must:

  • Have read and understood all hazard conditions and safety requirements in the latest revision of the GE Healthcare MR Service Safety Manual (5452735).
  • Have successfully completed all relevant GE Healthcare Environmental Health and Safety (EHS) courses (or for non-GE employees, equivalent workplace training courses).
  • Comply with all site-specific training and workplace safety requirements.

If you have any safety concerns at any time, do not begin work or immediately stop work and move to a safe location. Immediately contact your supervisor or site safety officer for instructions on how to proceed.

Procedure

  1. Check the hour meter on the front of the compressor. The frequency of adsorber replacement depends on the compressor model:
    • Sumitomo CSW-71 Compressor 4 Kelvin System (Zero Boil-Off): Adsorber must be replaced every 20,000 hours.
    • Sumitomo F-50 Compressor (Zero Boil-Off): Adsorber must be replaced every 30,000 hours.
    • Sumitomo F-70 Compressor (Zero Boil-Off): Adsorber must be replaced every 30,000 hours.
  2. Review records to verify the adsorber was replaced on schedule.
    If the adsorber should be replaced, order a replacement adsorber and schedule an immediate adsorber replacement. Refer to the Sumitomo service documentation for details on adsorber replacement.

    Note: The replacement adsorber is compatible with both Sumitomo compressors (CSW-71 and F-50).
  3. Calculate when the next replacement is due, based on the compressor model.
  4. Record the calculated adsorber replacement date in the Site Log and on the PM Schedule. Record the next replacement date on an external tag on the compressor.
  5. Check and record the compressor dynamic pressure on the supply pressure gauge located on the front of the compressor:
    • Sumitomo CSW-71: Compressor dynamic pressure should be between 2.10 MPa and 2.30 MPa.
    • Sumitomo F-50: Compressor dynamic pressure should be between 1.90 MPa and 2.20 MPa.
    • Sumitomo F-70: Compressor dynamic pressure should be between 1.79 MPa and 2.30 MPa.

    If pressure is not as specified, refer to the Sumitomo service documentation. If it is necessary to recharge the compressor, that recharge must be done with 99.999% pure helium gas.

    Note: The supply pressure gauge displays high-side dynamic pressure when the compressor is turned on and static pressure when the compressor is turned off.
  6. Turn the compressor OFF and allow the static gas pressure to equalize on the supply gauge located on the front of the compressor.
  7. Record the equalized pressure on PM Report and on the Cryostat Performance Log in the Site Log Book.
    Compressor static pressure should be between 1.60 MPa and 1.65 MPa for both the Sumitomo CSW-71 and Sumitomo F-50 compressors.

    Compressor static pressure should be between 1.34 MPa and 1.37 MPa for Sumitomo F-70compressors.

    If pressure is not as specified, refer to the Sumitomo service documentation. If it is necessary to recharge the compressor, that recharge must be done with 99.999% pure helium gas.

  8. Turn the compressor ON.