6.2 Long-Term Maintenance
6.2.1 20,000 Hour Maintenance
The maintenance procedures below must be completed by a certified technician. This can be done
onsite without removing the equipment or disturbing the optical setup. Contact an authorized service
representative to schedule maintenance.
Cryocooler
The GM cryocooler normally needs maintenance every 10,000 hours of operation. After extended use,
some of the bearings and bushings will wear down. Due to the variable speed compressor, which runs
at lower speeds under certain conditions, this maintenance interval is typically extended to 20,000
hours.
Other indicators of needing cryocooler maintenance include:
• System begins to have trouble cooling. The achievable base temperature drastically degrades.
• System begins to make a cogging or grinding noise in the cryocooler that persists continually.
Compressor Filter and Adsorber
The helium gas used in the compressor passes through two filters and is cleaned before exiting. The
first of these, the coalescing filter, uses fiber glass filter elements which coalesces any oil mist that is
present. The oil is collected and periodically drained to the compressor capsule. The second filter is a
charcoal adsorber. All the oil removed by the adsorber remains within it. As a result, the filter and
adsorber must be replaced after extended operation. This maintenance procedure is completed at the
same time as cryocooler 20,000 hour maintenance.
To Next Page
Loading...