2201Q4JE-MY-C9-N_2018.01.
Chapter 5 Maintenance and Inspection
Compound 2-stage Screw Compressor 4032**C
5.3 Compressor Disassembly Preparation
5-10
5.3.3
Refrigerant Gas Recovery
At the time the compressor operation is stopped, the pressure inside the compressor is still high. As
such, it is necessary to drop the pressure down to the atmospheric pressure before starting the
disassembly process. To do this, there are the following methods for example.
Perform your recovery work in an appropriate manner considering site conditions, requirements of
regulatory laws and regulations.
■ Use the bypass valve to release the high pressure gas in the unit into the low pressure side.
■ If there is an adjacent compressor to which a permanent bypass line is connected from this
compressor, run the adjacent compressor to drop the internal pressure of this compressor through
the bypass line.
■ Operate the refrigerating system and close the supply source valve to turn the gas into liquid, and
recover the liquid at the receiver.
■ Use a refrigerant recovery machine to recover the liquid at the receiver.
In using either method, prepare a working flow sheet of the system beforehand. Check the valves to be
controlled during the recovery work, according to the method to be used, by comparing them with the
ones in the flow sheet, and clearly note the valves to be operated, other connected devices, and tubes
on the flow sheet.
Two flow sheets must be prepared: one at the foreman and the other for posting in the workplace.
In addition, prepare a work procedure document for the refrigerant recovery work to reflect the actual
conditions of the workplace, and sufficiently share the work details among all the coworkers through
checking and confirmation before actually starting the work.
The gas mask and other protective gears required at each stage of refrigerant recovery work must be
prepared before starting the work.
Before the work, be sure to check and communicate the work details and procedure
among all coworkers, and carry out hazard prediction activities based on the
information shared. Neglecting to do this will increase the risk of on-the-job accidents
and injuries to a considerable level.
All the valves that have been opened or closed during the work must be prevented
from accidental operation through proper lock-out and tag-out procedures.
