【Q&A Question 048】2016.06.07

First, slowly open the oil flushing valve to flush oil into the spare filter. Open the return oil valve; once oil is visible in the return oil sight glass, close both the oil flushing valve and the return oil valve. Open the valve of the spare upper filter, and while closing the oil valve of the filter that needs to be switched out, slowly open the oil valve of the spare lower filter. Finally, close the upstream valve of the filter that needs to be switched out. Note: The oil filling valve should not be opened too quickly (lubricating oil), to prevent a sudden drop in main pipe pressure that could lead to cascading effects.

First, open the connection valve to fill the spare filter with oil, then turn the steering valve. If the filter is not fully filled with oil, it may cause a temporary drop in oil pressure; the auxiliary oil pump will start automatically, and in severe cases this can lead to the machine shutting down

Before making the switch, inspect the spare filter, close the drain valve, open the vent valve, and slowly open the oil filling connection valve to fill the spare filter with oil at a low flow rate. Pay close attention to the sight glass of the exhaust valve. When there is flow passing through the sight glass, close the vent valve and the oil filling connection valve, and slowly turn the switch handle to the standby filter, paying attention to changes in oil pressure and the proper positioning of the valves. Poor switching can easily lead to low oil pressure and subsequent shutdown of the equipment

　　I. Preparatory work before shutting down the machine
(1) Activate the compressor auxiliary systems:
1. Activate the startup purging system.
2. Use nitrogen to purge the standby machine for airtightness checks.
3. Activate the cooling water system.
4. Activate the compressor discharge system.
5. Activate the lubricating oil system.
6. Activate the isolation nitrogen system.
7. Activate the oil injection system.
(2) Perform shaft rotation.
(3) Open all return valves between stages, open the outlet valves, and close all vent and drainage valves; introduce the process medium.
(4) Ensure power is available, start the standby machine, and maintain close communication between operators on site.
(5) Check the operation of the standby machine for any leaks, and verify that instruments are showing normal readings.

II. Starting the standby machine
1. Start the standby machine under no-load conditions.
2. Check that all current readings are normal.

III. Shutting down the machine
1. Increase the load on the standby machine to 20%, while reducing the load on the operating machine by 20%.
2. Check whether the outlet flow rate, pressure, and inter-stage cooling temperatures are normal.
3. If everything is normal, increase the load on the standby machine to 50%, while reducing the load on the operating machine by 50%.
4. Check again the outlet flow rate, pressures at each stage, and inter-stage cooling temperatures.
5. Gradually increase the load on the standby machine to 100%, while reducing the load on the operating machine to 0%.
6. Confirm that the outlet flow rate, pressures at each stage, cooling temperatures, and motor current are all normal.
7. Stop the main motor of the operating machine.
8. Adjust the flow rate and pressure of the operating machine to normal levels.
9. Set the return valves at each stage to automatic mode.
10. Activate the machine’s interlock system.

IV. Precautions
Pay close attention throughout the process:
1. Total flow rate: It should not fluctuate by more than 5% of the total amount, to avoid large fluctuations that could damage equipment and pipelines and affect reaction processes. 2. Pressure: The pressure must not rise too quickly or exceed the limit; it is strictly prohibited for the safety valve to activate. 3. After each adjustment of the load, wait for a while until the process system stabilizes before making the next adjustment.

Open the connection valve to fill the spare filter with oil; loosen the nut that holds the switching handle in place, and switch the filter. A poor switching operation may cause a chain reaction in the oil station

Open the connection valve between the filters to fill the spare filter, and vent the gas from the top until no oil is left. Turn the three-way valve between the two filters to switch the filter to spare mode, then close the connection valve. During this switching process, the connection valve should remain open to prevent the three-way valve from getting stuck and causing a stop in the supply of lubricating oil. An improper switch operation can cause a temporary interruption in the lubricant flow, and may even lead to a shutdown.

First, open the oil refill valve of the spare filter to fill it with oil. Then simply push the filter three-way valve to the side of the spare filter. Poor switching can lead to low oil pressure, causing the unit to shut down via interlock

Before making the switch, inspect the spare filter, close the drain valve, open the vent valve, slowly open the oil filling connection valve, and slowly fill the spare filter with oil, paying close attention to the sight glass of the exhaust valve. When there is flow passing through the sight glass, close the vent valve and the oil filling connection valve, and slowly turn the switch handle to the standby filter, paying attention to changes in oil pressure and the proper positioning of the valves. Poor switching can easily lead to low oil pressure and subsequent shutdown of the equipment

Before making the switch, inspect the spare filter, close the drain valve, open the vent valve, and slowly open the oil filling connection valve to fill the spare filter with oil at a low flow rate. Pay close attention to the sight glass of the exhaust valve. When there is flow passing through the sight glass, close the vent valve and the oil filling connection valve, then slowly turn the switch handle to the spare filter. Pay attention to changes in oil pressure; if the valve is not positioned correctly, it may cause the auxiliary oil pump to stop operating