Segmented pressure maintenance can effectively detect the system's gas tightness, ensuring smooth experimental operations. The principle involves evacuating the system to a vacuum, then closing each segment valve to isolate the tubing between the valves. After maintaining pressure for a designated period, the valves are sequentially opened, allowing the pressurized segments to connect to the pressure sensor's measurement range. By observing the pressure changes when each segment is connected, it is possible to determine which segment is leaking. This targeted approach allows for maintenance of the specific valve causing the leak, thereby resolving the instrument's gas leakage issue.
1）Ensure the reactor and the system are dry, and install the reactor onto the system;
2）Turn on the μGAS1000 power switch, wait for 1-2 minutes, then open the μGAS1000 software. Click on the “Start Experiment” interface, select the μGAS1000 instrument serial port in the upper right corner 
. After that, click the icon in the upper right corner of the software interface 
. If the icon turns green and the “Device Real-Time Status Information” shows values, the connection is successful; if there are no values, troubleshoot and restart the instrument and software;
3）Click the “Self-Check” icon in the software interface and wait for the instrument to complete the self-check;
4）Confirm the valve status: F valve (vacuum), D valve (system circulation), C1, C2 valves (dual circulation), E and B valves (system circulation).
2.1
System Evacuation
In the software, click “Vacuum Pump ON”, rotate the D valve to the “Vacuum” position, and wait for the system pressure to stabilize to complete the internal evacuation.
2.2
Vacuum Cup Evacuation
1）Rotate the E valve to “Gas Storage Circulation”, wait 10 seconds, then turn it back to “System Circulation”. Rotate the E and F valves away from the “Vent” position 180° for 3-5 turns, then sequentially rotate the B, C1, C2, and D valves 360° in one direction for 5 turns each; keep the D valve in vacuum state for 5 minutes;
2）After completion, rotate the D valve to “System Circulation” and close the vacuum pump in the software. At this point, the valves should be in the following states: F valve (vacuum), D valve (system circulation), C1, C2 valves (dual circulation), E and B valves (system circulation).
▷ Select “Load Gas” mode, set the number of gas loading cycles to 4-5;
▷ Click “Run/Stop” to start the operation, and wait for the gas loading process to finish before stopping the operation (Note: μGAS1000 may experience external environmental interference on the pressure sensor under low vacuum, causing significant pressure fluctuations. At this point, the instrument is not leaking, but it affects the judgment of segmented pressure maintenance data. Therefore, during segmented pressure maintenance, it is necessary to load a certain amount of carrier gas into the system to achieve a pressure of around 5 kPa).
1）Rotate the D valve to the horizontal right, C1 valve to the lower left, C2 valve to the upper left, E valve to the upper left, and B valve to the upper right. Note the initial pressure value displayed on the system screen, and maintain this state for at least 12 hours (Note: All valves should be oriented with the small end pointing; all valves should be rotated along the shortest path);
2）After pressure maintenance, observe if the system display pressure has increased. If it rises more than 1.2 kPa, it indicates a leak between the D valve and B valve, requiring re-maintenance of the B and D valves. If it still leaks after maintenance, open the instrument's back cover to maintain the pressure sensor plug located between the B and D valves inside the instrument;
3）If the system pressure does not increase more than 1.2 kPa after pressure maintenance, you can rotate the D valve to system circulation and observe the pressure change compared to the initial pressure. If it rises more than 1.2 kPa, it indicates a leak in the C1 valve;
4）If the system pressure does not increase more than 1.2 kPa when the D valve is set to system circulation, rotate the C1 valve to line circulation and observe the pressure change compared to the initial pressure. If it rises more than 1.2 kPa, it indicates a leak in the C2 valve;
5）If the system pressure does not increase more than 1.2 kPa when the C1 valve is set to line circulation, rotate the C2 valve to line circulation and observe the pressure change compared to the initial pressure. If it rises more than 1.2 kPa, it indicates a leak in the E valve;
6）If the system pressure does not increase more than 1.2 kPa when the C2 valve is set to line circulation, sequentially rotate the B, E, and C1 valves to system circulation. If the pressure rises more than 1.2 kPa at this point, it indicates a leak in the reactor;
7）If all valves are set to system circulation and the system pressure does not increase more than 1.2 kPa compared to the initial pressure, then the system's gas tightness is intact (when identifying leaking valves through segmented pressure maintenance, only targeted maintenance of the corresponding valves is required. If a leak is identified in the reactor, the vacuum seal at the reactor's ball mill joint should be maintained, and check whether the reactor's optical window is installed correctly and if the sealing ring has any aging or damage. If the reactor has a sampling port, the internal sampling pad can be replaced).
