Date of work:
24, Feb, 2025
Workers:
Kimura and Yasui
Abstract:
We pressurized OMC and OMMT atmospheric pressure for OMC work.
The following is a record of the opening and closing of valves and the pressure of the pressurization process.
The same process is used for k-log 26030. It is noted here for reference.
8:50 Turned on the air compressor near IXC
Turned on the FFU around the OMMT~OMC area
9:07 GVoomt Close
9:17 Pressurization was started by G-2class grade air (klog-25912) .
Pressure in OMC was 4.1 x 10^1 Pa
9:21 " 7.1 x 10^2 Pa
9:57 " 1.1 x 10^4 Pa
9:58 Increased air flow (Open the valve about 1 turn.)
10:08 Cylinder presure 12.8 MPaG
11:15 " 3.8 x 10^4 Pa
11:18 Cylinder presure 9.5 MPaG
Increased air flow (Open the valve about 1 turn. Increase secondary pressure from 0.9 kg/cm^2G to 1.0 kg/cm^2G. )
11:19 " 4.0 x 10^4 Pa
Increased air flow (Increase secondary pressure from 1.0 kg/cm^2G to 1.0 kg/cm^2G. )
12:03 " 7.2 x 10^4 Pa
12:20 " 8.4 x 10^4 Pa
12:40 " 9.8 x 10^4 Pa
Cylinder presure 1.0 MPaG
The pressurization process is terminated because the pressure in the OMC has reached almost atmospheric pressure at 12:40.
Uchiyama
I started pumping down OMC and OMMT by a dry pump from 12:34. Since the vacuum pressure reached 20 Pa at 14:30, I started TMP at SRM, and the TMP was normal at 14:50.
Kimura, Yasui
They closed 5 flanges of the OMC chamber.
The 5 flanges are 2-2, 2-3, 2-4, 2-6, and 2-8.
We used a new window flange at 2-3.
We put metal covers on the window flanges (2-2 and 2-3).
Uchiyama, Kimura
We opened GVsrm at around 11:10. Before this work we performed the following actions to avoid frosting ITMs.
1: Set BS safe
2: Start BS +X, BS+Y side TMPs
3: Close GVbsx, GBbsy
4: Open GVsrm
5: Disconnect the pumping unit of the SRM from the duct (close the GV of the pumping unit)
6: Start the ion pump of the SRM
7: Connect the pumping unit of SRM to the duct (open the GV of the pumping unit)
8: Close TMP's GV at SRM
9: Set SRM, SR3 safe
10: Open GVbsx, GVbsy
11: Stop TMP at SRM
12: Stop BS+X, BS+Y side TMPs
[Kimura and Yasui]
The BS side gate valve interlock setting was disabled to accommodate the pressure increase during SRM gate valve operation.
Thereafter, the setting of the interlock on the BS-side gate valve was enabled because the value of the pressure gauge that activates the interlock was 1.0 x 10^-5 Pa.
However, the threshold for interlock activation was temporarily increased by 0.2x 10^-5 Pa from 1.0 x 10^-5 Pa to 1.2x 10^-5 Pa.