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VAC (Valves & Pumps)
tomotada.akutsu - 19:47 Monday 19 February 2024 (28628) Print this report
Strange shhhh sound around TMSX pendulum valve

As entitled. D. Chen found and I confirmed that strange shhhhhhhhhh sound from the pendulum valve at TMSX. The movie has been uploaded on Slack and reported to Uchiyama-san already.

Comments to this report:
nobuhiro.kimura - 20:41 Tuesday 20 February 2024 (28641) Print this report

[Kimura and M. Takahashi]
 We identified the source of the indicated compressed air leak.
The cause was the use of a parallel threaded seal joint with an O-ring where a tapered threaded seal joint should have been used.
 We are currently inquiring with the company that installed the piping as to the reason for the mis-specification of the fitting.
This wrong choice of fitting has been confirmed on all KAGRA pneumatic gate valves.
Therefore, it is necessary to replace the fittings with the correct ones.

nobuhiro.kimura - 9:04 Wednesday 21 February 2024 (28653) Print this report

The correct taper thread seal standard (dimensions) for gate valves is as follows.
φ800 and φ1000 large gate valve:  1/4" taper thread seal (R 1/4" ISO NPT)
φ400 pendulum type valve: 1/8" taper thread seal (R 1/8" ISO NPT)

nobuhiro.kimura - 19:10 Wednesday 13 March 2024 (28837) Print this report

[Kimura]
 The parallel threaded seal joint with O-ring, which was the cause of air leakage in the pendulum valve drive of the TMSX, was replaced with a regular tapered threaded seal joint.
 After the replacement, a leakage test was conducted, and it was confirmed that there was no leakage.
 Replacement with tapered thread seal joints is required for all KAGRA φ1000 gate valves, φ800 gate valves, and pendulum valves.
So far, replacement work has been completed at two locations, GVbsx and GVbsy. Replacement work will continue in the future.

Images attached to this comment
nobuhiro.kimura - 5:46 Friday 15 March 2024 (28857) Print this report

[Kimura]
 The parallel threaded seal joint with O-ring, which was the cause of air leakage in the pendulum valve drive of the TMSY, was replaced with a regular tapered threaded seal joint.

Images attached to this comment
nobuhiro.kimura - 13:23 Friday 15 March 2024 (28872) Print this report
[Kimura]
The parallel threaded seal joint with O-ring, which were the cause of air leakage in the valve drive of the GVmc and GVommt, were replaced with a regular tapered threaded seal joint.
After the replacement, a leakage test was conducted, and it was confirmed that there was no leakage.
Replacement with tapered thread seal joints is required for all KAGRA φ1000 gate valves, φ800 gate valves, and pendulum valves.
The following four gate valves are awaiting replacement.
1. GVitmx
2. GVetmx
3. GVitmy
4. GVetmy
The following 6 gate valves have been replaced with corrective parts.
1. GVmc
2. GVbsx
3. GVbsy
4. GVtmsx
5. GVtmsy
6 . GVommt
nobuhiro.kimura - 5:35 Wednesday 17 April 2024 (29248) Print this report

[kimura]

The parallel threaded seal joint with O-ring, which was the cause of air leakage in the valve drive of the GVetmx, was replaced with a regular tapered threaded seal joint.
After the replacement, a leakage test was conducted, and it was confirmed that there was no leakage.
Replacement with tapered thread seal joints is required for all KAGRA φ1000 gate valves, φ800 gate valves, and pendulum valves.
The following three gate valves are awaiting replacement.
1. GVitmx
2. GVitmy
3. GVetmy
 

nobuhiro.kimura - 10:30 Monday 22 April 2024 (29287) Print this report

[kimura]
  The parallel threaded seal joint with O-ring, which was the cause of air leakage in the valve drive of the GVitmx,
 was replaced with a regular tapered threaded seal joint.
After the replacement, a leakage test was conducted, and it was confirmed that there was no leakage.
Replacement with tapered thread seal joints is required for all KAGRA φ1000 gate valves, φ800 gate valves, and pendulum valves.
The following two gate valves are awaiting replacement.
1. GVitmy
2. GVetmy

nobuhiro.kimura - 11:37 Monday 22 April 2024 (29288) Print this report

[kimura]
  The parallel threaded seal joint with O-ring, which was the cause of air leakage in the valve drive of the GVitmy,
 was replaced with a regular tapered threaded seal joint.
After the replacement, a leakage test was conducted, and it was confirmed that there was no leakage.
Replacement with tapered thread seal joints is required for all KAGRA φ1000 gate valves, φ800 gate valves, and pendulum valves.
The following one gate valves are awaiting replacement.
1. GVetmy

nobuhiro.kimura - 6:09 Wednesday 22 May 2024 (29598) Print this report

[kimura]
  The parallel threaded seal joint with O-ring, which was the cause of air leakage in the valve drive of the GVetmy,
 was replaced with a regular tapered threaded seal joint.
This replacement work has completed the replacement of all gate valves driven by compressed air.

Images attached to this comment
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