Difference between revisions of "Minutes-4-12-2012"
From GlueXWiki
| Line 29: | Line 29: | ||
- The first production cell with new Viton O-rings was installed and oxygen was measured (it took 4 days) 500-600 ppm at 330 ccpm gas flow and 900-1000 ppm at 220 ccpm. For comparison, before disassembling the four cells there with the original EPDM O-rings had ~7,000 ppm at 330 ccpm gas flow, an improvement of more than a factor of 3, but a factor of ~2 worse than in the testing chamber. There was a significant leak, that later turned out to be caused by a small piece of Kapton tape on the top of the O-ring. Since yesterday, we replaced the top end window and cathode type-3 with a cathode type-1 and Lexan sheet. This is to investigate to role of the flatness and possible frame deformation. | - The first production cell with new Viton O-rings was installed and oxygen was measured (it took 4 days) 500-600 ppm at 330 ccpm gas flow and 900-1000 ppm at 220 ccpm. For comparison, before disassembling the four cells there with the original EPDM O-rings had ~7,000 ppm at 330 ccpm gas flow, an improvement of more than a factor of 3, but a factor of ~2 worse than in the testing chamber. There was a significant leak, that later turned out to be caused by a small piece of Kapton tape on the top of the O-ring. Since yesterday, we replaced the top end window and cathode type-3 with a cathode type-1 and Lexan sheet. This is to investigate to role of the flatness and possible frame deformation. | ||
| − | - Due to the difficulties to maintain clean and flat surfaces needed for the Viton O-rings, we started looking again at the possibilities to use EPDM. We | + | - Due to the difficulties to maintain clean and flat surfaces needed for the Viton O-rings, we started looking again at the possibilities to use EPDM. We set up at Blue Crab a second oxygen testing place. There we started with the simplest configuration: spacer ring with EPDM O-rings between two Lexan plates: 220 ppm oxygen (to be compared to 400 ppm we measured before). As a next step, yesterday we added to the same configuration cathode type-1 with EPDM O-ring, expecting to have the final results tomorrow. |
| + | |||
| + | - Even we had a factor of 3 improvement, we expect ~0.5% oxygen for the whole package at 220ccpm. We would need a factor of 5 higher flow to have the oxygen below 0.1% what we had in the prototype. Another way to reduce the effect of the oxygen is to use less CO2, either going to 90/10 gas mixture or using methane instead of (some part of) CO2. Eugene, Bill, Beni insisted that we don't want to be constrained by the gas and we should continue to fight for lower oxygen. Bill proposed to put | ||
== Engineering == | == Engineering == | ||
Revision as of 18:06, 12 April 2012
April 12, 2012 FDC meeting
Agenda
- Production Construction Tracking (Dave)
- Production status
- Results from the oxygen studies (Lubomir)
- First production cell with Viton O-rings
- New tests with EPDM
- Engineering update (Bill)
- Frame deformations with new O-rings Ansys results,Ansys results
- Electronics update (Chris)
- Other
