LST Gas System. R. Messner May 2004 Readiness Review

Transcription

1 LST Gas System R. Messner May 2004 Readiness Review 1

2 Will cover a few of the items below Gas Mix the issue of what gas mixtures will be allowed in the LST system has been resolved FHA: O Neill, Budnick HEEC review Gas Mixing System In leak test Want to test output flows ASAP Integrate with the GIB Gas Interrupt Box (GIB) Finished with checkout Had found problems with firmware; fixed IR-2 Distribution Panels Flow restrictor in hand, checked out Gas Supply Manifolds Next to be assembled Gas Shack Safety System Expansion underway Electrical External Monitor System 2

3 Gas Mix Instead of getting a specific mix approved, we want approval for a region of mixes Representation of a three component gas %CO2=100-%Ar-%Isobutane Not 'Physical' Possible Mixes 20 Bureau of Mines T ci CERN T ci Per Cent Argon 3

4 Gas Mix The operating region takes into account the stability we have seen in the RPC system 10 Per Cent Argon (proposed limit, 9.7% isobutane at 0% argon) Runnable Region (9.41 % isobutane at 0% argon) Runnable Region % drift Compare_errors_vs_flammable_region_II Example Point (8.65% isobutane, 3% argon) %CO2=100-%Ar-%Isobutane All Operational Settings Are To Be Below the Blue Line Per Cent Argon 4

5 Mixing System Functionality Mass Flow Meters CO2 Mass Flow Controllers CO2 Vent Ar Ar Iso Iso Pressure Sensors Gas Interrupt Box (homemade) Monitors gas flows; will shut off inputs if flowsorratiosare not correct Flow Control Box One master flow; slaves set by a ratio to actual flow of master Status Sample Port Shut-off solenoids will close if the gas mix drifts out of the allowed region Mass Flow Meter Readings A fourth mass flow meter can provide a tie-breaking vote in case of MFM/MFC disagreement Can also pick up small drifts in mixed gas flows 5

6 Gas Rack - in leak test 6

7 Gas Rack 7

8 Gas Interrupt Box Functionality Reading In From Flowmeters 0-5 Volts Simpson 2 S CO 2 % Simpson 2 S Mix % Reading In Range? Simpson 2 Iso S % Reading In Range? Reading Out To Monitor Argon Simpson 2 S % Reading In Range? Trip? Shut Off Power Solenoid Power To Solenoids To Monitor To Monitor 8

9 GIB in checkout 9

10 Overview of the IR-2 Distribution Sextant Distribution Manifold with safety bubblers and rotameters Layer Distribution Manifold with Resistors Left Half Right Half PSI H2O Left Half Right Half Output Collection Manifold with Bubblers Left Side Modules Right Side Modules 10

11 Silica tubing flow resistor 11

12 Check of silica tubing flow resistance 5 Delta P (inches H20) for 5.22 liters per hour thru one inch of tube Measurement y = e-07 * x^( ) R= 1 Delta_P_thru_one_inch_of_tube Measured at 50 cc/min: Delta P = inches H2O for a inch long piece of 0.53 mm ID silicon tubing Inner Diameter (inch) 12

13 Gas Shack Layout North 12 Feet Terminal 22 feet CO2 10 Feet Covered He 19 Feet N in Light 15.5 Feet Cabinet Fan MH-6 RPC DCH elec inert gas VME crate Air Light DCH gas DCH gas Electrical Panel Argon DCH and RPC Manifold Panels Two new inert gas supplies; Each will have a shutoff valve, orifice, overpressure releases Construct a new isobutane supply rack and manifold; Will have two isobutane shutoff valves, orifice 13

14 Summary The loose ends involved in determining a permissible gas mix have been resolved Very close to having a functional mixing system with its monitor system to ensure a nonflammable and a runnable mix Use air or nitrogen, check the self consistency and stability of system It is important to keep moving ahead; sufficient and timely technical support is critical Want the gas rack in the gas shack before the end of May Delayed a bit because we want to get the manifolds done first; then we can do more things in parallel Expansion of Gas Shack safety system in progress EPICs monitor system will be the next item to attack 14

15 Spare Slides 15

16 Looked at the recent performance of the RPC system Snapshots taken a week apart, a half day at a time This is a measure of the stability of the gas mixture Fraction of Isobutane gasreadings_output_oct_dec_2003_cleaned 11/20 11/27 12/04 12/11 12/ out of Or ~ 1.0 % of the reading Index 16

17 Recent performance of the RPC system Isobutane Fraction in Gas Mixture Percentage Isobutane % of nominal +1 % of nominal Range 17