lst gas system
DESCRIPTION
LST Gas System. R. Messner May 2004 Readiness Review. 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 - PowerPoint PPT PresentationTRANSCRIPT
1
LST Gas System
R. Messner
May 2004
Readiness Review
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
3
Gas Mix Instead of getting a specific mix approved,
we want approval for a region of mixes
0 20 40 60 80 100
0
20
40
60
80
100
Per Cent Argon
%CO2=100-%Ar-%Isobutane
Not 'Physical'
Representation of a three component gas
Possible Mixes
Bureau of Mines Tci
CERN Tci
4
Gas Mix The operating region takes into account the stability we have seen in the RPC system
0 2 4 6 8 10
7.5
8
8.5
9
9.5
10
Compare_errors_vs_flammable_region_II
Per Cent Argon (proposed limit, 9.7% isobutane at 0% argon)
Runnable Region (9.41 % isobutane at 0% argon)
Runnable Region +- 1.0% drift
Example Point (8.65% isobutane, 3% argon)
Per Cent Argon
All Operational Settings Are To Be Below the Blue Line
%CO2=100-%Ar-%Isobutane
5
G as In te rru p t B ox
M o n ito rs gas flow s;w ill sh u t o ff in pu ts ifflo w s or ra tio s areno t corre c t
(h o m e m a d e )
F low C o ntro l B o x
O n e m a ste r flo w ;s la ve s se t b y ara tio to ac tu a l f lo wo f m a ste r
M a ss F lo w C o ntro lle rs
C O 2 C O 2
A r A r
Iso Iso
M a ss F lo w M e ters
Pre
ssu
reS
ens
ors
M ass F lo w M ete r R e a d in gs
Ve n t
Sta tu s
S a m p leP o rt
A fourth mass flow meter can provide a tie-breaking vote in case of MFM/MFC disagreementCan also pick up small drifts in mixed gas flows
Shut-off solenoids will close if the gas mix drifts out of the allowed region
Mixing System Functionality
6
Gas Rack - in leak test
7
Gas Rack
8
Gas Interrupt Box Functionality
Reading InFrom Flowmeters
0-5 Volts
Reading Out
SolenoidPower
Trip?
Reading In Range?
To Monitor
To MonitorTo Monitor
ToSolenoids
ShutOffPower
S
S im p so n 2
%
S
S im pso n 2
%
Iso
CO2
S
S im p so n 2
%
Argon
Reading In Range?
Reading In Range?
S
S im p so n 2
%
Mix
9
GIB in checkout
10
Overview of the IR-2 Distribution
Layer Distribution Manifold with Resistors
Sextant Distribution Manifoldwith safety bubblers and rotameters
Left Side Modules
Right Side Modules
PSI “ H2O
Output Collection Manifold with Bubblers
Le ft H a lf
R igh t H a lf
Le ft H a lf
R igh t H a lf
11
Silica tubing flow resistor
12
Check of silica tubing flow resistance
0
1
2
3
4
5
0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04
Delta_P_thru_one_inch_of_tube
Delta P (inches H20) for 5.22 liters per hour thru one inch of tubeMeasurement y = 2.0575e-07 * x̂ (-3.9842) R= 1
Inner Diameter (inch)
Measured at 50 cc/min: Delta P = 1.8-2.0 inches H2O for a 1.875 inch long piece of 0.53 mm ID silicon tubing
13
Gas Shack Layout
22 feet
RPC
DCH
inertgas
DCHgas
DCHgas
elec
Cabinet
Term
inal
15.5Feet
12 Feet19 Feet
10 FeetCovered
North
CO2
Air
He
MH-6
ElectricalPanel
Fan
3.88 in
VMEcrate
Light
Light
DCH and RPC Manifold Panels
N2
Argon
Construct a new isobutane supply rack and manifold;Will have two isobutane shutoff valves, orifice
Two new inert gas supplies;Each will have a shutoff valve, orifice, overpressure releases
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 non-flammable 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
15
Spare Slides
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
+- 0.0005 out of 0.045
Or ~ 1.0 % of the reading
0.044
0.0445
0.045
0.0455
0.046
0 2000 4000 6000 8000 10000 12000
gasreadings_output_oct_dec_2003_cleaned
Fraction of Isobutane
Index
11/20 11/27 12/04 12/11 12/18
17
Recent performance of the RPC system
0
500
1000
1500
2000
Percentage Isobutane
Range
-1 % of nominal+1 % of nominal
Isobutane Fraction in Gas Mixture