Utilities 14 October 2008 Martin Nordby, Gordon Bowden.

UtilitiesUtilities

14 October 200814 October 2008

Martin Nordby, Gordon Bowden

LSST Camera Systems Integration

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ContentsContents

• Overview of services to camera

• Operating parameters for services

• Routing of utility lines

• Facility design overview

• Current issues


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Services to the CameraServices to the Camera

• Heat extraction and environmental control

– Cryogenic system

– Cryogen vapor return

– Purge system

– Fluorinert cooling system

• Operations and control

– Compressed air

– Cryostat backing vacuum

– Valve box backing vacuum

– Power

– Alarm signals out

– Data and control fiber lines

Utility Trunk

ValveBox

Camera Body

Cryostat

Trunk Fan Unit

Cold Plate

Cryo Plate

Camera Fan Unit

5X disconnect for Camera removal

2X bayonet disconnect for

Camera removal

AVacuum pumps

Back end vacuum

Focal Plane vacuum

L3 O-ring pump groove

Feedthrough flange pump

groove

L3 gasket pump groove

P

P

P

P

Cryostat vacuum Valve Box vacuum

Relief valve return

Compressed air

Nitrogen gas purge

Cryogen


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Cryogenic System Operating ParametersCryogenic System Operating Parameters

• Cryogenic cooling

– Closed-loop temperature control of cryo plate and cold plate

– Nominal temperature: -140oC

– Total capacity: 1400 W • FEE process heat: 600 W (cryo plate)• Cryo plate heat leaks: 16 W (cryo plate)• IR heat load: 98 W (cryo plate)• RCC process heat: 400 W (cold plate)• Cold plate heat leaks: 36 W (cold plate)• Transfer line losses: 250 W

– Minimum flow rate: 1 kg/sec

• Cryogen properties

– Cryogen: refrigerant R124

– Design mass flow rate: 1 kg/sec

– Design volumetric flow rate: 8.65 gpm

– Specific weight: 1.84

– Viscosity at -145oC: 0.012 kg-m/s(compare with water: 0.001 kg-m/s)

• Flow configuration

– Elevation difference: 93 ft (28 m)

– Total circuit length: 712 ft (217 m)

– Max pressure head: 87 psi

– Total line losses: 95 psi

Cold PlateCold Plate

Cryo PlateCryo Plate


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Camera Utilities Operating Parameters (1)Camera Utilities Operating Parameters (1)

• Cryogen relief valve

– Purpose• Exhaust of vaporized R124 refrigerant during cool-down, line purging, or over-pressure condition• Prevents venting to dome air

– Design parameters• Must handle 1 kg/sec flow rate at 100:1 expansion ratio, with < 2 atm back-pressure• Insulated to prevent condensation• Lines will run warm during normal operation

• Nitrogen gas purge

– Purpose• Temperature and humidity control of Camera and Utility Trunk volumes• Preserve clean environment in the Camera volume• Supply for emergency back-fill of cryostat vacuum volume

– Design parameters• Minimum 260 STP-liter capacity at 30 psi min pressure, for emergency back-fill• Closed-loop temperature controlled flow with re-heaters• Nominal temperature: dome temperature• Minimum flow rate: 2 L/sec of 30 psi nitrogen

• Fluorinert

– Purpose• Closed-loop temperature control of support electronics crates in the Utility Trunk

– Design parameters• Nominal temperature: dome temperature – T • 2700 W total capacity = 2400 W of pump heat + 300 W electronics heat• Minimum flow rate: 1 gpm


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• Compressed air

– Purpose• Power source for pneumatically-operated remote shut-off valves for cryogenic and fluorinert systems

– Design parameters• Filtered, oil-free air• ~75 psi minimum pressure• Minimum flow rate: 2 L/sec of 75 psi air

• Cryostat backing vacuum

– Purpose• Pumps down the cryostat from ambient, using roughing pumps on the ground• Provides mechanical backing vacuum for turbo-pumps during normal operation

• Valve box backing vacuum

– Purpose• Pumps down the valve box to prepare it for cool-down• Independent of cryostat system, allowing the cryostat to stay cold while the camera is being de-/re-mounted

from/to the telescope


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• Data and control fiber lines

– 62 fiber lines, total• Science data lines: 25 pairs of optical fibers• Guider, WFS data lines: 4 pairs of optical fibers• Control lines: 2 pair of optical fibers

• Alarm

– Direct copper lines for camera protection circuits

– Provide hardware enable/disable signals

• Power

– 6 kW on-camera capacity; 120V single phase (2x margin)• Cryostat electronics: 950 W• Support electronics: 250• Pumps: 2400 W


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Routing of Services to the CameraRouting of Services to the Camera

Service Qt'yRigid

Line SizeFlex

Line SizeDetails Restrictions Usage

Cryo cooling 2 3-1/2" O.D.4" O.D. bellows w/ over-braid

Vacuum-insulated 1-1/2" I.D. flex hose

23" min bend radius

Cooling for cryo plate and cold plate

Cryogen relief valve return line

1 3" O.D. 4" O.D. flex2" O.D. line with foam insulation

2" O.D. line with foam insulation

Return path for vapor

Nitrogen gas purge 2 1-1/2" O.D. 3" O.D. flex2 L/sec @ 30 psi max flow rate; 1/2" lines with foam insulation

Capable of 60 second back-fill of cryostat

Fluorinert 2 1-1/2" O.D. 1-1/2" O.D.1/2" O.D. lines, foam insulated for 1 gpm flow

Room-temp cooling of support electronics

Compressed air 1 1/2" O.D. 1" O.D. flex 2 L/sec @ 75 psi shop air Clean, oil-freePneumatically-actuated cryo valves

Cryostat backing vacuum

1 3" O.D.4" O.D. bellows w/ over-braid

Stainless steel tubing23" min bend radius

Pump-down line to evacuate cryostat and back turbo-pump

Valve Box backing vacuum

1 3" O.D.4" O.D. bellows w/ over-braid

Stainless steel tubing23" min bend radius

Pump-down line to evacuate cryostat and back turbo-pump

Data and control fiber lines

2 1/2" O.D. 1/2" O.D.Sumitomo 36-fiber bundle, jacketed

10" min bend radius

Science data output; camera control I/O

Alarm 1 1/2" O.D. 1/2" O.D. 25-pair 26 AWG cableHard-copper alarm and safety signals

Power 2 3/4" O.D. 3/4" O.D.Belden 4-conductor shielded, jacketed 10 AWG cable

7" min bend radius

Camera power

Total cross-sectional areas (in^2):Cross-sectional area 25.50 33.00w/ 33% margin 34.00 44.00w/ 50% packing fraction 68.00 88.00 = 6" x 16" rectangular package


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Routing of Camera Utility and Service LinesRouting of Camera Utility and Service Lines

test/staging mirror coating

data control office

cable wrap

platform lift shaft

telescope pier

entry mech.

cleanroom

whiteroom

camera utilities

Suite of camera maintenance rooms on east side of service & ops building

Approximate routing of utility runs from cameraon telescope:

On telescope mount & rotator to camera 76’+34’

To camera utility room - 281’+10% for indirect routing = 310’ (location of Polycold units)

From camera utility room to:- clean room - 30’ - white room - 50’- test/staging area - 80’

Elevation drape Flex Line 20’+5’ margin

From elevation drape to azimuth wrap 40’

Azimuth drape Flex Line 50’+20’margin

Through enclosure to S&O building 10’+ 40’

In building to camera utility equipment 30’

Section through Enclosure & Support BuildingSection through Enclosure & Support Building(showing routing of camera coolant lines)(showing routing of camera coolant lines)

Elevation drape to spider 55'Spider Length (custom pipe) 12‘ + 2x2’ FlexCamera Cable Rotator (flex line) 30’ +Wrap to Camera (flex line) 9'

Flex line: 50 + 20 + 25 + 4 + 30 = 129’Hard line: 30 + 50 + 40 + 76 =196’

FlexHard


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Ground FacilityGround Facility

• All camera utilities and service lines are routed to the Utility Room

– All support hardware for camera operations is located in the Utility room

– This includes UPS’, SDS and process controllers

• Total power estimate

– 66 kW needed• 51 kW for 3 Polycold units• 4.5 kW for pumps• 2.4 kW to camera for pumps• 1.2 kW to camera for power• 1 kW facility electronics• 3.9 kW miscellaneous

– We may be able to go to 2 Polycold units….

• All systems assumed to be water cooled, using facility chilled water

Ground Facility

N2

Polycold

R124 150KReservoir Heat X’er

N2

Gas head on reservoir

Polycold

Ground facilityinsulating vac

On-telescopeinsulating vac

Cryostat vacbacking pump

Pump 1Pump 2

Purge gas

Supply

Return

Facility Chilled Water

De

-Ga

sser

Cryogen Vacuum Tank

He

ate

r

Polycold

N2 Purge gas

He

ate

r

Pump Vacuum Tank

Compr air

Cryostat vacuumValve Box vacuum

Relief valve return

Compressed airNitrogen gas purge

Cryogen


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Camera Utilities Reliability and Fault ToleranceCamera Utilities Reliability and Fault Tolerance

• Redundancy/single-point failures

– No moving parts or valves in the cryostat• Fluid flow channels are in parallel• We have not investigated whether these 3 parallel channels are 2-for-3 redundant

– Valve box contains valves and flow instrumentation—this is presumably where problems would occur

• This is in a separate vacuum• The valve box can be dis-assembled in situ, but it is not yet clear if we can do this on the telescope

– Ground facility includes redundancy of critical components• Polycolds: 2-for-3 redundancy• Cryo pumps: either 1-for-2 redundancy or a “cold” spare ready for turn-on

• Servicing and repair concepts


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Open IssuesOpen Issues

• Cryo cooling technology

• Cryo system design details

• Transfer line design, routing, and installation

Utilities 14 October 2008 Martin Nordby, Gordon Bowden.

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Transcript of Utilities 14 October 2008 Martin Nordby, Gordon Bowden.