TK Dry Gas System Operation System overview Dry Gas Consumption Interlocks and thresholds Documentation Operational model Final comments.

TK Dry Gas System Operation

System overview

Dry Gas Consumption

Interlocks and thresholds

Documentation

Operational model

Final comments

Gas sources

• N2 dewar– 110 Nm3/hr max.

• 3 x air compressors @ 6 bar– 1 x 39 Nm3/hr– 2 x 50Nm3/hr

• Back-up bottles (only for the ‘cold’ systems)– 4 x 120 m3– Pressure reduced at surface from 200 to 7 bar– Pressure relief valve @ 12 bar

Tracker N2 system

Filters – particulate+ oil

Parallel dew pointmeters (interlock)

DT1 pressure + flowmonitoring (DIP)

ECAL ES

From N2 dewar

Extra flow meteron line to TKfor interlock

Tracker N2 + air systemCan select linefor DP monitoring

Air / N2master switch

Pneumatic valveswith state transmitters

Electro-Pneumatic valvesfor interlock

Switch-over panel

From bottles

Fromcompressors

TK, ECAL + HCAL

Small dryer for ECAL / HCAL

Sub-detector Max. flow (Nm3/hr)

TK internal volume 32.0TK PP1 boxes 24.0

ECAL ES 9.6ECAL EE 3.8ECAL EB 14.4HCAL HF 2.4

HCAL HE-HB-HO 11.5N2 Total 97.7

Cooling Boxes (Dry Air only)

7

Sub-detector Flow (Nl/hr)

Pressure (mbar)

Gas

TK internal volume 17006 600 N2

TK PP1 boxes 17344 550 N2

ECAL ES 2138 100 N2

ECAL EE 3286 420 N2

ECAL EB 10930 1250 N2

HCAL HF 1784 1000 N2

HCAL HE-HB-HO 9208 1550 N2

N2 Total 61696

SS1 Cooling Box 12000 5000 Dry AirSS2 Cooling Box 12000 5000 Dry Air

Pixel Coolong Box 4800 5000 Dry AirTS1 Cooling Box 1200 5000 Dry AirTS2 Cooling Box 1200 5000 Dry AirPS1 Cooling Box 4800 5000 Dry AirPS2 Cooling Box 4800 5000 Dry AirCooling Boxes (Dry Air only)

40800

Consumption

Design Max. flows

Present consumption15/04/10

Interlocks and ThresholdsRequested Interlock Logic.

All the hardware to implement it is there. Machi’ s talk for details.

Switch From

To If Value Action

N2 Dry Air N2

Pressure< 2 barg Automati

cN2 Dry Air N2 Dew

point> -45o C Forced

N2 Dry Air N2 Flow < 12 Nm3/h

Forced

Dry Air Bottles Dry Air Pressure

< 3 barg Automatic

Dry Air Bottles Dry Air Dew Point

> -15o C Forced

Dry Air Bottles Dry Air Flow

< 12 Nm3/h

Forced

Thresholds table

Documentation• The CMS Inertion and Flushing System : Technical Guide

– Functionality– Interlocks and monitoring– Failure scenarios and recovery procedures– System maintenance– Contact persons– Filter specifications– Spare parts list– Hyperlinks to Schematics, dryer manuals, pipes distribution, switch over panel pneumatic layout.

• Mass flowmeters calibrations• Rotameters calibrations• Instrumentation documentation 

To be stored in a better place than my hard drive.

Operational model so far……• No CMS Dry gas system maintenance crew.• Operation and maintenance based on the “good will” system.• Overall Experts: Stefano Moccia, Nick Lumb.• Distribution gas racks experts: PH-DT (Andrea D’ Auria, Roberto Guida, Albin

Wasem).• Monitoring:

– PH-DT for the distribution racks (pressures and flows to all the subdetectors). Info available via DIP.– TK (flow to the TK volume, valves state, switch over panel, Dew points).

• A good number of people in the TK community has helped to run the system.• Occasional interventions for small upgrades, dryer maintenance and tests.• This model has survived so far because the system is quite stable and has not given

major problems. • Need to transfer responsibility to PH-DT in order to centralize the operations and

maintenance especially if we are going towards colder running conditions for cooling• Need to mesh the two monitoring systems• Need to add some more parmeters to the monitoring (i.e. bottles supply pressure, driers state…..).

Dry Gas system summary

•At the present CMS is flushed with N2 (about 62 Nm3/hour) which is the default state for the dry gas system during operations.•The N2 provides the CMS inertion and necessary dryness inside the Vac Tank. •The N2 system has proven to be quite stable and reliable.•The Dry Air system is the backup for N2, but, of course, provides only the dryness. •The only “normal” failure modes for N2 and Dry Air systems are low pressure or high humidity. Tests have proven that the system reacts properly.• Power cuts are taken care (supposedly) by UPS and Diesel. It has never been fully tested.•TC has determined that if there is a switch to Dry Air due to some failure of the N2 system, there is a max waiting time of 1 hour to have the N2 back otherwise the detectors inside the VacTank need to power off.•Better operational model to setup.

Some worries for the Dry Air system as a backup for the N2:–The flushing and the instrument air share the same source (4 compressors for about 139 Nm3/hour).–If there is a switch to Dry Air (N2 problems shutdown configuration with CMS open), with the present consumption, the compressors won’ t be able to keep up with the demand for long.–This could cause a possible failure of the instrument air system causing systems shutdown.–This problem will become more evident in the future when Tracker and Preshower will run at way below subzero temperatures.–Decouple the instrument air from the CMS flushing is recommended along with larger dry air source.– Reduce drastically the consumption for the cooling boxes by improving the sealing, switching to N2…….