1. A. Wasem / TA1-GSTRT Meeting 20/02/20021 Results from Prototype CO 2 Cooling Gas System

2. A. Wasem / TA1-GSTRT Meeting 20/02/20022 Outline Motivation Layout Component Start / Stop procedures and problems Conclusions

3. A. Wasem / TA1-GSTRT Meeting 20/02/20023 Motivation Investigate pressure regulation on a small volume with extremely high flow To establish Start / Stop procedures with the aim to stay <  2 mbar. Main components functional tests. (valves, Turbines). Simulate missing elements, like volumes, manifolds, lengths and diameters of pipes.

4. A. Wasem / TA1-GSTRT Meeting 20/02/20024 Components Turbine RIETSCHLE SKG 226 Control valves 6.3 and 40 KVs Flow meter DELTAFLOW. 100 m3 –Differential pressure flow meter  p  4mbar @ 100 m3/h CO2 Sensors 0/50 mbar, 0/-100 mbar, ± 10 mbar Back-pressure regulator Buffer Volume of  100 l was added (see T.D.R) Two test volumes, 400 and 57 litres were tested.

5. A. Wasem / TA1-GSTRT Meeting 20/02/20025 How to start up ? Manual valve (by-pass) –Difficult to operate, bad stability Frequency controller –Ramping the turbine between 80 to 100 steps to full power (25 min) –Resulted in smooth increase of flow with good regulation in the test volume PID parameters –For booth regulation systems (PID1, PID2) were optimised Back pressure regulator –With the back pressure regulator (BP1) the input pressure of the test volume was increased and with that the main flow through it.

6. A. Wasem / TA1-GSTRT Meeting 20/02/20026 Starting up (Manual valve)

7. A. Wasem / TA1-GSTRT Meeting 20/02/20027 Starting up (Frequency controller)

8. A. Wasem / TA1-GSTRT Meeting 20/02/20028 Pressure and flow

9. A. Wasem / TA1-GSTRT Meeting 20/02/20029 Buffer pressure p3

10. A. Wasem / TA1-GSTRT Meeting 20/02/200210 Shutting down procedure No EV4, 5, 6. –Turn off pump resulted pressurising the test volume to > 10 mbar. Close at same time EV5, 6 + open EV4 –Separate high pressure part from test volume and open valve 4 to exhaust, in order to equalise inside and outside pressure –Standard safety back-up. –Safest way to switch off resembles a power cut. –A slow ramp down of the flow resulted always in overpressures due to the high pressure in the buffer volume

11. A. Wasem / TA1-GSTRT Meeting 20/02/200211 Shutting down procedure

12. A. Wasem / TA1-GSTRT Meeting 20/02/200212 Conclusion CO2 Cooling gas system will be very difficult to operate! Buffer volume is absolutely needed for disentangling pressure control around the pump unit and around detector-wheels. Pneumatic shut off separation valves (4, 5, 6) need to be fast (< 200 msec) in order to provide adequate detector safety. Flow increase of about 20% should be possible by increasing the input pressure of the 6 wheels (without changing the setting of the wheels). We feel, a second prototype with final component (as far as possible) is needed!