Download
1 / 7
70 likes | 79 Views
AD tank filling & design issues. Liquid densities must be tightly controlled Feedback loops between liquid columns and pumps ˛ need column heights Overfill to rupture is possible Purge gas pressures must be equalized. AD Hydrostatics.
E N D
AD tank filling & design issues • Liquid densities must be tightly controlled • Feedback loops between liquid columns and pumps ˛ need column heights • Overfill to rupture is possible • Purge gas pressures must be equalized
AD Hydrostatics • Each acrylic vessel is an enormous hydraulic cylinder acting on itself • The overflow columns function as hydraulic pistons • The acrylic vessels are elastic with a non-linear DV/V vs pressure. Overflow column heights are a balance between a) stiffness of acrylic c) column diameters b) liquid density difference d) mass pumped into detector
Let r oil > r scintillator • Deflection of acrylic until forces balance • 450 kg force for every 1% density difference between scintillator and oil • Column height difference of 4cm for each 1% density difference • Diameter of overflow column is critical We need DV vs PRESSURE curve for both acrylic vessels DV/V at rupture is important parameter
Acrylic vessels appear “stiffer” for small diameter overflow columns and “softer” for large diameter columns Same DV Conversely, filling an overflow column to a preconceived height is dangerous
Divide detector into filling zones • Zone A: oil only • Zone B 106 kg force on acrylic bottom for each cm of height mismatch • Zone C: center vessel filled at constant rate while regulating other two flow rates • Zone D/E: overfill to breaking point possible even with a small difference in column height Level monitoring to cm accuracy is needed. Consider monitoring curvature of flat acrylic faces
CONCLUSIONS • Acrylic vessels are highly elastic. Need DV/V vs pressure and DV/V at failure • Accurate liquid densities needed now---can have major impact on acrylic design • Want LARGE diameter oil overflow and SMALL diameter scintillator overflow • Flexing of acrylic tanks is desirable if filling to pre-specified mass • Rupture of acrylic during filling is possible • Regulation of heights during fill (and drain!) • N2 purging system pressures are critical (±10 mbar)
