Bit OT: Surge risk with centrifugal blower

Single stage centrifugal blower, 500KW drive, discharge pressure about 30 KPag, suction more or less atmospheric. There's a distinct pressure dropoff
in the curve as the flow gets low, so surge is likely. Any ideas how concerned I should be about machine damage?.. the low pressure and low pressure ratio suggest that the risk may not be as high as with bigger machines.
Compressed material is not nice, unfortunately, so a simple blowoff on the discharge isn't an option.
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Am Dienstag, 26. Februar 2013 09:37:25 UTC+1 schrieb Bruce Varley:

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I know surge only as periodic backflow and not from a constant pressure dro poff. Pressure dropoff may be a result of falling compressor speed lines on the left side of the compressor map. Or a periodicity is filtered by the s ensor or by big volume after compressor.
If blowoff is no possibility, what about ported shrouds (http://www.turboby garrett.com/turbobygarrett/sites/default/files/PDF/Turbo%20Tech%20103.pdf)?
The surge results in increasing temperatures at the outer compressor blade area because of the fluid mass circulating inside the compressor. Maybe you have the possibility to measure the fluid temperature in that area and see if you stay inside spec.
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