HIGH SPEED CENTRIFUGES
A recent near-disastrous failure in a Sorvall Super Speed centrifuge emphasizes the importance of exercising extraordinary caution in the use of such equipment. The centrifuge in question happened to be a Model RC-2B with swinging-bucket rotor, but user caution should be directed towards any high-speed units, particularly when swinging buckets are used.
Before starting to run-up check bucket to be positive it will swing freely to the horizontal position it will assume. Be sure that sample tubes are completely seated in the buckets. Failure to take these steps can result in a catastrophic de-centering if a stuck bucket suddenly becomes unstuck or a sample tube slips deeper into the bucket as a result of the enormous centrifugal forces developed at speed.
If at any time a high-speed centrifuge gives off sound the least bit different from normal, it should be stopped immediately. Even though the dynamic brake will be disabled, such an emergency shutdown should be performed remotely (e.g. stopped at the breaker feeding the centrifuge). Do not go near the machine until it is stopped, or nearly so. This may take considerable time, depending on aerodynamic drag.
Any evidence of corrosion is immediate grounds for retirement of a rotor. Careful inspection is particularly important in aluminum angle-head rotors. With a penlight, examine each hole in the rotor. "Crud" may be cleaned out, but do not deceive yourself by thinking that removal of the aluminum oxide cures the problem. After cleanup, the interior surfaces should be pristine with no black or gray stains, which are evidence of corrosion. The big concern is that the corrosion may be much deeper than it appears because of intergranular attack.
Although all high-speed centrifuges are heavily armored for protection from horizontally-propelled rotor pieces, some, including the RC-2B, have covers which can resist only minimal vertical forces and will fly open, permitting violent escape of rotor parts, as occurred with the unit referenced above. We are investigating retrofit possibilities to compensate for this, but in the meantime, any centrifuge with a latch-secures cover should be operated in as much isolation as possible. No one should have a work station adjacent to it; indeed, there should be an exclusion area of 15 feet or more in radius. (Some of the missiles from the failed centrifuge bounced and ricocheted even further than this.)
We do not at this time know what caused the RC-2B to fail. It has been returned to Sorvall for laboratory examination and we have been assured that findings will be relayed promptly to us. In any event, all high-speed centrifuges should be recognized as potentially lethal and should be managed accordingly.
If you need any assistance in high-speed centrifuge safety, don't hesitate to call for it at x5-3241.
QUESTIONS? Contact EH&S at (585) 275-3241 or e-mail EH&S Questions.
This page last updated 11/8/04. Disclaimer
