The cleanroom vacuum's star is rising
04/01/2002
Applications continue to evolve for this unlikely hero
Hank Hogan
MALVERN, PA-Nature may abhor a vacuum, but cleanroom manufacturers do not-especially if it's used for contamination control.
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The United States Postal Service (USPS) also doesn't dislike equipment that sucks. The USPS is testing 800 vacuum cleaners from CFM, an Italian company that's part of Nilfisk-Advance A/S (Copen hagen, Denmark). If the machines can clean up suspected anthrax, the result could be an 8,000-piece order reportedly worth billions.
Complete with multiple HEPA and ULPA filters, the devices can be found in state-of-the-art semiconductor facilities, modern pharmaceutical plants and elsewhere. Other cleanroom vacuum equipment companies include Terra Universal (Anaheim, CA) and Spencer Turbine (Windsor, CT).
What cleanroom manufacturers want out of these cleaners is less-less contamination. "We want it to be better than the class that we're in. In other words, if the room is an ISO Class 10 at 0.2 microns, you're allowed 75 particles per minute. We want to see it well below that," says Joe Rauchet, a member of the technical staff at Agere Systems (Allentown, PA).
Formerly part of Lucent, Agere is a leader in communications components. Rauchet notes that vacuum cleaners are used in various Agere cleanrooms, which range down to an ISO Class 10 and below. At these sites, the vacuum machines clean up manufacturing waste that can't be handled other ways. For instance, breaking a silicon wafer results in a shower of fine particles, some of which lodge in difficult to reach places. Also, there are process tools that leave chambers coated with residues and fine dust.
At the other end of the spectrum are operations at Merck & Co. (Whitehouse Station, NJ). Some of the company's manufacturing is done in ISO Class 8 cleanrooms, where microbial contamination is controlled through the use of autoclaves and other sterilization procedures.
These facilities produce live viruses, sterile pharmaceuticals and other disinfected supplies. According to manufacturing associate supervisor Rich Peterson, one of the main uses for vacuum equipment in this setting is manufacturing cleanup. Peterson cites an example of a machine assembly room, where connectors, tubing and other components are used to construct production equipment. In addition to the desired equipment, one result is small and dispersed debris.
"We clean up that room every morning before production," remarks Peterson. This is done with portable cleanroom vacuum cleaners.
In all this vacuuming, however, cleanroom manufacturers have to make sure that what's sucked up isn't blown out. In the case of some facilities, such as those in an ISO Class 8, the concern is with particles that are visible. Thus, a naked eye inspection is enough. In other cases, the only way to make sure the equipment isn't contributing to contamination is to check it with a particle counter in all the right places.
As Rauchet explains, "We turn them on and we scan the filter face, and then we scan around where the seal meets the body because that's your biggest pressure buildup right there."