High-Vacuum Situations

Get Expert Advice to Pick the Right Pump for a Specific Application

“In the case of high vacuum, the pump system needs to meet the process demands and subsequent customer’s requirements,” says Christina Steigler, head of corporate communication at Germany-based Oerlikon Leybold Vacuum. She adds that the desired features are “in general, the same as for all industrial products: higher, faster, and with reasonable cost, and, if possible, ‘plug and play.’”

Where high vacuum is required, scientists face some specific challenges. One, says Keith Webb, engineering manager at Tuthill (Springfield, MO), is “carryover of process media that the user is trying to pull through the pump.” He adds, “In lab applications, that could be argon through the whole inert-gas range to condensable gases.” He adds that corrosion from chemicals can cause problems. “If you don’t have the right material construction, you’ll have corrosion in a short period of time,” he says.

A variety of variables come into play with high vacuum, but the particular needs depend intimately on the project at hand.

Scientific searches

A variety of research applications require high levels of vacuum. In Switzerland, for example, scientists at CERN use high-vacuum technology to search for black holes.

Instead of looking out, vacuum can help researchers look in, say, with electron microscopy. At the Central Microscopy Research Facility at the University of Iowa at Iowa City, director Randy A. Nesser helps scientists explore nature in very fine detail with electron microscopy. “Different electron emission sources require different vacuum environments for operation,” he explains. “Thermionic emitters have the least vacuum requirements; cold cathode field emission sources need vacuums approaching deep-space levels.”

So even similar applications can require different vacuums. As Nesser says about electron microscopy, “There are a host of different vacuum-generating technologies employed, depending on the final vacuum needed.”

Picking the product

“The art is in the understanding of the customer’s process demands and tailoring the system to the best technological outcome,” Steigler says. “The latest advance in this area is our software PASCAL. This enables us to calculate and simulate systems based on existing products, but also to configure products which will then be tailor-made for the processes.” She adds, “This is especially interesting for all R&D and analytical applications, which require high vacuum in most of the cases.”

Webb agrees that scientists need the right pump for the job. “The key is the up-front selection process,” he says. “You need the right pump for the application, and that means the right vacuum level, flow rate, and gases you will use.” He adds, “We have a tool on our site where you can provide your requirements, and then one of our engineers looks at it from an application standpoint to help the customer select the right equipment.” Webb points out that every pump comes with pros and cons, which makes it even more important to get the one that fits your specific needs.

To enhance the range of pumps, Oerlikon developed its TURBOVAC i/X line. “The flexible concept is the basis for adapting this pump to customers’ needs,” Steigler says. “Within 12 weeks we are able to create specific pumps for process applications.”

For lab applications, Webb says, “Our two-stage, oilsealed rotary piston pumps are more robust and durable than most other technologies that are in existence.” As examples, he mentions the KC and KTC series.

As Nesser concludes, “The keys to ensuring the correct vacuum level are selecting the appropriate vacuum technology and using the correct vacuum-monitoring gauges.” All of these need to be tailored to the science or engineering at hand to keep the appropriate vacuum and make your processes run right.

For additional resources on vacuum pumps, including useful articles and a list of manufacturers, visit www.labmanager.com/vacuum-pumps