DARPA programme demonstrates tiny, powerful vacuum pumps
09 June 2013
DARPA-funded researchers at MIT, the University of Michigan and Honeywell International have demonstrated the world’s smallest vacuum pumps.
One of the pumps developed by the University of Michigan, a 24-stage microscale roughing pump that uses tiny micromachined hexagonal compartments, where each element of the array is either a pump or a valve.
The technology is aimed primarily at military applications, such as specialist electronics and sensors that require a vacuum, highly sensitive gas analysers that can detect chemical or biological attack, extremely accurate laser-cooled chip-scale atomic clocks and microscale vacuum tubes.
In 2008, DARPA’s Chip-Scale Vacuum Micro Pumps (CSVMP) programme set out to create a new class of ultra-high-performance vacuum micropump.
The programme achieved an ultimate goal of a vacuum pressure of 10-6 Torr for a tiny one millimetre-cubed compartment with the smallest, most power-efficient pumps ever created.
A team at MIT has developed this two-stage roughing pump with curved surfaces that displace large volumes of gas and uses two valves to limit backpressure
“The process of creating a vacuum in a room large enough to test a spacecraft, for example, is pretty straightforward,” says DARPA programme manager Andrei Shkel. “A sealed room, a large pump and ample power are all that is needed.
That approach does not scale down to microscale vacuum chambers that are slightly larger than a grain of sand.
"We had to harness new kinds of physics to develop these pumps, requiring precision and miniaturisation techniques that have never previously been attempted. The results are now available for future applications in the smallest, most sensitive electronics and sensors.
Honeywell's microfabricated, turbomolecular pump operates in the mid- and high-vacuum range. The pump design is analogous to a turbine, but in reverse. The fan blades (inset) are each about the size of a printed full stop
“There have never been ionic or mechanical gas pumps at the microscale before. The CSVMP programme has demonstrated both and more. The smallest commercially available pumps are the size of a deck of cards, which dwarf the vacuum electronics and sensors we want to attach our pumps to.
"These pumps are not only 300 times smaller than off-the-shelf pumps and twenty times smaller than custom-built pumps, but they also consume approximately ten times less power to evacuate from atmospheric pressure to milli-Torr pressures.”
The programme is reported to have reached a successful conclusion, with DARPA researchers at the University of Michigan, Honeywell International and the Massachusetts Institute of Technology (MIT) now having successfully demonstrated their pumps.