World's Smallest And Powerfull Vacuum Pumps :Developed By DARPA

DARPA-funded researchers recently demonstrated the world’s smallest vacuum pumps. This breakthrough technology may create new national security applications for electronics and sensors that require a vacuum.

Researchers at the University of Michigan developed three different pumps in three different pressure categories. From lowest to highest pressure, the categories are microplasma Penning ion high vacuum, Knudsen mid vacuum, and high-frequency peristaltic rough vacuum pumps to removing air from a sample chamber with a volume of one cubic millimeter, which is about one-tenth the volume of a grain of rice. These new technologies will enable many micro-scale devices which require a vacuum or a controlled flow of gas, such as Lab-on-a-Chip sensors, radio frequency MEMS switches and microscopic vacuum tubes. Pictured above is a 24-stage microscale rough pump that uses tiny micromachined hexagonal compartments, where each element of the array is either a pump or a valve.

DARPA sought a vacuum system no bigger than a US penny that is able to produce a vacuum of less than 100 microPascals (uPa, a billionth of atmospheric pressure) in a vacuum chamber with at least a cubic millimeter of volume (about the size of a grain of coarse sand). The vacuum system was to use less than a quarter of a watt, and contain instruments to accurately measure the pressure in the chamber.

MIT

A team at the Massachusetts Institute of Technology (MIT) has also developed three types of microscale gas pumps. This photograph shows a two-stage rough pump with curved surfaces that displace large volumes of gas and uses two valves to limit backpressure. This novel pump was created by focusing on efficiency to create a compression ratio of 4.6 per stage—the highest recorded value at this scale.

HONEYWELL

Honeywell International, Inc. demonstrated a microfabricated, turbomolecular pump that operates in the mid-vacuum and high-vacuum range. The pump design is analogous to a turbine, but in reverse. The blades on the rotor are angled and push gas outward as they spin, creating a vacuum in the center. Each of the blades on the fan is about half the size of the period at the end of this sentence.

The heart of the Honeywell pump is an exquisitely detailed turbine rotor about 1.5 cm (0.6 in) in diameter. Very little quantitative information has emerged on this pump, but judging from the figure, the outer 2.5 mm (0.1 in) of the rotor is covered with tiny turbine blades, so angled that, as the rotor spins, the blades pick up air from the central region of the rotor, and throw it out the edge of the rotor. There appear to be about 2,000 rotor blades, each of which is about 60 microns wide, 60 microns tall, and 10 microns thick.

“There have never been ionic or mechanical gas pumps at the microscale before,” said Shkel. “The CSVMP program 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 20 times smaller than custom-built pumps, but they also consume approximately 10 times less power to evacuate from atmospheric pressure to milliTorr pressures.”

Initially, CSVMP focused on applications with small mass spectrometry gas analyzers, which would enable better chemical and biological pathogen detection. As the program continued to develop smaller and more powerful pumps that could create vacuums at different scales, other applications became apparent.

“These microscale gas pumps may ultimately be required for laser-cooled atomic clocks, accelerometers and gyroscopes,” said Shkel. “Laser cooling systems require vacuums, but are often significantly smaller than the pumps themselves. It is possible that these pumps will help enable smaller, more accurate atomic clocks.

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Write by: RC - Monday, June 24, 2013