About DBIS   | Story archive   | Contact DBIS  | DBIS home

Breakthrough for Breathing

Safer Ventilator Prevents Contamination From Water Condensation

September 1, 2006

Doctors can now keep patients who are in respiratory care safer with a new kind of ventilator. Ventilator oxygen is completely dry and needs to be humidified for the patient's comfort, but water can then condensate along the line, and allow the growth of microbes. The new system, based on capillary force, helps prevent condensation by hydrating oxygen closer to the patient's mouth.

read the full story...

Science Insider

Science behind the news is funded by a generous grant from the NSF

BACKGROUND: Capillary Force Vaporizer technology is used in many products: air fresheners, perfumes, and insect repellant, to name a few. About the size of a watch battery, CFV is a compact, heat-powered device that generates a powerful jet of pressurized vapor from an unpressurized liquid with no moving parts. Now, engineers are coming up with new ways to make vapor that could open the door to more applications in medicine.

HOW IT WORKS: Traditional methods of producing vapor use a process called atomization: they create tiny droplets, which evaporate into a vapor or gas. The CFV combines two basic natural principles into a single component that vaporizes a liquid and forcefully ejects it as a gas, without resorting to the complicated mechanisms normally needed to do so. Capillary forces arise when liquids and solids interact. A liquid is attracted to itself but also to the surface it contacts. If the surface is covered with tiny holes, the liquid "sticks" better. If the holes are larger, the liquid won't stick as well. A phase transition is the critical temperature/pressure point where one state of matter changes into another: in this case, liquid into gas.

The CFV has three ceramic discs bound together by a glaze. The top disc has a tiny hole in the center. The middle disc has many tiny pores, and the bottom layer has larger pores. The bottom layer is in constant contact with the liquid to be vaporized. Capillary action pulls the liquid up through the pores in the bottom layer, where it becomes trapped by the center disc. Heat is then applied to the top disc, and as the trapped liquid heats up, it evaporates into a gas. The gas naturally takes up more space than the liquid, and since it's contained in a small space, the pressure inside the small space gets higher. The higher pressure forces the gas out through the hole in the center of the top disc in a steady jet.

ADVANTAGES: Controlled vaporization of liquids is a critical component to many different products and processes, such as air fresheners, microchip manufacturing, and jet engines. Eliminating the need for moving parts makes the CFV very compact and efficient. When used in consumer products like fragrances or insect repellant, a CFV can disperse active ingredients directly, with no need for propellants, fillers, or disposable aerosol cans. And when used with liquid fuels, such as in a camping stove, the vapor produced by a CFV burns more like natural gas, reducing emissions. Researchers believe that many pharmaceutical and over-the-counter medications intended to be inhaled could be delivered more cost effectively using CFV technology -- such as asthma inhalers or nicotine vaporizer devices to help people quit smoking.

Video help

Latest stories

  • A Satellite Named Violet and a Student Named Amanda
  • Behind the Scenes with the K-Team
  • Deep Space Discoveries
  • Dogs Fighting Cancer
  • Earthquake! What's Your Risk

More information on this story

Vapore
Alameda, CA 94501
Tel: 510-865-1979


© 2011 American Institute of Physics