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Continuous-Flow System Produces Medical-Grade WaterA continuous-flow system utilizes microwave heating to sterilize water and to thermally inactivate endotoxins produced in the sterilization process. The system is designed for use in converting potable water to medical-grade water. Systems like this one could be used for efficient, small-scale production of medical- grade water in laboratories, clinics, and hospitals. This system could be adapted to use in selective sterilization of connections in ultra-pure-water-producing equipment and other equipment into which intrusion by microorganisms cannot be tolerated. Lightweight, port - able systems based on the design of this system could be rapidly deployed to remote locations (e.g., military field hospitals) or in response to emergencies in which the normal infrastructure for providing medical-grade water is disrupted. Larger systems based on the design of this system could be useful for industrial production of medical-grade water. The basic microwave-heating principle of this system is the same as that of a microwave oven: An item to be heated, made of a lossy dielectric material (in this case, flowing water) is irradiated with microwaves in a multimode microwave cavity. The heating is rapid and efficient because it results from absorption of microwave power throughout the volume of the lossy dielectric material. In this system, a copper tube having a length of 49.5 cm and a diameter of 2.25 cm serves as both the microwave cavity and the sterilization chamber. Microwave power is fed via a coaxial cable to an antenna mounted inside the tube at mid-length (see figure). Efficient power transfer occurs due to the shift in wavelength associated with the high permittivity of water combined with the strong coupling of 2.45-GHz microwaves with rotational-vibrational transitions of the dipolar water molecule.
Document ID
20090011191
Acquisition Source
Glenn Research Center
Document Type
Other - NASA Tech Brief
External Source(s)
http://www.techbriefs.com/component/content/article/5009
Authors
Akse, James R. (Umpqua Research Co. Myrtle Creek, OR, United States)
Dahl, Roger W. (Umpqua Research Co. Myrtle Creek, OR, United States)
Wheeler, Richard R. (Umpqua Research Co. Myrtle Creek, OR, United States)
Date Acquired
August 24, 2013
Publication Date
March 1, 2009
Publication Information
Publication: NASA Tech Briefs, March 2009
Subject Category
Man/System Technology And Life Support
Report/Patent Number
LEW-18159-1
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20090011183Collected WorksNASA Tech Briefs, March 2009
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