Microwave disinfection and sterilization
Inventors
STULL, JR., WILLIS DON • Neuber, Andreas Alfred • Sharbutt, David E. • Brashears, Michael Todd • Brashears, Mindy M. • Alvarado, Christine • Brooks, J. Chance
Assignees
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Publication Number
US-9592313-B2
Publication Date
2017-03-14
Expiration Date
Abstract
A method and apparatus comprising microwave radiation pulses to reduce a microorganism population in an object.
Core Innovation
The disclosure describes a microwave disinfection/sterilization method and apparatus that use predominately non-thermal microwave radiation pulses to reduce a microorganism population on an object. A chamber exposes the object to microwave radiation, while the microwave radiation is delivered as repetitive pulses. The approach is intended to avoid altering object characteristics while reducing microorganisms.
The invention addresses reducing microorganisms while improving microwave uniformity and homogeneity through chamber geometry and wave manipulation. Microwave radiation is provided from a first magnetron and one or more second magnetrons, each with a waveguide positioned in communication with the chamber at an orientation providing pulses on respective axes. The waveguides may include a telescoping waveguide and may be implemented using a slot radiator.
Programmable pulse control delivers a series of repetitive pulses on the first axis and on the at least one second axis. The pulse series has a duration ranging from a fraction of a second to multiple seconds, and the programmable control panel controls repetitive pulse delivery. The non-thermal kill rationale is described as increasing peak electric field from pulsed microwaves while limiting temperature rise.
Claims Coverage
The identified independent claim describes an apparatus for reducing a microorganism population on an object by exposing the object in a chamber to microwave radiation delivered as repetitive pulse series on first and second axes using magnetrons with waveguides, including telescoping waveguides, and timed by a programmable control panel. The independent claim includes five inventive features.
Chamber exposure to microwave radiation
A chamber for exposing an object to microwave radiation.
First magnetron waveguide providing pulses on a first axis
A first magnetron having a first waveguide positioned in communication with the chamber at a first orientation to provide one or more first microwave radiation pulses on a first axis.
Second magnetron waveguide providing pulses on second axes with telescoping waveguide
At least one second magnetron, wherein each of the at least one second magnetron comprises a second waveguide positioned in communication with the chamber at a second orientation to provide one or more second microwave radiation pulses on at least one second axis, wherein the first waveguide, the second waveguide or both comprises a telescoping waveguide.
Programmable control delivering repetitive pulse series on first and second axes
A power supply connected to the first magnetron and the at least one second magnetron, and a programmable control panel in communication with the power supply and the first magnetron and the at least one second magnetron to deliver the one or more first microwave radiation pulses and one or more second microwave radiation pulses as a series of repetitive pulses on the first axis and the at least one second axis.
Pulse duration range to reduce microorganism population
Wherein each of the series of repetitive pulses have a duration ranging from a fraction of a second to multiple seconds to reduce the microorganism population on the object.
Claim coverage centers on a chamber-based microwave disinfection apparatus that uses a first magnetron and at least one second magnetron with waveguides oriented to deliver microwave radiation pulses on respective axes. It further covers telescoping waveguides and a programmable control panel that delivers repetitive pulse series with pulse durations in the recited range to reduce the microorganism population.
Stated Advantages
Rapid and energy-efficient sterilization is described.
The approach is described as environmentally friendlier sterilization.
The method is described as non-thermal, aiming to limit temperature rise.
The approach is described as not altering object characteristics.
Documented Applications
Reducing microorganisms such as MRSA and Salmonella on objects including cotton bedsheets, cantaloupe, jalapeno peppers, dog food, and peanuts is described.
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