Method and apparatus for rendering medical materials safe

• US 5,543,111 A
• Filed: 08/12/1994
• Issued: 08/06/1996
• Est. Priority Date: 07/06/1990
• Status: Expired due to Fees

• Current Assignee: Alion Science and Technology Corporation
• Original Assignee: IIT Research Institute (Alion Science & Technology Corp.)
• Inventors: Bridges, Jack E., Sharp, James W., Sresty, Guggilam C., Held, Jeffrey S., Bajzek, Thomas J.
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/290,002
• Time in Patent Office: 725 Days
• Field of Search: 422/20-23, 204/164, 250/455.11, 250/492.1
• US Class Current: 422/22
• CPC Class Codes: A61L 11/00 Methods specially adapted for refuse disintegrating medical waste B02C19/0075; disposal of medical waste B09B3/00
• CPC Class Codes: A61L 2/08 Radiation
• CPC Class Codes: A61L 2/12 Microwaves

Abstract

Infectious medical materials are rendered harmless by heating heterogeneous medical materials having wet and dry portions with a radio-frequency electric field. The medical materials may be comminuted prior to heating. The medical materials are exposed to the radio-frequency electric field in order to heat the medical materials. The medical materials may include sorted medical or veterinary waste which after heat treatment may be recycled.

Claims

1. A method of disinfecting and processing dielectrically heterogeneous bulk medical waste to inactivate pathogens, comprising the steps of:

comminuting the dielectrically heterogeneous medical waste into comminuted dielectrically heterogeneous medical waste particles having a predetermined size;

placing the comminuted dielectrically heterogeneous medical waste particles in a bulk dielectric processing container;

conveying the bulk dielectric processing container with the comminuted dielectrically heterogeneous medical waste particles therein through an Opening and into a treatment region of a treatment chamber; and

applying within the treatment region a transverse mode radio-frequency electric field from a pair of parallel plates, the transverse mode radio frequency electric field having a frequency in the range of about 3 megahertz to about 80 megahertz, the transverse mode radio frequency electric field heating the comminuted dielectrically heterogeneous medical waste particles to a temperature of 85°

C. to 125°

C., the transverse mode radio-frequency electric field substantially penetrating the comminuted dielectrically heterogeneous bulk medical waste particles and exhibiting a square of the electric field strength that varies by no more than a factor of two in the treatment region to produce disinfected comminuted dielectrically heterogeneous medical waste particles without substantially producing ionized gas.

2. A method of disinfecting and processing dielectrically heterogeneous bulk medical waste to inactivate pathogens according to claim 1, wherein the step of comminuting the dielectrically heterogeneous bulk medical waste comprises reducing the dielectrically heterogeneous bulk medical waste to comminuted dielectrically heterogeneous bulk medical waste particles in a size range of 0.25 to 0.50 inch.

3. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 1, wherein the step of applying the transverse mode radio-frequency electric field lasts for a duration of at least approximately 5 minutes.

4. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 1, wherein the step of applying the transverse mode radio-frequency electric field lasts for a duration of between 3 and 30 minutes.

5. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 1, further comprising, the step of sorting the dielectrically heterogeneous medical waste into plastics waste and general medical waste and placing the plastics waste and general medical waste into separate processing containers for plastics waste and general medical waste, respectively.

6. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 5, further comprising recycling the sorted medical waste by reusing the disinfected plastic waste and using the disinfected general medical waste as fuel.

7. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens comprising the steps of:

comminuting the dielectrically heterogeneous bulk medical waste into comminuted dielectrically heterogeneous medical waste particles having a predetermined size;

placing one of the comminuted dielectrically heterogeneous medical waste particle types in a bulk dielectric processing container;

adding water to the dielectrically heterogeneous comminuted medical waste particles;

conveying the bulk dielectric processing container with the comminuted dielectrically heterogeneous medical waste particles therein through an opening and into a treatment chamber; and

applying within the treatment chamber for about five minutes a transverse mode radio-frequency electric field from a pair of parallel plates, the transverse mode radio-frequency electric field having a frequency in the range of about 3 megahertz to about 80 megahertz, the transverse mode radio-frequency electric field heating the comminuted dielectrically heterogeneous medical waste particles to a temperature of about 85°

C. to about 125°

C., the transverse mode radio-frequency electric field substantially penetrating the comminuted dielectrically heterogeneous bulk medical waste particles and disinfecting the comminuted dielectrically heterogeneous medical waste particles without substantially producing ionized gas.

8. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 7, wherein the step of adding water further comprises adding a foam comprising water and a surfactant to the dielectrically heterogeneous comminuted medical waste particles.

9. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 7, further comprising the step of compacting the comminuted dielectrically heterogeneous medical waste particles.

10. A method of disinfecting and processing dielectrically heterogeneous medical waste to inactivate pathogens according to claim 7, further comprising the step of separating the dielectrically heterogeneous medical waste into material comprising plastic and refuse-derived fuel.