Method and apparatus for rendering medical materials safe

• US 5,476,634 A
• Filed: 03/23/1995
• Issued: 12/19/1995
• Est. Priority Date: 03/30/1990
• Status: Expired due to Fees

• Current Assignee: IIT Research Institute (Alion Science & Technology Corp.), James W. Sharp, Jeffrey S. Held
• Original Assignee: IIT Research Institute (Alion Science & Technology Corp.), James W. Sharp, Jeffrey S. Held
• Inventors: Held, Jeffery S., Bridges, Jack E., Sharp, James W., Sresty, Guggilam C., Bajzek, Thomas J.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): JASTRZAB, KRISANNE MARIE
• Application Number:
  US08/409,897
• Time in Patent Office: 271 Days
• Field of Search: 422/22, 422/26, 422/32, 422/38, 422/299, 422/21, 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 2/04 Heat A61L2/08 takes precedence
• CPC Class Codes: A61L 2/08 Radiation
• CPC Class Codes: A61L 2/12 Microwaves
• CPC Class Codes: B03B 9/061 the refuse being industrial
• CPC Class Codes: B09B 3/0075 Disposal of medical waste casings for used articles, e.g. sharps A61B50/362; sterilisation of refuse A61L11/00; disposal of used needles or syringes A61M5/3205; disintegrating medical waste B02C19/0075
• CPC Class Codes: B09B 3/20 Agglomeration, binding or encapsulation of solid waste
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2105/065 containing impurities
• CPC Class Codes: B29K 2711/12 Paper, e.g. cardboard
• CPC Class Codes: B29L 2031/753 Medical equipment; Accessories therefor bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008
• CPC Class Codes: H05B 6/782 wherein the material moved is food
• CPC Class Codes: Y02W 30/52 Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

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

Claims

1. A method of disinfecting bulk medical waste comprising the steps of:

confining a quantity of bulk medical waste comprising wet portions and dry portions in a covered treatment container; and

exposing the covered treatment container to a transverse mode time-varying electric field having a frequency of less than one hundred megahertz from a pair of substantially parallel energized electrode plates straddling the treatment container, the transverse mode time-varying electric field substantially penetrating the bulk medical waste and wherein the normalized heating ratio of the time-varying electric field varies by no more than about a factor of two to evaporate water from the wet portions of the bulk medical waste, transporting the resulting water vapor by convection and diffusion to the dry portions of the bulk medical waste, condensing some of said water vapor on cooler dry portions, reheating the condensed water by the persisting time-varying electric field, transferring heat by conduction to the previously dry portions of the bulk medical waste which the water contacts so that all portions of the bulk medical waste are substantially uniformly heated by the time-varying electric field to disinfect the bulk medical waste without subjecting the bulk medical waste to ionizing radiation.

2. A method of disinfecting bulk medical waste as defined in claim 1, further comprising the step of comminuting the medical waste into comminuted waste.

3. A method of disinfecting bulk medical waste as defined in claim 1, further comprising the step of heat soaking the heated bulk medical waste for a period of about 30 minutes wherein the heat soaking occurs following heating by the time-varying electric field.

4. A method of disinfecting bulk medical waste as defined in claim 1, wherein the treatment container confines the evaporated water at substantially greater than ambient pressure whereby the water is heated above 100°

C. to allow the bulk medical waste to be heated above 100°

C.