Steris Inc.

John Masefield

Sergey Alexandrovich Korenev

Jerry Kriebel

Jerome A Dzwierzynski

Charles P Truby

Stephen Scott Johnson

A source of radiation ( ), particularly a pulsed accelerated electron beam, directs a beam of radiation through an irradiation chamber ( ). The irradiation chamber is depleted of oxygen and oxygen containing gases, such as being drawn to a vacuum of 10 or greater Torr by a vacuum pump ( ). Particulate fluoropolymer material is entrained ( ) in substantially oxygen free gas and conveyed through the irradiation chamber. The accelerated electrons break chemical bonds in the fluoropolymer particles and electrostatically charge the particles. Magnetic fields ( ) of different polarity rotate the charged particles such that they are irradiated from different sides. The irradiated fluoropolymer particles are cooled ( ) and separated ( ) from the entraining gas. The entraining gas is recirculated through pneumatic line ( ) for a continuous cycle.

Apparatus for irradiating for fluoropolymer materials

A particle accelerator ( ) is disposed between a first shielded processing chamber ( )and a second shielded processing chamber ( ). The accelerator selectively feeds a higher energy (e.g., 10 MeV) electron beam to the first processing chamber and selectively feeds a lower energy (e.g., 5 MeV) electron beam to the second processing chamber. A conveying system ( ) transports article carriers to and through the first processing chamber. At a processing table ( ), the articles are conveyed at a closely controlled speed through the electron beam for uniform dosing of an article to be irradiated. A loading station ( ) and an unloading station ( ) supply and remove articles from the first processing chamber. Beam bending magnets ( ) change the direction of an electron beam between the first processing chamber and the second processing chamber. A second conveying system, such as a reel-to-reel system ( ) for processing articles of indefinite length transported on reels and rolls, conveys articles through the second processing chamber.

Single accelerator/two-treatment vault system

An accelerator ( ) generates an electron beam that is swept ( ) up and down to form an electron beam ( ). A conveyor ( ) moves items ( ) through the electron beam for irradiation treatment. A first array of inductive electron beam strength detectors' ( ) is disposed between the origin of the electron beam and a first item to be irradiated to measure the strength of the electron beam entering the item at a plurality of altitudes. A second array ( ) of inductive electron beam strength detectors is disposed on the opposite side of the item to detect the strength of the electron beam exiting the item at the plurality of altitudes. In the illustrated embodiment, another item is positioned to be irradiated by the radiation that is passed through the first item. The second array thus detects the electron beam strength entering the second item and an analogous array ( ) measures the electron beam strength exiting the second item. A processor ( ) determines the absorbed dose of radiation absorbed by each of the first and second items. The dose information is archived ( ). The dose information is compared by a parameter adjustment processor ( ) with target doses and deviations are used to control one or more of MeV or beam current of the electron beam, the sweep rate, and the conveying speed of the items. Each of the inductive detectors ( ) includes a ferrite member, such as a ferrite ring ( ). A plurality of coiled loops ( ) are mounted around a periphery of the ferrite ring.

Real time monitoring of electron beam radiation dose

A source of radiation ( ), particularly a pulsed accelerated electron beam, directs a beam of radiation through an irradiation chamber ( ). The irradiation chamber is depleted of oxygen and oxygen containing gases, such as being drawn to a vacuum of 10 or greater Torr by a vacuum pump ( ). Particulate fluoropolymer material is entrained ( ) in substantially oxygen free gas and conveyed through the irradiation chamber. The accelerated electrons break chemical bonds in the fluoropolymer particles and electrostatically charge the particles. Magnetic fields ( ) of different polarity rotate the charged particles such that they are irradiated from different sides. The irradiated fluoropolymer particles are cooled ( ) and separated ( ) from the entraining gas. The entraining gas is recirculated through pneumatic line ( ) for a continuous cycle. In an alternate batch processing embodiment, the fluoropolymer material is placed in the shallow container ( ) which is sealed and evacuated. The container is conveyed through the pulsed electron beam.

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Far Hills, NJ, United States of America

John Masefield