US 12,138,358 B2
Sterilization method using plasma
Paolo Seri, Civitanova Marche (IT); Gabriele Neretti, San Lazzaro di Savena (IT); and Carlo Angelo Borghi, Bologna (IT)
Assigned to Alma Mater Studiorum—Universita' Di Bologna, Bologna (IT)
Appl. No. 16/972,025
Filed by ALMA MATER STUDIORUM—UNIVERSITA' DI BOLOGNA, Bologna (IT)
PCT Filed Jun. 7, 2019, PCT No. PCT/IT2019/050129
§ 371(c)(1), (2) Date Dec. 4, 2020,
PCT Pub. No. WO2019/234781, PCT Pub. Date Dec. 12, 2019.
Claims priority of application No. 102018000006094 (IT), filed on Jun. 7, 2018.
Prior Publication US 2021/0236674 A1, Aug. 5, 2021
Int. Cl. A61L 2/14 (2006.01)
CPC A61L 2/14 (2013.01) [A61L 2202/122 (2013.01); A61L 2202/14 (2013.01); A61L 2202/15 (2013.01); A61L 2202/21 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A sterilization method using plasma for sterilizing objects, the method comprising the steps of:
introducing the objects to be sterilized into a sterilization chamber defined by an environment hermetically separated from the outside,
bringing said sterilization chamber to pressures lower than atmospheric pressure by means of a vacuum pump,
activating a plasma generator device disposed on at least one feed pipe leading to said sterilization chamber so that one or more gaseous compounds comprising a mixture of reactive oxygen species (ROS) and of reactive nitrogen species (RNS), and optionally free ions with positive charge, are generated by the plasma generator device and conveyed to said sterilization chamber,
feeding air along said at least one feed pipe and putting the latter in communication with said sterilization chamber for a determinate period of time to allow said gaseous compounds to enter said sterilization chamber and spread in a substantially homogeneous way therein, said period of time being equal to or more than the activation time of said plasma generator device, said air being a carrier fluid which conveys the gaseous compounds into said sterilization chamber,
controlling, by means of a control unit, the electric power used to produce the plasma during said activation step of the plasma generator device as a function of the composition and/or the quantity of reactive species present in said sterilization chamber, detected by suitable sensor means,
characterized in that said at least one feed pipe has a square section, in that said plasma generator device comprises four electrodes on the walls of said at least one feed pipe, according to a configuration wherein each of the four electrodes are oriented on a respective wall of the at least one feed pipe such that the central axis of symmetry of each of the four electrodes is arranged on the square section such that each electrode opposes another of the electrodes, and in that each of said electrodes has a circular or polygonal shape defining a configuration of symmetry with respect to a central axis of symmetry (Y).