Sterilization system and method using non-thermal plasma generation

Abstract

A sterilization system and method using non-thermal plasma (NTP) ionization is disclosed. An exemplary method for inactivating viable microorganisms includes generating DC or AC, bipolar or steady-state non-thermal plasma (NTP) using a plurality of ceiling-mounted ion emitter modules 104, each equipped with a high voltage power supply (HVPS) 110, to generate DC or AC, bipolar or steady-state ion emitter modules 104 within a predetermined volume 118, 120, based on the geometry of the predetermined volume, to inactivate viable microorganisms.

Description

[Technical Field]

[0001] [Related Applications] This international application claims priority to U.S. Patent Application No. 16 / 204,567, entitled "Systems and Methods for Sterilization Using Nonthermal Plasma Ionization," filed November 29, 2018, and U.S. Provisional Patent Application No. 62 / 592,785, entitled "Systems and Methods for Sterilization Using Nonthermal Plasma Ionization," filed November 30, 2017. The entire contents of U.S. Patent Application No. 16 / 204,567 and U.S. Provisional Patent Application No. 62 / 592,785 are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE This disclosure relates to sterilization, and more particularly to sterilization systems and methods using non-thermal plasma ionization. [Background technology]

[0003] Due to historical epidemics of disease / infection transmission in healthcare settings, including medical device and / or pharmaceutical manufacturing, techniques to address transmission reduction / elimination have been explored and implemented. Transmission reduction has been achieved for specific enclosed operations (e.g., autoclave changes), but not for the general environment where substantial amounts of viruses, bacteria, and / or spores are collected and redistributed (i.e., transmitted). Summary of the Invention

[0004] As more fully set forth in the claims, and substantially as illustrated by and described in connection with at least one of the drawings, there is provided a sterilization method and system using non-thermal plasma generation (ionization).

[0005] These and / or other aspects will become apparent or more readily understood from the following description of exemplary embodiments taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of an example non-thermal plasma sterilization system according to aspects of the present disclosure. [Figure 2] 1 is a flow chart depicting an example method for inactivating viable microorganisms using non-thermal plasma sterilization, according to an aspect of the present disclosure. [Figure 3] 1 is a flowchart illustrating an example method for determining the number and configuration of DC or AC, bipolar or steady-state ion emitter modules according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] The figures are not necessarily drawn to scale. Where appropriate, like or identical reference numbers are used to refer to like or identical components.

[0008] The disclosed example methods and systems typically comprehensively address medical surgical areas, laboratories, and pharmaceutical or medical device manufacturing spaces by continuously disinfecting infectious microorganisms in place, both on surfaces and in the air. In particular, the disclosed example methods and systems use non-thermal plasma (NTP) to sterilize and / or kill viruses, bacteria, and spores attached to airborne particles, whether aerosol droplets, airborne molecular contaminants, or large particles generated by human activity in the local environment, continuously and / or in real time.

[0009] In some examples, the NTP generation system is installed in the ceiling of an existing structure or designed to be integrated into a facility during the planning stages. The disclosed example systems are modular, reducing the difficulty of retrofitting an already constructed facility. These disclosed systems are referred to as ceiling ionization systems, ceiling-based ionization systems, and / or room ionization systems.

[0010] Disclosed example systems include comprehensive digital NTP generation, control, and monitoring using computer-based software on either a stand-alone PC or VM (Virtual Machine) device. In some examples, a wireless (e.g., infrared) remote handheld programming unit enhances system programming and maintenance capabilities.

[0011] An exemplary disclosed method for inactivating viable microorganisms includes installing a plurality of ceiling-mounted, direct current (DC) or alternating current (AC), bipolar or steady-state ion emitter modules within a predetermined volume based on the geometric shape of the predetermined volume, and inactivating the viable microorganisms by generating a DC or AC, bipolar or steady-state non-thermal plasma (NTP) using the plurality of ceiling-mounted ion emitter modules, each equipped with a high voltage power supply (HVPS).

[0012] In some examples, installing the plurality of ceiling-mounted ion emitter modules includes arranging the plurality of ceiling-mounted ion emitter modules to have a module density within a predetermined volume based on a target ion density. In some such examples, the target ion density corresponds to a sub-volume within the predetermined volume. In some examples, installing the ceiling-mounted ion emitter modules includes providing a stainless steel shroud to the ceiling-mounted ion emitter modules to protect emitters of the ceiling-mounted ion emitter modules.

[0013] Some example methods further include connecting the plurality of ceiling-mounted ion emitter modules to a controller module and controlling the plurality of ceiling-mounted ion emitter modules with the controller module. In some examples, generating the non-thermal plasma includes controlling at least a portion of the plurality of ceiling-mounted ion emitter modules to generate the non-thermal plasma in at least one of a pulsed DC mode, a steady-state DC mode, or an AC mode.

[0014] In some example methods, generating the non-thermal plasma includes generating a non-thermal plasma having alternating polarity. In some examples, generating the non-thermal plasma includes generating the non-thermal plasma at different plasma densities using different ones of a plurality of ceiling-mounted ion emitter modules. In some examples, generating the non-thermal plasma further includes causing the non-thermal plasma to traverse a predetermined volume.

[0015] In some example methods, generating the non-thermal plasma includes inactivating at least a threshold percentage of bacteria, spores, fungi, and viruses present in the predetermined volume, hi some examples, generating the non-thermal plasma includes generating a neutral net charge.

[0016] Figure 1 shows a schematic diagram of an example non-thermal plasma sterilization system 100. The example system 100 of Figure 1 can be used to provide sterilization of an entire room 102 from microorganisms, whether airborne or surface-borne, such as bacteria, spores, fungi, and / or viruses. The example system 100 is modular and can be installed in new rooms and / or retrofitted into existing rooms of any size or configuration.

[0017] The example system 100 includes one or more ceiling-mounted ion emitter modules 104, which can be either AC or DC type and / or can operate in bipolar or steady-state modes. The modules 104 can be mounted in any desired configuration, such as a spaced grid. The density and configuration of the modules 104 within the grid arrangement can be based on the desired level of ion coverage (e.g., the ion density required to achieve a particular level of sterilization).

[0018] Each of the example ion emitter modules 104 in Figure 1 generates a DC or AC, bipolar or steady-state non-thermal plasma (NTP) via two separate emitters 106, 108 powered by individual DC or AC high voltage power supplies (HVPS) 110. The HVPS 110 can provide the same or different emitter outputs to each of the ion emitter modules 104. In some examples, the HVPS 110 provides a voltage between 0 kVDC and 20 kVDC and a current between 0 μA and 2 μA. The example HVPS 110 can be powered by low voltage (e.g., 24 VAC or VDC) wiring.

[0019] The example ion emitter module 104, either AC or DC type, can be operated to generate large and widespread NTPs using variable pulse intervals or steady-state and / or variable power settings. The DC or AC, bipolar or steady-state NTPs generated by the ion emitter module 104 spread to fill the sealed chamber 102 with alternating polarity NTPs. The example ion emitter module 104 can be operated using plasma generation modes such as pulsed DC mode, steady-state DC mode, standby mode, and / or any combination of modes. The ion emitter module 104 is constructed of materials that are highly resistant to sterilization chemical processes commonly applied in controlled medical, laboratory, or manufacturing spaces. Example materials include stainless steel and / or any other material specified by industry specifications.

[0020] The ion emitter modules 104 (DC or AC, bipolar or steady state) in the system 100 are digitally controlled using one or more digital controllers 112, 114. The example digital controller 112 controls a first set of ion emitter modules 104, and the example digital controller 114 controls a second set of ion emitter modules 104. The example digital controllers 112, 114 may differ in the number of ion emitter modules 104 they can control and / or the features they can provide. The ion emitter modules 104 are individually addressable by the controllers 112, 114. In some examples, one of the controllers 112, 114 in a multiple-controller system may be designated as a master controller.

[0021] The ion emitter modules 104 can be connected in parallel and / or daisy-chained for power and / or control purposes. The ion emitter modules 104 are individually programmable via the digital controllers 112, 114, via a software manager program running on a general-purpose computer, and / or via a handheld programming device. An example software manager program can, for example, display an emitter pod layout map with visual and / or system alarm mode processing and / or manage emitter pod maintenance alarms, emitter pod failures, performance degradation, and / or any other configuration and / or diagnostic information. The example controllers 112, 114 and / or ion emitter modules 104 are accessible and / or programmable via the digital controllers 112, 114 or a handheld terminal at the location of a particular emitter module.

[0022] The example ion emitter modules 104 have wireless communication capabilities (e.g., infrared, WiFi, Bluetooth, NFC, Zigbee, etc.) and can be individually programmed directly from below via a handheld wireless programming device 116. The programming device 116 can be used to verify the configuration of one or more ion emitter modules 104.

[0023] The example HVPS 110 and / or example controllers 112, 114 may be located within the room 102, directly adjacent to the room 102 (e.g., above the ceiling), and / or remotely from the ion emitter module 104 (e.g., in a different room).

[0024] Although the example system 100 is illustrated with three ion emitter modules 104, any number of ion emitter modules 104 and / or controllers 112, 114 may be used based on the desired ionization coverage for a particular room and / or portion of a room. The example ceiling-mounted system 100 may be configured to uniformly cover the entire space from ceiling to floor of the room 102 in which the system 100 is installed.

[0025] In some examples, sub-volumes 118, 120 or sub-regions of a given room may be selectively ionized to provide a localized target coverage and / or different sub-volumes or sub-regions of the room 102 may be ionized at different ion densities. For example, the sub-volume 118 of the room 102 may have a higher density of ion emitter modules 104 than the sub-volume 120 of the room 102. The number and / or configuration of the ion emitter modules 104 is selected and / or determined based on the ion density of the room 102 and / or the sub-volumes of the room 102.

[0026] In operation, the ion emitter module 104 generates a DC or AC, bipolar, or steady-state non-thermal plasma containing positive ions 122 and negative ions 124 while producing a substantially neutral net charge to inactivate airborne and / or surface-borne microorganisms (e.g., bacteria, spores, fungi, and / or viruses). The ion emitter module 104 can generate non-thermal plasma with alternating polarity and / or simultaneously generating ions with both positive and negative polarities (e.g., using different electrodes).

[0027] Depending on the configuration of the ion emitter module 104 and / or the plasma generation mode, the example ion emitter module 104 can generate non-thermal plasma with different plasma densities in different portions of the chamber 102. The ion emitter module 104 generates the non-thermal plasma to cause ions 122, 124 to traverse the entire chamber 102 and / or at least a predetermined volume of the chamber 102.

[0028] Exemplary embodiments of the ion emitter module 104 and controllers 112, 114 are described in U.S. Patent No. 8,861,166 to Richie, Jr. et al. and U.S. Patent No. 4,901,194 to Steinman et al., both of which are incorporated herein by reference in their entireties.

[0029] 2 is a flow chart illustrating an example method 200 for inactivating viable microorganisms using non-thermal plasma sterilization. The example method 200 is described below in conjunction with the example system 100 of FIG.

[0030] In block 202, the volume and / or area of a room (e.g., room 102) to be sterilized is determined. Sterilization can be continuous or discontinuous, and / or different portions of room 102 (e.g., sub-volumes 118, 120) may have different sterilization requirements. In some examples, a microbial reduction level (e.g., log-kill ratio) can be defined for room 102.

[0031] In block 204, the number and configuration of ion emitter modules are determined based on the volume and area of the room 102. For example, based on the volume and / or area of the room 102, the height of the room 102, the airflow velocity within the room 102, and / or the ionization capabilities of the ion emitter modules 104, the number of ion emitter modules 104 required to provide one or more ionization levels required to achieve a particular sterilization, volumetric ion coverage, and / or area ion coverage can be determined.

[0032] In block 206, the determined number of ion emitter modules 104 are installed in a determined configuration. For example, the ion emitter modules 104 are installed in the ceiling of the room 102 to provide the desired ionization. Installing the ion emitter modules 104 may further include connecting the ion emitter modules 104 to respective HVPSs 110.

[0033] In block 208, the ion emitter modules 104 are connected to one or more controller modules (e.g., the digital controllers 112, 114 of FIG. 1 ). For example, the ion emitter modules 104 can be coupled to the digital controllers 112, 114 via a bus, a point-to-point connection, a wireless connection, and / or any other connection. In some examples, a first subset of the ion emitter modules 104 is coupled to the digital controller 112 and is determined by the control capabilities of the digital controller 112. A second subset of the ion emitter modules 104 is coupled to the digital controller 114 (and is determined by the control capabilities of the digital controller 114).

[0034] In block 210, the ion emitter module 104 is configured with the connected controller modules 112, 114. For example, the ion emitter module 104 may be configured for one or more plasma generation modes (e.g., pulsed DC mode, steady state DC mode, standby mode, and / or any combination of modes), pulse intervals, and / or any other configurable aspects, at least some of which are described in U.S. Pat. No. 8,861,166 and U.S. Pat. No. 4,901,194.

[0035] In block 212, the example controller 112, 114 may determine whether microbial deactivation is required. In some examples, the controller 112, 114 determines whether ionization should occur, which may be based more generally on a schedule and / or one or more sensors indicating the sterilization level of the room 102. In some examples, microbial deactivation is continuous, and therefore, block 212 may be omitted.

[0036] If microbial inactivation is required (block 212), then in block 214, the controllers 112, 114 control the ion emitter module 104 to generate a non-thermal plasma within the room 102 to inactivate viable microorganisms within the room 102. For example, the ion emitter module 104 generates positive ions 122 and negative ions 124 to provide a substantially neutral charge within the room 102, while the positive ions 122 and / or negative ions 124 inactivate airborne and / or surface-borne microorganisms.

[0037] In the example method 200, blocks 212 and 214 repeat to generate a non-thermal plasma as appropriate to provide sterilization to the room 102.

[0038] Figure 3 is a flow chart illustrating an example method 300 for determining the number and configuration of ion emitter modules 104 of Figure 1. The example method 300 may be executed to implement block 204 of Figure 2 and may begin after executing block 202 of Figure 2.

[0039] If multiple ion densities are desired for different portions of a chamber (block 302), the volume, area, and ion density of each of the sub-volumes (e.g., sub-volumes 118, 120) of the chamber 102 are determined in block 304. In block 306, the number and configuration of ion emitter modules for the sub-volumes 118, 120 of the chamber 102 are determined based on the respective volumes, areas, and ion densities.

[0040] If multiple ion densities are not required for different parts of a room (e.g., the same ion density for the room 102 is acceptable) (block 302), then in block 308 the number and configuration of ion emitter modules is determined for the overall volume, area, and ion density of the room 102.

[0041] After determining the number and configuration of ion emitter modules, the example method 300 ends, and the example method 200 may resume at block 206.

[0042] The methods and systems may be embodied in hardware and / or a combination of i) hardware and ii) software and / or firmware. The methods and / or systems may be embodied in a centralized fashion in at least one computing system, or in a distributed fashion where different elements are spread across several interconnected computing systems. Any kind of computing system or other apparatus adapted to perform the methods described herein is suitable. A typical combination of hardware and software may include a general-purpose computing system, along with a program or other code that, when loaded and executed, controls the computing system to perform the methods described herein. Another typical embodiment may include one or more application-specific integrated circuits or chips. Some embodiments may include a non-transitory machine-readable (e.g., computer-readable) medium (e.g., flash memory, optical disk, magnetic storage disk, etc.) that stores one or more lines of code executable by a machine, thereby causing the machine to perform a process as described herein. As used herein, the term "non-transitory machine-readable medium" is defined to include all types of machine-readable storage media and to exclude propagating signals.

[0043] As used herein, the terms "circuit" and "circuitry" refer to physical electronic components (i.e., hardware) and any software and / or firmware ("code") that can comprise, be executed by, and / or otherwise be associated with hardware. As used herein, for example, a particular processor and memory can include a first "circuit" when executing a first line or lines of code, and can include a second "circuit" when executing a second line or lines of code. As used herein, "and / or" refers to any one or more of the items in the list connected by "and / or." As an example, "x and / or y" refers to any element of the triplet {(x), (y), (x, y)}. In other words, "x and / or y" means "one or both of x and y." As another example, "x, y, and / or z" means any element of the seven-element set {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}. In other words, "x, y, and / or z" means "one or more of x, y, and z." As used herein, the term "exemplary" means serving as a non-limiting example, instance, or illustration. As used herein, the term "for example" begins a list of one or more non-limiting examples, instances, or illustrations. As used herein, circuitry is "operable" to perform a function whenever it includes the necessary hardware and code (if either is necessary) to perform that function, regardless of whether implementation of that function is disabled or enabled (e.g., by a user-configurable setting, factory trim, etc.).

[0044] The above-cited patents and patent publications are incorporated herein by reference in their entireties. While the present method and / or system has been described with reference to certain specific embodiments, those skilled in the art will recognize that various modifications and equivalents may be substituted without departing from the scope of the present method and / or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the scope of the present disclosure. Therefore, the present method and / or system is not limited to the particular embodiments disclosed. Instead, the present method and / or system includes all embodiments falling within the scope of the appended claims, both literally and under the doctrine of equivalents. Some aspects of the disclosure are described below. [Aspect 1] 1. A method for inactivating viable microorganisms, comprising: Within a given volume, providing a plurality of ceiling-mounted, direct current (DC) or alternating current (AC), bipolar or steady-state ion emitter modules based on the geometry of the predetermined volume; and inactivating viable microorganisms by generating DC or AC, bipolar or steady-state non-thermal plasma (NTP) using said plurality of ceiling-mounted ion emitter modules, each equipped with a high voltage power supply (HVPS). [Aspect 2] 2. The method of claim 1, wherein the installing the plurality of ceiling-mounted ion emitter modules comprises arranging the plurality of ceiling-mounted ion emitter modules to have a module density within the predetermined volume based on a target ion density. [Aspect 3] 3. The method of claim 2, wherein the target ion density corresponds to a sub-volume within the predetermined volume. [Aspect 4] connecting the plurality of ceiling-mounted ion emitter modules to a controller module; 2. The method of embodiment 1, further comprising controlling the plurality of ceiling-mounted ion emitter modules with the controller module. [Aspect 5] The method of claim 1, wherein the generating of the non-thermal plasma includes controlling at least a portion of the plurality of ceiling-mounted ion emitter modules to generate the non-thermal plasma in at least one of a pulsed DC mode, a steady-state DC mode, or an AC mode. [Aspect 6] 2. The method of claim 1, wherein the installing the plurality of ceiling-mounted ion emitter modules includes providing the ceiling-mounted ion emitter modules with stainless steel shrouds that protect emitters of the ceiling-mounted ion emitter modules. [Aspect 7] 2. The method of claim 1, wherein the generating the non-thermal plasma comprises generating a non-thermal plasma having alternating polarity. [Aspect 8] 8. The method of claim 7, wherein the generating the non-thermal plasma comprises generating the non-thermal plasma at different plasma densities using different ones of the plurality of ceiling-mounted ion emitter modules. [Aspect 9] 2. The method of claim 1, wherein the generating the non-thermal plasma further comprises causing the non-thermal plasma to traverse the predetermined volume. [Aspect 10] 2. The method of claim 1, wherein the generation of the non-thermal plasma includes inactivating at least a threshold percentage of bacteria, spores, fungi, and viruses present in the predetermined space. [Aspect 11] 2. The method of claim 1, wherein the generating the non-thermal plasma comprises generating a neutral net charge. [Explanation of symbols]

[0045] 100 systems 102 rooms 104 Ion Emitter Module 106 Emitter 108 Emitter 110 HVPS example 112 Controller Module 114 Controller Module 116 Programming Devices 118 Partial volume 120 Partial volume 122 positive ions 124 negative ions

Claims

1. 1. A method for inactivating viable microorganisms, comprising: In one room with multiple sub-areas, installing a plurality of direct current (DC) or alternating current (AC), bipolar or steady state ceiling-mounted ion emitter modules arranged based on the geometry of the room such that the plurality of ceiling-mounted ion emitter modules have a module density within the room based on a target ion density; connecting the plurality of ceiling-mounted ion emitter modules to a controller module; generating a DC or AC, bipolar or steady-state non-thermal plasma (NTP) using said plurality of ceiling-mounted ion emitter modules, each equipped with a high voltage power supply (HVPS); controlling the plurality of ceiling-mounted ion emitter modules using the controller module; The method wherein the target ion density is determined for each of the plurality of sub-regions within the single chamber.

2. 10. The method of claim 1, wherein the generating the non-thermal plasma comprises controlling at least a portion of the plurality of ceiling-mounted ion emitter modules to generate the non-thermal plasma in at least one of a pulsed DC mode, a steady-state DC mode, or an AC mode.

3. 2. The method of claim 1, wherein the installing the plurality of ceiling-mounted ion emitter modules includes providing the ceiling-mounted ion emitter modules with stainless steel shrouds that protect emitters of the ceiling-mounted ion emitter modules.

4. The method of claim 1 , wherein said generating said non-thermal plasma comprises generating a non-thermal plasma having alternating polarity.

5. 5. The method of claim 4, wherein said generating said non-thermal plasma comprises generating said non-thermal plasma at different plasma densities using different ones of said plurality of ceiling-mounted ion emitter modules.

6. 2. The method of claim 1, wherein the generating of the non-thermal plasma comprises inactivating at least a respective threshold percentage of bacteria, spores, fungi, and viruses present within each of the plurality of sub-regions.

7. The method of claim 1 , wherein the generating the non-thermal plasma comprises generating a neutral net charge.

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