Assembly and Method for Decontaminating Objects

Abstract

The invention relates to an assembly and a method for completely sterilizing at least one object. For this purpose, a chamber is provided in which the object is sterilized. A plasma system for producing reactive species is associated with the chamber. A conveying means is arranged in such a way that a circulation mass flow leads through the plasma system and over the at least one object through the chamber and back to the conveying means. An outlet (8) is fluidically associated with the chamber such that an effective mass flow (8W) can be led out of the chamber.

Claims

1. An assembly for decontaminating or sterilizing at least one object, comprising a chamber in which the at least one object is placed and a plasma system which is fluidically connected with the chamber, the assembly comprising: a mixing chamber, which is arranged upstream of the plasma system and connected via a pipe to an inlet of a discharge chamber of the plasma system, such that an input mass flow can be supplied to the discharge chamber of the plasma system; a conveying means which is arranged in a second supply pipe from the chamber to the mixing chamber in order to guide a circulation mass flow from the chamber back to the mixing chamber; and a recirculation turnout provided between the plasma system and the chamber, wherein the recirculation turnout is fluidically connected with an outlet of the plasma system via a pipe, a first outlet of the recirculation turnout is fluidically connected with the circulation mass flow, and a second outlet of the recirculation turnout is fluidically connected with the chamber via a pipe.

2. The assembly according to claim 1, wherein a heat source and/or heat sink is associated with the plasma system and/or a heat source or heat sink is associated with the chamber.

3. The assembly according to claim 1, wherein a condensate separator is associated with the chamber and the second supply pipe leads from the condensate separator to the mixing chamber.

4. The assembly according to claim 1, wherein the mixing chamber is connected with the conveying means via a first supply pipe, and the mixing chamber is connected with at least one dosing unit via the second supply pipe.

5. The assembly according to claim 4, wherein a heat source and/or heat sink is assigned to the mixing chamber.

6. The assembly according to claim 1, wherein a control and measuring unit is provided, which is communicatively connected at least with a voltage source of the plasma system, the recirculation turnout, the chamber, the conveying means, the mixing chamber, the heat sources and/or heat sinks or the at least one dosing unit.

7. The assembly according to claim 1, wherein the plasma system comprises a discharge chamber, in which at least one piezoelectric transformer is provided which is connected to the voltage source of the plasma system for generating reactive species.

8. A method for decontaminating or sterilizing objects, comprising the following steps: charging a discharge chamber of a plasma system with a gas mixture from at least one mixing chamber via a pipe; igniting a discharge with the gas mixture in the discharge chamber of the plasma system; feeding an acting mass flow from the discharge chamber to a chamber via pipes; guiding a recirculation mass flow from the chamber to the mixing chamber with a conveying means in a second supply pipe, and feeding again the recirculation mass flow to the chamber via the discharge chamber of the plasma system, so that an acting mass flow leaving the discharge chamber has an increased concentration of reactive compounds or substances; feeding an output mass flow from the discharge chamber of the plasma system to a recirculation turnout, wherein the recirculation turnout divides the output mass flow into the acting mass flow and the recirculation mass flow; controlling at least one voltage source of the discharge chamber of the plasma system, the mixing chamber and the conveying means by means of a control and measuring unit for process control, and the control and measuring unit for process control collecting data at least from the discharge chamber of the plasma system, the mixing chamber and the conveying means, which data are used to control the process management, wherein the control and measuring unit also monitors and regulates the recirculation turnout.

9. The method according to claim 8, wherein the mixing chamber receives a predetermined mixture from at least one dosing unit and the recirculation mass flow from the conveying means via a second supply pipe.

10. The method according to claim 8, wherein the temperature in the mixing chamber, in the discharge chamber of the plasma system and the chamber is monitored and regulated by means of the control and measuring unit.

11. The method according to claim 8, wherein the discharge is ignited with the gas mixture supplied from the mixing chamber by means of at least one piezoelectric transformer in the discharge chamber of the plasma system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In the following, exemplary embodiments are intended to explain the invention and its advantages in more detail with reference to the accompanying figures. The size relationships in the figures do not always correspond to the real size relationships, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration. Reference is made to the accompanying drawings in which:

[0058] FIG. 1 shows a schematic view of an embodiment of the invention, wherein in the simplest case the discharge burns within the chamber with the object to be treated;

[0059] FIG. 2 shows a schematic view of a further embodiment of the invention, the plasma system being designed as a flow-through reactor;

[0060] FIG. 3 shows a schematic view of yet another embodiment of the invention, the plasma system being designed as a flow-through reactor and the chamber being spatially separated from the plasma system; and

[0061] FIG. 4 shows a schematic view of a flow chart for carrying out a method for decontaminating or sterilizing at least one object.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0062] Identical reference numerals are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numerals are shown in the individual figures which are necessary for the description of the respective figures.

[0063] FIG. 1 shows an assembly 1 for decontaminating or sterilizing at least one object 4. In the simplest case, assembly 1, as indicated here, may consist of a chamber 6 in which a discharge 9 is burning. The discharge 9 burns in a plasma system 11 which is arranged inside chamber 6. The at least one object 4 to be sterilized is likewise located in chamber 6. An inlet 7 is associated with chamber 6, via which inlet 7 an inlet mass flow 7E can be brought into chamber 6. Furthermore, an outlet 8 is associated with chamber 6, by means of which outlet 8 an effective mass flow 8W can be transported away from chamber 6. A circulation mass flow 19 is formed within chamber 6, which flows over the plasma system 11 and the object 4 to be sterilized. The circulation mass flow 19 can be set in chamber 6 by means of a conveying means 12. The conveying means 12 may be a pump or a circulating air fan. The circulation mass flow 19 is always guided over the plasma system 11 by conveying means 12 in order to increase the proportions of reactive compounds or substances for the decontamination or sterilization of object 4. Likewise, according to a further embodiment, the circulation mass flow 19 can be maintained via convection. For this purpose, the interior of chamber 6 is designed in such a way that uniform convection is formed. By means of the convection or the conveying means 12 it is ensured that a circulation mass flow 19 with reactive compounds or substances not only reaches the object 4 to be decontaminated or sterilized, but also increases the proportion of reactive compounds or substances per unit volume. According to the structural conditions, the plasma system 11 has a certain length along which the circulation mass flow 19 can be provided with reactive substances. The concentration that can be achieved in a single cycle through the plasma system 11 is not sufficient to carry out an effective decontamination of the objects 4. The concentration of reactive compounds or substances can be increased by means of multiple cycles through the plasma system 11.

[0064] Within a certain time, an equilibrium of the concentrations of the reactive compounds or substances is established if the boundary conditions are fixed. If a liquid or aqueous phase and a gaseous phase (air) coexist in chamber 6, the pH value in the aqueous phase falls into the acidic range and the concentration of hydrogen peroxide increases up to a given equilibrium value. By supplying air and water in a suitable ratio via inlet 7, chamber 6 (closed reactor) becomes a flow-through reactor.

[0065] FIG. 2 shows a schematic view of a further embodiment of the invention, the plasma system 11 being designed as a flow-through reactor and the plasma system 11 being spatially separated from chamber 6 (not shown here). At least one mixture of different initial fluid and gaseous components can be fed to plasma system 11 of the assembly 1. In the illustration described in FIG. 2, a single dosing unit 23.sub.1 is provided, which is connected to a mixing chamber 16 via a first supply pipe 25. Furthermore, the mixing chamber 16 is connected to the conveying means 12 via a second supply pipe 27. Although only one single dosing unit 23.sub.1 is shown in the embodiment shown here, this should not be interpreted as a restriction of the invention. As can be seen from the embodiment shown in FIG. 3, more than one dosing unit 23.sub.1, 23.sub.2, . . . 23.sub.N may be associated with mixing chamber 16.

[0066] The plasma system 11 consists of a voltage source 2 which is connected to a discharge chamber 17. The discharge chamber 17 is connected to a ground connection 3. A discharge zone 18, within which the reactive species are formed, is formed in the discharge chamber 17. The length L of the discharge chamber 17 is decisive for the formation of the proportion or the concentration of the reactive compounds or substances of the mixture leaving the discharge chamber 17.

[0067] From the mixing chamber 16, a gas or substance mixture can be fed via a pipe 24 to an inlet 7 of the plasma system 11 or the discharge chamber 17. A gas discharge ignites in the discharge zone 18 of discharge chamber 17. Depending on the intensity of the gas discharge, the gas composition and other process parameters such as flow rate, temperature or pressure, a constant composition of products (reactive compounds or substances) with different lifespans and reactivity that act on the object 4 is created.

[0068] The discharge chamber 17 of plasma system 11 is followed by a recirculation turnout 5. The recirculation turnout 5 is fluidically connected to an outlet 13 of the discharge chamber 17 of plasma system 11. A first outlet 14 of recirculation turnout 5 is fluidically connected to the circulation mass flow 19. A second outlet 15 of recirculation turnout 5 is fluidically connected via a pipe 28 to chamber 6 (not shown here). By returning the circulation mass flow 19 into discharge chamber 17 of plasma system 11, the concentration of the reactive compounds or substances can be increased step by step.

[0069] FIG. 3 shows a schematic view of yet another embodiment of the invention. Discharge chamber 17 of plasma system 11 is designed as a flow-through reactor. Chamber 6 for the treatment of objects 4 is spatially separated from discharge chamber 17 of plasma system 11. From chamber 6 with object 4, an effective mass flow 8W is emitted to the environment via outlet 8, and reactive compounds or substances flow through chamber 6.

[0070] In the embodiment shown here, three dosing units 23.sub.1, 23.sub.2 and 23.sub.3 are connected to mixing chamber 16. The temperature in mixing chamber 16 can be set via a heat sink and/or heat source 30. The input mass flow 7E is fed from mixing chamber 16 to inlet 7 of discharge chamber 17 of plasma system 11. Likewise, the plasma process (generating plasma in discharge chamber 17) itself may be a heat source 30 that is used to vaporize a liquid component, which is supplied by at least one of the dosing units 23.sub.1, 23.sub.2, and 23.sub.3, in mixing chamber 16. The evaporation process in mixing chamber 16 would then be a heat sink 30. This relationship has the advantage that a liquid medium (for example, water or condensate from the recirculation process) can be evaporated without additional heating power.

[0071] Typically, the discharge in discharge chamber 17 of plasma system 11 is generated by an electrical excitation that is fed via the voltage source 2 of plasma system 11. For process control, the discharge chamber 17 can be heated or cooled by means of a heat source and/or heat sink 20. In particular, the plasma process in discharge chamber 17 may itself be a heat source 20 which is used to vaporize a liquid component. The evaporation process would then be a heat sink 20. This relationship has the advantage that discharge chamber 17 is cooled by evaporation and a liquid medium (for example, water) can be evaporated without additional heating power. The outlet 13 of discharge chamber 17 of plasma system 11 is fed to the recirculation turnout 5 via a pipe 26. A recirculation mass flow 19 can be fed back from chamber 6 and recirculation turnout 5 to mixing chamber 16 via a second pipe 27 and the conveying means 12.

[0072] The recirculation mass flow 19 and thus the recirculation ratio depend on the power of conveying means 12, the setting of recirculation turnout 5 and the settings on dosing units 23.sub.1, 23.sub.2 and 23.sub.3. Second outlet 15 of recirculation turnout 5 is fluidically connected via a pipe 28 to chamber 6 in which the object 4 to be treated is located. Chamber 6 can optionally be kept at a constant temperature via a heat source and/or heat sink 21. If necessary, part of the active gas and the condensate can be introduced into the circulation mass flow 19 from chamber 6 via a condensate separator 22. The chamber 6 flows through the outlet 8 to the environment.

[0073] A control and measurement unit 50 is provided for process control, which may be communicatively (wired and/or wireless) connected with the elements of assembly 1, such as voltage source 2, recirculation turnout 5, chamber 6, plasma system 11, conveying means 12, mixing chamber 16, heat sources and/or heat sinks 20, 21, or the at least one dosing unit 23.sub.1, 23.sub.2, . . . , 23.sub.N. It is obvious to those skilled in the art that the above list is not exhaustive. Elements of assembly 1 can be switched on or off as required.

[0074] A flow chart of an embodiment of the method according to the invention is shown in FIG. 4. According to the invention, a plasma system 11 or a discharge chamber 17 (flow-through reactor) is charged with at least one gas mixture or mixture from the at least one mixing chamber 16. A discharge is ignited in the discharge chamber 17 of plasma system 11. Depending on the intensity of the gas discharge, the gas composition and other process parameters, such as throughput rate (flow-through rate, flow rate), temperature or pressure results in a constant composition of compounds or substances (products) with different lifetimes and reactivity.

[0075] A given mixture of different initial fluid and gaseous components from different dosing units 23.sub.1, 23.sub.2, . . . , 23.sub.N is prepared with a mixing chamber 16. The temperature in the mixing chamber 16 can be set via a heat sink and/or heat source 30. The input mass flow 7E is fed into discharge chamber 17 of plasma system 11. In the discharge chamber 17 of plasma system 11, the discharges burn in the discharge zone 18. The discharge is typically generated by an electrical excitation that is fed via the voltage source 2. The plasma system 11 or the discharge chamber 17 can be heated or cooled for process control. The electrical discharge is preferably ignited in the discharge chamber 17 by means of at least one piezoelectric transformer 40. The functioning of a piezoelectric transformer is well known and does not need to be explained again here.

[0076] The output mass flow 13A is returned to mixing chamber 16 via recirculation turnout 5 and partly via a conveying means 12. The recirculation mass flow 19 and thus the recirculation ratio depends on the power of the conveying means 12, the setting of the recirculation turnout 5 and the settings of the dosing units 23.sub.1, 23.sub.2, . . . , 23.sub.N. The acting mass flow 15W enters a chamber 6 from the second outlet 15 of recirculation turnout 5, in which chamber 6 the object 4 to be treated is located. The chamber 6 can optionally be kept at a constant temperature via a heat source and/or heat sink 22. If necessary, part of the active gas and the condensate can be introduced into the recirculation mass flow 19 via a condensate separator 22. An effective mass flow 8W can be emitted to the environment via an outlet 8.

[0077] The control and measuring unit 50 and the principle of recirculation can significantly increase the yield of the reactive species generated in the discharge chamber 17 of plasma system 11. The composition of the mixture can be adjusted over a wide range by means of mixing chamber 16. When a dielectric barrier discharge (for example, piezoelectric transformer 40) is used as the discharge type, the power of the dielectric barrier discharge device can be kept low.

[0078] The invention has been described in terms of preferred embodiments. It will be understood by those skilled in the art that changes and modifications of the invention may be made without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

[0079] 1 Assembly [0080] 2 Voltage source [0081] 3 Ground connection [0082] 4 Object [0083] 5 Recirculation turnout [0084] 6 Chamber [0085] 7 Inlet [0086] 7E Input mass flow [0087] 8 Outlet [0088] 8W Effective mass flow [0089] 9 Discharge [0090] 11 Plasma system [0091] 12 Conveying means, pumping device [0092] 13 Outlet [0093] 13A Output mass flow [0094] 14 First outlet [0095] 15 Second outlet [0096] 15W Acting mass flow [0097] 16 Mixing chamber [0098] 17 Discharge chamber [0099] 18 Discharge zone [0100] 19 Circulation mass flow, recirculation mass flow [0101] 20 Heat source, heat sink [0102] 21 Heat source, heat sink [0103] 22 Condensate separator [0104] 23.sub.1, 23.sub.2, . . . , 23.sub.N Dosing unit [0105] 24 Pipe [0106] 25 First supply pipe [0107] 26 Pipe [0108] 27 Second supply pipe [0109] 28 Pipe [0110] 30 Heat sink and/or heat source [0111] 40 Piezoelectric transformer [0112] 50 Control and measuring unit [0113] L Length