Control device for controlling operating efficiency of irradiation beam emission device and method for controlling operating efficiency of said irradiation beam emission device
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2026-03-10
Smart Images
Figure CN121646816A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a control device and method for controlling the operating efficiency of an irradiation beam emitting device, so as to allow for diagnostics of the device.
[0002] This irradiation beam emitting device can be used in particular for sterilization devices, such as for sterilizing materials (especially packaging materials or pharmaceutical materials with multi-layered structures). Background Technology
[0003] The following section relates to the field of sterilization technology for packaging materials; it should be understood that the present invention is also applicable to the sterilization of other materials using irradiation beam emitting equipment.
[0004] Many liquid or pourable foods, such as fruit juice, UHT (ultra-high temperature) milk, wine, and ketchup, are packaged and sold using sterilized packaging materials.
[0005] This packaging material has a multi-layer structure, including a base layer (such as paper or cardboard) and two sides covered with heat-sealable plastic material layers (such as polyethylene).
[0006] This type of packaging is typically produced on fully automated packaging equipment. The equipment feeds and sterilizes rolls of packaging material, then forms them into tubes, and aseptically fills pre-sterilized / sterilized pourable products before forming individually sealed packages.
[0007] Therefore, a typical automated packaging unit also includes a corresponding sterilization unit for sterilizing the packaging material rolls before forming and filling pre-sterilized / sterilized pourable products.
[0008] Figure 1 illustrates a typical structure of such a packaging sterilization apparatus, which includes a first irradiation beam emitting device for sterilizing a first side of the packaging material; and a second irradiation beam emitting device for sterilizing a second side of the packaging material (opposite to the first side).
[0009] Each irradiation beam emitting device includes a main isolation housing, the internal space of which defines a vacuum chamber filled with vacuum gas and an exit window. Within the vacuum chamber, an irradiation transmission source is positioned, configured to generate an electron beam and guide it out of the vacuum chamber through the exit window, directing it toward one face of the packaging material roll.
[0010] Known sterilization devices must maintain the continuous optimal operation of the irradiation beam emitting equipment.
[0011] In fact, the sterilization effect is closely related to the dose (i.e., the energy emitted).
[0012] The vacuum pressure in the vacuum chamber of this irradiation beam emission device is closely related to the emission energy of the electron beam, and thus to the dose of the emission energy.
[0013] Therefore, maintaining an appropriate vacuum pressure inside the vacuum chamber is crucial for the optimal performance and operation of the irradiation beam emission equipment.
[0014] In fact, vacuum pressure directly affects the trajectory and behavior of the emitted electron beam during irradiation.
[0015] Specifically, a controlled vacuum environment helps minimize the scattering and collisions of electrons with gas molecules present in the chamber. These interactions significantly alter the path and energy distribution of the electron beam, thus affecting the efficiency and precision of the irradiation process.
[0016] Maintaining a suitable low vacuum pressure inside the vacuum chamber of an irradiation beam emission device reduces the likelihood of electron-gas molecule interactions. This allows for more precise control of electron beam emission, ensuring the stability and predictability of its trajectory. Furthermore, precisely controlled vacuum pressure inside the chamber helps minimize adverse effects such as electron deflection, beam divergence, or energy loss, which could impair the intended irradiation effect.
[0017] Therefore, the vacuum pressure of the vacuum chamber plays a crucial role in promoting electron beam emission with optimal characteristics, ultimately affecting the performance and efficiency of the irradiation beam emission equipment.
[0018] The industry urgently needs a control device to easily, quickly, and accurately monitor the operational efficiency of sterilization units that include irradiation beam emission equipment. Summary of the Invention
[0019] Therefore, the object of the present invention is to solve the above-mentioned problems by providing an apparatus and control method for an irradiation beam emitting device, which can easily, quickly and accurately monitor the status of the irradiation beam emitting device.
[0020] Furthermore, the object of the present invention is to provide an apparatus and control method for checking the status of an irradiation beam emitting device, so as to achieve extremely simple, rapid and accurate monitoring of the pressure status of the irradiation beam emitting device.
[0021] For the purposes described above, the technical features of the present invention can be clearly seen from the contents of the appended claims. Attached Figure Description
[0022] The advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, which are merely exemplary and not limiting embodiments, wherein: Figure 1 schematically illustrates a sterilization apparatus according to the prior art, which utilizes the control device described in this invention; Figure 2 shows, in cross-sectional view, the irradiation beam emitting device integrated in the sterilization apparatus shown in Figure 1, which utilizes the control device described in this invention; Figure 3 shows some components of the irradiation beam emitting device shown in Figure 2 in the form of a schematic cross-sectional view; Figure 4 shows the irradiation beam emitting device shown in Figure 2 in perspective view; Figure 5 shows, in schematic cross-sectional form, the control device of the present invention applied to the irradiation beam emitting device shown in Figure 2; Figure 6 shows a flowchart of the control method according to the present invention in schematic form; Figure 7 depicts a schematic diagram illustrating the interrelationships among various electrical characteristics upon which the control method of the present invention is based.
[0023] Detailed Implementation Plan The present invention relates to a control (diagnosis or monitoring) device 1 for controlling the operating efficiency of an irradiation beam emitting device 2.
[0024] Preferably, but not limited to, the control device 1 according to the invention is applied to the irradiation beam emitting device 2 of the sterilization apparatus 3 for sterilizing (packaging) material PM.
[0025] More specifically, according to a non-limiting example, the packaging material PM is in roll form and is fed into the sterilization device 3 by a known method (not shown in the figure).
[0026] According to the configuration shown in Figure 1, the sterilization device 3 preferably includes a first irradiation beam emitting device 2 and a second irradiation beam emitting device 2.
[0027] For the sake of simplicity, only the single irradiation beam emitting device 2 will be mentioned below, but without loss of generality; it will be understood that the irradiation beam emitting device 2 can be used in a variety of devices for sterilization purposes.
[0028] The irradiation beam emitting device 2 includes a filament 4, which is configured to emit electrons EB via the thermionic effect when heated.
[0029] The irradiation beam emitting device 2 also includes a first conductor 6 (hereinafter referred to as the first conductor 6) and a second conductor 5 (hereinafter referred to as the second conductor 5). Preferably, the first conductor 6 is one of the cathode or gate of the irradiation beam emitting device 2, and the second conductor 5 is the other of the gate or cathode of the irradiation beam emitting device 2. In the illustrated embodiment, the first conductor 6 is the gate of the irradiation beam emitting device 2, and the second conductor 5 is the cathode of the irradiation beam emitting device 2.
[0030] The first conductor 5 is electrically insulated from the second conductor 6.
[0031] The irradiation beam emitting device 2 also includes a housing 14 that surrounds the vacuum chamber 13. The housing 14 is typically made of ceramic or similar material to ensure voltage isolation between the exterior and the components inside the vacuum chamber 13 (i.e., the filament 4, the first conductor 6, and the second conductor 5 located within the vacuum chamber 13).
[0032] Please note that, according to the embodiment not shown in the figure, one of the first conductor 6 or the second conductor 5 may be the housing 14.
[0033] It should be emphasized that the arrangement of the first conductor 6 or the second conductor 5 is such that it surrounds a certain volume of gas.
[0034] This gas (which will be explained in more detail later) is ionized by electrons emitted by filament 4.
[0035] According to the present invention, the control device 1 includes a power supply 9 connected (e.g., directly or indirectly) to the filament 4, the first conductor 6 and the second conductor 5 to supply power to all of them and to apply a predetermined voltage difference to the first conductor 6 and the second conductor 5, thereby defining an electric field between the first conductor 6 and the second conductor 5.
[0036] The term "power supply" refers to any source of electricity capable of regulating the voltage and / or current of one or more outputs.
[0037] Power supply 9 defines an electrical source.
[0038] The power supply 9 is configured to be connected (e.g., directly or indirectly) to the power grid, or alternatively, equipped with a battery for power supply. It should be noted that, as shown in Figure 5, the power supply 9 may include multiple power supply units (9A, 9B, 9C) to supply power to the filament 4, the first conductor 6, and the second conductor 5, respectively. For example, the power supply 9 may include a first power supply unit 9A for supplying power to the filament 4; a second power supply unit 9B for supplying power to the first conductor 6; and a third power supply unit 9C for supplying power to the second conductor 5.
[0039] The term “supply power” indicates that the power supply unit (9A, 9B, 9C) is configured to regulate voltage and / or current in order to provide energy to the components connected thereto (filament 4, first conductor 6, or second conductor 5).
[0040] According to one aspect, the first power supply unit 9A is a power supply configured to apply a predetermined and adjustable current to the filament 4 when connected to it.
[0041] Preferably, the first power supply unit 9A can be connected to the filament 4 via a pair of wires, as shown in FIG5, with the wires indicated by reference numerals 19B and 19A (ground).
[0042] The connection between the power supply 9 and the electrical components (filament 4, first conductor 6 or second conductor 5) of the irradiation beam emitting device 2 will then be described in more detail.
[0043] In one aspect, the second power supply unit 9B is configured to apply a predetermined and adjustable first (preferably negative) voltage to the first conductor 6 when connected to the first conductor 6.
[0044] Preferably, the second power supply unit 9B can be connected to the first conductor 6 via a pair of wires, which are indicated in FIG. 5 by reference numerals 19C and 19A (ground).
[0045] According to one aspect, the third power supply unit 9C is configured to apply a predetermined and adjustable second (preferably positive) voltage to the second conductor 5 when connected to the second conductor 5.
[0046] The experimental tests conducted by the applicant show that when the voltage of the second conductor 5 is positive (greater than zero) and the voltage of the first conductor 6 is negative (less than zero), the optimal configuration can be achieved, thereby minimizing the error noise of the derived state parameters and achieving the most accurate diagnosis.
[0047] In particular, experimental tests show that the optimal configuration can be achieved when the cathode (as the second conductor 5) is polarized as the positive electrode and the gate (as the first conductor 6) is polarized as the negative electrode.
[0048] Therefore, in the preferred configuration, the voltage signs of the first conductor and the second conductor (5, 6) are opposite, which means that one of the predetermined voltages on the first conductor 6 and the second conductor 5 is positive, while the other of the predetermined voltages on the second conductor 5 and the first conductor 6 is negative.
[0049] Specifically, electrons emitted by filament 4 are attracted toward the corresponding conductor (second conductor 5 or first conductor 6) to which a positive voltage is applied, while positive ions generated during gas ionization are attracted to the corresponding element (first conductor 6 or second conductor 5) to which a negative voltage is applied.
[0050] Preferably, the third power supply unit 9C can be connected to the second conductor 5 via a pair of wires, which are indicated by reference numerals 19D and 19A (ground) in FIG. 5.
[0051] According to the present invention, the control device 1 further includes a sensing unit 11 comprising: at least one first sensor 7 configured to detect at least one electrical parameter related to the current flowing through the gate 6, the current being defined as an ionization current IC; and a second sensor 8 configured to detect at least one electrical parameter related to the current flowing through the second conductor 5, the current being defined as an emission current EC. Specifically, the emission current is generated by electrons emitted by the filament 4. Specifically, the ionization current is formed by positive ions generated during the ionization of the gas.
[0052] Preferably, the first sensor 7 and the second sensor 8 are current sensors.
[0053] According to the present invention, the control device 1 includes a control unit 10 coupled to a sensing unit 11 for receiving detected electrical parameters.
[0054] The control unit 10 is also connected (e.g., directly or indirectly) to the power supply 9 to regulate one or more electrical parameters of the power supply 9 (output voltage, output current, etc.).
[0055] In addition, the control device 1 includes a housing 20, defined for example by a box of any shape, which houses the electrical components of the control device 1, such as the power supply 9, the sensing unit 11 and the control unit 10 described above.
[0056] The housing 20 preferably includes at least one handle.
[0057] In addition, the housing 20 is configured to be portable.
[0058] In practice, when it is necessary to diagnose or monitor the operating efficiency of the irradiation beam emitting device 2, the control device 1 can be conveniently moved to the vicinity of the irradiation beam emitting device 2.
[0059] According to the present invention, the control unit 10 is configured to execute a main control mode F1 for the state of the irradiation beam emitting device 2, the mode including: Adjust the power supply 9 to apply a predetermined current to the filament 4 to emit electrons; Adjust the power supply 9 to apply a predetermined (preferably positive) voltage to the second conductor 5; Adjust the power supply 9 to apply a predetermined (preferably negative) voltage to the first conductor 6; Based on the detected electrical parameters related to the ionization current IC and the detected electrical parameters related to the emission current EC, at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 is derived.
[0060] Please note that when the control unit 10 adjusts the power supply 9 to apply a predetermined (preferably negative) voltage to the first conductor 6 and adjusts the power supply 9 to apply a predetermined (preferably positive) voltage to the second conductor 5, a positive electric field is defined between the second conductor 5 and the first conductor 6.
[0061] Preferably, the control unit 10 regulates the power supply 9 to apply a voltage of more than 200V to the second conductor 5 (more preferably, between 200V and 1500V).
[0062] Preferably, the control unit 10 adjusts the power supply 9, and the voltage applied to the first conductor 6 is between -25V and -150V.
[0063] The following will describe in more detail how the configuration of the control unit 10 achieves the specific advantages of the present invention, thereby solving the previously defined technical problems.
[0064] When an electron stream passes through a low-pressure gas medium, collisions occur between electrons and gas molecules. In the presence of sufficient electron energy, the gas molecules ionize, resulting in an ionization current. The magnitude of this ionization current is directly affected by the vacuum pressure of the vacuum chamber 13, and increases with increasing pressure.
[0065] According to the present invention, the filament 4 is heated to a temperature sufficient for thermionic emission under the action of the filament current FC.
[0066] By applying a positive potential (voltage) to the second conductor 5, electrons emitted by the filament 4 are attracted by the second conductor 5 and subsequently accelerated to an energy sufficient to ionize gas molecules within the vacuum chamber 13 of the irradiation beam emitting device 2.
[0067] The original electrons (i.e., the electrons emitted by filament 4) and the electrons produced during ionization both travel along their paths toward the second conductor 5, where they are eventually absorbed. Conversely, the positively charged ions produced by the collisions are accelerated toward the first conductor 6, which has a negative potential (i.e., voltage).
[0068] As will be discussed in more detail later, the applicant discovered through experiments that the relationship between the emission current (EC, defined as electrons moving toward the second conductor 5) and the ionization current (IC, defined as ions moving toward the first conductor 6) depends on the magnitude of the vacuum pressure in the vacuum chamber 13.
[0069] The graphs (C1, C2, C3, C4) shown in Figure 7 illustrate the relationship between the emission current EC and the ionization current IC under different vacuum chamber pressures in vacuum chamber 13. It should be noted that curve C1 corresponds to a pressure of 1e^5 mbar, curve C2 corresponds to a pressure of 1e^6 mbar, and curves C3 and C4 correspond to pressures of 1e^7 mbar and 1e^8 mbar, respectively. The graphs in Figure 7 were obtained by the applicant through experiments, during which the applicant tested various irradiation beam emitting devices 2 with different internal vacuum pressures in vacuum chamber 13.
[0070] In particular, the applicant experimentally observed that, for a predetermined emission current EC, the ionization current IC increases with the increase of the internal pressure of the vacuum chamber 13.
[0071] In other words, the applicant experimentally observed that the slope (angular coefficient) of the linear relationship obtained by interpolating the experimental points (EC; IC) of the emission current EC and ionization current IC measured by the sensing unit 11 increases with the increase of the internal pressure of the vacuum chamber 13.
[0072] Therefore, it can be concluded that the ratio of emission current EC to ionization current IC is directly proportional to the vacuum pressure inside vacuum chamber 13: the higher the vacuum pressure, the greater the ratio.
[0073] The parameter representing the operating efficiency of the radiation beam emitting device 2 can be one of the following: The ratio of emission current EC to ionization current IC; The pressure inside vacuum chamber 13; The value of the ionization current IC at the predetermined emission current EC value.
[0074] Please note that the parameter representing the operating efficiency of the irradiation beam emitting device 2 is a parameter whose value is directly or indirectly related to the vacuum pressure of the vacuum chamber 13.
[0075] It should be noted that the first sensor 7 is specifically designed to measure the ionization current IC flowing through the first conductor 6 due to the voltage applied by the power supply 9 (especially the second power supply unit 9B).
[0076] Conversely, the second sensor 8 is specifically designed to measure the emission current EC flowing through the second conductor 5 due to the voltage applied by the power supply 9 (especially the third power supply unit 9C).
[0077] Preferably, the voltage of the housing 14 is 0V (corresponding to the ground voltage).
[0078] Furthermore, when current is applied to filament 4, its voltage (at least at one point therein or at least one point of its power supply conductor) is 0V.
[0079] According to one aspect, the control unit 10 is configured to: At different times, the power supply 9 applies multiple predetermined current values FC to the filament 4, thereby generating multiple different electron beam emissions. The state parameters are derived based on the electrical parameters related to the ionization current IC and the electrical parameters related to the emission current EC detected by the sensing unit 11 under different filament 4 current values.
[0080] It can be seen that by changing the filament current FC, different emission current EC and ionization current IC can be obtained, thereby allowing multiple different emission current EC / ionization current IC pairs (preferably, at least two pairs).
[0081] Preferably, the control unit 10 is configured to derive a predetermined mathematical relationship between detected emission current / ionization current pairs (also known as EC / IC current pairs), such as determining the slope or angle coefficient that correlates (preferably interpolates) the linear relationship of the EC / IC current pairs.
[0082] As previously stated, the slope or angle coefficient of the linear relationship associated (preferably interpolated) of the EC / IC current pair is related to or proportional to the vacuum pressure of the gas inside the vacuum chamber 13.
[0083] In other words, the derived slope or angle coefficient measurement indicates the gas vacuum pressure inside the vacuum chamber 13, representing the state of the irradiation beam emitting device 2.
[0084] Please note that the control unit 10 is preferably configured to adjust the filament current FC value in predetermined steps, each step being between 0.05A and 0.2A, starting from the first lower value of the filament current (preferably between 3A and 7A).
[0085] It can be observed that, under normal circumstances, for these filament current FC values, the emission current EC is lower than the predetermined current value, preferably 20mA.
[0086] According to another aspect, the control unit 10 is configured to derive at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 based on the detected electrical parameters related to the ionization current IC and the detected electrical parameters related to the emission current EC, at a predetermined high emission current EC value (preferably between 10mA and 30mA).
[0087] In other words, based on this aspect, it is not necessary to obtain the value pair of current EC / IC; it is sufficient to detect the single value of ionization current IC under a predetermined emission current EC value.
[0088] It is understood that a predetermined emission current EC value can be obtained by appropriately driving or setting the filament current (FC) value through the control unit 10.
[0089] According to another aspect, the control device 1 includes a (permanent, i.e., non-volatile) memory 12 connected (e.g., directly or indirectly, wirelessly or wired) or integrated into the control unit 10 for storing at least one reference parameter (or preferably, multiple reference parameters).
[0090] Accordingly, the control unit 10 is configured to derive at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 based on detected electrical parameters related to the ionization current IC and the emission current EC, as well as at least one reference parameter stored in the memory 12.
[0091] Please note that the detected electrical parameters related to the ionization current IC and the emission current EC are compared with at least one reference parameter stored in memory 12.
[0092] According to another aspect, the at least one reference parameter defines the relationship between the ionization current IC and the emission current EC relative to the vacuum pressure inside the vacuum chamber 13 of the irradiation beam emitting device 2.
[0093] Preferably, as described above in conjunction with Figure 7, the at least one reference parameter includes at least one value (preferably multiple values) that defines a mathematical linear relationship (e.g., slope) between the ionization current IC and the emission current EC relative to different vacuum pressures inside the vacuum chamber 13 of the irradiation beam emitting device 2.
[0094] Also note that control device 1 has a user interface 15.
[0095] User interface 15 is connected to control unit 10 and is used to send user commands and / or receive data from control unit 10.
[0096] Furthermore, preferably, the user interface 15 is configured to display data received from the control unit 10.
[0097] Preferably, the user interface 15 includes a screen.
[0098] Preferably, the user interface 15 includes buttons that the user can activate to send commands.
[0099] In addition, the control device 1 includes a communication module 16, which is configured to transmit and / or receive data.
[0100] According to one aspect, the communication module 16 is preferably connected to the control unit 10 to retrieve data from the control unit 10 and transmit such data, which includes, for example, one or more of the following: electrical parameter values detected by the sensing unit 11, status parameters indicating the operating efficiency of the irradiation beam emitting device 2, settings of the power supply 9, etc.
[0101] Other aspects of the invention will be described below, which constitute optional features and have the advantage of increasing the potential and overall reliability of the control device 1, enabling it to perform additional diagnostic checks and identify other failure modes of the irradiation beam emitting device 2.
[0102] It should be noted that the execution time intervals of these additional control modes that control device 1 can implement are different from those previously described (the previously described mode corresponds to the main control mode F1 shown in Figure 6).
[0103] In the following text, when introducing additional control modes, reference will be made explicitly to the flowchart shown in Figure 6 for explanation within the context of Figure 6.
[0104] However, it should be noted that although Figure 6 describes the sequential implementation scheme of these additional control modes according to the flowchart shown, this does not preclude the possibility that these additional control modes can be executed independently, or even executed according to different sequential implementation schemes. In other words, the control unit 10 can be configured to implement one or more control modes, in addition to the core main control mode F1 of this invention, as described below.
[0105] According to another aspect, the sensing unit 11 includes a third sensor 18, which is configured to detect electrical parameters related to the voltage applied to the filament 4.
[0106] It is worth noting that the presence of this additional third sensor 18 enables the implementation of the further control mode F2 as described below.
[0107] According to this further control mode F2, the control unit 10 is configured as follows: Adjust the power supply 9 to apply multiple different predetermined currents to the filament 4, these currents being defined as filament current FC; Based on the electrical parameters related to the voltage applied to the filament 4 detected relative to the filament current FC, at least one state parameter of the filament 4 is derived, which represents the operating efficiency of the filament 4 of the irradiation beam emitting device 2.
[0108] According to the control mode F2, the control unit 10 is configured to regulate the power supply 9 so that the voltage at the second conductor 5 and the first conductor 6 is zero, i.e., 0V.
[0109] Preferably, according to the control mode F2, the control unit 10 is configured to adjust the power supply 9 to increase the filament current FC in predetermined steps (preferably within the range of 0.05A to 0.2A) until a predetermined high filament current FC value (preferably within the range of 4A to 6A) is reached.
[0110] Preferably, the control unit 10 is configured to detect the voltage of the filament 4 at the predetermined high filament current FC value via the third sensor 18, and to compare the voltage of the filament 4 detected at the predetermined high filament current FC value.
[0111] More generally, regardless of the details of the implementation of the additional control mode F2, it can be observed that the control mode F2 is able to determine whether the pressure inside the vacuum chamber 13 is higher than a predetermined value.
[0112] In fact, if the filament voltage FC detected by the third sensor 18 is too high under the predetermined filament current FC (corresponding to condition F2B in Figure 6), it indicates that the pressure inside the vacuum chamber 13 is basically equal to the ambient pressure, which means that there is no vacuum inside the vacuum chamber 13.
[0113] Conversely, if the filament voltage FC detected by the third sensor 18 is equal to or lower than a predetermined value under a predetermined filament current FC (corresponding to condition F2A in Figure 6), it indicates that the pressure inside the vacuum chamber 13 is within the optimal operating range of the irradiation beam emitting device 2.
[0114] Therefore, the control unit 10 is further configured to derive a vacuum pressure indication within the vacuum chamber 13 of the irradiation beam emitting device 2 based on the derived state parameters of the filament 4, and in particular, to derive whether the vacuum pressure is equal to the ambient pressure.
[0115] Please note that this control mode F2 allows you to check the status of filament 4.
[0116] Preferably, according to one aspect, the control unit 10 is configured to execute control mode F2 before the main control mode F1.
[0117] The additional control mode F3, which corresponds to the rectangle F3 shown in Figure 6, will be described below.
[0118] According to the additional control mode F3, the control unit 10 is configured as follows: Adjust the power supply 9 to apply a predetermined (preferably negative) voltage to the first conductor 6; Adjust the power supply 9 to apply multiple different predetermined (preferably positive) voltages to the second conductor 5; Based on the detected electrical parameters related to the ionization current IC and the parameters related to the emission current EC, at least one state parameter of the first conductor 6-second conductor 5 is derived, which represents the operating efficiency of the first conductor 6-second conductor 5 combination.
[0119] According to one implementation of the above-mentioned operating mode F3, the control unit 10 is configured to regulate the power supply 9 to apply a predetermined (negative) voltage to the first conductor 6, the voltage range being -80V to -150V.
[0120] Furthermore, according to another aspect of the above-described operating mode F3, the control unit 10 is configured to adjust the power supply 9 to apply various predetermined (positive) voltages to the second conductor 5 until a predetermined voltage value for the second conductor 5 is reached, preferably below 1000V, or even more preferably below 900V.
[0121] Preferably, the control unit 10 is configured to regulate the power supply 9 to apply various predetermined (positive) voltages to the second conductor 5 in steps, preferably with each step ranging from 5V to 50V.
[0122] Please note, more specifically, according to control mode F3, control unit 10 is configured to compare the detected electrical parameters related to ionization current IC and the detected electrical parameters related to emission current EC to check whether ionization current IC and / or emission current EC are below a predetermined threshold; if (condition F3A) ionization current IC and / or emission current EC are below the predetermined threshold, then the status parameter representing the operating efficiency of the combination of first conductor 6 and second conductor 5 is set to a value representing the optimal operating efficiency of the combination of first conductor 6 and second conductor 5; otherwise, the status parameter representing the operating efficiency of the combination of first conductor 6 and second conductor 5 is set to a value indicating a technical problem caused by this operating mode F3 (condition F3B).
[0123] Please note that the technical issues corresponding to condition F3B may be related to the insulation of housing 14 or the pressure inside vacuum chamber 13.
[0124] The following section describes an additional control mode, F4, which can be implemented on control unit 10.
[0125] According to this further control mode (denoted as F4), the sensing unit 11 includes a third sensor 18, which is configured to detect electrical parameters consisting of at least one voltage or current selected from the filament 4; furthermore, the control unit 10 is configured to: Adjust the power supply 9 to apply a predetermined relative voltage or current to the filament 4, the first conductor 6, or the second conductor 5; The following components are cross-compared: filament 4, first conductor 6, second conductor 5, and housing 14 surrounding vacuum chamber 13. A short circuit is checked between these cross-compared components by comparing one or more electrical parameters detected from first sensor 7, second sensor 8, or third sensor 18, and one or more voltage or current values applied to these cross-compared components by power supply 9.
[0126] In other words, the F4 control mode includes configuring the control unit 10 to perform multiple pairwise cross-checks between the filament 4, the first conductor 6, the second conductor 5, and the housing 14. The purpose of these cross-checks is to determine whether there is a short circuit between these component pairs.
[0127] Please note that if it is necessary to detect a short circuit between the second conductor 5 and the housing 14, a sensor involving the second conductor 5 will be used, and the power supply 9 will apply a predetermined current or voltage to the second conductor 5.
[0128] The purpose of this control mode F4 is to detect any technical faults or anomalies that may affect the operation of the main electrical components of the irradiation beam emitting device 2 (i.e., filament 4, first conductor 6, second conductor 5, and housing 14). Examples of such faults or anomalies include, but are not limited to, a broken filament 4 that may be in contact with the first conductor 6 or the second conductor 5, or other problems between the second conductor 5 and the first conductor 6. The aim is to identify and resolve any potential problems that may arise between these critical components to ensure the proper operation of the irradiation beam emitting device 2.
[0129] The additional control mode, labeled F5 in Figure 6, will be described below. Advantageously, the control unit 10 can also be configured to implement this specific additional control mode F5.
[0130] According to this additional control mode F5, the sensing unit 11 includes a third sensor 18, which is configured to detect electrical parameters in a group consisting of voltage or current selected from the filament 4.
[0131] Preferably, the third sensor 18 is configured to detect the voltage applied to the filament 4.
[0132] According to this additional control mode F5, the control unit 10 is configured as follows: Adjust the power supply 9 to apply a predetermined value of a selected voltage or current electrical parameter to the filament 4. The selected electrical parameter is different from the electrical parameter detected by the third sensor 18. Based on the electrical parameters detected by the third sensor 18 and the predetermined values of the selected voltage or current parameters applied to the filament 4, it is checked whether the connection of the filament 4 is broken.
[0133] It is worth noting that, according to this control mode F5, if the third sensor 18 is configured to detect the voltage across the filament 4, the control unit 10 is configured to adjust the power supply 9 to apply a predetermined current value to the filament 4. On the other hand, if the third sensor 18 is configured to detect the current flowing through the filament 4, the control unit 10 is configured to adjust the power supply 9 to apply a predetermined voltage value to the filament 4.
[0134] Please note that, according to this control mode F5, the control unit 10 is configured to determine the resistance value of the filament 4 by comparing the voltage applied to the filament 4 and the current flowing through the filament 4, in order to check whether the filament 4 is broken.
[0135] Essentially, the comparison result performed by the control unit 10 according to this additional control mode F5 is a status parameter indicating whether the filament 4 is intact or damaged. Therefore, the main purpose of control mode F5 is to verify whether the filament 4 is broken (presence (condition F5B in Figure 6)) or not broken (absence (condition F5A in Figure 6)).
[0136] It should be noted that, regardless of the mode shown in Figure 6, the control unit 10 can be configured to implement one or more of the control modes F2, F3, F4 and F5 described above, in addition to the main control mode F1, even if their time series are different from the time series shown in Figure 6.
[0137] In a specific implementation, the control unit 10 is configured to execute control modes in the sequence shown in Figure 6.
[0138] Please note that if the control unit 10 is configured to execute multiple different control modes (F1, F2, F3, F4, F5), the control unit 10 is configured to switch between control modes and another control mode according to a predetermined operating setting of the same control unit 10.
[0139] It is worth noting, particularly referring to Figure 6, that all conditions marked with the suffix "B" (F2B, F3B, F4B, F5B) represent termination conditions in the control program shown in Figure 6, which is implemented by the control unit 10. Under these termination conditions, the control unit 10 determines a status parameter whose value indicates a malfunction or poor performance of the irradiation beam emitting device 2.
[0140] The control device 1 also includes a connector 19 configured to couple with a corresponding irradiation beam connector 17 disposed in the housing 14 of the irradiation beam emitting device 2.
[0141] Connector 19 includes a plurality of connecting wires (19A, 19B, 19C, 19D) configured to couple with corresponding wires (17A, 17B, 17C, 17D) of the irradiation beam connector 17 of the housing 14 of the irradiation beam emitting device 2.
[0142] Please note that the electrical wires (17A, 17B, 17C, 17D) of the irradiation beam connector 17 are connected to the filament 4, the first conductor 6, and the second conductor 5, respectively.
[0143] Also note that one of these electrical conductors (17A, 17B, 17C, 17D), indicated by reference numeral 17A in Figure 5, can be used as a common ground (i.e., zero voltage) between filament 4, first conductor 6, and second conductor 5.
[0144] Connector 19 can be easily and quickly attached to / detached from the corresponding irradiation beam connector 17.
[0145] Typically, when using the irradiation beam emitting device 2 to sterilize materials (e.g., packaging material rolls), the irradiation beam connector 17 is connected to a control connector (not shown) that provides the appropriate voltage or current to enable the irradiation beam emitting device 2 to operate in sterilization mode, thereby emitting an electron beam thereon.
[0146] By disconnecting the control connector from the irradiation beam connector 17 and replacing it with the connector 19 of the control device 1, maintenance technicians can monitor the status of the irradiation beam emitting device 2.
[0147] The control device 1 according to the present invention has many advantages.
[0148] First, control device 1 greatly simplifies the maintenance and periodic monitoring procedures of the irradiation beam emitting device 2. It eliminates the need to remove the irradiation beam emitting device 2 from its installation location to assess its operational efficiency. Instead, control device 1 can be quickly and easily connected to the irradiation beam emitting device 2 in the field, thereby rapidly determining its status parameters.
[0149] This significantly reduces the downtime of the irradiation beam emitting device 2.
[0150] Furthermore, control device 1 facilitates the implementation of one or more auxiliary and automated control procedures, enabling even technicians with limited technical skills to assess the operational efficiency of the irradiation beam emitting device 2. This simplification of the maintenance process offers significant advantages.
[0151] Furthermore, the control device 1 can employ different control modes (F1, F2, F3, F4, F5), each designed to detect specific technical faults, thus demonstrating excellent effectiveness in identifying a variety of faults.
[0152] In addition, control device 1 helps the irradiation beam emitting device 2 to operate optimally because it performs a series of checks to ensure the complete operational efficiency, effectiveness and sterilization capability of the irradiation beam emitting device 2.
[0153] According to the present invention, a sterilization system 100 for sterilizing packaging material PM is also disclosed, comprising: A sterilization apparatus 3 for sterilizing (packaging) material PM, the apparatus having an irradiation beam emitting device 2, the irradiation beam emitting device 2 including a vacuum chamber 13, a filament 4, a second conductor 5 and a first conductor 6 configured to emit electrons by the thermionic effect when heated, the filament 4, the second conductor 5 and the first conductor 6 being located inside the vacuum chamber 13. Control device 1, which is used to control the state of the irradiation beam emitting device 2 according to any of the appended claims.
[0154] According to the present invention, a method for controlling the operating efficiency of the irradiation beam emitting device 2 is also disclosed.
[0155] This method can be applied to the irradiation beam emitting device 2 of the sterilization apparatus 3 for sterilizing (preferably packaging) material PM.
[0156] As described above, the irradiation beam emitting device 2 includes a filament 4, a first conductor 6, and a second conductor 5 configured to emit electrons via the thermionic effect when heated.
[0157] The filament 4, the first conductor 6, and the second conductor 5 are located inside the vacuum chamber 13, where the gas is under vacuum conditions.
[0158] According to the present invention, the method includes the following steps (phases) that define the main control mode F1 of the state of the irradiation beam emitting device 2: Adjust the power supply 9 to simultaneously apply a predetermined current to the filament 4 to emit electrons, apply a predetermined (preferably positive) voltage to the second conductor 5, and apply a predetermined (preferably negative) voltage to the first conductor 6; Detect electrical parameters related to the current flowing through the first conductor 6, which is defined as the ionization current IC, and detect electrical parameters related to the current flowing through the second conductor 5, which is defined as the emission current EC; Based on the detected electrical parameters related to the ionization current IC and the detected electrical parameters related to the emission current EC, at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 is derived.
[0159] According to another aspect of the method, the step of adjusting the power supply 9 to simultaneously apply a predetermined current to the filament 4 to emit electrons, apply a predetermined voltage to the second conductor 5, and apply a predetermined voltage to the first conductor 6 includes the following steps: adjusting the power supply 9 to apply multiple predetermined different current values to the filament 4 at different time points, thereby generating multiple different electron emissions, and wherein the step of deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 includes the following steps: deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 based on detected electrical parameters related to the ionization current IC and detected electrical parameters related to the emission current EC obtained at different filament 4 current values.
[0160] According to another aspect, the step of deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 includes the following steps: deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 at a predetermined high emission current EC value (preferably contained between 10mA and 30mA).
[0161] According to another aspect, the step of deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 includes the following steps: deriving at least one state parameter representing the operating efficiency of the irradiation beam emitting device 2 based on the ionization current IC, the emission current EC and at least one reference parameter.
[0162] Preferably, the at least one reference parameter defines the relationship between the ionization current IC and the emission current EC relative to the vacuum pressure inside the vacuum chamber 13 of the irradiation beam emitting device 2.
[0163] In other words, the at least one reference parameter includes at least one value (e.g., the ratio of ionization current IC to emission current EC) that defines a mathematical linear relationship between the ionization current IC and the emission current EC relative to different vacuum pressures inside the vacuum chamber 13 of the irradiation beam emitting device 2.
[0164] The setup procedure for the control device 1 will now be briefly described, which enables the method of the present invention to be effectively executed on a specific irradiation beam emitting device 2.
[0165] According to the setup procedure, an initial setup step is provided for the at least one reference parameter, which includes the following steps: providing multiple identical test irradiation beam emitting devices 2, each device having a vacuum chamber 13 with different internal vacuum pressure values. A single irradiation device can be used and its internal vacuum pressure value adjusted, or multiple emitting devices 2 exhibiting different internal vacuum pressure values can be used.
[0166] According to this aspect, the method further includes the following steps, which are performed for at least one vacuum pressure value and / or for each test irradiation beam emitting device 2: Adjust the power supply 9, for example, by simultaneously applying a predetermined current to the filament 4 to emit electrons, applying a predetermined voltage to the first conductor 6, and applying a predetermined voltage to the second conductor 5; Detect at least one electrical parameter related to the current flowing through the first conductor 6, which is defined as the ionization current IC, and detect at least one electrical parameter related to the current flowing through the second conductor 5, which is defined as the emission current EC; The at least one reference parameter is derived from the detected parameters related to the ionization current IC and the detected parameters related to the emission current EC; The at least one reference parameter is stored, preferably, the parameter being associated with an internal vacuum pressure value.
[0167] It is important to note that by knowing the vacuum pressure value inside the vacuum chamber 13 of each test irradiation beam emitting device 2 in advance, a correlation between the vacuum pressure and the ionization current IC and emission current EC values detected at a predetermined filament current FC can be established using at least one reference parameter.
[0168] Essentially, this allows for the derivation of at least one reference parameter that can be used to model the curves C1, C2, C3, and C4 shown in Figure 7, which correspond to different vacuum pressures represented by the test irradiation beam emitting device 2.
[0169] It is worth mentioning that this setup procedure needs to be repeated when using different irradiation beam emitting devices 2 with different sizes and characteristics.
[0170] Essentially, the setup or calibration steps can only obtain reliable reference parameters applicable to monitoring the same irradiation beam emitting device 2 as the device under test.
[0171] According to another aspect, corresponding to the previously disclosed control mode F2 configuration with reference to FIG6. The method includes the following steps: Detect electrical parameters related to the voltage applied to filament 4; Adjust the power supply 9 to apply multiple different predetermined currents to the filament 4, these currents being defined as filament current FC; Based on the detected electrical parameters related to the voltage applied to the filament 4 and the filament current FC, the state parameters of the filament 4 are derived, which represent the operating efficiency of the filament 4 of the irradiation beam emitting device 2.
[0172] According to another aspect, the step of deriving the state parameters of the filament 4 includes the following steps: based on the derived state parameters of the filament 4, deriving the vacuum pressure indication inside the vacuum chamber 13 of the irradiation beam emitting device 2.
[0173] According to another aspect, corresponding to the previously disclosed content regarding the control mode F3 configuration with reference to FIG6, the method further includes the following steps: Adjust the power supply 9 to apply a predetermined voltage to the first conductor 6; Adjust the power supply 9 to apply multiple different predetermined voltages to the second conductor 5; Based on the detected electrical parameters related to the ionization current IC and the detected electrical parameters related to the emission current EC, the state parameters of the first conductor 6 and the second conductor 5 are derived, which represent the operating efficiency of the combination of the first conductor 6 and the second conductor 5.
[0174] According to another aspect, corresponding to the previously disclosed content regarding the control mode F4 configuration with reference to FIG6, the method further includes the following steps: Detect the electrical parameters in the group consisting of the voltage or current of the selected filament 4; Adjust the power supply 9 to apply a predetermined relative voltage or current to the filament 4, the second conductor 5, or the first conductor 6; Cross-comparison is performed on at least one pair of cross-comparison elements: filament 4, first conductor 6, second conductor 5, and housing 14 surrounding vacuum chamber 13, to check for a short circuit between the pair of cross-comparison elements based on one or more detected electrical parameters and one or more voltages or currents applied to the cross-comparison elements by power supply 9.
[0175] According to another aspect, corresponding to the previously disclosed content regarding the control mode F5 configuration with reference to FIG6, the method further includes the following steps: Detect the electrical parameters in the group consisting of the voltage or current of the selected filament 4; Adjust the power supply 9 to apply a predetermined value of a selected voltage or current parameter to the filament 4. The selected electrical parameter is different from the electrical parameter in the group of voltages or currents selected from the filament 4 detected in the previous step. Based on the detected electrical parameters and the predetermined values of the selected voltage or current electrical parameters applied to the filament 4, check whether there is a break in the filament 4.
[0176] It is worth noting that the method of the present invention provides the same advantages as the control device 1 previously described with respect to the present invention.
[0177] In other words, this method allows for particularly rapid and accurate diagnosis and precise control of the irradiation beam emitting device 2.
[0178] According to the present invention, a use of a control device 1 is also disclosed, wherein the control device 1 according to any of the appended claims is used to control the operating efficiency of an irradiation beam emitting device 2 of a sterilization apparatus 3 for sterilizing (preferably packaging) material PM, wherein the irradiation beam emitting device 2 includes: a filament 4, a second conductor 5, and a first conductor 6 configured to emit electrons by thermionic emission effect when heated, all of which are located inside a vacuum chamber 13.
[0179] According to one aspect, the sensing unit 11 may include a third sensor 18 configured to detect parameters of the voltage or current of the indicator filament 4, and wherein the control unit 10 is further configured to: Adjust the power supply 9 to apply a predetermined value of a selected voltage or current parameter to the filament 4. The selected parameter is different from the parameter detected by the third sensor 18. Based on the parameter detected by the third sensor 18 and the predetermined value of the voltage or current parameter applied to the filament 4, check whether the connection of the filament 4 is broken.
[0180] According to one aspect, the sensing unit 11 may include a third sensor 18 configured to detect electrical parameters in a group consisting of voltages or currents selected from the filament 4, and wherein the control unit 10 is further configured to: Adjust the power supply 9 to apply a predetermined relative voltage or current to the filament 4, the second conductor 5, or the first conductor 6; The following components are cross-compared: filament 4, first conductor 6, second conductor 5, and housing 14 surrounding vacuum chamber 13, to check for short circuits between any of the compared components. The cross-comparison is based on one or more electrical parameters detected by first sensor 7, second sensor 8, or third sensor 18, and one or more voltage or current values applied by power supply 9 to the cross-compared components.
[0181] The known irradiation beam emitting device 2 includes a cathode, an exit window, a grid, an anode, and a filament 4. During normal operation, the filament 4 emits electrons, which are accelerated toward the exit window by the electromagnetic field generated by the voltage applied to the cathode and grid. The first conductor 6 can be the cathode. The second conductor 5 can be the grid of the irradiation beam emitting device 2.
[0182] The control device 1 can be directly connected to the irradiation beam emitting device 2 used for sterilization. In particular, the control device 1 includes a power supply 9, which can be directly connected to the filament 4, the first conductor 6 and the second conductor 5 of the irradiation beam emitting device 2 to supply power to them.
[0183] In other words, the irradiation beam emitting device 2 includes a power port. This power port is connected to the filament 4, the first conductor 6, and the second conductor 5, such as a grid and / or a cathode. During normal operation, a generator is connected to the power port to supply power to the emitting device 2, enabling it to emit an irradiation beam for sterilization.
[0184] The power port can be directly connected to the power supply 9 of the control device 1. In this way, the control device 1 can directly control the operating efficiency of the irradiation beam emitting device 2.
[0185] Advantageously, the operational efficiency of the launch device itself can be evaluated using its components, without the need for external components or sensors, such as ion gauges.
Claims
1. A control device (1) for an irradiation beam launching device (2), wherein The irradiation beam emitting device (2) is configured to emit an irradiation beam for sterilizing an object and comprises a vacuum chamber (13), a filament (4) configured to emit electrons by thermionic effect when heated, a first electric conductor (6) and a second electric conductor (5), said filament (4), first conductor (6) and second conductor (5) being all arranged inside said vacuum chamber (13), The control device (1) comprises: a power supply (9) connectable to said filament (4), said first conductor (6) and said second conductor (5) of said irradiation beam emitting device (2) to power them; a sensing unit (11) comprising at least one first sensor (7) configured to detect at least one electrical parameter related to a current flowing through said first conductor (6), defined as ionization current (IC), and a second sensor (8) configured to detect at least one electrical parameter related to a current flowing through said second conductor (5), defined as emission current (EC); a control unit (10) coupled to said power supply (9) and to said sensing unit (11) to receive therefrom the detected electrical parameters and further configured for executing a status master control mode (Fl) of said irradiation beam emitting device (2), which mode comprises: adjusting said power supply (9) to impose a predetermined current on said filament (4) to emit electrons; adjusting said power supply (9) to impose a predetermined voltage on said first conductor (6); adjusting said power supply (9) to impose a predetermined voltage on said second conductor (5); and deriving at least one status parameter representative of the operating efficiency of said irradiation beam emitting device (2) from said detected electrical parameters related to said ionization current (IC) and said detected electrical parameters related to said emission current (EC).
2. The control device (1) according to claim 1, wherein one of said predetermined voltage on said first conductor (6) and said predetermined voltage on said second conductor (5) is positive, while the other between said predetermined voltage on said second conductor (5) and said predetermined voltage on said first conductor (6) is negative.
3. The control device (1) according to claim 1 or 2, wherein said control unit (10) is configured for: adjusting said power supply (9) to impose a plurality of predetermined different filament (4) current values to said filament (4) at different points in time, thereby generating a plurality of different electron emissions; deriving said status parameter from the detected electrical parameters related to said ionization current (IC) and the detected electrical parameters related to said emission current (EC) at different filament (4) current values.
4. Control device (1) according to any one of the preceding claims, comprising a memory (12) connected to or integrated in said control unit (10) for storing at least one reference parameter, and wherein said control unit (10) is configured to derive said at least one status parameter representative of the operating efficiency of said radiation beam emitting device (2) as a function of said detected electrical parameters related to said ionization current (IC) and said emission current (EC) and said at least one reference parameter stored in said memory (12).
5. Control device (1) according to the preceding claim, wherein said at least one reference parameter defines a relationship between said ionization current (IC) and said emission current (EC), preferably said relationship is with respect to the vacuum pressure inside said vacuum chamber (13) of said radiation beam emitting device (2).
6. Control device (1) according to the preceding claim, wherein said at least one reference parameter comprises at least one value defining a mathematical linear relationship between said ionization current (IC) and said emission current (EC) with respect to different vacuum pressures inside said vacuum chamber (13) of said radiation beam emitting device (2).
7. Control device (1) according to any one of the preceding claims, wherein said sensing unit (11) comprises a third sensor (18) configured to detect an electrical parameter related to the voltage across said filament (4), and wherein said control unit (10) is further configured for: adjusting said power supply (9) so as to apply a plurality of different predetermined currents to said filament (4), defined as filament currents (FC); deriving at least one status parameter of said filament (4) representative of the operating efficiency of said filament (4) of said radiation beam emitting device (2) as a function of said detected electrical parameter related to said voltage across said filament (4) and said filament currents (FC) applied by said power supply (9).
8. Control device (1) according to the preceding claim, wherein said control unit (10) is further configured to derive an indication of the vacuum pressure inside said vacuum chamber (13) of said radiation beam emitting device (2) based on the derived status parameter of said filament (4).
9. Control device (1) according to any one of the preceding claims, wherein said control unit (10) is further configured for: adjusting said power supply (9) so as to apply a predetermined voltage across said first conductor (6); adjusting said power supply (9) so as to apply a plurality of different predetermined voltages across said second conductor (5); deriving at least one first conductor (6)-second conductor (5) status parameter representative of the operating efficiency of the combination of said first conductor (6) and said second conductor (5) based on said detected electrical parameter related to said ionization current (IC) and said detected electrical parameter related to emission current (EC).
10. Control device (1) according to any one of the preceding claims, wherein said radiation beam emitting device (2) comprises a cathode and a gate, wherein said first conductor (6) comprises said cathode and / or said second conductor (5) comprises said gate of said radiation beam emitting device (2).
11. Control device (1) according to any one of the preceding claims, wherein The irradiation beam emitting device (2) comprises a power supply port, and wherein the power supply (9) of the control device (1) is connectable to the power supply port of the irradiation beam emitting device (2).
12. A sterilization system (100) comprising: a sterilization apparatus (3) having at least one irradiation beam emitting device (2) comprising a vacuum chamber (13), a filament (4) configured to emit electrons by thermionic effect upon heating, a first conductor (6) and a second conductor (5), said filament (4), first conductor (6) and second conductor (5) being all located inside the vacuum chamber (13); a control device (1) for controlling the state of the irradiation beam emitting device (2) according to any of the preceding claims.
13. A method of controlling the operating efficiency of an irradiation beam emitting device (2), wherein the irradiation beam emitting device (2) comprises a vacuum chamber (13), a filament (4) configured to emit electrons by thermionic effect upon heating, a first conductor (6) and a second conductor (5), said filament (4), first conductor (6) and second conductor (5) being all located inside the vacuum chamber (13), the method comprising: adjusting a power supply (9) to apply a predetermined voltage on the filament (4) to emit electrons, to apply a predetermined voltage on the first conductor (6) and to apply a predetermined voltage on the second conductor (5) to define an electric field between the second conductor (5) and the first conductor (6); detecting an electrical parameter related to the current flowing through the first conductor (6), defined as ionization current (IC), and detecting an electrical parameter related to the current flowing through the second conductor (5), defined as emission current (EC); deriving at least one state parameter representative of the operating efficiency of the irradiation beam emitting device (2) from the detected electrical parameter related to the ionization current (IC) and the detected electrical parameter related to the emission current (EC).
14. The method of the preceding claim, wherein, The step of adjusting the power supply (9) comprises the step of adjusting the power supply (9) to apply a plurality of predetermined different current values on the filament (4) to produce a plurality of different electron emissions at different points in time, and wherein the step of deriving at least one state parameter representative of the operating efficiency of the irradiation beam emitting device (2) comprises the step of deriving at least one state parameter representative of the operating efficiency of the irradiation beam emitting device (2) from the detected electrical parameter related to the ionization current (IC) and the detected electrical parameter related to the emission current (EC) at the different filament (4) current values.
15. The method according to the preceding claim, wherein, The step of deriving at least one state parameter representative of the operating efficiency of the irradiation beam emitting device (2) comprises the step of deriving at least one state parameter representative of the operating efficiency of the irradiation beam emitting device (2) from the detected electrical parameter related to the ionization current (IC), the emission current (EC) and at least one reference parameter; wherein said method further comprises an initial setting step for calculating said at least one reference parameter, which step comprises: providing at least one test irradiation beam emitting device (2) having a vacuum chamber (13) with an internal vacuum pressure value, said method further comprising the following steps, which steps are performed for at least one internal vacuum pressure value: adjusting said power supply (9) to apply a predetermined current on said filament (4) to emit electrons, a predetermined voltage on said first conductor (6) and a predetermined voltage on said second conductor (5); detecting at least one electrical parameter related to the current flowing through said first conductor (6), defined as ionization current (IC), and detecting at least one electrical parameter related to the current flowing through said second conductor (5), defined as said emission current (EC); calculating said at least one reference parameter as a function of the detected electrical parameter related to ionization current (IC) and the detected electrical parameter related to emission current (EC); storing said at least one reference parameter, preferably together with said internal vacuum pressure value.