Air purification system for an ion mobility spectrometer, method of operating the same, and ion mobility spectrometer

Abstract

A method of operating an air purification system (24'') for an ion mobility spectrometer, the method comprising: operating the ion mobility spectrometer in a first sampling mode, which includes circulating an air flow through a closed air circulation system including a drift chamber (12) of the ion mobility spectrometer and a first sieve (70) of the air purification system; and operating the ion mobility spectrometer in a first regeneration mode, which includes heating the first sieve and circulating the first air flow through a second sieve (72) of the air purification system and the drift chamber (12), while passing a second air flow through the first sieve (70) to an outlet (76).

Description

Technical Field

[0001] The present invention relates to a method and an apparatus, and more particularly to an air purification system that can be used in a trace detection device such as an ion mobility spectrometer.

Background Art

[0002] In an ion mobility spectrometer or other system for sampling vapors, it may be effective to supply purified and dried air. For this purpose, typically, molecular sieves contained in a so-called sieve pack are often used. Usually, the molecular sieve is provided by filling a large number of spheres made of a zeolite material with a diameter of about 2 mm into an external housing connected to a gas flow path passing through the detector. Spheres with different diameters may be used, and materials other than zeolite may be used. The gas flowing through the detector is circulated while passing through the sieve and then recirculated within the detector. While passing through the pack, the gas flows while meandering outside the spheres, and a part of it passes through the inside of the spheres. These packs (sometimes called towers) may be composed of a solid block of zeolite held in a close-fitting housing. Such a block may have a large number of flow paths through which the gas can pass. Various configurations can be used for such sieves.

[0003] Over time, the effectiveness of the sieve may decrease. For example, moisture may accumulate, and the ability to take in moisture from the air passing through the sieve may decrease. Excessive moisture contained in the drift gas of an ion mobility spectrometer is known to be a problem.

[0004] To solve this problem, the sieve pack can be regenerated by heating while flowing gas through the sieve pack. In such a method, typically, it is necessary to remove the sieve from the detector and replace it or stop using the detector.

[0005] In a "total loss" air purification system, the dry air flowing through the chemical detection system is continuously fed in from the external ambient air and purified and dried using a molecular sieve before being used in the detector. Since the air exiting the detector is sent out (is "lost") into the atmosphere, this air flow is a "total loss". This is in contrast to a "closed loop" approach, where in normal operation, the dry air flow is sent in a continuous loop and the air is dried using a molecular sieve within the loop, i.e., there is (intentionally) no air in or out.

[0006] In such systems, additional configurations for sieve regeneration are generally required. Since these configurations can be bulky or heavy, they can be a problem in portable detectors.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Aspects and embodiments of the present disclosure are set forth in the claims and are aimed at solving at least some of the above-described technical problems and other problems.

Means for Solving the Problems

[0008] One aspect of the present disclosure provides a method of operating an air purification system of an ion mobility spectrometer that can simultaneously perform bake-out of a drift tube and a detector inlet while regenerating a molecular sieve. One such method is described in claim 1 and includes selectively operating the ion mobility spectrometer in either a sampling mode or a regeneration mode, although in some embodiments, sampling and regeneration may be performed simultaneously.

[0009] Examples of the method specified in claim 1 may include switching an ion mobility spectrometer to a second playback mode, which passes a second air flow through a second sieve and sends it to an exhaust port, for example, while discharging from the ion mobility spectrometer, heating the second sieve, and circulating the first air flow through a first sieve and a drift chamber of an air purification system. Such a method may also include switching the ion mobility spectrometer to a second sampling mode that uses the second sieve instead of the first sieve in a closed air circulation system. The switching between modes may include starting the operation in another mode after stopping the operation in a certain mode.

[0010] Another operating method of the air purification system of an ion mobility spectrometer is also disclosed, which simultaneously performs a bake-out of a drift tube and a detector inlet while regenerating the sieve. One such method is Pass the second air flow through the first sieve and send it to the exhaust port, for example, while discharging from an ion mobility spectrometer, heat the first sieve, and circulate the first air flow through the second sieve and the drift chamber of the air purification system. Operating the ion mobility spectrometer in a first regeneration mode including; and switching the ion mobility spectrometer to a second regeneration mode, wherein the second regeneration mode passes the second air flow through the second sieve and sends it to the exhaust port, for example, while discharging from an ion mobility spectrometer, heats the second sieve, and circulates the first air flow through the first sieve and the drift chamber of the air purification system. The method may also include operating the air purification system in one of two possible sampling modes and selectively switching between the two sampling modes. The first sampling mode may include circulating the air flow in a closed air circulation system including the drift chamber of the ion mobility spectrometer and the first sieve of the air purification system. In the second sampling mode, the second sieve may be switched to connect to the drift chamber so that the second sieve is used in place of the first sieve in the closed air circulation system. The first sampling mode can be operated simultaneously with the second regeneration mode, and the second sampling mode can also be operated simultaneously with the first regeneration mode.

[0011] In addition to such simultaneous operation, in the context of the present disclosure, it will be understood that this aspect of the present disclosure and other aspects can be operated to provide the following operations. (1) Operation in one of the first regeneration mode and the second regeneration mode corresponding to the operation in the first sampling mode or the second sampling mode. (2) Operation in the second regeneration mode following the operation in the first sampling mode, and operation in the first regeneration mode following the operation in the second sampling mode.

[0012] The method described herein may include switching modes in a sequence such as a cycle where the sieve used for sampling is a sieve heated in a preceding operating mode. For example, this cycle may include switching modes in an order such as a first sampling mode, a second regeneration mode, a second sampling mode, a first regeneration mode, a first sampling mode, and so on.

[0013] In the first regeneration mode, a second air flow may be supplied from a second sieve. In the first regeneration mode, an ambient air flow may be mixed with the air taken out from the ion mobility spectrometer. In the first regeneration mode, a second air flow may be supplied by a part of the first air flow. A part of the first air flow may be diverted from the first air flow using a flow orifice. Diverting the first air flow may include operating an exhaust valve to enable the second air flow to go towards the outlet.

[0014] One aspect provides an air purification system for an ion mobility spectrometer, the system comprising an inlet and an outlet configured to connect the air purification system to a drift chamber of the ion mobility spectrometer to form a closed air circulation system, an outlet for discharging air from the system, for example from the ion mobility spectrometer, a first sieve, and a second sieve, wherein the air purification system is configured to provide a first sampling mode in which air circulates in the closed air circulation system and the first sieve is connected to form part of the closed air circulation system. The air purification system may be configured to be switched from the sampling mode to any of the following. (a) A first regeneration mode in which the first sieve is heated while a second air flow passes through the first sieve and is discharged from the ion mobility spectrometer to the outlet, and a first air flow circulates through the second sieve and the drift chamber (b) In the second regeneration mode, while the second air flow passes through the second sieve and is discharged from the ion mobility spectrometer to the outlet, the second sieve is heated, and the first air flow passes through the first sieve and the drift chamber and circulates.

[0015] In the first regeneration mode, the second air flow may be supplied from the second sieve. In the first regeneration mode, the ambient air flow may be mixed with the air taken in through the inlet from the ion mobility spectrometer. In the first regeneration mode, the second air flow may be supplied by a part of the first air flow.

[0016] The air purification system may further be configured to provide a second sampling mode in a closed air circulation system, in which the second sieve is used instead of the first sieve. The second sampling mode and the first regeneration mode may operate simultaneously. In these embodiments and other embodiments, the system downtime required for sieve regeneration can be reduced.

[0017] The second sampling mode and the first regeneration mode may be operated simultaneously. The simultaneous operation of these two modes may be configured by using the first air flow to supply the drift gas required for the operation of the ion mobility spectrometer for analyzing the sample while heating the first sieve to regenerate the first sieve. Thus, the second sieve can be used for the sampling operation of the IMS while the first sieve is being regenerated.

[0018] A flow controller such as a flow orifice may be configured to divert a part of the first flow to supply the second flow. This system may include a discharge valve that can be opened to allow the second air flow to go towards the outlet and can be closed to block the air flow to the outlet.

[0019] The air purification system may further be configured such that while a second air flow passes through the second sieve and is discharged from the ion mobility spectrometer to the discharge port, the second sieve is heated and the first air flow is switched to a second regeneration mode in which it circulates through the first sieve and the drift chamber.

[0020] The air purification system may be configured to switch modes in a sequence having a cycle such that the sieve used for sampling is the sieve heated in the preceding operating mode. For example, this cycle may include switching modes in an order such as a first sampling mode, a second regeneration mode, a second sampling mode, a first regeneration mode, a first sampling mode, and so on.

[0021] One aspect also provides an ion mobility spectrometer including an air purification system such as to exemplify all the configurations described in this specification and / or the claims. One such ion mobility spectrometer includes an inlet and an outlet, the inlet and the outlet being selectively connectable to a first sieve and a second sieve, an air purification system, a drift chamber connected to the outlet and the inlet of the air purification system, the purified and dried air from the outlet of the air purification system being supplyable through the drift chamber, a discharge port connected to the air purification system for discharging air from the ion mobility spectrometer, and a heater, the air purification system being configured to regenerate the first sieve by heating the first sieve and changing the flow of the air dried by the second sieve passing through the first sieve and heading towards the discharge port.

[0022] As an alternative, during the regeneration of the first sieve, the air dried by the second sieve is also circulated from the outlet of the air purification system through the drift chamber to the inlet of the air purification system. Also, the air purification system may be configured to regenerate the second sieve by heating the second sieve, changing the flow of the air dried by the first sieve to pass through the second sieve and directing it towards the outlet.

[0023] During the regeneration of the second sieve, the air dried by the first sieve is also circulated from the outlet of the air purification system through the drift chamber to the inlet of the air purification system.

[0024] In one embodiment of the present disclosure, for example, a semi-permeable material (such as Nafion) can be eliminated, and additional pumps and other hardware can also be eliminated, thus reducing weight and volume. These advantages can be achieved using an inexpensive one-way "check" valve and perhaps some additional inexpensive filters.

[0025] In one embodiment, during sampling, the gas flow passes through only one of the two sieves, while the "other tower" is not used (or may be in the process of regeneration). In one embodiment, in the regeneration mode, a portion of the flow exiting one sieve is directed (e.g., in the reverse direction) to flow through the other sieve, and the other sieve is heated and thus regenerated. The moist air exiting the regeneration tower is discharged from the unit to the ambient atmosphere.

[0026] To compensate for the loss of air from the regeneration tower, an air intake (e.g., a fixed impedance) may be opened upstream of the sieve to take in air (in the case of Figure 2, there is an intake at the inlet of the pump).

[0027] In some embodiments, such as those described with reference to FIG. 2, during regeneration, there remains a stream of purified dry air available for the detector. This stream of dry air may be used to bake out the detector (e.g., sampling channels and / or inlets and / or drift tube 12) simultaneously with the regeneration of the sieve. It may also be possible to enable sampling by the detector during regeneration.

[0028] As would be understood by one of ordinary skill in the art in the context of the present disclosure, other embodiments are also contemplated.

Brief Description of the Drawings

[0029] Next, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Figure 1

Mode for Carrying Out the Invention

[0030] FIG. 1 shows an ion mobility spectrometer system including a detector inlet 10 and a drift tube 12. The detector inlet 10 is connected to the drift tube by sampling means that provide a bulk flow restriction (e.g., a membrane or pinhole) or sampling means that provide a direct connection such as a tube. A flow path is provided for a stream of air that carries the sample and introduces it to the detector inlet, for example, a stream that can carry the sample from a desorber to the sampling means and then introduce it to the drift tube 12 there.

[0031] The drift tube 12 may include a reaction region 12-1. This reaction region is connected to the detector inlet by a flow path and is separated from the drift region 12-3 by a gate 12-2. At the end of the drift region 12-3 located away from the gate 12-2, a detector 12-4 such as a Faraday cup may be provided for performing ion mobility spectrometry to identify the target substance in the sample introduced into the ion mobility spectrometer through the detector inlet 10.

[0032] When used for sample analysis, it will be understood that the drift gas generally flows from the detector 12-4 along the drift region 12-3 towards the gate. Therefore, the drift gas inlet 18 is provided at the same end of the drift region 12-3 as the detector, and the drift gas outlet 20 is provided at the end of the drift region 12-3 near the gate 12-2, for example, near the sample inlet, and is arranged, for example, between the sample inlet and the gate.

[0033] Also, a vapor doping system 22 may be connected to the drift tube 12 to supply a certain amount of substances such as calibration substances and dopants to the drift tube 12.

[0034] The ion mobility spectrometer shown in FIG. 1 includes an air purification system 24'' for purifying and drying air, such as a drift gas, that circulates inside the ion mobility spectrometer. The air purification system 24'' has an inlet 26 for receiving the air to be purified and dried and an outlet 28 for supplying the purified and dried air used in the ion mobility spectrometer.

[0035] To supply an air flow that can be used to supply a certain amount of vapor from the vapor doping system 22 to the drift tube 12, the outlet 28 of the air purification system 24 is connected to the drift gas inlet 18 and the vapor doping system 22.

[0036] The apparatus shown in FIG. 1 includes a heater. A plurality of heaters, for example, one heater for each sieve and other heaters for other components of the detection system, may be provided. For clarity, the heaters are not shown in the drawings, but may be operable to heat at least the sieve and / or the remaining part of the detector to a high temperature such as at least 200 degrees Celsius. The heaters may be configured to heat one of the two sieves more than the other, for example, to heat one sieve to at least 200 degrees Celsius and maintain the other sieve at the normal operating temperature.

[0037] The ion mobility spectrometer shown in FIG. 1 includes a plurality of three-way valves 34, 36, 38, 40. Each of these valves has a first port, a second port, and a third port. The first port can be selectively connected to either the second port or the third port. The three-way valve is configured such that when the first port is connected to the second port (e.g., by being separated from the primary port), the third port is closed so that fluid does not flow into or out of the third port. Similarly, when the first port is connected to the third port, the second port is also closed. When these three-way valves are in the off state, the first port is connected to the second port and the third port is closed. It will be understood that in the context of the present disclosure, other flow control means may be used to provide the flow path changing function of these valves described herein.

[0038] The drift gas outlet 20 of the drift tube 12 is connected by a flow path leading to the inlet 26 of the air purification system 24''.

[0039] The inlet 26 of the air purification system 24'' is connected to the intake port of the first pump 50'. Also, the intake port of this pump 50' is also connected to the first port of the fifth three-way valve 80 (hereinafter referred to as the "intake valve 80"). The third port of the intake valve 80 is connected to the ambient air inlet 48, and the second port is blocked. Therefore, in the off state of this valve 80, the intake port of the first pump is connected only to the inlet 26 of the air purification system 24'', while the ambient air inlet 48 from the ambient air is blocked.

[0040] The exhaust port of the first pump 50' is connected to the safety valve 54, and is also connected to the second port of the sixth three-way valve 82 (hereinafter referred to as the "first sheave valve 82") and the third port of the seventh three-way valve 84 (hereinafter referred to as the "second sheave valve 84"). The third port of the first sheave valve 82 and the second port of the second sheave valve 84 are both connected to the first port of the tenth three-way valve 86 (hereinafter referred to as the "air discharge valve 86"). The third port of the air discharge valve 86 is connected to the evaporator 61 by the dryer reservoir 60, and is connected to the air outlet 76 of the air purification system 24'' for discharging air to the surrounding atmosphere by the evaporator 61. Since the second port of the air discharge valve 86 is closed, when the air discharge valve 86 is off, the outlet of the air purification system 24'' is in a closed state.

[0041] The first port of the first sheave valve 82 is connected to the first port of the first molecular sieve 70. The first port of the second sheave valve is connected to the first port of the second molecular sieve 72. The first molecular sieve 70 has a second port, and this port is connected to the inflow part of the first one-way valve 90, the inflow part of the second one-way valve 92, and the second port of the second molecular sieve 72. Therefore, the second port of the second molecular sieve 72 is also naturally connected to the second port of the first molecular sieve 70 and the inflow parts of the two one-way valves 90, 92. A flow impedance orifice 94 is provided at the connection part between the second port of the first molecular sieve 70 and the second port of the second molecular sieve 72 (therefore, the inflow parts of the two one-way valves are also separated by this orifice 94). The outflow parts of these two one-way valves 90, 92 are both connected to the outflow part of the air purification system 24''.

[0042]

Table 1

[0043] The system shown in Figure 1 has two operating modes, and each mode has two states. · Sampling - State 1 · Sampling - State 2 · Bake - out + Playback State 1 · Bake - out + Playback State 2

[0044] In the sampling operation mode, the air flow is sent through the sampling channel to the inlet of the drift tube 12. In sampling state 1, both of the two sheave valves are off, and the discharge valve is also off. Therefore, in the air purification system, the air flowing into the inlet of the 24’’ air purification system is guided through the first molecular sieve and the first one - way valve to the outlet of the purification system. Conversely, in sampling state 2, since both of the two sheave valves are on, the air flowing into the inlet of the air purification system is guided through the second molecular sieve and the second one - way valve to the outlet of the purification system.

[0045] In addition to the “bake - out” mode which is a kind of self - cleaning, this system may also provide a self - cleaning mode. In the self - cleaning mode, while the pump 50 is operating, both the drift tube 12 and the sample channel are heated. As an optional aspect, the 24’’ air purification system may also be heated. The air flow is reversed in some areas where contaminants may be generated due to the previous sampling (for example, passing through the desorber). This can assist in removing contaminants from the detector inlet 10. Two such self - cleaning states are provided (state 1 and state 2). In state 1, the flow in the air purification system passes through the first sieve, and in state 2, it passes through the second sieve. In both of these two self - cleaning states, the parts to be cleaned of the IMS such as the drift chamber 12, the reaction area, the detector inlet (or one or more components of the IMS) may be heated. The air flowing “backward” from the reaction area flows into the sampling inlet (for example, flowing in the opposite direction to the air flow during sampling). For this purpose, the air dried using the air purification system is used, and this air is reversed and purified at the inlet of the air purification system.

[0046] The air purification system 24’’ shown in FIG. 2 is capable of performing a bakeout while regenerating one or the other of the two sieves. In the bakeout and regeneration state 2, the system is heated (e.g., one or more components of the IMS to be purified such as the drift chamber 12, the reaction region, and the detector inlet). While this heating is taking place, the air flow of the IMS outside the air purification system is controlled as in the self-cleaning mode described above. However, in this case, the intake valve 80 is switched on so that ambient air is drawn into the system through the air intake port.

[0047] In the state 2 of bake-out + regeneration, both the sieve valves 82 and 84 are switched off, while the discharge valve 86 is switched on. As a result, a part of the purified and dried air supplied to the inlet side of the first one-way valve 90 by the first sieve 70 is sent through the flow impedance orifice to the second port of the second sieve 72. Then, this air "flows backward" through this sieve and reaches the discharge valve. The discharge valve is on, and this flow is discharged outside the air purification system through the evaporator. In this way, while the whole system is in "bake-out", the second sieve can be regenerated by the air sieved by the first sieve. Conversely, in the state 1 of bake-out and regeneration, since both of the two sieve valves are on, the flow from the inlet of the air purification system passes through the second sieve, and a part of it is sent to the outlet of the air purification system by the second one-way valve, and a part of it is sent to the first sieve by the flow impedance orifice. Then, this air "flows backward" through the first sieve and reaches the discharge valve and the evaporator. In this way, it will be understood that while the system is in "bake-out" as a whole, one of the two sieves can be regenerated using the other sieve. At this time, the air containing the "baked-off" contaminants flows into the unregenerated sieve and is purified in the same way as the self-cleaning mode described above. In this method, there is an advantage that it is not necessary to add a pump, and it is also possible to obtain an advantage that it is not necessary to add a drying system such as a membrane that selectively permeates a part of it.

[0048] Other embodiments are also contemplated. For example, although this system has been described as having two molecular sieves, a larger number of sieves may be used.

[0049] Embodiments of the present disclosure provide a modification of an air flow system used to maintain air in a dried and purified state in a detector system. These can be used in detectors based on ion mobility spectrometry, but can also be used in other trace chemical detectors that require a supply of purified and dried air.

[0050] The molecular sieves described herein are not only those used to remove unwanted chemical substances from the gas supplied to the detection device in an IMS or other detection device, but may also be of other suitable types. For example, the molecular sieve may be configured by packing fragments of an absorbent such as zeolite and / or absorbent material into a housing together. For example, the fragment may be, for example, a sphere with a diameter of about 2 mm. The housing is connected to the gas flow path, and the gas flowing through the pack may follow a meandering path around the outside of the fragment of the material, and a part of it may flow through the material. Other types of molecular sieves may be used. For example, a sieve formed of a solid block of molecular sieve material having a plurality of gas flow paths inside may be used. In such a sieve, the flow of gas through the sieve may be limited mainly to the flow passing through the inside of the block. The block may contain zeolite.

[0051] The one-way valves 90, 92 are optional and can be replaced with any suitable flow control means such as an active flow control valve, or a three-way valve as described above may be used. The safety valve 54 described herein is optional and the system may be provided without them. Also, it will be understood in the context of the present disclosure that the functions of the three-way valves 80, 86 shown in FIG. 2 may be provided by any suitable valve such as a simple on / off valve. The flow impedance orifice described so far provides a way to divide the air flow into different parts. As another example, for example, flow division may be achieved by using the balance of pressure losses in different parts of the system. However, for example, (not only the flow orifice but also) other flow controllers, mass flow controllers such as needle valves, pumps, proportional valves, or any other flow control means may be used as any suitable flow controller.

[0052] The bake-out mode described in this specification may differ from the "self-cleaning mode" in that the self-cleaning time may be shorter than the bake-out time, for example, it may be from about 30 seconds to several minutes. In contrast, the bake-out may be longer, for example, it may be scheduled to be performed regularly at night or when the machine is abnormally contaminated and it seems impossible to clean the device with a standard "self-clean". In the self-clean mode, a smaller number of components may be heated than in the case of bake-out. For example, in the bake-out mode, components that take a longer time to cool may be heated, and in the self-clean mode, they may not be heated.

[0053] Any feature found in any of the embodiments disclosed in this specification can be combined with any feature selected from any of the other embodiments described in this specification. For example, the features of a method may be implemented in appropriately configured hardware, and the specific hardware configurations described in this specification may be adopted in methods implemented using other hardware.

[0054] It will be understood from the above discussion that the embodiments shown in the figures are merely illustrative and may include features that can be generalized, deleted, or substituted as described in this specification and as claimed. Generally referring to the drawings, it will be understood that schematic functional block diagrams are used to show the functionality of the systems and devices described in this specification. However, the functions need not be divided as described herein, and it should be understood that the functions do not imply any particular structure other than the hardware structures described in this specification and defined in the following claims. The functions of one or more of the elements shown in the drawings may be further subdivided and / or distributed throughout the devices of the present disclosure. In some embodiments, the functions of one or more of the elements shown in the drawings may be integrated into a single functional unit.

[0055] In some examples, the functions described above may be operated under computer control such that they may be provided by a programmable processor or other such control logic. This may be achieved using a general-purpose processor, which may be configured to execute a method according to any one of those described herein. In some examples, such a controller may be composed of digital logic such as a field programmable gate array, FPGA, application specific integrated circuit, ASIC, digital signal processor, DSP, or any other suitable hardware. In some examples, one or more memory elements may be capable of storing data and / or program instructions used to perform the operations described herein. Embodiments of the present disclosure provide a tangible, non-transitory storage medium containing program instructions that are operable to program a processor to execute any one or more of the methods described and / or claimed herein, and / or to provide a data processing device described and claimed herein. The controller may include an analog control circuit that provides at least a portion of this control function. One embodiment provides an analog control circuit configured to execute any one or more of the methods described herein.

[0056] The above embodiments should be understood as illustrative for purposes of explanation. Further embodiments are contemplated. Any feature described in connection with any one embodiment may be used alone or in combination with any other feature described, and may also be used in combination with any one or more features of any other embodiment, or any one or more features in any arbitrarily combined form of any other embodiment. Furthermore, equivalent forms and modifications not described above may be adopted without departing from the scope of the invention specified in the appended claims.

Claims

1. A method for operating an air purification system of an ion mobility spectrometer, comprising: operating the ion mobility spectrometer in a first sampling mode that includes circulating an air flow in a closed air circulation system that includes a drift chamber of the ion mobility spectrometer and a first sieve of the air purification system; operating the ion mobility spectrometer in a first regeneration mode that includes heating the first sieve while passing a second air flow through the first sieve and sending it to an outlet, and circulating a first air flow through a second sieve of the air purification system and the drift chamber; including wherein, in the first regeneration mode, the second air flow is supplied from the second sieve.

2. The method according to claim 1, wherein, in the first regeneration mode, an ambient air flow is mixed with the air taken in from the ion mobility spectrometer.

3. The method according to claim 1 or 2, wherein, in the first regeneration mode, the second air flow is supplied by a part of the first air flow.

4. The method according to claim 3, wherein a part of the first air flow is diverted from the first air flow using a flow controller such as a flow restrictor like a flow orifice, a mass flow controller such as a needle valve, a pump, a proportional valve, or other flow control means.

5. The method according to claim 4, wherein diverting the first air flow includes operating a discharge valve to enable the second air flow to head towards the outlet.

6. The method according to any one of claims 1 to 5, including switching the ion mobility spectrometer to a second sampling mode that uses the second sieve instead of the first sieve in the closed air circulation system.

7. The method according to claim 6, wherein the ion mobility spectrometer is operated simultaneously in the first regeneration mode and the second sampling mode.

8. The method according to claim 7, wherein the simultaneous operation includes using the first air flow to supply a drift gas required for the operation of the ion mobility spectrometer for analyzing a sample while heating the first sieve to regenerate the first sieve.

9. The method according to any one of claims 1 to 8, comprising switching to a second regeneration mode including heating the second sieve while sending the second air flow through the second sieve to an outlet and circulating the first air flow through the first sieve and the drift chamber of the air purification system.

10. An air purification system for an ion mobility spectrometer, an inlet and an outlet configured to connect the air purification system to a drift chamber of the ion mobility spectrometer to form a closed air circulation system, an outlet for discharging air, a first sieve, a second sieve, and the air purification system is configured to provide a first sampling mode in which air circulates in the closed air circulation system and the first sieve is connected to form part of the closed air circulation system, the air purification system is configured to be switched to a first regeneration mode in which the first sieve is heated while a second air flow passes through the first sieve and is discharged from the ion mobility spectrometer to the outlet, and a first air flow passes through the second sieve and the drift chamber and circulates, In the first regeneration mode, the second air flow is supplied from the second sieve, an air purification system.

11. The air purification system according to claim 10, wherein in the first regeneration mode, an ambient air flow is mixed with the air taken in from the ion mobility spectrometer through the inlet.

12. The air purification system according to claim 10 or 11, wherein in the first regeneration mode, the second air flow is supplied by a part of the first air flow.

13. The air purification system according to claim 12, including a flow orifice configured to divert a part of the first air flow to supply the second air flow.

14. The air purification system according to claim 13, including a discharge valve that can be opened to allow the second air flow to go towards the outlet and can be closed to block the second air flow to the outlet.

15. The air purification system according to any one of claims 10 to 14, further configured to be switched to a second sampling mode in which the second sieve is used instead of the first sieve in the closed air circulation system.

16. The air purification system according to any one of claims 10 to 15, operable in a second regeneration mode in which the second sieve is heated while the second air flow passes through the second sieve and is discharged from the ion mobility spectrometer to the discharge port, and the first air flow passes through the first sieve and the drift chamber and circulates.

17. The air purification system according to claim 16, wherein the air purification system is configured to operate simultaneously in the first sampling mode and the second regeneration mode.

18. The simultaneous operation according to claim 17 includes using the first air flow to supply a drift gas necessary for the operation of the ion mobility spectrometer for analyzing a sample while heating the second sieve to regenerate the second sieve.

19. An ion mobility spectrometer, An air purification system including an inlet and an outlet, the inlet and the outlet being selectively connectable to a first sieve and a second sieve, A drift chamber connected to the outlet and the inlet of the air purification system, the drift chamber being configured such that purified and dried air from the outlet of the air purification system is supplied through the drift chamber, An outlet connected to the air purification system for discharging air from the ion mobility spectrometer, A heater, and The air purification system is configured to regenerate the first sieve by heating the first sieve, changing the flow of air dried by the second sieve, passing it through the first sieve and directing it to the discharge port. An ion mobility spectrometer, wherein the air purification system is configured to regenerate the second sieve by heating the second sieve, changing the flow of air dried by the first sieve, passing it through the second sieve and directing it to the discharge port.

20. During the regeneration of the first sheave, the air dried by the second sheave is also circulated so as to pass through the drift chamber from the outlet of the air purification system and head towards the inlet of the air purification system. The ion mobility spectrometer according to claim 19.

21. During the regeneration of the first sheave, the air circulated through the drift chamber from the outlet of the air purification system is also configured to be used as a drift gas for performing ion mobility spectrometry measurement in the drift chamber. The ion mobility spectrometer according to claim 20.

22. During the regeneration of the second sheave, the air dried by the first sheave is also circulated so as to pass through the drift chamber from the outlet of the air purification system and head towards the inlet of the air purification system. The ion mobility spectrometer according to claim 19.

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