Detector entry apparatus and method

Abstract

An entry device for a detection system and a method for controlling power consumption in a detection system are provided. An inlet device comprises an inlet (102) for receiving a flow of air (108) to be tested, the inlet comprising a heater (106) configured to heat the flow of air to vaporize an aerosol carried by the air for sampling by the analysis device (120). A flow provider (114) is configured to draw the flow of air through the inlet through the heater for sampling by the analytical device, and a controller (104) is configured to control operation of the heater and the flow provider, the flow provider is controlled to provide an aerosol vaporized through the heater for sampling by the analysis device, to reduce the flow rate of the air through the heater to reduce cooling of the heater.

Description

[0001] The present disclosure relates to a detection method and an inlet device for a detector, and more particularly to a method and an inlet device for obtaining a sample for a detector, and still more particularly to a method and an inlet device for providing an evaporated aerosol to a detector. These methods and devices can be particularly applicable to spectrometric analysis, such as ion mobility spectrometry and mass spectrometry.

[0002] Some detectors, such as certain types of ion mobility spectrometers, operate by "drawing in" a gaseous fluid stream, such as air, into the detector inlet and sampling the air with an analytical device to detect a target substance. A sampling port, such as a pinhole, capillary, or membrane inlet, can be used to sample the drawn-in air stream from the detector inlet.

[0003] Some analytical devices, and particularly certain ion mobility spectrometers, are suitable for analyzing vapors and gases. These analytical devices can be configured to detect target substances, such as anesthetics, explosives, and chemical warfare agents. Therefore, the detection sensitivity and reliability of these detectors may become critical issues. Certain target substances may include aerosols. Unlike vapors or gases, aerosols include fine particles of solids or liquids suspended in a gas. For substances with a low vapor pressure, the ion mobility spectrometer may not be able to detect the particles of the substance in the aerosol without evaporation.

[0004] Generally, for example, military and security personnel may need to use handheld or portable devices, which may require smaller size, weight, and complexity compared to other detectors. Generally, these devices are battery-powered and require an extended battery life.

[0005] Various aspects and embodiments of the present disclosure are directed to solving the above technical problems. Summary of the Invention

[0006] Embodiments of the present disclosure relate to a detector inlet for providing a sample to an analytical device for detecting a target substance. Detectors, such as mass spectrometers and ion mobility spectrometers, can be configured to ionize a vapor and then analyze the ions generated from the vapor to detect a target substance. Such a detector can be configured to draw in a gaseous fluid stream from the environment to be tested and then sample from the stream. Thereafter, the sample can be tested to detect the presence of the target substance. The gaseous fluid can include gases, such as air, vapors, and aerosols, for example, solid or liquid particles suspended in the gaseous fluid.

[0007] An analysis device configured to analyze a vapor sample can analyze the vapor present in a directly sampled environment. However, it may be necessary to heat an aerosol-containing air stream to evaporate the aerosol in the environment, which facilitates effective analysis of the evaporated aerosol. A heater can be placed in the path of the sample drawn into the inlet of the detector to heat the sample to evaporate the aerosol. However, by drawing the air stream used for sampling through the heater, the heater itself is cooled by the passing stream. Due to the cooling effect of the air stream, either a large amount of power is required to bring the heater to the temperature required for aerosol evaporation, or the amount of aerosol evaporation will decrease in synchronization with the detection sensitivity of the aerosol.

[0008] Embodiments of the present disclosure aim to solve such problems by controlling the heating and the stream passing through the detector inlet to reduce the power requirement and allow effective heating to an ideal level that can provide the amount of aerosol evaporation. In particular, by reducing the flow rate of the air passing through the heater before increasing the power of the heater, the cooling effect of the air passing through the heater can be reduced while the heater is raised to the temperature for aerosol evaporation. Therefore, for a given power supplied to the heater, by reducing the stream passing through the heater, the temperature of the heater can be higher. In this way, the power required to evaporate the aerosol can be reduced, or for a given power output, the temperature of the heater can be higher while increasing the amount of evaporation, and the sensitivity for detecting non-volatile aerosol can be increased. In addition, when the stream is reduced, at a lower flow rate, a portion of the stream stays around the heater for a longer time, thus heating the air near the heater and the carried aerosol more effectively.

[0009] The various aspects of the present disclosure will be set forth in the independent claims, and the optional features will be set forth in the dependent claims. The various aspects of the present disclosure can be combined with each other, and the features of one aspect can be applied to other aspects.

[0010] On the one hand, an inlet device for a detection system is provided, the device comprising: an inlet for receiving an air stream to be tested, the inlet including a heater configured to heat the air stream to evaporate aerosols carried by the air for sampling by the analysis device; a flow provider configured to draw the air stream through the inlet past the heater for sampling by the analysis device; and a controller configured to control the operation of the heater and the flow provider such that the flow rate of the air passing through the heater is reduced to reduce cooling of the heater before increasing the power of the heater to evaporate the aerosols, and the controller is further configured to control the flow provider to provide the aerosols evaporated by the heater for sampling by the analysis device.

[0011] The inlet device may be configured to provide vapors present in the air drawn into the inlet and the evaporated aerosols to the analysis device. For example, the controller may be configured to operate the device to detect vapors and aerosols by: drawing a first air stream into the inlet with the heater off, and providing the first air stream for sampling by the analysis device before reducing the flow rate of the air passing through the heater. As will be appreciated, a first air stream may still be drawn into the inlet with the heater off. In some embodiments, the heater may alternatively be operated at a lower power than the power used to evaporate the aerosols (e.g., to reduce deposition of substances in the inlet), and the power is increased after the flow is reduced to evaporate the aerosols. The analysis device may be configured to obtain a sample from the first air stream to detect vapors in the first air stream. In this way, relatively volatile vapors that do not need to be heated in the inlet can be provided to the analysis device before power is provided to the heater to evaporate the aerosols for detection. When heating a vapor sample at the inlet of the detector, the sensitivity of the detector for detecting the vapor may be reduced in some cases. Therefore, it may be desirable to sample the vapors drawn into the inlet without providing power to the heater. However, drawing this air stream into the inlet past the heater will cool the heater as it passes through, and this will result in increased power consumption to bring the heater to the required temperature with the heater subject to this flow. Therefore, by sampling the vapors before increasing the power of the heater and then reducing the flow, effective sampling of vapors in addition to aerosols can be achieved while reducing the power requirements of the device.

[0012] To provide an aerosol for detection, the device can be configured to draw an air stream into the inlet after a power boost of the heater to evaporate the aerosol in the stream drawn through the heater. Thus, after increasing the power of the heater and decreasing the flow rate, the controller can be configured to control the device to draw a second air stream into the inlet through the heater to evaporate the aerosol in the second air stream and thus provide the evaporated aerosol for sampling by the analysis device. Thus, the second air stream can include a sample drawn from outside the inlet or from the inlet upstream of the heater, and after the heater reaches the desired temperature, the second air stream is drawn through the heater to evaporate the aerosol. The analysis device can be configured to obtain a sample of the evaporated aerosol from the second air stream for detecting the aerosol in the second air stream.

[0013] In some cases, the evaporated aerosol provided to the analysis device for sampling can include the aerosol present in the heater perimeter, which evaporates during the time when the heater rises to the desired temperature. For example, in the case where the heater is heated to the desired temperature while the flow stops, the aerosol near the heater can evaporate when the flow stops and be provided to the analysis device when the flow resumes.

[0014] Providing the evaporated aerosol for sampling by the analysis device can suitably include: providing a flow through the inlet to convey the evaporated aerosol from the heater to the analysis device for sampling (e.g., controlling the flow provider to provide the flow). Providing the evaporated aerosol for sampling by the analysis device includes: operating the flow provider to increase the flow rate through the inlet.

[0015] In some embodiments, decreasing the flow rate of the air passing through the heater includes: providing a reduced flow rate, and providing the evaporated aerosol for sampling by the analysis device includes: maintaining the reduced flow rate so as to convey the evaporated aerosol from the heater to the analysis device (e.g., to a sampling port downstream of the heater, through which the analysis device obtains a sample from the inlet).

[0016] In some embodiments, decreasing the flow rate of the air passing through the heater can include: causing the flow provider to stop providing the flow through the inlet. After the heater is powered to provide the desired temperature, the flow provider can then be operated to increase the flow rate through the inlet, thus providing the evaporated aerosol for sampling by the analysis device. As described above, depending on the time of sampling by the analysis device, the sampled evaporated aerosol can be the aerosol drawn into the inlet after the flow is increased, or can be the aerosol that was already present in the inlet when the heater was turned on.

[0017] The controller can be configured to: after the heater reaches a threshold temperature and / or after a fixed time delay after the heater is turned on, operate the flow provider to supply the evaporated aerosol to the analysis device. The temperature of the heater can be measured or appropriately inferred based on the following information: the power supplied to the heater and / or the time since the heater was turned on for a specific flow rate of air through the inlet. The time for providing the evaporated aerosol for sampling can be based on the time delay after the heater is powered, to allow the heater to reach the desired temperature. In some cases, this time can vary based on the environmental conditions used by the detector. For example, depending on the ambient temperature, in some cases, the time delay before sampling can be adjusted based on a known relationship between the time for the heater to reach temperature and the ambient temperature.

[0018] As described above, the inlet includes a heater. The heater can be disposed within the inlet or at least partially disposed within the inlet, such as at the entrance of the inlet. In some such examples, one or more inner walls of the inlet can include the heater. The heater can include a conductor, such as a heat-conductive wire, which can be arranged to be heated by resistive heating. The heat-conductive wire can include a metal. The heater can be arranged in a grid or mesh pattern to provide an obstruction in the inlet, such that the air flowing through the inlet flows through or around the heater. Preferably, the heater includes a heat-conductive wire arranged in the path of the air flow in the inlet, such that the air flow must pass through the heat-conductive wire to reach the analysis device.

[0019] In an embodiment, the heater can include a single array of heat-conductive wires, such as parallel heat-conductive wires or an array of heat-conductive wires passing through the inlet along a curved or wound path (e.g., a sinuous path). In a preferred embodiment, the heater can be configured to allow the flow through the inlet to pass through the heater while minimizing the capture of aerosol and vapor located on the heater. The heater can include an elongated conductor, such as a resistively heated heat-conductive wire, which is arranged across the inlet (e.g., extending across the inlet perpendicular to the flow direction through the inlet) in the flow path through the inlet. The heater can include an array of elongated conductors arranged across the inlet, such as an array of elongated conductors that can be arranged in a plane perpendicular to the flow direction through the inlet. The thickness of the conductor (e.g., heat-conductive wire) and the gap between the conductors can be selected to minimize the capture of aerosol located on the heater. The heater can include more than one array of conductors, such as more than one array of conductors arranged in corresponding planes offset from each other along the flow direction. In other embodiments, the heater can include a braided structure, such as a stacked or bundled heat-conductive wire. An example of such a structure includes a braided mesh heat-conductive wire, such as a braided mesh (RTM).

[0020] The heater structure can be arranged such that the ratio of the volume occupied by the heating wire is less than 80%, in some examples less than 60%, in some examples less than 40%, and in some examples less than 20% of the volume is occupied by the heating wire, and the remaining volume can be occupied by an air space that allows the air to be heated to flow. In one embodiment, at least 60% of the structure volume is air, and in some embodiments, approximately 70% of the structure volume is air. Using a lower density can achieve improved efficiency and sensitivity of the device by heating the air flow. The heater can be provided with a constriction in the second sampling path, or the heater can be arranged to surround a constriction in the path of the second air flow. In some examples, the heater can include an infrared light source, such as an infrared lamp or LED, or an infrared laser. In some examples, the heater can include one or more hot air jets that inject hot air into the second air flow in the second sampling path before the air flow is provided to the analysis device for sampling.

[0021] The heater can be configured to heat the air flow to a temperature of at least 150 °C to evaporate the aerosol, for example at least 200 °C, and / or wherein the heater is configured to heat the air flow to a temperature not exceeding 300 °C, for example not exceeding 250 °C. Thus, the heater can be configured to heat the air flow to a temperature of 150 °C to 300 °C, for example 200 °C to 250 °C.

[0022] The cooling effect of the flow passing through the heater via the inlet will depend on the flow velocity or rate of the flow. The flow velocity passing through the heater via the inlet before reducing the flow velocity is at least 0.4 m / s, for example at least 0.6 m / s. When the heater is turned on, the flow velocity passing through the heater via the inlet is less than 0.4 m / s, for example less than 0.3 m / s. Preferably, the flow rate for the evaporated aerosol for sampling through the analysis device (e.g., for transporting the evaporated aerosol from the heater to the analysis device) is at least 0.17 m / s, for example at least 0.25 m / s.

[0023] The volumetric flow rate through the inlet will vary based on the cross-sectional area of the inlet. In an embodiment, the flow rate through the heater via the inlet before reducing the flow rate can be at least 400 ml / min, such as at least 600 ml / min, for example at least 800 ml / min. In some preferred embodiments, the flow rate through the inlet before reducing the flow rate can be 800 to 1200 ml / min, such as about 1000 ml / min or greater. When the heater is on, the flow rate through the heater via the inlet is preferably less than 400 ml / min, for example less than 300 ml / min. The flow rate for providing the evaporated aerosol for sampling by the analytical device (e.g., for transporting the evaporated aerosol from the heater to the analytical device) is preferably at least 200 ml / min, for example at least 300 ml / min.

[0024] As described above, the flow rate / rate for providing the evaporated aerosol for sampling by the analytical device can correspond to the reduced flow when the heater is on, or can be higher, such as corresponding to the flow rate / rate before reducing the flow rate.

[0025] The inlet may suitably include one or more sampling ports, and the analytical device may be configured to obtain a sample from the inlet through the one or more sampling ports. For example, the one or more sampling ports may be individually selected from a pinhole inlet, a capillary inlet, or a membrane inlet. The analytical device may be configured to obtain a sample from the inlet in any suitable manner, such as by pulsing a sampler (such as a pump) to draw a sample from the inlet through the one or more sampling ports.

[0026] The inlet device may be configured to provide an air flow through the inlet past the heater and then past the one or more sampling ports. Thus, the inlet may include an opening for receiving the air flow to be sampled, where the device is configured to draw the air flow from the opening, past the heater, and then through the one or more sampling ports to an exhaust outlet. The flow provider may suitably be provided downstream of the one or more sampling ports so as to draw a flow through the inlet past the heater and then through the one or more sampling ports.

[0027] In some cases, the device can be used in the presence of dust, coarse sand, and other particulate matter. These particles may impede or otherwise damage or contaminate the detector. The inlet device can be configured to remove particles from the flow upstream of the inlet while transporting vapor and aerosol to the inlet, for example, by providing a tortuous flow path from an opening to the ambient atmosphere outside the detector to the inlet, which tortuous flow path prevents or reduces the proportion of particles reaching the inlet. In an embodiment, the detector is configured such that the flow provider draws the flow to be sampled past the one or more sampling ports of the analysis device to allow sampling of the vapor in the flow while drawing particulate matter present in the flow past the one or more sampling ports without entering the one or more sampling ports. Although the analysis device is configured to sample vapor, some particulate matter or aerosol may still enter the one or more sampling ports. However, the one or more sampling ports can be arranged to reduce the proportion of particulate matter or aerosol drawn through the sampling ports when sampling vapor. For example, the one or more sampling ports can be configured to draw samples into the analysis device in a direction orthogonal to the direction of the overall flow through the inlet to reduce the entry or blockage of particles into the sampling ports. The inlet may suitably include a sampling volume from which the one or more sampling ports draw samples for analysis by the analysis device. For example, the sampling volume can be a volume adjacent to the one or more sampling ports of the inlet. In an embodiment, the inlet can include one or more deflectors configured to change the particle distribution within the sampling volume to increase the proportion of particles that pass by the sampling ports without being drawn into the sampling ports. For example, the deflector can include a change in the cross-section of the inlet, including a change in the flow direction within the sampling volume or the inlet, to provide a volume adjacent to the sampling ports where the proportion of particle presence can be reduced. For example, the deflector can project from the wall of the inlet, where the sampling ports are arranged on the wall of the inlet downstream of the deflector. Alternatively, the sampling ports can be arranged on the inside of a bend in the inlet or at the center of a circulating flow within the inlet such that centrifugal effects reduce the proportion of particles in the region adjacent to the sampling ports.

[0028] On the other hand, a detector is provided that includes an inlet device as described herein and an analysis device configured to obtain a sample from the inlet to detect a target substance. It should be understood that any component or controller of the detector can be adapted as described elsewhere herein with respect to the inlet device.

[0029] The controller can be configured to synchronize the operation of the analysis device with the operation of the flow provider and / or the heater to obtain a sample of the evaporated aerosol provided from the heater to the analysis device by the flow provider.

[0030] The analysis device can be configured based on the time of obtaining a sample from the inlet to: sample the evaporated aerosol drawn into the inlet after heating the heater to a certain temperature, or can be configured to sample the evaporated aerosol adjacent to the heater when the heater is turned on. For example, in the following embodiments, when the flow stops or is low enough when the heater is turned on, while the heater is heated to the desired temperature, the heater can also evaporate the aerosol present near the heater. Alternatively or additionally, the sampling time of the analysis device can be delayed such that the aerosol drawn into the inlet is transported past the heater and evaporated after the heater reaches the desired temperature. Subsequently, the flow through the inlet, such as an elevated flow, can then transport the evaporated aerosol through the inlet for sampling by the analysis device. It should be understood that the time and flow rate at which the evaporated aerosol sampled through one or more sampling ports reaches the analysis device will determine whether the sampled evaporated aerosol is drawn from outside the inlet past the heater after the heater temperature rises, or was present when the heater was turned on.

[0031] Preferably, the detector is a portable detector including a portable power source, such as a handheld detector. As will be understood, in the case of using a portable power source that may have limited capacity, the power savings obtained by reducing the flow through the heater as described herein may be particularly beneficial. The portable power source can include a battery, a fuel cell, a capacitor, or any other portable power source suitable for supplying power to the detector.

[0032] The detector can be appropriately configured to draw the air flow from the surrounding environment where the detector is located. For example, the detector can be configured to detect: a target substance in the air of the surrounding environment in which the detector operates (rather than drawing a flow to be sampled from another device such as a chromatography device or a pre-collected sample).

[0033] The analysis device can include any suitable analyzer for detecting a target substance in vapor form. The analysis device can include at least one of the following: an ion mobility spectrometer (IMS), a differential mobility spectrometer (DMS), a mass spectrometer (MS), a chromatography device (such as a gas chromatography system), and an optical spectrometer (such as an infrared spectrometer or a Raman spectrometer). In an embodiment, the analysis device can include an ion mobility spectrometer, a mass spectrometer, or a combined IMS-MS. The IMS can include positive IMS and / or negative mode IMS. In an embodiment, the analysis device includes a positive mode IMS and a negative mode IMS configured to analyze a sample from a single sampling body. In some embodiments, a single IMS can switch between the positive mode and the negative mode and can be configured to quickly switch between the positive mode and the negative mode in order to analyze a single sample in both the positive mode and the negative mode simultaneously.

[0034] The controller can be configured to receive the following indications from the analysis device: the target substance is detected or not detected, and the controller is configured to provide an indication to the user, such as an alarm to the user that the target substance is detected.

[0035] In some embodiments, the operating parameters of the analysis device and / or the parameters for data analysis can be selected based on the sampling time. For example, vapor sampling and aerosol sampling can be aimed at detecting different target substances, and the operating parameters of the analysis device such as a mass spectrometer can be controlled to achieve or improve the detection of the target substance. For example, depending on whether a target vapor or a target evaporative aerosol is desired to be detected, which will result in one or more specific peaks in the mass spectrum, the operating parameters of the mass spectrometer or the analysis of the obtained data can be controlled to focus on the relevant peaks, and / or exclude mass spectral regions that are not relevant to the expected target substance. Thus, the operating parameters of the analysis device can be independently selected to facilitate sampling of the vapor (e.g., in a first air stream) and to facilitate sampling of the aerosol (e.g., in a second air stream).

[0036] On the other hand, a method for controlling power consumption in a detection device for analyzing vapors and aerosols is provided, the method comprising the following steps performed sequentially: (i) drawing a first air stream through an inlet of the device; (ii) sampling the first air stream to detect a target vapor present in the first air stream; (iii) reducing the flow rate of the air drawn through the inlet to reduce cooling of a heater provided in the inlet; (iv) increasing the power to the heater to bring the heater to a temperature for evaporating the aerosol in the inlet; (v) drawing a second air stream through the inlet past the heater to transport the evaporated aerosol for sampling; and (vi) sampling the evaporated aerosol to detect the aerosol present in the second air stream.

[0037] The first air stream can be drawn through the inlet at a first flow rate, and the second air stream can be drawn through the inlet at a second flow rate. As will be understood, the first and second streams refer to portions of the flow passing through the same inlet, e.g., flows provided through the same inlet at different times.

[0038] The first flow rate can be higher than the second flow rate. For example, the first flow rate can be drawn through the inlet for vapor sampling and reduced before increasing the power to the heater, and the second flow rate is maintained at the reduced flow rate or higher than the reduced flow rate but lower than the first flow rate.

[0039] Thus, in some embodiments, the second flow rate corresponds to the reduced flow rate provided in step (iii).

[0040] The second flow rate may be higher than the reduced flow rate provided in step (iii), for example, wherein the second flow rate substantially corresponds to the first flow rate. In embodiments where the second flow rate corresponds to the first flow rate, the operation of the flow provider can be simplified because such embodiments can operate at two flow rates, one flow rate for moving air through the inlet to provide vapor for sampling by the analysis device, and one reduced flow rate.

[0041] Sampling the first air flow and the second air flow may include: drawing a sample into one or more sampling ports of the analysis device. As previously described, the one or more sampling ports may be selected from a pinhole inlet, a capillary inlet, or a membrane inlet, preferably a pinhole inlet. A sample can be drawn through the one or more sampling ports by any suitable sampler, such as a sampler configured to reduce the pressure on the downstream side of the sampling port to draw a volume of air through the sampling port.

[0042] Sampling the vapor in the inlet into the analysis device through the one or more sampling ports can be timed based on information such as when the heater is turned on and / or when the second flow is provided through the inlet. For example, sampling the evaporated aerosol through the one or more sampling ports can be performed after the power of the heater is increased and / or after the flow through the inlet is increased for a fixed period of time, so that the second air flow passes through the heater to the one or more sampling ports.

[0043] The second air flow can be heated to a temperature of at least 150 °C to evaporate the aerosol, for example at least 200 °C, and the temperature can also be controlled to save power and avoid overheating the inlet. Therefore, the second air flow can be heated to a temperature not exceeding 300 °C, for example not exceeding 250 °C. Therefore, the second air flow can be heated to a temperature of 150 °C to 300 °C, for example 200 °C to 250 °C.

[0044] The flow rate and / or velocity of the first air flow and / or the second air flow can be appropriately as described previously. For example, the flow rate of the first air flow and / or the second air flow passing through the heater can be at least 0.4 m / s, for example at least 0.6 m / s, and the reduced flow rate can be less than 0.4 m / s, for example less than 0.3 m / s.

[0045] It should be understood that the detector mentioned with respect to this method may include a detector or an inlet device as described elsewhere herein, and the method may include the control of the detector or the inlet device as described previously herein. For example, the method may include the operation of the detector or the inlet device and the controller as described herein. For example, the method can be implemented by a controller according to instructions stored in the memory of the controller.

[0046] The controller described herein may be provided appropriately by any suitable control logic, such as an analog control circuit and / or a digital processor, examples including a field programmable gate array, FPGA, application specific integrated circuit, ASIC, digital signal processor, DSP, or provided by software loaded into a programmable processor. Various aspects of the present disclosure include computer program products and may be recorded on a non-transitory computer-readable medium, and these aspects may operate to program a processor to perform any one or more of the methods described herein.

[0047] On the other hand, there is provided a computer program product configured to program a controller of a detection device to perform any of the methods described herein, or a fixed logic circuit configured to control a detection device to perform any of the methods described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Reference will now be made to the drawings, which illustrate examples of the present disclosure by way of example only, in which:

[0049] Figure 1 A schematic diagram of a detector is shown, which includes an ion mobility spectrometer coupled to an inlet of an inlet device detector;

[0050] Figure 2 A schematic diagram of an inlet of a detector including an analysis device is shown, the analysis device including two mass spectrometers connected to the detector inlet;

[0051] Figure 3 The results of changing the flow rate and heater power in the detector inlet are shown; and

[0052] Figure 4 A method for controlling power consumption in a detection device is shown.

[0053] In the drawings, the same reference numerals are used to denote the same elements. DETAILED DESCRIPTION

[0054] The present disclosure relates to a detector inlet including a heater for evaporating an aerosol and reducing the power requirements of the heater.

[0055] Figure 1There is shown a detection device 100 including a detector inlet 102 and an analysis device including a mass spectrometer 120 having a sampling port 112 for obtaining a sample for analysis from a sampling body 110 into the mass spectrometer 120. The inlet includes a heater 106 disposed in an air path through the inlet 102. Downstream of the heater 106, the inlet 102 includes the sampling port 112 provided by a pinhole member. The inlet 102 includes a flow channel configured to provide an air flow drawn through the inlet 102 from the ambient atmosphere outside the detector by a flow provider 114, the air flow passing through the heater 106 and then through the sampling port 112 to an exhaust port 116. The heater 106 is configured to heat the flow through the inlet so as to evaporate the aerosol in the flow passing through the heater 106. Then, the flow provider 114 can draw a flow containing the evaporated aerosol 108 through the inlet. The flow containing the evaporated aerosol 108 passes through the sampling body 110 adjacent to the sampling port 112 such that the analysis device 120 can obtain a sample from the flow containing the evaporated aerosol 108.

[0056] The inlet device includes a controller 104 configured to control the heater 106 and the flow provider 114. The controller 104 is configured to control the flow provider 114 to reduce the flow rate of the air passing through the heater 106 through the inlet 102, which reduces the cooling of the heater 106 by the passing flow. After the flow rate is reduced to evaporate the aerosol in the inlet 102, the controller 104 increases the power supplied to the heater 106. Then, the evaporated aerosol carried in the flow 108 is sent to the sampling body 110, and the controller controls the analysis device 120 to obtain a sample from the sampling body through the sampling port 112. The flow for transporting the evaporated aerosol 108 is provided by the flow provider 114. For example, after the heater 106 has been heated to a desired temperature, the flow provider 114 can increase the flow rate through the inlet so as to draw the air flow passing through the heater 106 into the sampling body 110.

[0057] Device 100 can be configured to sample vapors and aerosols present in the stream drawn into inlet 102. For example, controller 104 can operate the device such that when heater 106 is off, a first air stream is drawn into inlet 102. The first stream provided by stream provider 114 flows through heater 106 to sampling body 110. Then, controller 104 controls analysis device 120 to draw a sample including the vapor to be analyzed from sampling body 110 into analysis device 120 for analysis. Then, controller 104 reduces the flow rate of the air through inlet 102, thereby reducing the cooling effect of the air passing through heater 106 before increasing the power of heater 106 to bring the heater to the desired temperature. Stream provider 114 is controlled to provide a second air stream through inlet 102 through power heater 106 to evaporate the aerosol in the second air stream. Stream provider 114 can increase the stream rate to transport the evaporated aerosol to sampling body 110 for sampling, or, if the reduced stream rate is sufficient, the reduced stream can transport the evaporated aerosol to the sampling body for analysis by the analysis device.

[0058] Device 100 can be portable, such as a hand-held detector, and can include a portable power source 118 that can be carried by the detector. The portable power source can include a battery, a fuel cell, a capacitor, or any other portable power source suitable for providing electrical power to the detector. Although portable power source 118 is shown connected to controller 104, it will be understood that the portable power source can provide power to any component of detection device 100.

[0059] In Figure 1 , mass spectrometer 120 includes an ion mobility spectrometer coupled to sampling body 110 through sampling port 112 and includes a reaction region 122 in which the sample can be ionized. Sampling port 112 can be used to provide a sample from sampling body 110 into mass spectrometer 120. Grid electrode 126 can separate reaction region 122 from a drift chamber 128. Drift chamber 128 includes a collector 136 that faces an end of drift chamber 128 opposite grid electrode 126. In other embodiments, the ion mobility spectrometer can operate with an ion trap that holds and releases sample ions in place of grid electrode 126. Drift chamber 128 also includes a drift gas inlet 134 and a drift gas outlet 132, and drift gas outlet 132 is arranged to provide a drift gas flow in a direction opposite to the movement of the sample ions toward collector 136 along drift chamber 128, e.g., a drift gas flow from collector 136 toward grid electrode 126. Sampling port 112 can be used to sample air from sampling body 110 into reaction region 122 of mass spectrometer 120. Reaction region 122 includes an ionizer 124 for ionizing the sample. InFigure 1 In the example shown, the ionizer 124 includes a corona discharge ioniser that contains electrodes. It will be understood that other ionization power sources may also be used. The drift chamber 128 also includes a drift electrode 130 for applying an electric field along the drift chamber 128 to accelerate ions towards the collector 136 against the flow of the drift gas. The detector may include a sampler (not shown) configured to extract a selected volume of fluid smaller than the sampling volume 110 through the sampling port 112 to provide a sample to the analysis device. The sampler may include an electromechanical actuator, such as a solenoid-driven actuator, and / or a mechanical pump arranged to transfer the vapor from the sampling volume 110 through the sampling port 112 into the analysis device / mass spectrometer 120.

[0060] The device 100 includes a flow provider 114 for drawing air through the inlet 102 and past the heater 106 and one or more sampling ports 112 of the analysis device. As Figure 1 shown, the flow provider 114 is provided with an exhaust flow 116 downstream of the sampling volume 110 and the sampling port 112. The flow provider 114 may be configured, for example, as a pump, or a fan, or any device suitable for drawing an air flow through the inlet past the heater 106 to the sampling volume 110. In some cases, the flow provider 114 may itself not be part of the detector and may be provided separately and may be connectable, for example, to the inlet 102 to provide a flow through the inlet 102.

[0061] As Figure 1 shown, the device 100 includes a controller 104 configured to control the operation of the device. For example, the controller may be coupled to the heater 106, an analysis device such as the mass spectrometer 120, and the flow provider 114, for example, to control or be in electrical communication with each of the above. The controller 104 may include a processor and a memory storing instructions for the operation of the device 100.

[0062] The controller 104 may be configured to operate the device 100 in response to an activation signal, which may be provided by a user or an automatic activation signal, such as a signal provided according to a preconfigured time (e.g., intermittently at a fixed frequency).

[0063] The controller 104 can be configured to control the heat output of the heater 106 to vary the temperature and / or duration of heating. In some embodiments, the controller 104 can be configured to control the heater 106 and the flow provider 114 to desorb residues that may have accumulated in the inlet 102 or on the heater 106. For example, the controller 104 can be configured to activate the heater 106 for a first time period and draw air through the inlet 102 so that the desorbed material from the inlet 102 can leave the inlet via the exhaust stream 116. In some cases, desorption of the material in the inlet can be combined with evaporation of the aerosol for sampling. For example, the flow through the inlet 102 can be reduced as described above, and power can be provided to the heater 106, and then the flow through the inlet 102 can be provided for the first time period and the desorbed material is allowed to leave the inlet. Then, after the first time period has elapsed, while the flow provider 114 continues to draw air through the inlet 102 past the heater 106, the air drawn past the heater 106 is heated to evaporate the aerosol in the air for sampling by the analytical device / mass spectrometer 120. Thus, the flow through the inlet 102 can flush the desorbed material out of the detector to prepare for testing the aerosol of the air sample. During sampling of the second air stream to evaporate the aerosol, the heat output of the heater 106 can be less than the heat output used to desorb the residues during the first time period. For example, after the first time period and when the heater is cooling, the heater 106 can be controlled to reduce the power provided to the heater 106, such as by turning it off.

[0064] As Figure 1 and 2 shown, the inlet 102 includes a flow channel that is arranged to receive an air flow from an opening (not shown) for receiving air from the ambient atmosphere external to the device 100. The inlet 102 is shown as being provided by a conduit, such as a hose or pipe. However, the inlet 102 can also be provided by channels and air chambers that are cut into a block of material and then enclosed. In Figure 1 and 2 the example shown, the inlet can be less than 20 mm wide. For example, less than 10 mm wide, for example, less than 5 mm, for example, less than 2 mm, for example, less than 1.5 mm, for example, less than 1 mm, for example, less than 0.75 mm, for example, less than 0.5 mm, for example, less than 0.4 mm, for example, less than 0.3 mm, for example, less than 0.2 mm, for example, less than 0.1 mm. In Figure 1 and 2In the example shown, the inlet 102 can be at least 10 micrometers wide, such as at least 0.1 mm wide. For example, at least 0.2 mm, for example, at least 0.3 mm, for example, at least 0.4 mm, for example, at least 0.5 mm, for example, at least 0.75 mm, for example, at least 1 mm, for example, at least 1.5 mm, for example, at least 2 mm, for example, at least 5 mm wide.

[0065] As Figure 1 and 2 shown, the device 100 can be configured such that the flow provider 114 draws an air flow to be sampled through one or more sampling ports 112 of the analysis device to allow sampling of vapors in the flow, while drawing particulate matter present in the flow through one or more sampling ports 112 without entering the one or more sampling ports 112. As Figure 1 and 2 schematically shown, the sampling port 112 is configured to draw a sample into the analysis device in a direction orthogonal to the direction of the overall flow through the sampling body 110 to the exhaust port 116 to reduce particulate entry or blockage of the one or more sampling ports 112.

[0066] Although Figure 1 an ion mobility spectrometer is described, the analysis device can include any suitable device for analyzing vapors and evaporating aerosols. The analysis device can include, for example, at least one of the following: an ion mobility spectrometer (IMS), a differential mobility spectrometer (DMS), a mass spectrometer (MS), a chromatography device (such as a gas chromatography system), and an optical spectrometer (such as an infrared spectrometer or a Raman spectrometer).

[0067] Figure 2 Shows the device 100 as Figure 1 shown, where the analysis device includes two mass spectrometers 120, which have two corresponding pinhole sampling ports 112. The two mass spectrometers 120 can include, for example, a positive mode IMS and a negative mode IMS. In cases where the analysis device includes more than one separate analytical instrument, such as mass spectrometers, these analytical instruments can be the same or different in structure and / or operation. For example, both can be IMS instruments configured to operate in different ways, such as in positive and negative modes, or the two instruments can be different instruments, such as an IMS and a mass spectrometer.

[0068] Although in Figure 2The two sampling ports 112 shown in the figure are separated along the overall flow direction from the inlet 102 to the exhaust port 116, but any suitable arrangement can be used according to the requirements and internal structure of the device 100. For example, the two sampling ports 112 (and the corresponding mass spectrometers 120 in the embodiment) can be separated around the outer periphery or circumference of the flow channel including the sampling body 110. For example, the sampling ports 112 can each be at approximately the same distance from the heater 106, such as being disposed on opposite sides of the flow channel or adjacent to each other on the wall of the inlet and separated in a direction perpendicular to the overall flow direction. Although not shown in Figure 2 for clarity, it should be understood that there may be Figure 1 a controller 104, a portable power supply 118, and other components, and the controller 104 can be coupled to Figure 2 the two mass spectrometers 120 in the figure and control their operations.

[0069] Although Figure 1 and 2 the devices shown in the figure provide embodiments of the present disclosure, other embodiments can be considered.

[0070] Figure 3 The experimental results of the measured temperature of the heater disposed in the detector inlet as described herein are shown at different power levels and different flow rates through the inlet. The heater includes two heating elements, and the heating elements include an array of resistively heated elongated heat-conducting wires, and the array is arranged to span the inlet and is separated in the flow direction through the inlet. The temperature of the first upstream heater (at the opening where the inlet leads to the external atmosphere) is measured using a thermal camera aligned with the inlet. The temperature is measured as the average temperature across a fixed square area at the center of the cross-section of the heater in the inlet. It should be noted that Figure 3 the temperature shown corresponds to the temperature in front of the first heating element, so the temperature of the air passing through the heater will be heated to a temperature higher than Figure 3 the temperature shown.

[0071] The flow through the inlet past the heater is measured and varied using a mass flow controller, and is varied from 0 ml / min to 1000 ml / min (which corresponds to a flow rate of 0.85 m / s). At each flow rate, the power supplied to the heater is varied from the lowest power ( Figure 3 DAC 0 in the figure) to the highest power ( Figure 3 DAC 14000 in the figure). In Figure 3 the figure, as shown by the key part in the figure, the flow rate is also shown by different columns in the figure.

[0072] Figure 3The "DAC" numbers shown correspond to the relative power supplied to the heater controlled by the parameters of the digital-to-analog converter, with respect to which DAC 0 corresponds to approximately 7.5 W.

[0073] As Figure 3 shown, for a constant power applied to the heater, the average temperature of the heater can be increased by reducing the flow through the heater. Similarly, by reducing the flow through the heater, a lower power is required to achieve a given heater temperature. As Figure 3 shown, at lower relative power levels, reducing the flow through the inlet has a particularly strikingly significant effect on the heater temperature. Thus, by reducing the flow through the inlet before supplying power to the heater in the inlet as described herein, a significant amount of power can be saved for heating the aerosol in the inlet of the detector.

[0074] Figure 4 A method 400 for controlling power consumption in a detection device for analyzing vapors and aerosols is shown. As Figure 4 shown, the method includes 402 drawing a first air flow through an inlet. The air flow can be appropriately drawn into the inlet through an opening in fluid communication with the ambient atmosphere external to the detector, through a heater disposed in the inlet, through one or more sampling ports of the analysis device, and to an exhaust port. When the heater is off, the first air flow can flow through the inlet past the heater and through one or more sampling ports downstream of the heater. In step 404, the vapor in the first air flow can be sampled via one or more sampling ports for analysis, and the analysis device can be operated to analyze the vapor to detect a target substance. Analyzing the vapor can include ionizing the vapor and analyzing the resulting ions in an IMS as described above, although any other suitable analysis technique can alternatively or additionally be performed.

[0075] In step 406, after the vapor in the sampled ambient atmosphere has been drawn into the inlet together with the first air stream for analysis, the flow rate through the inlet is reduced to reduce the cooling effect of the stream on the heater. While reducing the stream, in step 408, the power to the heater is increased, thereby increasing the temperature of the heater to evaporate the aerosol. As the power is increased, the aerosol near the heater can be evaporated to provide the evaporated aerosol. In step 410, a second air stream is drawn through the inlet. The second stream can include aerosol drawn from the ambient atmosphere into the inlet and evaporated by the heater as they flow past the heater. When the heater is turned on, the second air stream can also transport the aerosol evaporated in the inlet to one or more sampling ports for sampling. As previously described herein, the second stream can include an increased flow rate compared to the reduced flow rate, for example increasing the flow rate to correspond to the flow rate of the first stream. Alternatively, the flow rate of the second air stream through the inlet can be maintained at the reduced flow rate, provided that it is sufficient to transport the evaporated aerosol to one or more sampling ports.

[0076] At step 412, the evaporated aerosol can be sampled via one or more sampling ports for analysis, and the analysis device can be operable to analyze the evaporated aerosol to detect the target substance. As described herein, the time of aerosol sampling can vary relative to the time of heating and providing the second stream so as to sample the evaporated aerosol drawn past the heater after being heated to a certain temperature, or to sample the aerosol evaporated during the step of increasing the power of the heater while reducing the stream. In some cases, the analysis of the evaporated aerosol can be different from the analysis of the vapor sampled in step 404. For example, the detection parameters (such as detection window and threshold) of the analysis device can be independently selected for the vapor sampled in step 404 and the evaporated aerosol sampled in step 412. In this way, the analysis can be optimized to detect the target substance expected to be in the form of vapor or aerosol in the ambient atmosphere.

[0077] It will be understood that the detector inlet device and its components referred to in connection with this method can include, for example, as Figure 1 and 2The device 100 shown in [description], and the method may include controlling the device 100 as previously described herein. For example, the method may include operating the device 100 having a controller 104 as described herein. For example, the method may be implemented by the controller 104 according to instructions (e.g., software) stored in the memory of the controller 104. In some examples, these methods may be performed by fixed control logic configured to control the device. Thus, the methods described herein may be implemented in a computer program or in hardware or in any combination thereof. A computer program includes software, middleware, firmware, and any combination thereof. Such a program may be provided as a signal or a network message and may be recorded on a computer-readable medium, such as a tangible computer-readable medium that can store the computer program in a non-transitory form. Hardware includes computers, handheld devices, programmable processors, general-purpose processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and logic gate arrays.

[0078] Although embodiments of the present disclosure have been described as having particular applications in ion mobility spectrometers, the described devices and methods may be applied to other analytical systems that require testing of vapors such as those associated with aerosols having low vapor pressures.

[0079] As will be understood, a vapor may include a substance that is in its gaseous phase at a temperature below its critical point. An aerosol, in contrast to a vapor or a gas, includes fine particles of a solid or a liquid suspended in a gas. As used herein, the term "evaporation" is used to refer to the conversion of at least some substance from a solid or a liquid into a vapor or a gas.

[0080] Generally speaking, the device features described herein may be provided as method features and vice versa.

[0081] It should also be understood that the specific combinations of the various features described and defined in any aspect of the present invention may be implemented and / or provided and / or used independently. In the context of the present disclosure, other examples and variations will be apparent to those skilled in the art.

Claims

1. An inlet device for a detection system, the device comprising: An inlet for receiving an air stream to be tested, the inlet including a heater configured to heat the air stream to evaporate aerosols carried by the air for sampling by the analysis device; A flow provider configured to draw the air stream through the inlet past the heater for sampling by the analysis device; And A controller configured to control the operation of the heater and the flow provider such that, before increasing the power of the heater to evaporate the aerosol, the flow rate of the air passing through the heater is decreased to reduce cooling of the heater, and the controller is further configured to control the flow provider to provide the aerosol evaporated by the heater for sampling by the analysis device.

2. The device according to claim 1, wherein, The controller is configured to operate the device to detect vapors and aerosols by drawing a first air stream into the inlet with the heater off and providing the first air stream for sampling by the analysis device before decreasing the flow rate of the air passing through the heater.

3. The device according to any one of the preceding claims, wherein, After increasing the power of the heater and decreasing the flow rate, the controller is configured to control the device to draw a second air stream into the inlet past the heater to evaporate the aerosol in the second air stream and thereby provide the evaporated aerosol for sampling by the analysis device.

4. The device according to any one of the preceding claims, wherein, Providing the evaporated aerosol for sampling by the analysis device includes operating the flow provider to increase the flow rate through the inlet.

5. The device according to any one of claims 1 to 3, wherein Decreasing the flow rate of the air passing through the heater includes providing a decreased flow rate, and providing the evaporated aerosol for sampling by the analysis device includes maintaining the decreased flow rate so as to convey the evaporated aerosol from the heater to the analysis device.

6. The apparatus according to any one of claims 1 to 4, wherein Decreasing the flow rate of the air passing through the heater includes causing the flow provider to stop providing flow through the inlet.

7. The apparatus according to any one of the preceding claims, wherein, The controller is configured to: after the heater reaches a threshold temperature and / or after a fixed time delay after the heater is turned on, operate the flow provider to provide the evaporated aerosol to the analysis device.

8. The device according to any one of the preceding claims, wherein, The flow rate through the inlet past the heater before decreasing the flow rate is at least 0.4 m / s, and / or wherein When the heater is on, the flow rate through the inlet past the heater is less than 0.4 m / s, for example wherein, before decreasing the flow rate, the flow rate through the inlet past the heater is at least 0.6 m / s, and / or wherein, when the heater is on, the flow rate through the inlet past the heater is less than 0.3 m / s.

9. The apparatus according to any one of the preceding claims, wherein, The heater includes a heating wire disposed in the path of the air stream in the inlet such that the air stream must pass over the heating wire to reach the analysis device.

10. The device according to any one of the preceding claims, wherein, The heater is configured to heat the air stream to a temperature of at least 150°C to evaporate the aerosol, such as at least 200°C, and / or wherein the heater is configured to heat the air stream to a temperature not exceeding 300°C, such as not exceeding 250°C.

11. The apparatus according to any one of the preceding claims, wherein, The inlet includes one or more sampling ports, and the analysis device is configured to obtain a sample from the inlet through the one or more sampling ports, such as one or more sampling ports selected from a pinhole inlet, a capillary inlet, or a membrane inlet.

12. The apparatus according to claim 11, wherein, The device is configured to provide an air stream through the inlet past the heater and then past the one or more sampling ports.

13. The device according to claim 12, wherein, The flow provider is configured to draw the stream to be sampled past the one or more sampling ports of the analysis device to allow sampling of the vapor in the stream, while drawing particulate matter present in the stream past the one or more sampling ports without entering the one or more sampling ports.

14. A detector, comprising: The inlet device and the analysis device according to any one of the preceding claims, wherein the analysis device is configured to obtain a sample from the inlet to detect a target substance.

15. The detector according to claim 14, wherein, The controller is configured to synchronize the operation of the analysis device with the operation of the flow provider and / or the heater to obtain a sample of the evaporated aerosol provided from the heater to the analysis device through the flow provider.

16. The detector according to claim 14 or 15, wherein, The detector is a portable detector including a portable power source, such as a handheld detector.

17. The detector according to any one of claims 14 to 16, wherein, The detector is configured to draw the air stream from the surrounding environment where the detector is located.

18. The detector according to any one of claims 14 to 17, wherein, The analysis device includes at least one of the following: an ion mobility spectrometer, a differential mobility spectrometer, a mass spectrometer, a chromatography device, or an optical spectrometer.

19. A method for controlling power consumption in a detection device for analyzing vapors and aerosols, the method comprising the following steps performed sequentially: (i) Drawing a first air stream through the inlet of the device; (ii) Sampling the first air stream to detect a target vapor present in the first air stream; (iii) Reducing the flow rate of the air drawn through the inlet to reduce the cooling of a heater provided in the inlet; (iv) Increasing the power to the heater to bring the heater to a temperature for evaporating the aerosol in the inlet; (v) Drawing a second air stream through the inlet past the heater to transport the evaporated aerosol for sampling; and (vi) Sampling the evaporated aerosol to detect the aerosol present in the second air stream.

20. The method according to claim 19, wherein, The first air stream is drawn through the inlet at a first flow rate, and the second air stream is drawn through the inlet at a second flow rate.

21. The method according to claim 20, wherein, The first flow rate is higher than the second flow rate.

22. The method according to claim 21, wherein, The second flow rate corresponds to the reduced flow rate provided in step (iii).

23. The method according to claim 20 or claim 21, wherein, The second flow rate is higher than the reduced flow rate provided in step (iii), such as wherein the second flow rate substantially corresponds to the first flow rate.

24. The method according to any one of claims 19 to 23, wherein, Sampling the first air stream and the second air stream includes: drawing a sample into one or more sampling ports of an analysis device, such as one or more sampling ports selected from a pinhole inlet, a capillary inlet, or a membrane inlet.

25. The method according to any one of claims 19 to 24, comprising: Heating the second air stream to a temperature of at least 150 °C to evaporate the aerosol, such as at least 200 °C, and / or heating the second air stream to a temperature not exceeding 300 °C, such as not exceeding 250 °C.

26. The method according to any one of claims 19 to 25, wherein The flow rate of the first air stream and / or the second air stream through the heater is at least 0.4 m / s, and the reduced flow rate is less than 0.4 m / s.

27. A computer program product configured to program a controller of a detection device to perform the method according to any one of claims 19 to 26, or a fixed logic circuit configured to control a detection device to perform the method according to any one of claims 19 to 26.

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