Patent Description:
The present invention relates generally to a gas analysis network and in particular, but not exclusively, to a real-time on-site gas analysis network for ambient air monitoring and active control and response.

<FIG> illustrate examples of an apparatus and method for real-time gas analysis. <FIG> shows a method using multiple gas-chromatography/mass-spectrometer (GC/MS) systems. Conventional GC/MS systems cannot be installed on-site for direct gas analysis, meaning that special gas sampling pipes are used to provide air inlets at regions of interest, such as regions <NUM>-<NUM>. Each gas sampling pipe carries gas sampled from its respective region to a corresponding GC/MS system that remains in a central lab. Although GC/MS systems can provide excellent detection sensitivity and specificity on multiple gases analysis, such a setup can be quite expensive to maintain.

<FIG> illustrates an alternative method that can be used to reduce cost. Simple portable single-gas detectors are used at specific regions, such as regions <NUM>-<NUM>, for direct gas detection. The detected gas concentrations are then collected and stored at a data center. In some examples the single-gas detectors are incapable of detecting multiple gases separately, and might also constantly suffer from cross-interference of other gases in the field. These and other characteristic make the illustrated arrangement unsuitable for obtaining reliable gas concentration information for active ambient air monitoring and control.

The international patent application publication <CIT> discloses systems for perimeter air quality monitoring that can establish background levels of target contaminants in ambient air prior to initiation of remedial activities. The systems can develop remedial action levels that are protective of the public health for dust and vapors at the remediation property, and can monitor and document fence line ambient air levels of target contaminants during remedial activities. Accordingly the systems and process allow for evaluation of the need for dust or vapor control measures to reduce airborne containment levels to below levels of concern.

The international patent application publication <CIT> describes an apparatus including a substrate and a gas chromatograph having a fluid inlet and a fluid outlet and being mounted to the substrate. A detector array having a fluid inlet and a fluid outlet is mounted to the substrate, and the fluid inlet of the detector array is fluidly coupled to the fluid outlet of the gas chromatograph. A control circuit is coupled to the gas chromatograph and to the detector array such that the control circuit can communicate with the gas chromatograph and to the detector array, and a readout circuit is coupled to the detector array and to the control circuit such that the readout circuit can communicate with the control circuit and the detector array.

The international patent application publication <CIT> discloses a gas detector system comprising a controller and one or more remote gas sensors. The controller may be a standard personal computer running software for detecting the operational status of the gas sensors and signaling an alarm if the gas sensors indicate an alarm condition. The gas sensors may be connected to the controller by way of a universal serial bus. This architecture provides a gas detection system which can be very flexible and full-featured and yet inexpensive. The gas detectors may include detachable portable units which may be removed from their permanent locations to pinpoint the source of a gas leak or to provide routine monitoring of gas levels. The remote units may include data logging functions so that measurements of gas levels at various locations and times can be stored in the portable units for later transmission back to the controller.

In the <CIT>, a detection and control system based on ambient air quality is described. The system sequentially monitors the ambient air quality in different locations of a building or the like, and controls other gases such as carbon dioxide present in the building. The system has at least one sampling head, with a pump associated with that head, a calibration pump, and a selector for selecting operation time of each pump in sequence, and time lapse between sequences. An analyzer analyzes samples of gas from each sampling head and the calibration pump, wherein the analyzer produces an analysis signal representing quantity of contaminant gas present in each sample. This document further discloses that if the level of contaminant gas at the next sampling from the same sampling position is at the same level as a third level or higher, then the LED flashes. If the contaminant gas level is lower, but still above the third level, the LED stays on, but does not flash. However, it is not disclosed in this document how to actively and efficiently reduce contaminant concentration, so as to prevent catastrophic events due to increase of contaminant gases.

Embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

In accordance with the present invention as defined by the independent claims, embodiments thereof are described of a system and method for a real-time on-site gas analysis network for ambient air monitoring and active control and response. Specific details are described to provide a thorough understanding of the embodiments, but one skilled in the relevant art will recognize that the invention can be practiced without one or more of the described details, or with other methods, components, materials, etc. In some instances, well-known structures, materials, or operations are not shown or described in detail but are nonetheless encompassed within the scope of the invention.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a described feature, structure, or characteristic can be included in at least one described embodiment, so that appearances of "in one embodiment" or "in an embodiment" do not necessarily all refer to the same embodiment.

Embodiments are disclosed below of real-time monitoring and control of ambient air quality by using a network of on-site multiple-gas analysis devices in combination with optional anemometers. The embodiments can be applied to various indoor or outdoor environmental setups. In a semiconductor facility, for instance, the embodiments can be used to ensure the cleanroom air is free of airborne molecular contamination (AMC), which becomes critical as semiconductor processing technology goes below <NUM> nodes because AMC affects device yield. In a steel manufacturing facility, the embodiments can be used to monitor coke oven gas by-product leakage and process optimization. In a petrochemical facility, the embodiments can be used to identify leaking gases and locate the source of leakage, which can provide immediate warning and emergency response actions.

<FIG> illustrates an embodiment of an environmental monitoring and control system <NUM> for indoor applications such as semiconductor fabrication facilities, public buildings, etc. A system of multiple gas analysis devices and anemometers are positioned at various indoor locations to form a real-time gas analysis network to monitor the gas concentration and air flow or wind speed and its direction. The gas analysis devices, and anemometers if present, are linked to control/server/information center for real-time data communication and control.

In system <NUM>, one or more multiple-gas analysis devices (also called multiple-gas detectors, or MGDs) are installed at locations within an enclosed facility <NUM>, such as a building, to detect gases of interest for the specific application of the building. Although described herein as a building, in other embodiments facility <NUM> can be a subset of a building, for example a room or enclosed space within a building, and in still other embodiments can include multiple buildings. Building <NUM> can have multiple floors, such as a first floor <NUM> and a second floor <NUM>, and each floor can have some kind of process equipment or process facility: in the illustrated embodiment, first floor <NUM> has a process facility <NUM> and second floor <NUM> has a process facility <NUM>. In other embodiments, of course, there can be more or less floors than shown, every floor need not include a process facility, each floor can have more or less process facilities than shown, and the process facilities can be positioned differently than shown.

In the illustrated embodiment, MGDs are positioned on different floors of the building, with MGDs <NUM>-<NUM> on first floor <NUM> and MGDs <NUM>-<NUM> on second floor <NUM>. On each floor where they are located, the MGDs can be vertically positioned anywhere from floor to ceiling, and all MGDs on a given floor can have, but need not have, the same vertical positioning. An MGD such as MGD6 can be positioned on the exterior of building <NUM>, for example near a vent <NUM>. If MGDs in the interior (MGD1-MGD5) detect contamination inside the facility, exterior MGD6 can help assess whether any contaminants are escaping or entering the facility.

Multiple-gas detectors MGD1-MGD6 are capable of detecting organic or non-organic gas compounds, as well as combination of gases of interest for on-site monitoring (organic or non-organic gas compounds). In one embodiment, one or more of the MGDs can be a miniaturized gas analysis system utilizing a combination of micro-pre-concentrator (micro-PC), micro-gas-chromatography (micro-GC), and a detector array for multiple-gas detection, as described below in connection with <FIG>.

One or more anemometers can optionally be installed in building <NUM> to obtain information about the air flow rate, speed, and direction within the building, as well as other characteristics of the air such as temperature, humidity, and pressure. In the illustrated embodiment each MGD is paired with an anemometer and there is a one-to-one correspondence between MGDs and anemometers (i.e., each MGD has a corresponding anemometer). For example MGD1 is paired with anemometer A1, MGD2 is paired with anemometer A2, and so on. But in other embodiments of system <NUM> the correspondence between multiple-gas detectors and anemometers can be many-to-one instead of one-to-one. The many-to-one correspondence can go both ways: in some embodiments each multiple-gas detector can be paired with a plurality of anemometers, but in other embodiments each anemometer can be paired with a plurality of multiple-gas detectors.

In the illustrated embodiment every MGD has a nearby anemometer, such that each anemometer measures air speed, direction, etc., in the immediate vicinity of its corresponding MGD. But in other embodiments this need not be the case: the anemometers, if present, can be positioned apart from MGD's so that they measure speed, direction, etc., at places in the building other than in the immediate vicinity of an MGD.

Multiple-gas detectors MGD1-MGD6, and anemometers A1-A6 if present, are communicatively coupled to a data/control center via wired or wireless communication. All the MGDs, and anemometers if present, need not be communicatively coupled to the data/control center the same way; some can be communicatively coupled by wire, others wirelessly. By communicatively coupling the MGDs and anemometers to the data center, the instruments can provide the data and control center with the real-time data and updates.

One or more servers in the data and control center collect and analyze readings from the MGDs and anemometers to determine real-time on-site gas concentration at different locations within the facility. The data and control center can provide information analysis, data storage, and corresponding terminal systems feedback and control. The control center analyzes the gas concentration data from MGDs together with the air flow, wind speed, etc., and surrounding obstacles (or topography) and derives a real-time gas concentration distribution map of the whole area of interest. The data center can determine whether there is an abnormal increase of contaminants or gas leakage and can trigger immediate warnings and further identify the location of a specific machine or pipe, for example, that might be causing the change of air quality.

In addition to being communicatively coupled to the MGD's and anemometers if present, the data and control center can be communicatively coupled, by wire or wireless link, to process facilities <NUM> and <NUM> within building <NUM>, or to specific components within a process facility. The data and control center can additionally be communicatively coupled to the building's ventilation system, and to an emergency response team.

If communicatively coupled to process facilities <NUM> and <NUM> within building <NUM>, or to elements within the process facilities, the data and control center can determine the process facility or machine from which gas leakage is occurring and turn off the system to reduce or cease leakage. For example, the control center can be linked and can remotely adjust the facility or system that is determined to be out of spec back to its optimum condition to produce best process yield. The data and control center controls the ventilation system or specific elements within a ventilation system such as pumps, fans, individual vents, duct closures, etc., to immediately reduce the contaminant concentration and prevent any catastrophic events or consequences that could occur due the increase of contaminant gases.

If linked to an emergency response system, the data and control center can provide immediate warning and corresponding action upon detecting contaminants. The data and control center can then notify a response team and direct it to the site of contamination source. The response team can send personnel to the site of abnormal gas outbreak for further test and confirmation, which can then be fed back to control center for close-loop data analysis validation and improvement.

<FIG> illustrates another embodiment of an environmental monitoring and control system <NUM> for indoor applications. System <NUM> is in most respects similar in features and function to system <NUM>. The primary difference between systems <NUM> and <NUM> is that in system <NUM> each MGD is located at or near the output of different air filters, which can be used to filter incoming air from outside the building or outgoing air that exits the building. In one example the filters are part of the air quality/ventilation system of building <NUM>, but in other examples the filters can be part of another system, whether related to the building or not. In system <NUM> each filter is positioned above an MGD, but in other examples the filters need not be positioned above, but can instead be positioned below or to the side of the MGD. An MGD such as MGD6 can be positioned on the exterior of building <NUM>, for example near exiting building through vent <NUM>. A filter F6 can be positioned over vent <NUM> to filter air exiting building <NUM>, and MGD6 can help assess whether any contaminants are escaping the facility and, as a result, whether filter F6 needs replacement. An MGD such as MGD5 can be positioned at the interior of building <NUM>, for example at or near a location where air enters building <NUM> through an air inlet from the ventilation control system. Filter F5 can be positioned to filter contaminants from outside air entering building <NUM>, and MGD5 can help assess whether any contaminants are entering the facility and, as a result, whether filter F5 needs replacement.

In the illustrated embodiment every MGD is coupled to a corresponding air filter, meaning that there is a one-to-one correspondence between MGDs and filters: MGD1 is coupled to filter F1, MGD2 is coupled to filter F2, and so on. But in other embodiments the correspondence can be many-to-one instead of one-to-one: there can be more than one MGD per filter, or more than one filter per MGD. As in system <NUM>, in system <NUM> the MGDs can optionally be paired with anemometers, with a one-to-one correspondence as shown or with a many-to-one correspondence of MGDs to anemometers or anemometers to MGDs.

In system <NUM>, each MGD can monitor the output quality of air passing through the corresponding filter. When the concentration of contaminants (e.g., volatile organic compounds, or VOCs) is beyond the threshold on any MGD, at least one will be able to determine the specific filter that is no longer filtering satisfactorily and needs to be replaced. This approach will greatly reduce unneeded filter replacement and thus minimize the cost of replacement.

<FIG> illustrates an environmental monitoring and control system <NUM> for indoor applications. System <NUM> is in most respects similar in features and function to system <NUM>. The primary difference between systems <NUM> and <NUM> is that in system <NUM> each MGD includes multiple sampling tubes that extended to different locations of MGD's individual region. For instance, MGD <NUM> includes a plurality of sampling tubes <NUM> having one end coupled to MGD4 and its other end, the sampling end through which air is drawn, extending away from MGD4. In the illustrated embodiment of system <NUM> each MGD is coupled to six sampling tubes, but in other embodiments each MGD can be coupled to more or less sampling tubes, and every MGD need not have the same number of sampling tubes.

Each sampling tube <NUM> can also include a VOC or gas sampler, such as sorbent trap <NUM>, through which air collected by the sampling tube can flow. This approach allows one to sample the air at more specific locations with higher spatial coverage density. The sample collection and analysis can be multiple modes. In MGD4, every sampling tube <NUM> includes a sorbent trap, but in other examples less than all tubes can include sorbent traps, or no tubes at all can include sorbent traps. Moreover, every MGD need not include sorbent traps and, if an MGD does include them, need not include the same number of sorbent traps as other MGDs.

Without sorbent traps <NUM>, the air sampling can be done by collecting air from all tubes simultaneously and analyzed by the MGD, which will provide the overall contaminant concentration of the area covered by one MGD. In another mode, the air sampling and analysis can be done in series for each sampling tube (e.g., sample tube #<NUM> and analyze to determine contaminant concentration at sampling tube #<NUM>'s location, and repeat for other sampling tubes), which will provide the more detail contaminant concentration at each specific location. For embodiments with sorbent traps <NUM>, the air sampling can be done simultaneously with the contaminants are separately collected by each sorbent trap. The contaminants in each sorbent trap can then be desorbed to the MGD for analysis in sequence for separate analysis.

<FIG> illustrates an outdoor monitoring and control system <NUM> that can be useful for applications such as petrochemical plants and steel coke ovens. System <NUM> is in most respects similar to system <NUM>: multiple gas analysis devices and anemometers are positioned at various locations to form a real-time gas analysis network to monitor the gas concentration and air flow or wind speed and its direction. The gas analysis devices and/or anemometers are linked to control/sever/information center for real-time data communication and control.

In system <NUM>, one or more multiple-gas analysis devices (also called multiple-gas detectors, or MGDs) are installed at locations within a region of interest <NUM> surrounding an outdoor facility such as a petrochemical plant. Process facilities <NUM>-<NUM> are positioned within region of interest <NUM>. In other embodiments, of course, there can be more or less process facilities than shown, and the process facilities can be positioned differently than shown.

In the illustrated embodiment, MGDs are positioned near process facilities within a relevant area or region of interest <NUM>, with MGDs <NUM>-<NUM> near process facilities <NUM>-<NUM>. Wherever they are located, the MGDs can be vertically positioned anywhere from the floor to some height above the process facility, and all MGDs in a given region <NUM> can have, but need not have, the same vertical positioning. An MGD such as MGD6 can be positioned outside region of interest <NUM>. If MGDs inside region of interest <NUM> (MGD1-MGD5) detect contamination inside the region of interest, exterior MGD6 can help assess whether any contaminants are drifting out of the region of interest. The MGDs used in system <NUM> can have the same characteristics and capabilities as the MGDs used in system <NUM>.

One or more anemometers can optionally be installed in relevant area <NUM> to obtain information about the air flow rate, speed, and direction within the area, as well as other characteristics of the air such as temperature, humidity, and pressure. In the illustrated embodiment each MGD is paired with an anemometer and there is a one-to-one correspondence between MGDs and anemometers (i.e., each MGD has a corresponding anemometer). For example MGD1 is paired with anemometer A1, MGD2 is paired with anemometer A2, and so on. But in other embodiments of system <NUM> the correspondence between multiple-gas detectors and anemometers can be many-to-one instead of one-to-one. The many-to-one correspondence can go both ways: in some embodiments each MGD can be paired with a plurality of anemometers, but in other embodiments each anemometer can be paired with a plurality MGDs.

In the illustrated embodiment every MGD has a nearby anemometer, such that each anemometer measures air speed, direction, etc., in the immediate vicinity of its corresponding MGD. But in other embodiments this need not be the case: the anemometers, if present, can be positioned apart from MGD's so that they measure speed, direction, etc., at places other than in the immediate vicinity of an MGD.

As in system <NUM>, one or more servers in the data and control center collect and analyze readings from the MGDs and anemometers to determine real-time on-site gas concentration at different locations within the region of interest and provide information analysis, data storage, and corresponding terminal systems feedback and control. The control center analyzes the gas concentration data from distributed devices in the network together with the air flow or wind speed, and surrounding obstacles (or topography) and derives a real-time gas concentration distribution map of the whole area of interest. The data center can determine whether there is an abnormal increase of contaminants or gas leakage and can trigger immediate warnings and further identify the location of a machine or pipe, for example, that might be causing the change of air quality. The control center can determine the ambient air quality and also identify the location of gas leakage and whether it is within the area of concern, which in turn prevents false alarms.

In addition to being communicatively coupled to the MGD's and anemometers if present, the data and control center can be communicatively coupled, by wire or wireless link, to process facilities <NUM>-<NUM> within area <NUM>, and can additionally be communicatively coupled to an emergency response team. As in system <NUM>, in system <NUM> the control center can also be communicatively coupled process facilities <NUM> and <NUM> within building <NUM>, or to elements within the process facility, from which gas leakage is occurring and turn off the system to reduce or cease leakage. For example, the control center can be linked and can (remotely) adjust the facility or system that is determined out of spec back to its optimum condition to produce best process yield.

The control center can be linked with emergency response system and provide immediate warning and corresponding action. The data and control center can then notify a response team and direct it to the site of contamination source. The corresponding action team can send personnel to the site of abnormal gas outbreak for further test and confirmation, which can then be fed back to control center for close-loop data analysis validation and improvement.

With the real-time on-site gas concentration at different locations of the manufacturing plants or locations of interest, the data center can continuously determine a synchronized gas distribution based on wind information and buildings/obstacles or surrounding topography and determine whether there is any abnormal increase of specific gases or hazardous gas leakage. For an abnormal increase of a specific gas, which may correspond to decrease of production efficiency as identified by data center, the control center can directly control the specific facility operation to ensure the system is back at optimum condition. For an abnormal increase of specific gas, which may correspond to a hazardous gas leakage, the control center can identify the location or source of gas leakage based on the gas concentration distribution data map and then provide necessary warning and direct a response team to the site of problem.

<FIG> illustrates an environmental monitoring and control system <NUM> for outdoor applications. System <NUM> is in most respects similar in features and function to system <NUM>. The primary difference between systems <NUM> and <NUM> is that in system <NUM> each MGD includes multiple sampling tubes that can extend into or near the process facility with which the MGD is associated. For instance, MGD2 includes a plurality of sampling tubes <NUM> having one end coupled to MGD2 and its other end, the sampling end through which air is drawn, extending into or near process facility <NUM>. In the illustrated embodiment of system <NUM>, MGD2 is coupled to three sampling tubes, but each MGD can be coupled to more or less sampling tubes, and every MGD in system <NUM> need not have the same number of sampling tubes.

Each sampling tube <NUM> can also include a VOC sampler, such as sorbent trap <NUM>, through with air collected by the sampling tube can flow. This approach allows one to sample the air at more specific locations with higher spatial coverage density. The sample collection and analysis can be multiple modes. In MGD4, every sampling tube <NUM> includes a sorbent trap, but in other examples less than all tubes can include sorbent traps, or no tubes at all can include sorbent traps. Moreover, every MGD need not include sorbent traps and, if an MGD does include them, need not include the same number of sorbent traps as other MGDs.

Without sorbent traps <NUM>, the air sampling can be done by collecting air from all tubes simultaneously and analyzing them with the MGD; this will provide the overall contaminant concentration of the area covered by one MGD. In another mode, the air sampling and analysis can be done in series for each sampling tube (e.g., sample tube #<NUM> and analyze to determine contaminant concentration at sampling tube #<NUM>'s location, and repeat for other sampling tubes), which will provide the more detail contaminant concentration at each specific location. For embodiments with sorbent traps <NUM>, the air sampling can be done simultaneously with the contaminants are separately collected by each sorbent trap. The contaminants in each sorbent trap can then be desorbed to the MGD for analysis in sequence for separate analysis.

<FIG> illustrates an embodiment of a process <NUM> for setting up and operating a gas analysis systems such as systems <NUM> and <NUM>. Such a setup can be applied to the following industries (but not limited by those industries) for targeted ambient air monitoring and control in order to achieve optimum manufacturing efficiency and yield output as well as excess waste by-product exhaust or toxic gas leak warning: semiconductor manufacturing fab, display manufacturing, PCB fab, steel coke oven plants, and petrochemical plants.

The process starts at block <NUM>. At block <NUM>, the region of interest, whether indoor or outdoor, is identified. At block <NUM>, the process conducts analysis on space and geographic distribution info for the area of interest on possible gas contaminants or gases of concern, as well as topographical information on obstructions and other objects within the region of interest.

At block <NUM>, based on the analysis performed at block <NUM> the process makes a decision on optimum multiple-gas detector detection specification, number of devices, and placement locations and construction of gas sensing network. At block <NUM>, which is optional as indicated by the dashed outline, the process uses the analysis performed at block <NUM> to decide the number and placement of anemometers within the relevant area.

Operation of the monitoring system begins at block <NUM>, with automatic real-time monitoring data collection and storage at control center. At block <NUM>, automatic data analysis on the reliability of gas monitoring data from each device is performed to ensure no false data due to device or data communication glitches. At block <NUM>, the process searches for source location of abnormal gas concentration level based on analysis of gases data (in combination with air flow, wind speed, direction, etc., and area topography if anemometers are used). At block <NUM>, the process determines whether the source location has gases concentration over threshold level, and at block <NUM> the available data from all MGD's, and anemometers if present, is used to identify the contamination source. At block <NUM>, the process takes action such as controlling the ventilation system and/or process facilities for an indoor application, controlling the process facilities for an outdoor application, and provide necessary warning to corresponding party for necessary action in either indoor or outdoor applications. For situation that there are many possible sources of gas leakage systems and same location without an individual gas device to differentiate the gas leakage on-site, personnel may be sent to perform an on-site test on each system with a portable gas detector to confirm the actual problematic system.

<FIG> schematically illustrate an embodiment of a multiple-gas detection and analysis device that can be implemented in the above-described environmental detection and control systems. A commercial embodiment of the illustrated multiple-gas analysis device, known as MiTAP, is developed by TricornTech Taiwan & TricornTech Corporation of San Jose, California. MiTAP can provide more frequent gas concentration distributions for data analysis, which in turn gives the control center much faster update of ambient air condition at corresponding field site. As a result, a more precise active control of air quality can be achieved for consistent robust manufacturing yield, which can be extremely crucial in manufacturing processes such as semiconductor production. Meanwhile, for toxic gas leakage monitoring, MiTAP can provide much faster update/warning on the event of gas leakage, which can be crucial to prevent life-threatening system failures at the manufacturing site.

As further described below, MiTAP utilizes micro-pre-concentration (micro-PC), micro-gas-chromatography (micro-GC), and detector array (DA) technology for direct air sampling and gas analysis as described, for example, in<CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

It is a portable and stand-along device that does not require expensive laboratory gas supplies and piping setups, but unlike conventional GC/MS systems, it can be installed on-site and is able to perform direct gas sampling for multiple-gas analysis with performance similar to GC/MS system in the laboratory. The device has capability to separate and detect more than <NUM> volatile organic compounds (VOCs) in each <NUM>-min test (but not limited to VOCs), which can provide much more real-time data points for faster active control and response compared to conventional GC/MS system method for gas analysis.

<FIG> together illustrate an embodiment of a small-scale multiple-gas analysis device <NUM>. MGD <NUM> includes a substrate <NUM> on which are mounted a fluid handling assembly <NUM>, a controller <NUM> coupled to the individual elements within fluid handling assembly <NUM>, and a reading and analysis circuit <NUM> coupled to detector array <NUM> and to controller <NUM>. The embodiment shown in the figures illustrates one possible arrangement of the elements on substrate <NUM>, but in other embodiments the elements can, of course, be arranged on the substrate differently.

Substrate <NUM> can be any kind of substrate that provides the required physical support and communication connections for the elements of device <NUM>, such as a single-layer or multi-layer printed circuit board (PCB) with conductive traces or a chip or wafer made of silicon or some other semiconductor. In still other embodiments, substrate <NUM> can also be a chip or wafer in which optical waveguides can be formed to support optical communication between the components of device <NUM>.

Fluid handling assembly <NUM> includes a filter and valve assembly <NUM>, a pre-concentrator <NUM>, a gas chromatograph <NUM>, a detector array <NUM> and a pump <NUM>. Elements <NUM>-<NUM> are fluidly coupled in series: filter and valve assembly <NUM> is fluidly coupled to pre-concentrator <NUM> by fluid connection <NUM>, pre-concentrator <NUM> is fluidly coupled to gas chromatograph <NUM> by fluid connection <NUM>, gas chromatograph <NUM> is fluidly coupled to detector array <NUM> by fluid connection <NUM>, and detector array <NUM> is coupled to pump <NUM> by fluid connection <NUM>. In one embodiment of device <NUM> elements <NUM>-<NUM> can be micro-electromechanical (MEMS) elements or MEMS-based elements, meaning that some parts of each device can be MEMS and other parts not. In other embodiments of device <NUM>, some or all of elements <NUM>-<NUM> need not be MEMS or MEMS-based, but can instead be some non-MEMS chip scale device.

As indicated by the arrows in the figures, the fluid connections between elements <NUM>-<NUM> allow a fluid (e.g., one or more gases) to enter filter and valve assembly <NUM> through inlet <NUM>, flow though elements <NUM>-<NUM>, and finally exit pump <NUM> through outlet <NUM>. Fluid handling assembly <NUM> also includes a shroud or cover <NUM> that protects individual elements <NUM>-<NUM>. In the illustrated embodiment, channels formed in shroud <NUM> provide the fluid connections between the elements, but in other embodiments the fluid connections between elements can be provided by other means, such as tubing. In still other embodiments shroud <NUM> can be omitted.

Controller <NUM> is communicatively coupled to the individual elements within fluid handling assembly <NUM> via traces <NUM> such that it can send control signals and/or receive feedback signals from the individual elements. In one embodiment, controller <NUM> can be an application-specific integrated circuit (ASIC) designed specifically for the task, for example a CMOS controller including processing, volatile and/or non-volatile storage, memory and communication circuits, as well as associated logic to control the various circuits and communicate externally to the elements of fluid handling assembly <NUM>. In other embodiments, however, controller <NUM> can instead be a general-purpose microprocessor in which the control functions are implemented in software. In the illustrated embodiment controller <NUM> is electrically coupled to the individual elements within fluid handling assembly <NUM> by conductive traces <NUM> on the surface or in the interior of substrate <NUM>, but in other embodiments controller <NUM> can be coupled to the elements by other means, such as optical.

Readout and analysis circuit <NUM> is coupled via traces <NUM> to an output of detector array <NUM> such that it can receive data signals from individual sensors within detector array <NUM> and process and analyze these data signals. In one embodiment, readout and analysis circuit <NUM> can be an application-specific integrated circuit (ASIC) designed specifically for the task, such as a CMOS controller including processing, volatile and/or non-volatile storage, memory and communication circuits, as well as associated logic to control the various circuits and communicate externally. In other embodiments, however, readout and analysis circuit <NUM> can instead be a general-purpose microprocessor in which the control functions are implemented in software. In some embodiments readout and analysis circuit <NUM> can also include signal conditioning and processing elements such as amplifiers, filters, analog-to-digital converters, etc., for both pre-processing of data signals received from detector array <NUM> and post-processing of data generated or extracted from the received data by readout and analysis circuit <NUM>.

In operation of device <NUM>, the system is first powered up and any necessary logic (i.e., software instructions) is loaded into controller <NUM> and readout and analysis circuit <NUM> and initialized. After initialization, the valve in filter and valve unit <NUM> is opened and pump <NUM> is set to allow flow through the fluid handling assembly. Fluid is then input to fluid handling assembly <NUM> through inlet <NUM> at a certain flow rate and/or for a certain amount of time; the amount of time needed will usually be determined by the time needed for pre-concentrator <NUM> to generate adequate concentrations of the particular chemicals whose presence and/or concentration are being determined. As fluid is input to the system through inlet <NUM>, it is filtered by filter and valve assembly <NUM> and flows through elements <NUM>-<NUM> within fluid handling assembly <NUM> by virtue of the fluid connections between these elements. After flowing through elements <NUM>-<NUM>, the fluid exits the fluid handling assembly through exhaust <NUM>.

After the needed amount of fluid has been input through inlet <NUM>, the valve in filter and valve assembly <NUM> is closed to prevent further input of fluid. After the valve is closed, a heater in pre-concentrator <NUM> activates to heat the pre-concentrator. The heat releases the chemicals absorbed and concentrated by the pre-concentrator. As the chemicals are released from pre-concentrator <NUM>, pump <NUM> is activated to draw the released chemicals through gas chromatograph <NUM> and detector array <NUM> and output the chemicals through exhaust <NUM>. Activation of pump <NUM> also prevents backflow through fluid handling assembly <NUM>.

As the chemicals released from pre-concentrator <NUM> are drawn by pump <NUM> through gas chromatograph <NUM>, the chromatograph separates different chemicals from each other in the time domain-that is, different chemicals are output from the gas chromatograph at different times. As the different chemicals exit gas chromatograph <NUM> separated in time, each chemical enters detection array <NUM>, where sensors in the detection array detect the presence and/or concentration of each chemical. The time-domain separation performed in gas chromatograph <NUM> substantially enhances the accuracy and sensitivity of detection array <NUM>, since it prevents numerous chemicals from entering the detection array at the same time and thus prevents cross-contamination and potential interference in the sensors within the array.

As individual sensors within detection array <NUM> interact with the entering time-domain-separated chemicals, the detection array senses the interaction and outputs a signal to readout and analysis circuit <NUM>, which can then use the signal to determine presence and/or concentration of the chemicals. When readout and analysis circuit <NUM> has determined the presence and/or concentration of all the chemicals of interest it can use various analysis techniques, such as correlation and pattern matching, to extract some meaning from the particular combination of chemicals present and their concentrations.

<FIG> illustrates an embodiment of a multiple-gas analysis system or detector <NUM>. MGD <NUM> is in most respects similar to device <NUM>. The primary difference between device <NUM> and device <NUM> is the presence in device <NUM> of a wireless transceiver circuit <NUM> and an antenna <NUM> mounted on substrate <NUM>. Wireless transceiver circuit <NUM> can both transmit (Tx) data and receive (Rx) data and is coupled to reading and analysis circuit <NUM> and antenna <NUM>. In one embodiment of MGD <NUM>, transceiver <NUM> can be used to wirelessly transmit data from reading and analysis circuit <NUM> to a computer <NUM>, which can be located in the data and control center of systems <NUM> or <NUM> and can perform the previously-described functions of the data center.

<FIG> illustrates an alternative embodiment of a multiple-gas analysis device <NUM>. MGD <NUM> is in most respects similar to MGD <NUM>. The primary difference between MGDs <NUM> and <NUM> is that the wireless transceiver circuit <NUM> and antenna <NUM> are replaced with a hardware data interface <NUM> coupled to reading and analysis circuit <NUM>. In one embodiment, hardware data interface <NUM> could be a network interface card, but in other embodiments hardware data interface can be an Ethernet card, a simple cable plug, etc. External devices can be connected to device <NUM> through traditional means such as cables. Although it has a different communication interface, MGDs <NUM> and <NUM> have all the same functionality. As with system <NUM>, in system <NUM> gas analysis device <NUM> can transmit data to, and receive data from, one or both of a computer <NUM>, which can be located in the data and control center of systems <NUM> or <NUM> and can perform the previously-described functions of the data center.

<FIG> illustrates an alternative embodiment of a multiple-gas analysis device <NUM>. MGD <NUM> is in most respects similar to device <NUM>. The primary difference between MGD <NUM> and device <NUM> is that MGD <NUM> includes an on-board display <NUM> for conveying to a user the results of the analysis performed by reading and analysis circuit <NUM>. The illustrated embodiment uses an on-board text display <NUM>, for example an LED or LCD screen that can convey text information to a user. In another embodiment a simpler display can be used, such as one with three lights that indicate a positive, negative, or indeterminate result depending on which light is switched on. For example, if in response to detection of contaminants it is necessary to send an inspection team to investigate, the device can provide information to the inspectors.

<FIG> illustrates an alternative embodiment of a multi-gas analysis device <NUM>. MGD <NUM> is in most respects similar to MGD <NUM>. The primary difference between device <NUM> and device <NUM> is that in device <NUM> one or more elements of fluid handling assembly <NUM> are replaceable. In the illustrated embodiment, the elements are made replaceable by mounting them onto substrate <NUM> using sockets: filter and valve assembly <NUM> is mounted to substrate <NUM> by socket <NUM>, pre-concentrator is mounted to substrate <NUM> by socket <NUM>, gas chromatograph <NUM> is mounted to substrate <NUM> by socket <NUM>, detector array <NUM> is mounted to substrate <NUM> by socket <NUM>, and pump <NUM> is mounted to substrate <NUM> by socket <NUM>. In one embodiment, sockets <NUM>-<NUM> are sockets such as zero insertion force (ZIF) sockets that permit easy replacement by a user, but in other embodiments other types of sockets can be used. Although the illustrated embodiment shows all the components of fluid handling assembly <NUM> being replaceable, in other embodiments only some of the components such as pump <NUM> and detector array <NUM> can be made replaceable. The benefit of having replaceable fluid handling elements is that the MGD can be easily repaired if broken or can be easily converted to detect different gases or combinations of gases without the need to replace the entire MGD.

Claim 1:
A system for gas monitoring and control comprising:
a plurality of multiple-gas analysis devices (MGD1-MGD6), each positioned near a process facility (<NUM>, <NUM>) within a region of interest (<NUM>) around the process facility (<NUM>, <NUM>), each multiple-gas analysis device (MGD1-MGD6) capable of detecting the presence, concentration, or both, of one or more gases; and
a data and control center communicatively coupled to each of the plurality of multiple-gas analysis devices (MGD1-MGD6), the data and control center including logic that, when executed, allows the data and control center to:
monitor readings from the plurality of multiple-gas analysis devices (MGD1-MGD6), and
if any readings indicate the presence of one or more contaminants, identifying the source of the contaminants based on the readings from the plurality of multiple-gas analysis devices (MGD1-MGD6);
wherein the region of interest (<NUM>) is indoors or outdoors;
each multiple-gas analysis device (MGD1-MGD6) includes multiple sampling tubes (<NUM>) that are fluidly coupled to and extend from the multiple-gas analysis device (MGD1-MGD6) to a location in or near the associated process facility (<NUM>, <NUM>);
the data and control center is communicatively coupled to a ventilation system configured to reduce the contaminant concentration within the region of interest (<NUM>); and
the data and control center is configured to control operation of the ventilation system.