MODULAR SYSTEM AND APPARATUS FOR TESTING GAS DETECTORS

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to devices, systems and methods for the testing of gas detectors, and especially, to devices, systems and methods for calibrating or testing a response of one or more gas sensors of one or more gas detectors to one or more analyte test gases.

[0002] Gas detectors including one or more gas sensors (for example, electrochemical gas sensors, combustible gas sensors, etc.) are well known for monitoring for potentially hazardous gases in various environments. Generally, gas from the environment to be monitored comes into contact with the sensors(s) within the detector by diffusion or by forced flow. Electronics within the detector convert the output signal from the sensor(s) into one or more signals representative of a gas concentration. The sensor output per unit amount of gas can vary with time and hence periodic calibration is required to ensure that the detector reading is accurate.

[0003] Currently, sensors of gas detectors are calibrated by passing a calibration gas having known, fixed compositions of one or more analyte gases from a compressed gas cylinder into the detector, thereby displacing ambient air within the detector and exposing the sensor(s) to the calibration gas. The calibration gas is allowed to flow until the sensor output reaches a steady state. Since the calibration gas has a known composition, the output signal from each sensor of the gas detector can be adjusted to provide an accurate measure of analyte gas concentration. Excess calibration gas flows out of the detector. In the interval between full calibrations, an intermediate test (sometimes referred to as a bump test) can be performed to ensure that a sensor or instrument is responding to a specific analyte test gas. As used herein, the term "testing" refers generally to all types of analysis of the operation of a gas detector and includes, for example, full calibration and bump testing.

[0004] Safe commercial practice dictates that sensors within a gas detector be tested, including calibrated, at a minimum according to the manufacturer's recommendations. Various calibration/testing systems and methods have been developed to facilitate gas detector testing. Gas detector calibration/testing systems are disclosed, for example, in U.S. Patent Nos. 5,239,492, 4,854,153 and 5,655,894. European patent No. EP 1 342 082 discloses a calibration system for use with a portable gas detector.

[0005] Moreover, several calibration/testing systems are commercially available in the United States. For example, the MICRODOCK™ automatic test and calibration station available from BW Technologies of Canada provides a calibration and bump testing station for the GasAlertMicro™ multi-gas detector. One inlet is provided for ambient air, and another inlet is provided for connection to a single pressurized gas cylinder. As described in the MicroDock Automating Test and Calibration Station User Manual (2103) available from BW Technologies, multiple gas detector docking modules can be connected to the system.. However, test gas can flow to only one connected docking module at a time and thus only one gas detector can be calibrated at any one time. Also, the TIM® Total Instrument Manager calibration/testing system is available from Mine Safety Appliances Company of Pittsburgh, Pennsylvania, which provides, among other functions, full calibration and bump testing for several Mine Safety Appliances Company gas detectors, including multi-gas instruments and single gas monitors.

[0006] Although strides have been made in facilitating testing of gas detectors, a number of problems still persist. Among other problems, currently available calibration systems can require time consuming changes in connections of gas cylinders and gas detectors as well as changes in test conditions to test a single or multiple gas detectors with one or more test gases.

[0007] It thus remains desirable to develop improved (for example, more automated) devices, systems and methods for testing of gas detectors.

SUMMARY OF THE INVENTION

[0008] In one aspect, the present invention provides a testing module for use with a gas detector, including: a housing; a seating connected to the housing and adapted to operably connect the gas detector to the testing module; a plurality of gas inlets connected to the housing, each gas inlet adapted to pass a gas therethrough; and a plurality of gas outlets connected to the housing, each gas outlet being in fluid connection with one of the gas inlets. The plurality of gas outlets are configured on the housing in generally the same configuration as the plurality of inlets are configured on the housing. Further, each of the plurality of outlets is adapted to mate with and form a fluid connection with one of a plurality of inlets of a second like testing module. Once such fluid connections are made, gases can flow from the outlets of the testing module into the inlets of the second like testing module.

[0009] The testing module can further include a communication system to receive information and/or to transmit information. The communication system can be provided to transmit and receive communications between the testing module and the second like testing module when connected. The testing module can also include a data input system and a data output system. The testing module can further include a flow control system adapted to provide flow from at least one of the plurality of inlets to the gas detector.

[0010] In one embodiment, the plurality of inlets are configured in a generally linear configuration. Each of the plurality of inlets can, for example, include a barbed connector.

[0011] In another aspect, the present invention provides a gas container module for use with a gas container, including: a housing; a seating connected to the housing and adapted to receive the gas container; a plurality of gas inlets connected to the housing, each inlet adapted to pass a gas therethrough; and a plurality of gas outlets connected to the housing. Each inlet is in fluid connection with one of the outlets. The plurality of inlets are configured on the housing in generally the same

configuration as the plurality of outlets are configured on the housing. Each of the plurality of inlets is adapted to mate with and form a fluid connection with one of a plurality of outlets on a housing of a second like gas container module. Once such fluid connections are made, gases can flow from the outlets of the second like gas container module into the inlets of the gas container module.

[0012] The gas container module can further include a gas container conduit in fluid connection with one of the outlets at a first end thereof. The gas container conduit is adapted to form a connection with the gas container at a second end thereof. The gas container module can also include a demand regulator in fluid connection with the second end of the gas container conduit.

[0013] In one embodiment there are at least X inlets Ii through I _x and at least X+l outlets Oi though Oχ ₊ i. The first end of the container conduit is in fluid connection with outlet Oi , and each inlet I ₁ is in fluid connection with outlet O _{1+ 1} . In one embodiment, there are at least two inlets Ii and I ₂ and at least three outlets Oi through O ₃ , wherein the first end of the gas container conduit is in fluid connection with outlet Oi, inlet Ii is in fluid connection with O ₂ and inlet I ₂ is in fluid connection with outlet O ₃ . In one embodiment, the outlet Oi is adapted to mate with and form a fluid connection with inlet Ii ' of the second like gas container module and outlet O ₂ is adapted to mate with and form a fluid connection with inlet I ₂ ' of the second like gas container module. The gas container module of can further include a connector to mate with and form a connection with outlet O ₃ . The gas container module can also include an air inlet connected to the housing and being in fluid connection with an air outlet connected to the housing The air inlet is adapted to mate and form a fluid connection with an air inlet of the second like gas container module.

[0014] The gas container module can further include a communication system. In one embodiment, the gas container includes a sensor in communicative connection with the communication system. The sensor is adapted to read data from the gas container.

[0015] In one embodiment, the plurality of inlets are arranged in a series on a first section of the housing of the gas container module and the plurality of outlets are arranged in a series in a second section of the housing of the gas container module. The gas container module can also include a container conduit in fluid connection with one of the outlets at a first end. The container conduit is adapted to form a connection with the gas container at a second end thereof. Each of the plurality of inlets is in fluid connection with one of the plurality of outlets such that when a plurality of like gas container modules are connected in a series, a gas exiting each outlet is determined by a position in the series of gas container modules of the one of the gas container modules seating a corresponding gas container.

[0016] In still a further aspect, the present invention provides a gas detector testing system, including at least one testing module for use with a gas detector as described above and at least one gas container module for use with a gas container as described above. In one embodiment, the testing module includes: a testing module housing; a seating connected to the testing module housing and adapted to operably connect the gas detector to the testing module; a plurality of inlets connected to the testing module housing, each inlet adapted to pass a gas therethrough; and a plurality of outlets connected to the testing module housing, each outlet being in fluid connection with one of the gas inlets. As described above, the plurality of outlets are configured on the testing module housing in generally the same configuration as the plurality of inlets are configured on the testing module housing. Each of the plurality of outlets is adapted to mate with and form a fluid connection with one of a plurality of inlets of a second like testing module. Once such fluid connections are made, gases can flow from the outlets of the testing module into the inlets of the second like testing module.

[0017] In this embodiment, the gas container module, includes: a gas container module housing; a seating connected to the gas container module housing and adapted to receive the gas container; a plurality of gas inlets connected to the gas container module housing, each gas inlet adapted to pass a gas therethrough; and a

plurality of gas outlets connected to the gas container module housing, each gas inlet being in fluid connection with one of the gas outlets. The plurality of gas inlets are configured on the gas container housing in generally the same configuration as the plurality of gas outlets are configured on the gas container housing. Each of the plurality of gas inlets is adapted to mate with and form a fluid connection with one of a plurality of gas outlets on a gas container housing of a second like gas container module. Once such fluid connections are made, gases can flow from the gas outlets of the second like gas container module into the gas inlets of the gas container module.

[0018] The plurality of inlets of the testing module are also configured on the testing module housing in generally the same configuration as the plurality of gas outlets are configured on the gas container module housing. Further, each of the plurality of inlets of the testing module are adapted to mate with and form a fluid connection with one of the gas outlets of the gas container module. Once such fluid connections are made, gases can flow from the gas outlets of the gas container module into the inlets of the testing module.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other aspects of the invention and their advantages will be discerned from the following detailed description when read in connection with the accompanying drawings, in which:

[0020] Figure 1 illustrates a side perspective view of an embodiment of a testing module of the present invention with an embodiment of a battery pack in alignment for connection therewith.

[0021] Figure 2A illustrates a perspective view of the testing module of Figure 1 with the access door thereof in an open state.

[0022] Figure 2B illustrates a perspective view of the testing module of Figure 1 with the access door thereof in an open state with a gas detector placed in operative connection therewith.

[0023] Figure 3A illustrates a side perspective view of the testing module of Figure 1 from the opposite side of Figure 1 and a side view of the battery pack of Figure 1.

[0024] Figure 3B illustrates a side perspective view of the testing module of Figure 1 from the opposite side of Figure 1 with an embodiment of an end cap in alignment for attachment thereto.

[0025] Figure 4 illustrates a schematic diagram of an embodiment of a testing system of the present invention in which three gas container modules of the present invention and two testing modules of the present invention are connected in series.

[0026] Figure 5 A illustrates a front view of the testing system of Figure 4.

[0027] Figure 5B illustrates a side perspective view one of the gas container modules of Figure 5 A.

[0028] Figure 5C illustrates a side perspective view one of the gas container modules of Figure 5 A from the opposite side of Figure 5B.

[0029] Figure 6A illustrates a perspective view of an embodiment of a testing system of the present invention resting on a surface in which two gas container modules and two testing modules are connected in series, and a network communication module is connected to the end or last testing module of the series.

[0030] Figure 6B illustrates a schematic diagram of the testing system of Figure 6A.

[0031] Figure 7A illustrates a front view of a gas container module of the present invention in alignment for connection to a testing module of the present invention.

[0032] Figure 7B illustrates a schematic diagram of a gas container module of the present invention connected to a testing module of the present invention, to which a battery pack is connected.

[0033] Figure 8A illustrates a schematic diagram of gas flow through a gas container module of the present invention.

[0034] Figure 8B illustrates a schematic diagram of gas flow through three gas containers modules of the present invention connected in series.

[0035] Figures 9 illustrates a schematic diagram of a testing module of the present invention showing, among other things, communication paths between connected testing modules, between a testing module and a gas detector in operative connection with the testing module, between a testing module and a connected memory card and between a testing module and a network via a network interface.

[0036] Figure 10 illustrates a gas container module of the present invention in operative connection with a pair of DIN rails for mounting on a vertical surface.

DETAILED DESCRIPTION OF THE INVENTION

[0037] In general, the devices, systems and methods of the present invention are discussed using representative embodiments in which three test gases and air are transported through the system of the present invention for the testing of gas detectors. One skilled in the art appreciates that the devices, systems and methods of the present invention are readily expanded to use more than three test gases and air. Likewise, the devices, systems and methods of the present invention are discussed using representative embodiments of systems in which a single gas container module as described herein is connected to a single testing module as described herein, or in

which two or three gas container modules (connected in series) are connected to one testing module or to two testing modules (connected in series). One skilled in the art appreciates that the devices, systems and methods of the present invention are readily expanded to connect more than three gas container modules of the present invention and more than two testing modules of the present invention.

[0038] Figure 1 illustrates an embodiment of a gas detector testing module 10 of the present invention. Test stand or testing module 10 includes a plurality of inlets on a first side 22 of a housing 20 thereof. In the embodiment of Figure 1 , testing module 10 includes four inlets 30, 40, 50 and 60 arranged generally along a line at predetermined, unique positions (unique vertical positions in the orientation of Figure 1) on housing 20. One skilled in the art will appreciate that virtually any number of inlets in a variety of configurations can be provided in the present invention. In the embodiment of Figure 1, inlets 30, 40, 50 and 60 can, for example, comprise 1/8 inch barbed connectors as known in the gas connection arts. Inlets 30, 40, 50 and 60 are surrounded by a connecting and protecting flange 24, the operation of which is discussed below.

[0039] Testing module 10 further includes data input and output systems. For example, a pass indicator 70 and a fail indicator 72 (for example, LED indicators) are provided to indicate to an operator if a gas detector in operative connection with testing module 10 has passed or failed a particular test. Likewise, a display 74 is provided to display information to an operator. In the embodiment of Figure 1, a menu of commands is provided on display 74 through which an operator can scroll and choose a command or commands using down, up and enter controls 76, 78 and 80, respectively. Housing 10 further includes a hinged access door 26 through which a gas detector 300 can be placed in a seating 29 of testing module 10 for operative connection with testing module 10 (see, for example, Figures 2A and 2B). Housing 20 can further include a latch system 27 as known in the art to maintain access door 26 in a closed state.

[0040] Figure 3A illustrates a second side 28 of housing 20. As illustrated in Figure 3 A, testing module 10 includes four outlets 32, 42, 52 and 62, which can, for example, include cooperating connectors or ports suitable to form a fluid connection with the 1/8 inch barbed connectors (or other connectors) so as to form a generally sealed fluid connection with inlets 30, 40, 50 and 60, respectively, of a second like testing module 10a (see, for example, Figure 5A). Outlets 32, 42, 52, and 62 are surrounded by a connecting flange 24'.

[0041] As illustrated in, for example, Figure 4, first inlet 30 is in fluid connection with first outlet 32 via fluid path or conduit 34, second inlet 40 is in fluid connection with second outlet 42 via fluid path or conduit 44, third inlet 50 is in fluid connection with third outlet 52 via fluid path or conduit 54, and fourth inlet 60 is in fluid connection with fourth outlet 62 via a fluid path or conduit 64. Figure 4 is a representative and somewhat idealized schematic diagram illustrating flow elements, paths and connections of an embodiment of a testing system of the present invention. The relative dimensions and positions of such flow element, paths and connection are not representative of such dimensions and positions as, for example, illustrated in other figures herein.

[0042] Testing module 10 can operate alone or in connection with one or more other testing modules. As illustrated, for example, in Figures 4 and 5A, testing module 10 can be connected to another testing module 10a which includes a like housing 20a. In several embodiments, the exterior housings of the testing modules of the present invention were identical. However, the physical and electrical connections within different housings can be different to operate with different gas detectors. Likewise, the flow path from the test gas flow conduits within the housing to the gas detector to be tested can vary between testing modules. For example, in Figure 4, testing module 10 is designed to operate with a gas detector 300 in which test gas reaches a sensor or sensors within gas detector 300 via forced flow created by a pump (not shown) within gas detector 300. As illustrated in Figure 4, a pressure sensor can be placed in fluid connection with the flow path to the gas detector to

ensure that the gas detector pump is operating correctly. Testing module 10a (for which, the fluid path from conduits 34a, 44a, 54a, and 64a is shown only partially) includes a pump in the flow path to a detector 310 seated therein to ensure the flow of test gas to the detector 310 in which (during field operation) test gas reaches a sensor or sensors within gas detector 300 via diffusion flow. In the embodiment illustrated, for example, in Figure 4, solenoid controlled valves Sl , S2 and S3 of testing module 10 are used in a manner known in the flow control arts to control which gas flows to gas detector 300. Various gas detectors, including, for example, the SOLARIS® Datalogging Multigas Detector, the SIRIUS® Multigas Detector and the ORION® Datalogging Multigas Detector, all available from Mine Safety Appliances Company, have been tested using the systems of the present invention. In such detectors, air can be used as a control or comparison gas during calibration.

[0043] In testing modules 10 and 10a as illustrated in Figure 4, the flow paths within the testing modules between gas flow conduits 34, 44, 54 and 64 and gas detector 300 and between 34a, 44a, 54a and 64a and gas detector 310 include connections to each flow conduit. However, one or more testing modules of the present invention can be provided in which the flow path within the testing module between the test gas flow conduits and the gas detector does not have connections to all the test gas flow conduits.

[0044] As illustrated in Figure 4, each testing module can be provided with a controller. Software for operation of the testing module can, for example, be stored in a memory that is in operative connection with a microprocessor. Data can, for example, be input into a software program of a testing module to, among other things, define which test gas flow conduit includes the appropriate test gas to be used in testing the gas detector that is operably connected to the testing module.

[0045] In general, like components of testing module 10a are numbered similarly to corresponding components of testing module 10 with the addition of the designation "a". When testing module 10 is in operative connection with testing

module 10a, as illustrated, for example, in Figures 4 and 5 A, outlets 32, 42, 52 and 62 of testing module 10 are placed in fluid connection with inlets 30a, 40a, 50a and 60a, respectively, of testing module 10a enabling gas to pass freely from conduits 34, 44, 54 and 64 to conduits 34a, 44a, 54a and 64a, respectively. Should testing module 10a be the last in a series of connected testing modules, flow terminators 36a, 46a, 56a and 66a (for example, rubber caps) can be placed upon outlets 32a, 42a, 52a and 62a, respectively, as illustrated in Figure 4. Alternatively, another testing module (not shown) can be attached to testing module 10a by connecting the inlets of the additional testing module to outlets 32a, 42a, 52a and 62a of testing module 10a. As an alternative to the use of flow terminators, normally closed check valves (not shown) as known in the art can be provided in fluid connection with the outlets of each testing module. In general, the outlet check valves of a first testing module remain closed until inlets of a second like testing module are mated with, and thereby placed in fluid connection with, the outlets of the first testing module.

[0046] Flange 24' of testing module 10 is adapted to connect to flange 24a of testing module 10a. Flanges 24' and 24a can be secured using a connector (for example, a screw which passes through aligned holes 25' and 24a in flanges 24' and 24a, respectively) to secure the connection between testing module 10 and testing module 10a. In addition to providing a secure connection, cooperating flanges 24' and 24a also act to protect connected elements (for example, flow elements such as the inlets and outlets described above, intermodule communication elements and intermodule power elements) encompassed thereby.

[0047] By connecting testing modules of the present invention in series as described above, sensors of multiple gas detectors can be tested (for example, in an automated, simultaneous fashion) using multiple sources of test gas which are attached to the inlets of the first testing module of the series of testing modules. As illustrated, for example, in Figures 4 through 7B, in several embodiments of the present invention, one or more gas container or gas cylinder holding modules 210 are used to deliver test gas and/or air to one or more of the testing modules of the present

invention. As illustrated, for example, in Figure 7A, in one embodiment, gas container module 210 includes a housing 220 supporting four inlet connectors 230, 240, 250 and 260 on a first side 222 thereof. Inlets connectors 230, 240, 250 and 260 can, for example, include 1/8 inch barbed connectors as known in the gas connection arts. As described more fully below, inlet connector 260 does not operate as a gas inlet, but only as a connector when connecting to another like gas container module . Inlet connectors 230, 240, 250 and 260 are referred to generally herein as inlets. Inlets 230, 240, 250 and 260 are positioned in generally the same configuration as inlets 30, 40, 50 and 60 of testing module 10 (as well as in generally the same configuration as the inlets of other like testing modules). Inlet connectors 230, 240, 250 and 260 are surrounded by a connecting flange 224 including connecting elements 225 (for example, screw holes).

[0048] Gas container module 210 also includes four outlet connectors or outlets 232, 242, 252 and 262 on a second side 228 thereof. Outlets 232, 242, 252 and 262 can, for example, include connectors suitable to form a fluid connection with the barbed connectors of inlets 230, 240, 250 and 260 of another gas connector module or with the barbed connectors of inlets 30, 40, 50 and 60 of testing module 10 (or with the inlets of another like testing module of the present invention). Outlets 232, 242, 252 and 262 are positioned in generally the same configuration as outlets 32, 42, 52 and 62 of testing module 10 (as well as in generally the same configuration as the outlets of other like testing modules). Outlets 232, 242, 252 and 262 are surrounded by a connecting flange 224' including connecting elements 225' (for example, screw holes).

[0049] In one embodiment as illustrated in Figures 8A and 8B, inlet 230 is connected to outlet 232 via a fluid path or conduit 234. Outlet 242 is in fluid connection with a conduit 246 (for example, flexible tubing) at a first end of conduit 246. At a second end, conduit 246 is in fluid connection with a demand regulator 248 (see, for example, Figure 3A, 8A and 8B), which is adapted to be connected to a pressurized gas cylinder 400 as known in the art. Housing 220 of gas

container module 210 includes a retainer 226 that can be shaped and dimensioned to securely hold gas cylinder 400 therein. Inlet 240 is connected to outlet 252 via a fluid path or conduit 244. Inlet 250 is connected to outlet 262 via a fluid path or conduit 254. Final inlet 260 includes a cooperating connector as described above, but is not connected to any fluid path or outlet. Once again, bottom or final inlet 260 operates merely as a connector to mate with outlet 262 of another gas container module 210 and can be excluded in an alternative embodiment. Indeed, in Figure 5B, gas container module 210 is illustrated without inlet 260.

[0050] In the illustrated embodiment, conduit 234 of connected gas container modules 210 (via connected inlets 230 and outlets 232) transport air to conduits 34 and 34a of testing modules 10 and 10a, respectively. Gas container module 210 for test gas 1 (contained in cylinder 400) is attached to first testing module 10 of the series of connected testing modules. In each of gas container modules 210, the test gas cylinder connected thereto is in fluid connection with second (counting outlet 232 as the first merely for reference) outlet 242. In the case of gas container module 210 for test gas 1 (subsequently referred to as first gas container module 210) connected to first testing module 10 of the series of connected testing modules, second outlet 242 is connected to second (counting inlet 30 as the first) inlet 40 of testing module 10, thereby transporting test gas 1 through second conduits 44 and 44a of testing modules 10 and 10a, respectively. As second inlet 240 of each of gas container modules 210 is in fluid connection with third outlet 252 thereof via conduit 244, test gas 2 is transported from outlet 242 of second gas container module 210 (through inlet 240 and conduit 244 of first gas container module 210) to third outlet 252 of first gas container module 210, and thereby through third conduits 54 and 54a of testing modules 10 and 10a, respectively. Once again, as second inlet 240 of each of gas container modules 210 is in fluid connection with third outlet 252 thereof via conduit 244, test gas 3 is transported from outlet 242 of third gas container module 210 (through inlet 240 and conduit 244 of second gas container module 210) to third outlet 252 of second gas container module 210, and thereby through third

inlet 250 of first gas container module 210. As third inlet 250 of each of gas container modules 210 is in fluid connection with fourth outlet 262 thereof via conduit 254, test gas 3 is transported from third inlet 250 of first gas container module 210 (through conduit 254 of first gas container module 210) to fourth outlet 262 of first gas container module 210, thereby transporting test gas 3 through fourth conduits 64 and 64a of testing modules 10 and 10a, respectively.

[0051] This cascading flow algorithm can be repeated for additional gas container modules connected in series (and further, to additional testing modules connected in series) simply by providing more inlets, outlets and connecting conduits. In the case of the gas container modules, the first inlet and outlet can be dedicated to the flow of ambient air. Likewise, the second outlet of a gas container module can be dedicated to the flow of gas from a gas cylinder in operative connection with that gas container module. For the second inlet, third inlet, fourth inlet etc., a fluid connection can be made between the inlet and the subsequent outlet (that is, the third outlet, fourth outlet, fifth outlet etc., respectively). In other words, referring to, for example, the second inlet as I ₂ and the third outlet as O3, inlet I ₁ is in fluid connection with outlet O _1+I for each gas container modules wherein x is greater than or equal to 2. For a total of X+l outlets, there need be only X inlets as one outlet is dedicated to the gas container seated in the gas container module.

[0052] In the illustrated embodiments, the resulting "cascading" flow through a plurality of gas container modules connected in series results in ambient air being transported through outlet Oi of the first gas container module (that is, the gas container module connected to the first of the series of testing modules). Gas Y is transported through outlet Oy _{+ 1} of first gas container module, wherein Y designates the position of the gas container module in the series of connected gas container modules (that is, Y is 1 for the first gas container module, 2 for the second gas container module etc.).

[0053] Of course, other flow configuration can be used. For example, the last inlet/outlet pair can be dedicated to air, and cascading flow can occur in the inlets and outlets above the air flow. The air flow inlet/outlet pair can also be positioned elsewhere. Moreover, virtually any geometry or configuration other than a generally linear alignment of inlets/outlets can be used. For example, inlets and outlets can be placed in a generally circular arrangement with cascading flow occurring around the circle in a manner as generally described above.

[0054] In one embodiment, each of the testing modules of the present invention is provided with a power connection, which can be powered via AC power form a power outlet. DC power can be provided, for example, from a vehicle module connectible to a vehicle battery or via DC power from a battery back 90 as illustrated, for example, in Figures 1 and 3A. In this embodiment, battery pack 90 includes four batteries 92a, 92b, 92c and 92d (which can be rechargeable) retained within battery back 90 via a retainer 94. An electrical connector 96 on battery pack 90 forms an electrical connection with a cooperating connector 82 (see Figures 1 and 3A) of testing module 10 (or a like testing module). The housing of battery pack 90 is adapted to connect to flange 24' of testing module 10 in a manner similar to that described above for connection of flange 24' to flange 24a. In certain embodiments, battery pack 90 can be used in connection with only a single testing module. However, suitable electrical power connections can be provided between testing modules so that a single battery pack can power multiple testing modules connected in series.

[0055] Testing module 10 (and like testing modules) can be provided with a communication slot 84 into which a memory card 86 (see Figures 1 and 3A) can be placed in communicative connection. Memory card 86 (which can be in communicative connection with the microprocessor of the testing module) can, for example, provide data storage and print record capability in addition to that available in testing module 10 without memory card 86. In the case that a battery pack 90 or a network interface 120 (see Figures 6A and 6B) as described below is not installed, an

end cap 1 10 (see Figure 3B) is preferably placed in connection with flange 24'. End cap 1 10 can, for example, provide protection for memory card 86 and other components positioned within the confines of flange 24'.

[0056] As illustrated, for example, in Figure 9, communication connections are provided between a testing module and the gas detector in operative connection therewith as well as between connected testing modules of the present invention. Using such communication connections, a single memory card 86 can communicate with a plurality of testing modules connected in series. Likewise, as illustrated in Figures 6 A and 6B, a network module 120 can be placed in communicative connection via a communication port 89 (see Figure 3A) with the last testing module of a series of connected testing modules to provide network communication (either wireless or wired network communications as known in, for example, the computer arts) with all testing modules of the series. Communication port 89 and a cooperating communication port 89' (see, for example, Figures 1 , 2 A and 2B0 can also be used to effect communication between connected testing modules.

[0057] In a similar manner, communication can be provided between gas container modules 200 which are connected in series and/or between gas container modules 210 and testing modules 10, 10a, etc. or other networked components. Communication from gas container modules 200 can, for example, be desirable in the case that gas container modules 210 include one or more sensors 250 adapted to read data from one or more indicators 410 and 410a on gas containers 400 and 400a, respectively, as illustrated in Figure 6 A. Indicators 410 and 410a can, for example, provide data on the composition, pressure, volume etc. of gas contained therein, which can be read by one or more sensors 250 of gas container modules 210 and, for example, communicated to testing modules 10 and/or 10a. Indicators 410 and 410a can, for example, be RFID (radio frequency identification) tags. Alternatively, indicators 410 and 410a can be optical bar indicators as known in the art, in which case, sensors 250 can be optical scanners as known in the art. Likewise, many other indicator/sensor pairs are suitable for use in the present invention.

[0058] As best illustrated in Figure 6A, the bottoms of the testing modules and the gas container modules of the present invention can be made to be sufficiently flat to enable use of the gas testing systems of the present invention on a table 600 or other surface. Furthermore, the rearward side of the testing modules and gas container modules of the present invention can be formed with appropriated cooperating connectors to allow attachment thereof to one or more DIN rails. In Figure 10, for example, gas container module 210 is illustrated with connectors 229 on a rearward side thereof to connect gas container module 210 to DIN rails 700. DIN rails 700 can, for example, be mounted on a wall using mounts 710 as known in the art.

[0059] In several embodiments of the present invention, the rearward or back portions or sections of the housings for the testing modules and the gas container modules (which include the inlets, outlet, communication ports etc.) were fabricated to be generally identical (see, for example, Figures 1, 3 A, 5B and 5C. Different front section where then attached to the back sections to form the testing modules and the gas container modules.

[0060] Although the present invention has been described in detail in connection with the above embodiments and/or examples, it should be understood that such detail is illustrative and not restrictive, and that those skilled in the art can make variations without departing from the invention. The scope of the invention is indicated by the following claims rather than by the foregoing description. All changes and variations that come within the meaning and range of equivalency of the claims are to be embraced within their scope.