GB2559704B

GB2559704B - Gas monitoring apparatus for use with interchangeable sensor modules

Info

Publication number: GB2559704B
Application number: GB1808463.2A
Authority: GB
Inventors: Naylor John; Simon Edward Talbot Charles; Christopher White David; Paul Ford Christopher; Stone Carl; Williamson Alistair; Hodgin Andrew; Wong Jan
Original assignee: Cgd Tech Ltd
Current assignee: Cgd Tech Ltd
Priority date: 2015-04-03
Filing date: 2015-04-03
Publication date: 2019-11-06
Anticipated expiration: 2035-04-03
Also published as: GB201808463D0; GB2559704A

Description

Gas Monitoring Apparatus for use with Interchangeable Sensor Modules

The present invention relates to a device and apparatus for gas monitoring. In particular, the present invention relates to a gas monitoring device and apparatus having interchangeable gas sensor modules.

It is desirable to monitor gas emissions in a variety of possible locations in order to track emissions of gases and assess site conditions. Such locations include landfill and brownfield sites, onshore oil and gas sites and carbon capture storage sites. In all applications, it is necessary that the gas monitoring equipment used is able to obtain a statistically valid representation of the emissions present. To do this, it is necessary to collect a large quantity of data, either by making repeated visits to a site or, more desirably, by leaving equipment in place that is capable of continuously monitoring and storing data.

Device

According to an aspect of the invention there is provided a device for a gas monitoring apparatus, comprising: a manifold having a plurality of sensor ports, each sensor port being configured to couple with an interchangeable sensor module, wherein the manifold is arranged to define a single gas flow path, such that a gas flowing through the manifold will flow via each sensor port; a gas inlet and a gas outlet, which are fluidly connected via a first valve and via the manifold; and a further gas inlet that is arranged to bypass the manifold to the gas outlet via a second valve and via a gas flow rate sensor.

The sensor ports may be distributed in-line along the gas flow path, such that a gas will flow past each sensor port in turn. The sensor ports may be distributed evenly along the flow path. The sensor ports may be configured in a generally circular arrangement.

The manifold may comprise a first part, a second part and, preferably, a gasket positioned between the first and second parts, wherein a plurality of channels are defined in the gasket to define the gas flow path between sensor ports. Alternatively, the manifold may be formed as a single part with a gas flow path provided inside it, or two parts defining a gas flow path, whereby a gasket is required to seal the two parts together.

The plurality of channels may be provided in a sequential series, wherein each channel extends between two sensor ports.

Adjacent channels may be Interrupted by a rib member that extends across the sensor port, whereby a gas flowing along the gas flow path is caused to flow over the rib info the sensor port. Each channel may begin and/or ends in a semicircular opening. Two or more adjacent channels may form a substantially circular opening beneath a sensor port, the opening being dissected by a rib of gasket.

The manifold may further comprise a single gas inlet and a single gas outlet, positioned one at each end of the gas flow path. The manifold may have a uniform cross-section. The manifold may be generally circular, although other shapes and configurations may be possible.

The manifold may further comprise a printed circuit board (PCB) arranged to interface with a coupled sensor module. The PCB may comprise control circuitry configured to communicate with control circuitry in a coupled sensor module to detect a sensor housed therein. The PCB control circuitry within the sensor modules may be further configured to calibrate the sensor housed in a sensor module automatically according to stored parameters, preferably wherein the PCB control circuitry is configured to hold calibration data for the or each sensor.

The device may further comprise a pump arranged to pump gas along the desired gas flow paths.

The device may further comprise a plurality of interchangeable sensor modules, each arranged to couple with one (and preferably any) of the sensor ports.

Sensor module

According to another aspect of the invention there is provided a sensor module for use with the device described above. Preferably, the sensor module is arranged to able to couple with one or more of the sensor ports of the device.

The sensor module may be arranged to have a push-fit coupling with a sensor port. The sensor module may be an injection moulded enclosure.

The sensor module may further comprise a printed circuit board (PCB) arranged to receive a sensor, preferably wherein the PCB has control circuitry for interfacing with a sensor mounted to the PCB. The sensor may be detachable from the PCB, which is preferably configured to receive a plurality of different types of sensor. The control circuitry may be arranged to communicate the type of sensor housed therein to control circuitry of the device such the sensor coupled to a particular sensor port can be determined. The control circuitry may comprise an identifier of a serial number of the sensor The control circuitry may comprise calibration data for each type of sensor.

The sensor module may further comprise a shoulder portion for abutting the manifold when coupled with a sensor port, the shoulder portion being provided with at least one electrical contact arranged to provide an electrical connection between the sensor module PCB and the manifold.

An aperture may be provided on a surface of the sensor module that is arranged to expose a sensor housed therein to the gas flow path. The aperture may be substantially circular. The aperture may be dissected by a rib arranged such that the aperture provides a gas inlet and a gas outlet to the sensor module, when coupled with a sensor port.

Sensor kit

According to another aspect of the invention there is provided a kit of parts comprising a sensor module and a sensor for sensing a gas variable, preferably for use with the device described above.

The kit of parts may further comprise a plurality of different sensors for sensing a gas variable, wherein the sensor module may be arranged to house any one of the sensors. The sensor module may be arranged as described above.

The kit of parts may comprise a plurality of sensor modules each having a substantially identical size and shape. Preferably, each sensor module is capable of being coupled with any sensor port in the manifold of the device.

Apparatus

According to another aspect of the invention there is provided an apparatus for gas monitoring, comprising a device as described above. The apparatus may further comprise a housing including a main body arranged to contain the device and a separate cover arranged to seal the device within the main body. The cover may be resealable, and preferably detachable from the main body.

The cover may be arranged to retain one or more sensor modules within its respective sensor port in the manifold of the device. One or more ribs and/or projections may be provided on the underside of the cover and arranged to come into contact with the one or more sensor modules when the cover is closed, thereby to retain them.

The cover may further comprise a gas inlet and/or a gas outlet arranged in fluid communication with the device, or more preferably the manifold. The cover may be further arranged to receive a removable means for collecting a gas sample (such as a sorbent tube or a Tedlar bag, for example) for the collection of a gas sample from a gas flow path within the apparatus, preferably via a manually operated valve. The collecting means may be connected via a push-fit connector.

The cover may further comprise a power source arranged to provide a power supply to the device. The power source may be a rechargeable battery. Electrical contacts may be provided in the cover, which are arranged to be brought into contact with corresponding electrical contacts in the main body when the cover is closed. The power supply from the power source to the device may be interrupted when the cover is open.

The cover may further comprise a radio module, arranged to transmit data obtained from a sensor housed in a sensor module coupled to a sensor port. The radio module may be further arranged to receive configuration data for calibrating sensors. The radio module may be detachable from the cover. The radio module may be configured to communicate with one or more similar apparatus for providing a network of apparatus. A repeater device may be provided, configured to extend the range of communication of an apparatus.

The apparatus may further comprise tamper evidencing means arranged to indicate if the cover has been opened and/or moved from the housing. Tamper evidencing means may also be provided to indicate if the housing has been moved or otherwise disturbed.

The apparatus may further comprise a gas inlet and a gas outlet, both fluidly connected to the manifold. The gas inlet may be provided underneath the main body. The (or a further) gas inlet may be provided underneath the main body that is arranged to bypass the manifold to the gas outlet via a differential pressure sensor for detecting the pressure at the gas inlet, A (yet) further inlet may be arranged to inlet atmospheric air into the apparatus. A hydrophilic filter may be provided at the (yet) further inlet. A moisture stripping filter may be provided in the gas flow upstream (prior to) of the manifold and before the gas flow reaches the sensors.

The gas outlet may be arranged to vent to atmosphere. A filter, preferably one that is hydrophobic, may be provided at the gas outlet. A further gas outlet may be provided, said further gas outlet arranged to vent underneath the main body. A gas outlet valve may be provided downstream of the manifold that is controllable to direct the route of the gas flow path either to the gas outlet arranged to vent to atmosphere or to a further gas outlet arranged to vent beneath the main body. A gas safety valve may be provided upstream of the manifold, controllable to direct the gas flow path directly from the gas inlet to a gas outlet, and by-pass the manifold.

At least one solenoid valve may be provided to contra! gas flow through the apparatus. A gas flow rate sensor may be provided to detect the rate of flow of a gas flowing from a gas inlet through the apparatus and/or manifold.

The apparatus may also include means for monitoring water levels in the apparatus and a circuit breaker to prevent water damage when a predetermined level has been exceeded. Ideally, the apparatus will automatically switch off and/or be sealed if the water level is too high.

The apparatus may also include a pressure protection shut down arrangement, for when excessive pressures are detected to avoid damage to the apparatus, whereby gas may be routed (preferably, via a bypass) to outlet directly to atmosphere.

Preferably, the apparatus is configured to fit inside a 20cm (8”) flush fit borehole head-works.

Base

According to another aspect of the invention there is provided a base for mounting an apparatus as described above, wherein the base is separable from the apparatus.

The base may further comprise at least one gas inlet arranged to connect fluidly to a corresponding at least one gas inlet of the main body. A filter may be provided, arranged to condition gas entering the apparatus via the gas inlet before it reaches the main body of the apparatus. A plug adaptor may be arranged to be attached to an underside of the base, wherein the plug adaptor is configured to plug a conduit from which gas to be monitored may be emitted, such that the apparatus can be mounted onto the conduit, wherein the conduit is preferably a stand pipe. A plug adaptor may be provided, arranged to be attached to an underside of the base, wherein the plug adaptor has an aperture arranged to receive a conduit from which gas to be monitored may be emitted and, preferably, to provide a substantially gas-tight seal about the conduit.

The aperture may be configured to receive conduits of different diameter, wherein the aperture may have a diameter of less than 200mm, preferably between 10mm and 120mm, more preferably between 20m and 100mm, even more preferably between 30mm and 90mm, even more preferably between 45mm and 75mm, even more preferably between 50mm and 70mm, and preferably about 63mm. A base may be supplied with a kit of rubber inserts having a range of diameters configured to adapt the aperture size to receive a conduit.

The base may be provided with an external power supply arranged to supply power to a mounted apparatus.

Preferably, the term “interchangeable” (and derivatives thereof) used herein with reference to the gas sensor module may connote a gas sensor module that is available to be decoupled from the sensor port to which it is coupled and replaced by another gas sensor module that is coupled to the sensor port in its place.

As used herein, the term “downstream” preferably connotes a point in a fluid flow path that is further along (i.e. past) a datum point in the direction of flow, and the term “upstream” preferably connotes a point in a fluid flow that has yet to reach (i.e. is before) the datum point.

Given the hazardous environments in which the apparatus may be used, it is preferably designed to meet the requirements of the British Standard (BS) EN 60079-0 (in particular clause 7.4) guidance for equipment that is to be used in explosive atmospheres, such as Zone 0 IIC environs. Furthermore, the apparatus should, ideally, be able to withstand dusty environments and water immersion, in accordance with IP67 (as per the IEC standard 60529).

An exemplary embodiment of the present invention will now be described, with reference to the accompanying drawings, in which:-

Figure 1 shows an apparatus (including a device according to the present invention) for gas monitoring mounted on a base;

Figure 2a shows the apparatus separated from the base;

Figures 2b and 2c show the base in isolation, and the base having a ‘plug’ adaptor, respectively;

Figure 2d shows an underside of the base in Figure 2b;

Figure 3 shows the apparatus mounted atop a conduit (standpipe) in a head works;

Figure 4 shows a disassembled view of the apparatus;

Figures 5a and 5b show different views of a manifold assembly;

Figures 6a and 6b show how the gas sensor modules are retained in the manifold assembly by the cover;

Figure 7 shows a cut-away sectional view of the manifold assembly ;

Figure 8 shows a further cut-away internal view of the manifold assembly;

Figure 9 shows a range of different gas sensors that might be housed in a gas sensor module for coupling to the manifold assembly;

Figure 10 shows a cut-away internal view of an apparatus for gas monitoring; Figure 11 shows a further cut-away internal view of the apparatus;

Figure 12 shows an apparatus with a cover having a detachable radio module; Figures 13a to 13c show alternative views of the detachable radio module;

Figure 14 shows the apparatus having a retractable carry handle;

Figure 15 shows a flow chart showing gas flow routes through the apparatus; Figures 16a to 16b show a schematic diagram of components of the apparatus; Figures 17a to 17e show different possible gas flow routes through the apparatus; Figures 18a to 18d show a solenoid valve that may be used in the apparatus; and Figures 19a to 19c show a gas filter that may be used in the apparatus.

Figure 1 shows an exemplary apparatus 10 for gas monitoring mounted on a separable base 200. The apparatus 10 comprises a main body 103 and a cover 101, which together form a housing 100. The cover 101 may be removable (or detachable) from the housing 100, but is preferably resealable. A gasket seal 121 may be provided between the cover 101 and the main body 103. The cover 101 may comprise a removable power source 102, a carry handle 132, and a radio module 113 as will be described further on. The cover 101 may be attached to the main body 103 using suitable fixings (not shown here).

Figure 2a shows the apparatus 10 with the base 200 detached. Figure 2b shows a base 200 comprising a bottom section 201 which may be transparent and/or which may be lit by LEDs provided inside the bottom section 201. The bottom section 201 may also be provided with a sounder 202 on its underside to provide indicators or warnings of activity and gas levels. The base 200 may comprise a release mechanism 260 using a key (or similar) to unlock the base from the housing 100 of the apparatus 10. A corresponding mechanism 160 may then be provided on the housing 100. Furthermore, the base 200 may comprise an external power supply (not shown).

The apparatus 10 may be connected to the base 200 using a spring-loaded retaining plate 161 (not visible in this figure) provided on the base of the apparatus 10 which interfaces with pins (not shown) provided on the base 200. A spring 165 (not shown in Figure 2a) is used to bias against the retaining plate. Locating pins may be provided on the base 200 and corresponding holes on the underside 167 of the apparatus 10 to aid alignment of the two parts.

As shown in Figure 2b, the base 200 may be provided with several openings 21, 22, 23, 24 for receiving tubing 150 (or a similar fluid conduit) from the apparatus 10. The openings 21, 22, 23, 24 allow gas connections to be made through to an underside of the base 200, where corresponding gas inlets 31, 32, 33 and gas outlet 34 are provided to allow fluid to enter and leave the apparatus 10. These gas inlets may be referred to herein as the “main” gas inlet 31, the “manual” gas inlet 32, the “bypass” gas inlet 33 and the gas outlet may be known as the “recirculation” gas outlet 34.

The base 200 may be provided with a plurality of valves 114 (not shown) which controls gas flow through the openings 21, 22, 23, 24. Additionally, electrical connections 209 and a PCB 207 (not shown in Figures 2a to 2d) may be provided so as to allow the base 200 to be powered and controlled via valve control drivers, which may be solenoid driven. The base 200 may additionally comprise a differential pressure sensor 144 (not visible in Figures 2a to 2d) which will be detailed further on. Preferably, an auxiliary socket (not shown), may be provided on the bases 200 for the connection of other equipment.

Figure 2c shows a 'plug’ adaptor 300 secured to the base 200. The adaptor 300 may be secured to the base 200 via a conventional fixing means such as a ‘nuts and bolts’ arrangement that passes through holes 306, for example. A plug adapter 300 may be used when the apparatus 10 is to be placed over a monitoring well stand pipe, for example, as illustrated in Figure 3. The plug adapter 300 is shaped to plug the stand pipe 307 so that gas present in the stand pipe 307 may enter the plug adapter 300 and from there be fed into the apparatus 10 mounted above. A stand pipe may have a 63mm diameter opening, for example, though a stand pipe may be chosen from stand pipes having a range of different diameters, although typically with a diameter of less than 200mm.

Alternatively, the plug adapter 300 may be configurable to be placed over a nonstandard well stand pipe 307 (or a similar conduit), as explained further on. The plug adapter 300 may be provided with means for filtering 310 (not shown) excessive moisture and/or particulates from the gas before allowing it to enter the apparatus 10 mounted on the base 300.

If the plug adaptor 300 is not used, a bypass fluid conduit may be attached to the base 200 so as to complete the gas flow path and allow the apparatus 10 to function.

Figure 2d shows the underside of the base 200. The gas inlets 31, 32, 33 and the gas outlet 34 of the gas flow path can be seen protruding out of the underside of the base 200. When the plug adaptor 300 is attached to the base 200, these inlets 31, 32, 33 and the outlet 34 are exposed through an aperture provided in the plug adaptor 300, The base 200 may be provided with humidity and temperature sensing means 203 and inlet pressure sensing means 204, as shown here and in outline in Figure 3.

Figure 3 shows an example of the apparatus 10, in use, mounted to a base 200 having a plug adapter 300 fitted. As described above, the plug adaptor 300 is placed over a stand pipe 307 (or similar fluid conduit), which has been cemented into a monitoring well (not shown) to seal it, inside headworks 308. The apparatus 10 is enclosed within the headworks 308 under a cover 302. The aperture of the plug adaptor 300 is arranged to fit over the end of the stand pipe 307 and provide a gas tight seal around it. Rubber inserts 301 may be used to adapt the plug adaptor 300 to be fit over stand pipes 307 of different sizes.

Figure 4 shows a disassembled view of the apparatus 10 with the cover 101 detached from the main housing 100. Certain componentry has been omitted from this view to aid clarity, A manifold assembly 109 is shown, generally comprising a manifold 107 and a printed circuit board (PCB) 148 having mounted thereon various componentry (described further on). The PCB 148 is suspended beneath the manifold 107 by support members 149.

Several gas inlets are provided on the underside of the PCB 148 of the manifold assembly 109: a “main” gas inlet 11, a “manual” gas inlet 12 and a “bypass” gas inlet 13. Gas entering either the manual gas inlet 12 or the bypass gas inlet 13 passes through the duct 108 and bypasses the manifold 107, A gas outlet 14 is also provided. The three inlets 11, 12, 13 and the outlet 14 are arranged to connect with the corresponding openings 21, 22, 23, 24 in the base 200 via a plurality of fluid conduits 150 provided in the main body 103 of the apparatus 10, The openings may be provided with barbs 11, 12, 13, 14, improving the security of the fluid connection.

Figures 5a and 5b show further views of the manifold assembly 109 removed from the housing 100. A plurality of sensor ports 118 are provided in the manifold 107, each sensor port 118 shown having a detachable sensor module 110 coupled thereto. The manifold 107 shown has eight sensor ports 118 arranged in a generally circular configuration. The sensor modules 110 are arranged to sit in the sensor ports 118, and are held in place when the cover 101 is closed by retaining members 166 (best visible in Figure 4 and Figures 6a and 6b) which extend from the cover 101.

The manifold 107 provides a gas flow path for gas to be sensed, which extends between a gas inlet 116 and a gas outlet 117, which are located underneath the manifold 109 in Figure 5b. The sensor ports 118 are, preferably, located in-line in the gas flow path and are, preferably, distributed evenly around the manifold, such that gas flowing through the flow path passes each sensor port 118 in turn. The manifold 107 in this apparatus 10 is arranged so as to minimise the length of the gas flow path and thereby minimise the volume required by the manifold 107 and coupled sensor modules 110. Accordingly, the manifold 107, ideally, has a substantially circular arrangement, and may be described as a “ring” or “horseshoe” manifold 107.

It will be appreciated that when the apparatus 10 is used in a monitoring well, for example, the cover 101 may be removed and the sensor modules 110 may be easily detached and replaced, without the manifold 107 or the main body 103 of the apparatus 10 having to be removed from the monitoring weli.

The manifold assembiy 109 may also comprise a duct 108, which houses electrical connections and fluid conduits 150 to direct at least part of the gas flow path through the apparatus 10. The duct 108 is arranged to be received by a corresponding opening 120 in the cover 101, in a plug and socket type arrangement, when the cover 101 is closed against the main body 103 such that both fluid and electrical connections are provided between the main body 103 and the cover 101 of the apparatus 10, as will be described further on.

The manifold assembly 109 may also comprise a plurality of flow-control valves 114 to control the gas flow through the manifold 107. The manifold assembiy 109 may also comprise a pump 112 positioned at the manifold outlet 117 which acts to draw gas through the apparatus 10. The manifold assembly 109 may also comprise fluid conduits 150 arranged to connect components of the apparatus 10 to the inlet 116 and outlet 117 on the manifold 107. These components may be mounted on the PCB 148, which may also be provided with a processor, memory card, and, optionally, an internal temperature sensor (not shown).

Figures 6a and 6b show the manifold 107 installed in the body 103 of the apparatus 100, having sensor modules 110 present in each sensor port 118. The underside of the cover 101 is provided with a plurality of retaining members 166 arranged to retain the sensor modules 110 in their respective ports 118 when the cover 101 is closed on the body 103. Securing means 168 may be used to secure the cover 101 to the body 103. The cover 101 is shown without a power source 102 or radio module 113 fitted.

The dose-υρ “cut-way” sectional view in Figure 6b shows a sensor module 110 (containing a sensor 104) being retained by a retaining member 166 in a sensor port 118 of the manifold 107.

Figure 7 shows a “cut-away” sectional view of the manifold 107, illustrating the internal componentry of the sensor modules 110. A gasket sea! 157 may be provided at the bottom of the sensor port 118 to ensure that the manifold 107 is sealed when all sensor modules 110 are coupled to the manifold 107 and the cover 101 is closed. The gas outlet 117 from the manifold 107 is shown connecting to the sensor module 110 positioned at the end of the gas flow path in the manifold 107.

The sensor modules 110 are, ideally, arranged so as to be of the same size and shape, such that the sensor modules 110 may be interchangeable irrespective of which sensor 104 is housed inside the sensor module 110.

As can be seen from the cutaway views, each sensor module 110 houses a sensor 104 which interfaces with a control circuit 111 having electrical connections 133 connecting the sensor 104 to the manifold 107. A PCB 147 may be provided as part of the manifold assembly 109, whereby this ‘manifold’ PCB 147 may be electrically connected via the ‘duct’ PCB 141 provided inside the duct 108 to the ‘main’ PCB 148 suspended beneath the manifold 107. The sensor module 110 may be provided with a shoulder portion 136 which can rest on the ‘manifold’ PCB 147 and which houses electrical connections 133 that interface with the PCB 147. Thus, an electrical connection may be provided between the sensors 104 and the ‘main’ PCB 148. The control circuits 111 and the PCBs 147, 148 may communicate via a suitable communication bus.

The control circuit 111 in the sensor module 110 is configured to identify the sensor 104 present to the processor on the main PCB 148. The apparatus 10 is thereby capable of recognising different sensors 104 (for example, by product serial number) and their location within the manifold 107 (i.e. which sensor port 118). This allows sensor modules 110 containing different sensors 104 to be used interchangeably in the apparatus 10 such that sensor modules 110 can be selected and easily installed into the manifold depending on the required functionality of the apparatus 10.

The control circuits 111 in the sensor modules 110 may additionally be capable of recognising the electrical requirements for a given sensor (such as whether a sensor requires low Voltage (V), e.g. 2V, or high Voltage, e.g. 5V), controlling the electrical input to a sensor (so that the sensors are either “on” or “off”), performing a diagnostic check procedure and/or saving component calibration data and life expectancy data.

Sensor modules 110 that do not contain a sensor 104 may be adapted to be used as ‘blanking’ modules arranged to close off a sensor port 118, while allowing gas to continue along the gas flow path. The sensor ports 118 may be further adapted to couple with sensor modules 110 configured for purposes other than containing sensors 104, such as specialist gas conditioning modules, sampling modules, and modules containing a fluid for calibrating sensors, that exploit the fluid and/or electrical connections provided on the manifold.

As best illustrated in Figure 6b and Figure 7, each sensor module 110 is arranged to provide a chamber 140 beneath the gas sensor 104 when the sensor module 110 is coupled with a sensor port 118. A generally circular aperture 142 is provided at the bottom of the sensor module 118, opening into the chamber 140 and thereby exposing the sensor 104. Preferably, a rib 126 extends across the aperture 142.

The duct 108 has electrical connections 134, preferably provided on a PCB 159 mounted on an upper surface of the duct 108, which is arranged to protrude through the opening 120 so that the electrical connections 134 come into contact with corresponding electrical connections 135 provided on the underside of the cover 101, when the cover 101 is closed. Electrical power may be supplied via these electrical connections 134, 135 to components within the main body 103, such as the componentry on the manifold assembly 109 and the valves 114,

The arrangement of electrical contacts 134, 135 may comprise sprung conductive elements having raised barbs to ensure a good electrical connection. When the cover 101 is removed to allow access to the apparatus 10, the power to the apparatus 10 is interrupted due to the electrical connections 134, 135 becoming separated. The electrical connections 135 may also be used to transmit data and control information.

Electrical connections which are provided at ieast partly inside the duct 108 interface with the base electrical connections 209 to provide electrical power to the components in the base 200, such as the valves 114, warning light 201 and sounder 202. Preferably, these electrical connections are provided by a vertically-mounted PCB 141 provided inside the duct, as shown in Figure 4. This PCB 141 may also be referred to as a “cactus board”.

The manifold 107 shown comprises an upper part 161, arranged to define the sensor ports 118, a middle part 162, and a lower part 163. A gasket 157 is provided between the upper part 161 and the middie part 162 to provide a gas-tight seal between the two parts 161, 162, which together define the sensor ports 118. The upper part 161 and middle part 162 could alternatively be combined as a single upper part that defines the sensor ports 118. Another gasket 123 is provided between the middle part 162 of the manifold 107 and the lower part 163, whereby the gasket 123 is arranged to provide the gas flow path through the manifold 107. The gas flow path is arranged to flow via each sensor port 118 (and each coupled sensor module 100) in turn, by way of a plurality of channels 124 (or ‘cut-outs’) provided around the gasket 123.

More specifically, each channel 124 has an elongate section 124a connecting between two semi-circular sections 124b, 124c, opening outwardly from the channel 124a. Channels 124 are arranged adjacently around the gasket 123 such that a semi-circular section 124c of a first channel 124 adjoins a semi-circular section 124b of a second channel 124 thereby creating a substantially circular aperture in the gasket 123, which is dissected and thereby separated by a rib 156 that extends across the aperture between the two semi-circular sections 124b, 124c.

The generally circular aperture in the gasket 123 is arranged to correspond in size and shape with the aperture 142 of a sensor module 110 when coupled with a sensor port 118. The rib 156 acts to interrupt the gas flow path through the channels 124 around the gasket 123 and causes the gas to be diverted upwards into the chamber 140 of the sensor modules 110, where the gas is analysed by the sensors 104. Furthermore, the rib 156 in the gasket 123 is arranged to correspond to the rib member 126 that dissects the aperture 142 of a sensor module 110. The rib member 126 acts to cause the gas to flow further into the chamber 140 of the sensor module 110 so that it flows closer to the sensor 104 housed inside so that a better reading may be obtained by the sensor 104.

Alternatively, the manifold may be formed as a single part with a gas flow path provided inside it, or two parts defining a gas flow path, whereby a gasket is not required, in such an arrangement, the rib member 126 of the sensor module 110 may still deflect the gas flow into the sensor module 110.

The gas inlet 116 to the manifold 107 and gas outlet 117 may be provided in adjacent channels 124. The adjacent channels 124 may not have adjoining semicircular sections 124b, 124c. In this way, a gas flow path may be formed in which a gas introduced into the manifold 107 has to travel the length of the gas flow path, via each sensor port 118 (and hence each coupled sensor module 110) in turn before the gas can exit the manifold 107.

The gasket 123 is compressed between the manifold 107 and the lower part 163 such that a gas-tight seal is formed. The gasket 123 and areas of the manifold 107 in contact with sampled gases are preferably formed of chemically resistant and inert materials so as to not affect the gases being measured.

Figure 8 shows a further “cut-away” sectional view of the manifold 107 with sensor modules 110 installed. An arrow shows the flow path of a gas being drawn over the rib member 126 of sensor module 110, and thereby into the sensor module 110, as discussed above.

Figure 9 shows illustrative examples of gas detectors/sensors 104 of varying size and shape, which may be installed a sensor modules 110. The gas sensors 104 are, preferably, electrochemical gas sensors. Infrared sensors, ultrasonic sensors and semiconductor sensors may also be used to detect gases. Potentiostats may be used for electrolytic type sensors. Gases sensed may include (but are not limited to) Oxygen, Carbon Dioxide and other toxic and/or flammable gases.

The sensor 104 comprises a plurality of connecting pins 139 for interfacing with the control circuit 111; preferably the connecting pins are less than 5mm in height. The sensors 104 are, typically, circular and may have a diameter in the range of 17mm to 33mm, and a height in the range of 16mm to 18mm.

Figure 10 shows a cut-away internal view of the apparatus 10 mounted onto a base 200 having a plug adapter 300, with internal components and features exposed. It can be seen that the manifold assembly 109 fits tightly inside the housing 100 and engages with a plurality of fluid conduits 150 (which are provided on the underside of the cover 101 and beneath the manifold assembly 109 within the main body 103) which connect the openings 31, 32, 33, 34 on the underside of the base 200 (via the openings 21, 22, 23, 24) and the openings 105, 106, 122 in the cover 101 (which will be described in more detail later on) to the inlet 116 and outlet 117 of the manifold 107, creating a number of possible gas flow paths through the apparatus 10. As previously mentioned, a plurality of valves 114 are provided in the base 300 and in the manifold assembly 109 control gas flows through the apparatus 10, and more specifically which gas flow path is taken. The gas flow paths will be described in detail later with reference to Figures 15 to 17.

The fluid conduits 150 (or ‘tubing’) provided on the cover 101 engage with corresponding fluid conduits 150 which are provided on the manifold assembly 109 when the duct 108 of the manifold assembly 109 is fitted into the opening 120 on the cover 101. At least parts of the fluid conduits 150 are located within the duct 108. The fiuid conduits 150 provided within the main body 103 are configured to engage with the openings 11, 12, 13, 14 on the underside of the manifold assembly 109. The fluid conduits 150 may be barbed to allow for a “push-fit” fluid connection to be made, facilitating ease of set-up.

For efficiency, the path of all fluid conduits 150 is arranged in order to minimise the length of the path required. These fluid conduits 150 preferably comprise tubing which is formed from a compliant material but which may be sufficiently rigid to facilitate push-fit connections. Where the tubing is bent in order to conform to the internal volume of the apparatus 10, wide bends are taken to prevent restricting gas flow through the tubing as well as accidental disconnection of tubes.

Figure 11 shows a further cut-away internal view of the apparatus 10 mounted onto a plug adapter 300. As already mentioned, the plug adapter 300 comprises an aperture arranged to receive a stand pipe 307, or similar, into a chamber 304. The aperture is provided with a sea! 303, arranged to form a first gas tight seal around a stand pipe 307 (not shown) received into the aperture. The seal 303 is, ideally, in the form of a flexible rubber membrane. As previously mentioned, rubber inserts 301 could be used to reduce the aperture size to allow smaller diameter stand pipes 307 or fluid conduits to be received into the aperture.

The openings 31, 32, 33, 34 are shown within the chamber 304. The manual and bypass inlets 32, 33 both bypass the sensors 104 in the manifold 107. The bypass inlet 33 leads via a fluid conduit to a restriction orifice plate 184 and differential pressure sensor 144 and from there to the main atmospheric opening 105. The manual inlet 32 leads directly to an opening 106 in the housing 100 via a second fluid conduit. These external openings 105, 106 are described in more detail further on.

As mentioned above, the cover 101 comprises a power source 102 (preferably in the form of a rechargeable lithium battery pack), a radio module 113 (which may be attached to the power source 102), a RGB 119, and electrical connections 135 (which, optionally, may be mounted on a small RGB) from the power source 102 to supply power to the apparatus 10.

The cover 101 additionally includes three external fluid openings 105, 106, 122 (only opening 122 is shown in Figure 11). These openings have recesses to allow the shedding of water when installed horizontally. The first opening 105 is herein referred to as the "main atmospheric opening” 105, the second opening 106 is herein referred to as the “manual valve opening” 106 and the third opening 122 is herein referred to as the “bypass atmospheric opening.” Opening 122, ideally, is provided with a filter 143 for filtering excessive moisture and/or particulates from the gas before allowing it to enter the apparatus 10 mounted on the base 300. Preferably, the filter 143 comprises hydrophobic material. The opening 106, ideally, may further be provided with a manually operable valve 115 which is accessible from the exterior of the apparatus 10 and a cap 158 to prevent water ingress. Alternatively, a simple cap cover (not shown) for the opening 106 may otherwise be provided.

The power source 102 is connected to the cover 101 via security fixings 125 and is separately removable, so it can be charged away from the housing 100 or swapped for a replacement power source. The power source is arranged to have a watertight seal when connected to the cover 101. A charging point (not shown) is provided on the power source 102, preferably on an upper surface thereof.

The RGB 119 is located on top of the power source 102 and functions to protect the battery that comprises the power source 102. The RGB 119 controls all ATEX protection, power distribution and battery monitoring functions.

The gas pathway may comprise a removable sorbent tube 155. Known volumes of fluid can be passed through this sorbent tube 155, which can then be later analysed for specific compounds. The sorbent tube 155 is located horizontally above the sensor modules 110, on the underside of the cover 101 and, preferably, positioned between at least one tab 127 provided on the cover 101. The use of a tab 127 prevents bending and breakage of the sorbent tube 155 or fluid conduits 150. Where no sorbent tube 155 is required, the fluid conduits that would otherwise surround the sorbent tube 155 may be connected together, or a blank bypass tube inserted.

Figure 12 and Figures 13a to 13c show a radio module 113, and its connection to the apparatus 10. The radio module 113 may comprise a PCB 128 incorporating an antenna, an RF connector 138, an external temperature sensor 145, a pressure sensor 146, a Giobal Positioning System (GPS) chip (not shown), and/or a radio transceiver module (not shown).

The radio module 113 is secured to the power source 102 by means of security bolts 130. The radio module 113 is electrically connected to the power source 102 by means of sprung contacts 129. The contacts 129 may aiso be used to transmit data between the radio module 113 and the apparatus 10. The radio module 113 may be additionally provided with an activation switch (not shown) and LED 131 which lights to signify that the apparatus is active when being setup. This LED 131 turns off following set-up and deployment.

The antenna is located on the PCB 138 and is controlled to transmit and receive data (via a transceiver, for example) relating to a gas being monitored, sensors 110, other monitored parameters, location of the apparatus 10, instructions (such as on/off or sampling rates), diagnostic information, alerts and/or the status of the power source 102. The radio module 113 may be detached from the apparatus 10 so it can be better positioned to transmit and receive data. The radio module 113 may then be connected to the apparatus 10 via a connection lead (not shown).

Two or more apparatus 100 may be configured to communicate with one another and can thereby establish a mesh network via transceivers (not shown) provided in each apparatus 10.

Figure 14 shows the housing 100 of the apparatus 10 provided with a stowable carry handle 132 in an unstowed position. The handle 132 is affixed to the power source 102 and is stowed in a recess 137 (formed above and around the power source 102) of the housing 100 when not in use in order to reduce the envelope of the housing 100, for example when the apparatus is placed within monitoring well beadworks 308. The handle 132 is unstowed, as it is pivoted away from the recess 137, in order to carry the apparatus 10 by the handle 132. The handle 132 is designed to be resilient and as such is, preferably, formed from metal. The recess 137 is slightly sloped to allow water run-off when the apparatus 10 is positioned horizontally.

Figure 15 is a flow chart describing the different flow paths a gas may be controlled to take through the apparatus 10. The main gas inlet 31 in the base 300 is connected via a fluid conduit 150 to the manifold inlet 116 (via the filter 310). The external opening 122 is also connected to the manifold inlet 116. The manifold outlet is connected via a fluid conduit 150 to the pump 112 and the sorbent tube 155 (if present). A junction is provided at the outlet of the sorbent tube 155, providing connections to the external opening 105 in the cover 101 and re-circulation outlet 34 in the base 300. The bypass gas inlet 31 in the base 300 is connected via a fluid conduit 150 to the opening 105 in the cover 101, and the manual gas inlet 31 in the base 300 is connected via a fluid conduit 150 to the opening 106 in the cover 101. It will be appreciated that the valves 114 are located and controlled such that only one of the described flow paths is open as necessary to perform the defined measurement.

Figure 16a and 16b show two views of a schematic diagram of the components of the apparatus 10, which will be used to describe the possible flow paths in detail. In operation where the apparatus 10 is placed on a stand pipe 307, or similar pipe (using the plug adapter 300 as shown in Figure 3), gas enters the base 300 from an upstream direction and is directed along one of three flow paths, herein referred to as the “sensing” flow path and one of two “bypass” flow.

Figures 17a and 17b show the “sensing” route through the components of the apparatus 10, having two possible outlets. In this route, the gas enters the main inlet in the base (not shown) and passes through the filter 310. The gas is then delivered to a valve 114 and on to the manifold inlet 116. The gas is drawn into the manifold 107 and is analysed by the sensors 104 within the coupled sensor modules 110. The gas is then drawn from the manifold 107 through the sorbent tube 155 (where present) via the fluid pump 112. The gas may be continuously pumped through the manifold 107 for ongoing gas sampling and/or it may be held in the manifold 107 periodically, for analysis.

At this point, the gas may be directed along one of two routes. Along the first route, shown in Figure 17a, the gas is directed to the outlet 34 in the base 200. This provides a way to recirculate gas back down a stand pipe 307, or similar, following analysis. In the second route, shown in Figure 17b, the gas is directed to the main atmospheric opening 105 in the cover 101 of the housing 100, through which the gas is expeiled. This provides a way for gas to be expelled from the housing 100 following analysis. The sensing route thereby allows gas emanating from a stand pipe 307 to be analysed within the apparatus 10, after which it may be recirculated down the pipe (Figure 17a) or expelled to the atmosphere (Figure 17b).

Figure 17c and 17d show two possible “bypass” routes through the components of the apparatus 10.

In the route shown in Figure 17c, the gas enters the manual inlet 32 in the base 200 and is delivered to the opening 106 in the cover 101 of the housing 100, bypassing the manifold 107 entirely. The opening 106 is arranged so as to be accessible from the exterior of the housing 100. The purpose of this route is to provide the option of manually monitoring and collecting gas from the apparatus 10. In this route, gas from within the housing 100 is discharged through the opening 106 from which it can, for example, be collected in a sampling vessel for collection and ex-situ analysis.

Figure 17d shows the second “bypass” route through the components of the apparatus 10. in this route, the gas enters the bypass inlet 33, and passes through the differential pressure sensor 144, and is subsequently expeiled through the main atmospheric opening 105. The purpose of this route is to allow a flow-reading to be taken from the differential pressure sensor 144, which may then be stored into memory. The differential pressure sensor 144 may be used to determine the flow rate of the gas flow.

Figure 17e shows another route through the components of the apparatus 10, which allows the apparatus 10 to be used as a passive gas sensor and/or allows the system to be flushed using external air. This alternative gas route into the housing 100 is provided by the bypass atmospheric opening 122 on the cover 101, Gas entering the housing 100 via this opening 122 is delivered through a fluid conduit 150 to the manifold inlet 116. The gas is then drawn through the manifold 107 and sorbent tube 155 (where present) as described in the sensing route. It is then directed to the main atmospheric opening 105 in the cover 101 of the housing, through which the gas is expelled. The atmospheric gas route thereby allows atmospheric gas to be analysed within the apparatus 10, after which it is expelled from the apparatus 10 to the atmosphere. Unlike other flow paths described, this route can be used when the apparatus 10 is not mounted on a stand pipe 307, or similar pipe. For example, the apparatus 10 could be attached to the wall or floor using the ‘cradle’ base 200 as shown in Figure 2 and suitable fixing means.

The apparatus 10 may be arranged to run a “self-test” mode, wherein the valves 114 positioned upstream and downstream of the manifold 107 are closed and the pump 112 is then run in reverse in order to identify any leaks within the manifold 107 by subsequently measuring pressure within the apparatus 10. This pressure measurement may be taken using the inlet pressure sensing means 204 provided in the base 200. It will be appreciated the apparatus 10 may be arranged to selftest in a variety of alternative ways. The apparatus 10 may also be arranged to run a “purge” mode, in which all sampled gas is expelled from the apparatus 10.

Figures 18a to 18d shows an example of a solenoid valve 114 that might be used within the apparatus 10 to control gas flow. The valve 114 comprises a solenoid 151, a spring 152, a piston 153, and a chamber 154. The chamber 154 has broadly triangularly shaped side walls and is connected to two fluid conduits 150 at either side of the chamber, such that in the open position a flow path is created. The piston 153 is shaped such that, in the shut position, it fits into the side walls of the chamber 154 so as to block the flow of fluid through the chamber 154. Space is provided within the chamber 154 so that the piston 153 may shuttle between the closed and open positions.

The spring 152 is provided at the end of the piston 153 away from the chamber 154 and is biased to keep the piston 153 in the open position. The solenoid 151 is provided underneath the piston 153 and spring 152. When the solenoid 151 is activated, the piston 153 moves away from it, dosing the valve 114, When the solenoid 151 is deactivated, the valve 114 opens due to the biasing action of the spring 152.

Figures 19a to 19c show a filter 310 which is provided in the base 300, to which the main inlet 31 and the manifold 107 is fluidly connected. The filter is connected to the housing 100 of the base 300 by means of a clip 311. The filter 310 acts to condition moisture ieveis and, ideally, particulates from entering the main body-103. The filter 310, preferably, contains hydrophilic fluid conditioning material 312, contained within the filter 310 by a pair of bungs 313 provided at the ends of the filter 310. Holes in the bungs 313 are provided, in order that a fluid flow path may be formed with fluid conduits 150. When the apparatus 10 is mounted to the plug adaptor 300, all gas entering the main gas inlet 31 passes through the filter 310 (and therefore the hydrophilic materia! 312) before reaching the manifold 107. As previously mentioned, when base 300 is not present, a bypass fluid connector is positioned across the filter connection points.

The apparatus 10 may further comprise sensors to measure water proximity sensing means. The housing 100 may be provided with security fixings, for example by means of security bolts, in order to provide access to the components contained within the housing 100. The housing may comprise means for fastening the apparatus 10 to a structure (such as a wall or headworks) from which it is desirable to measure gas. The means for fastening, for example, may comprise a grommet or eyelet through which the apparatus 10 is bolted.

It will be appreciated that alternative components and flow paths may be used to perform the functions of the apparatus 10. in particular, the valves 114 used may differ, with the system of (preferably solenoid) valves 114 being replaced by a smaller number of three-way valves, for example.

The apparatus 10 may be provided with tamper resistant means (not shown) and/or have a tamper evidence seal (not shown) to indicate if the apparatus 10 has been opened, moved, or otherwise disturbed.

For suitability with the rugged environs for which it is intended for use, the housing 100 and/or base 200 may be formed from impact resistant material such as Polycarbonate/Stainless Steel 316/304, preferably having a thickness of 2mm to 5mm thick, and more preferably having a thickness of 3mm to 4mm. In particular, the housing 100, base 200 (and its components) should be resistant to environmental and chemical conditions likely to be encountered on site.

The apparatus 10 may comprise fluid seals, preferably formed from closed cell materials, which may provide the apparatus 10 with good heat and chemical resistance.

It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

1. A device for a gas monitoring apparatus, comprising: a manifold having a plurality of sensor ports, each sensor port being configured to couple with an interchangeable sensor module, wherein the manifold is arranged to define a single gas flow path, such that a gas flowing through the manifold will flow via each sensor port; a gas inlet and a gas outlet, which are fluidly connected via a first valve and via the manifold; and a further gas inlet that is arranged to bypass the manifold to the gas outlet via a second valve and via a gas flow rate sensor.

2. A device according to claim 1, wherein the sensor ports are distributed in-line along the gas flow path, such that a gas will flow past each sensor port in turn.

3. A device according to any preceding claim, wherein the manifold comprises a first part, a second part and a gasket positioned between the first and second parts, wherein a plurality of channels are defined in the gasket to define the gas flow path between sensor ports.

4. A device according to claim 3, wherein the plurality of channels is provided in a sequential series, and wherein each channel extends between two sensor ports.

5. A device according to any preceding claim, wherein the manifold further comprises a single gas inlet and a single gas outlet, positioned one at each end of the gas flow path.

6. A device according to any preceding claim, wherein the manifold has a uniform cross-section

7. A device according to claim 6, wherein the manifold is generally circular.

8. A device according to any preceding claim, wherein the manifold further comprises a printed circuit board (PCB) arranged to interface with a coupled sensor module.

9. A device according to any preceding claim, further comprising a pump arranged to pump gas along the gas flow path.

10. A device according to any preceding claim, further comprising a plurality of interchangeable sensor modules, each arranged to couple with any one of the sensor ports.

11. A device according to any preceding claim, wherein the gas flow rate sensor is a differential pressure sensor.

12. An apparatus for gas monitoring, comprising a device according to any of claims 1 to 11.

13. An apparatus according to claim 12, further comprising a housing comprising a main body arranged to contain the device and a separate cover arranged to seal the device within the main body.

14. An apparatus according to claim 13, wherein the cover is arranged to retain one or more sensor modules within its respective sensor port.

15. An apparatus according to claim 13 or 14, further comprising tamper evidencing means arranged to indicate if the cover has been removed from the housing.

16. An apparatus according to any of claims 13 to 15, wherein the cover further comprises a gas inlet and/or a gas outlet arranged in fluid communication with the device.

17. An apparatus according to any of claims 13 to 16, wherein the cover further comprises a power source arranged to provide a power supply to the device.

18. An apparatus according to any of claims 13 to 17, wherein the cover comprises a radio module, arranged to transmit data obtained from a sensor housed in a sensor module coupled to a sensor port.

19. An apparatus according to any of claims 12 to 18, further comprising a gas inlet and a gas outlet, both respectively fluidly connected to the gas inlet and gas outlet of the device; wherein the gas inlet of the apparatus is provided underneath the main body.

20. An apparatus according to claim 19 when dependent on claim 11, wherein the apparatus further comprises a further gas inlet provided underneath the main body that is arranged to bypass the manifold to the gas outlet of the apparatus via the differential pressure sensor for detecting the pressure at the gas inlet of the apparatus.

21. An apparatus according to claim 19 or 20, further comprising a yet further inlet arranged to inlet atmospheric air into the apparatus.

22. An apparatus according to any of claims 19 to 21, wherein the gas outlet of the apparatus is arranged to vent to atmosphere.

23. An apparatus according to claim 22, further comprising a gas outlet valve arranged downstream of the manifold that is controllable to direct the route of the gas flow path either to the gas outlet of the apparatus arranged to vent to atmosphere or to a further gas outlet arranged to vent beneath the main body.

24. An apparatus according to any of claims 19 to 23, further comprising a gas safety valve arranged upstream of the manifold, the gas safety valve controllable to direct the gas flow path directly from the gas inlet of the apparatus to a gas outlet, thereby by-passing the manifold.

25. An apparatus of any of claims 12 to 24, wherein the first valve and the second valve are solenoid valves arranged to control gas flow through the apparatus.