Patent Description:
Gas detectors generally come in Intrinsically Safe (I. ) or explosion-proof versions. version of a gas detector usually has a different enclosure than an explosion-proof version because of the expenses associated with the latter. Having different enclosures for different gas detectors may cause an increase in the number of different parts needed, which in turn, may cause an increase in material, labor, and overall costs. <CIT> discloses a sensor module including a sensor module body, a sensing element within the sensor module body that senses a characteristic of the environment, a breathing element within the sensor module body that allows the sensing element to access the environment, electronics within the sensor module body coupled to the sensing element, and wherein the sensor module body forms a wall of a flame path.

Aspects of the disclosure relate to methods, apparatuses, and/or systems for intrinsically safe and explosion proof enclosure platforms for convertible gas detectors.

As described herein, a convertible gas detector is provided. The convertible gas detector comprises a gas sensor including a sensor circuit. The gas detector further comprises an enclosure configured to house the sensor circuit. The gas detector further comprises an end cap configured to be detachably connected to the enclosure along a flamepath joint. The gas detector is configured to switch between operating as an explosion proof detector, when the end cap is connected to the enclosure, and operating as an intrinsically safe detector, when the end cap is not connected to the enclosure.

The convertible gas detector may be configured such that responsive to connecting the end cap to the enclosure, the gas detector operates as an explosion-proof detector.

The sensor circuit may be intrinsically safe, and responsive to removing the end cap from the enclosure, the gas detector operates as an intrinsically safe gas detector.

The enclosure may comprise a bottom end, and the end cap may comprise a base element. The end cap may be configured to be detachably connected to the enclosure such that the base element interfaces with the bottom end of the enclosure to form a flameproof joint.

The enclosure may comprise a side wall having an inner wall and an outer wall, and the end cap may comprise a projecting element. The end cap may be configured to be detachably connected to the enclosure such that the projecting element interfaces with a portion of the outer wall to form a flameproof j oint.

The enclosure may comprise a side wall having an inner wall and an outer wall, and the end cap may comprise a projecting element. The end cap may be configured to be detachably connected to the enclosure such that the projecting element interfaces with a portion of the inner wall to form a flameproof j oint.

As described herein, a method for manufacturing a convertible gas detector is provided. The method comprises: providing a gas sensor, the gas sensor comprising a sensor circuit; providing an enclosure, the enclosure configured to house the sensor circuit; and providing an end cap, the end cap configured to be detachably connected to the enclosure along a flamepath joint, wherein the convertible gas detector is configured to switch between operating as an explosion proof detector, when the end cap is connected to the enclosure, and operating as an intrinsically safe detector, when the end cap is not connected to the enclosure.

Optionally, responsive to connecting the end cap to the enclosure, the convertible gas detector operates as an explosion-proof detector.

The sensor circuit may be intrinsically safe, and responsive to removing the end cap from the enclosure, the gas detector may operate as an intrinsically safe gas detector.

Optionally, the enclosure comprises a bottom end; the end cap comprises a base element; and the end cap is configured to be detachably connected to the enclosure such that the base element interfaces with the bottom end of the enclosure to form a flameproof j oint.

Optionally, the enclosure comprises a side wall, the side wall having an inner wall and an outer wall; the end cap comprises a projecting element; and the end cap is configured to be detachably connected to the enclosure such that the projecting element interfaces with a portion of the outer wall to form a flameproof j oint.

Optionally, the enclosure comprises a side wall, the side wall having an inner wall and an outer wall; the end cap comprises a projecting element; and the end cap is configured to be detachably connected to the enclosure such that the projecting element interfaces with a portion of the inner wall to form a flameproof j oint.

Various other aspects, features, and advantages of the invention will be apparent through the detailed description of the invention and the drawings attached hereto. It is also to be understood that both the foregoing general description and the following detailed description are examples and not restrictive of the scope of the invention.

Certain exemplary embodiments will now be described in greater detail by way of example only and with reference to the accompanying drawing in which:.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It will be appreciated, however, by those having skill in the art that the embodiments of the invention may be practiced without these specific details or with an equivalent arrangement. In other cases, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the embodiments of the invention.

The present disclosure, in accordance with some embodiments, describes enclosures for intrinsically safe and explosion proof convertible gas detectors. Generally, gas detectors use different protection techniques for safely operating in hazardous environments (e.g., when detecting explosive gases). For example, explosion-proof techniques generally use an enclosure configured to withstand and contain any explosion (e.g., caused by high temperature, spark, or malfunction) within the enclosure.

Another technique is the intrinsic safe protection technique. The intrinsic safe protection technique limits the energy used by the control circuits of the gas sensor to an energy level threshold. This may render the gas detector incapable of producing enough heat, spark, or any other ignition source to ignite an explosive environment. However, this gas detector configuration only works when the control circuits of the gas sensor are intrinsically safe. In other words, if the user changes the gas sensor, the new gas sensor needs to be intrinsically safe to operate with the gas detector. Otherwise, a different gas detector having an explosion-proof enclosure may be needed. This may be costly and challenging because it may increase the number of different parts for the different detectors (intrinsically safe detectors and explosion-proof detectors).

The present disclosure describes an intrinsically safe and explosion-proof enclosure platform for convertible gas detectors. In some embodiments, the same enclosure may be used, in different configurations, both intrinsically safe and explosion-proof gas detectors. This may provide a convertible gas detector that can be converted from an I. to an explosion-proof detector (or vice-versa) based on the configuration of the enclosure. For example, in some embodiments, an intrinsically safe (IS) gas detector, having an IS control board, may include an enclosure configured to receive a gas sensor (sensing interface and control board). In some embodiments, the IS gas detector may be converted to an explosion-proof detector by adding an end cap to the enclosure along the flamepaths. This may be advantageous because it may allow the user to switch gas sensors without having to change the whole gas detector (including the enclosure). For example, in cases where the user wants to detect a different gas with a different sensor that does not meet the IS requirement, the user may be able to use the same enclosure with the end cap configuration to make the gas detector explosion-proof and meet the operation safety requirements.

Similarly, in some embodiments, if the gas sensor of the explosion-proof detector is an IS sensor, or if the gas sensor is changed to an IS sensor (e.g., to detect a different gas), the explosion-proof gas detector may be converted to an IS gas detector by removing the cap of the enclosure. In these cases, the gas detector does not need the end cap of the enclosure to operate or to meet the operation safety requirements.

In some embodiments, the end cap may be operatively connected to the enclosure along a flamepath using one or more explosion-proof techniques. A flamepath may refer to a place where corresponding surfaces, of the enclosure and the end cap, come together to prevent the transmission of an internal explosion to the potentially explosive gas atmosphere around the enclosure. In some embodiments, the end cap and the enclosure connect at a flame-proof joint along the flamepath. The present disclosure describes examples of enclosures, end-caps, and flameproof-joints that can be used for convertible gas detectors herein below. However, these examples are for illustrative purposes only and are not intended to be limiting. Other enclosures, end caps, or joints may be used to accomplish a convertible gas detector and are consistent with the present disclosure.

<FIG> is a cross section view of an example of a convertible gas detector <NUM>, in accordance with one or more embodiments. In some embodiments, gas detector <NUM> may include a gas sensor <NUM>. In some embodiments, gas sensor <NUM> may be configured to detect (or measure) gas within a sensing chamber of the gas detector <NUM>. In some embodiments, gas sensor <NUM> may be an IS gas sensor having intrinsically safe designed control electronics.

Enclosure <NUM> may be configured to house one or more components of gas detector <NUM>. In some embodiments, gas sensor <NUM> may be housed in enclosure <NUM>. In some embodiments, gas sensor <NUM> may be detachably connected to enclosure <NUM> to facilitate removal of gas sensor <NUM> (e.g., for maintenance, repair, malfunction, or if gas detector <NUM> is used to detect a different gas). In some embodiments, enclosure <NUM> may include a side wall <NUM> and bottom end <NUM>. Side wall <NUM> includes an outer wall <NUM> and an inner wall <NUM>. In some embodiments, enclosure <NUM> may be configured to detachably connect with end cap <NUM> along a flamepath (as explained herein below). Enclosure <NUM> and end cap <NUM> may connect along a portion of outer wall <NUM>, inner wall <NUM>, or bottom end <NUM>. As explained below, enclosure <NUM> and end cap <NUM> may connect in different ways using explosion-proof techniques. For example, in some embodiments, enclosure <NUM> may include one or more threads <NUM> on a lower portion of outer wall <NUM> (towards bottom end <NUM>). In some embodiments, threads <NUM> may be configured to mate with one or more threads on end cap <NUM>.

End cap <NUM> may be configured to be removably connected to enclosure <NUM>. In some embodiments, end cap <NUM> is configured to interface with enclosure <NUM> along one or more flamepaths and provide a flameproof joint to prevent any potential explosion inside the enclosure from propagating to the outside of the enclosure. In some embodiments, in addition to the flameproof joint, end cap <NUM> may be affixed or attached to enclosure <NUM> at multiple points using multiple connecting means (e.g., bolts, screws, pins, etc.). In the example shown in <FIG> and <FIG>, end cap <NUM> includes a base element and a side wall <NUM>. Side wall <NUM> includes an outer wall <NUM> and an inner wall <NUM>. In some embodiments, end cap <NUM> may include threads <NUM> on an inner wall <NUM>. Threads <NUM> are configured to mate with threads <NUM> of enclosure <NUM>. Threaded joint <NUM>-<NUM> may provide a flameproof joint configured to prevent the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>. In some embodiments, end cap <NUM> may be removed from gas detector <NUM> if gas sensor <NUM> is an IS sensor. End cap <NUM> may be affixed to enclosure <NUM> to convert gas detector <NUM> to an explosion-proof detector (e.g., if gas sensor <NUM> is not an IS sensor, or simply for extra precaution).

As mentioned above, end cap <NUM> and enclosure <NUM> (or gas detector <NUM>) may be connected at different points in addition to the flamepath. The end cap may include one or more elements configured to interface with the enclosure (or with the gas detector) at these points of connection. For example, end cap <NUM> may include a lower end element <NUM>, protruding in the opposite direction of side wall <NUM>. Element <NUM> may be configured to interface with a weather shield <NUM> of gas detector <NUM>. This disclosure will focus on the connection of the end cap and the enclosure at the flameproof joints. The other connecting points may differ based on the enclosure, the gas detector, presence of weather shields, and the overall design of the gas detector.

<FIG> illustrate different examples of flameproof joints that can be used to connect the enclosure and the endcap of a convertible gas detector.

In some embodiments, as shown in <FIG>, enclosure <NUM> may include threads <NUM> on inner wall <NUM>. End cap <NUM> may include threads <NUM> on outer wall <NUM>. Threaded joint <NUM>-<NUM> may be configured to provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>. In some embodiments, flameproof threaded joint <NUM>-<NUM> may be a cylindrical threaded j oint configured such that threads <NUM> and <NUM> run parallel relative to its axis of revolution. In some embodiments, not shown in the figures, threaded joint <NUM>-<NUM> may be a tapered threaded joint configured such that the threads run parallel relative to the joint's axis of revolution.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof cylindrical joint having a constrained element that allows relative movement of two parts along a single axis. <FIG> shows an example of a cylindrical joint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> by pins <NUM> and such that inner wall <NUM> of side wall <NUM> and outer wall <NUM> of side wall <NUM> form a cylindrical joint <NUM>-<NUM>. Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. Cylindrical joint <NUM>-<NUM> may be configured to allow relative movement of the enclosure <NUM> and end cap <NUM> along a single axis; which may provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof flanged joint having flanges configured to fasten the enclosure and the end cap. <FIG> shows an example of a flanged joint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> by pins <NUM>. Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. In these cases, end cap <NUM> does not include a side wall, instead, end cap <NUM> is formed by base element <NUM>. A flanged joint is formed with a portion <NUM> of a top surface of base element <NUM> and a portion <NUM> of bottom end <NUM>. Flameproof flanged joint <NUM>-<NUM> may be configured to provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof spigot joint having two adjacent segments and one change of direction. <FIG> shows an example of a spigot joint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> by pins <NUM> and such that outer wall <NUM> of side wall <NUM> fits a slot formed on bottom end <NUM> along inner wall <NUM>. Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. A portion <NUM> of a top surface of base element <NUM> and a portion <NUM> of bottom end <NUM> are connected. Flameproof spigot joint formed by <NUM>-<NUM> and <NUM>-<NUM> may be configured to provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof conical joint configured such that the mating surfaces are conical and the gap normal to the mating surfaces is consistent across the entire surface. <FIG> shows an example of a conical joint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> (e.g., by pins <NUM>). Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. End cap <NUM> includes a conical projecting member <NUM> configured to mate with a corresponding surface on inner wall <NUM> of the enclosure to form a flameproof conical joint. The flameproof conical joint formed by the conical member <NUM> and corresponding surface provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof serrated joint having at least five fully engaged serrations. <FIG> shows an example of a serrated joint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> (e.g., by pins <NUM>). Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. End cap <NUM> includes serrations <NUM> on a top surface of base element <NUM> configured to mate with serrations <NUM> on bottom end <NUM> of the enclosure. The flameproof serrated joint <NUM>-<NUM> have at least <NUM> fully engaged serrations. Serrated joint <NUM>-<NUM> may be configured to provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

In some embodiments, the end cap may be affixed to the enclosure using a flameproof multistep joint having at least <NUM> adjacent segments where the flamepath changes direction at least <NUM> times by <NUM> degrees. <FIG> shows an example of a multistep j oint, according to one or more embodiments. In some embodiments, end cap <NUM> may be connected to enclosure <NUM> such that base element <NUM> of end cap <NUM> is affixed to bottom end <NUM> of enclosure <NUM> (e.g., by pins <NUM>). Pins <NUM>, in some embodiments, may be screws, bolts, or other connecting means. End cap <NUM> includes a projecting member <NUM> configured to mate with a corresponding surface on bottom end <NUM> of the enclosure to form a flameproof multi-step joint. The flameproof multi-step joint <NUM>-<NUM> formed by the member <NUM> and corresponding surface <NUM> includes at least <NUM> adjacent segments where the flamepath changes direction at least <NUM> times by <NUM> degrees. The flameproof multi-step joint is configured to provide a flamepath that prevents the transmission of an internal explosion to the explosive gas atmosphere around enclosure <NUM>.

It is to be noted that the above examples are for illustrative purposes only and is not intended to be limiting. It will be apparent to those skilled in the art in view of the present disclosure that other methods for removably connecting the end cap and the enclosure with a flameproof j oint may be used and are consistent with the present disclosure.

It should be understood that the description and the drawings are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claims. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description and the drawings are to be construed as illustrative only and are for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed or omitted, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the scope of the invention as described in the following claims. Headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description.

Claim 1:
A convertible gas detector (<NUM>) comprising:
a gas sensor (<NUM>), the gas sensor (<NUM>) comprising a sensor circuit;
an enclosure (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>), the enclosure configured to house the sensor circuit; and
an end cap (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>), the end cap configured to be detachably connected to the enclosure along a flamepath joint, characterised in that:
the gas detector (<NUM>) is configured to operate as an explosion proof detector when the end cap is connected to the enclosure, and is configured to operate as an intrinsically safe detector when the end cap is not connected to the enclosure.