Enclosure for a gas detector

Abstract

The present invention relates to an enclosure for a gas detector. In particular, a gas detector is provided and comprises a gas detector element, electronics interfacing with the gas detector element, and an enclosure configured to expose the gas detector element to the outside and to form an electronics housing region in which the electronics are arranged, whereby the electronics are isolated from the outside.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of provisional application No. 62 / 857,635 filed June 5, 2019, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The following description relates to gas detector enclosures, and more particularly to an enclosure for a non-dispersive infrared (NDIR) gas detector for low global warming potential (GWP) refrigerants. BACKGROUND

[0004] Typical refrigerated cargo containers, such as those used to transport cargo via sea, rail, or road, are containers that have been modified to include a refrigeration unit located at one end of the container. The refrigeration unit includes a compressor, a condenser, an expansion valve, and an evaporator. A volume of refrigerant is circulated throughout the refrigeration unit, and one or more evaporator fans of the refrigeration unit blow a supply air stream across the evaporator, cooling the supply air and forcing it out into the container.

[0005] In those cases where the refrigeration unit uses a refrigeration cycle to cool the supply air, a portion of the volume of the refrigerant tank can leak into the conditioned space. Since the refrigerant can be a low GWP refrigerant that is, for example, slightly flammable, the leakage of refrigerant into the conditioned space can pose a danger to the refrigerated cargo and to the personnel operating the refrigerated cargo container.

[0006] Accordingly, a gas detector is typically provided in the refrigerated cargo container or refrigeration unit in order to sense the presence of a gas due to a leak. Such a gas detector can include non-dispersive infrared (NDIR) technology and is used to determine the concentration of a particular gas in a given atmosphere. It is generally the case that the response time for these types of sensing elements is the duration of time required for the sensing element to accurately respond once a gas is introduced, and it is understood that the response time can be delayed if the environmental packaging of the electronics can trap the gas or un-contaminated air during the gaseous introduction to the sensing element. SUMMARY

[0007] According to aspects of the present disclosure, a gas detector is provided and includes a gas detector element, electronics interfacing with the gas detector element, and an enclosure configured to expose the gas detector element to an exterior and form an electronics housing region, the electronics being disposed in the electronics housing region whereby the electronics are isolated from the exterior.

[0008] According to further or alternative embodiments, the gas detector further includes a printed circuit board (PCB), and the PCB includes a first side and a second side opposite the first side, the gas detector elements are disposable on the first side, and the gas detector electronics are disposable on the second side.

[0009] According to further or alternative embodiments, the PCB includes a solid, unitary body configured to block fluid flow from the exterior to the electronics housing region.

[0010] According to further or alternative embodiments, the enclosure includes a body and a cover, wherein the PCB is securable to the body, and the cover is securable to the body over the PCB.

[0011] According to further or alternative embodiments, the cover defines an aperture through which the gas detector elements are exposed to the exterior, and the body cooperates with the PCB to form an electronics housing region in which the gas detector electronics are disposable.

[0012] According to further or alternative embodiments, the cover includes a cover portion and a spacer portion interposed between the PCB and the cover portion.

[0013] According to further or alternative embodiments, the spacer portion is thicker than the gas detector elements.

[0014] According to further or alternative embodiments, the spacer portion defines an opening that accommodates the gas detector elements, and includes a seal at the opening.

[0015] According to further or alternative embodiments, the gas detector elements and the gas detector electronics are disposable on the same side of the PCB.

[0016] According to further or alternative embodiments, the PCB defines a PCB aperture through which the gas detector elements are exposed to the exterior, and the PCB includes a solid, unitary body that surrounds the PCB aperture and is configured to block fluid flow from the exterior to the electronics housing region.

[0017] According to another aspect of the disclosure, a refrigeration system is provided and is configured to condition an interior volume of a conditioned space. The refrigeration system includes a gas detector that is disposed within the interior space.

[0018] According to another aspect of the disclosure, a gas detector is provided and includes a printed circuit board (PCB) and an enclosure. Gas detector elements and electronics interfacing with the gas detector elements can be disposed on the printed circuit board. The enclosure includes a body and a cover that can be attached together to substantially enclose the PCB. The cover defines an aperture through which the gas detector elements at a first side of the PCB are exposed to an exterior. The body cooperates with the PCB to define an electronics housing region in which the electronics at a second side of the PCB can be disposed. The electronics housing region is isolated from the exterior.

[0019] According to further or alternative embodiments, the PCB includes a solid, unitary body configured to block fluid flow from the exterior to the electronics housing region.

[0020] According to further or alternative embodiments, the PCB can be secured to the body and the cover can be secured to the body over the PCB.

[0021] According to further or alternative embodiments, the cover includes a cover portion and a spacer portion interposed between the PCB and the cover portion. The spacer portion is thicker than the gas detector elements, defines an opening that houses the gas detector elements, and includes a seal at the opening.

[0022] According to further or alternative embodiments, the gas detector elements and the electronics can be disposed on the same side of the PCB.

[0023] According to another aspect of the disclosure, a gas detector is provided and includes a printed circuit board (PCB) and an enclosure. The printed circuit board has a first side and a second side opposite the first side. Gas detector elements can be disposed on the first side and electronics interfacing with the gas detector elements can be disposed on the second side. The enclosure includes a body and a cover that can be attached together to substantially enclose the PCB. The cover defines an aperture through which the gas detector elements at the first side of the PCB are exposed to an exterior. The body cooperates with the PCB to define an electronics housing region in which the electronics at the second side of the PCB can be disposed. The electronics housing region is isolated from the exterior.

[0024] According to further or alternative embodiments, the PCB includes a solid, unitary body configured to block fluid flow from the exterior to the electronics housing region.

[0025] According to further or alternative embodiments, the PCB can be secured to the body and the cover can be secured to the body over the PCB.

[0026] According to further or alternative embodiments, the cover comprises a cover portion and a spacer portion interposed between the first side of the PCB and the cover portion. The spacer portion is thicker than the gas detector element, defines an opening that houses the gas detector element, and comprises a seal at the opening.

[0027] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] The sum of what is regarded as the subject matter of the present disclosure is specifically pointed out in the claims at the conclusion of the specification and is distinctly claimed. The foregoing and other features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a perspective view of a transport vehicle according to an embodiment;

[0030] Figure 2 is a perspective view of a transport vehicle according to an embodiment; Figure 1 is a schematic view of a refrigeration system of the transport vehicle of

[0031] Figure 3 is a side view of a gas detector according to an embodiment;

[0032] Figure 4 is a side view of a gas detector according to an embodiment; Figure 3 is an exploded side view of the gas detector of

[0033] Figure 5 is a side view of a gas detector according to an alternative embodiment.

[0034] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0035] As will be described below, an enclosure design is provided that isolates a gas detector diffusion membrane from electronic components that need to be protected within the enclosure. The enclosure design eliminates open space that can contain air and prevent gas from being introduced into the sensor, or open space that can contain flammable gas and prevent the sensor from identifying a safe environment. The enclosure design can significantly reduce the delay in response time (e.g., from about 20 minutes to 1 minute), and can allow an associated refrigeration system to create a safe warning or initiate a mitigation strategy at a faster pace. The enclosure design can also allow the associated refrigeration system to resume activity when the surrounding environment is deemed safe.

[0036] Referring to Figure 1 , a transport system 101 is shown, and includes a tractor or vehicle 102, a conditioned space 103 pulled by the vehicle 102, and a refrigeration system 104 that conditions the air within the conditioned space 103.

[0037] While the transport system 101 is described herein as a conditioned space 103 being pulled by a carrier 102, it will be appreciated that there are embodiments in which the conditioned space 103 is pulled by a railway, marine, or aerial transport, or can be provided within any suitable container, where the carrier 102 is a truck, train, ship, aircraft, helicopter, etc.

[0038] The carrier 102 can include a cab or driver's compartment 105 and a carrier motor 106. The carrier 102 can be driven by a driver located within the driver's compartment, driven remotely by a driver, driven autonomously, driven semi-autonomously, or any combination thereof. The carrier motor 106 can be an electric or combustion engine powered by a combustible fuel. The carrier motor 106 can also be part of a powertrain or drive system of a trailer system, such that the carrier motor 106 is configured to propel the wheels of the carrier 102 and / or the wheels of the conditioned space 103. The carrier motor 106 can be mechanically connected to the wheels of the carrier 102 and / or the wheels of the conditioned space 103.

[0039] The conditioned space 103 can be coupled to the carrier 102 and thus pulled or propelled to a desired destination. The conditioned space 102 can include a top wall 110, a bottom wall 111 opposite and spaced apart from the top wall 110, two side walls 112 spaced apart from and opposite each other, and opposite front and rear walls 113 and 114, where the front wall 113 is closest to the carrier 102. The conditioned space 103 can further include a door (not shown) at the rear wall 114 or any other wall. The top wall 110, the bottom wall 111, the side walls 112, and the front and rear walls 113 and 114 together define the boundaries of a refrigerated interior volume 115. The refrigeration system 104 is configured to condition the refrigerated interior volume 115.

[0040] With reference to Figure 2 The conditioned space 103 can be provided as an interior of a refrigerated trailer, a refrigerated truck, a refrigerated space, or a refrigerated container, where the refrigeration system 104 is adapted to operate using a refrigerant such as a low GWP refrigerant (such as A1, A2, A2L, A3, etc.). In some cases, the refrigerant can leak into the refrigerated interior volume 115, and can be hazardous if the concentration of the leaked refrigerant within the refrigerated interior volume 115 exceeds a threshold level. The threshold level can be the lower flammable limit of the refrigerant.

[0041] The evaporator 230, a portion of the refrigerant line 253 proximate the evaporator outlet 232, and a portion of the refrigerant line 250 proximate the evaporator inlet 231 can be located within the refrigerated interior volume 115 of the conditioned space 103, and thus can be a potential source of refrigerant leakage.

[0042] The refrigeration system 104 can be a transport refrigeration system, such as a transport refrigeration unit (TRU). The refrigeration system 104 includes a compressor 210, a condenser 220, an evaporator 230, and a leak detection system 240 including a leak sensor 242 in communication with a controller 241. The leak detection system 240 is arranged to detect and mitigate the presence of refrigerant within the refrigeration interior volume 115.

[0043] The compressor 210 is powered or driven by a power source 211. The compressor 210 receives a fluid flow of refrigerant from the evaporator 230 through a compressor inlet 212 and discharges the fluid flow of refrigerant to the condenser 220 through a receiver 221 through a compressor outlet 213. The condenser 220 receives the fluid flow of refrigerant from the compressor 210 through a condenser inlet 222 and discharges the fluid flow of refrigerant to the receiver 221 through a condenser outlet 223. The condenser inlet 222 is fluidly connected to the compressor outlet 213 through a refrigerant line 2201. A fan, such as a condenser fan 224, can be associated with and disposed proximate to the condenser 220.

[0044] The evaporator 230 is arranged to receive the fluid flow of refrigerant from the condenser 220 through an evaporator inlet 231 and to discharge the fluid flow of refrigerant to the compressor 210 through an evaporator outlet 232. The evaporator inlet 231 is fluidly connected to the condenser outlet 223 through the receiver 221, via a refrigerant line 250, through a first valve 251 and / or a second valve 252 disposed on an opposite side of the receiver 221 from the first valve 251. The evaporator outlet 232 is fluidly connected to the compressor inlet 212 through a refrigerant line 253. A fan, such as an evaporator fan 233, can be associated with and disposed proximate to the evaporator 230.

[0045] The first valve 251 can be an expansion valve, such as an electronic expansion valve, a movable valve, or a thermal expansion valve. The first valve 251 is movable between an open position and a closed position to selectively inhibit and promote fluid flow of refrigerant between the evaporator 230 and at least one of the condenser 220 and the receiver 221. The open position promotes fluid flow of refrigerant between the evaporator inlet 231 and the condenser outlet 223 through the receiver 221. The closed position inhibits fluid flow of refrigerant between the evaporator inlet 231 and the condenser outlet 223 through the receiver 221 and inhibits fluid flow of refrigerant between the receiver 221 and the evaporator inlet 231.

[0046] The receiver 221 is fluidly connected to the condenser 220 and the evaporator 230 and is arranged to receive and store refrigerant based on the position of at least one of the first valve 251 and / or the second valve 252. The receiver 221 is arranged to receive refrigerant from the condenser outlet 223 through the receiver inlet 2211 via the refrigerant line 250. In at least one embodiment, the second valve 252 is arranged to selectively facilitate fluid flow between the condenser outlet 223 and the receiver inlet 2211. The second valve 252 can be a movable valve, a solenoid valve, a liquid service valve, a thermal expansion valve, or an electronic expansion valve and can be moved between an open position and a closed position to facilitate or prevent fluid flow of refrigerant between the condenser outlet 223 and the first receiver inlet 2211. The receiver 221 is arranged to discharge or provide a fluid flow of refrigerant to the evaporator inlet 231 through the refrigerant line 250 via the first valve 251 through the receiver outlet 2212.

[0047] The third valve 254 can be arranged to selectively facilitate fluid flow between the compressor outlet 213 and the condenser inlet 222. The third valve 254 can be a movable valve, a check valve, a liquid service valve, a thermal expansion valve, or an electronic expansion valve and can be moved between an open and a closed position to facilitate or prevent fluid flow of refrigerant between the compressor outlet 213 and the condenser inlet 222.

[0048] The fourth valve 255 can be arranged to selectively facilitate fluid flow between the evaporator outlet 232 and the compressor inlet 212. The fourth valve 255 can be a movable valve, a check valve, a liquid service valve, a thermal expansion valve, or an electronic expansion valve and can be moved between an open and a closed position to facilitate or prevent fluid flow of refrigerant between the evaporator outlet 232 and the compressor inlet 212.

[0049] The leak detection system 240 includes a leak sensor 242 in communication with the controller 241. The leak sensor 242 can be disposed and configured to detect the presence or a selected amount or concentration of refrigerant and thus a refrigerant leak within the refrigerated interior volume 115 of the conditioned space 103.

[0050] The controller 241 is provided with input communication channels arranged to receive information, data, or signals from, for example, the compressor 210, the power supply 211, the condenser fan 224, the first valve 251, the evaporator fan 233, the second valve 252, the pressure sensor 243, the compressor discharge pressure sensor 244, and the leak sensor 242. The controller 241 is provided with output communication channels arranged to provide commands, signals, or data to, for example, the compressor 210, the power supply 211, the condenser fan 224, the first valve 251, the evaporator fan 233, and the second valve 252.

[0051] The controller 241 may include at least one processor, which is programmed to perform various operations based on information, data or signals provided via an input communication channel, including but not limited to leak detection and / or leak mitigation strategies, and to output commands via an output communication channel.

[0052] Leakage sensor 242 is arranged to provide a signal to controller 241 indicating the concentration, amount, or presence of refrigerant within the refrigerated internal volume 115 of the regulated space 103. Leakage sensor 242 may be located near evaporator 230 and / or near refrigerant line 250 or any other refrigerant line or component that may leak refrigerant into the regulated space 103. Leakage sensor 242 may also be located near a possible location where refrigerant may accumulate, such as near bottom wall 111.

[0053] Although the refrigeration system 104 has been described according to embodiments herein, it will be understood that other embodiments of the refrigeration system 104 and other regulating systems exist, and the following description relates to each of these embodiments and systems.

[0054] refer to Figure 3 and Figure 4 Gas detector 301 can be provided as Figure 2 The leak sensor 242. Gas detector 301 includes a gas detector element 310 and a gas detector electronics 320 that interfaces with the gas detector element 310. The gas detector electronics 320 can communicate with the gas detector element 310 and, in some cases, can be configured to receive signals from the gas detector element 310, process the signals into usable data, monitor the data, and take remedial measures if the signal from the gas detector element 310 exceeds a safety threshold. In other cases, the gas detector electronics 320 can be configured to control certain operations of the gas detector element 310. In any case, the gas detector electronics 320 can be configured to communicate with a controller 241. Gas detector 301 may further include a printed circuit board (PCB) 330 and a housing 340, on which the gas detector element 310 and the gas detector electronics 320 may be disposed. The enclosure 340 is configured to expose the gas detector element 310 to the outside (i.e., to the refrigerated internal volume 115, any gas or fluid therein, and particularly to any leaked refrigerant therein). The enclosure 340 is also configured to cooperate with the PCB 330 to form an electronics housing region 350. Gas detector electronics 320 may be disposed within the electronics housing region 350, thereby isolating the gas detector electronics 320 from the outside.

[0055] like Figure 3 and Figure 4As shown in FIG. 3, the PCB 330 includes a solid, unitary body 331 configured to prevent fluid flow from the exterior through the enclosure 340 and into the electronics housing region 350. The PCB 330 also includes a first side 332 and a second side 333 (see Figure 4 ). The gas detector element 310 can be disposed on the first side 332. The second side 333 is opposite the first side 332. The gas detector electronics 320 can be disposed on the second side 333.

[0056] The enclosure 340 includes a body 341 and a cover 342. The PCB 330 can be attached to the body 341, and the cover 342 can be attached to the body 341 over the PCB 330 such that the PCB 330 is substantially surrounded by the body 341 and the cover 342, with the first side 332 of the PCB 330 facing the cover 342 and the second side 333 of the PCB 330 facing the body 341. The cover 342 is formed to define an aperture 343 through which the gas detector element 310 is exposed to the exterior, and which can or can not have ribs or holes extending through the open space. The body 341 is formed to cooperate with the PCB 330 to define an electronics housing region 350 in which the gas detector electronics 320 can be disposed.

[0057] According to an embodiment, the body 341 includes a back plane 3410 facing the second side 333 of the PCB 330, and a sidewall 3411 connected to the second side 333 of the PCB 330 and positioning the back plane 3410 at a distance D from the second side 333 of the PCB 330. The electronics housing region 350 is thus bounded by the back plane 3410, the sidewall 3411, and the PCB 330. The distance D is sufficient to at least closely accommodate the gas detector electronics 320.

[0058] The cover 342 includes a cover portion 3421 and a spacer portion 3422, which can be separate members or integrally provided together in a single member, and which intervenes between the first side 332 of the PCB 330 and the cover portion 3421. The spacer portion 3422 is thicker than the gas detector element 310, formed to define an opening 3423 (see Figure 4 ) to accommodate the gas detector element 310, and in some cases can include a seal 3424 at the opening 3423. The opening 3423 is large enough to form a space around the gas detector element 310, with or without the seal 3424.

[0059] According to an alternative embodiment, and with reference to Figure 5In these or other cases, the PCB 330 defines a PCB aperture 501 through which the gas detector element 310 can be exposed to the exterior, and the PCB 330 includes a solid monolithic body 510 that surrounds the PCB aperture 501. Here, when the gas detector element 310 is exposed to the exterior through the PCB aperture 501, the connection or interface between the gas detector element 310 and the PCB 330 is sealed or otherwise impermeable such that the electronics housing region 350 is isolated from the exterior. Further, the solid monolithic body 510 that surrounds the PCB aperture 501 is configured to prevent fluid flow from the exterior to the electronics housing region 350 that does not pass through the PCB aperture 501.

[0060] Technical effects and benefits of the enclosure design of the present disclosure are to reduce response time (e.g., from about 20 minutes to 1 minute) and protect the electrical system from exposure to environmental influences such as humidity, dust, and other factors that can reduce reliability. The enclosure design will allow for the safety program to be initiated as quickly as possible compared to other designs. Additionally, the construction of the enclosure 340 is such that gases within the electronics housing region 350 can be trapped in the area in a conventional detector are isolated from the exterior of the enclosure 340 and minimized in size and internal volume. As such, few or no of the gases or other atmospheric features (i.e., air, moisture, debris, etc.) that can adversely affect sensor readings can become trapped in the electronics housing region 350.

[0061] While the present disclosure has been provided in some detail with respect to a limited number of embodiments, it should be appreciated that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can take many forms of variation, modification, substitution or equivalent arrangement not heretofore described without departing from the spirit and scope of the present disclosure. Furthermore, while various embodiments of the present disclosure have been described, it will be understood that example implementations can include only some of the described exemplary aspects. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

1. A gas detector for detecting a refrigerant leak in a space of a trailer, truck, or cargo container, the gas detector comprising: a gas detector element for detecting the refrigerant leak; electronics interfacing with the gas detector element; a printed circuit board (PCB) on which the gas detector element and the electronics are disposed; and an enclosure configured to expose the gas detector element to an exterior and the refrigerant leak and form an electronics housing region in which the electronics are disposed, whereby the electronics are isolated from the exterior and the refrigerant leak; wherein the enclosure includes a body to which the PCB is securable and a cover securable to the body over the PCB; wherein the cover includes a cover portion and a spacer portion interposed between the PCB and the cover portion, the spacer portion defining an opening, the cover defining an aperture, the gas detector element being exposed to the exterior through the opening and the aperture; wherein the PCB includes: a first side on which the gas detector element is disposable; and a second side opposite the first side on which the electronics are disposable.

2. The gas detector of claim 1, wherein, the PCB includes a solid, unitary body configured to block fluid flow from the exterior to the electronics housing region.

3. The gas detector of claim 1, wherein, the body cooperates with the PCB to form the electronics housing region in which the electronics are disposable.

4. The gas detector of claim 1, wherein, the spacer portion is thicker than the gas detector element.

5. The gas detector of claim 1, wherein, the spacer portion includes a seal at the opening.

6. A refrigeration system configured to condition an interior volume of a conditioned space, comprising the gas detector of any of claims 1-5, the gas detector being disposed within the interior volume.

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