Apparatus, system and method for gas leak detection

Abstract

The present invention is entitled "Device, System, and Method for Gas Leak Detection." Disclosed herein are methods, devices, and systems for monitoring gas leaks. An exemplary heating, ventilation, and air conditioning (HVAC) system may include: a sampling tube fluidly coupled to a first opening defined in a conduit; and a sensor assembly fluidly coupled to the sampling tube. The sampling tube is positioned exterior to the conduit and extends in the direction of gravity. The sensor assembly is configured to receive one or more gases having a greater density than ambient air and sense the one or more gases to generate a signal.

Description

Technical Field

[0001] The present disclosure relates generally to methods, systems, and associated sensor assemblies for monitoring gas leaks, and more particularly to sensor assemblies for monitoring and detecting refrigerant gas leaks. Background Art

[0002] Refrigeration units include refrigerant coils containing flammable refrigerant. Due to the flammability of refrigerant, leaks can be dangerous, and therefore leaks need to be detected before a sufficient amount of refrigerant leaks to create the potential for a fire or explosion. Through dedicated effort, ingenuity, and innovation, solutions have been developed, including in the embodiments of the present disclosure, to address many of these identified problems, and many examples of these solutions are described in detail herein.

[0003] The above exemplary invention contents and other exemplary objects and / or advantages of the present disclosure and the manner in which these objects and / or advantages are achieved are further explained in the following detailed description and the accompanying drawings. Summary of the Invention

[0004] According to various examples of the present disclosure, various exemplary methods, devices, and systems for monitoring gas leaks may be provided.

[0005] In some examples, a heating, ventilation, and air conditioning (HVAC) system may be provided. In some examples, the HVAC system may include: a sampling tube fluidly coupled to a first opening defined in a conduit; and a sensor assembly fluidly coupled to the sampling tube. In some examples, the sampling tube is positioned outside the conduit and extends in the direction of gravity. In some examples, the sensor assembly is configured to receive one or more gases having a greater density than ambient air and sense the one or more gases to generate a signal. In some examples, the sensor assembly includes a first opening configured to allow the one or more gases to diffuse through the first opening.

[0006] In some examples, the first opening includes a filter configured to screen dust and moisture from the one or more gases reaching the sensor assembly.

[0007] In some examples, the HVAC system may include a flush line. In some examples, the flush line includes a first end and a second end. In some examples, the flush line is fluidly coupled to the sensor assembly at the second end. In some examples, the flush line is fluidly coupled to the conduit at the first end. In some examples, the flush line is configured to receive one or more gases including ambient air from the refrigeration unit.

[0008] In some examples, the second end is positioned downstream of the first opening. In some examples, the HVAC system includes a drain pipe that is fluidly coupled to the sensor assembly. In some examples, the drain pipe is configured to allow one or more gases to flow from the sensor assembly. In some examples, the HVAC system includes a blower disposed within the duct unit, the blower being configured to periodically activate to blow ambient air into the flush tube.

[0009] In some examples, a sensor assembly may be provided. In some examples, the sensor assembly includes a chamber fluidly coupled to a sampling tube. In some examples, the chamber is configured to receive one or more gases from the sampling tube. In some examples, the chamber includes a second opening configured to allow the received one or more gases to flow through the second opening; and a gas sensor disposed within the chamber, the gas sensor configured to sense the one or more gases and generate a signal.

[0010] In some examples, the sensor assembly may include a flush tube fluidly coupled to the chamber, the flush tube configured to facilitate a flow of ambient air to the chamber to evacuate the one or more gases from the chamber, wherein when the flush tube is configured to receive one or more gases including ambient air from a conduit, the flush tube evacuates the one or more gases from the chamber and the gas sensor.

[0011] In some examples, the sensor assembly includes a drain fluidly coupled to the chamber. In some examples, the drain is configured to allow the one or more gases to escape therefrom upon receiving ambient air from the flush tube.

[0012] In some examples, the sensor assembly includes a first opening of the conduit. In some examples, the first opening has a filter. In some examples, the filter is configured to filter dust and moisture from the one or more gases reaching the chamber.

[0013] In some examples, the flush tube includes a plurality of heat exchange fins to reduce the temperature of the one or more gases reaching the chamber.

[0014] In some examples, the sensor assembly can include an air mover configured to move fluid through the sensor assembly.

[0015] In some examples, a catheter unit may be provided. In some examples, the catheter unit includes a catheter having a first opening oriented in the direction of gravity and a second opening complementary to the first opening and oriented in the direction of fluid flow. In some examples, the first opening is fluidically coupled to a sampling tube positioned externally of the catheter. In some examples, the second opening is fluidically coupled to an irrigation tube positioned externally of the catheter.

[0016] In some examples, the first opening includes a filter configured to screen dust and moisture from the one or more gases passing therethrough.

[0017] In some examples, the one or more gases include a refrigerant.

[0018] In some examples, the second opening is fluidly coupled to a flush tube. In some examples, the flush tube includes a bend and faces the blower to facilitate flow of one or more gases, the one or more gases including ambient air.

[0019] In some examples, the conduit unit can include a blower. In some examples, the blower can be configured to facilitate the flow of one or more gases to the irrigation tube. In some examples, the blower can be configured to activate at periodic time intervals.

[0020] The above exemplary invention contents and other exemplary objects and / or advantages of the present disclosure and the manner in which these objects and / or advantages are achieved are further explained in the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The description of the exemplary embodiments may be read in conjunction with the accompanying drawings. It should be understood that for simplicity and clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements. Embodiments incorporating the teachings of the present disclosure are shown and described with respect to the accompanying drawings set forth herein, in which:

[0022] Figure 1 An exemplary schematic diagram of a standard heating, ventilation, and air conditioning unit (HVAC) system is shown.

[0023] Figure 2 An exemplary schematic diagram of a catheter unit according to one or more embodiments of the present disclosure is shown.

[0024] Figure 3 An exemplary schematic diagram of a sensor assembly according to an exemplary embodiment of the present disclosure is shown.

[0025] Figure 4 An exemplary partial schematic diagram of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure is shown.

[0026] Figure 5 An exemplary cross-sectional view of a sensor assembly according to an exemplary embodiment of the present disclosure is shown.

[0027] Figure 6 An exemplary block diagram of a control unit according to an embodiment of the present disclosure is shown.

[0028] Figure 7 An exemplary flow chart of a method for operating an HVAC system used in accordance with an exemplary embodiment of the present disclosure is shown.

[0029] Figure 8 An exemplary schematic diagram of a catheter unit according to another embodiment of the present disclosure is shown.

[0030] Figure 9 An exemplary schematic diagram of a sensor assembly according to an embodiment of the present disclosure is shown.

[0031] Figure 10 An exemplary cross-sectional view of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure is shown.

[0032] Figure 11 An exemplary fluid flow diagram within a sensor assembly according to an embodiment of the present disclosure is shown.

[0033] Figure 12 An exemplary fluid flow diagram within a sensor assembly used in accordance with an exemplary embodiment of the present disclosure is shown.

[0034] Figure 13 An exemplary schematic diagram of a catheter used according to another exemplary embodiment of the present disclosure is shown.

[0035] Figure 14 An exemplary block diagram of an HVAC system configured in accordance with an exemplary embodiment of the present disclosure is shown.

[0036] Figure 15 A schematic diagram of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure is shown.

[0037] Figure 16 A schematic diagram of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure is shown.

[0038] Figure 17 The present invention is used to operate the Figure 14 An exemplary flow chart of a method for a sensor assembly.

[0039] Figure 18 FIG2 is a graph showing the voltage output of two oxygen sensors during changes in oxygen concentration levels.

[0040] Figure 19 FIG2 is a graph showing test results using an exemplary embodiment of the present disclosure, wherein butane is the target gas.

[0041] Figure 20 A block diagram of a sensor assembly with a flue configured according to an exemplary embodiment of the present disclosure.

[0042] Figure 21a An exemplary block diagram of a flue closure sensor assembly configured in accordance with an exemplary embodiment of the present disclosure is shown.

[0043] Figure 21b An exemplary block diagram of a sensor assembly configured according to an exemplary embodiment of the present disclosure is shown, wherein the flue extends outside the closed system.

[0044] Figure 22 An exemplary block diagram of a sensor assembly configured in accordance with an exemplary embodiment of the present disclosure is shown.

[0045] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0046] Some embodiments of the present disclosure will be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the present disclosure. In fact, these disclosures can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure meets applicable legal requirements. Throughout the content, similar reference numerals refer to similar elements. The terms used in this patent are not meant to be limiting, and the devices described herein or portions thereof may be attached or utilized in other orientations.

[0047] The phrases "in one embodiment," "according to one embodiment," "in some examples," etc. generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure, and may be included in more than one embodiment of the present disclosure (importantly, such phrases are not necessarily referring to the same embodiment).

[0048] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0049] If the specification states that a component or feature "may," "could," "would," "should," "will," "preferably," "likely," "typically," "optionally," "for example," "often," or "might" (or other such words) be included or have a characteristic, that particular component or feature is not required to be included or have that characteristic. Such components or features may optionally be included in some embodiments, or may be excluded.

[0050] Various embodiments discussed herein allow for monitoring and detecting gas leaks during operation, such as in heating, ventilation, and air conditioning (HVAC) units. In some examples, such refrigerants include safety-rated A2L refrigerants, such as, but not limited to, R-410A, R-1234yf, R-1234ze, R-32, R-454A, R-404A, R-454C, R-455A, R-447A, R-452B, and R-454B. A2L refrigerants / one or more refrigerant gases are more commonly used in such refrigeration units due to their lower global warming potential (GWP), and as a result, regulations have been enacted in many countries to monitor for leaks to avoid hazardous conditions during use. Although A2L refrigerants generally have low toxicity and are only mildly flammable, large leaks can still create hazardous conditions. Therefore, in some examples, monitoring and detecting such leaks is essential for refrigerant units.

[0051] Generally speaking, the vapor density of A2L refrigerant is greater than that of ambient air. Therefore, the refrigerant settles at the lowest point of the refrigeration unit under the action of gravity. Therefore, gas monitoring and detection must be performed at the lowest point of the refrigeration unit (in the direction of gravity).

[0052] Various exemplary embodiments of the present disclosure allow for a simple yet effective leak monitoring system. Additionally, the monitoring system may continuously receive output from the sensor to allow the monitoring system to provide a self-test function to verify whether the monitoring system is operable.

[0053] While various embodiments discuss refrigeration units, the various embodiments discussed herein can also be used for other types of gas leaks, such as HVAC applications using closed-loop cycles, fire suppression systems, and the like. For example, other such examples include, but are not limited to, inert gas leaks, natural gas leaks, propane gas leaks, butane gas leaks, carbon monoxide gas leaks, hydrocarbon gas leaks, and the like. The various embodiments discussed herein allow for the detection of large-scale leaks, such as gas leaks at or above approximately 1% volume / volume.

[0054] Figure 11 is an exemplary schematic diagram of a standard heating, ventilation, and air conditioning (HVAC) system 10. HVAC system 10 is an exemplary embodiment that may include or be associated with any of a variety of computing devices or sensing devices. HVAC system 10 includes a condenser unit 12 and an air handler or duct unit 14.

[0055] One of the condenser unit 12 and the duct unit 14 may include suitable logic and / or circuitry that may enable the condenser unit 12 to facilitate cooling and / or heating of the ambient air (flowing through the HVAC system 10). Figure 2 As shown, the condenser unit 12 may include a plurality of cooling / refrigeration pipes 16 that are fluidly coupled to a compressor (not shown). The compressor may flow one or more refrigerant gases through the plurality of cooling pipes. In some examples, a portion of the plurality of cooling pipes 16 may be positioned within the conduit unit 14. The conduit unit 14 may be configured to facilitate the flow of ambient air over the portion of the plurality of cooling pipes positioned within the conduit unit 14. The portion of the cooling pipes may facilitate cooling / heating of the ambient air. Figure 2 The structure of the catheter unit 14 is further described in .

[0056] Figure 2 A schematic diagram of a duct unit 14 according to one or more embodiments of the present invention is shown. The duct unit 14 includes a duct 20, a blower or fan 30, a control unit 40, and a sensor assembly 50. In some embodiments, the control unit 40 is communicatively coupled to the blower 30 and the sensor assembly 50.

[0057] The duct 20 has a duct inlet 22 and a duct outlet 24. The duct inlet 22 is configured to receive ambient air from the environment. In some embodiments, the duct inlet 22 can be fluidly coupled to additional ducts (not shown), each of which is configured to supply ambient air into the duct 20. Additionally or alternatively, the duct inlet 22 can be fluidly coupled to other components of the HVAC system 10 that are configured to supply ambient air to the duct 20. In an exemplary embodiment, the duct outlet 24 can be configured to provide conditioned air to the other components of the HVAC system 10. In some embodiments, the duct 20 can be defined by one or more walls that define a perimeter of the duct 20.

[0058] Figure 2 The conduit 20 includes at least a first wall 26 and a bottom plate 28. The first wall 26 extends parallel to a vertical axis 21 of the conduit unit 14. The vertical axis 21 is defined as being parallel to gravity 18. In some embodiments, the bottom plate 28 is coupled to the first wall 26 and extends perpendicular to the vertical axis 21.

[0059] The blower 30 can be positioned within the duct 20 to promote the flow of ambient air through the duct 20 and force the ambient air over the plurality of cooling / refrigeration ducts 16. The blower 30 has a blower opening 32 through which ambient air is forced, resulting in an airflow 34 through the duct 20. In some embodiments, the blower 30 can include suitable logic and / or circuitry (not shown) to control the speed and volume of the airflow 34. The blower 30 can have a blower opening 32 that faces the first end 228 of the flush tube 170. The blower 30 can be configured to be periodically activated to blow ambient gas into the flush tube 170.

[0060] In this embodiment, the blower 30 flushes the sensor assembly 50 each time the blower 30 operates. Continuously flushing the sensor assembly 50 after each operation of the blower 30 purges gas from the system and baselines the sensor assembly 50 to the same refrigerant gas level. This ensures that the refrigerant gas concentration sampled by the sensor assembly 50 is the same as the refrigerant gas concentration located within the conduit 20.

[0061] In another embodiment, the blower 30 may be connected to the sensor assembly 50. In this embodiment, the blower 30 is configured to generate an air flow through the sensor assembly 50 to flush the sensor assembly 50. The blower 30 of this embodiment may be located within the conduit 20 and mechanically coupled to the sensor assembly 50 and mounted as part of the sensor assembly 50. In this embodiment, activation of the blower 30 is initiated by a signal from the control unit 40.

[0062] In another embodiment, the blower 30 can be connected to the sensor assembly 50 and located outside of the conduit 20. In this embodiment, the blower 30 can be mechanically coupled to the sensor assembly 50 and can be mounted as part of the sensor assembly 50. The blower 30 of this embodiment is configured to generate an air flow through the sensor assembly 50.

[0063] The control unit 40 may include suitable logic and / or circuitry communicatively coupled to the blower 30 and the sensor assembly 50. In some embodiments, the control unit 40 may be coupled to the condenser unit 12. The control unit 40 may be coupled to the HVAC system 10 and configured to control the operation of the HVAC system 10. For example, the control unit 40 may be configured to activate / deactivate the blower 30, or otherwise control the blower 30 to adjust the speed and volume of the airflow 34 within the duct 20. The control unit 40 may be implemented as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). In some embodiments, the control unit 40 may include electronic, electromechanical, and mechanical technologies. Figure 6 The structure and operation of the control unit 40 are described.

[0064] In another embodiment, the control unit 40 is not configured to control the operation of the HVAC system. In this embodiment, the control unit 40 can be configured to control the airflow through the sensor assembly 50.

[0065] The sensor assembly 50 is coupled to the conduit 20 through the base plate opening 29 in the base plate 28. The sensor assembly 50 is positioned below the portion of the plurality of cooling channels 16 positioned within the conduit 20. In some embodiments, the sensor assembly 50 may be positioned directly below the portion of the plurality of cooling channels 16 positioned within the conduit 20. In other embodiments, the base plate 28 may include slots (not shown) or other structures to direct the flow of gas into the sensor assembly 50. In other embodiments, the sensor assembly 50 may include structures such as slots or funnels to be placed within the conduit to direct the flow of gas into the sensor assembly 50.

[0066] The sensor assembly 50 may be coupled to the control unit 40 and may be configured to provide a signal to the control unit 40 when the sensor assembly 50 detects a specific predefined gas. In an alternative embodiment, the sensor assembly 50 may be coupled to the control unit 40 and may be configured to provide a signal to the control unit 40 when the sensor assembly 50 does not detect the specific predefined gas.

[0067] Thus, the control unit 40 can be configured to monitor the signals received from the sensor assembly 50. Based on the monitoring of the signals from the sensor assembly 50, the control unit 40 can be configured to activate / deactivate the blower 30 or adjust the speed and volume of the airflow 34 through the duct 20 based on the signals from the sensor assembly 50. In another embodiment, the control unit 40 can be configured to automatically activate / deactivate the blower 30 without any intervention or correlation with the signals from the sensor assembly 50.

[0068] Figure 3 A schematic diagram of a sensor assembly 50 is shown, according to embodiments presented herein.

[0069] Figure 4 FIG2 shows a cross-sectional view of the sensor assembly 50 when a plane 80 cuts through the sensor assembly 50 according to one or more embodiments described herein. The sensor assembly 50 includes a first opening 52 and a second opening 54. The first opening 52 is coupled to a sampling tube 58. In an exemplary embodiment, the sampling tube 58 is received within a base plate opening 29 in the base plate 28 (e.g., FIG20 ). Figure 2 ). The sensor assembly 50 includes a first filter unit 60 located above the first opening 52 and a second filter unit 62 located above the second opening 54. In some examples, the first filter unit 60 can be configured to restrict dust particles and moisture from entering the sensor assembly 50.

[0070] The sensor assembly 50 defines a chamber 64 between the first opening 52 and the second opening 54. The chamber 64 is adjacent to a gas sensor 66. The gas sensor 66 is disposed adjacent to and connected to an electrical circuit 68. In some examples, the gas sensor 66 may be disposed within the chamber 64. In some examples, the gas sensor 66 is positioned along the first opening 52 or the sidewall 56 of the chamber 64. The gas sensor 66 may be embodied as a plurality of gas concentration sensors configured to detect the concentration of one or more gaseous fluids. In various embodiments, as discussed below, the gas concentration sensor may be an electrochemical sensor configured to monitor the concentration of one or more refrigerant gases.

[0071] The sensor assembly 50 may include a connection port 70. The connection port 70 may be a USB or other standard electrical connector. The connection port 70 may be used to connect to one of the control unit 40 or other devices used for data acquisition equipment.

[0072] Figure 5 A fluid flow diagram within the sensor assembly 50 is shown. During operation, one or more refrigerant gases 70 pass through the sampling tube 58 into the chamber 64 to reach the gas sensor 66. The gas sensor 66 detects the presence of the one or more refrigerant gases. Due to their higher vapor density, the one or more refrigerant gases may tend to move slowly within the sensor assembly 50 before exiting the second opening 54.

[0073] In some embodiments, the second filter 62 can be a check valve that restricts air from entering the gas sensor assembly from the environment surrounding the sensor assembly 50. The second filter 62 can include a structure that restricts the outflow of one or more refrigerant gases to allow the concentration of the one or more refrigerant gases to accumulate over time. In these embodiments, the second filter 62 can allow the one or more refrigerant gases to be exhausted from the sensor assembly 50 through the flow of ambient air, thereby creating a positive pressure generated by the activation of the blower 30.

[0074] In some examples, the scope of the present disclosure is not limited to a sensor assembly having a single sensor assembly or a sensor assembly having a single gas sensor coupled to a conduit. In an exemplary embodiment, multiple sensor assemblies 50 may be coupled to the conduit 20 without departing from the scope of the present disclosure. In another exemplary embodiment, the sensor assembly 50 may include multiple gas sensors 66. Furthermore, the scope of the present disclosure is not limited to sensing one or more refrigerant gases to determine leaks in multiple refrigeration coils. In an exemplary embodiment, the sensor assembly 50 may be configured to determine oxygen concentration to determine leaks of one or more refrigerant gases, such as Figures 14 to 22 Further described in .

[0075] In various embodiments, as discussed below, the gas sensor 66 can be an electrochemical sensor configured to monitor the concentration of one or more refrigerant gases, oxygen, or other gases that will be depleted as one or more gaseous fluids accumulate in the sensor. For example, one or more of these gas concentration sensors can be a fuel cell liquid electrolyte electrochemical sensor. In various embodiments, the gas concentration sensor can employ multiple electrodes, such as a sensing electrode, a reference electrode, and a counter electrode. The sensor also includes an electrolyte disposed above at least a portion of each electrode to form an ion path. One or more leads can be coupled to the electrodes on the sensing element via an electrical conductor, such as a wire. The leads can extend through the housing and be embedded within the housing. The sensor also includes a capillary / path that can be processed through a substrate to allow gas diffusion / transfer to the sensing electrode and / or electrolyte. The electrodes allow various reactions to occur to allow current or potential to develop in response to the presence of the target gas. The resulting signal can then allow the concentration of the target gas to be determined. Various sensors may be used in embodiments of the present disclosure, such as liquid electrolyte electrochemical sensors (e.g., consumable anodes (batteries) or fuel cell pumps), high temperature solid electrolyte electrochemical sensors (e.g., zirconium oxide or other oxygen ion conductors) and / or fluorescence quenching sensors (e.g., ruthenium-based dyes), optical sensors, non-dispersive infrared (NDIR) sensors, optical sensors, thermal sensors, semiconductor sensors, etc. Although the sensors discussed herein are referred to as gas concentration sensors, the sensing devices discussed herein may take the form of partial pressure sensors.

[0076] The circuitry 68 of the exemplary embodiment may also optionally include a communication interface, which may be any device, such as a device or circuit embodied in hardware or a combination of hardware and software, configured to receive data from and / or transmit data to other electronic devices that communicate with the sensor assembly (such as via near field communication (NFC) or other distance-based technology). Additionally or alternatively, the communication interface may be configured to communicate via a cellular protocol or other wireless protocol, including a Global System for Mobile Communications (GSM), such as but not limited to Long Term Evolution (LTE). In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and support hardware and / or software for implementing communications with a wireless communication network. Additionally or alternatively, the communication interface may include circuitry for interacting with one or more antennas to cause signals to be transmitted via the one or more antennas or to process signals received via the one or more antennas.

[0077] In various embodiments, at least a portion of the sensor assembly 50 may be disposed adjacent to a portion of the plurality of cooling ducts 16 within the HVAC system 10. For example, at least the sensor assembly 50 ( Figure 1) may be located near portions of the plurality of cooling ducts 16, and the circuit 68 may be located elsewhere.

[0078] In various embodiments, the sensor assembly 50 can be positioned close enough so that a leak of gas (e.g., refrigerant) can cause a change in oxygen concentration. In some embodiments, the sensor assembly 50 can be positioned near a portion of the plurality of cooling ducts 16 where leaks occur more frequently than at other locations. For example, gas leaks may more often occur at connections between different pipes. In various embodiments, the sensor assembly 50 can be positioned within the HVAC system 10, etc., so that any gas leaks can reach the sensor assembly 50.

[0079] Under passive conditions (no air flow through the sensor assembly 50), gases heavier than air flow through the openings in the base plate 28 and into the sampling tube 58 of the sensor assembly 50. The heavier-than-air gases accumulate in the chamber 64, near the gas sensor 66. This occurs regardless of whether the concentration in the sampling area subsequently changes due to leak cessation or remedial dilution, which will provide inaccurate sensor readings. Therefore, it is important to be able to flush the sensor assembly 50 without compromising the gas sensor's ability to receive and respond to leaking gas.

[0080] Figure 6 A block diagram 100 of the control unit 40 is shown, according to one or more embodiments described herein. The control unit 40 includes a processor 102 , a memory device 104 , an input / output (I / O) device interface unit 106 , and a flushing control unit 108 .

[0081] Processor 102 may be embodied as one or more microprocessors with one or more accompanying digital signal processors, one or more processors without accompanying digital signal processors, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuits, one or more computers, various other processing elements (including integrated circuits such as, for example, application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs)), or some combination thereof. Although in Figure 6102 is shown as a single processor, but in one embodiment, the processor 102 may include multiple processors and signal processing modules. The multiple processors may be implemented on a single electronic device or may be distributed across multiple electronic devices that are collectively configured to function as the circuitry of the HVAC system 10. The multiple processors may be in operable communication with each other and may be collectively configured to perform one or more functions of the circuitry of the HVAC system 10 as described herein. In an exemplary embodiment, the processor 102 may be configured to execute instructions stored in the memory device 104 or otherwise accessible to the processor 102. When executed by the processor 102, these instructions may cause the circuitry of the HVAC system 10 to perform one or more functions as described herein.

[0082] Whether the processor 102 is configured by hardware methods, firmware / software methods, or a combination thereof, the processor may include an entity capable of performing operations according to embodiments of the present disclosure while being configured accordingly. Thus, for example, when the processor 102 is embodied as an ASIC, FPGA, or the like, the processor 102 may include specially configured hardware for performing one or more operations described herein. Alternatively, as another example, when the processor 102 is embodied as an executor of instructions (such as may be stored in the memory device 104), these instructions may specifically configure the processor 102 to perform one or more algorithms and operations described herein.

[0083] Therefore, processor 102 used herein may refer to a programmable microprocessor, a microcomputer, or one or more multiprocessor chips that can be configured by software instructions (applications) to perform various functions including the functions of the various embodiments described above. In some devices, a plurality of processors dedicated to wireless communication functions and a processor dedicated to running other applications can be provided. Software applications can be stored in an internal memory before being accessed and loaded into the processor. The processor may include an internal memory sufficient to store application software instructions. In many devices, the internal memory can be a volatile or non-volatile memory such as a flash memory or a mixture of the two. The memory can also be located inside another computing resource (e.g., enabling computer-readable instructions to be downloaded via the Internet or another wired or wireless connection).

[0084] The memory device 104 may include suitable logic, circuitry, and / or interfaces adapted to store a set of instructions executable by the processor 102 to perform predetermined operations. Some commonly known memory implementations include, but are not limited to, a hard disk, random access memory, cache memory, read-only memory (ROM), erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM), flash memory, a magnetic cassette, a magnetic tape, a magnetic disk storage device or other magnetic storage device, a compact disk read-only memory (CD-ROM), a digital versatile disk read-only memory (DVD-ROM), an optical disk, a circuit configured to store information, or some combination thereof. In an exemplary embodiment, without departing from the scope of the present disclosure, the memory device 104 may be integrated with the processor 102 on a single chip.

[0085] The I / O device interface unit 106 may comprise suitable logic and / or circuitry that may be configured to communicate with the I / O device according to one or more device communication protocols such as, but not limited to, an I2C communication protocol, a serial peripheral interface (SPI) communication protocol, a serial communication protocol, a controller area network (CAN) communication protocol, and a serial communication protocol. The communication protocol communicates with one or more components of the HVAC system 10. In an exemplary embodiment, the I / O device interface unit 106 can communicate with the sensor assembly 50 and the blower 30. Some examples of the I / O device interface unit 106 can include, but are not limited to, a data acquisition (DAQ) card, an electric actuator driver circuit, and the like.

[0086] The irrigation control unit 108 may comprise suitable logic and / or circuitry that may be configured to monitor signals received from the sensor assembly 50, such as Figure 7 Further described in .

[0087] In an exemplary embodiment, the signal may indicate the concentration of gas accumulated within the sensor assembly 50. For example, the signal may indicate the concentration of one or more refrigerant gases accumulated within the sensor assembly 50. Based on the concentration of gas within the sensor assembly 50, the flush control unit 108 may be configured to activate / deactivate the blower 30, such as Figure 7 The flushing control unit 108 may be implemented as an ASIC or FPGA without departing from the scope of the present disclosure.

[0088] See also Figure 7 , which shows a flowchart 120 of a method for operating the HVAC system 10 according to the embodiments shown herein, at step 122, the HVAC system 10 includes means for activating the blower 30 to generate an airflow 34 of ambient air through the duct 20, such as the control unit 40, the processor 102, and the flushing control unit 108.

[0089] The plurality of cooling tubes 16 located within the duct 20 and coupled to the condenser unit 12 are configured to change the temperature of the ambient air. In some examples, one or more refrigerant gases may leak into the duct unit 14 due to leaks in the plurality of cooling tubes 16. Because the one or more refrigerant gases are heavier than the ambient air, the one or more refrigerant gases may fall from the plurality of cooling tubes 16 and accumulate along the bottom plate 28 or the bottom of the duct 20.

[0090] At step 124, the HVAC system 10 includes means for receiving a signal from the sensor assembly 50, such as the control unit 40, the processor 102, and the flushing control unit 108. The signal indicates the concentration of one or more refrigerant gases in the sensor assembly 50. In an exemplary embodiment, the processor 102 is configured to determine the concentration of the one or more refrigerant gases based on the received signal. In another exemplary embodiment, the sensor assembly 50 may be configured to generate a signal corresponding to the concentration of the one or more refrigerant gases in the sensor assembly 50.

[0091] At step 126, the HVAC system 10 includes means, such as the control unit 40, the processor 102, and the flush control unit 108, for comparing the determined gas concentration to a predetermined gas threshold. In an exemplary embodiment, the predetermined gas threshold may correspond to a threshold above which the concentration of one or more refrigerant gases is determined to be dangerous / harmful. In an exemplary embodiment, the predetermined gas threshold may be predefined during the manufacture of the HVAC system. If the flush control unit 108 determines that the concentration of one or more refrigerant gases is less than the predetermined gas threshold, the flush control unit 108 may be configured to repeat step 124. However, if the flush control unit 108 determines that the concentration of one or more refrigerant gases is greater than the predetermined gas threshold, the flush control unit 108 may be configured to generate a notification signal, as shown in step 128. The predetermined gas threshold may be a maximum threshold or a minimum threshold. The predetermined gas threshold may indicate the presence of one or more refrigerant gases or the absence of one or more non-refrigerant gases, such as oxygen.

[0092] At step 128, the HVAC system 10 includes means for generating a notification signal that the gas threshold has been exceeded, such as the control unit 40, the processor 102, and the flush control unit 108. In an exemplary embodiment, the notification may be transmitted to a user / operator of the HVAC to indicate that one or more refrigerant gases are leaking.

[0093] At step 130, the HVAC system 10 includes means for activating the blower 30, such as the control unit 40, the processor 102, and the flushing control unit 108. The blower 30 is set to operate for a predetermined amount of time. Once the blower is activated, the sensor assembly 50 will receive ambient air from the duct 20 to flush or remove the one or more refrigerant gases that have leaked from the sensor assembly 50. The ambient air may include a mixture of the one or more refrigerant gases that have leaked and air, or may simply include ambient air present in the duct 20.

[0094] After the blower 30 has been activated for a predetermined amount of time, step 124 will be repeated. The control unit 40 can be programmed to compare one or more signals from the sensor assembly 50 within a predetermined time frame and provide an alarm notification signal that the HVAC system 10 requires maintenance. The control unit 40 provides an alarm that refrigerant gas is present and triggers one or more signals to initiate preventative measures to reduce the possibility of a dangerous gas mixture accumulating within the duct 20.

[0095] In some embodiments, the alarm notification signal includes one of location information, gas concentration information, and sensor assembly failure information. In some embodiments, the alarm notification signal includes one of an audible signal and a visual signal. In some embodiments, the alarm notification signal may adjust the blower 30 to prevent one or more refrigerant gases from accumulating within the HVAC system 10.

[0096] During normal operation of the HVAC system 10, activation / operation of the blower 30 provides for periodic cleaning of the sensor assembly 50 by forcing ambient air through the sensor assembly 50. This periodic cleaning of the sensor assembly 50 prevents poisoning of the sensor assembly by continuously flushing ambient air through the sensor assembly and removing one or more refrigerant gases that may have leaked within the HVAC system 10. Additionally, this operation reduces the likelihood of false alarms due to the continued presence of one or more refrigerant gases.

[0097] Figure 8 A schematic diagram of a catheter unit 14 is shown in accordance with one or more embodiments of the present invention. Figure 8 The catheter unit 14 includes Figure 2 The duct 20 , blower 30 and control unit 40 , as well as the sensor assembly 150 are shown.

[0098] Sensor assembly 150 includes a sampling tube 158 and an irrigation tube 170. Sensor assembly 150 is fluidly coupled to catheter 20 via both sampling tube 158 and irrigation tube 170. Sampling tube 158 is fluidly coupled to catheter 20 via floor opening 29 in floor 28. Irrigation tube 170 is fluidly coupled to catheter 20 via wall opening 27 in first wall 26. In an exemplary embodiment, at least a portion of irrigation tube 170 may be positioned external to catheter 20.

[0099] In an exemplary embodiment, the irrigation tube 170 may include a first end 172, a second end 174, and a middle portion 176. The first end 172 of the irrigation tube 170 is fluidly coupled to the second opening of the sensor assembly 150. The second end 174 of the irrigation tube 170 may include an inner portion positioned within the interior of the conduit 20 and configured to collect the airflow 34 of the ambient air. In some examples, the second end 174 of the irrigation tube 170 may define a bend 178 that faces the second end 174 of the irrigation tube 170 in the direction of the airflow 34.

[0100] In some embodiments, the second end 174 of the flush tube 170 can be positioned facing the blower opening 32 of the blower 30. The blower 30 can be configured to be periodically activated to blow ambient gas into the flush tube 170.

[0101] Figure 9 A schematic diagram of a sensor assembly 150 according to embodiments described herein is shown. The sensor assembly 150 includes a first opening 152 and a second opening 154. The first opening 152 is coupled to the sampling tube 58, and the second opening 154 is coupled to the second end 174 of the flushing tube 170.

[0102] In an exemplary embodiment, the sampling tube includes a plurality of capillaries to allow one or more gases to diffuse therethrough.

[0103] Figure 10A cross-sectional view of sensor assembly 150 is shown with plane 180 cutting through it, according to one or more embodiments described herein. Sensor assembly 150 includes a first filter unit 160, a gas sensor 166, circuitry 168, and optionally a second filter unit (not shown). Gas sensor 166 is positioned atop circuitry 168. Gas sensor 166 is exposed to flushing tube 170 and sampling tube 158. Gas sensor 166 may be positioned perpendicular to the direction of one or more refrigerant gases entering gas sensor 166. In an exemplary embodiment, gas sensor 166 may be positioned parallel to the direction of outflow of one or more refrigerant gases. In an exemplary embodiment, first opening 152 includes first filter unit 160, and second opening 54 may include a second filter unit (not shown). The first and second filter units are configured to filter dust and moisture from the one or more gases reaching the sensor assembly. In some examples, sensor assembly 150 may define a chamber 164, wherein flushing tube 170 and sampling tube 158 are fluidically coupled to chamber 164. In some examples, gas sensor 166 is located within chamber 164 .

[0104] Figure 11 A fluid flow diagram within the sensor assembly 150 according to the embodiments described herein is shown. During operation, when the blower 30 is not activated, one or more refrigerant gases pass through the sampling tube 158 into the chamber 164 and reach the gas sensor 166, which detects the presence of the one or more refrigerant gases. Due to the higher vapor density, the one or more refrigerant gases may tend to accumulate within the sensor assembly 150.

[0105] Figure 12 A fluid flow diagram within the sensor assembly 150 according to the embodiments described herein is shown. During operation, when the blower 30 is activated, the flush tube 170 will receive ambient air from the conduit 20, which will be moved toward the chamber 164 under the influence of the blower. Due to the pressure of the ambient air in the flush tube 170, the flush tube 170 promotes the flow of ambient air toward the chamber, thereby purging the one or more refrigerant gases from the chamber. In addition, the pressure of the ambient air in the flush tube 170 also purges the one or more refrigerant gases from the chamber 164 and the gas sensor 504. This movement of the mixture of ambient air and residual one or more refrigerant gases will be well below the threshold, and the sensor assembly may not be affected by the residual one or more refrigerant gases. Thus, the possibility of poisoning the gas sensor 166 and / or reducing the variation in sensor reading inaccuracies is reduced.

[0106] In some examples, the scope of the present disclosure is not limited to the positioning of the irrigation tube 170 relative to the catheter 20. In an exemplary embodiment, the positioning of the irrigation tube 170 can vary based on the orientation of the catheter 20 without departing from the scope of the present disclosure. Figure 13 An example of this is shown in . Figure 13 In the illustrated embodiment of , both the sampling tube 158 and the flushing tube 170 are fluidly coupled to the bottom plate of the catheter 20 .

[0107] In another embodiment, the irrigation tube 170 may include heat exchange fins to cool the ambient air entering the sensor assembly 50 .

[0108] In an exemplary embodiment, the sampling tube includes a plurality of capillaries to allow one or more gases to diffuse therethrough.

[0109] It has been demonstrated that refrigerant gas can also leak through the wall and underneath the air handler unit. Another advantage is that the flushing action removes refrigerant from the flue and sensor, which also distributes fresh air around the sensor outlet. Thus, the flushing action dilutes the concentration of leaking refrigerant that has collected in that area, acting as a safety mitigation factor. This is Figure 13 , shown as the outlet on the right side of the sensor housing. In some embodiments, the flush tube 170 can extend substantially parallel to the horizontal axis 190 of the conduit 20. This advantage applies to any HVAC system with a confined space below a leak where gas can collect, concentrate, and cause explosion or fire issues over time.

[0110] In some examples, the scope of the present disclosure is not limited to coupling one sensor assembly to the conduit. In an exemplary embodiment, multiple sensor assemblies may be coupled to the conduit 20 without departing from the scope of the present disclosure. Furthermore, the scope of the present disclosure is not limited to sensing one or more refrigerant gases to determine leaks in multiple refrigeration coils. In an exemplary embodiment, the sensor assembly 150 may be configured to determine oxygen concentration to determine leaks of one or more refrigerant gases, such as Figures 14 to 22 Further described in .

[0111] Figure 14 FIG3 shows an HVAC 300 according to various embodiments of the present disclosure. As shown, the HVAC 300 may include one or more closed-loop gas (e.g., refrigerant) coils 310 and a sensor assembly 150. In various embodiments, at least a portion of the sensor assembly 150 may be disposed proximate to a given closed-loop gas coil 310 within the HVAC 300. For example, at least the sensor assembly 150 ( Figure 1 ) may be located near the closed-loop gas coil 310, and the circuitry may be located elsewhere.

[0112] In various embodiments, the sensor assembly 150 can be positioned close enough so that a leak of gas (e.g., refrigerant) can cause a change in oxygen concentration. In some embodiments, the sensor assembly 150 can be positioned near an area of ​​the closed-loop gas coil 310 where leaks occur more frequently than at other locations. For example, gas leaks may more often occur at connections between different tubing types. In various embodiments, the sensor assembly 150 can be positioned with the HVAC system 300, etc., so that any gas leaks can reach the sensor assembly 150.

[0113] Figure 15 is an exemplary configuration of a sensor assembly 500 according to another exemplary embodiment. As shown, a primary sensing device 520 and a reference sensing device 522 may be disposed within the sensor assembly 500. In various embodiments, the sensor assembly 500 may be oriented such that the coil surface 510 is proximate to the closed-loop gas coil 310, and in the event of such a leak, gas (e.g., refrigerant) leaks 515. Thus, the primary sensing device 520 and the reference sensing device 522 may be disposed in a common location, provided that the reference sensing device is exposed to ambient air via the flue extension. In some embodiments, there may be a performance trade-off between the leak location, gas movement, sensor location, sensitivity, and response time of the sensing devices. Response time is defined as the time it takes for a sensor to respond from no load to a step change in load.

[0114] In some embodiments, sensor assembly 500 can include a single sensor to allow positioning of the sensor away from gas leak 515. In some embodiments, sensor assembly 500 can include a single NDIR sensor.

[0115] In various embodiments, any gas leak 515 may reach the primary sensing device 520 before the reference sensing device 522. The primary sensing device 520 and the reference sensing device 522 are configured to determine the presence of one or more target gases (e.g., oxygen, carbon dioxide, refrigerant, or another gas). Thus, a first oxygen concentration level reading captured by the primary sensing device 520 may change (e.g., the oxygen concentration may decrease) due to a gas leak before a second oxygen concentration level reading captured by the reference sensing device 522 changes. Thus, in the event of a leak, the first oxygen concentration level reading may decrease more quickly than the second oxygen concentration level reading.

[0116] In some embodiments, the reference sensing device 522 may also be oriented differently from the primary sensing device 520 so that gas flowing from a potential leak site is prohibited from entering the reference sensing device 522 but not the primary sensing device 520 (e.g., Figure 15As shown by the arrows, the target gas can flow directly into the primary sensing device 520, but may have to travel around the circuit 530 and the flue extension to enter the reference sensing device 522. Thus, the temporal effects of the airflow can be more clearly shown by the output of each sensing device. In some embodiments, potential leak locations can be defined as areas susceptible to leaks. For example, in a refrigeration unit, potential leak locations may include protruding joints, connections between pipes, areas under mechanical and / or thermal stress, etc. In various embodiments, potential leak locations can be determined through testing for specific applications.

[0117] In some embodiments, the reference sensing device 522 may be exposed to the surrounding environment, such as ambient air outside the sensor assembly 500, via a flue extension coupled to the reference sensing device 522. In this regard, the reference sensing device 522 may not receive any target gas during a leak event. In such instances, the reference sensing device 522 may be located in an area having similar environmental conditions as the location of the primary sensing device 520. Although Figure 15 Only a single main sensing device 520 and a single reference sensing device 522 are shown, but various embodiments may use more than two sensing devices disposed on a single PCB and at the same location (ie, not spaced apart).

[0118] In various embodiments, at least a portion of the circuit 530 may be disposed within the sensor assembly 500. As shown, the primary sensing device 520 and / or the reference sensing device 522 may be connected to the circuit 530 via pins on the sensing devices configured to engage with sockets on the circuit 530. Various embodiments may employ different connection methods, such as solder pads configured on the sensing devices and pogo pins on the circuit 530. The various embodiments discussed herein may utilize any number of different standard electrical interconnects between the sensing devices and the circuit 530. In some embodiments, the primary sensing device 520 and / or the reference sensing device 522 may be equipped with short-range communication capabilities to allow the sensing devices to communicate remotely with the circuit 530. In various embodiments, the circuit 530 may be configured to receive oxygen concentration level readings from the primary sensing device 520 and the reference sensing device 522. In some embodiments, the circuit 530 may store one or more of the oxygen concentration level readings so that the oxygen concentration level readings can be monitored over time (e.g., over time, a first oxygen concentration level reading and a second oxygen concentration level reading may diverge due to a leak). In some embodiments, time series data can be used to determine leakage. In various embodiments, monitoring can be continuous. Alternatively, monitoring can be performed at intervals based on gas leak applications (e.g., some gas leaks may not be so dangerous, and intermittent monitoring may save costs).

[0119] Figure 16is another exemplary configuration of a sensor assembly 500 according to an exemplary embodiment. As shown, a primary sensing device 520 and a reference sensing device 522 may be disposed within the same sensor assembly 500. As shown, the primary sensing device 520 and the reference sensing device 522 may be disposed at the same location in a gas leak environment.

[0120] In some embodiments, the reference sensing device 522 can be equipped with a filter 524 configured to remove one or more target gases (e.g., refrigerant) from the gas entering the reference sensing device 522. In some embodiments, the filter 524 can be configured to absorb the one or more target gases (e.g., one or more refrigerant gases) passing therethrough. For example, the filter 524 can be an absorber. In some embodiments, the filter 524 can be positioned between the closed-loop gas coil 310 and the reference sensing device 522 such that any gas combination reaching the reference sensing device has passed through the filter 524 (e.g., removing some or all of the one or more refrigerant gases).

[0121] In various embodiments, filter 524 can be various types of activated carbon. In some such embodiments, the activated carbon can be impregnated with other chemicals, depending on the substance to be absorbed. In some embodiments, molecular sieves, zeolites, and / or other well-known filter systems can be used. In some embodiments, the target gas can determine the design of filter 524 (for example, Sofnocarb powder can be used in cases where butane is the target gas). In some embodiments, filter 524 can be designed to permanently absorb the target gas or slow its passage through the reference sensing device, resulting in a time difference in response compared to the primary sensing device.

[0122] In some embodiments, the primary sensing device 520 and the reference sensing device 522 can be a single sensor with multiple gas inlets. For example, the single sensor can have a primary sensing device gas inlet without a filter 524 and a reference sensing device gas inlet that can have a filter 524. In such embodiments, the sensing device can have a mechanical switch configured to switch access to the sensing electrode from the primary sensing device gas inlet to the reference sensing device gas inlet during operation. In such embodiments, various pumping devices can be used to move gas from the gas inlet to the sensing electrode. During operation, the mechanical switch can switch between the primary sensing device gas inlet and the reference sensing device gas inlet, and the difference between the first oxygen level reading and the second oxygen level reading from the primary sensing device gas inlet can be compared using a dual sensing device system as described herein.

[0123] In some embodiments, when a gas (e.g., refrigerant) leaks, the first oxygen concentration level reading of the primary sensing device 520 may begin to decrease, while the second oxygen concentration level reading of the reference sensing device 522 remains approximately constant (or at least decreases more slowly). In some cases where the gas leak is large enough, the filter 524 may become overloaded (e.g., completely saturated) at a certain point, causing the second oxygen concentration level reading of the reference sensing device 522 to begin decreasing in line with a sensing device without a filter. In such embodiments, a time lag between the decrease in the first oxygen concentration level and the decrease in the second oxygen concentration level may indicate the occurrence of a gas leak. Additionally, various other information may be determined via the various outputs of the sensing devices.

[0124] In various embodiments, at least a portion of the circuit 530 can be disposed within the sensor assembly 500 as a primary sensing device 520 and a reference sensing device 522. As shown, the primary sensing device 520 and / or the reference sensing device 522 can be connected to the circuit 530 via pins on the sensing devices configured to engage with sockets on the circuit 530. Various embodiments can employ different connection methods, such as solder pads configured on the sensing devices and pogo pins on the circuit 530. The various embodiments discussed herein can have any number of different standard electrical interconnects between the sensing devices and the circuit 530. In some embodiments, the primary sensing device 520 and / or the reference sensing device 522 can be equipped with short-range communication capabilities to allow the sensing devices to communicate remotely with the circuit 530. In various embodiments, the circuit 530 can be configured to receive oxygen concentration level readings from the primary sensing device 520 and the reference sensing device 522. In some embodiments, circuitry 530 can store one or more of the oxygen concentration level readings so that the oxygen concentration level readings can be monitored over time (e.g., over time, a first oxygen concentration level reading and a second oxygen concentration level reading can differ due to a leak). In various embodiments, monitoring can be continuous. Alternatively, monitoring can be performed at intervals based on gas leak application (e.g., some gas leaks may not be that dangerous, and intermittent monitoring may save costs).

[0125] Now see Figure 17 , an exemplary embodiment of the present disclosure includes a flow chart 600 of monitoring and detecting gas (e.g., refrigerant) leaks, including circuitry 530, a processor 532, a sensing assembly 500, and the like. Although various embodiments of the sensing assembly may include at least one processor 532, various embodiments of the sensing assembly may be analog systems such that the primary sensing device 520 and the reference sensing device 522 may communicate with differential and / or ratiometric amplifiers and use comparators to determine if a leak has occurred. Thus, Figure 17 The operations can be performed by the simulation system.

[0126] Now see Figure 17 At block 610, the sensing assembly 500 (such as the circuitry 530, the processor 532, etc.) may include means for receiving a first oxygen concentration level reading for a given area. In various embodiments, the first oxygen concentration level reading may be captured by the primary sensing device 520, as described above. In various embodiments, the first oxygen concentration level reading may be affected by environmental conditions, such as temperature. Additionally, in some embodiments, the first oxygen concentration level reading may be affected by the introduction of new gas (e.g., such as a gas leak that causes a decrease in oxygen concentration).

[0127] Now see Figure 17 At block 620, the sensing assembly 500 (such as the circuitry 530, the processor 532, etc.) may include means for receiving a second oxygen concentration level reading for a given area. In various embodiments, as described above, the first oxygen concentration level reading may be captured by the reference sensing device 522. In various embodiments, the reference sensing device 522 may be positioned under similar environmental conditions such that the effect of the environmental conditions on the second oxygen concentration level reading may be similar or identical to the effect of the environmental conditions on the first oxygen concentration level reading.

[0128] However, in various embodiments, the reference sensing device 522 can be configured such that the effect of the gas leak 515 on the second oxygen concentration level reading from the reference sensing device 522 can be different from the effect on the first oxygen concentration level reading from the main sensing device 520. For example, in the case where the reference sensing device 522 is coupled to a flue, the flue does not allow the leaked gas to pass through and reach the reference sensing device. The second oxygen concentration level reading can begin to decrease some time after the first oxygen concentration level reading begins to decrease because the gas (e.g., refrigerant) can take longer to reach the reference sensing device 522. Alternatively, in the case where the reference sensing device 522 is equipped with a filter 524 (e.g., Figure 16 ) or flue, the second oxygen concentration level may not be reduced by the gas leakage, while the first oxygen concentration level may be reduced by the gas leakage.

[0129] Now see Figure 5At block 630, the sensing assembly 500 (such as the circuitry 530, the processor 532, etc.) may include means for comparing the first oxygen concentration level reading and the second oxygen concentration level reading. In various embodiments, the difference between the first oxygen concentration level reading and the second oxygen concentration level reading may be correlated to the amount of gas leakage. In some embodiments, the comparison may be performed at a given time (e.g., when the primary sensing device 520 has a lower oxygen concentration level reading than the reference sensing device 522). In some embodiments, the first oxygen concentration level reading and the second oxygen concentration level reading may be monitored over time, such that changes in the first oxygen concentration level reading and the second oxygen concentration level reading may indicate the occurrence of a gas leakage.

[0130] In an exemplary analog embodiment, the main sensing device 520 and the reference sensing device 522 can measure the output current, which is converted to a voltage. Each output voltage can be amplified to eliminate any noise. Thus, the voltages can be compared using a differential or ratio. In such an analog embodiment, a comparator can be used to determine that a leakage has occurred.

[0131] Now see Figure 17 At block 640 , the sensing assembly 500 (such as the circuitry 530 , the processor 532 , etc.) may include means for causing transmission of a signal indicating a gas (e.g., refrigerant) leak if the difference between the first oxygen concentration level reading and the second oxygen concentration level reading is greater than a threshold difference.

[0132] In various embodiments, a possible gas leak can be determined based on a comparison of a first oxygen concentration level reading and a second oxygen concentration level reading. In some embodiments, the amount of target gas (e.g., refrigerant) allowed to leak can be based on the flammability of the gas. Therefore, the threshold difference can be below the flammability level of the target gas. For example, in the case of a flammability level of 10%, the threshold difference can be 1%. For example, a 1% change in oxygen concentration (e.g., from 20.9% oxygen concentration to 20.7% oxygen concentration) can indicate a 1% leak in the concentration of the gas (e.g., refrigerant). In various embodiments, the difference between the first oxygen concentration level reading and the second oxygen concentration level reading can be correlated with changes in oxygen concentration (e.g., primary sensing device 20 and reference sensing device 22 can be configured so that only the introduction of the target gas (e.g., a gas leak) can cause the first oxygen concentration level reading and the second oxygen concentration level reading to differ significantly). In various embodiments, the threshold difference can be between approximately 5% and 10% of the volume of the oxygen concentration level.

[0133] Figure 18Graph showing similar oxygen concentration readings of two sensors (such as the oxygen sensors used in various embodiments herein) during changes in oxygen levels in air. As shown, two sensors being exposed to the same air show almost identical readings and therefore can be relied upon to show significant changes in oxygen levels. The S2 / S1 line shown is the ratio of sensor 2 reading to sensor 1 reading. As shown, the ratio is approximately 1, and therefore any change in one of the sensor readings (e.g., in the event of a gas leak and primary sensing device 520 experiencing oxygen reduction before reference sensing device 522) can be represented by a change in the ratio from approximately 1.

[0134] Figure 19 shows a sensor assembly (similar to Figure 16 The output of the sensor assembly shown in FIG5 ) wherein the reference sensing device 522 is equipped with a flue and a filter 524. Figure 19 In the graph shown, the target gas is butane. As shown, the target gas is intermittently introduced into the sensor assembly, and each time the target gas is introduced, the primary sensing device 520 experiences a spike (e.g., spikes 700A-700D) above the nominal voltage, while the voltage of the reference sensing device 522 remains approximately constant due to the flue not allowing the gas to pass through it or the filter absorbing the butane. In the example shown, the differential is used to illustrate the occurrence of a leak, which is shown as spikes 710A-710D.

[0135] Figure 20 Shows something like Figure 16 , except that a flue 800 mounted on one side of the reference sensing device 522 is introduced. The flue 800 enables the reference sensing device to be exposed to fresh air and away from the leakage environment 810 or the area with leaking gas. On the other hand, the main sensing device 520 is exposed to a serious A2L gas leak. In this regard, a differential signal can be calculated based on the exposure of the leaking gas to the main sensing device 520 and the exposure of the ambient air to the reference sensing device 522. To this end, the flue 800 allows the ambient air to diffuse or pass through and keeps the reference sensing device 522 away from the leaking gas. In this regard, the efficiency of gas detection can be significantly enhanced based on the detection of changes in gas concentration in the working environment.

[0136] In one exemplary embodiment, a primary sensing device 520 and a reference sensing device 522 are co-located to detect A2L gas leaks in an AC system. This differential sensor system offers long life, self-calibration capabilities, and high reliability. The sensors are programmed to detect gas concentrations after a predetermined time and perform comparisons based on the detected concentrations. In this regard, the gas detection system recalibrates thresholds based on changes in ambient air (or oxygen) concentrations. Furthermore, the system is highly reliable because both the primary sensing device 520 and the reference sensing device 522 are co-located, exposing them to the same environmental variables, such as temperature, pressure, and humidity, with varying gas exposures. Consequently, the detector system detects even small changes in gas concentration, as described by the differential signal.

[0137] In another embodiment, two oxygen sensors are used to measure the decrease in oxygen concentration caused by an A2L gas leak. In the absence of a leak, both sensors are exposed to ambient air, resulting in a zero differential signal. However, to detect an A2L leak in the environment, a primary sensing device 520 is exposed to an area with leaking gas to detect changes in oxygen concentration. Simultaneously, a reference sensing device 522, attached to the flue 800, detects the oxygen concentration present in the ambient air. Each time the primary sensing device 520 detects a change in oxygen concentration, it compares it with the oxygen concentration in the ambient air. The control circuit receives signals from the primary sensing device 520 and the reference sensing device 522 and compares them to determine a differential signal. This differential signal thus indicates the change in oxygen concentration, or in other words, the concentration of A2L gas in the environment. For example, a 1% change in oxygen concentration (e.g., from 20.9% oxygen concentration to 20.7% oxygen concentration) can indicate that the gas detection system can accurately detect a 1% leaked gas (e.g., refrigerant) concentration.

[0138] In another exemplary embodiment, the flue 800 includes a filter (not shown) mounted at the inlet of the flue 800 to prevent A2L from passing through the flue 800. This results in increased sensitivity as the reference sensing device 522 detects the concentration of ambient air after filtering the A2L gas.

[0139] In another exemplary embodiment, the gas detector system includes two oxygen sensors, both configured to operate in an AC system. Sensor 1 is a primary sensing device 520 that detects oxygen depletion by exposure to one or more refrigerant gases (e.g., A2L). Additionally, sensor 2 is a reference sensing device 522 equipped with a flue 800 extending to clean air (absence of one or more refrigerant gases for approximately >10 minutes). The two sensors work in conjunction to generate a steady-state differential signal.

[0140] In another exemplary embodiment, the gas detector system is designed to be immune to potential false alarms caused by changes in temperature, pressure, and humidity. Unlike conventional dual oxygen sensor systems, the gas detector of the present invention does not trigger false alarms. Conventional oxygen sensors operate to detect the concentration of oxygen in the environment and trigger an alarm when the detected concentration level exceeds a predetermined level, without the need to calculate relative oxygen concentration. Relative oxygen concentration is calculated by comparing the sensed oxygen concentration to a reference threshold. The reference threshold is calibrated based on the prevailing ambient oxygen concentration.

[0141] In another exemplary embodiment, the recalibration of the predetermined threshold value is referred to as a continuous self-check reading of the O2 level. In this regard, any type of O2 dilution with heavy gases is detected, making the system adaptable to different gases.

[0142] In another exemplary embodiment, two sensors are positioned close to each other, resulting in a compact design, thereby co-locating the reference sensing device and all electrical devices, thereby minimizing unit size and maximizing compensation performance. By having a compact configuration, errors or losses due to electrical losses are minimized, resulting in a highly accurate and sensitive signal output.

[0143] In another exemplary embodiment, when the leak rate is high, the dual sensors are positioned at the bottom of the cabinet, and the leak occurs at the top of the flue. The flue has a cylindrical shape with a cross-section having an inner diameter of approximately 0.625 inches (0.0158m) and a height of approximately 6 inches (0.152m). Reference sensing device 522 is exposed to the air at the top of the cabinet. The differential output is the difference between the main sensing device 520 and the reference sensing device 522 with the flue 800.

[0144] In another exemplary embodiment, the reference sensing device 522 can compensate for temperature, pressure, and humidity changes. One advantage is that any effects of other ambient gases (such as CO2) on the sensor can be compensated to provide a more accurate reading. This is particularly useful in the case of an oxygen sensor, but it also applies to other sensor technologies and interferences.

[0145] Furthermore, from a system design perspective, the design of the flue 800 is universal. In this regard, flues 800 of different heights and diameters can be used without disrupting the mean free path of the target gas.

[0146] In another exemplary embodiment, the flue is a passive element and can be easily integrated into an existing system of reference sensors. In addition, there is no pump associated with the sensing system to push ambient air into the reference sensing device 522.

[0147] In another exemplary embodiment, the gas collection system has multiple flues leading to the sensor from various locations. The multiple flues enable multiple sensing locations within the air handler unit, providing a safety factor for HVAC manufacturers to ensure that leak detection is not affected by the sensor location.

[0148] Figure 21a A block diagram of a flue 900 enclosed sensor assembly configured in accordance with an exemplary embodiment of the present disclosure is shown. In this regard, the sensor system is placed within the furnace near the metering device. The primary sensing device 520 is exposed to the conditions within the furnace or other enclosed area 902, and the reference sensing device is modified using the flue 900, which can be extended away from the potential source of the leak. In this manner, the flue 900 can be adjusted to a maximum height within the furnace, or can be extended outside the furnace containment, such as Figure 21b shown.

[0149] See also Figure 21b , discloses a block diagram of a sensor assembly wherein a flue 904 extends outside a closed system 906. Figure 21a and Figure 21b In both configurations, a chimney 904 extending away from the area with the leaking gas is configured to provide ambient air to the reference sensing device 522 .

[0150] Figure 22 FIG. 1 is a block diagram of a sensing assembly configured according to an exemplary embodiment of the present disclosure. Figure 22 As shown, in order to determine the oxygen concentration, one end of the flue 910 is connected to the main sensing device 520, and the second end reaches the gas leakage environment. In this regard, the gas detector can detect gas leaks by exposing the main sensing device 520 to the leakage environment via the flue 910, and the reference sensing device is suitable for exposure to ambient air. In an exemplary embodiment, the flue can have any shape or size as required, and the size of the flue 910 is such that it allows gas to diffuse or pass freely without obstructing the mean free path of the gas. In this regard, the gas detector can be placed outside a cabinet, furnace or container without affecting the sensing quality of the gas detector. Due to the arrangement of the main sensing device and the reference sensing device on the printed circuit board (PCB), this arrangement helps to extend the service life of the sensor and improve sensitivity.

[0151] In another exemplary embodiment, the signal sensor is modified using a flue and is exposed to conditions inside the furnace by extending the flue to the location of one or more refrigerant gas leaks in the vessel or furnace. Thus, the reference sensor is open to conditions outside the furnace containment and is not affected by the refrigerant leak.

[0152] In another exemplary embodiment of the present invention, by placing the primary and reference sensing devices close to each other, signal delays caused by electronic circuitry or signal loss during transmission can be largely eliminated. Consequently, with this structural arrangement, the signal-to-noise ratio can be improved compared to conventional differential sensors, thereby improving response time. In this way, by minimizing delays caused by structural constraints (such as the relative placement of the primary and reference sensing devices) or by transmission or electronic circuitry, the sensitivity of the gas detector can be increased several times.

[0153] Furthermore, according to some exemplary embodiments, a sensor assembly for determining a composition of one or more gases includes: a main sensing device and a reference sensing device located proximate to the main sensing device; a flue coupled to the reference sensing device at one end thereof, wherein the reference sensing device is configured to determine a first oxygen concentration level of a given area via the flue, and wherein the main sensing device is configured to determine a second oxygen concentration level of the given area.

[0154] According to some exemplary embodiments described herein, a control circuit (which is electrically coupled to a primary sensing device and a reference sensing device) is configured to: receive determined first and second oxygen concentration levels from the primary sensing device and the reference sensing device; compare the first and second oxygen concentration levels; and, based on the comparison, cause a transmission that a gas leak has occurred if a difference between the second and first oxygen concentration levels is greater than a threshold difference.

[0155] Furthermore, according to some exemplary embodiments, the primary sensing device and the reference sensing device are located within the sensor assembly and are exposed to the same environmental variable.

[0156] Furthermore, according to some exemplary embodiments, the gas detector further includes a filter positioned on a side of the flue, wherein the filter is configured to screen out one or more gases from reaching the reference sensing device.

[0157] Furthermore, according to some exemplary embodiments, the primary sensing device is adapted to be exposed to a potential leak source, and the reference sensing device is adapted to be exposed to an environment other than the potential leak source under the same environmental variables.

[0158] Furthermore, according to some exemplary embodiments, the threshold difference is based on an oxygen concentration level between 5% and 10% by volume. To this end, the threshold difference is based on a flammability level of the gas. Furthermore, the target gas is a refrigerant gas.

[0159] Furthermore, according to some exemplary embodiments, the sensor assembly is further configured to receive one or more environmental variables and to correct the first oxygen concentration level reading and the second oxygen concentration level reading based on the environmental variables. The control circuitry includes at least one processor having computer-coded instructions therein, wherein the computer instructions, when executed, are configured to cause operation of the sensor assembly by providing an alarm signal. In this regard, the sensor assembly can be a fully analog system or a digital system.

[0160] Furthermore, according to some exemplary embodiments, the flue is sized so that the mean free path of the gas being sensed is not obstructed. In this regard, the flue diameter is approximately 100 times the mean free path of one of the gas being measured and the ambient air. Furthermore, the sensing response time is adapted to remain within acceptable limits based on the length of the flue, which is approximately 0.1 to 3 meters. In some embodiments, the flue diameter is greater than 10 mm.

[0161] Furthermore, according to some exemplary embodiments, a method for determining a gas leak using a sensor assembly including a primary sensing device and a reference sensing device includes determining a first oxygen concentration level for a given area via a flue extension coupled to the reference sensing device and determining a second oxygen concentration level for the given area via the primary sensing device. A control circuit is configured to compare the determined first and second oxygen concentration levels and, based on the comparison, trigger an alarm or notification if a difference between the first and second oxygen concentration level readings is greater than a threshold difference.

[0162] Furthermore, according to some exemplary embodiments, each of the primary sensing device and the reference sensing device is exposed to the same environmental variable, wherein the primary environmental variable includes at least one of temperature, pressure, and humidity.

[0163] Furthermore, according to some exemplary embodiments, the flue extension is configured to screen out one or more target gases from reaching the reference sensing device.

[0164] Furthermore, according to some exemplary embodiments, the primary sensing device is adapted to be exposed to a potential leak source, and the reference sensing device is adapted to be exposed to an environment other than the potential leak source under the same environmental variables.The diameter of the flue is about 100 times the mean free path of the one or more target gases.

[0165] Furthermore, according to some exemplary embodiments, one or more environmental variables are received and the first oxygen concentration level reading and the second oxygen concentration level reading are corrected based on the environmental variables. The method is executed via at least one processor.

[0166] One advantage of using a flue on the sensing sensor and / or reference sensor is that it allows the sensor to passively access gases from different parts of the HVAC system. This also means that the sensors can be located in less challenging environmental conditions. For example, areas where gas leaks may accumulate may be subject to harsh environments (such as large temperature and / or RH fluctuations), and the sensors can be connected to these areas via the flue. Using the described flue allows the sensors to be installed in milder areas with consistent temperatures. The sensors can also be isolated from areas where gas leaks may accumulate to provide an environment with a lower operating temperature. Isolating the sensor from the harsh environment allows the sensor to provide more accurate performance, minimizes compensation and referencing difficulties, thereby reducing false alarms and extending sensor life.

[0167] The various embodiments discussed herein allow for monitoring and detecting gas leaks during operation, such as in refrigeration units. While the various embodiments discuss refrigeration units, the various embodiments discussed herein can also be used for other types of gas leaks using closed-loop cycles, such as in HVAC applications, etc. Refrigeration units include closed-loop cooling / refrigerant coils that contain flammable refrigerants. A2L refrigerants are more commonly used in such refrigeration units due to their lower global warming potential (GWP), and therefore regulations have been enacted in many countries to monitor for leaks to avoid hazardous conditions during use. Although A2L refrigerants generally have low toxicity and are only mildly flammable, large leaks can still create hazardous conditions. Therefore, monitoring and detection of such leaks are necessary for refrigerant units. The various embodiments disclosed herein allow for simple and effective leak monitoring systems.

[0168] In some embodiments, some of the operations described above may be modified or further amplified. In addition, in some embodiments, additional optional operations may also be included. The modification, addition, or amplification of the operations described above may be performed in any order and in any combination.

[0169] Those skilled in the art to which the present invention belongs will think of many modifications and other embodiments set forth herein after having benefited from the teachings presented in the foregoing description and the associated drawings. Therefore, it should be understood that the present disclosure is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, it is also conceivable to combine elements and / or functions that are different from those explicitly described above, as may be shown in some of the appended claims. Although specific terms are employed herein, they are used only in a general and descriptive sense, and not for the purpose of limitation.

Claims

1. A heating, ventilation and air conditioning (HVAC) system, comprising: catheter unit; a sampling tube fluidly coupled to an opening defined in the conduit, wherein the sampling tube is positioned outside the conduit and extends in the direction of gravity; a sensor assembly fluidly coupled to the sampling tube, the sensor assembly configured to receive one or more gases having a greater density than ambient air, wherein the sensor assembly is configured to sense the one or more gases to generate a signal; as well as A flush tube having a first end and a second end, wherein the flush tube is fluidly coupled to the catheter unit at the first end of the flush tube and is fluidly coupled to the sensor assembly at the second end of the flush tube, and wherein the flush tube is configured to receive one or more gases including ambient air from the catheter unit. 2 . The HVAC system of claim 1 , wherein the sensor assembly includes a first opening configured to allow one or more gases to diffuse through the first opening.

3. The HVAC of claim 2, wherein the first opening includes a filter configured to screen dust and moisture from the one or more gases reaching the sensor assembly.

4. The HVAC system of claim 1, wherein the second end is positioned downstream of an opening one of the duct. 5 . The HVAC of claim 1 , further comprising a drain tube fluidly coupled to the sensor assembly, the drain tube configured to allow one or more gases to flow from the sensor assembly. 6 . The HVAC system of claim 1 , further comprising a blower disposed inside the duct unit, the blower being configured to be periodically activated to blow the ambient air into the flushing duct.

7. The HVAC system of claim 1, wherein: The catheter unit comprises: catheter: the sensor assembly; the opening one, along the direction of gravity, the opening one being fluidly coupled to a sampling tube positioned outside the conduit; and The second opening is complementary to the first opening and is along the fluid flow direction, and the second opening is fluidically connected to an irrigation tube positioned outside the catheter.

8. The HVAC system of claim 7, wherein the sensor assembly includes a first opening, the first opening including a filter configured to screen dust and moisture from one or more gases passing therethrough.

9. The HVAC system of claim 8, wherein the one or more gases include a refrigerant.

10. The HVAC of claim 7, wherein the sensor assembly includes a second opening fluidly coupled to a flush tube, wherein the flush tube includes a bend and is oriented toward the blower to facilitate flow of one or more gases including ambient air.

11. The HVAC system of claim 7, wherein: The catheter unit further includes a blower configured to facilitate the flow of one or more gases to the irrigation tube, wherein the blower is configured to be activated at periodic time intervals.

12. A sensor assembly, comprising: a chamber fluidly coupled to the sampling tube, the chamber configured to receive one or more gases from the sampling tube, wherein the chamber comprises: a second opening configured to allow the received one or more gases to flow therethrough; and a gas sensor disposed within the chamber, the gas sensor configured to sense the one or more gases to generate a signal; A flush tube having a first end and a second end, wherein the flush tube is fluidly coupled to the catheter unit at the first end of the flush tube and is fluidly coupled to the sensor assembly at the second end of the flush tube, and wherein the flush tube is configured to receive one or more gases including ambient air from the catheter unit.

13. The sensor assembly according to claim 12, wherein: The flush tube is configured to facilitate a flow of the ambient air toward the chamber to evacuate the one or more gases from the chamber, wherein when the flush tube is configured to receive the one or more gases comprising ambient air from a conduit, the flush tube evacuates the one or more gases from the chamber and the gas sensor.

14. The sensor assembly of claim 13, further comprising a drain fluidly coupled to the chamber, the drain configured to allow the one or more gases to escape therefrom upon receiving ambient air from the flush tube.

15. The sensor assembly of claim 12, comprising a first opening, wherein the first opening comprises a filter configured to screen dust and moisture from one or more gases reaching the chamber.

16. The sensor assembly of claim 13, wherein the flush tube includes a plurality of heat exchange fins to reduce the temperature of one or more gases reaching the chamber.

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