Enclosure for a refrigerant gas leak detection sensor and refrigerant gas leak detection sensor with an enclosure

Abstract

The present invention pertains to an enclosure for a refrigerant gas leak detection sensor, comprising a top part, a bottom part and a PCBA with a sensing element. Preferably, the enclosure is made of plastic. A gasket is provided between the sensing element and the bottom part. The invention also pertains to a refrigerant gas leak detection sensor with an enclosure.

Description

[0001] Enclosure for a refrigerant gas leak detection sensor and refrigerant gas leak detection sensor with an enclosure

[0002] Description

[0003] The present invention pertains to an enclosure for a refrigerant gas leak detection sensor, comprising a top part, a bottom part and a PCBA with a sensing element. Preferably, the enclosure is made of plastic. A gasket is provided between the sensing element and the bottom part. The invention also pertains to a refrigerant gas leak detection sensor with an enclosure.

[0004] Known refrigerant gas leak detection sensors and their enclosures are used in HVAC applications, where they may have to endure difficult operating conditions.

[0005] The enclosures are typically used to protect the refrigerant gas leak detection sensor from high temperature, humidity, water spray, refrigerant oil spray, dust, vibrations and other environmental factors fulfilling I P (ingress protection) code e.g. I EC 60529. The enclosure of the refrigerant gas leak detection sensor must be designed in such a way that it protects the sensing element from all of the above environmental factors. However, the enclosure still needs to provide a passage for refrigerant gas to come into contact with the sensing element inside the enclosure.

[0006] Known sensors and their enclosures must overcome the problem of protecting the inside of the sensor while at the same time minimizing the mechanical strain on the sensor components. For example, in order to prevent dust and water ingress into the enclosure, O -rings have to be manually added for sealing screw connections, thereby complicating the manufacture of the device.

[0007] The aim of the present invention is to provide an improved enclosure for a refrigerant gas leak detection sensor and a corresponding refrigerant gas leak detection sensor, which overcome the above outlined problems.

[0008] This aim is achieved by an enclosure for a refrigerant gas leak detection sensor according to claim 1 and a refrigerant gas leak detection sensor according to claim 9. Preferable embodiments of the invention are subject to the dependent claims.

[0009] According to claim 1 , an enclosure for a refrigerant gas leak detection sensor is provided. The enclosure comprises a top part and a bottom part. Both parts may comprise circular outer perimeter portions. The top part may be at least partially concave to accommodate sensor components. The bottom part may be substantially flat and / or sensor components may be attached to it. A PCBA with a sensing element is provided between the top part and the bottom part. A gasket is provided between the PCBA and the bottom part. The gasket may be in direct contact with the PCBA and / or the sensing element. The top part and the bottom part may sandwich the PCBA, preferably at screw towers of the top part. Accordingly, there may be no direct physical contact between the top part and the bottom part.

[0010] The gasket may be provided at, within or formed integrally with the bottom part. The gasket may be in direct contact with the bottom part on one side and with the sensing element on its other side. The gasket reduces mechanical strain on the gas sensing element and prevents water and dust from entering into the enclosure. The gasket may also have additional features such as ribs for reducing the mechanical strain on the assembly. The gasket may comprise features acting as an O-ring in screw towers, thus reducing the mechanical strain on the PCB when the assembly is screwed together.

[0011] The top part and bottom part define an enclosure, which is designed such that the sensing element is facing an external mounting surface. The mounting surface may be an external surface of an apparatus with a working fluid, the properties of which are to be measured by the presently described device. The sensing element is protected against dust, oil , water, and other environmental factors. The enclosure may comprise features which increase its structural strength, thereby reducing the mechanical strain on the PCB.

[0012] The present invention makes it possible to qualify the gas sensor for an I P 54 grade I EC 60529. The gasket around the sensing element enables this increase in I P rating. The gasket may also act as an O-ring at the screw towers preventing the need for an additional component in the assembly, thus reducing the complexity. The gasket may be over-molded during the injection molding process, thereby reducing the risk associated with the handling of the gasket during assembly and preventing any damage to the soft gasket material.

[0013] I n a preferred embodiment of the invention, the gasket is over-molded on the bottom part. The over-molding of the gasket simplifies its manufacture and facilitates the provision of intricate gasket geometries with a multitude of functionalities.

[0014] I n another preferred embodiment of the invention, the top part and the bottom part are connected to each other by means of fasteners. The fasteners may comprise screws, bolt, catch mechanism and / or other features. The fasteners may be formed integrally with either of the top part and the bottom part and / or they may comprise components which are distinct from the top part and the bottom part. Various types of fasteners may be used in a single device.

[0015] I n another preferred embodiment of the invention, the gasket comprises O-ring portions for accommodating the fasteners, wherein preferably the gasket comprises bridge portions for connecting the O-ring portions to the remainder of the gasket. The O-ring portions may be arranged around a central and preferably hollow portion of the gasket. I n another preferred embodiment of the invention, the bottom part comprises a reinforced rib structure. Ribs may be provided inside the top part and / or the bottom part for mechanical strength.

[0016] I n a particularly preferred embodiment of the invention, the reinforced rib structure provides a flow path for the gasket and / or comprises a boss for accommodating the fasteners. The ribs may act as flow paths for the gasket during the over-molding process of the gasket.

[0017] I n another preferred embodiment of the invention, the bottom part comprises a light guide for providing a light path out of the enclosure. The light path connects the outside of the enclosure to the electronic components on its inside, such that light signals can be received and / or emitted by the electronic components. The light from the light path may be reflected from the surface (e.g. wall) on which the refrigerant gas leak detection sensor is mounted to and be visible via e.g. vent holes.

[0018] I n another preferred embodiment of the invention, vent holes are provided in the top part for providing a fluid connection between the outside of the enclosure on the one side and the bottom side of the bottom part and / or the sensing element on the other side. The vent holes may fulfill two different tasks. The first tasks is providing a fluid path for the sensing element, such that gas leaks can be detected swiftly. The second task is providing a light passage from underneath the enclosure such that light emitted through the light guide may be visible from the outside of the enclosure.

[0019] The invention is also directed at a refrigerant gas leak detection sensor with an enclosure.

[0020] Further details and advantages are described with reference to the embodiments shown in the figures. The figures show:

[0021] Figure 1 : perspective view of the enclosure;

[0022] Figure 2: partially exploded view of the enclosure;

[0023] Figure 3: another partially exploded view of the enclosure;

[0024] Figure 4: pers pective view of the bottom part of the enclosure;

[0025] Figure 5: pers pective view of the contents of the enclosure;

[0026] Figure 6: pers pective view of the bottom part

[0027] Figure 7: another perspective view of the bottom part; Figure 8: another perspective view of the enclosure;

[0028] Figure 9: perspective view of the gasket; and Figure 10: perspective view of the light guide.

[0029] Figure 1 is a perspective view of the enclosure 10. The enclosure 10 is provided for a refrigerant gas leak detection sensor. The enclosure comprises a top part 14 and a bottom part 121. The bottom part 12 is visible only partially, as it is largely covered by and inserted into the top part 14. Both parts 12, 14 may comprise circular outer perimeter portions. The bottom part 12 may be arranged largely within the top part 14. The top part 14 may be at least partially concave to accommodate sensor components and / or portions of the bottom part 12.

[0030] The upper part 14 may comprise a number of vent holes 28, arranged close to its outer perimeter and / or injection molded together with the remainder of the upper part 14.

[0031] The bottom part 12 may comprise two or more mounting legs 34 with e.g. one mounting through hole 33 each, for mounting the enclosure 10 to a structure. The mounting legs 34 may protrude radially outward of the structure of the enclosure 10.

[0032] A connector 38 is provided for connecting the electronic components of the refrigerant gas leak detection sensor to other devices. The upper part 14 may comprise a recessed portion for accommodating the connector 38. The recessed portion may be formed integrally with the upper part 14 and during the molding of the upper part 14.

[0033] Figure 2 is a partially exploded view of the enclosure 10. The bottom part 12 may be substantially flat and / or sensor and / or other electronic components may be attached or attachable to the bottom part 12. A PCBA 42 is provided between the top part 14 and the bottom part 12. A connector 38 is provided at a connector flange 49. A first section 22 of the bottom part 12 may be shaped as a segment of a circle at its outer perimeter. The bottom part 12 may comprise three or four similar or identical circular outer perimeter sections of its first section 22. The first section 22 has a flat bottom part, which is raised with respect to mounting legs 34. This allows the light from the light path 52 shown in figure 3 to be reflected from a mounting wall, such that the reflected light can be transmitted from the wall through the vent holes 28 shown in figure 1. The light is thus visible through the vent holes 28 from the outside of the enclosure 10.

[0034] Figure 3 is a another partially exploded view of the enclosure 10. The external bottom side of the bottom part 12 is shown on the left and next to the internal bottom side of the upper part 14.

[0035] Fasteners 47, such as screws, are shown to penetrate the bottom part 12. The fasteners 47 are provided for connecting the bottom part 12 to the upper part 14. Three fasteners 47 are shown in the embodiment of figure 3, a greater or smaller number of fasteners 47 may be used. The screwheads of the fasteners 47 may press against the bottom side of the bottom part 12.

[0036] The fasteners 47 may comprise screws, bolts, catch mechanism and / or other features. The fasteners 47 may be formed integrally with either of the top part 14 and the bottom part 12 and / or they may comprise components which are distinct and separate from both, the top part 14 and the bottom part 12. I n the embodiment of figure 3, all fasteners 47 may be identical screws.

[0037] The bottom part 12 comprises a light guide 52 for providing a light path into the enclosure 10. The light path connects the outside of the enclosure 10 to the electronic components on its inside, such that light signals can be received and / or emitted by the electronic components. The light guide 52 may be provided on the same face of the bottom part 12 as the fasteners 47. The light guide 52 may comprise a transparent cover.

[0038] A channel 18 may be provided on the bottom side of the bottom part 12. The channel 18 may be at or close to the radially central portion of the bottom part 12. A sensing element 40, as shown later in figure 5, may be located inside the enclosure 10 and preferably concentrically to the channel 18. The channel 18 provides a communication path between the outside of the enclosure 10 and the sensing element 40.

[0039] A reinforced rib structure 50 may be provided at the bottom side of the bottom part 12. At least a part of the reinforced rib structure 50 may preferably be provided at the bottom side of the mounting leg 34. A reinforced rib structure 50 may also be provided on the inside of the upper part 14. The vent holes 28 are shown arranged along the circumference of the upper part 14. The vent holes 28 may be provided at a wall of the upper part 14, such as a preferably substantially vertical wall, extending between the substantially flat bottom part 12 and a horizontal portion of the upper part 14.

[0040] The vent holes 28 allow any gas from the surroundings to pass through enclosure 10 or rather through the upper part 14 of the enclosure. The gas is then lead into the channel 18 to be detected by the sensing element 40.

[0041] The upper part 14 may also comprise a reinforced rib structure 50, especially in the vicinity of bosses 51 for accommodating the fasteners 47. In the embodiment of figure 3, three bosses 51 are shown at the upper part 14.

[0042] The enclosure 10 may comprise further features, which increase its structural strength, thereby reducing the mechanical strain on its contents.

[0043] Figure 4 is a perspective view of the internal upper side of the bottom part 12 of the enclosure 10. The central main part of the bottom part 12 is mostly covered by the PCBA 42 and its components. The connector 38 is shown at a radially outer position of the PCBA 42 and close to an outer edge of the bottom part 12. Fasteners 47 are shown penetrating the PCBA 42. The fasteners 47 therefore not only connect the bottom part 12 to the upper part 14, but also fix the PCBA 42 in place.

[0044] Figure 5 is a perspective bottom view of the contents of the enclosure 10, namely of the PCBA 42. At the bottom of the PCBA 42, the sensing element 40 is provided in a central position. The sensing element 40 may be provided on a A2L PCB 46, itself provided on the PCBA 42. The connector 38 is provided on the PCBA 42 opposite the sensing element 42 and / or the A2L PCB 46.

[0045] I n the assembled state shown in e.g. figure 1 , the top part 14 and bottom part 12 define the enclosure 10, which is designed such that the sensing element 40 is facing a mounting surface at the outside of the enclosure 10. The sensing element 40 shown in figure 5 is thus protected against dust, oil, water, and other environmental factors.

[0046] Figure 6 is a perspective view of the bottom part 12. The PCBA 42 is not shown in this figure in order to provide more details on the gasket 45 and the bottom part 12. The gasket 45 may be provided along parts of the reinforced rib structure 50 and corresponding bosses 51 of the bottom part 12. The gasket 45 comprises a central opening around the channel 18. The reinforced rib structure 50 may comprise concentrically aligned, preferably circular rib portions and / or radially oriented, preferably longitudinal rib portions.

[0047] The gasket 45 may be formed within or formed integrally with the bottom part 12. The gasket 45 reduces mechanical strain on the gas sensing element 40 and prevents water and dust from ingress into the enclosure 10. The gasket 45 may also have additional features such as ribs for reducing the mechanical strain on the assembly.

[0048] The gasket 45 may be over-molded on the bottom part 12. The over-molding of the gasket 45 simplifies its manufacture and makes it possible to provide intricate gasket 45 geometries with a multitude of functionalities. The gasket 45 may be over-molded on circular and / or longitudinal rib portions of the bottom part 12. The gasket 45 may be over-molded on the radially innermost circular rib portion and two, three or more longitudinal rib portions.

[0049] The bottom part 12 may comprise a connector flange 49 for connecting the bottom part 12 to the connector 38 shown in e.g. figure 4. The two mounting legs 34 with their respective mounting through holes 33 are shown on opposite sides of the bottom part 12. Each of the mounting legs is oriented in a radial direction. The first section 22 is provided adjacent to the connector flange 49.

[0050] As seen in figures 6 and 3, ribs may be provided inside the top part 14 and / or the bottom part 12 for mechanical strength.

[0051] At least a part of the reinforced rib structure 50 may provide a flow path for the gasket 45 for facilitating the molding of the gasket 45.

[0052] Figure 7 is another perspective view of the bottom part 12. The two mounting legs 34 are shown with their respective mounting through holes 33. The mounting legs 34 comprise reinforced rib structures 50 and bosses 51 . The bottom side of the bottom part 12 comprises countersunk through holes 48 for accommodating the fasteners 47. The circular channel 18 may be surrounded by a chamfer 19. The first section 22 of the bottom part 12 is shown between the mounting leg 34 and the connector flange 49. Figure 8 is another perspective view of the enclosure 10 with its bottom part 12 and its upper part 14. The enclosure 10 is the exterior part of a refrigerant gas leak detection sensor. The sensor components are provided within the enclosure 10. Only the connector 38 is visible next to the connector flange 49, which holds the connector 38 in its place. The first section 22 is partially visible through the same opening as the connector 38.

[0053] Figure 9 is a perspective view of the gasket 45. The gasket 45 comprises a main central opening for sealing the sensing element 40 shown in figure 5. The main central opening is connected to three O-ring portions 53 via three bridge portions 54. The O-ring portions 53 are provided for accommodating the fasteners 47 shown in e.g. figure 4. The gasket 45 may thus be made to integrally comprise a number of different sealing portions, simplifying the manufacture of the gasket 45 considerably.

[0054] Figure 10 is a perspective view of the light guide 52. The light guide 52 may be a solid and transparent component, which is inserted into a hole in the bottom part 12 of the enclosure 10. The light guide 52 may comprise a long cuboid or cylindrical portion and a short cylindrical portion with curved shaped reflector output.

[0055] Reference numbers Enclosure Bottom part Top or upper part Channel Chamfer First section Vent hole Mounting through hole Mounting leg Connector Sensing element PCBA Gasket A2L PCB Fastener Countersunk through hole Connector flange Reinforced rib structure Boss Light guide O-ring portion Bridge portion

Claims

Claims1 . Enclosure (10) for a refrigerant gas leak detection sensor, comprising a top part (14), a bottom part (12) and a PCBA (42) with a sensing element (40) , characterized in that a gasket (45) is provided between the PCBA (42) and the bottom part (12).

2. Enclosure (10) according to claim 1 , characterized in that the gasket (45) is over-molded on the bottom part (12).

3. Enclosure (10) according to any of the previous claims, characterized in that the top part (14) and the bottom part (12) are connected to each other by means of fasteners (47).

4. Enclosure (10) according to the previous claim , characterized in that the gasket (45) comprises O-ring portions (53) for accommodating the fasteners (47) , wherein preferably the gasket (45) comprises bridge portions (54) for connecting the O-ring portions (53) to the remainder of the gasket (45).

5. Enclosure (10) according to any of the previous claims, characterized in that the bottom part (12) comprises a reinforced rib structure (50) .

6. Enclosure (10) according to at least claims 3 and 5, characterized in that the reinforced rib structure (50) provides a flow path for the gasket (45) and / or comprises a boss (51 ) for accommodating the fasteners (47).

7. Enclosure (10) according to any of the previous claims, characterized in that the bottom part (12) comprises a light guide (52) for providing a light path out of the enclosure (10).

8. Enclosure (10) according to any of the previous claims, characterized in that vent holes (28) are provided in the top part (14) for providing a fluid connection between the outside of the enclosure (10) on the one side and the bottom side of the bottom part (12) and / or the sensing element (40) on the other side.

9. Refrigerant gas leak detection sensor with an enclosure (10) according to any of the preceding claims.

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