Gas detector with heat dissipation

Abstract

The present disclosure provides a gas detector. The gas detector has a housing defining a cavity, and a display module is disposed within the cavity. The display module has a first PCB, a backplane, a metal housing, and a thermal gap pad. The metal housing is positioned on top of the base plate, and the thermal gap pad is disposed between the metal housing and the second PCB. The second PCB is disposed on top of the thermal gap pad.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate generally to explosion proof gas detectors, and more particularly to gas detectors with heat dissipation during operation. Background Art

[0002] In order to prevent the explosion of combustible gas after reaching a certain concentration and ensure the safety of production, combustible gas detection and alarm devices are usually installed in factories or facilities that produce and use combustible gas. The main component of such combustible gas detection and alarm devices is the combustible gas detector. The current combustible gas detector is mainly composed of a gas sensor, a gas sensor fixing sleeve, a rain cover and a cable entry device.

[0003] At present, combustible gas detectors of this type of structure are essentially unsafe, so when applied in a combustible gas environment, there is a risk of detonating the surrounding environment, and it is generally impossible to meet more stringent explosion-proof requirements. Therefore, explosion-proof packaging is required. The traditional explosion-proof packaging method of combustible gas detectors is to encapsulate the catalytic beads in a stainless steel shell, which has a sintered sheet for flame capture and extinguishing, and the end of the shell is cast with epoxy resin to prevent leakage. According to the explosion-proof certification standards in Europe and North America, it is required that for any explosion-proof shell, if a sealant is used for sealing, the bonding length between the sealant and the shell in the sealing direction should not be less than 3mm. In addition, the design sealed with a sealant requires sufficient size so that the explosion-proof effect can be ensured. Therefore, the size of the traditional design is usually large, and a compact and portable combustible gas detector cannot be achieved.

[0004] Generally, the measuring devices of combustible gas detectors include: thermal conductivity detectors, infrared detectors and catalytic combustion detectors, etc. Most of these detection devices adopt the method of heat measurement, that is, the combustible gas is detected by the influence of the temperature or heat of the sensitive element caused by the flow, infrared absorption or combustion of the combustible gas. However, according to common sense, any detection involving heat measurement will inevitably be affected by the temperature change of the surrounding environment. Therefore, thermal measurement sensors usually require reference detectors or reference elements to eliminate the influence of environmental factors such as temperature, humidity, pressure and airflow on the measurement of the detection element. The reference element needs to be infinitely consistent with the detection element in several factors such as temperature, humidity, pressure and airflow so that the maximum compensation effect can be achieved. Unfortunately, due to product design and less advanced production technology, the compensation effect of the reference element in current combustible gas detectors (especially catalytic combustion or thermal conductivity sensors) is not ideal. That is to say, at present, although the combustible gas detectors manufactured by most manufacturers are compensated by reference elements, they are still significantly affected by temperature, humidity, pressure and airflow.

[0005] Existing explosion-proof gas detectors have a metal housing and a display module that allows the operator to configure the gas detector by displaying the device status. The display module has an LCD display, a PCB, and electronic components enclosed by a plastic cover. During operation of the gas detector, the electronic components of the gas detector generate heat, and the metal housing helps maintain the internal temperature of the gas detector to ensure device performance. With this metal housing, the heat is retained inside the device and is not dissipated to the outside. Summary of the invention

[0006] Exemplary embodiments of the present disclosure relate to a gas detector configured to dissipate heat. The gas detector has: a housing defining a cavity, the housing including a top component and a bottom component, the top component being coupled to the bottom component; and a display module. The display module is positioned within the cavity of the housing, and the display module has a first PCB, a second PCB, a bottom plate, a metal housing, and a thermal gap pad. The metal housing is positioned on top of the bottom plate, and the thermal gap pad is disposed between the metal housing and the second PCB, wherein the second PCB is positioned between the first PCB and the thermal gap pad.

[0007] In an example embodiment, the display module has an LCD display, and the LCD display is positioned on top of the first PCB.

[0008] In an example embodiment, an outer surface of the top component has a threaded portion and an inner portion of the bottom component has a threaded surface.

[0009] In an example embodiment, the bottom member has a display module support for receiving the display module, wherein the display module support is in contact with the bottom plate of the display module.

[0010] In an example embodiment, the display module support has a contact metal plate in contact with the base plate of the display module.

[0011] In an exemplary embodiment, the diameter of the metal housing is in the range of 103 mm to 108 mm.

[0012] In an exemplary embodiment, a display module includes a first PCB, a second PCB, a base plate, a metal housing, and a thermal gap pad, wherein the metal housing is positioned on top of the base plate, and the thermal gap pad is disposed between the metal housing and the second PCB, wherein the second PCB is positioned between the first PCB and the thermal gap pad.

[0013] In an example embodiment, the display module further includes an LCD display, wherein the LCD display is positioned on top of the first PCB.

[0014] In some embodiments, the diameter of the metal housing is in the range of 103 millimeters (mm) to 108 mm.

[0015] In an exemplary embodiment, the thermal gap pad has a length in the range of 60 millimeters (mm) to 80 mm.

[0016] In some embodiments, a gas detector includes a housing defining a cavity, a display module positioned within the cavity of the housing, the display module having a first PCB and a second PCB, a base plate, a metal housing, and a thermal gap pad. The metal housing is positioned on top of the base plate, and the thermal gap pad is disposed between the metal housing and the second PCB. The second PCB is disposed on top of the thermal gap pad.

[0017] In an example embodiment, the first PCB is disposed on top of the second PCB, and a bottom surface of the first PCB abuts a top surface of the second PCB.

[0018] In an example embodiment, the display module has an LCD display, and the LCD display is positioned on top of the first PCB.

[0019] In an example embodiment, an outer surface of the top component has a threaded portion and an inner portion of the bottom component has a threaded surface.

[0020] In some embodiments, the bottom member has a display module support for receiving the display module, and the display module support contacts the bottom plate of the display module.

[0021] In an example embodiment, the display module support has a contact metal plate in contact with the bottom plate of the display module.

[0022] In some embodiments, the diameter of the metal housing is in the range of 103 mm to 108 mm.

[0023] In one embodiment, the gas detector has a third PCB disposed adjacent to the bottom surface of the first LCD.

[0024] The above-mentioned summary of the invention is provided only for the purpose of summarizing some exemplary embodiments, so as to provide a basic understanding of some aspects of the present disclosure. Therefore, it should be understood that the above-mentioned embodiments are only examples and should not be construed as narrowing the scope or essence of the present disclosure in any way. It should be understood that in addition to those summarized here, the scope of the present disclosure also covers many possible embodiments, some of which will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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 figures are not necessarily drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating the teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:

[0026] Figure 1 shows an exploded view of a gas detector according to an example embodiment of the present disclosure;

[0027] FIG. 2( a ) is an exploded view of a display module according to an example embodiment of the present disclosure;

[0028] FIG2( b ) shows a cross-sectional view of a display module according to an example embodiment of the present disclosure;

[0029] Figure 3 shows a metal housing of a display module of a gas detector according to an example embodiment of the present disclosure;

[0030] Figure 4 A thermal gap pad of a display module of a gas detector according to an example embodiment of the present disclosure is shown;

[0031] 5( a ) and 5( b ) show various views of a contact metal plate of a gas detector according to an example embodiment of the present disclosure; and

[0032] Figure 6 The flow of heat in a gas detector during operation of the gas detector according to an example embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0033] Some embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. In fact, the present disclosure 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 satisfies applicable legal requirements. Unless otherwise indicated, the terms "or" and "optionally" are used herein both in the sense of selection and in the sense of conjunction. The terms "exemplary" and "exemplary" are used for examples without indication of a quality level. The same mark always refers to the same element.

[0034] In many working environments, explosion-proof gas detectors are used to monitor the gas level in the environment and warn the user when the monitored gas level increases to exceed a predetermined threshold. The gas detector has a display module for displaying the operating status of the gas detector and other information about the gas detector. The explosion-proof gas detector has an explosion-proof container, and the electrical equipment of the gas detector is placed in the explosion-proof container. The explosion-proof container is usually made of metal and has a completely closed structure. The explosion-proof container can withstand high pressure and high temperature when a gas or steam explosion occurs.

[0035] During the operation of the gas detector, electrical components such as circuit boards and wiring continuously generate heat within the gas detector. The heat so generated is retained within the explosion-proof container and cannot be dissipated to the external environment. The components of the circuit board are difficult to operate when the ambient temperature is high. When the heat exceeds a predetermined level, the operation of the components of the circuit board is affected. For this reason, some existing gas detectors with explosion-proof housings cannot effectively dissipate the heat generated inside the gas detector, thereby affecting the operation of the electrical components of the gas detector.

[0036] Various example embodiments described in the present disclosure relate to an explosion-proof gas detector having a heat dissipation for dissipating the generated heat from the housing of the gas detector. The gas detector has a housing defining a cavity, and a display module is placed in the cavity. The display module has an LCD display, a first PCB, a second PCB, a bottom plate, a metal housing, and a thermal gap pad. The metal housing is explosion-proof and positioned above the bottom plate, and the thermal gap pad is positioned above the metal housing so that the bottom surface of the thermal gap pad abuts the top surface of the metal housing. The second PCB is disposed between the thermal gap pad and the first PCB. The first PCB is positioned close to the LCD display of the display module.

[0037] Details regarding the components of the position sensor and how it works are described in detail with reference to the subsequent figures and detailed description.

[0038] The components shown in the figures represent components that may or may not be present in the various example embodiments of the disclosure described herein, such that an embodiment may include fewer or more components than shown in the figures without departing from the scope of the disclosure.

[0039] Turning now to the drawings, the detailed description shown below in conjunction with the drawings is intended to describe various example configurations and is not intended to represent the only configuration in which the concepts described herein may be practiced. The detailed description includes specific details in order to provide a thorough understanding of the various concepts, and the same numbers represent the same components in several views. However, it is apparent to those skilled in the art that these concepts may be practiced without these specific details.

[0040] Figure 1 1 is an exploded view of a gas detector 100 according to an example embodiment of the present disclosure. The gas detector 100 is explosion-proof and has a housing having a bottom component 102, a display module 104, and a top component 106. The gas detector 100 has a display module support assembly 108 disposed on an inner wall within a cavity of the bottom component 102. In an assembled state, the display module 104 is positioned above the display module support assembly 108 within the bottom component 102, and the top component 106 completely encloses the display module 104. The top component 106 has a circular window 110 through which a user can observe the display module 104 and read information displayed on the display module 104. In one example, the inner wall of the housing 103 has a threaded surface, and the outer wall of the top component 106 has a threaded surface for coupling. In one example, the bottom component 102 and the top component 106 are coupled so that a user can disassemble and separate the top component 106 from the bottom component 102.

[0041] FIG. 2( a) and FIG. 2( b) illustrate components of a display module 104 according to an embodiment of the present disclosure. The display module 104 includes a liquid crystal display (LCD) 200, a first PCB 202 (also referred to as a processor PCB), a second PCB 204 (also referred to as a terminal PCB), a base plate 206, a metal housing 208, and a thermal gap pad 210. The display module 104 also has a third PCB 212 (referred to as a heater PCB), which is positioned close to the bottom surface of the LCD 200. The operating temperature of the gas detector 100 is typically between -55°C and 75°C. In one example, when operating at low temperatures, the heater PCB 212 is used to generate heat inside the display module 104 to protect components from the low temperature that affects the performance of the components of the display module 104. In an operating environment with moderate to high temperatures, the PCBs 202, 204, and the heater PCB 212 generate heat inside the display module 104 during operation, thereby raising the temperature to above 75°C. Such high temperature may affect the performance of electrical components or damage the display module 104 and components of the gas detector 100. Since the PCB, other components of the gas detector 100, and the display module 104 are packaged by the metal housing 208, the heat is not completely dissipated to the outside. In addition, the bottom component 102 and the top component 106 are connected to each other by a threaded surface, thereby not providing any gap therebetween and preventing heat dissipation.

[0042] In addition, most of the heat generating components such as isolators, transistors, relays, diodes, LDOs, etc. are arranged close to the bottom surface of the second PCB 204 (or the terminal PCB). In one example, the heat generating components are connected to a thermal gap pad 210 between the heating PCB 212 and the bottom shell arranged at the bottom surface of the display module 104 for heat dissipation. The thermal gap pad 210 is placed between the second PCB 204 and the bottom shell of the display module 104. In addition, the bottom shell, which is usually made of plastic material, is replaced with a metal shell for improved heat dissipation.

[0043] According to an embodiment of the present disclosure, the metal housing 208 is Figure 3 204. The metal housing 208 is shown in FIG. The metal housing 208 has a main body 300, which is circular in shape and is positioned close to the bottom surface of the second PCB 204. As shown, the main body 300 has a small amount of gaps, such as 302 and 304. Gaps 302 and 304 are used to accommodate electrical components of different heights on the second PCB 204. The main body 300 has a molding area 306 and a small amount of through holes 308 and 310 for connecting the metal housing 208 with the bottom surface of the display module 104. The molding area 306 reduces the gap with the PCB component so that the 1.St gap pad can be placed therebetween to contact the metal housing and the PCB component. In one example, the diameter of the main body 300 is 105.00 millimeters (mm) (approximately). The width of the molding area 306 is about 22mm (approximately), the length is 54mm (approximately), and the gap between the two through holes is about 64mm (approximately).

[0044] In one example, the electrical components have different structures and heights, and there may be different gaps between the metal housing 208 and these components. In order to make the components contact the metal housing uniformly, a soft material with high thermal conductivity (referred to as a thermal gap pad 210) is placed between the electrical components and the metal housing 208 for effective heat dissipation.

[0045] Figure 4A thermal gap pad 210 according to an embodiment of the present disclosure is shown. The thermal gap pad 210 is disposed between the second PCB 204 and the bottom case. In one example, the thermal gap pad 210 is a soft and compliant gap filling material with a thermal conductivity of 3.0 W / mK. Due to the unique 3.0 W / mK filler encapsulation and low modulus resin formulation, the material provides thermal performance at low pressure. This material is ideal for applications that require lower stress on components and circuit boards during assembly. The thermal gap pad 210 maintains conformable properties, allowing fast recovery and excellent wetting characteristics, even for surfaces with high roughness and topography. The thermal gap pad 210 has a body 400 and a small number of recessed portions 402 and 404 to align with a metal housing 208 disposed below the thermal gap pad 210. In one example, the length of the thermal gap pad 210 is in the range of about 60 mm to 80 mm, the width is about 50 mm, and the thickness is about 0.508 mm to 3.175 mm. The operating temperature range of the thermal gap pad 210 is from -60°C to 200°C. Each recess 402 is about 5 mm in length, 10 mm in width, and the length of the recess 404 is about 10 mm. In one example, the thermal gap pad 210 is made of a silicone polymer mixed with a thermal medium (usually ceramic). During the manufacture of the thermal gap pad 210, silicone and ceramic powders are mixed, cast, and cured into a soft conformal thermal pad material in sheet form. In one example, the thermal gap pad 210 has glass fiber as a reinforcement carrier.

[0046] Referring to Figures 5(a) and 5(b), various views of the display module support assembly 108 according to an embodiment of the present disclosure are shown. The display module support assembly 108 has a contact metal plate 502, a support portion 504, and a spring sheet 506 as sub-components. In one example, the support portion 504 is made of metal. When the display module 104 is set on the inner wall of the bottom component 102, the contact metal plate 502 and the support portion 504 provide support for the display module 104. The support portion 504 and the spring sheet 506 push the display module 104 to contact the glass of the top 106 of the transmitter housing. This allows the position of the display module 104 to be fixed to prevent movement or vibration. In addition, the support portion 504 simultaneously puts the display module 104 in a floating state. The contact metal plate 502 contacts the metal housing of the display module 104. In one example, the bottom surfaces of the display module support assembly 108 and the display module 104 are aligned so that the metal housing 208 and the support portion 504 are in direct contact with each other. The contact of the metal housing 208 and the support portion 504 allows heat to be directly transferred from the metal housing 208 to the support portion 504. The spring 506 provides optimal support for the display module 104 to withstand vibration. In addition, the contact metal plate 502 is made of phosphor bronze C521 OH. The contact metal plate 502 is a folded metal sheet that acts as a spring and remains connected to the display module 104 based on the tension generated by the spring. The flank shape of the contact metal plate 502 contacts the inner side wall of the transmitter housing bottom part 102 for heat dissipation by conduction.

[0047] Figure 6 The flow of heat within the gas detector 100 from the first PCB 202 to the bottom member 102 of the gas detector 100 according to an embodiment of the present disclosure is shown. The overall goal is to direct the heat generated inside the PCB (such as PCB 202) to the bottom member 102 and then dissipate the heat from the bottom member 102 to the external environment. In one example, a fan (not shown in the figure) is attached to the bottom case to extract the heat generated in the PCB and draw the heat to the bottom member 102 of the display module 104. Figure 6 The arrows in the diagram indicate the direction of heat flow.

[0048] As shown, heat is generated by electrical components (such as PCB 202, PCB 204, and heater PCB 212) within the display module 104, and the heat generated by the electrical components is absorbed by the thermal gap pad 210, and then the heat is transferred from the thermal gap pad 210 to the metal housing 208. The metal housing 208 is in contact with the support portion 504 of the display module support assembly 108. The heat is then transferred to the display module support assembly 108. The display module support assembly 108 is in contact with the metal surface of the bottom member 102. The heat is then transferred to the metal body of the bottom member 102, and then transferred to the external environment through the metal body of the bottom member 102.

[0049] In another example, the display module support assembly 08 is disposed on the inner wall of the bottom member 102, and the bottom surface of the display module 104 contacts the display module support assembly 108, so that the heat generated inside the display module 104 is transferred from the bottom surface of the display module 104 to the display module support assembly 108, and then dissipated to the external environment through the bottom member 102. In one example, the components for heat dissipation are accommodated in the housing without occupying any additional space or increasing the size of the gas detector 100. The present invention provides the advantage of improved heat dissipation without increasing the footprint or size of the gas detector 100 or the display module 104.

[0050] References in this specification to "one embodiment," "embodiment," "multiple embodiments," or "one or more embodiments" are intended to indicate that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. In addition, various features are described that may be present in some embodiments but not in other embodiments. Similarly, various requirements are described that may be requirements of some embodiments but not in other embodiments.

[0051] It should be noted that when used in this disclosure, the terms "comprises," "includes," and other derivatives from the root term "comprising" are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to exclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.

[0052] As required, detailed embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary and can be embodied in various forms. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but only as the basis for the claims, and are representative bases for teaching those skilled in the art to adopt the present disclosure differently with substantially any appropriate detailed structure.

[0053] Although it is obvious that the exemplary embodiments disclosed herein achieve the above-mentioned objects, it should be understood that many modifications and other embodiments can be designed by those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and embodiments that fall within the spirit and scope of the present disclosure.

Claims

1. A gas detector, comprising: a housing defining a cavity, the housing including a top member and a bottom member, the top member coupled to the bottom member; A display module, the display module is positioned in the cavity of the housing, and the display module comprises: First PCB; Second PCB; Base plate; Metal casing; and thermal gap pads where the metal housing is positioned on top of the base plate, and the thermal gap pad is disposed between the metal housing and the second PCB, Wherein the second PCB is positioned between the first PCB and the thermal gap pad. 2 . The gas detector of claim 1 , wherein the display module further comprises an LCD display, and the LCD display is positioned on top of the first PCB. 3 . The gas detector according to claim 1 , wherein an outer surface of the top member has a threaded portion, and an inner portion of the bottom member has a threaded surface. 4 . The gas detector according to claim 1 , wherein the base member has a display module support for receiving the display module, wherein the display module support is in contact with the bottom plate of the display module. 5 . The gas detector according to claim 3 , wherein the display module support has a contact metal plate in contact with the bottom plate of the display module.

6. The gas detector according to claim 1, wherein a diameter of the metal housing is in a range of 103 mm to 108 mm.

7. A display module, comprising: First PCB; Second PCB; Base plate; Metal housing; and A thermal gap pad is provided, wherein the metal housing is positioned on top of the base plate and the thermal gap pad is disposed between the metal housing and the second PCB, wherein the second PCB is positioned between the first PCB and the thermal gap pad.

8. The display module of claim 7, wherein the display module further comprises an LCD display, wherein the LCD display is positioned on top of the first PCB. 9 . The display module of claim 7 , wherein a length of the thermal gap pad is in a range of 60 millimeters (mm) to 80 mm.

10. The display module of claim 7, further comprising a third PCB disposed adjacent to a bottom surface of the LCD.

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