Perceptron

Abstract

A sensor is provided with a first case, a second case, and a third case that are attached to a detection site. A plurality of ventilation windows extending in the axial direction are formed in the cylindrical portion of the second housing in the circumferential direction, one end side of each ventilation window in the axial direction corresponds to the position of the detection space, and the other end side of each ventilation window in the axial direction corresponds to the position of the first housing. The opening area of the ventilation window can be set to be sufficient relative to the area of the detection space. Moreover, air guide parts are arranged on the first shell, the second shell and the third shell, so that air on the upstream side of air flow can be guided to the detection space from the ventilation windows, and air from the detection space can be guided to the ventilation windows on the downstream side of the air flow. The air from the outside can smoothly flow into the detection space.

Description

Technical Field

[0001] This disclosure relates to a sensor. The sensor disclosed herein is useful, for example, as a smoke detector installed near electrical wiring or transformers in factories where there is a high risk of fire. Background Technology

[0002] Patent Document 1 discloses a smoke sensor that supports an insect-proof net via an air guide section. It should be noted that in Patent Document 1, the air guide section has a light-shielding function, forming a labyrinth wall.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-227446 Summary of the Invention

[0006] The smoke sensor shown in Patent Document 1 only has a ventilation window, an insect screen, and a maze wall around the outer perimeter of the detection space. The insect screen uses a fine mesh for its function. The maze also uses a maze structure for its function. Therefore, the insect screen and the maze may obstruct the flow of smoke, thus failing to efficiently guide the smoke into the detection space.

[0007] In view of the above, the present disclosure addresses the issue of preventing airflow from being obstructed by ventilation windows and air guides. In other words, it addresses the issue of allowing external air to flow smoothly into the testing space.

[0008] The sensor disclosed herein comprises: a first housing mounted on a detection unit; a second housing having an axially extending cylindrical portion, a bottom, and an opening, the bottom being formed at one axial end of the cylindrical portion and the opening at the other axial end of the cylindrical portion; and a third housing holding a detection element, a control unit, and a transmitting unit, the control unit controlling the detection element and the transmitting unit transmitting a signal detected by the detection element to the outside. Furthermore, the first housing is held inside the second housing at the opening side, and the third housing is held inside the second housing at one axial end side, with a detection space formed at one axial end side of the second housing for detection by the detection element.

[0009] In the sensor disclosed herein, multiple axially extending ventilation windows are formed in the circumferential direction in the cylindrical portion of the second housing. One axial end of the ventilation window corresponds to the position of the detection space, and the other axial end of the ventilation window corresponds to the position of the first housing. Furthermore, air guides are formed in the first housing, the second housing, and the third housing. These air guides direct air from the upstream side of the airflow through the ventilation windows to the detection space, and direct air from the detection space to the downstream side of the airflow through the ventilation windows.

[0010] In the sensor disclosed herein, a detection space, a third housing, and a first housing are arranged inside the second housing, starting from one axial end. That is, the detection space is formed in the second housing closer to one axial end than the locations of the first and third housings. In contrast, ventilation windows are formed in the cylindrical portion of the second housing extending from one axial end to the other. Furthermore, multiple ventilation windows are formed circumferentially. Therefore, the opening area of ​​the ventilation windows can be set to a size sufficient relative to the area of ​​the detection space.

[0011] In the sensor of this disclosure, a ventilation window extending axially is positioned opposite a detection space located at one end of the axial direction of the second housing, a third housing located at the middle of the axial direction, and a first housing located at the other end of the axial direction. Therefore, in the sensor of this disclosure, air guides are formed in the first housing, the second housing, and the third housing, connecting the ventilation window to the detection space. This directs air upstream of the airflow through the ventilation window to the detection space, and directs air from the detection space to the ventilation window downstream of the airflow. Attached Figure Description

[0012] Figure 1 This is a 3D view of the smoke sensor in this example.

[0013] Figure 2 This is a three-dimensional diagram showing the smoke sensor broken down.

[0014] Figure 3 This is a perspective view showing the first housing.

[0015] Figure 4 This is an axial sectional view of the first housing.

[0016] Figure 5 This is a perspective view showing the third housing.

[0017] Figure 6 It is along Figure 1 A cross-sectional view of the third housing along line VI-VI.

[0018] Figure 7 This is a perspective view showing the second housing.

[0019] Figure 8This is an axial sectional view of the second housing.

[0020] Figure 9 It is along Figure 1 A cross-sectional view of the second housing along line IX-IX.

[0021] Figure 10 It is along Figure 1 A cross-sectional view of the second housing along the XX line.

[0022] Figure 11 It is a cross-sectional view showing the configuration of the detector and the detection space.

[0023] Figure 12 This is a cross-sectional view showing the configuration of the notification light and the insect screen.

[0024] Figure 13 This is a 3D view showing the configuration of the smoke sensor.

[0025] Figure 14 This is a diagram illustrating the airflow into and out of the smoke sensor. Detailed Implementation

[0026] exist Figure 1 The diagram illustrates an example of using the sensor disclosed herein as a smoke detector 100. The smoke detector 100 is installed, for example, near electrical wiring or transformers in a factory where there is a high risk of fire. Therefore, the smoke detector 100 is installed in locations requiring electromagnetic interference resistance. The smoke detector 100 is sized for easy one-handed handling by a worker. The smoke detector 100 is cylindrical in shape, approximately 50 mm in diameter and 45 mm in height. Its total weight is approximately 50 grams.

[0027] exist Figure 2 The components of the smoke sensor 100 are shown in detail below. Figure 2 In this configuration, one end of the axial direction is positioned downwards, and the other end of the axial direction is positioned upwards. From the other end (above) of the axial direction, the first housing 120 and the third housing 150 are sequentially arranged. Furthermore, the second housing 130 is arranged to cover the first housing 120 and the third housing 150. Therefore, the first housing 120 and the third housing 150 are contained within the second housing 130.

[0028] The first housing 120 has an opening at one end along its axial direction, and the base 110 is disposed at this opening. Therefore, the base 110 is a component forming part of the first housing 120. The base 110 is made of a non-conductive resin material, such as ABS resin (acrylonitrile butadiene styrene resin). The base 110 is formed into a disc shape by injection molding of ABS resin. As mentioned above, its diameter is approximately 50 mm. The base 110 is fixed to the area being inspected using screws or double-sided tape. In most cases, the area being inspected is usually the ceiling of a building. However, in factory buildings, ventilation vents are often installed in the ceiling, supplying air downwards. Therefore, in the event of a fire, smoke is unlikely to reach the ceiling, and if the area around the ceiling is filled with smoke, the fire may have already progressed to a considerable extent.

[0029] In this example, the smoke detector 100 is not installed on the ceiling of the factory building, but rather on the production line. Specifically, as... Figure 13 As shown, the smoke detector 100 is disposed in a control box 200 where electrical wiring is concentrated, or in a transformer box housing a transformer. Alternatively, the smoke detector 100 may also be disposed in a safety enclosure housing cutting or welding machinery on a production line. These are enclosed spaces that will fill with smoke early in the event of a fire. Therefore, the base 110 is fixed to the top plate 201 of the space such as the control box 200. Thus, the detected location in this example is near the assumed smoke source. Since the top plate 201 needs to be machined with screws for fastening, the base 110 in this example is mainly fixed to the top plate 201 with double-sided tape.

[0030] It should be noted that, in Figure 13 In addition to the example fixed to the top plate 201, an example fixed to the side wall 202 is also shown. However, it is not common to configure two smoke detectors 100 in one control box 200. Figure 13 The example shown is for illustrative purposes, depicting a configuration fixed to sidewall 202. For instance... Figure 13 As shown, when the smoke detector 100 is fixed to the side wall 202, it is desirable to fix it in an upper position. In addition, a fan 203 for heat dissipation is usually arranged in the control box 200, so it is desirable to arrange the smoke detector 100 near the fan 203 and in a position affected by the airflow generated by the fan 203.

[0031] Typically, a production line is equipped with dozens to around 200 smoke detectors 100. Each smoke detector 100 has a transmitter 142, which will be described later. Signals from each smoke detector 100 are transmitted wirelessly to a receiver on the production line. Signals received by the receiver from each smoke detector 100 are then transmitted via communication lines such as the Internet and / or cloud systems on intranets to a management server located remotely from the production line. These communication lines include wired and / or wireless connections.

[0032] Similar to the base 110, the first housing 120 is also made of a non-conductive resin material. The first housing 120 is also formed by injection molding of ABS resin. The first housing 120 internally houses the battery 121. Specifically, battery retaining claws formed in the first housing 120 are elastically deformed, holding the battery 121 in place by their own elasticity. The battery 121 is electrically connected to a power connector 145 disposed on the substrate assembly 140, which will be described later. Through the power connector 145, the negative terminal is electrically connected to a grounding conductor film formed on the substrate assembly 140. Furthermore, the positive terminal is electrically connected to a power conductor film formed on the substrate assembly 140. In this example, a 3-volt battery 121 is used.

[0033] In the base 110, a latching claw is formed at a location corresponding to the recess 111. Furthermore, a connecting portion 122 is formed in the first housing 120 that engages with the latching claw of the base 110. By rotating the first housing 120 in conjunction with the base 110, the connecting portion 122 of the first housing 120 can engage with or disengage from the latching claw of the base 110.

[0034] The second housing 130 is also made of non-conductive resin material and is formed by injection molding of ABS resin. The second housing 130 is located at one axial end ( Figure 2 The lower end is closed, and the other end is axial ( Figure 2 The second housing 130 is a bottomed cylindrical shape with an opening at its upper end. The bottom 134, formed at one axial end, is hemispherical. The side of the second housing 130 is a cylindrical portion 135, on which a plurality of axially extending ventilation windows 131 are formed in the circumferential direction. In this example, 16 ventilation windows 131 are formed at equal intervals in the circumferential direction. A detection space 132 is formed at the center of the upper surface of the hemispherical bottom 134 of the second housing 130. In this example, the detection space 132 is a smoke detection space for detecting smoke.

[0035] One axial end of the ventilation window 131 corresponds to the position of the detection space 132, and the other axial end of the ventilation window 131 corresponds to the position of the first housing 120. That is, the ventilation window 131 is formed over approximately its entire axial length, from one axial end to the other axial end.

[0036] The other axial end of the second housing 130 is an opening 136, and a locking claw is formed on the inner circumference of the opening 136. The second housing 130 is fixedly connected to the first housing 120 by the locking claw. Therefore, the installation of the first housing 120 onto the base 110 involves all structural components of the smoke sensor 100, including the battery 121 held in the first housing 120 and the third housing 150 described later, being fixed to or removed from the base 110.

[0037] Inside the second housing 130, on one axial end side of the first housing 120, a third housing 150 is held. The third housing 150 has a container shape with the other axial end open, and a substrate assembly 140 is disposed at the opening of the third housing 150. The substrate assembly 140 is a member covering the opening of the third housing 150 and constitutes part of the third housing 150. The third housing 150 is made of a conductive resin material. The third housing 150 is, for example, injection molded from a resin material in which PA6 resin (6 nylon resin) is mixed with CF30 resin (carbon fiber reinforced resin). As described above, the third housing 150 has a container shape with one side (the other axial end side) open, and a light-emitting element 151 and a light-receiving element 152 are held inside the container shape. More specifically, the third housing 150 holds the light-emitting element 151 and the light-receiving element 152 at the position facing the smoke detection space 132. In the smoke detector 100 of this example, the light-emitting element 151 and the light-receiving element 152 function as the detection elements of the detector. It should be noted that the detection elements of the smoke detector 100 can also be provided by a chemical gas sensor that detects the gas composition.

[0038] On the radially inner side of the cylindrical portion 135 of the second housing 130, an insect screen 160 is provided to prevent foreign objects from entering the detection space 132 through the ventilation window 131. Since insects are a typical example of foreign objects, it is called an insect screen 160, but the insect screen 160 is not limited to preventing the intrusion of insects, but also prevents the intrusion of foreign objects such as dust.

[0039] The above is based on Figure 2The general structure of the smoke detector 100 has been described, followed by a detailed description of the first housing 120, the second housing 130, and the third housing 150. In particular, the structure of the air guide section that guides air (smoke) from the upstream side of the airflow through the ventilation window 131 to the detection space 132, while simultaneously guiding air from the detection space 132 to the downstream side of the airflow through the ventilation window 131, will be described.

[0040] Figure 3 and Figure 4 The first housing 120 is shown. These figures show the base 110 removed from the first housing 120 and with an insect screen 160 installed on the first housing 120. The insect screen 160 is generally cylindrical, with its axial end held by a first housing insect screen retaining groove 123 of the first housing 120. The axial end of the insect screen 160 faces the ventilation window 131. However, the axial end of the ventilation window 131 extends further than the insect screen 160, facing the outer periphery of the first housing 120. In this example, the insect screen 160 is a mesh made of non-conductive stainless steel with a diameter of approximately 0.1 mm and a mesh size of approximately 60. Therefore, the mesh spacing is approximately 0.2 to 0.3 mm.

[0041] As described above, the first housing 120 is positioned opposite the axial end of the ventilation window 131. A first housing air guide 124 is formed at the position opposite the ventilation window 131, guiding the inflow air (smoke) from the ventilation window 131 and the outflow air toward the ventilation window 131. On the outer periphery of the first housing 120, at the end opposite the ventilation window 131 closer to the axial direction than the first housing insect screen retaining groove 123, is a tapered portion 125 with a diameter decreasing toward the axial direction. The first housing air guide 124 is composed of two portions: a first housing air guide first portion 1241 and a second housing air guide second portion 1242. The first housing air guide first portion 1241 is positioned radially outside the first housing insect screen retaining groove 123 opposite the ventilation window 131. Furthermore, the first housing air guide first portion 1241 guides the air at the axial end of the ventilation window 131 toward the tapered portion 125. On the other hand, the second part 1242 of the first housing air guide is located radially inside the insect screen retaining groove 123 of the first housing and faces the ventilation window 131. Moreover, the second part 1242 of the first housing air guide is formed on the conical part 125 to guide air to flow along the outer periphery of the conical part 125.

[0042] Next, use Figure 5 and Figure 6 To illustrate the third housing 150. Figure 5 Only the appearance of the third housing 150, including the substrate assembly 140, is shown. Figure 6A cross-section showing the third housing 150 remaining within the second housing 130 is shown. A third housing air guide 155 is also formed on the outer periphery of the third housing 150, guiding the airflow between the ventilation window 131 and the detection space 132. With the first housing 120 and the third housing 150 contained inside the second housing 130, one axial end of the second portion 1242 of the first housing air guide aligns with the other axial end of the third housing air guide 155. Figure 6 As shown, one end of the third housing air guide 155 is bent axially to form a labyrinth wall. In addition to guiding airflow as described above, it also has a light-shielding function, blocking external light from entering the detection space 132 through the ventilation window 131. Of course, as light-shielding, it is not required to achieve 100% blocking of external light. In this disclosure, blocking external light means blocking the amount of external light that would adversely affect the light receiving element 152.

[0043] The light-emitting element 151 disposed inside the third housing 150 is an LED that projects light toward the smoke detection space 132, for example, projecting light with a light intensity of about 20 milliwatts. Figure 6 and Figure 11 As shown, in the third housing 150, a light-emitting holding groove 156 is formed between the light-emitting element 151 and the detection space 132 to allow light projected from the light-emitting element 151 to pass through. The light-emitting holding groove 156 has a width of about 4 mm, and the light from the light-emitting element 151 reaches the detection space 132 from the light-emitting holding groove 156.

[0044] The light-receiving element 152 is a photodiode that detects the scattered light when smoke enters the detection space 132 and light projected from the light-emitting element 151 diffuses through the smoke. Figure 6 and Figure 11 As shown, in the third housing 150, a light-receiving holding groove 157 is formed between the light-receiving element 152 and the detection space 132, allowing light emitted in the detection space 132 to pass through towards the light-receiving element 152. The light-receiving holding groove 157, like the light-emitting holding groove 156, has a groove width of approximately 4 mm. It should be noted that the light-receiving element 152 is positioned separate from the optical axis of the light-emitting element 151. That is, the light-receiving element 152 does not directly detect the projected light from the light-emitting element 151, but rather detects the scattered light diffused by the smoke. Since the scattered light diffused by the smoke is weak, the output signal of the light-receiving element 152 is a weak current of approximately a few nanoamps.

[0045] Since the third housing 150 is made of a conductive resin material, the light-emitting element 151 is held in a light-emitting element support 153 made of ABS resin, which is a non-conductive resin material. Through this light-emitting element support 153, the light-emitting element 151 is electrically insulated from the third housing 150 and the substrate assembly 140. Similarly, the light-receiving element 152 is also held in a light-receiving element support 154 made of ABS resin, which is also a non-conductive resin material, and is electrically insulated from the third housing 150 and the substrate assembly 140. The light-emitting element support 153 is held in the aforementioned light-emitting holding groove 156. Furthermore, the light-receiving element support 154 is held in the light-receiving holding groove 157.

[0046] As described above, the substrate assembly 140 forms part of the third housing 150. The substrate assembly 140 is disposed on the opening surface of the third housing 150, and the opening surface is closed by the substrate assembly 140, thereby constituting the third housing 150. Figure 5 As shown, the substrate assembly 140 houses the control unit 141, the transmitter 142, the output antenna 143, the notification light 146, and the power connector 145. The control unit 141 is a single-chip microcomputer including a CPU that controls the light-emitting element 151 and the light-receiving element 152, and it has an internal temperature sensor. In addition, the control unit 141 also monitors the remaining power of the battery 121.

[0047] The transmitting unit 142 is a communication module that transmits signals to the outside and has a transmitting circuit inside. The transmitted signals include a stable signal and a notification signal. The notification signal is a signal indicating the possibility of a fire, transmitted by the control unit 141 if the signal detected by the light receiving element 152 is above a predetermined threshold. The notification light 146 is an LED that illuminates when the notification signal is output. As described above, the smoke detector 100 of this example is disposed in an enclosed space such as a control box 200, but since it can be seen through the gaps in the control box 200, the occurrence of a fire can be notified to the surrounding area via the notification light 146.

[0048] The output antenna 143 is a monopole antenna using copper wire insulated with polyethylene resin. The length of the output antenna 143 is determined by the output frequency. To improve diffraction and reachability, the wireless transmission frequency used in the factory is lower than the frequency (2.4 GHz) used in Wi-Fi and Bluetooth (trademarked). The frequency used in this example is, for example, 920 MHz. A lower frequency results in a longer wavelength of the radio wave, requiring careful consideration of the length and surface area of ​​the output antenna 143. In this example, the length of the output antenna 143 is set to approximately 80 mm.

[0049] The substrate assembly 140 has a four-layer structure separated by three insulating substrates. The first layer is a mounting surface 1401 for mounting the control unit 141 (CPU, etc.), the transmitter 142 (communication module), the notification lamp 146, and the power connector 145. The second layer is a power conductor film. In this second layer, the power conductor film is formed by copper foil with a thickness of about 18 micrometers. The power conductor film is electrically connected to the positive terminal of the battery 121 through the power connector 145, supplying power from the positive terminal of the battery 121. The light-emitting element 151, the light-receiving element 152, and the notification lamp 146 are also electrically connected to this power conductor film 1403, receiving power from it.

[0050] The third layer of the substrate assembly 140 is a grounding conductor film. This grounding conductor film is made of a conductive metal material such as copper foil, and its thickness is approximately 18 micrometers, the same as that of the power conductor film. Since the grounding conductor film is formed on almost the entire surface of the substrate assembly 140, the third housing 150 has a grounding conductor film extending on one side. Therefore, the third housing 150, including the substrate assembly 140, functions as a shielding housing that isolates the interior from electromagnetic noise. That is, a space is formed by the grounding conductor film of the substrate assembly 140 and the conductive third housing 150, and this enclosed space becomes a shielding space, shielding the interior from electromagnetic waves. The grounding conductor film is electrically connected to the negative terminal of the battery 121 via the power connector 145.

[0051] The fourth layer of the substrate assembly 140 is a circuit surface for mounting an amplifier circuit that amplifies the signal detected by the light-receiving element 152. On this circuit surface, in addition to the amplifier circuit, a power supply conductor film is printed with positive wiring connecting to the positive terminals of the light-emitting element 151 and the light-receiving element 152. Additionally, a ground conductor film is printed on this circuit surface with negative wiring connecting to the negative terminals of the light-emitting element 151 and the light-receiving element 152. Furthermore, signal lines for the light-receiving element 152 are printed on the circuit surface 1404. Because the fourth layer is located inside the third housing 150, which serves as a closed container, electromagnetic wave shielding is effectively achieved for the amplifier circuit and the like.

[0052] Figures 7 to 10 The second housing 130 is shown. Figures 7 to 9 The insect net 160 is shown to be held in the second housing 130. Figure 9 The cross-section shown is located at one end closer to the axial direction than ventilation window 131. Figure 10A cross-section of the ventilation window 131 portion is shown. In the second housing 130, a detection space 132 for detecting smoke by the detection elements (light-emitting element 151 and light-receiving element 152) is formed at the other end of the bottom 134 along the axial direction. In relation to the third housing 150, this detection space 132 is formed at one end of the axial direction of the third housing 150. In the second housing 130, a second housing air guide 137 is integrally formed to surround the detection space 132. With the third housing 150 held inside the second housing 130, the other end of the axial direction of the second housing air guide 137 coincides with one end of the axial direction of the third housing air guide 155. Therefore, the second housing air guide 137 is also curved to form a labyrinth wall. Similar to the third housing air guide 155, the second housing air guide 137, in addition to guiding airflow, also has a light-shielding function to block external light from the ventilation window 131 from entering the detection space 132. The light-blocking function does not require 100% blocking of external light, which is the same as the third housing air guide 155 mentioned above.

[0053] On the second housing 130, a second housing insect-proof net retaining groove 138 is formed to retain one axial end of the insect-proof net 160. Therefore, one axial end of the insect-proof net 160 is inserted into and retained in the second housing insect-proof net retaining groove 138. As described above, the other axial end of the insect-proof net 160 is inserted into and retained in the first housing insect-proof net retaining groove 123. Therefore, the insect-proof net 160 is held from both axial sides. In relation to the cylindrical portion 135 of the second housing 130, the insect-proof net 160 is disposed on the radial inner circumference of the cylindrical portion 135. Figure 8 and Figure 10 As shown, strips 139 are formed on the cylindrical portion 135 between ventilation windows 131. In other words, the ventilation windows 131 are the spaces between adjacent strips 139. Furthermore, an insect-proof net holding portion 1391 protruding toward the insect-proof net 160 is formed on the inner circumferential surface of the strip 139. In relation to the air guide portions, the insect-proof net 160 is disposed radially outside the second portion 1242 of the first housing air guide portion, the third housing air guide portion 155, and the second housing air guide portion 137. Therefore, the radially inner side of the insect-proof net 160 is held by the second portion 1242 of the first housing air guide portion, the third housing air guide portion 155, and the second housing air guide portion 137. Moreover, the radially outer side of the insect-proof net 160 is held by the first portion 1241 of the first housing air guide portion and the insect-proof net holding portion 1391 of the second housing 130.

[0054] Next, the operation of the smoke detector 100 in this example will be described. The smoke detector 100 is installed in a high-fire-risk area of ​​the factory, namely the top plate 201 of the control box 200. The control unit 141 periodically energizes the light-emitting element 151 to make it emit light. For example, at a timer of once every 10 seconds, the light-emitting element 151 is energized for about 20 milliseconds. This saves power to the battery 121. In addition, the light receiving element 152 is also activated in conjunction with the timer for emitting light from the light-emitting element 151. When there is no fire, smoke will not flow into the detection space 132, and the light from the light-emitting element 151 will not be scattered. Furthermore, light from the outside is blocked by the labyrinth walls of the second housing air guide 137 and the third housing air guide 155. Therefore, the light receiving element 152, which is activated at the predetermined time, will not detect light.

[0055] Thus, the light-emitting element 151 and the light-receiving element 152 periodically determine whether there is smoke. The control unit 141 also periodically sends information from the transmitting unit 142 when no fire has occurred. This periodically transmitted information includes a unique number assigned to each smoke detector 100, information indicating the remaining power of the battery 121, temperature information from the temperature sensor on the CPU of the control unit 141, and signal information from the light-receiving element 152. When no fire has occurred, the signal from the light-receiving element 152 is below a predetermined threshold.

[0056] The control unit 141 transmits periodic information from the transmitting unit 142 to an external receiver. Specifically, it transmits signals from the output antenna 143 to a receiver configured on the production line. At this time, since the third housing 150 functions as grounding, the antenna efficiency of the output antenna 143 can be improved. Furthermore, because the output antenna 143 is separated from the third housing 150 by the straight section, electromagnetic coupling between the third housing 150 and the output antenna 143 is difficult to occur. This also improves the efficiency of the output antenna 143.

[0057] In the event of a fire, smoke rises in the control box 200. The rising smoke separates from the ceiling 201 by about 2 centimeters and flows along the ceiling 201. If a fan 203 is installed in the control box 200, the smoke is drawn towards the fan 203 along the ceiling 201.

[0058] The smoke detector 100 detects smoke because smoke flows into the detection space 132. When the detection space 132 is filled with smoke, light from the light-emitting element 151 shines on the smoke and is scattered. The scattered light generated by the smoke is detected by a light-receiving element 152 that is activated at the same time as the light-emitting element 151. The light-receiving element 152 outputs a weak but detectable detection signal of about a few nanoamps. This detection signal is amplified by an amplifier circuit and then input to the control unit 141. Through this signal, the smoke detector 100 detects the occurrence of a fire.

[0059] At this time, when electromagnetic waves are applied to the light receiving element 152 and the amplification circuit, electromagnetic noise may be generated, causing the smoke detector 100 to react incorrectly. However, in the smoke detector 100 of this example, the shielding space is formed by a third housing 150 made of conductive resin material, including the substrate assembly 140. Moreover, the light receiving element 152 and the amplification circuit are disposed within this shielding space. Therefore, the light receiving element 152 and the amplification circuit are less susceptible to interference from electromagnetic waves.

[0060] When the signal from the light receiving element 152 exceeds a predetermined threshold, the control unit 141 determines that a fire has occurred and sends a notification signal from the transmitting unit 142. The notification light 146 then flashes. However, to prevent the transmission of erroneous information, the notification signal can also be lengthy. For example, since the presence of smoke is periodically checked, a notification signal can be issued only after three or more consecutive signals exceeding the threshold are received. Alternatively, the notification signal can be determined by combining the signal from the temperature sensor included in the CPU of the control unit 141.

[0061] The above describes the operation of the smoke sensor 100. However, in this example, since it is easy to direct smoke into the detection space 132 of the smoke sensor 100, the following uses... Figure 14 To explain in detail the airflow from the upstream to the downstream side.

[0062] The control box 200 configured for the smoke detector 100 in this example is smaller in volume than buildings such as factories and is prone to filling with smoke. Although the smoke rises to a position close to the ceiling 201, the air stagnates directly below the ceiling 201. Therefore, the main flow of smoke will be about 2 cm away from the ceiling 201. This is the location of the axial side opening of the ventilation window 131 of the smoke detector 100.

[0063] In this example, the detection space 132 is formed near the bottom 134 of the second housing 130. Axially, it is separate from the first housing 120, which includes the base 110 fixed to the top plate 201. Since the axial length of the smoke sensor 100 in this example is approximately 50 mm, it is some distance from the main source of smoke. However, in this example of the smoke sensor 100, because the ventilation window 131 opens at the main source of smoke, the smoke can be smoothly guided into the detection space 132.

[0064] When a fan 203 is installed in the control box 200, a constant-direction airflow is generated by the fan 203. Although smoke flows into the smoke sensor 100 from the ventilation window 131, which opens on the upstream side of the airflow, it encounters significant flow resistance due to the insect screen 160. In this example, to mitigate the flow resistance of the insect screen 160, the area of ​​the ventilation window 131 is set as large as possible. That is, the ventilation window 131 extends from near the bottom 134 of the second housing 130 on one axial end to the portion opposite to the first housing 120 on the other axial end. Moreover, by arranging the insect screen 160 at the opening of the ventilation window 131, the opening area of ​​the ventilation window 131 is increased, as is the area of ​​airflow passing through the insect screen 160. Specifically, the second housing insect screen retaining groove 138 is formed at approximately the same position as one axial end of the ventilation window 131, and one axial end of the ventilation window 131 is approximately aligned with one axial end of the insect screen 160. On the other axial end, the ventilation window 131 extends further than the insect screen 160. However, a first housing insect screen retaining groove 123 is also formed on the other end of the first housing 120. Therefore, the axial length of the insect screen 160 is longer than that of the detection space 132.

[0065] For example, when the axial length of the portion corresponding to the detection space 132 is approximately 11 mm, the axial length of the ventilation window 131 is also approximately 11 mm when the opening of the ventilation window 131 is aligned with the detection space 132. The axial length of the smoke sensor 100 is approximately 50 mm in this example, but even considering the base 110 of the first housing 120 and the bottom 134 of the second housing 130, the ventilation window 131 in this example can still be ensured to have an axial length of approximately 30 mm. Therefore, compared to the example where the opening is only at the portion corresponding to the detection space 132, the ventilation window 131 in this example allows the opening area through which air can pass to increase by up to 2.7 times. However, even if the opening area is not increased by 2.7 times, the airflow guiding effect can still be fully utilized. For example, even if the axial length of the ventilation window 131 is only half of the 30 mm in this example, i.e., 15 mm, and the opening area is only increased by 1.4 times, the airflow velocity required for the same flow rate can be reduced by 0.73 times.

[0066] For example, suppose the required airflow velocity for a given amount of air to pass through ventilation window 131 is 1 meter per second. With the insect screen 160 set to 60 meshes and a mesh gap of approximately 0.2 millimeters, the pressure loss when air flows at a velocity of 1 meter per second is 6.3 Pascals. On the other hand, even using the same insect screen 160, if the flow velocity is reduced to 0.73 meters per second, the pressure loss decreases to 3.4 Pascals. Thus, the pressure loss is reduced by 0.55 times. Assuming the airflow velocity is 1 meter per second, if the axial length of ventilation window 131 is shortened to 11 millimeters, air cannot pass through the insect screen 160. Even in this case, setting the axial length to only 1.4 times, or 15 millimeters, allows air to be directed to the detection space 132. In the ventilation window 131 of this example, since it is 30 millimeters, the effect of directing air to the detection space 132 is even more significant.

[0067] Thus, the ventilation window 131 in this example is elongated in the axial direction and has an increased opening area, thereby facilitating the introduction of smoke into the detection space 132. Furthermore, as mentioned above, the ventilation window 131 in this example also has an opening approximately 20 mm from the top plate 201 corresponding to the main airflow direction. This also facilitates the introduction of smoke from the ventilation window 131 into the detection space 132.

[0068] Furthermore, air flowing into the ventilation window 131 from near the top plate 201 faces the conical portion 125 of the first housing 120. Therefore, it easily flows along the conical portion 125 towards the detection space 132. And, as... Figure 11 and Figure 12As shown, the outer periphery of the first housing 120 and the outer periphery of the third housing 150 are smooth and continuous. Therefore, air flowing along the tapered portion 125 of the first housing 120 flows directly along the outer periphery of the third housing 150. Furthermore, the outer periphery of the third housing 150 is hemispherical, with its central portion corresponding to the detection space 132. This shape of the outer periphery of the third housing 150 also facilitates airflow within the detection space 132.

[0069] In the smoke detector 100 of this example, in addition to the above-described structure, air guides are formed on the outer periphery of the first housing 120, the outer periphery of the third housing 150, and the interior of the second housing 130. Furthermore, the second portion 1242 of the first housing air guide, the third housing air guide 155, and the second housing air guide 137 are continuous and integrally formed. The first portion 1241 of the first housing air guide is formed at the opposite end of the axial direction of the ventilation window 131. Therefore, air flowing in from the ventilation window 131 is also guided to the insect screen 160 side by the first portion 1241 of the first housing air guide. Moreover, air passing through the insect screen 160 is guided by the second portion 1242 of the first housing air guide, the third housing air guide 155, and the second housing air guide 137, thereby being guided to the detection space 132. Through the guidance of the air guides, the airflow becomes stable. With this effect, smoke also easily flows into the detection space 132.

[0070] The above configuration describes airflow from ventilation window 131 toward detection space 132, but the airflow from detection space 132 toward the downstream side of ventilation window 131 is also the same. Figure 14 The diagram shows a decrease in air velocity and an increase in static pressure on the upstream side of the airflow. As mentioned above, although a pressure loss occurs when passing through the insect screen 160, in this example, the air flows through the insect screen 160 and into the windward section because the static pressure at the ventilation window 131 upstream of the airflow exceeds the pressure loss.

[0071] In the ventilation window 131 downstream of the airflow, a negative pressure exists. This negative pressure draws air from the detection space 132 towards the ventilation window 131 downstream of the airflow. Furthermore, in this example, one axial end of the ventilation window 131 is located at the hemispherical bottom 134. Therefore, the axial end of the ventilation window 131 bends radially inward. This bend easily generates negative pressure in the ventilation window 131 downstream of the airflow. In particular, because this bend is located at one axial end and close to the detection space 132, air from the detection space 132 is easily drawn downstream of the airflow.

[0072] In addition to generating airflow from the ventilation window 131 toward the detection space 132, the airflow also generates airflow along the cylindrical portion 135 of the second housing 130 around the outer periphery of the second housing 130. The airflow velocity increases at a location downstream of the second housing 130. At this location, the insect-proof mesh retaining portion 1391 formed on the inner circumferential surface of the strip 139 also contributes to stabilizing the airflow. This is because the insect-proof mesh retaining portion 1391, due to its shape protruding toward the insect-proof mesh 160, has an effect of suppressing the entrainment of airflow around the inner periphery of the strip 139. By forming the insect-proof mesh retaining portion 1391, the negative pressure at the ventilation window 131 becomes stable downstream of the airflow, facilitating the extraction of air from the detection space 132 downstream.

[0073] The ease of air extraction on the downstream side of the airflow means that air can easily flow into the detection space 132 from the upstream side of the airflow. This has the following effects: First, to improve airflow, the area of ​​the ventilation window 131 is increased to suppress the flow velocity required to pass through the insect screen 160. Additionally, it has the following effects: the airflow is guided by the first housing air guide 124 (first housing air guide first portion 1241 and first housing air guide second portion 1242), the second housing air guide 137, and the third housing air guide 155, thereby making the airflow smoother. These effects are not limited to the upstream side of the airflow. The downstream side of the airflow also facilitates smoother airflow. Corresponding to these downstream effects, the smoke sensor 100 of this example easily introduces smoke into the detection space 132.

[0074] Since the smoke detector 100 in this example also has characteristics regarding the configuration positions of the notification light 146 and the insect screen 160, the characteristics of the notification light 146 will be described next. Figure 12 As shown, the notification light 146 is disposed on the inner periphery of the insect screen 160, and when illuminated, it directs red light toward the insect screen 160. Therefore, when the notification light 146 is illuminated, the light is reflected by the insect screen 160, thereby diffusing over a wider range (wider angle). With the smoke detector 100 disposed inside the control box 200, the light from the notification light 146 leaks to the outside through gaps in the fan 203 or doors, etc. Therefore, the light from the notification light 146 diffuses at a wider angle, and the light leaks more easily to the outside of the control box 200, thereby improving visibility.

[0075] Next, a variation of the smoke sensor 100 of this example will be described. In the example above, the bottom 134 of the second housing 130 is hemispherical. This shape is desirable because it facilitates the generation of negative pressure on the downstream side of the airflow. However, by bending the bottom 134 and placing one axial end of the ventilation window 131 at the bend, the negative pressure on the downstream side of the airflow can be utilized. Therefore, the shape of the bottom 134 is not limited to a hemispherical shape; it can also be tapered in the circumferential direction.

[0076] In the above example, since the detection element is a light-emitting element 151 and a light-receiving element 152, it is necessary to prevent external light from entering the detection space 132. Therefore, the second housing air guide 137 and the third housing air guide 155 have a light-shielding function as labyrinth walls. However, when the detection element is a gas sensor, it is not necessary for the second housing air guide 137 and the third housing air guide 155 to have a light-shielding function. The necessary function of the first housing air guide 124, the second housing air guide 137, and the third housing air guide 155 is to rectify the airflow between the ventilation window 131 and the detection space 132.

[0077] In the above example, the smoke detector 100 includes an insect screen 160. The above example assumes the presence of the insect screen 160 and employs a structure including a first housing insect screen retaining groove 123, a second housing insect screen retaining groove 138, and an insect screen retaining part 1391. Furthermore, the placement position of the notification light 146 is defined based on the presence of the insect screen 160. However, if the detection element is a gas sensor, the insect screen 160 is not necessarily required.

[0078] In the above example, the smoke detector 100 is housed in an enclosed space such as a control box 200, and therefore does not have a speaker. However, a speaker can also be used. If a speaker is included, the control unit 141 can also activate the speaker while the notification light 146 flashes. This allows the surrounding area to be notified of the occurrence of a fire. Furthermore, to achieve a compact and lightweight design, the smoke detector 100 in this example only has a signal transmitting unit 142 and does not have a receiving unit. However, a receiving function can be included. If the smoke detector 100 has a receiving function, it can also receive notification signals from other smoke detectors 100 located nearby. In this case, when a notification signal from another smoke detector 100 is received, the speaker can be activated, or the notification LED 146 can be flashed. Additionally, the receiving function can be used to receive signals from an externally configured management server. For example, signals that switch communication channels and frequency bands can be received, allowing the settings of the smoke detector 100 to be changed. In this case, the settings are changed via the control unit 141.

[0079] Furthermore, in the example described above, the control unit 141 determines that a fire has occurred and sends a notification signal when a fire is likely to occur. It is desirable that the notification signal can be detected near the signal from the light receiving element 152. However, the smoke detector 100 may always send a signal only at a predetermined time. In this case, the signals from each smoke detector 100 are received by receivers configured on the production line and sent to a management server configured at a different location from the production line via communication lines such as the Internet and / or a cloud system with an intranet. The fire is then determined by the management server. If the notification signal is not detected by the smoke detector 100, the notification light 146 is not needed.

[0080] Furthermore, in the above embodiments, an example of using the sensor of this disclosure as a smoke detector 100 in a factory was described. This is an example of a use requiring a rapid influx of smoke, which is also the intended use of the sensor of this disclosure. However, the smoke detector 100 can also be used in other applications. It can be used not only in factories but also for environmental monitoring in remote areas. For example, it can also be used in substations, inside containers of ships or trucks, warehouses, and boxes containing photovoltaic power generation batteries. Depending on the usage, the base 110 can be screwed to the ceiling of a building. In addition, depending on the usage, the base 110 is sometimes fixed to the wall of a building. Therefore, the function of the smoke detector 100 in this disclosure is not limited to use in factories, but also means that it can be widely used as a device for sensing smoke.

[0081] Furthermore, in the above embodiments, an example of using the sensor disclosed herein as a smoke sensor 100 was described. The smoke sensor 100 is an example of a sensor and represents a desired application. However, the detection element is not limited to the light-emitting element 151 and the light-receiving element 152. In addition, detection elements that sense odors, vibrations, sounds, etc., can also be used. For example, detection elements that detect carbon dioxide or odors can be used to detect the smell of burning grease in motors installed on the production line, thereby detecting abnormalities in the production line. Furthermore, when a motor installed on the production line malfunctions, it may vibrate violently or emit a loud abnormal noise. By detecting these vibrations or abnormal noises with a detection element, abnormalities in the production line can be detected in advance.

[0082] The sensor disclosed herein can be used as a wireless Internet of Things (IoT) sensor for a wide range of applications. In this case, it can also be used as a sensor in home appliances or wearable devices.

[0083] Furthermore, the size and materials of the above embodiment are merely examples. For instance, the third housing 150 is formed by injection molding from a conductive resin material in the above example, but it can also be formed from a conductive metal material. Examples of metal materials include copper, aluminum, and iron. Alternatively, the third housing 150 can be formed from a non-conductive resin material, with a conductive metal plated or sprayed onto its surface. Similarly, the insect net 160 is also made from non-conductive stainless steel wire in the above example, but it can also be made from a non-conductive resin material.

[0084] (The public disclosure of technological ideas)

[0085] This specification discloses the ideas of several techniques described in the following list. Some items are sometimes described by alternatively referring to a multiple dependent form of an item preceding a subsequent item. Furthermore, some items are sometimes described by referring to a multiple dependent form of an item of another multiple dependent form. Items described in these multiple dependent forms define the ideas of several techniques.

[0086] (Technological Ideas 1)

[0087] A sensor, wherein the sensor comprises:

[0088] A first housing (120) is installed on the part to be detected;

[0089] A second housing (130) having an axially extending cylindrical portion (135), a bottom (134), and an opening (136), the bottom being formed at one axial end of the cylindrical portion and the opening being formed at the other axial end of the cylindrical portion; and

[0090] A third housing (150) holds a detection element, a control unit (141), and a transmitting unit (142). The control unit controls the detection element, and the transmitting unit transmits a signal detected by the detection element to the outside.

[0091] The first housing is held inside the second housing on the opening side of the second housing.

[0092] The third housing is held inside the second housing at one axial end of the first housing.

[0093] The second housing has a detection space formed on one axial end side of the third housing for the detection element to perform detection.

[0094] In the cylindrical portion of the second housing, a plurality of axially extending ventilation windows (131) are formed in the circumferential direction. One axial end of each ventilation window corresponds to the position of the detection space, and the other axial end of each ventilation window corresponds to the position of the first housing.

[0095] Air guides (124, 137, 155) are formed in the first housing, the second housing, and the third housing. The air guides direct air from the upstream side of the airflow through the ventilation window to the detection space, and direct air from the detection space to the downstream side of the airflow through the ventilation window.

[0096] (Technological Ideas 2)

[0097] According to the sensor described in Technological Idea 1, the air guide portion formed in the second housing and the third housing has a light-shielding function to block external light from the ventilation window from entering the detection space.

[0098] (Technological Ideas 3)

[0099] According to the sensor described in Technological Idea 1 or Technological Idea 2, an insect-proof mesh (160) is disposed on the radially inner side of the cylindrical portion of the second housing to prevent foreign objects from entering the detection space through the ventilation window.

[0100] One axial end of the insect net is held in the second housing, and the other axial end of the insect net is held in the first housing.

[0101] (Technological Ideas 4)

[0102] According to the sensor described in Technological Idea 1 or Technological Idea 2, an insect-proof net is disposed on the radially inner side of the cylindrical portion of the second housing to prevent foreign objects from entering the detection space through the ventilation window.

[0103] The air guide portion of the first housing has a first housing air guide portion first portion (1241) disposed on the radial outer side of the insect net, and a first housing air guide portion second portion (1242) disposed on the radial inner side of the insect net.

[0104] (Technological Ideas 5)

[0105] According to the sensor described in Technique 4, the first housing air guide portion of the first housing, the air guide portion of the second housing, and the air guide portion of the third housing are continuous and integral in shape.

[0106] (Technological Ideas 6)

[0107] According to any one of the technical ideas 3 to 5, in the cylindrical portion of the second housing, an insect-proof net retaining portion (1391) protruding toward the insect-proof net is formed on the inner circumferential surface of the strip portion (139) located between the ventilation windows.

[0108] (Technological Ideas 7)

[0109] According to any one of technical ideas 3 to 6, the sensor, wherein the third housing also holds a notification light (146), which illuminates to indicate that the detection element has detected the sensor.

[0110] When the notification light is turned on, it shines light from the inner periphery of the insect-proof net towards the insect-proof net.

[0111] (Technological Ideas 8)

[0112] According to any one of the technical ideas 1 to 7, in the ventilation window, an axial end portion is formed at the bottom of the second housing, and the bottom is radially inward at the axial end portion where the ventilation window is formed.

Claims

1. A perceptron, wherein, The sensor has the following features: A first housing, which is installed at the part being tested; A second housing has an axially extending cylindrical portion, a bottom, and an opening, the bottom being formed at one axial end of the cylindrical portion and the opening being formed at the other axial end of the cylindrical portion. as well as A third housing holds a detection element, a control unit, and a transmitting unit. The control unit controls the detection element, and the transmitting unit transmits the signal detected by the detection element to the outside. The first housing is held inside the second housing on the opening side of the second housing. The third housing is held inside the second housing at one axial end of the first housing. The second housing has a detection space formed on one axial end side of the third housing for the detection element to perform detection. In the cylindrical portion of the second housing, a plurality of ventilation windows extending axially are formed in the circumferential direction. One axial end of each ventilation window corresponds to the position of the detection space, and the other axial end of each ventilation window corresponds to the position of the first housing. Air guides are formed in the first housing, the second housing, and the third housing. The air guides direct air from the upstream side of the airflow through the ventilation window to the detection space, and direct air from the detection space to the downstream side of the airflow through the ventilation window.

2. The sensor according to claim 1, wherein, The air guides formed in the second housing and the third housing have a light-shielding function to block external light from entering the detection space from the ventilation window.

3. The sensor according to claim 1, wherein, An insect-proof mesh is disposed on the radially inner side of the cylindrical portion of the second housing to prevent foreign objects from entering the detection space through the ventilation window. One axial end of the insect net is held in the second housing, and the other axial end of the insect net is held in the first housing.

4. The sensor according to claim 1, wherein, An insect-proof mesh is disposed on the radially inner side of the cylindrical portion of the second housing to prevent foreign objects from entering the detection space through the ventilation window. The air guide portion of the first housing has a first housing air guide portion first portion disposed on the radial outer side of the insect net, and a second housing air guide portion second portion disposed on the radial inner side of the insect net.

5. The sensor according to claim 4, wherein, The first housing air guide portion of the first housing, the air guide portion of the second housing, and the air guide portion of the third housing are continuous and integral in shape.

6. The sensor according to claim 3 or 4, wherein, In the cylindrical portion of the second housing, an insect-proof net retaining portion protruding toward the insect-proof net is formed on the inner circumferential surface of the strip located between the ventilation windows.

7. The sensor according to claim 3 or 4, wherein, The third housing also houses a notification light, which illuminates to indicate that the detection element has detected the data. When the notification light is turned on, it shines light from the inner periphery of the insect-proof net towards the insect-proof net.

8. The sensor according to claim 1, wherein, In the ventilation window, one axial end portion is formed at the bottom of the second housing, and the bottom bends radially inward at the axial end portion where the ventilation window is formed.

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