Smoke alarm capable of adjusting threshold value according to received illumination intensity

Abstract

The utility model relates to the technical field of smoke alarms, in particular to a smoke alarm capable of adjusting a threshold value according to received illumination intensity, which comprises a light source generating device, a light sensor, a light shielding body positioned on the light source generating device and a controller, and the working process of the smoke alarm is divided into a self-checking process and a monitoring process. In the monitoring process, the shading body is in a first state for preventing the light sensor from directly receiving light rays generated by the light source generating device, and in the self-checking process, the shading body is in a second state for not influencing the light sensor to directly receive the light rays generated by the light source generating device. The controller adjusts a first threshold value capable of triggering an alarm in the monitoring process according to the light intensity received by the light sensor in the self-checking process, controls the state of the shading body through the controller, achieves self-checking of the smoke alarm, and adjusts a light intensity threshold value for triggering the alarm in the monitoring process according to the light intensity received in the self-checking process. And an accurate smoke detection process is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of smoke alarms, in particular to a smoke alarm capable of adjusting a threshold value according to received light intensity. Background Art

[0002] Smoke alarms are used in fire protection projects and are usually installed on the inner top wall of a room. When the smoke generated in the early stage of a fire is heated and moves upward to the inside of the smoke alarm, the smoke alarm will sound, thereby alerting people in time to escape or deal with the fire in time.

[0003] Most of the existing smoke alarms are photoelectric smoke alarms, and their working principle is that a light-emitting device, a photosensor, a light shield and a controller are installed inside the detection room. Under normal circumstances, the light emitted by the light-emitting device cannot be received by the photo sensor due to the blocking of the light shield. When smoke enters the inside of the smoke alarm, the light emitted by the light-emitting device can reach the photo sensor after reflection. The photo sensor converts the received light signal into an electrical signal and sends it to the controller. After the controller determines that the current received light intensity reaches the threshold, the controller controls the alarm device to trigger the alarm. However, the traditional smoke alarm device has a defect that the light intensity threshold for triggering the alarm is a fixed value. When the surface of the light-emitting device or the photo sensor is covered with dust, the light received by the photo sensor will become weaker. When the power supply is insufficient, the light intensity emitted by the light-emitting device is also weak, so that the light intensity received by the photo sensor is also weakened accordingly, which can easily lead to the alarm not being triggered because the light intensity received by the photo sensor does not reach the threshold after smoke enters the smoke alarm.

[0004] Of course, the prior art also has corresponding solutions to adjust the light intensity threshold that can trigger an alarm. The main principle is to add a photosensor that can directly receive the light source generating device, and adjust the light intensity threshold that triggers the alarm by the light intensity received in real time by the added photosensor. Although this method can adjust the threshold that triggers the alarm to a certain extent, the error is large. The reason is that it cannot ensure that the dust adhesion on the surfaces of the two photosensors is consistent, so sometimes it is impossible to accurately adjust the threshold. Utility Model Content

[0005] The utility model provides a smoke alarm which adjusts a threshold value according to the received light intensity. The smoke alarm can switch between a self-checking process and a monitoring process by adjusting the state of a light shielding body, and adjusts the light intensity threshold value which can trigger an alarm in the monitoring process according to the light intensity received in the self-checking process.

[0006] The technical problem solved by the utility model is achieved by the following technical solutions:

[0007] A smoke alarm that adjusts the threshold according to the received light intensity, comprising a light source generating device for generating light, a light sensor for receiving the light emitted by the light source generating device, a light-shielding body between the light source generating device and the light sensor, and a controller for emitting an alarm signal when the light intensity received by the light sensor exceeds the first threshold during the smoke monitoring process. The working process of the smoke alarm is divided into a self-check process and a monitoring process. During the monitoring process, the light-shielding body is in a first state that prevents the light sensor from directly receiving the light generated by the light source generating device. During the self-check process, the light-shielding body is in a second state that does not affect the light sensor directly receiving the light generated by the light source generating device. The first state and the second state of the light-shielding body are controlled and operated by the controller, and the controller adjusts the first threshold that can trigger an alarm during the monitoring process according to the light intensity received by the light sensor during the self-check process.

[0008] Preferably, the controller realizes the switching between the self-check process and the monitoring process by adjusting the relative positions of the light-shielding body, the light source generating device, and the light sensor.

[0009] Preferably, the light-shielding body can be magnetically adsorbed and is mounted on a base. A guide rod passing through the light-shielding body is provided on the base. A spring is sleeved outside the guide rod between the light-shielding body and the base. An electromagnet is provided on the base and below the light-shielding body. When the controller controls the electromagnet to be energized, the light-shielding body is adsorbed to the electromagnet, and at this time the light-shielding body is in the second state. When the controller controls the electromagnet to be de-energized, the light-shielding body disengages from the electromagnet under the support of the spring, and at this time the light-shielding body is in the first state.

[0010] Preferably, the controller controls the smoke alarm to switch between the self-check process and the monitoring process according to the clock signal of the clock module.

[0011] Preferably, when the smoke alarm is in the self-check process, if the light intensity received by the light sensor is less than the second threshold, the controller emits an alarm signal. If the light intensity received by the light sensor is greater than the second threshold, the controller adjusts the size of the first threshold according to the received light intensity.

[0012] Preferably, it further includes an alarm device. When the alarm device receives the alarm signal from the controller, the alarm device emits an alarm.

[0013] Preferably, the light-shielding body realizes the switching between the first state and the second state through the change of its own transparency.

[0014] The beneficial effects of the present utility model are: by controlling the state of the light-shielding body by the controller, the self-check of the smoke alarm is realized, and the light intensity threshold for triggering an alarm during the monitoring process is adjusted according to the light intensity received during the self-check process, so as to realize an accurate smoke detection process.

[0015] Through the self-check process, it can be determined that the photo sensor can receive sufficient light, thereby determining that the current smoke alarm can perform normal smoke alarm work and sound an alarm when it cannot receive sufficient light. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the implementation scheme of the utility model or the technical scheme in the prior art, the drawings required for use in the implementation scheme or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation schemes of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 This is a schematic diagram of the structure of the prior art of the utility model:

[0018] Figure 2 It is a structural schematic diagram of the utility model;

[0019] Figure 3 This is the first cross-sectional view of the utility model;

[0020] Figure 4 This is the second cross-sectional view of the utility model;

[0021] Figure 5 It is a structural schematic diagram of the self-checking process of the utility model;

[0022] Figure 6 It is a structural schematic diagram of the monitoring process of the utility model;

[0023] Figure 7 This is a principle flow chart of the monitoring process of the utility model;

[0024] Figure 8 It is a principle block diagram of the circuit composition of the utility model;

[0025] Fig. 9 This is a principle flow chart of the self-checking process of the utility model;

[0026] Fig.10 It is a structural schematic diagram of the state adjustment of the light shielding body of the utility model.

[0027] In the figure, 1, monitoring room; 2, light source generating device; 3, photosensor; 4, light shielding body; 5, controller; 6, housing; 7, through hole; 8, second photosensitive element; 9, alarm device; 10, power supply; 11, electromagnet; 12, guide rod; 13, spring; 14, base; 15, first photosensitive element; 16, telescopic rod; 17, micro motor; 18, pump body; 19, liquid storage box. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0029] refer to Figure 1, which is a schematic diagram of the principle structure of the prior art of the utility model smoke alarm, which includes a monitoring room 1 defined by a shell 6 (in order to reduce the reflection of light, the conventional inner wall of the shell is set to black), and a through hole 7 is provided near the top of the periphery. When a fire occurs, the external smoke can enter the interior of the monitoring room 1 through the through hole 7. There is a base 14 inside the monitoring room 1 (the base 14 can be a circuit board or a plate-shaped body stabilized inside the monitoring room 1), and the base 14 has a light source generating device 2, a photosensitive element 3, a controller 5, an alarm device 9 and a power supply 10, wherein there are two photosensitive elements 3, and for the convenience of description, the two photosensitive elements 3 are named as a first photosensitive element 15 and a second photosensitive element 8, and the first photosensitive element 15 and the photosensitive element 8 are provided. The light source generating device 2 is arranged on both sides of the light shielding body 4, and under the obstruction of the light shielding body 4, the light of the light source generating device 2 cannot be directly received by the first photosensitive element 15, and the second photosensitive element 8 and the light source generating device 2 are arranged on the same side of the light shielding body 4, so that the second photosensitive element 8 is not affected by the light shielding body 4 and can directly receive the light emitted by the light source generating device 2. The controller 5 determines whether an alarm needs to be issued by judging whether the light intensity received by the first photosensitive element 15 reaches a threshold value. Under normal circumstances, the light of the light source generating device 2 cannot directly reach the first photosensitive element 15, so the first photosensitive element 15 cannot receive the light, and the controller 5 will not issue an alarm signal. When there is smoke inside the monitoring room 1, the light emitted by the light source generating device 2 The light can be reflected and then bypass the obstruction of the light shielding body 4 and be received by the first photosensitive element 15. When the light intensity received by the first photosensitive element 15 exceeds the first threshold value, the controller 5 controls the alarm device 9 to work and sound an alarm. In particular, after the smoke alarm has been used for a long time, dust in the air will adhere to the light source generating device 2 and the first photosensitive element 15, or the light intensity emitted by the light source generating device 2 will be reduced due to insufficient power. When there is smoke inside the smoke alarm, the light intensity received by the first photosensitive element 15 cannot reach the set first threshold value, thereby making it impossible to sound an alarm. This problem can be overcome by changing the first threshold value. Specifically, the second photosensitive element 8 can directly receive the light source. The controller 5 adjusts the first threshold value through the light intensity received by the second photosensitive element 8, that is, when the light intensity received by the second photosensitive element 8 becomes weaker, the first threshold value is lowered, and when the light intensity received by the second photosensitive element 8 increases, the second threshold value is increased, thereby avoiding the problem that the light intensity of the light source generating device 2 becomes weaker due to dust adhering to the surface of the photoreceptor 3 or dust adhering to the surface of the light source generating device 2 or insufficient power, resulting in the first photosensitive element 15 being unable to receive the light intensity exceeding the first threshold value and alarm. The above is a description of the prior art of the utility model. The deficiency of the prior art is that it is impossible to ensure that the dust coverage degree of the first photosensitive element 15 and the second photosensitive element 8 is the same.Therefore, the threshold adjustment error is large when two photosensitive elements 3 are used. For example, if the surface of the first photosensitive element 15 is covered with more dust, while the surface of the second photosensitive element 8 is covered with less dust (this is mostly caused by insects entering the interior of the smoke sensor, resulting in uneven stains on the surfaces of the two photosensitive elements, or spiders entering the monitoring room and weaving webs on one side), the threshold adjustment will be inaccurate. Secondly, if the first photosensitive element 15 is damaged and the second photosensitive element 8 is intact, the problem of the smoke alarm cannot be discovered in time. Based on the above situation, it is necessary to design a smoke alarm that adjusts the threshold according to the received light intensity to solve the above problem.

[0030] refer to Figure 2-Figure 6 This is a schematic diagram of the structure of the utility model. First, refer to Figure 2 The exterior of the smoke alarm is a housing 6 having a through hole 7. Figure 3-Figure 6 The monitoring room 1 formed inside the shell 6 has a light source generating device 2, a light sensor 3, a light shielding body 4, a controller 5, an alarm device 9, a controller 5 and a power supply 10. The difference in structure between the smoke alarm and the prior art is that only one light sensor 3 is used to adjust the threshold value, and the state of the light shielding body 4 can be switched between a first state that prevents the light sensor 3 from directly receiving the light generated by the light source generating device 2 and a second state that does not affect the light sensor 3 from directly receiving the light generated by the light source generating device 2. The difference in working process between the smoke alarm and the prior art is that the smoke alarm of the utility model has a self-checking process and a monitoring process. Specifically, as Figure 3 As shown, at this time, the smoke alarm is in the monitoring process, and the controller 5 controls the light shielding body 4 to be in the first state. At this time, the light generated by the light source generating device 2 is blocked by the light shielding body 4 and cannot be directly received by the light sensor 3. When the external smoke enters the monitoring chamber 1 of the smoke alarm, as shown in FIG. Figure 6 and Figure 7 As shown, the light generated by the light source generating device 2 is reflected by the large particle molecules in the smoke, thereby bypassing the blocking of the light shielding body 4 and being received by the light sensor 3. When the intensity of the received light reaches a first threshold, the controller 5 controls the alarm device 9 to give an alarm prompt, such as Figure 5 As shown, at this time, the smoke alarm is in the self-check process, and the controller 5 controls the light shielding body 4 to be in the second state. At this time, the light generated by the light source generating device 2 will not be affected by the light shielding body 4, and can be directly irradiated on the photo sensor 3. The controller 5 adjusts the first threshold value of the light intensity that can trigger an alarm in the subsequent monitoring process according to the light intensity received by the photo sensor 3 at this time, thereby achieving the adjustment of the first threshold value of the light intensity that can trigger an alarm by only using one photo sensor 3. Since the self-check process only uses one photo sensor 3, it is also possible to promptly discover the problem that the smoke alarm cannot work normally due to damage to the photo sensor 3.

[0031] It should be further explained that the adjustment of the first state and the second state of the light shielding body 4 can be implemented in a variety of ways. In order to enable those skilled in the art to implement this solution, a method for implementing the switching of the light shielding body 4 between the first state and the second state is described in detail. Figure 3-Figure 5 First, the light source generating device 2 and the photosensitive sensor 3 are installed on the same base 14. The light shielding body 4 that can be magnetically adsorbed is stabilized above the base 14 and is located between the light source generating device 2 and the photosensitive sensor 3 through the guide rod 12 and the spring 13. The spring 13 is sleeved on the outside of the guide rod 12 between the light shielding body 4 and the base 14. The light shielding body 4 can slide up and down along the guide rod 12 and is penetrated by the guide rod 12. An electromagnet 11 is installed on the base 14 and below the light shielding body 4. When the controller 5 energizes the electromagnet 11, the electromagnet 11 has magnetism, and the electromagnet 11 adsorbs the light shielding body 4, driving the light shielding body 4 to move downward. At this time, the light shielding body 4 is in the second state, and the light The light generated by the source generating device 2 can directly illuminate the photosensitive element 3. When the controller 5 does not energize the electromagnet 11, the electromagnet 11 does not have magnetism. The light shielding body 4 is reset under the support of the spring 13. At this time, the light shielding body 4 is in the first state. The light generated by the light source generating device 2 cannot directly illuminate the photosensitive element 3. Therefore, the movement of the light shielding body 4 is controlled by the controller 5, so that the light shielding body 4 switches between the first state and the second state, thereby corresponding to the switching of the smoke alarm between the self-test process and the monitoring process. The switching of the light shielding body 4 between the first state and the second state is not limited to a linear up and down movement. It can be seen from the above description that it is easy for a person skilled in the art to think of it with reference to Fig.10 a, the light shielding body 4 can also be driven by a telescopic rod 16 to move horizontally on the midline of the connecting line between the light source generating device 2 and the light sensor 3, or refer to Fig.10 b. By setting a micro motor 17 to drive the light shielding body 4 to rotate, both methods can realize the switching of the light shielding body 4 between blocking the light directly emitted to the photoreceptor 3 and not blocking the light directly emitted to the photoreceptor 3. No matter which method is adopted, as long as the light shielding body 4 can be switched between the two states of blocking the light emitted by the light source generating device 2 from directly reaching the photoreceptor 3 and not blocking the light emitted by the light source generating device 2 from directly reaching the photoreceptor 3, it will be sufficient. At the same time, the switching between the first state and the second state of the light shielding body 4 is not limited to the movement of the light shielding body 4. That is, it is easy for technical personnel in this field to think that by fixing the light shielding body 4 and changing the position of the light source generating device 2 and / or the photoreceptor 3, the switching between the first state and the second state can also be realized. Furthermore, the switching between the first state and the second state is not limited to the position adjustment of the light shielding body 4, the light source generating device 2 and / or the photoreceptor 3, refer to Fig.10c. It can also be achieved by changing the transparent state of the light shielding body 4. For example, the light shielding body 4 is set as a transparent shell cover. When it is necessary to block the light of the light source generating device 2 from directly irradiating the photoreceptor 3, the controller 5 controls the pump body 18 to transport the black ink inside the liquid storage box 19 to the inside of the light shielding body 4 formed by the transparent shell cover to block the light. At this time, the light shielding body 4 is in the first state. When it is not necessary to block the light of the light source generating device 2 from directly irradiating the photoreceptor 3, the controller 5 controls the pump body 18 to discharge the opaque pigment inside the transparent shell cover. At this time, the light shielding body 4 is in the second state.

[0032] For further reference, Figure 8 The controller 5 is externally connected to the photosensitive element 3, the alarm device 9 and the electromagnet 11 (if the movement of the light shielding body is controlled by a non-electromagnetic method, the electromagnet here corresponds to other driving parts, such as the telescopic rod 16, the micro motor 17, etc. mentioned above). The controller 5 controls the smoke alarm to perform the self-check process and the monitoring process cycle, which can be set by a clock signal, that is, the controller 5 has a clock module inside. Of course, the clock module can also be an independent clock chip independent of the controller 5. The clock module is used to provide a clock signal to the controller 5. When the monitoring process time is reached, the controller 5 controls the smoke alarm to perform a self-check process. Since the self-check process is mainly to avoid the influence of dust, which causes it to not work normally, and the period required for the influence of dust is relatively long, the time period of the self-check process can be set to three days, half a month, one month or other time. Since the self-check process only needs the photosensitive element 3 to collect the light intensity directly emitted by the light source generating device 2 to complete, the required time is very short (when the electromagnet 11 method is used above, it can be completed by moving the light shielding body 4 up and down once), so it will not affect the normal monitoring process.

[0033] It should be further explained that the reference Fig. 9 During the self-test process, the smoke alarm is also used to determine whether the light intensity of the light emitted by the light source generating device 2 directly irradiating the photo sensor 3 is lower than the second threshold value, that is, when the light intensity received by the photo sensor 3 during the self-test process is lower than the second threshold value, the current light intensity is too low or no light is received by the photo sensor 3, which may cause enough smoke to enter the smoke alarm. When the light reflected by the smoke reaches the photo sensor 3, it cannot trigger the alarm. The possible reasons are that the light source generating device 2 and / or the photo sensor 3 are damaged, or the battery is extremely low, and the light emitted by the light source generating device 2 itself is lower than the first threshold value. At this time, the controller 5 determines that the self-test is abnormal and controls the alarm device 9 to issue an alarm prompt. When the controller 5 determines that the light intensity received by the photo sensor 3 is greater than the second threshold value, it also adjusts the first threshold value that can trigger the alarm device 9 to issue an alarm during the subsequent monitoring process according to the intensity of the received light.

[0034] It should be further explained that the alarm device 9 can adopt a speaker and / or an indicator light, and emit a prompt sound and / or a prompt light when receiving the alarm signal from the controller 5.

[0035] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A smoke alarm capable of adjusting a threshold value according to the intensity of received light, comprising a light source generating device (2) for generating light, a light sensor (3) for receiving light emitted by the light source generating device (2), a light shielding body (4) between the light source generating device (2) and the light sensor (3), and a controller (5) for sending an alarm signal when the intensity of light received by the light sensor (3) exceeds a first threshold value during smoke monitoring, characterized in that: The working process of the smoke alarm is divided into a self-checking process and a monitoring process. During the monitoring process, the light shielding body (4) is in a first state that prevents the light sensor (3) from directly receiving the light generated by the light source generating device (2). During the self-checking process, the light shielding body (4) is in a second state that does not affect the light sensor (3) from directly receiving the light generated by the light source generating device (2). The first state and the second state of the light shielding body (4) are controlled by a controller (5). The controller (5) adjusts a first threshold value capable of triggering an alarm during the monitoring process according to the light intensity received by the light sensor (3) during the self-checking process.

2. A smoke alarm that adjusts the threshold according to the received light intensity according to claim 1, characterized in that: The controller (5) realizes the switching between the self-checking process and the monitoring process by adjusting the relative positions of the light shielding body (4), the light source generating device (2) and the light sensor (3).

3. A smoke alarm that adjusts the threshold according to the received light intensity according to claim 1, characterized in that: The light shielding body (4) can be magnetically adsorbed and mounted on a base (14); a guide rod (12) penetrating the light shielding body (4) is arranged on the base (14); a spring (13) is sleeved on the outside of the guide rod (12) between the light shielding body (4) and the base (14); an electromagnet (11) is arranged on the base (14) and below the light shielding body (4); when the controller (5) controls the electromagnet (11) to be energized, the light shielding body (4) is adsorbed onto the electromagnet (11), and the light shielding body (4) is in a second state; when the controller (5) controls the electromagnet (11) to be de-energized, the light shielding body (4) is detached from the electromagnet (11) under the support of the spring (13), and the light shielding body (4) is in a first state.

4. The smoke alarm that adjusts the threshold value according to the received light intensity according to claim 1, characterized in that: The controller (5) controls the smoke alarm to switch between the self-checking process and the monitoring process according to the clock signal of the clock module.

5. The smoke alarm that adjusts the threshold value according to the received light intensity according to claim 1, characterized in that: When the smoke alarm is in a self-checking process, if the light intensity received by the light sensor (3) is less than a second threshold value, the controller (5) sends out an alarm signal; if the light intensity received by the light sensor (3) is greater than the second threshold value, the controller (5) adjusts the size of the first threshold value according to the received light intensity.

6. The smoke alarm that adjusts the threshold value according to the received light intensity according to claim 1, characterized in that: It also comprises an alarm device (9). When the alarm device (9) receives an alarm signal from the controller (5), the alarm device (9) issues an alarm. The alarm device (9) is a speaker and / or an indicator light.

7. The smoke alarm that adjusts the threshold value according to the received light intensity according to claim 1, characterized in that: The light shielding body (4) switches between the first state and the second state by changing its own transparency.

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