A system for monitoring abnormal changes in air in a relatively limited space based on optical interference

Abstract

A system for monitoring anomalous changes in the air within a confined space based on optical interference is provided. The optical path system includes a light source device 3 with a light source built in, a reflecting prism 10, and a triangular prism 11. The sealed air chamber includes an air chamber passage that penetrates horizontally, and both ends of the air chamber passage are vertical planes. The reflecting prism and the triangular prism are respectively arranged on the opening side of both ends of the air chamber passage. After passing through a narrow slit, the light beam emitted from the light source is reflected and refracted by the reflecting prism and the triangular prism to form interference fringes. The photoresistor converts the shift change of the interference fringes into an electrical signal. The light from the light source passes through the air chamber passage in parallel along the reflected light path formed by the reflection of the reflecting prism and the reflection of the triangular prism, or the refracted light path formed by the refraction of the reflecting prism and the reflection of the triangular prism.

Description

[Technical field]

[0001] The present invention relates to the technical field of gas monitoring devices, and more particularly to a system for monitoring abnormal changes in air within a limited space based on optical interference. [Background technology]

[0002] In recent years, it has been found that in relatively limited spaces (such as relatively closed spaces such as restaurants, home kitchens, chemical laboratories, underground common sewer pipes, special industrial environments, and chemical industry workshops), serious disasters that cannot be evaluated occasionally occur due to abnormal or sudden changes in the air. Therefore, it is necessary to monitor abnormal or sudden changes in the air in a specific limited space and deal with them in a timely manner. Currently, the methods commonly used in the field of gas monitoring are as follows: catalytic element method, electrochemical method, semiconductor method, infrared spectrum method, and laser spectrum method. All of these technical means monitor a single gas, and cannot quickly and effectively monitor and control abnormal or sudden changes in the air caused by uncertain types of gas concentration changes, and there are limitations in detection. There is also a method of detecting air using optical interference method. For example, optical interference methane meters can detect the concentration of gases such as methane and carbon dioxide, but when using them, the user must manually extract a certain amount of the gas to be measured, inject it into the sampling chamber, and then visually observe the amount of movement of the optical interference fringes inside the device. This means that the detection results are easily affected by human operation, and since the gas that is monitored is only the extracted gas and real-time air cannot be monitored, there is a certain delay in this monitoring method. Summary of the Invention

[0003] Therefore, based on the above background, the present invention provides a system for monitoring abnormal changes in air in a relatively limited space based on optical interference. The system can monitor abnormal or sudden changes in air by monitoring the shift of interference fringes, and targets abnormal or sudden changes in air caused by uncertain types of gas concentrations. In addition, the system does not need to extract gas and inject it into the air chamber, and can monitor the air in real time. The system is easy to operate, has high sensitivity and fast response.

[0004] The technical means provided in this invention are as follows: The optical path system includes a light source device 3, a reflecting prism 10, and a triangular prism 11. The light source device 3 includes a lamp housing with a light source therein, and the lamp housing includes a lamp housing cover having a narrow slit 6. The sealed air chamber 12 has a penetrating air chamber passage in the horizontal direction, and the openings at both ends of the air chamber passage are vertical planes. The openings at both ends of the air chamber passage are sealed by light-transmitting plates 16. The reflecting prism 10 and the triangular prism 11 are respectively arranged on the opening sides at both ends of the air chamber passage.

[0005] Here, the light beam emitted from the light source passes through a narrow slit 6, and is then reflected and refracted by a reflecting prism to form an A1 light beam and a B light beam, respectively. The A1 and B light beams are reflected by the triangular prism to form A2 and B1 light beams, respectively. The A2 and B1 light beams are refracted and reflected by the reflecting prism to merge and form interference fringes with alternating light and dark. The A1 light beam, the B light beam, the A2 light beam, and the B1 light beam are all parallel to the air chamber passage, among which the A1 light beam and the A2 light beam pass through the air chamber passage in parallel, or the B light beam and the B1 light beam pass through the air chamber passage in parallel.

[0006] Furthermore, the triangular prism 11 is a right-angled isosceles triangular prism. Furthermore, a focusing lens 8 is provided between the narrow slit 6 and the reflecting prism 10 , and the light beam emitted from the light source passes through the narrow slit 6 and is irradiated onto the reflecting prism 10 via the focusing lens 8 . Furthermore, the reflecting prism 10 is installed at an angle with respect to the opening end face of the air chamber passage, and the light beam emitted from the light source forms a parallel refracted light beam and a reflected light beam through the reflecting prism, and the refracted light beam or the reflected light beam is parallel to the air chamber passage. Furthermore, the air chamber passage communicates with a copper capillary tube 15 . Furthermore, the copper capillary tube 15 has an inner diameter of 0.5 mm. Furthermore, the side surface on which the hypotenuses of the two triangular faces of the triangular prism 11 coexist faces one end of the air chamber passage. Furthermore, a first substrate 17 is provided below the triangular prism 11, and an adjustment component is provided on the first substrate 17, so that the left and right tilt angles of the first substrate 17 can be adjusted via the adjustment component. Furthermore, the reflecting prism 10 and the triangular prism 11 are made of the same material. Furthermore, the reflecting prism 10 and the triangular prism 11 are made of either polycarbonate or polymethylmethacrylate or cycloolefin polymer.

[0007] By adopting the above technical means, the beneficial effects of the present invention are as follows: The structure of this device is based on the principle of optical interference, utilizing the change in gas density caused by abnormal or sudden changes in the air, two light beams refracted and reflected by a reflecting prism pass through the relatively stable pure air in a sealed air chamber and the air in the limited space to be monitored, respectively, and then the light beams are combined to form interference fringes that cause an overall shift change, and the shift change in the interference fringes is converted into an electrical signal through a photoresistor, thereby realizing the monitoring of abnormal or sudden changes in the air in the limited space to be monitored. The system can monitor abnormal or sudden changes in the air caused by the concentration of uncertain types of gas, and is easy to operate and highly sensitive. In addition, the present invention only uses a single sealed air chamber containing relatively stable pure air, which does not require the installation of a sampling chamber, and eliminates the need to manually extract and inject the target gas into the sampling chamber, further simplifying the operation. In addition, the real-time air monitoring improves the immediacy of the monitoring results. [Brief description of the drawings]

[0008] In order to more clearly describe the present invention or the technical means in the prior art, the following description will be made with reference to the drawings in a clear and understandable manner. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can further obtain other drawings according to these drawings without creative ingenuity. [Figure 1] 1 is a schematic diagram of the present invention. [Diagram 2] 2 is a schematic diagram of the present invention. [Diagram 3] 3 is a schematic diagram of the present invention. [Figure 4] 4 is a schematic diagram of the present invention. [Diagram 5] 3 is a diagram showing the principle of monitoring changes in gas concentration in an embodiment of the present invention; [Figure 6] 1 is a schematic diagram of the reflecting prism of this invention. [Figure 7] 2 is a schematic diagram of the reflecting prism of the present invention. [Figure 8] 5 is a schematic diagram of the present invention. [Figure 9] 6 is a schematic diagram of the present invention. [Figure 10] 7 is a schematic diagram of the present invention. [Figure 11] 8 is a schematic diagram of the present invention. [Figure 12] 9 is a schematic diagram of the present invention. [Figure 13] 10 is a schematic diagram of the present invention. [Figure 14] FIG. 4 is a diagram showing the principle of monitoring changes in gas concentration in another embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The technical means in the embodiments of the present invention will be described below clearly and completely with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative ingenuity belong to the protection scope of the present invention. The embodiments of the present invention are described in detail below. The examples of the embodiments are shown in the drawings, and the same or similar numbers indicate the same or similar elements or elements having the same or similar functions. In the description of the embodiments of the present invention, the orientations or positional relationships of the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "longitudinal", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for facilitating the description of the present invention and simplifying the description, and do not imply that the device or part has a specific orientation or needs to be arranged or operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the invention, a "first feature" or a "second feature" may include one or more of the features. Additionally, the terms "first" and "second" are used for descriptive purposes only and do not imply any relative importance or quantity of the indicated technical features. Thus, a "first" or "second" feature may include one or more of the features, whether stated or implied.

[0010] The present invention will be explained in more detail below with reference to the drawings. Example 1: As shown in FIG. 1 to FIG. 14, a system for monitoring abnormal changes in air in a relatively limited space based on optical interference includes an optical path system, a sealed air chamber 12, and a photoresistor 9. It should be noted here that in this and subsequent embodiments, the left and right orientations are the directions indicated by the arrows.

[0011] The optical path system includes a light source device 3, a reflecting prism 10, and a triangular prism 11. The light source device 3 is composed of a lamp housing tube with a light source built in, and the lamp housing tube includes a lamp housing tube cover with a narrow slit 6. The width of the slit is 0.5 mm. Specifically, the light source is an LED bulb or light tube, and is an LED bulb or LED light tube that emits a single white light. In this embodiment, the lamp housing tube cover is attached to the lamp housing tube by screwing. For example, as shown in FIG. 1, the lamp housing tube is a tube with one end sealed, a first thread (female thread or male thread) is provided on the wall of the open end of the tube, and a second thread corresponding to the first thread is provided inside the cover. The realization method is not limited to the above, and the light cover may be attached to the lamp housing tube by a fitting method. As another embodiment, the lamp housing tube is fitted into a first support plate 3 in the vertical direction and bonded to the first support plate 3 using an adhesive or the like, so that it can be installed in a form that raises the luminous flux of the light source.

[0012] The narrow slit 6 is strip-shaped and extends in the longitudinal direction. The light source device 3 includes a lamp housing cylinder in which a light source is housed, and the lamp housing cylinder includes a lamp housing cylinder cover having a narrow slit 6 . The sealed air chamber 12 has an air chamber passage penetrating horizontally, and the openings at both ends of the air chamber are vertical flat surfaces. The openings at both ends of the air chamber passage are sealed by light-transmitting plates 16, which can be made of organic glass with high light transmittance, for example, polycarbonate (PC) glass or quartz glass with a light transmittance of 90% or more. The light-transmitting plates 16 are glass plates perpendicular to the vertical direction, bonded to both ends of the air chamber passage with optical resin, and adhered to both ends of the sealed air chamber 12. The light-transmitting plates adhered to the end faces of the sealed air chamber 12 are held perpendicular to the vertical direction. In this embodiment, the sealed air chamber 12 is made of polycarbonate (PC) and carbon fiber, which have stable structural performance, and its surface is black and has low light transmittance.

[0013] The reflecting prism 10 and the triangular prism 11 are located on the opening side at both ends of the air chamber passage. After passing through a narrow slit 6, the light beam emitted from the light source is reflected and refracted by the reflecting prism 10 and the triangular prism 11 to form interference fringes. The photoresistor 9 converts an optical signal into an electrical signal. Specifically, the photoresistor 9 converts the shift change of the interference fringes into an electrical signal. The light from the light source passes through the air chamber passage in parallel along a reflected optical path formed by reflection of the reflecting prism 10 and reflection of the triangular prism, or along a refracted optical path formed by refraction of the reflecting prism 10 and reflection of the triangular prism.

[0014] Specifically, the light beam emitted from the light source passes through a narrow slit 6, and then is reflected and refracted by the reflecting prism to form the A1 light beam and the B light beam, respectively. The A1 light beam and the B light beam are reflected by the triangular prism to form the A2 light beam and the B1 light beam. The A2 light beam and the B1 light beam are refraction and reflection by the reflecting prism, respectively, and merge to form light and dark interference fringes. The A1 light beam, the B light beam, the A2 light beam and the B1 light beam are all parallel to the air chamber passage, in which the A1 light beam and the A2 light beam pass through the air chamber passage in parallel, or the B light beam and the B1 light beam pass through the air chamber passage in parallel. This embodiment is shown in FIG. 5, in which the B light beam and the B1 light beam pass through the air chamber passage in parallel.

[0015] A focusing lens 8 is installed between the narrow slit 6 and the reflecting prism 10, and the light from the light source passes through the narrow slit 6, then passes through the focusing lens 8 and is emitted to the reflecting prism 10. In another embodiment, the focusing lens 8 is fitted into the second support plate 7, so that it can be raised adaptively according to the height of the light source. For example, the focusing lens 8 can be bonded to the second support plate 7 using an adhesive. In this embodiment, as specifically shown in FIG. 5, the optical path refracted by the reflecting prism 10 passes in parallel through the air chamber passage, and the optical path formed by refraction by the reflecting prism 10 and reflection by the triangular prism passes in parallel through the air in the limited space to be monitored.

[0016] The realization principle of this invention is as follows: the light beam from the light source passes through a narrow slit, is focused by a focusing lens, and is then emitted to a reflecting prism, which forms A1 and B light beams through reflection and refraction. The A1 and B light beams are reflected by a triangular prism, which forms A2 and B1 light beams. The A2 and B1 light beams are reflected and refracted by the reflecting prism, which then merge to form an interference fringe with alternating light and dark. For better explanation, the A1 and A2 light beams are collectively referred to as the reflected light beam (reflected light path), and the B and B1 light beams are collectively referred to as the refracted light beam (refracted light path).

[0017] A change in the concentration of a particular gas or gases in the air causes a change in the density of the air. When a light ray passes through materials of different densities, the travel distance is different. This phenomenon is called the "difference in optical paths." If the reflected light beam consisting of A1 and A2 passes through a different path than the refracted light beam consisting of B and B1, the interference fringes formed after the merging will move up and down as a whole, and a shift change will appear. In this embodiment, the refracted light path passes horizontally through the air in the limited space to be monitored, and the reflected light path passes parallel to the air chamber of relatively stable pure air. If an abnormal or sudden change appears in the air in the limited space to be monitored (the air outside the sealed air chamber), a shift change will occur in the interference fringes formed after the refracted light path and the reflected light path merge. This shift change in the interference fringes, which alternate between light and dark, will cause a change in the resistance value of the photoresistor. Therefore, by converting the shift change in the interference fringes into an electric signal via the photoresistor, monitoring of abnormal or sudden changes in the air is realized.

[0018] In a specific implementation, by adaptively setting the relative positions and dimensions of the light source, triangular prism, reflecting prism, and sealed air chamber, it becomes possible for the light path refracted by the reflecting prism 10 to pass parallel to the air chamber passage, and at the same time for the light path formed by the refraction of the reflecting prism 10 and the reflection of the triangular prism to pass parallel to the air in the limited space of the monitoring target. Also, it is required that no parts that affect the passage of the light beam are placed between the refracting prism and the triangular prism. The triangular prism 11 is an equilateral triangular prism.

[0019] The air chamber passage is connected to a copper capillary tube 15, which is for removing the influence of changes in environmental temperature and fluctuations in environmental atmospheric pressure, and for preventing the purity of the pure air in the air chamber from being influenced by the environment. The inner diameter of the copper capillary tube 15 is 0.5 mm. Specifically, the copper capillary tube in this embodiment is wound, and one end of the copper capillary tube is connected to the atmosphere, so that the air pressure of the pure air in the air chamber is the same as the air pressure of the gas to be monitored outside. On the other hand, by winding the tube, the gas in the air chamber is not exchanged with the atmosphere, and a relatively sealed air chamber space is formed. The installation of the copper capillary tube makes it possible to maintain equilibrium between the pressure and temperature of the air in the sealed air chamber.

[0020] The reflecting prism 10 and the triangular prism 11 are made of the same material to ensure optical performance and consistency. The reflecting prism 10 and the triangular prism 11 are prisms with a high light transmittance of 90% or more made of either polycarbonate, polymethyl methacrylate, or cycloolefin polymer. In a specific embodiment, the upper and lower surfaces of the triangular prism 11 are triangular surfaces, and the sides of the triangular prism 11 are all vertical surfaces. Furthermore, the side with the hypotenuses of the two triangular surfaces faces one end of the air chamber. Preferably, the upper and lower triangular surfaces of the triangular prism 11 are all matte finished.

[0021] 6 and 7, the reflecting prism includes a vertical reflecting surface 21 and a rear surface 22 that is parallel to and faces the reflecting surface 21. An angle exists between the reflecting surface and the opening end surface of the air chamber passage. Preferably, the backs of the opposing reflecting surfaces of the reflecting prism are silver plated and further coated with a black coating to improve the refraction of the light beam. A first substrate 17 is provided below the triangular prism 11, and an adjustment component is provided on the first substrate 17. The left and right tilt angles of the first substrate 17 can be adjusted by this adjustment component.

[0022] The type of photoresistor used in this embodiment is TV30, and the general principle of converting the shift change of the optical interference into an electrical signal is as follows: When the selected dark stripe moves up and down, it will shade the light-sensitive part of the photoresistor. The resistance value of the photoresistor will change according to the amount of shading. Preferably, the width of the interference stripe is adjusted to 2mm. This can be achieved by adjusting the left and right tilt angles with the adjustment parts installed on the first substrate 17. Specifically, the first substrate 17 is provided with a first convex pillar 18, and the triangular bottom surface of the triangular prism 11 is adhered to the first convex pillar 18 by adhesive. Preferably, the first convex pillar is a threaded rod, and is attached to the first substrate 17 by screwing.

[0023] In addition, a second substrate 19 is provided under the reflecting prism, and the second substrate 19 has a second convex pillar, and the bottom surface of the reflecting prism is adhered to the second convex pillar by adhesive. Preferably, the second convex pillar is a threaded rod and is attached to the second substrate 19 by screwing, which allows the triangular pillar or the reflecting prism to be easily attached and detached. In addition, the second substrate 19 is placed directly on the substrate 26, and the angle between the reflecting surface of the reflecting prism and the opening end surface of the air chamber passage can be adjusted, so that the light beam reflected or refracted by the reflecting prism can be parallel to the air chamber passage or pass through the air chamber passage. Preferably, the sealed air chamber is attached to the substrate. Specifically, it can be attached by adhesive or by bolts, for example, there is a fixing plate extending from the bottom surface of the sealed air chamber, and the fixing plate is attached to the substrate by bolts.

[0024] Also, as shown in FIG. 8 and FIG. 9, a recess 27 is provided at the position of the triangular prism of the substrate, and the first substrate 17 is located above the recess 27. Specifically, the left side of the first substrate 17 is attached to a connecting plate 28 by a bolt, and the other end of the connecting plate 28 is attached to the side wall of the recess of the substrate by a bolt. An adjustment part is provided on the opposite side of the connecting plate of the first substrate, and the structure of the adjustment part is shown in FIG. 8 and FIG. 9. The adjustment part includes a nut 30 and a threaded rod 31 that matches the nut, and the nut is fixed to the bottom surface of the recess, for example, by welding. The threaded rod 31 is tightened into the nut 30, and the upper end of the threaded rod 31 contacts the bottom surface of the first substrate, providing a certain support to the first substrate. Alternatively, as shown in FIG. 10, a nut is fixed to the upper surface of the first substrate, and the bottom end of the first threaded rod 31 passes through the nut and contacts the bottom surface of the recess, providing a certain support to the first substrate. The left and right tilt angle of the first board can be adjusted by rotating the screw rod in the nut. In one implementation method, the connection plate 28 is made of a spring copper plate with a deformation function, and can be adapted to adjust the left and right tilt angle of the first board through deformation.

[0025] More specifically, in actual operation, when the screw rotates once, the height difference of the opposite side of the connecting plate of the first substrate is controlled to within 0.25 mm. At this time, by adjusting the left and right tilt angle of the first substrate, the left and right tilt angle of the triangular prism is also changed, and the width of the dark stripes can be adjusted. Usually, the rotation angle of the screw is 5 to 10 degrees.

[0026] Alternatively, the connecting plate may be realized in other ways. In that case, the connecting plate is made of a material that does not have the ability to deform (e.g. polypropylene plastic), in which case the connecting plate is composed of a bifurcated plate (first and second plates). The first plate is adjacent to the triangular prism, and a rotational connection is possible between the first and second plates. Specifically, a bush is installed on the side of the first plate, and a rotation axis is provided on the second plate, which passes through the bush. In this way, by using the movable first and second plates, the need for adjusting the left and right tilt angle of the first substrate can be met.

[0027] Example 2: A system for monitoring abnormal changes in air in a relatively limited space based on optical interference, based on Fig. 1 to Fig. 8. In this example, the optical path system, the sealed air chamber 12, and the photoresistor 9 of the system are integrated into a housing 1. The housing 1 includes a first case and a second case connected by a hinge, for example, through a general hinge. This is an existing technology and will not be described in detail. Of course, the connection method is not limited to the hinge.

[0028] Specifically, a connecting tube 13 is fixed to the sealed air chamber, and a connecting flexible tube 14 is attached to one end of the connecting tube. A copper capillary tube 15 is connected to the other end of the connecting flexible tube 14, and the connecting flexible tube is made of an elastically deformable material (e.g., polyethylene), and the inner diameter of the connecting flexible tube is the same as or slightly smaller than the outer diameter of the connecting tube and the copper capillary tube 15. The optical path system, the sealed air chamber 12, and the photoresistor 9 are integrated into a first case, and the copper capillary tube 15 is disposed in a second case. The substrate 26 is fixed inside the first case, for example by means of bolts or adhesive, or it may be molded integrally with the first case. A battery 20 is also installed in the first case. The battery 20 is electrically connected to the light source and the photoresistor and supplies power to the light source and the photoresistor.

[0029] Example 3: This example is based on Example 2 and has an air hole 23 on the opposite side of the second case to the first case. The air hole 23 is a through hole, and a waterproof / moisture-permeable membrane 25 is attached to the side closer to the inside of the first case. Preferably, a protrusion 24 extends through the through hole on the side closer to the inside of the first case, and a waterproof / moisture-permeable membrane 25 is also attached to the opening of the protrusion 24.

[0030] Example 4: This example is different from Example 1 and Example 2, in that the light path formed by the refraction of the reflecting prism 10 and the refraction of the reflecting prism pass through the air chamber passage in parallel, and the refracted light path formed by the refraction of the reflecting prism 10 passes through the air in the limited space to be monitored, thereby realizing the present invention. In this example, two sealed air chambers (see FIG. 14) are installed, and the A1 light beam formed by the refraction of the reflecting prism and the A2 light beam reflected by the triangular prism pass through the air chamber passage of the sealed air chamber in parallel.

[0031] Example 5: Based on Figures 1 to 8, a system for monitoring abnormal changes in air in a relatively limited space based on optical interference is based on Examples 2 to 4. The photoresistor 9 is disposed on the circuit board 2. A microcontroller is installed on the circuit board 2, and the microcontroller is electrically connected to the photoresistor. The signal output terminal of the photoresistor is connected to the signal input terminal of the microcontroller, and the power supply supplies power to the microcontroller.

[0032] More specifically, an alarm module is provided on the circuit board 2, the alarm module being a buzzer or a flashing light, and the alarm module is electrically connected to a microcontroller. The signal output terminal of the microcontroller is connected to the signal output terminal of the alarm module, and the power supply supplies power to the alarm module. The microcontroller receives an electrical signal based on the optical interference shift change from the photoresistor, and when the optical interference shift change monitored by the photoresistor exceeds a set value, it outputs a signal to the alarm module to issue an alarm.

[0033] In the specific operation of the present invention, the sealed air chamber is filled with pure air (specifically, the pure air contained in the sealed air chamber is standard air filled in the assembly process in a clean room, and the copper capillary tube allows the standard air chamber to be relatively isolated from the environment after it is sealed. The standard air is air under the conditions of atmospheric pressure 101.325 KPa, temperature 25°C, and relative humidity 50%), and a relatively sealed state is realized by using a transparent plate and a copper capillary tube. In the first and second embodiments, the closed housing is placed in the limited space of the measurement target, and the housing is opened and the battery switch is turned on, so that the air in the relatively limited space can be monitored for any abnormal changes.

[0034] In the third and fifth embodiments, the closed housing is placed in the limited space to be measured, and the battery switch is turned on, thereby making it possible to monitor whether there are any abnormal or sudden changes in the air in the limited space.

[0035] Although the present invention and its implementation modes have been described above, such description is not restrictive, and what is shown in the drawings is merely one of the implementation modes of the present invention, and the actual application is not limited thereto. In other words, the structural aspects and embodiments similar to the technical means designed by a person skilled in the art without departing from the creative spirit of the present invention by receiving the suggestions therefrom should all fall within the scope of protection of the present invention.

Claims

1. A system for monitoring abnormal changes in air within a relatively limited space based on optical interference, comprising: The optical path system includes a light source device 3, a reflecting prism 10, and a triangular prism 11, the light source device 3 includes a lamp housing barrel with a light source therein, the lamp housing barrel includes a lamp housing barrel cover having a narrow slit 6, The sealed air chamber 12 has a penetrating air chamber passage in the horizontal direction, and the openings at both ends of the air chamber passage are vertical flat surfaces. The openings at both ends of the air chamber passage are sealed by light-transmitting plates 16. The reflecting prism 10 and the triangular prism 11 are respectively disposed on the opening sides at both ends of the air chamber passage. Specifically, the light beam emitted from the light source passes through a narrow slit 6, and then is reflected and refractionally formed by the reflecting prism into a light beam A1 and a light beam B, respectively. The light beam A1 and the light beam B are reflected by the triangular prism, and then are formed into a light beam A2 and a light beam B1, respectively. The light beam A2 and the light beam B1 are refraction and reflection respectively by the reflecting prism, and merge to form light and dark interference fringes. The light beam A1, the light beam B, the light beam A2 and the light beam B1 are all parallel to the air chamber passage, among which the light beam A1 and the light beam A2 pass through the air chamber passage in parallel, or the light beam B and the light beam B1 pass through the air chamber passage in parallel, The system for monitoring abnormal changes in air within a relatively limited space based on optical interference is characterized in that the photoresistor 9 converts an optical signal into an electrical signal.

2. 2. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as claimed in claim 1, wherein said triangular prism 11 is a right-angled isosceles triangular prism.

3. 2. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as described in claim 1, characterized in that a focusing lens 8 is provided between the narrow slit 6 and the reflecting prism 10, and the light beam emitted from the light source passes through the narrow slit 6 and is irradiated onto the reflecting prism 10 via the focusing lens 8.

4. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as described in claim 3, characterized in that the reflecting prism 10 is installed at an angle to the opening end face of the air chamber passage, the light beam emitted from the light source forms a parallel refracted light beam and a reflected light beam through the reflecting prism, and the refracted light beam or the reflected light beam is parallel to the air chamber passage.

5. 2. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as claimed in claim 1, wherein said air chamber passage is connected to a copper capillary tube (15).

6. 6. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as claimed in claim 5, wherein the copper capillary tube 15 has an inner diameter of 0.5 mm and a length of 800 mm.

7. 2. A system for monitoring abnormal changes in air within a relatively limited space based on optical interference as described in claim 1, characterized in that the side on which the hypotenuses of the two triangular faces of the triangular prism 11 exist simultaneously faces one end of the air chamber passage.

8. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as described in claim 7, characterized in that a first substrate 17 is provided under the triangular prism 11, an adjustment component is provided on the first substrate 17, and the left and right tilt angles of the first substrate 17 can be adjusted through the adjustment component.

9. 2. The system for monitoring air abnormal changes in a relatively limited space based on optical interference as claimed in claim 1, wherein the reflecting prism 10 and the triangular prism 11 are made of the same material.

10. The system for monitoring abnormal changes in air in a relatively limited space based on optical interference as described in claim 7, characterized in that both the reflecting prism 10 and the triangular prism 11 can be manufactured from any of the following materials: polycarbonate, polymethyl methacrylate, cycloolefin polymer, or optical K9 glass.

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