RU2809342C1 - Optical-electronic smoke sensor - Google Patents

Abstract

FIELD: alarms.

SUBSTANCE: optical-electronic smoke sensor contains a socket with fastening, a plastic case with slotted holes in the side of the case, a board, an indicator, an optical module, and a protective grid. The side surface of the housing is made of a cylindrical shape, the protective mesh is made in the shape of a hollow cylinder and is placed inside the casing, the casing is made in the shape of a hollow cylinder and is fixed on the inner surface of the casing using latches, rectangular holes are made on the surface of the casing, additionally installed between the casing and the outer surface of the casing rectangular-shaped catching nets in the amount of 8 pieces; the catching nets are fixed with their side edges in grooves located on the outer side surface of the casing and the inner surface of the housing.

EFFECT: improved efficiency of the sensor by improving the quality of filtration of air penetrating into the housing through slot holes and reducing the labour intensity of operational maintenance.

1 cl, 2 dwg

Description

The proposal relates to the field of fire alarms, namely to optical-electronic smoke detectors of fire alarms with scattered light, which are designed to detect fires accompanied by the appearance of smoke in enclosed spaces with a high dust content.

A known smoke fire detector contains a socket and a sensor, which is a plastic case with slotted holes, inside which there is an optical-electronic system and a board with radio elements (electronic signal processing circuit). (Optical-electronic smoke fire detector IP 212-45, Passport 4371-006-12215496-00 PS). The slotted holes in the sensor housing do not provide effective protection against small insects and dust entering the optical (smoke) chamber.

The practical use of such fire smoke detectors has shown that during operation the frequency of false alarms may increase, and the reason for this is the penetration and deposition of dust particles in the smoke chamber, as well as the entry of insects. To prevent such false alarms from occurring, the smoke chambers of the detectors must be periodically cleaned of dust. Preventative maintenance of the detector involves disassembling it and then cleaning the smoke chamber. This requires both labor costs and carries the risk of broken plastic latches that cannot be repaired, which leads to the need to replace the detector.

There is a known smoke chamber for an optical-electronic fire detector, containing a socket and a sensor, which is a plastic housing with slotted holes, inside which there is an optical-electronic system and a board with radio elements, and on the outside of the smoke chamber on the lid there is a protective mesh with the size of the cells 1x1 mm (RU patent No. 85716, published on August 10, 2009).

The disadvantage of this solution is that when the protective mesh is placed outside directly on the smoke chamber, the working area of the flow section of the protective mesh, limited by the area of the slot holes of the housing, is reduced; as it becomes clogged with dust and other suspended particles (debris), additional resistance to air flow is created, which reduces reliability and prompt response of the detector, especially at the initial stage of fire development with low concentrations of smoke in the air.

An optical-electronic smoke sensor is known (patent RU No. 210807, publ. 05/05/2022), which contains a socket with fastening, a plastic case with slotted holes in the side and bottom of the case, a board, an indicator, an optical module, and a protective mesh. Additionally, a cylindrical container for dust deposition is located inside the housing and is secured to the lower part of the housing with plastic pins installed in grooves made in the lower part of the housing. The protective metal mesh with a cell size of 1x1 mm is made in the form of an inverted truncated cone with an inclination angle of 135 degrees between the generatrix of the cone and the upper part of the case; the protective mesh is installed with its upper base in a groove on the board, and with its lower base in a groove on the dust collection container. The protective mesh is made of metal wire with a diameter of 0.5 mm. The container for dust deposition is made of a plastic cylinder with a base diameter equal to the diameter of the lower base of the protective mesh. The container for dust deposition is 10 mm high.

The disadvantage of this solution is the low efficiency of dust collection inside the sensor housing, due to the circulation of the main amount of dust without its deposition due to its low specific gravity. Another disadvantage is that dust penetrating into the housing through the slotted holes in the cover subsequently gets inside the optical module and causes a false alarm or clogs the protective mesh, reducing the speed of the sensor in the event of a fire with smoke.

The closest to the claimed invention is an optical-electronic fire detector containing a housing, including a socket, a base and a cover with slotted holes, an optical module installed in the housing, including a light source, a light receiver, a labyrinth system, on top of the optical module is shielded with a metal plate, its side the surface is covered with a protective mesh (RU patent No. 48422, 12/15/2004). The socket and base are equipped with a set of projections for their mutual connection. There are contacts installed on the socket and base, the interaction of which ensures electrical contact between the detector and the fire alarm loop. The labyrinth system is formed by the articulation of the plates of the upper and lower parts of the smoke chamber. The housing of the optical module, consisting of a light source, a light receiver and a labyrinth system, is cylindrical. The side surface of the optical module is covered with a protective mesh, and the top part with a metal screen.

The disadvantages of the sensor are that dust penetrating into the housing through the slotted holes of the cover with air subsequently gets inside the optical module and causes a false alarm or clogs the protective mesh, reducing the speed of operation of the sensor in the event of a fire with smoke due to deterioration of air circulation, and Placing a protective grid on the optical module increases the complexity of maintenance and cleaning of the detector.

The technical result of the invention is to increase the efficiency of the sensor by improving the quality of filtration of air penetrating into the housing through slot holes and reducing the labor intensity of operational maintenance.

The technical result is achieved by an optical-electronic smoke sensor containing a socket with fastening, a plastic case with slotted holes in the side of the case, a board, an indicator, an optical module, and a protective grid.

What is new is that the side surface of the housing is made of a cylindrical shape, the protective mesh is made in the shape of a hollow cylinder and is placed inside the casing, the casing is made in the shape of a hollow cylinder and is fixed on the inner surface of the housing with latches, rectangular holes are made on the surface of the casing, additionally between the casing and on the outer surface of the casing there are rectangular-shaped catching nets installed in the amount of 8 pieces, the catching nets with their side edges are fixed in grooves located on the outer side surface of the casing and the inner surface of the housing.

In fig. Figure 1 shows a diagram of an optical-electronic smoke sensor.

In fig. Figure 2 shows a longitudinal section.

The optical-electronic smoke sensor contains a socket 1 (Fig. 1) with a mount 2, a plastic housing 3 (Fig. 1, 2) with slot holes 4 in the side of the housing, a board 5 (Fig. 1), an indicator 6, an optical module 7 (Fig. 1, 2), which includes a light emitter with a light receiver (not shown in the diagram). Inside the housing 3 there is a protective mesh 8 (Fig. 1, 2) made of metal wire 0.2 mm thick with cells 0.5 x 0.5 mm.

The side surface of the body is cylindrical. The protective mesh 8 is made in the form of a hollow cylinder without bases and is placed inside the casing 9 (Fig. 1, 2). The protective mesh 8 is fixed on the sides by the casing 9 and the board 5, on the top by the socket 1, on the bottom by the base of the casing 3. The casing 9 is made in the form of a hollow cylinder and is fixed on the inner surface of the casing using latches (not shown in the figure), on the surface of the casing there are rectangular holes 10 (Fig. 2). The casing 9 is made of plastic.

Between the body 3 and the outer surface of the casing 9 there are catching meshes 11 (Fig. 1, 2) in the form of rectangles in the amount of 8 pieces, equidistant from each other. The mesh size of the catching mesh is 2 times smaller than the protective mesh 8.

On the inner side surface of the housing 3 and the outer side surface of the casing 9, vertical grooves 12 (Fig. 2) and 13 are made for installation and fastening with the side edges of the catching meshes 11. The groove on the outer surface of the casing, which provides fastening of the first side edge of the catching mesh, is located on one axis and is placed parallel to the groove on the inner surface of the housing, which provides fastening of the second side edge of the previous catching mesh in the form of a rectangle.

The collecting meshes are placed in such a way that they create between themselves a passage channel with a width of no more than 30% of the length of the distance between the casing and the body, through which part of the air can flow through the main protective mesh into the optical module bypassing additional collecting meshes, which increases the efficiency of the sensor in the event of clogging of additional collecting grids. The additional catching mesh has a cell size 2 times smaller than the main protective mesh. The additional catching mesh is placed in such a way that it is bent with the outer side inserted into the groove inside the housing at an angle =120 degrees, and the inner side, inserted into the groove from the outside of the casing, at an angle β = 80 degrees. On the inner surface of the base of the housing, inside the space limited by the casing, there are edges 14 at an angle of 45 degrees, which serve as a dust collector for fine dust penetrating through the mesh.

The main components of the smoke sensor (housing, optical module), as in most analogues, are connected to each other with plastic latches, therefore they are not shown in the diagram.

Placing the protective mesh 8 inside the casing simplifies installation and its integrity during inspection. The design of the additional catching mesh 11 allows you to trap circulating dust inside the sensor housing 3. The design of the additional mesh 11 in the form of curved rectangles increases the effective filtration area of air with dust particles, and the cell size is 2 times smaller than the main protective mesh 8 - 0.25x0.25 mm, allows you to catch the finest dust, which provides protection against false alarms when providing high reliability of the optical-electronic smoke sensor in the event of a fire and an increase in the overhaul period of the smoke sensor.

The sensor is assembled as follows.

The protective mesh 8 is fixed on the sides by the casing 9 and the board 5, on the top by the socket 1, on the bottom by the base of the case 3. The casing 9 is fixed with plastic latches inside the base of the case 3, the catching meshes 11 are installed in the grooves 12 and 13, then the case is connected to the socket 1 with using plastic latches. The process of assembling and disassembling the sensor for inspection is simple.

The optical-electronic smoke sensor works as follows.

Optical module 7 with labyrinth channels that prevent light from entering inside, including a light emitter with a light receiver, works similarly to most of those used, so the diagram is shown without detail. Pulse sequences of electrical signals generated by the electronic circuit on board 5 are converted by the light emitter into light pulses. Scattered radiation is received by a light receiver, which is optically inaccessible to direct radiation from a light emitter, the optical axis of which is located at an angle to the optical axis of the light receiver. The resulting scattered reflected radiation is converted by the light receiver into electrical signals, which are processed by elements of the electronic circuit of the board 5 with the subsequent formation of “Standby mode” signals or, in the presence of smoke aerosols, “Fire”.

Dust penetrating through the slot holes 4 in the side surface of the housing 3 circulates inside the housing 3 and the bulk of it is retained by the additional catching mesh 11. Therefore, the service life of the main protective mesh 8 increases in comparison with analogues, which ensures free access of air and smoke inside the optical module 7. In case of significant clogging of the additional catching mesh 11, there is space for the air flow to enter the main mesh 8, bypassing the additional 11 (air flows are shown by arrows).

Thus, the proposed optical-electronic smoke sensor has high protection against false alarms while ensuring the reliability of the optical-electronic smoke sensor in the event of a fire, an increased overhaul period of the smoke sensor, and eliminating clogging of the internal surface of the smoke sensor. The arsenal of technical equipment related to optical-electronic smoke sensors is also expanding.

Claims (1)

An optical-electronic smoke sensor containing a socket with fastening, a plastic case with slotted holes in the side of the case, a board, an indicator, an optical module, a protective mesh, characterized in that the side surface of the case is made of a cylindrical shape, the protective mesh is made in the form of a hollow cylinder and placed inside the casing, the casing is made in the form of a hollow cylinder and fixed on the inner surface of the casing using latches, rectangular holes are made on the surface of the casing, additionally, rectangular-shaped catching meshes are installed between the casing and the outer surface of the casing in the amount of 8 pieces, the catching meshes are secured with the side edges in grooves located on the outer side surface of the casing and the inner surface of the housing.

Images