CN1237339C - Vertical backward scattering type photoelectric smoke detector - Google Patents

Abstract

The present invention relates to a vertical back-scattering photoelectric smoke-sensitive detector which mainly comprises a detection chamber which is composed of a light shielding window (1) and a base (3), a light emitting path which is composed of a light emitter (2) and a light emitting lens (4), and a light receiving path which is composed of a light receiving lens (6) and a light receiver (5). The present invention is characterized in that the angle of the plane determined by the cross of the axis of the light emitted by the light emitter (2) and the central axis of the light received by the light receiving lens (6) and the light receiver (5) and the plane of a circuit board (8) is in the range of 70 degrees to 110 degrees. The unique vertical structure of the detector effectively utilizes the space of the detection chamber, reduces the volume and attenuates the directivity. The detector of the present invention realizes small scattering angle under the condition of the limited space of the detection chamber, responds various types of smog and generates sufficient output signals.

Description

Vertical back scattering type optical detector of fire smoke

Technical field

The present invention relates to optical detector of fire smoke, relate in more detail and be used for the vertical back scattering type optical detector of fire smoke that needs are taken precautions against fire alarm.

Background technology

Optical detector of fire smoke can be divided into forward scattering type, back scattering type and front and back to the two-way dispersion type that combines according to the optical reflection principle.Angle α between the optical axis that the axis of the light that optical transmitting set sends and optical receiver receive: 90 °＜α＜180 °, be called the forward scattering type; Angle α between the axis of the axis of the light that optical transmitting set sends and optical receiver reception light: 0 °＜α＜90 °, be referred to as the back scattering type.

The emission light path of optical transmitting set and the receiving light path intersection of optical receiver are called detecting area.The volume size of detector depends on the full-size of detecting area to a great extent.This influence is very big in back scattering type optical detector of fire smoke, and it is more little to work as scattering angle, the longitudinal space of detecting chamber just requires big more, as shown in Figure 3, wherein the scattering angle of Fig. 3 (b) is with respect to Fig. 3 (a) and Yan Yaoxiao, thereby the size of " D " direction of detecting area is bigger, and required detecting chamber longitudinal space is just bigger.

Relevant back scattering type optical detector of fire smoke all belongs to horizontal type structure from structure in the prior art.The plane that central axis became (A) that is characterized in the central axis of optical transmitting set light path and optical receiver light path is generally 0 ° ± 20 ° with the angle that the plane (B) at wiring board place is constituted.The structure described in the U.S. Pat 4397557 for example, the volume of the back scattering type optical detector of fire smoke of this structure is very big.The volume of desiring to reduce detector is with regard to needs increase scattering angle, and for example the detector of describing among the European patent EP 0880118ZAZ just belongs to this situation.Concerning back scattering type optical detector of fire smoke, scattering angle is more little, and big more to the response output of smog, especially the response characteristic to black smoke is good.Sensitivity to dissimilar smog is good more, for improving the response performance of photo-detector, reduces scattering angle, just must increase its volume; For reduced volume to increase scattering angle, just must weaken the response performance of detector.The shortcoming that horizontal back scattering type optical detector of fire smoke also exists is that directivity is poor.The position at optical transmitting set and optical receiver place can stop entering of smog, and distance is very near between the two, make the space between them become narrow and small, entering of same obstruction smog, and other direction upper signal channel is unimpeded, advance cigarette and be easy to, this makes detector inconsistent to the sensitivity of smog in different directions, causes this optical detector of fire smoke directivity poor.

The object of the present invention is to provide a kind of vertical back scattering type optical detector of fire smoke, can utilize the space of detecting chamber effectively fully, make less detecting chamber can hold the detecting area of longer dimension, thereby improve detection performance of the present invention.

Summary of the invention

The objective of the invention is to be achieved through the following technical solutions.

In vertical back scattering type optical detector of fire smoke of the present invention, the angle that the plane that central axis became of the central axis of the emission light path of optical transmitting set and the receiving light path of optical receiver (A ') and plane, wiring board place (B ') are become is 90 ° ± 20 ° as shown in the figure.This structural design of the present invention has made full use of the space in the detecting chamber, thereby less detecting chamber can hold the detecting area of longer dimension.The longitudinal profile of detecting chamber of the present invention is rectangular, and the length direction of detecting area can improve the space availability ratio of rectangular section like this near the diagonal of this rectangular section.The longest dimension of detecting area longitudinal profile has made full use of the space in the detecting chamber like this on the diagonal line of detecting chamber longitudinal profile.Under the less situation of scattering angle, the size in labyrinth is also less.That is to say that under the certain situation in detecting chamber space, that scattering angle can be designed is littler, to improve the influence output of detector to smog.Scattering angle minimum of the present invention can be accomplished 40 °, and promptly the back scattering angular range can be accomplished 40 °～90 °, can select the angle that needs as required.

It is good directionality that the vertical back scattering type of the present invention optical detector of fire smoke is compared the superiority that is had with existing horizontal back scattering type optical detector of fire smoke.Flue has only optical transmitting set that cigarette is had slightly to stop; Light receiving part does not hinder smog to enter detecting chamber below flue, does not have the narrow gap between optical transmitting set and the optical receiver simultaneously yet, can not influence entering of smog naturally, makes on the detector all directions smog sensitivity unanimity.In addition, in vertical structure, optical receiver is very near apart from wiring board, so can adopt the quantity that has reduced the repair welding device in the plane patch device manufacturing processes, reduces the welding job amount, has improved productivity effect.Moreover, the optical receiver Surface Mount in the circuit board, with receiving circuit together, be easily receiving circuit and receiving unit design electromagnetic screen part.

Description of drawings

Introduce the present invention in detail below in conjunction with accompanying drawing.

Fig. 1 (a) is that the axis and the light of the light that sends of the optical transmitting set of forward scattering type optical detector of fire smoke connects the synoptic diagram that device receives the angle α of optical axis;

Fig. 1 (b) is the synoptic diagram of the angle α of the axis of the light that sends of the optical transmitting set of back scattering type optical detector of fire smoke and optical receiver optical axis;

Fig. 2 (a) is central axis and the plane that central axis constituted (A) of optical receiver light path and plane (B) the angulation synoptic diagram at circuit place of the optical transmitting set light path of horizontal back scattering type optical detector of fire smoke;

Fig. 2 (b) is the plane that central axis became (A ') of the receiving light path of the central axis of optical transmitting set emission light path of vertical structure back scattering type optical detector of fire smoke and optical receiver and the plane at wiring board place (B ') angulation synoptic diagram;

Fig. 3 a and Fig. 3 b illustrate the size of " d " direction of the detecting area of different scattering angle scattering type photoelectric sensors respectively;

Fig. 4 illustrates the detecting area (drawing the part of shade among the figure) of vertical back scattering type photoelectric sensor and comprises the graph of a relation of the detecting chamber of detecting area;

Fig. 5 is the section of structure of vertical back scattering type optical detector of fire smoke.

Fig. 6 illustrates the sectional view that replaces the light receiving part of plane receiving tube and lens formation with the plug-in unit receiver;

Fig. 7 illustrates paster power valve and leaded light post and replaces the light radiating portion that is made of plug-in unit receiving tube and lens.

Embodiment

Be that 45 ° vertical back scattering type optical detector of fire smoke is an example with the back scattering angle shown in Fig. 5-7 below, describe embodiments of the invention in detail;

As shown in Figure 5, shading window 1 and base 3 constitute a darkroom, are called detecting chamber.Blade on the shading window 1 constitutes optical trap, and it neither hinders entering of smog, has blocked outside ambient light again, makes inside become the darkroom, prevents the top indention of inside of the interference shading window of surround lighting, is used for more effective absorption bias light.Base 3 constitutes a support, supports transmitter and shading window, and it plays fixation, fixing circuit board simultaneously; Structure above it constitutes receive channel in addition, and the light of reception shines on the receiver by this channel.

Transmitter 2 is arranged on the upper part of base 3, and the light that it sends is through lens 4 refractions, and an emission cavity that is full of sawtooth by shading window 1 and base 3 constitute is injected in the detecting chamber.The angle that the central axis of the light that transmitter 2 sends and plane, wiring board place constitute is 0 ° ± 5 °.In order to simplify installation, radiating portion also can be replaced by patch transmitters 11 and leaded light post 10, and the path of the light that penetrates from the leaded light post is the emission light path, and its central axis overlaps with former axis.The central axis of emission light path also can have other sensing, for example obliquely.

Receiver 5 selects the flat table sealing to be contained on the wiring board 8, receives extraneous light by receiver lens 6, and the light of reception is mapped to earlier on the receiver lens 6, focuses on the receiver 5 through lens 6.Plane, lens 6 place is perpendicular to receiving light path.The optical axis center of the optical axis center of receiving light path and emission light path intersects and at 45 ± 5 °, and in same plane, the angle that this plane is become with plane, wiring board place is 90 ° ± 5 °.For the back scattering type photoelectric smoke detector, scattering angle is more little, and is big more to the response output valve of smog, and this angle belongs to less back scattering angle, and is bigger to the response of smog.Color for smog is insensitive, and the smog of different colours is had close output quantity.Inferior, receiving unit can not stop entering of smog as horizontal labyrinth below the shading window flue, improved the directivity of detector.Can be designed to any angle in 0 ° ± 90 ° scopes as required.What receiver 5 of the present invention adopted is that flat table is amplexiformed the receipts device, has reduced the device count of repair welding, has improved production efficiency.Flat table of the present invention is pasted receiver 5 and is also replaced by plug-in unit receiver 9, and its central axis overlaps with former axis.

The longest dimension " d " of the emission path of vertical back scattering type optical detector of fire smoke of the present invention and the crossing detecting area that constitutes of reception path is approaching with the diagonal of detecting chamber section, make full use of the limited space of detecting chamber, saved 25% space.Under the condition of limited of detecting chamber space, can realize doing scattering angle less.In addition, in order to prevent the dust influence, prevent that bias light is too high, the sidewall and the roof of detecting area and detecting chamber leave certain clearance.Baffle plate 7 has blocked other veiling glare effectively to be injected to connect and penetrates in the device, has reduced bias light.

Claims (4)

1. vertical back scattering type optical detector of fire smoke, it comprises the detecting chamber that shading window (1) and base (3) are formed, the emission light path that optical transmitting set (2) and light diversing lens (4) are formed, the receiving light path that optical receiver lens (6) and optical receiver (5) are formed, it is characterized in that: the angle that the plane at the crossing plane of determining of central axis of the central axis of the light of optical transmitting set (2) emission and optical receiver lens (6) and optical receiver (5) reception light and the plate body place of wiring board (8) constitutes is 70 ° of-110 ° of scopes, and the angle that the central axis of emission light path light and the light central axis of receiving light path are constituted is the back scattering angle.

2. according to the vertical back scattering type optical detector of fire smoke of claim 1, it is characterized in that: emission light path and receiving light path intersect the detecting area that forms and are positioned at detecting chamber, and the scattering angle that is constituted is 40 °～90 ° scopes.

3. according to the vertical back scattering type optical detector of fire smoke of claim 1, it is characterized in that: the light radiating portion that optical transmitting set (2) and light diversing lens (4) are formed can be replaced by patch transmitters (11) and leaded light post (10).

4. according to the vertical back scattering type optical detector of fire smoke of claim 1, it is characterized in that: the receiving unit that is made of optical receiver (5) and optical receiver lens (6) can be replaced by plug-in unit receiver (9).

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