CN2938249Y

CN2938249Y - Simple backward scattering optical darkroom

Info

Publication number: CN2938249Y
Application number: CN 200620071830
Authority: CN
Inventors: 王殊; 窦征
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-05-26
Filing date: 2006-05-26
Publication date: 2007-08-22
Anticipated expiration: 2016-05-26

Abstract

The utility model relates to a retrodiffusion-based simple optics darkroom which pertains to the fire technology field. The optics darkroom consists of a sun lounge and a maze; masking blades are provided around the maze; a transmitting valve room for installing a transmitting valve and a receiving tube room for installing a receiving tube are fixed and arranged on the sun lounge; the angle between the transmitting valve and the optical axis of the receiving tube is less than 90 degree; the distance between the transmitting valve room and the optical center is less than that betwwen the receiving tube room and the optical center; a part of the receiving tube room is blotted out by the front end face of the transmitting valve room. Experiments show that the utility model can equably response to various test fires including test fires of a third kind and a fourth kind to meet the requirements of national standard on the fire detector. The utlity model has a simple structure with convenient technics.

Description

Simple and easy back scattering type optical dark room

Technical field

The utility model relates to a kind of sensing element of photoelectric smoke detector, specifically is used for the optical dark room based on the back scattering principle of smoke detection, belongs to the fire prevention field.

Background technology

The scattering type photoelectric smoke fire detector can be divided into forward scattering type and back scattering type, and the angle according to optical dark room light emitting devices optical axial in the detector and light receiving element optical axial defines usually: angle is called the forward scattering type greater than 90 ° of persons; Angle is called the back scattering type less than 90 ° of persons.

The forward scattering type photoelectric smoke detector of widespread use at present can respond well to the 1st kind of test fire SH1 and the 2nd kind of test fire SH2 of standard GB 4715-2005 regulation, but the response sensitivity to the 3rd kind of test fire SH3 and the 4th kind of test fire SH4 is low, does not respond the 3rd kind and the 4th kind of test fire under the detector sensitivity that is suitable for China's request for utilization.If the detection sensitivity of the forward scattering type photoelectric smoke detector of widespread use is at present improved, can accomplish to respond all 4 kinds of test fires, but because response sensitivity is even inadequately, under the influence and restriction of factors such as the use habit of China, running environment, might produce the fire alarm of a lot of mistake, therefore be not suitable for the actual request for utilization of China.

Summary of the invention

The purpose of this utility model is: proposition can be under the detection sensitivity that is fit to China's application request, responds 4 kinds of test fires and back scattering type optical dark room simple in structure, that price is low equably.

The simple and easy back scattering type of the utility model optical dark room is made up of light chamber and labyrinth, described labyrinth circumferential distribution has cover blade, indoor power valve chamber that power valve is installed and the receiving tube chamber that receiving tube is installed of fixedly being equipped with of described light, the angle of described power valve and receiving tube optical axial is less than 90 ° (experiment shows with 35 °-70 ° for good), the distance of optical centre is arrived less than the distance of receiving tube chamber to optical centre in described power valve chamber, and power valve chamber front end face is partial occlusion to the receiving tube chamber.

The distance of optical centre is arrived in the power valve chamber less than the receiving tube chamber to the distance of optical centre, can reduce northern background signal, and power valve chamber front end face rationally blocking part, receiving tube chamber, the sub-fraction " sight line " that can make the outer wall of power valve chamber " block " receiving tube, thus the better compromise of sensitivity and background signal obtained.

During work, in the near zone formation optical sensitive district of power valve and receiving tube optical axial intersection (being optical centre).Enter optical dark room as smog, when arriving this sensitizing range, scattering takes place in smoke particle under the infrared beam irradiation from power valve, and scattered light enters receiving tube, converts electric signal to, by judging fire hazard after the calculation process.Experiment shows, adopt said structure of the present utility model after, can respond more equably and comprise the 3rd and the various test fires of 4 kind of test fire, thereby satisfy the requirement of national standard, and it is simple in structure fire detector, technology is convenient.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is the structural representation of an embodiment of the utility model.

Fig. 2 is the cut-open view of Fig. 1.

Fig. 3 is the local structure for amplifying synoptic diagram of Fig. 2 power valve chamber and receiving tube chamber.

Embodiment

Embodiment one

The simple and easy back scattering type optical dark room of present embodiment is combined by light chamber 1 and labyrinth 2 as shown in Figure 1.The circle distribution in labyrinth 2 " V " type cover blade, its effect are to allow smog to free in and out, and prevent that simultaneously external environment light from directly injecting optical dark room (referring to Fig. 2).Certainly the labyrinth of other form also can be adopted.Fixed transmission pipe chamber 3, receiving tube chamber 4 on the base plate 7 of light chamber 1.Infrared transmitting tube 5 and infrared receiving tube 6 (referring to Fig. 3) are installed respectively in power valve chamber 3 and the receiving tube chamber 4.

The optical axial EO of infrared transmitting tube 5 and the optical axial PO of receiving tube 6 intersect at the O point, and this point is called optical centre.The folded angle θ of two optical axial EO and PO is 45 ° (can be 35 ° to 70 °).

In the light chamber 1, launching light beam around the optical centre O and receiving the diamond-shaped area that intersects at the visual angle is optical sensitive district (referring to Fig. 2).When smog enters optical dark room and arrives this sensitizing range, scattering takes place under the infrared beam irradiation of smoke particle power valve 5 emissions in power valve chamber 3, scattered light enters receiving tube chamber 4 and is received by infrared receiving tube 6, converts electric signal to.This signal strengthens with the increase of smokescope.This signal is carried out can judging fire hazard after the calculation process.

Enforcement below in conjunction with Fig. 3 this patent is described further.

As shown in Figure 3, power valve chamber 3 is 4 one distance L in " in advance " receiving tube chamber (L=0.4-2mm) on the position, promptly power valve chamber 3 front end faces to optical centre O apart from Se than receiving tube chamber 4 front end faces to optical centre O apart from the short 0.4-2mm of Sp.

Power valve chamber 3 cylindrical outer walls " have blocked " sub-fraction of receiving tube chamber 4 cylinder shape inner walls, " amount of blocking " δ=0.1-1.0mm.

More than two measures help under the prerequisite that guarantees sensitivity, to reduce background signal.

The head of power valve 5 and receiving tube 6 is managed the distance of

chamber

3 and 4 front end faces separately in the 1-4mm scope to them.Simultaneously, the wall thickness of pipe chamber is no more than 1mm, makes that power valve 5 and receiving tube 6 are close as far as possible.So just guaranteed that optical dark room has sufficiently high sensitivity.

In order to reduce the assembly cost of die cost and optical dark room, two molds are only used in light chamber (power valve chamber 3, receiving tube chamber 4 and light chamber base plate 7), it is top one mold of power valve chamber 3 and receiving tube chamber 4, the bottom of power valve chamber 3, receiving tube chamber 4 and base plate 7 mold, thereby form power valve chamber 3 and receiving tube chamber 4 and fasten the structure that the bottom of power valve chamber 3, receiving tube chamber 4 and base plate 7 are connected as a single entity respectively by upper and lower two parts.

Experiment showed, that the simple type back scattering type optical dark room of present embodiment can respond 4 kinds of test fires of national Specification fully equably under the detection sensitivity that is fit to China's application request, is a kind of solution of economy.

Claims

1. back scattering type optical dark room, combine by light chamber and labyrinth, described labyrinth circumferential distribution has cover blade, indoor power valve chamber that power valve is installed and the receiving tube chamber that receiving tube is installed of fixedly being equipped with of described light, the angle of described power valve and receiving tube optical axial is less than 90 °, it is characterized in that: less than the distance of receiving tube chamber front end face to optical centre, power valve chamber front end face is to receiving tube chamber partial occlusion to the distance of optical centre for described power valve chamber front end face.

2. according to the described back scattering type of claim 1 optical dark room, it is characterized in that: the angle of described power valve and receiving tube optical axial is 35 °-70 °.

3. according to claim 1 or 2 described back scattering type optical dark rooms, it is characterized in that: the short 0.4-2mm of distance of optical centre is arrived in described power valve chamber than receiving tube chamber to the distance of optical centre.

4. according to claim 1 or 2 described back scattering type optical dark rooms, it is characterized in that: described power valve chamber is 0.1-1.0mm to the amount of blocking of receiving tube chamber.

5. according to claim 1 or 2 described back scattering type optical dark rooms, it is characterized in that: the head of described power valve and receiving tube is 1-4mm to the distance of respective tube chamber front end face.

6. according to claim 1 or 2 described back scattering type optical dark rooms, it is characterized in that: fixed transmission pipe chamber and receiving tube chamber on the base plate of described smooth chamber, described power valve chamber and receiving tube chamber are fastened by upper and lower two parts respectively and form, and the bottom and the base plate of described power valve chamber and receiving tube chamber are connected as a single entity.