JPH0372243A - Method and apparatus for adjusting sensitivity of photoelectric type smoke sensor - Google Patents

Abstract

PURPOSE:To facilitate the setting of sensitivity and adjusting operation and moreover, enable the adjusting of sensitivity of a smoke sensor precisely and the checking of operation by providing a condenser lens and a stop on the photodetecting surface side of a photo detector in a smoke detecting section. CONSTITUTION:A cover 82 of a smoke sensor body 1 taken out is removed and a cover 5 is taken off to be replaced with a cover 9 for adjustment. Thereafter, when the sensor 1 is put into operation, a noise light in a photo detecting area L2 a smoke detecting section D is condensed and incident into a photo detector 7 through a stop 95. Here, as the stop 95 is operated to be opened little by little, a quantity of luminous flux passing through an optical path within the stop 95 is increased so that scattered light irradiating the photo detector 7 through the photo detecting area L2 increases. Then, when a quantity of light incident into the photo detector 7 increases to reach a fixed value, the operating state of the smoke sensor 1 is inverted. Or a detection output corresponding to a density of smoke is generated. This enables the adjusting of sensitivity of a smoke sensor 1 yet to be adjusted and the checking for operation of the smoke sensor 1 adjusted from the opening of the stop at this moment.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sensitivity adjustment method and a sensitivity adjustment device for a photoelectric smoke detector that detects fire by detecting light scattering due to smoke using a photoelectric element. It is.

[Prior Art] A conventional method for adjusting the sensitivity of this type of photoelectric smoke detector includes the invention described in Japanese Patent Publication No. 5B-22933, for example.

The adjustment method of the invention of Japanese Patent Publication No. 5 [F-22933] is carried out with a configuration as shown in FIGS. 7(A) and 7(B).

In FIG. 7A, 1 is a dark box, 2 is a light source, 3 is a light receiving element, and 4 is a sensitivity adjustment plate. Generally, in the dark box 1 of the smoke detector of this scale, the light from the light source 2 is 1 on the surface of the component.
Noise light that is reflected sequentially or several times is included, and a small amount of light is incident on the light receiving element 3 even in a state where smoke does not flow in.

When adjusting the sensitivity using such a device, a large number of sensitivity adjustment plates 4 having different reflectances are prepared in advance, and a smoke detector whose sensitivity has already been set is prepared. The produced sensitivity adjustment plates 4 are inserted into the adjusted smoke detector in order of decreasing reflectance, and the light source 2 is turned on to put it into operation. Then, when the light receiving element 3 receives a predetermined amount of light due to the increase in noise light caused by the sensitivity adjustment plate 4 and the smoke detector is activated, the inserted adjustment plate 4 is set as the standard sensitivity adjustment plate 4.

Next, this standard sensitivity adjustment plate 4 is inserted into an unadjusted smoke detector, and the sensitivity of the smoke detector is gradually increased from the lowest value to the highest. Then, when the state changes from the non-operating state to the operating state, the adjustment point is fixed and the sensitivity adjustment is completed. In the same way, you can also check the sensitivity of your calibrated smoke detector! A large number of sensitivity:A adjusting plates 4 are pushed in one after another, and the operating point at that time is regarded as the sensitivity, and the check is completed.

7B shows a standard sensitivity adjustment case 5 that corresponds to the standard sensitivity adjustment plate 4 shown in FIG. 7A. (B) In the method shown in the figure, a large number of standard sensitivity adjustment cases 5 are prepared in advance, the inner surfaces of which are coated with paint whose shading changes in stages. Then, as in the case of the standard sensitivity adjustment plate 4, sensitivity adjustment and sensitivity check are performed by changing the standard sensitivity adjustment case 5 one after another and increasing or decreasing the noise light to find the operating point. Also, in the case of so-called analog photoelectric smoke detectors that output a detection signal proportional to the amount of smoke detected, an adjustment plate or the like is used in the same way as above, so that each sensor sends out the same detection signal: A is adjusted.

[Problems to be Solved by the Invention] As mentioned above, in order to adjust the sensitivity of the conventional on/off type or analog type photoelectric smoke detector, a large number of sensitivity adjustment plates 4 and standard sensitivity are used to change the amount of scattered light. Adjustment case 5 is used. These sensitivity adjustment plates 4 and standard sensitivity adjustment cases 5 are replaced one after another to perform sensitivity adjustment and sensitivity checks. For this reason, not only is it difficult to produce the power adjustment plate 4 and the like with different amounts of scattered light, but also a large number of adjustment samples must be prepared. Further, since sample handling and detection operations are repeated, adjustment and checking operations are extremely troublesome. Although the operation becomes easier by reducing the number of samples such as the sensitivity adjustment plate 4, there are problems such as lower surface detection accuracy and failure to meet standards.

The present invention has been made in order to solve the problems of the conventional method of adjusting the sensitivity of photoelectric smoke detectors as described above.It is easy to set and adjust the sensitivity, and has a simple configuration that eliminates variations. The object of the present invention is to realize a sensitivity adjustment method and a sensitivity adjustment device for a photoelectric smoke detector.

[Means for Solving the Problems] The present invention provides a condenser lens and an aperture on the light-receiving surface side of a light-receiving element in a smoke detection section, and the noise light in the smoke detection section is collected by the condenser lens, and the aperture is adjusted. The sensitivity adjustment method and sensitivity':'J8 adjustment device for a photoelectric smoke detector are adopted in which the sensitivity of the smoke detector is adjusted by 511 by changing the amount of light received by the light receiving element.

[Operation] When the light-emitting element is turned on after attaching the cover for adjusting the sensitivity to the body of the smoke detector whose sensitivity has been adjusted, the condensing lens provided on the light-receiving surface of the light-receiving element in the smoke detection section The noise light is focused and irradiated onto the light receiving element. Then, as the aperture is gradually opened, the amount of light incident on the light receiving element increases accordingly. When the amount of light incident on the light receiving element increases and reaches a certain value, the operating state of the smoke detector is reversed. Alternatively, a detection output corresponding to a predetermined smoke density is generated. Based on the aperture opening at this time, the sensitivity of unadjusted smoke detectors is adjusted and the operation of adjusted smoke detectors is checked.

[Embodiments of the Invention] Fig. 1 is an explanatory diagram of the configuration of a photoelectric smoke detector for explaining the method of the embodiment of the present invention, and Figs. 2 and 3 are bottom views of the optical bench of the apparatus shown in Fig. FIG. 3 is a top view of the cover.

In FIGS. 1 to 3, 1 is the main body of the sensor. 2
is a base, and 3 is a printed board. Circuit elements such as resistors and capacitors are provided on the upper surface of the printed board 3. 4 is an optical bench, and 5 is its force l<-6 and 7 are a light projecting element and a light receiving element. The optical bench 4 and cover 5 have a combined structure and are molded from black synthetic resin into a substantially hollow cylindrical shape. Reference numeral 41 indicates a V-shaped light-shielding column provided near the center of the lower surface of the optical bench 4, 42 indicates a large number of light-shielding columns such as letter 1 and letter 0 shapes formed around the periphery, and 43 indicates three positioning holes.

51 and 52 are raised pieces protruding from the upper side of the cover 5;
has three pins. The raised pieces 51 and 52 face the light emitting cable 6 and the light receiving element 7, respectively, and the bin 53 is located in the positioning hole 4.
Corresponds to 3. Then, the optical bench 4 and cover 5 are fitted from above and below at a predetermined position by inserting the pin 53 into the positioning hole 43, and both the light projecting element 6 and the light receiving cable 7 are housed in a storage chamber having a window.

Inside the fitted optical bench 4 and cover 5, a labyrinth 40 is formed by surrounding light-shielding columns 42, and air, i.e.,
It constitutes a smoke detection section that allows smoke to circulate but blocks external light. The optical axes of the light projecting element 6 and the light receiving element 7 housed in the storage chamber intersect, so that direct light from the light projecting element 6 does not enter.

81 is an insect screen made of thin metal, 82 is a cover for the main body 1 around the insect screen 81, and the cover 82 sandwiches the insect screen 81 and covers the optical bench 4 from below.

Figure 4 is a top view of the adjustment cover used in the method according to the present invention, Figures 5 (A) and (B) are explanatory diagrams of the method according to the present invention, and (A) is the smoke detector (B) is a perspective view of the cover 9.

9 in FIG. 4 is a cover for adjustment. Adjustment cover 9
is the cover 5 described above except for the sensitivity adjustment mechanism described next.
It is made with the same structure. Therefore, on the top surface of the cover 9, there are raised pieces 91, 92 and 3 of the same size at the same position.
A book pin 93 is provided.

90 is a sensitivity adjustment mechanism, and a condensing lens 9 provided on the top surface
4, an aperture 95 and a substrate 96.

Both the condensing lens 94 and the aperture 95 are provided on a substrate 96 corresponding to the light receiving surface of the light receiving element 7. Condensing lens 9
4 and the aperture 95 are firmly fixed to the base plate 96 of the cover 9 so as not to move, and are integrally molded with the base plate 9G of the cover 9 if necessary. The condensing lens 94 focuses the noise light within the smoke detection section, and the aperture 95 increases or decreases the amount of light incident on the light receiving element 7 by opening and closing the optical path through which the light beam condensed by the condensing lens 94 passes. The aperture operation of the diaphragm 95 is performed, for example, by a driving means that magnetically couples the inside and outside of the smoke detection section, so that outside light does not enter into the smoke detection section, although this is not shown.

The sensitivity adjustment method of the present invention using such a device will be described next.

Take out a standard smoke detector that has already been calibrated and has its detection sensitivity set. After removing the cover 82 of the main body 1 of the smoke detector taken out, remove the cover 5 and remove the m4
The adjustment cover 9 shown in the figure and FIG. 5(B) is used instead. The state when the clothes have been changed is shown in FIG. After changing the smoke detector, when the smoke detector is activated, the noise light in the light receiving area L2 in the smoke detector is focused and enters the light receiving element 7 through the aperture 95 [Figure 5 (A]). Here, when the aperture 95 is opened little by little by operating the aperture 95, the amount of light passing through the optical path inside the aperture 95 increases.As the amount of light passes through the light receiving area L2, Scattered light that illuminates the light receiving element 7 also increases.Furthermore, the aperture 95
When the smoke detector is operated to open, the amount of light received by the light-receiving element 7 increases, and the smoke detector shifts from a non-operating state to an operating state. With this transition as the operating point of the smoke detector, the opening degree of the diaphragm 95 is marked, or the opening degree of the diaphragm 95 is fixed, and the calibration of the adjustment cover 9 is completed. When the calibration is completed, the adjustment cover 9 is removed, the original cover 5 is replaced with the standard smoke detector, and the cover 82 is fitted, thereby completing the adjustment operation.

Then, using the calibrated adjustment cover 9, the sensitivity of the unadjusted smoke detector can be adjusted and the operation of the adjusted smoke detector can be checked by operations similar to the conventional method described above.

The main body 1 of the smoke detector whose sensitivity has been adjusted and checked in this manner is attached from below to a base (not shown) which is attached to a ceiling or the like and to which wiring has been connected. The smoke detectors on each floor are connected in parallel via wiring to a receiver (not shown) for each line.

Now, when a fire breaks out indoors, combustion products (hereinafter referred to as smoke) rise and flow into the smoke detection area of the main body 1 on the ceiling. on the other hand,
The light projecting element 6 in the optical bench 4 is periodically pulsed. Then, the light projected from the light projecting element 6 is scattered by the incoming smoke, the amount of scattered light in the light receiving area L2 increases, and the light receiving element 7 detects this increased scattered light. Light receiving element 7
The detection signal is widened, and when the smoke concentration exceeds a set value, an activation signal is sent to the receiver, which displays the fire area and sounds alarms installed in various places indoors to warn of the outbreak of fire. inform.

In addition, in the above-mentioned embodiment, the operation point is selected as the operating point when the smoke detector moves from the non-operating state to the operating state while gradually opening the diaphragm 95, but when the diaphragm 95 is gradually closed. The operating point may be the transition point from the operating state to the non-operating state. In addition, in the case of a so-called analog type photoelectric smoke detector that generates a detection output corresponding to the concentration of smoke, when the adjustment cover 9 is attached, the amount of light incident on the light receiving cable 7 is adjusted by the aperture 95. Then, adjust the sensitivity so that the detection output of each sensor is equal.

[Effects of the Invention] The present invention provides a condensing lens and an aperture on the light-receiving surface side of the light-receiving element in the smoke detection section, and condenses the light incident on the light-receiving element by the condenser lens, and reduces the amount of light received by the aperture. We adopted a photoelectric smoke detector sensitivity adjustment device that adjusts the sensitivity of the smoke detector by 2J. As a result, the sensitivity can be adjusted by changing the cover of the optical bench and changing the amount of light projected by the auxiliary light emitting element, so the adjustment mechanism is extremely simple and the adjustment operation is easy. especially,
Since the condensing lens of the sensitivity adjustment mechanism is used to focus weak light, there is an advantage that the sensitivity can be adjusted by increasing the amount of light received by the light receiving element while consuming low power.

Therefore, according to the present invention, it is possible to realize a sensitivity adjustment method for a photoelectric smoke detector having various features such as easy adjustment.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a photoelectric smoke detector for explaining the method according to the embodiment of the present invention, FIGS. 2 and 3 are a bottom view of the optical bench and a top view of the cover of the device in FIG. The figure is a top view of the adjustment cover used in the method according to the present invention, and FIGS. 5(A) and 5(B) are explanatory views of the method according to the present invention.
A) is an explanatory diagram of the smoke detection section, (B) is a perspective view of the cover 9,
FIG. 6 is an explanatory diagram of the operation of the method according to the present invention, and FIG. 7 is (A
) (B) is an explanatory diagram of a conventional sensitivity adjustment method. In the figure, 1 is the main body of the smoke detector, 2 is the base, 3 is the printed board, 4 is the optical stand, 5 is the optical stand cover 6 is the light emitting element,
7 is a light receiving element, 9 is a cover for adjustment, 40 is a labyrinth, 41 is a V-shaped light shielding column, 42 is a 1-shaped light shielding column, 43
are positioning holes, 51, 52 and 91, 92 are raised pieces, 53
and 93 are pins, D is a smoke detector, LI is a light emitting area, L2 is a light receiving area, 81 is an insect screen, 82 is a cover, 94 is a condensing lens, 9
5 is an aperture, and 96 is a substrate. Meat 1 Figure 2 Noodles 3 Figure 4 Figure 6

Claims (2)

[Claims] (1) A light emitting element and a light receiving element outside the light emitting area of the light emitting element are arranged in a smoke detection section, and the scattered light of the light projected from the light emitting element due to smoke flowing into the smoke detection section is transmitted to the light receiving element. In the smoke detector configured to detect smoke by receiving light from the smoke detector, a condenser lens and an aperture are provided on the light-receiving surface side of the light-receiving element in the smoke detection section, and the smoke detection element is directed to the light-receiving element by the condenser lens. A method for adjusting the sensitivity of a photoelectric smoke detector, characterized in that the sensitivity of the smoke detector is adjusted by condensing noise light inside the smoke detector and changing the amount of light received by the aperture. (2) Smoke enters when a cover is attached to the optical bench that is equipped with a light emitting element and a light receiving element that is outside the light emitting area of the light emitting element and receives scattered light due to smoke of light emitted from the light emitting element. A sensitivity adjustment device for a smoke detector comprising a smoke detecting section that blocks external light, the device comprising: an adjustment cover having the same shape as the cover and detachable from the optical bench; A condenser lens and a diaphragm are fitted on the inner surface of the smoke detection section side to the light receiving surface side of the light receiving element of the optical bench and change the amount of noise light scattered within the smoke detection section. Sensitivity adjustment device for photoelectric smoke detectors.