JPH0372242A - Method and apparatus for adjusting sensitivity of photoelectric type smoke sensor - Google Patents

Abstract

PURPOSE:To facilitate the setting of sensitivity and adjusting operation while enabling adjustment of sensitivity of a smoke sensor accurately by arranging an auxiliary light emitting element with a variable quantity of light outside a projection area of a projecting element and a light receiving area of a photo detector in a smoke detecting section. CONSTITUTION:A cover 82 of a body 1 of a smoke sensor 1 taken out is removed and a cover 5 is taken off to be replaced with an adjusting cover 9. Then, when the smoke sensor 1 is put into operation, a projection light of a projection element 6 is projected to a light receiving area L2 within a smoke detecting section D and a projection light of an auxiliary light emitting element 94 lighted synchronously though an auxiliary light emitting circuit and these scattered lights are incident into a light receiving element 7. Here, when current flowing through the element 94 is increased little by little by operation of the auxiliary light emitting circuit of the smoke detecting section D, quantity of light projected of the auxiliary light emitting element 94 is increased. With an increase in the element 94, the scattered lights irradiating the light receiving element 7 through the light receiving area L2 is also increased. As a quantity of light incident into the light receiving element 7 increases to reach a fixed value, the smoke sensor 1 shifts to operation state from non-operation state. Thus, unadjusted sensitivity is adjusted from the level of current at the 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 uses a photoelectric element to detect the scattering of light due to smoke.

[Prior Art] A conventional method for adjusting the sensitivity of this type of rechargeable smoke detector includes the invention described in Japanese Patent Publication No. 58-22933, for example.

The adjustment method according to the invention of Japanese Patent Publication No. 5B-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 this type of smoke detector, 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 even in a state where smoke does not flow in, a small amount of light is reflected on the light receiving element 3.

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 sensitivity adjustment plates 4 thus made 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 operates, the suppressed 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. Similarly, to check the sensitivity of an adjusted smoke detector, a large number of prepared sensitivity adjustment plates 4 are inserted 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 4 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 etc. is used in the same way as above, so that each sensor sends out the same detection signal. has been adjusted to.

[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, it is not only difficult to manufacture sensitivity adjustment plates 4 and the like having 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 was made in order to solve the problems of the conventional method of adjusting the sensitivity of rechargeable 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 an auxiliary light emitting element with a variable amount of projected light, which is arranged outside the light emitting area of the light emitting element and the light receiving area of the light receiving element in the smoke detection section, and the amount of projected light of the auxiliary light emitting element is The present invention employs a sensitivity adjustment method and a sensitivity adjustment device for a photoelectric smoke detector, which adjusts the sensitivity of the smoke detector by changing the .

[After attaching the cover for adjusting the function to the main body of an unadjusted smoke detector, if you turn on the auxiliary light emitting element installed outside the light emitting and receiving area in the smoke detector, the emitted light will pass through the light receiving area. and enters the light receiving element. Then, when the amount of current flowing through the lighting circuit of the auxiliary light emitting element is increased little by little, the amount of projected light decreases by 1 and the amount of light incident on the light receiving element also becomes the base value. When the amount of light incident on the light receiving element increases and reaches a certain value, the smoke detector shifts from the non-operating state to the operating state. Moreover, in the case of an analog type, a detection output corresponding to a predetermined smoke density is generated. The sensitivity of the unadjusted smoke detector is adjusted based on the magnitude of the current at this time.

[Embodiment 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 invention, and Figs. 2 and 3 are a bottom view of the optical bench of the device shown in Fig. 1 and its FIG. 3 is a top view of the cover.

In FIGS. 1 to 3, 1 is the main body of the sensor. 2
3 is the base, and 3 is the temporary print. Circuit elements such as resistors and capacitors are provided on the upper surface of the printed circuit board 3. 4 is an optical bench, 5 is its cover, and 6 and 7 are a light emitting 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 4i designates a V-shaped light-shielding column provided near the center of the lower surface of the optical bench 4, 42 designates a large number of light-shielding features such as 1 and 1-shaped shapes formed around the periphery, and 43 designates three positioning holes.

51 and 52 are raised pieces protruding from the upper side of the cover 5;
is three bottles. The raised pieces 5 (and 52 face the light emitting element 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.

The interior of the fitted optical bench 4 and cover 5 forms a labyrinth 40 with surrounding light-shielding pillars 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 of the main body 1 around the insect screen 81, and the cover 82 covers the optical bench 4 from below with the insect screen 81 in between.

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 in the same way as FBS. Therefore, cover 9
On the top surface, there are raised pieces 91 and 92 of the same size in the same position
and three pins 93 are provided.

90 is a sensitivity adjustment mechanism, which includes an auxiliary light emitting element 94 provided on the top surface, a case 95, a lead wire 9B, and an auxiliary light emitting circuit 97 (
6) and a substrate 98. The auxiliary light emitting element 94 is provided outside the light projecting area Ll and the light receiving area Ll of the light receiving element 7, and the projected light intersects with the light receiving area Ll. The auxiliary light emitting element 94 and the case 95 are firmly fixed to the base plate 98 of the cover 9 so as not to move, and if necessary, the case 95 is integrally molded with the base plate 98 of the cover 9. case 95
The auxiliary light emitting element 94 is accommodated therein, and the spread of the projection angle of the light beam projected toward the light receiving area Ll is restricted within a certain range. As shown in FIG. 6, an auxiliary light emitting circuit 97 that controls the amount of light emitted by the auxiliary light emitting element 94, the light emitting time, etc. is supplied with a power source different from the power source for driving the main body of the smoke detector. The auxiliary light emitting circuit 97 is connected to a terminal of the clock signal generating circuit of the main body 1 and is pulse-lit in synchronization with the light projecting element 6. In addition, the lead wire 96
is led out from the board 98 and connected to the auxiliary light emitting circuit 97, and although not shown, is designed to prevent outside light from entering the smoke detection section.

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 square 82 of the main body 1 of the removed smoke detector, remove the cover 5 and remove the fourth
Replace with the adjustment cover 9 shown in the figure. After changing the smoke detector, when the smoke detector is put into operation, the light emitted from the light emitting element 6 and the auxiliary light emitting element 94, which is lit synchronously through the auxiliary light emitting circuit 97, are transmitted to the light receiving area Ll in the smoke detection section. Projection light is projected, and these scattered lights enter the light receiving element 7. The state of the smoke detection section at this time is shown in FIG. 5(A).

Here, the auxiliary light emitting element 94 is activated by operating the auxiliary light emitting circuit 97.
When the current flowing through the auxiliary light emitting element 9 is increased little by little, the auxiliary light emitting element 9
4, the amount of projected light increases. As the amount of light projected by the auxiliary light emitting element 94 increases, the amount of scattered light irradiating the light receiving element 7 via the light receiving area L2 also increases. Further, when the input terminal of the auxiliary light emitting element 94 is increased, the amount of light received by the light receiving element 7 is also increased, and the smoke detector shifts from the non-operating state to the operating state. The point at which this transition occurs is the operating point of the smoke detector.
The amount of current of the auxiliary light emitting element 94 is marked or the amount of current is fixed, and the calibration of the adjustment cover 9 is completed.

After the calibration is completed, the adjustment cover 9 is removed, replaced with the original cover 5 on a standard smoke detector, and then the cover 82 is fitted.

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.

Note that the auxiliary light emitting element 94 attached to the cover 9 for adjustment
shall be used in an area where the current is stable. Also,
If, for example, an infrared light emitting diode in the same wavelength range as the high sensitivity region of the spectral sensitivity characteristic of the light receiving element 7 is used as the light source of the auxiliary light emitting element 94, the amount of current may be weak. FIG. 7 shows the spectral sensitivity characteristics of the light-receiving element 7 and the distribution of the emission intensity of various light emitting diodes, relative to each other, with each peak time being taken as 100%. If a red or yellow visible light emitting diode having a wavelength range different from the high sensitivity region of the spectral sensitivity characteristic of the light receiving element 7 is used as the light source of the auxiliary light emitting element 94, the current will be in a stable region.

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 amplified, and when the smoke concentration exceeds a set value, an activation signal is sent to the receiver, which displays the fire area and sounds the alarms installed in various parts of the house to alert you to the occurrence of a fire. do.

In addition, in the above-mentioned embodiment, the case where the supply current of the auxiliary light emitting element 94 is increased and the transition from the non-operating state to the operating state is selected as the operating point was explained as an example, but when the current is decreased, The operating point may be the transition point from the operating state to the non-operating state. Further, in the same way as the above-described case in which an operation signal is output when a predetermined amount of smoke is detected, an analog type can also be adjusted in which a detection signal is output in accordance with the detected amount of smoke.

[Effects of the Invention] The present invention includes arranging an auxiliary light-emitting element with a variable amount of projected light outside the light-emitting area of the light-emitting element in the smoke detection section and within the light-receiving area of the light-receiving element, and changing the amount of light projected by the auxiliary light-emitting element. A photoelectric smoke detector sensitivity adjustment device was adopted to adjust the sensitivity of the smoke detector.

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. In particular, since the auxiliary light-emitting element of the sensitivity adjustment mechanism uses a wavelength distribution whose wavelength distribution is relatively low in the spectral sensitivity characteristics of the light-receiving element, the rate of change in the amount of light received by the light-receiving element is reduced, increasing detection sensitivity. I can do it.

Therefore, according to the present invention, it is possible to realize a sensitivity adjustment method and a sensitivity adjustment device for a photoelectric smoke detector, which have 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 a connection diagram of an electric circuit used in the method of the embodiment of the present invention, Fig. 7 is an explanatory diagram of the wavelength of the auxiliary light emitting element used in the method of the embodiment of the present invention, and Fig. 8 (A) and (B) are conventional FIG. 2 is an explanatory diagram of a 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, 4'1 is a V-shaped light shielding column, 42 is a 1-shaped light shielding column, 4
3 is a positioning hole, 51, 52 and 91, 92 are raised pieces,
53 and 93 are pins, D is smoke detection part, Ll is light emitting area, L2 is light receiving area, 8H is insect screen, 82 is cover, 94 is auxiliary light emitting element, 95 is case, 96 is lead wire, 97 is auxiliary The light emitting circuit 98 is a substrate.

Claims (4)

[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 a smoke detector configured to detect smoke by receiving light, an auxiliary light emitting element whose projected light amount is variable is arranged outside the light emitting area of the light emitting element and the light receiving area of the light receiving element in the smoke detection section, A method for adjusting the sensitivity of a photoelectric smoke detector, characterized by adjusting the sensitivity of the smoke detector by changing the amount of light projected by an auxiliary light emitting element. (2) The auxiliary light-emitting element has a wavelength range in which it emits light, which is outside the high-sensitivity region of the spectral sensitivity characteristics of the light-receiving element;
2. The method for adjusting the sensitivity of a photoelectric smoke sensor according to claim 1, wherein the light emitting current of the auxiliary light emitting element is in a stable region. (3) 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 emitted from the light emitting element, and smoke enters the optical bench. 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; an auxiliary light emitting element located on the inner surface on the side of the smoke detection part, which is located outside the light emitting area of the light emitting element and the light receiving area of the light receiving element, and changes the amount of light emitted toward the light receiving area; and adjusting the amount of light emitted by the auxiliary light emitting element. A sensitivity adjustment device for a photoelectric smoke detector, comprising: an auxiliary light emitting circuit that performs the following steps: (4) Sensitivity adjustment of the photoelectric smoke detector according to claim (3), wherein the auxiliary light emitting element emits light in a wavelength region outside the high sensitivity region of the spectral sensitivity characteristic of the light receiving element. Device.