JP2715164B2 - Photo interrupter for smoke detection - Google Patents

Description

The present invention is used for starting a flame alarm in the event of a fire or for starting an air purifier when cigarette smoke or the like becomes thick. A photointerrupter, which is a smoke detector.

(Prior art) Conventionally, in order to activate a flame alarm in the event of a fire or to activate an air purifier when the smoke of cigarettes becomes dense, smoke is detected in a fire or cigarette smoke. More often, detection is performed by a detector.

Many proposals have been made for this smoke detector. For example, an ionization type smoke detector according to Japanese Utility Model Publication No. 63-49826, a scattered light smoke detector according to Japanese Utility Model Publication No. 63-49828, and the like are used.

(Problems to be Solved by the Invention) Each of the above sensors has a large device, and it is difficult to sufficiently cope with the recent trend of miniaturization.
In addition, there is a disadvantage that the price is inevitably high and the range of use is limited.

(Means for Solving the Problems) The present invention has been made in view of such conventional problems, and is a photointerrupter which is a smoke detector which is simple in structure, inexpensive, and has few malfunctions. It is intended to provide.

In order to achieve this object, the present invention provides two mounting holes drilled at the required depth on the same axis on the left and right sides, and at appropriate intervals near the center on the front and rear sides, and on the axis. A rectangular cubic holding substrate made of a material having a property of blocking and absorbing light, comprising: a pair of window holes formed so as to be perpendicular to each other and communicating with the both mounting holes. The light projecting and light receiving elements are fitted to each other through the two mounting holes to form a detecting section, and the light projected from the light projecting element is scattered by smoke flowing into the smoke detection area of the detecting section. A smoke interrupt photodetector characterized in that the scattered light generated thereby is incident on the light receiving element and smoke is detected based on the light receiving output of the light receiving element.

(Operation) Since the photointerrupter has a simple structure and is easy to manufacture, and since the parts used are also common,
It can be produced at low cost.

In addition, the photo interrupter has a structure that limits the optical path of the light emitting and receiving elements to limit the smoke detection area to the required range, so that scattered light can be detected efficiently, and furthermore, the influence of scattered light and reflected light outside the smoke detection area is prevented. Malfunction can be reduced.

Further, since the photointerrupter holds the light emitting / receiving element in a state of being completely covered, even if the photointerrupter is used for a long period of time, it is possible to prevent the surface from being stained which may cause deterioration.

In addition, the photo interrupter is less susceptible to scattered and reflected light outside the smoke detection area, and also prevents contamination of the light emitting and receiving elements.
The reduction of the ratio is small.

In addition, since the photointerrupter can obtain a large S / N ratio, it is possible to connect an amplifier having a high amplification ratio, and a smoke detector with high sensitivity can be manufactured.

(Embodiment) The present invention will be described in detail below based on one embodiment shown in FIGS. Reference numeral 1 denotes left and right side surfaces 2, 2 ', two mounting holes 3, 4 drilled on the same axis X at a required depth and diameter, and front and rear side surfaces.
A partition wall 6 of an appropriate thickness is placed near the center at 5,5 ', and the required length in the direction of the axis X is formed so as to be perpendicular to the axis X and communicate with the mounting holes 3 and 4, respectively. This is a rectangular plate-shaped holding base made of black ABS synthetic resin having light blocking and absorbing properties with both rectangular window holes 7, 8. Reference numeral 9 denotes a screw hole formed in the bottom surface 10 of the holding base 1 for appropriately fixing the holding base 1.

Reference numeral 11 denotes a photointerrupter in which a light emitting diode LED as a light emitting element 12 and a photodiode PD as a light receiving element 13 are fitted in both mounting holes 3 and 4 of the holding base 1 so as to form a detecting section. . Reference numeral 14 is a lead wire for the light emitting diode LED and the photodiode PO.

As shown in FIGS. 3 and 4, the photo-interrupter 11 emits light emitted by applying a predetermined current to the light-emitting diode LED to the periphery of the partition 6 of the holding base 1 through the light-emitting window 7. The photodiode PD projects the light, scatters the light scattered by the smoke flowing into the smoke detection area 15 (described later) formed around the partition wall 6 and causes the scattered light to enter through the light receiving window 8, and generates the photodiode PD that receives the light. The detected light output is detected to detect smoke. This light receiving output is
The amplified signal is output as a detection signal after being amplified by an appropriate amplifier connected to.

The smoke area 15 passes through the light emitting window 7 and the light emitting diode LE.
A region where light is projected from D and a region where light can be received by the photodiode PD via the light receiving window 8 is interlaced. In this space, the photo interrupter 11 has a detection sensitivity. Are formed near the outside of the partition wall 6 on the front and rear side surfaces of the partition wall 6.

A stack of two of the photointerrupters 11
FIG. 6 shows the results of trial production and smoke detection of a smoke detector connected to the amplifier shown in FIG. In FIG. 6, C-1 is the smoke density expressed in mg of fine dust per cubic meter of smoke measured and converted by a dust meter, and C-2 is the output voltage of the smoke detector corresponding to the smoke density of C-1. V.

The output voltage of the smoke detector rises substantially in proportion to the smoke density and accurately detects the smoke density. The smoke detector has extremely good characteristics as compared with other existing smoke detectors.

The photointerrupter 11 restricts the optical path by the opening shapes of the mounting holes 3 and 4 of the light emitting and receiving elements 12 and 13 provided in the holding base 1 and the opening holes 7 and 8 for the light emitting and receiving. , Smoke detection area 15
Is limited to a necessary range near the outside of the partition 6 near the center of the holding base 1 so that the scattered light due to smoke can be detected efficiently and the influence of the scattered light outside the smoke detection area 15 can be obtained. And a malfunction due to the reflected light incident on the peripheral member including the protective container when incorporated in the device can be reduced. This is because the smoke detector manufactured for the same purpose as the conventional one simply has an angle to the optical axis, so it is susceptible to reflected light and the like when installed in a space close to peripheral members This is extremely advantageous when the photointerrupter 11 is installed in a similar space as compared with the conventional product.

The photo-interrupter 11 also has two mounting holes 3, 4 into which the light emitting / receiving elements 12, 13 are fitted to a required depth.
Since the device 13 is held in a completely covered state, it is possible to reliably prevent the surfaces of both the devices 12 and 13 from being contaminated even when used for a long period of time.

It is also known that the photointerrupter 11 has a smaller scattering angle when light passes through an aerosol in which very small particles such as smoke are dispersed as compared to large particles. The light projected from the element 12 is
The structure is such that the light is not directly incident on the light source, so that the deviation of the projection / reception angle can be made extremely small, so that the scattered light can be detected efficiently.

In this case, the photointerrupter 11 has a simple structure and is easy to manufacture, and since the components used are also general, the photointerrupter 11 can be produced at low cost.

Also, the photo interrupter 11 has a structure in which the light path of the light emitting / receiving element can be restricted to limit the smoke detection area 15 to a necessary range.
Since the scattered light due to smoke can be detected efficiently, and the influence of scattered light and reflected light in areas other than the smoke detection area can be prevented to reduce malfunctions, it has extremely excellent performance.

Also, since the photointerrupter 11 holds the light emitting / receiving elements 12 and 13 in a completely covered state, it prevents contamination of the surface which may cause deterioration even when used for a long period of time. become longer.

In addition, the photo interrupter 11 is less susceptible to scattered light and reflected light outside the smoke detection area, and also prevents contamination of the light emitting and receiving elements 12 and 13, so that the S / N ratio can be maintained even after long-term use. The performance is stable with little decrease.

Further, since the photointerrupter 11 can obtain a large S / N ratio, it is possible to connect an amplifier having a high amplification factor, and a smoke detector with high sensitivity can be manufactured.

In the above embodiment, the holding base 1 is made of black ABS.
Although made of synthetic resin, other synthetic resin may be used as long as it has a specific property equivalent to ABS with light blocking and absorbing properties instead of ABS, and it can be made into a rectangular plate shape. Formed
Both mounting holes 3 and 4 are provided on the same axis X, and both window holes 7 and 8 are provided.
May be provided not perpendicular to the axis X, but may be a rectangular cube similar to this.

In addition, although the light emitting diode 12 is used for the light emitting element 12 and the photodiode PD is used for the hole receiving element 13, other elements may be used instead of the light emitting diode and the photodiode PD as long as they have the same characteristics as the light emitting diode LED and the photodiode PD. good.

(Effects of the Invention) The present invention has the above configuration, and thus has the following effects.

(1) Since it can be produced at low cost and can be easily mass-produced, it can be provided to customers at low cost.

(2) It has excellent performance because it can efficiently detect scattered light due to smoke, and can reduce the number of malfunctions by preventing the influence of reflected light. Can be.

(3) Since the light-emitting and light-receiving elements are completely covered, no deterioration phenomenon occurs even when used for a long period of time, the service life thereof is extremely long, and the cost is excellent.

(4) Since the S / N ratio is small and the performance is stable even after long-term use, it is extremely reliable.

(5) Since the S / N ratio can be increased, a highly sensitive smoke detector can be manufactured, and the range of use can be expanded.

(6) The above items together contribute to an increase in sales and an increase in corporate profits.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention, wherein FIG. 1 is a holding base, (a) is a front view, (b) is a plan view, (c) is a right side view, and FIG. And FIG. 4 is a photo interrupter,
2 is a sectional view taken along the line AA, FIG. 3 is a sectional view taken along the line BB, FIG. 4 is a simplified view for explaining the function, and FIGS. 5 and 6 are smoke detection examples of an application of the embodiment. FIG. 5 is a circuit diagram, and FIG. 6 is measured smoke data. DESCRIPTION OF SYMBOLS 1 ... Holding base, 2 ... Left side, 2 '... Right side 3,4 ... Mounting hole, 5 ... Front side, 5' ... Rear side 6 ... Partition wall, 7, 8 ... Window Hole 11 Photo interrupter 12 Light emitting element 13 Light receiving element 15 Smoke detection area X X Axis LED LED Light emitting diode PD Photo diode

Claims (4)

(57) [Claims] 1. Both mounting holes drilled on the left and right side surfaces on the same axis at a required depth, and at appropriate intervals close to the center on the front and rear side surfaces and perpendicular to the axis. The two mounting holes are provided on a rectangular cubic holding base made of a material having a light shielding property and an absorbing property, with both window holes formed so as to communicate with the two mounting holes, respectively. A light-receiving element is attached to the light-receiving element through the light-receiving element to form a detection unit, and light emitted from the light-emitting element is scattered by smoke flowing into the smoke detection area of the detection unit. Wherein the light is incident on the light receiving element and smoke is detected based on the light receiving output of the light receiving element. 2. The photointerrupter according to claim 1, further comprising a rectangular window having a required length in the axial direction. 3. A photo-interrupter according to claim 1, further comprising two mounting holes formed with a diameter such that said light-emitting and light-receiving elements are closely fitted. . 4. The method according to claim 1, wherein a holding base made of black ABS synthetic resin is used.
The photointerrupter according to any one of the above items.