JPS595398A - Photoelectric smoke sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to a photoelectric smoke detector.

As shown in FIG. 1, this photoelectric smoke detector detects the scattered light/Th of the light emitted from the light emitting section H by the smoke P that has entered the device using the Th detection section Q. However, this photoelectric smoke detector has 1
If the amount of light emitted by the light emitting part H decreases due to environmental conditions such as deterioration or dust, the signal from the detection part will not reach the alarm level and no alarm will be issued even though smoke at the alarm level is flowing in. There are problems with environmental friendliness and life deterioration (deterioration of smoke detection function). Furthermore, if the amount of light emitted from the light emitting section H increases due to electrical conditions or the like, there is an inconvenience that an alarm may be issued even though the concentration of smoke has not reached the alarm level. Note that some devices are equipped with a light receiving section that determines whether or not the light emitting section H is emitting light, but this only issues an alarm when the output of the light emitting section falls below a certain level, and does not control the amount of light emitted. , the same problem as Shishuiki remains.

Accordingly, an object of the present invention is to provide a photoelectric smoke sensor that has excellent environmental resistance and prevents instability in operation due to deterioration of the smoke detection function.

An embodiment of this invention is shown in FIG. That is, this photoelectric smoke detector is for smoke entry space l.

A light emitting unit 2 that emits a predetermined amount of light is arranged within the space l, and the scattered light is arranged so that only scattered light 5 generated when smoke 4 enters the space 1 can be received in response to this light 3. A detection section 6 is arranged, a judgment section 7 sets an alarm level, and outputs a detection output when the alarm level is exceeded. The configuration up to this point is the same as that of a general photoelectric smoke detector. Further, a light emission amount detection section 8 is arranged to receive the light 3 of the light emitting section 2, and the light emission amount detection section 9 compares the output signal level of the detection section 8 with a reference level, and calculates the difference between the light emission amount and the reference level. A light emitting unit 20 that feeds back light to the control unit lO and emits light into the smoke entry space l.
The light emission amount I is controlled to be constant VC.

Because of this configuration, the life of the light emitting unit 1 and 2 may deteriorate,
Even if the amount of light emitted from the light emitting section 2 changes due to environmental and electrical conditions, it is controlled to always remain constant by the amount of light emitted light detecting section 8 and the amount of light emitting control section 1O, so the scattered light detecting section 6 is a cheap one. It can be operated as a computer and has excellent IT environment. This feature also reduces the number of times the sensor needs to be cleaned.

High n! for cases such as obtaining analog output of smoke density, multi-stage alarms, etc. The photoelectric smoke detector of the present invention has the following features: 0 or more, which enables highly accurate detection and makes it easy to take measures against malfunctions of the light emitting part, etc.

The amount of light emitted from the light emitting part? Equipped with a light emission detection unit and a control unit that control the amount of light emitted at a constant level, it has excellent environmental resistance, prevents instability such as life deterioration, reduces the number of cleaning and inspections, and achieves high accuracy of analog output. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional example, and FIG. 2 is a diagram of an embodiment of the present invention. l・Smoke entry space part, 2... Light emitting part, 3... Light, 4...
・Smoke, 5...Scattered light, 6...Scattered light detection section, 8...
Light emission amount detection section, 10... Light emission amount control section

Claims (1)

[Claims] A smoke entry space, a light emitting unit that emits light into the smoke entry space, 1! A scattered light detection section that receives scattered light due to smoke that has entered the smoke entry space; a light emission amount detection section that receives light from the light emitting section; A photoelectric smoke detector, comprising: a light emission amount control section that controls the light emitting section so that the amount of light emitted into the entrance space is constant.