Implementing method for back photoelectric smoke induction investigator and its device

Abstract

The invention discloses a method for realizing a backward photoelectric smoke detector and its device. It is provided in a dark room composed of a shading cover and a base, and is provided with a place where the emitting light path of the light transmitter and the receiving light path of the light receiver intersect. The composed detection area is respectively covered with a transmitting light guide and a receiving light guide on the outside of the light transmitter and the light receiver. A cone-shaped emitting light path, the receiving light pipe makes the light path received by the light receiver present a cone-shaped receiving light path with the light receiver as a cone point. The invention has as large a detection area as possible and as little background light as possible, and also has the advantages of simple structure, low cost and convenient installation.

Description

technical field [0001] The present invention relates to a method for making a backward photoelectric smoke detector have as large a detection area as possible and as little background light as possible, and a photoelectric smoke detector that detects smoke concentration through the working principle of scattered (reflected) light . Background technique [0002] The photoelectric smoke detector uses the principle of scattering (reflection) of infrared light in smoke particles to realize smoke detection. It is generally composed of a dark room, a light transmitter, a light receiver, and related structures and circuits. [0003] Existing photoelectric smoke detectors can be divided into forward photoelectric smoke detectors and backward photoelectric smoke detectors from the perspective of the arrangement of light emitters and light receivers. The so-called backward photoelectric smoke detectors refer to The angle between the optical central axis of the light emitted by the op...

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Problems solved by technology

[0007] This structure is equipped with lenses at the front end of the transmitting tube and the front end of the receiving tube. Due to the effect of the lens, the transmitting light path and the receiving light path are both cylindrical, and the intersection of the two, that is, the section along the optical central axis of the detection area is a parallelogram. , which greatly limits the size of the detection area, and the smaller detection area makes it difficult to guarantee the azimuth consistency. When a larger detection area is to be obtained, it is necessary to increase the angle between the light emitter and the light receiver or Enlarging the size of the detector itself, increasing the included angle will lead to insensitivity to black smoke, and increasing the size of the detector will bring about a substantial increase in cost; in addition, lenses are installed at the front end of the optical transmitter and optical receiver , it is also prone to lens deformation, high installation difficulty, and high cost. At the same time, dust accumulation on the lens surface or fog accumulation caused by drastic changes in ambient temperature and humidity have a huge impact on the signal. On the one hand, short-term fog accumulation can easily lead to a large signal On the other hand, the accumulation of dust requires regular cleaning, and the installation and cleaning of the lens is extremely difficult, which seriously limits the practicality and long-term use of the detector

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