JPS6222411B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides an element that can simultaneously detect gas and smoke with one element by adding the smoke detection function of an optical smoke detector to a conventional gas detection element. It is something to do.

In recent years, with the spread of gas appliances and the airtightness of housing structures, gas explosion accidents have been occurring frequently and have become a major social problem. In response to this, efforts are being made to develop combustible gas detection elements that can easily detect combustible gases. Among these, research and development is particularly active in what is called a semiconductor method that uses metal oxides, and many proposals have been made from the material, structural, and application aspects including detection circuits.

On the other hand, along with gas accidents, fires are one of the major social problems. Particularly problematic in this fire is poisoning caused by the smoke generated in the early stages of the fire, that is, the toxic gas contained therein. Recently, many so-called new construction materials that use synthetic petroleum products have been used, which causes poisoning due to the smoke that smolders and contains toxic gases such as carbon monoxide. This can cause a major disaster. Therefore, smoke detectors have been developed and put into practical use that can quickly detect smoke generated in the early stages of a fire and issue an alarm.

In any case, gas accidents and fires are disasters that have become major social problems, especially in ordinary households. However, although detection elements and smoke detectors have been developed and put into practical use for these two important disasters, as mentioned above,
Currently, each is configured and used independently.

In view of this point, the present invention aims to provide a novel sensing element that can simultaneously detect gas and smoke by configuring these two elements with the simplest possible structure.

By the way, as general simple combustible gas detection elements, the following two methods have been devised. One is the so-called semiconductor method, which utilizes the fact that the resistance value of metal oxides heated to high temperatures changes when they come into contact with flammable gas, and the other is the so-called semiconductor method, which uses noble metal catalysts such as platinum that are heated to high temperatures. This is a so-called catalytic combustion type, which detects the temperature rise caused by the combustion of flammable gas on the surface as an increase in the resistance value of the metal. In either of these systems, a net whose main purpose is to provide an explosion-proof function is attached around the gas sensitive body. There are two types of materials for this net: mesh-shaped stainless steel and cap-shaped sintered metal.
They are used differently depending on their purpose. In particular, the latter type of cap, which uses sintered metal, has the property of allowing gas to pass through freely, but hardly allowing light to pass through.

On the other hand, there are two types of smoke detectors: the so-called ionization type, which takes advantage of the fact that the ionization current decreases due to the adsorption of smoke particles to ionized air, and the so-called ionization type, which takes advantage of the fact that the ionization current decreases when smoke particles are adsorbed to ionized air.
Optical types that utilize the Tyndall phenomenon are currently in use. In the latter method, a light emitting diode and a light receiving diode are arranged at appropriate positions in a detection chamber whose interior is painted black to prevent light scattering, and the light receiving diode detects the light emitted from the light emitting diode and scattered by smoke particles. It attempts to detect the presence of smoke.

The gas/smoke detection element according to the present invention incorporates the functions of the optical smoke detector described above into the sintered metal net of the gas detection element by using optical fibers. It has been combined to achieve multi-functionality.

Specific examples of the present invention will be described below.

Using a commercially available semiconductor type combustible gas detection element whose explosion-proof cap is made of sintered metal, holes of 1.5 mm diameter are first drilled in the sintered metal caps 3 at positions located at right angles to each other. Also, in the same commercially available optical smoke detector, the light emitting part 1 and the light receiving part 2
As shown in the figure, optical fibers 4 and 4' are connected from the light emitting section 1 and the light receiving section 2 to the small holes of the sintered metal cap 3, respectively. That is, the light emitted from the light emitting section 1 is guided into the cap 3 of the combustible gas detection element through the optical fiber 4. As mentioned above, the cap 3 made of sintered metal allows gas to pass through freely, but almost no light passes through it, so the interior of the cap is almost completely dark. Therefore,
If smoke enters this cap 3, the light emitting part 1
The light guided from the light emitting element hits the smoke particles and is scattered, producing scattered light inside the cap 3. This scattered light is guided to a light receiving element through an optical fiber 4' coupled to the light receiving section 2, and the presence of smoke can be detected. 5 is a gas sensitive body, and 6 is a heating heater.

In this way, by providing a smoke detection function with a new configuration within the conventional combustible gas detection element,
A multifunctional disaster prevention sensor can be realized with a very simple structure and configuration. Furthermore, considering that in the combustible gas detection element, the heater 6 that heats the gas sensitive body 5 also functions as a heat source for causing air convection within or around the element, It also has the effect of forcing smoke present around the element to flow into the element. Therefore, the element according to the present invention not only realizes two functions of gas detection and smoke detection in one element, but also allows the heater 6 of the combustible gas detection element to detect air. This has the effect of promoting convection and allowing smoke to be detected more quickly.

In the above-mentioned embodiment, a semiconductor type was used as the combustible gas detection element, but the element according to the present invention is not particularly limited to the semiconductor type, and the cap also has air permeability. It goes without saying that the material is not limited to the above-mentioned material made of sintered metal as long as it has both a light shielding property and a light shielding property.

[Brief explanation of the drawing]

The figure is a perspective view of a gas/smoke detection element in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Light emitting part, 2... Light receiving part, 3... Sintered metal net, 4, 4'... Optical fiber, 5... Gas sensitive body, 6... Heater.

Claims (1)

[Claims] 1. A combustible gas detection element equipped with a gas sensitive body and a heater that heats the sensitive body and induces forced convection of air into the cap is provided in an explosion-proof cap, and a pair of gas sensitive elements are provided in the cap. By inserting an optical fiber and connecting one end to a light emitter and the other end to a light receiver, smoke flowing into the cap through forced convection by the heater can be optically detected. Gas and smoke detection element.