JPH0562831U - Heat detection cable and heat detection sensor - Google Patents

Abstract

(57) [Summary] [Purpose] With a simple structure, it can be installed easily and can reliably detect abnormal high temperatures over long distances. [Operation / Structure] The spun optical fiber is first coated with a thermosetting resin, then dried in a drying oven and coated with a plastic material. The optical fiber is coated with a heat-shrinkable member to detect heat. Put the cable around the place where abnormal high temperature is detected. When an abnormally high temperature occurs at any place where the heat detection cable is stretched, the heat shrinkable member coated on the optical fiber causes heat shrinkage. Then, a large external force is applied to the optical fiber due to lateral pressure, and a slight bending (microbending) occurs in the optical fiber. This slight bending of the optical fiber increases the transmission loss of the optical fiber.
Therefore, the intensity of the optical signal emitted from the optical signal intensity measuring instrument connected to the other end of the optical fiber is lower than the intensity of the optical signal incident from the optical signal incident instrument connected to one end of the optical fiber. To do. An abnormal high temperature is detected by measuring the intensity of the optical signal emitted from this optical signal intensity measuring device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heat sensing wire, and more particularly to a heat sensing cable and a heat sensing sensor that are simple in construction, lightweight, easy to install, and capable of easily detecting abnormal high temperatures over long distances.

[0002]

[Prior Art]

 With the development of the unit construction method, the layout of each room in modern houses has been standardized to some extent, making design and construction easier. Moreover, in recent years, the number of rooms has increased with the spread of two-family homes where two parents and children live together, and the total floor area of the building has increased, and each room has become an independent floor plan. Although these modern houses use new building materials, not all noncombustible materials are used, but mainly wooden structures. However, unlike modern office buildings, these modern houses do not have sprinklers and do not have sufficient disaster prevention equipment.

An abnormal temperature rise at a specific location may be accompanied by a risk of alteration of surrounding objects or ignition of surrounding objects. If such an abnormal temperature rise occurs, rapid temperature rise may occur. In addition, it is necessary to detect changes in the situation and avoid these dangers, and at the same time, take rapid repair measures for abnormal locations. Once a fire occurs in a wooden house, the building often burns down if the fire cannot be extinguished during the initial extinguishing stage. Therefore, in recent years, in order to prevent the occurrence of fire due to an abnormal temperature rise, it is required to detect an abnormal temperature rise in a specific room or each room in advance.

Conventionally, in order to detect this abnormal temperature rise in advance, a heat detection line as shown in FIG. 4 (see Japanese Utility Model Laid-Open No. 61-9728) is often used. That is, in the conventional heat detection wire 100, a piano wire 110 is used as a conductor, and a plurality of wire cores (two wires in FIG. 3) in which an insulator 120 is covered on the piano wire 110 are twisted together, and the twisted wire A film 130 made of polyester resin is wound around the above as a press winding, and is formed by covering a sheath (not shown).

In the heat detecting wire 100, a predetermined voltage is applied in advance between the twisted wire cores, and when the surrounding temperature becomes a certain temperature or higher, the insulator 120 softens and the piano wire 110 is sprinkled. By action, the two cores push out the melted insulator 120, contact each other and short-circuit, and detect an abnormally high temperature.

The heat detection line 100 is provided around a place where a high temperature is detected to detect the temperature at that place. Therefore, in order to detect abnormal temperature rises in all parts of the room in advance, it is necessary to extend the heat detection line inside the room, and if it is set up inside the room, the length of the heat detection line becomes long. However, in the conventional heat detection wire using piano wire as the conductor, if the heat detection wire laid inside the room becomes long, the voltage drop of the voltage applied to the piano wire increases. However, there is a problem that the electric current necessary to detect the abnormal temperature cannot be secured, and the abnormal temperature may not be detected when the indoor temperature rises abnormally.

Therefore, in recent years, by utilizing the transmission loss of an optical fiber, it is possible to reliably detect an abnormal temperature when the temperature inside the room rises abnormally even if the heat detection line is extended in the room and becomes long. A heat sensing line 200, such as that shown in FIG. 5, is contemplated. That is, the heat detection wire 200 is formed by bonding both ends of a string-shaped heat-shrinkable member (or rod-shaped heat-shrinkable member) 210 having a predetermined length to the optical fiber 220 as shown in FIG. There is. In the heat detecting wire 200 as shown in FIG. 5, when the ambient temperature exceeds a certain temperature, the cord-like heat shrinkable member 210 causes heat shrinkage, and the optical fiber 220 is bent as shown in FIG. The optical fiber cable causes a slight bend (micro bending), which increases the transmission loss. Therefore, the abnormal high temperature is detected by measuring the intensity change of the optical signal due to the bending of the optical fiber 220 by the cord-like heat-shrinkable member 210.

[0008]

[Problems to be solved by the device]

 However, in the conventional heat detection line using an optical fiber, it is necessary to stretch it around the place where the high temperature is detected, and a string-like heat-shrinkable member is attached to each place where the high temperature is detected. For this reason, many string-shaped heat-shrinkable members must be attached to the optical fiber, and there is a problem that it cannot handle when the temperature detection line is extended over a wide range and the heat detection line is attached over a long distance. is doing.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to have a simple and lightweight structure, easy installation, and long distance. The present invention aims to provide a heat detection cable and a heat detection sensor capable of easily detecting an abnormally high temperature.

[0010]

[Means for Solving the Problems]

 In order to achieve the above object, the heat detecting cable of the present invention comprises an optical fiber coated with a heat shrinkable member.

In addition, in order to achieve the above-mentioned object, the heat-sensitive sensor of the present invention coats an optical fiber with a heat-shrinkable member whose shrinkage rate changes in response to temperature changes, and An optical signal injector for inputting an optical signal at one end is connected to an optical signal intensity measuring device for measuring the intensity of an optical signal emitted at the other end of the optical fiber.

Further, it is preferable that the optical signal intensity measuring device is configured to measure the increase amount of the transmission loss of the optical fiber.

[0013]

[Action]

 The spun optical fiber is first coated with a thermosetting resin, then dried in a drying oven, and the optical fiber formed by coating a plastic material is coated with a heat-shrinkable member to form a heat detection cable. A heat detection cable constructed by coating an optical fiber with a heat-shrinkable member whose shrinkage rate changes according to changes in temperature is laid all over the place where abnormal high temperatures are detected. When an abnormally high temperature occurs in any place where the heat detection cable is stretched, the heat shrinkable member coated on the optical fiber causes heat shrinkage. Then, a large external force due to lateral pressure is applied to the optical fiber, and a slight bending (microbending) occurs in the optical fiber. This slight bending of the optical fiber increases the transmission loss of the optical fiber. Therefore, the intensity of the optical signal emitted from the optical signal intensity measuring instrument connected to the other end of the optical fiber is higher than the intensity of the optical signal incident from the optical signal injector connected to one end of the optical fiber. descend. An abnormal high temperature is detected by measuring the intensity of the optical signal emitted from this optical signal intensity measuring device.

[0014]

【Example】

 Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of a heat detecting cable according to the present invention.

In the figure, 1 is a heat detection cable and 2 is an optical fiber. The optical fiber 2 is composed of a core having a high refractive index portion and a clad having a low refractive index portion, and has a concentric structure in which the clad surrounds the core. This optical fiber 2 usually uses a concentric platinum double crucible. A core is placed in the center crucible and a glass that serves as a clad is placed in the outer crucible and melted, and a drawing line is drawn from the nozzle aligned with the center axis. Simultaneously, the thermosetting resin is first coated and dried, and the primary coating resin is coated with a plastic material. As the optical fiber 2, it is possible to use a normal fiber such as a multimode fiber, a single mode (SM) fiber, a graded index (GI) fiber, a step index (SI) fiber.

Reference numeral 3 denotes a heat-shrinkable member, which is formed in a tube shape and covers the optical fiber 2. The heat-shrinkable member 3 is made of a heat-shrinkable synthetic resin. The heat shrinkage of a synthetic resin is a phenomenon in which when a polymer solid having a stretching history is heated, a rapid shrinkage occurs in a certain temperature range. The abrupt shrinkage of the synthetic resin that occurs when heated causes the internal state of the polymer solid, which was fixed in the stretched state at the temperature that causes thermal shrinkage, to It occurs because the composition state is unfrozen and tries to return to a state in which it is stable when the tension due to stretching is not working. This rapid shrinkage of the synthetic resin occurs near the glass transition temperature in the amorphous polymer and near the melting point in the crystalline polymer.

The amorphous polymer is also referred to as an amorphous polymer and is a polymer substance having no crystal structure, for example, a polymer such as polyvinyl acetate or polyethylene by radical polymerization. This non-crystalline polymer generally includes a polymer having an irregular structure (copolymer, branched polymer, etc.) or a polymer having bulky side chains and not having a regular structure.

The crystalline polymer is a polymer substance such as polyethylene, nylon, etc. which has a clear crystal structure by X-ray diffraction. Since this polymer compound has a long chain, it does not crystallize 100%. The crystallinity (ratio of crystallized molecules) changes depending on the crystallization conditions, heat treatment, etc. There are various crystalline polymers ranging from poorly polymerized polymers to linear polyethylene having a crystallinity of 80 to 90%.

Reference numeral 4 denotes a gap, which is formed by coating the heat shrinkable member 3 so as not to tighten the optical fiber 2.

FIG. 2 shows an embodiment of the heat detecting sensor according to the present invention.

In the figure, 10 is an O-TDR (Optical Time Domein Reflect Meter), in which an optical signal incident from one end of an optical fiber is reflected by a minute bend (micro bending) of the optical fiber, and accompanying this reflection. It is a measuring instrument (time domain optical pulse reflectometer) that displays the increase of transmission loss of optical signal on CRT in the time domain. The heat detection sensor is constructed by connecting the heat detection cable 1 to the O-TDR 10. The heat detection cable 1 connected to the O-TDR 10 is installed in a building or the like.

Next, the operation of this embodiment will be described. Now, when a fire occurs in a building or the like in which the heat detection cable 1 is laid and the temperature around the heat detection cable 1 rises, the heat generated by the fire causes the heat shrinking member 3 to cover the optical fiber 2 of the heat detection cable 1. Causes contraction. When the heat-shrinkable member 3 contracts, the heat-shrinkable member 3 fills the gap 4 and applies a lateral pressure to the optical fiber 2. When an external force with a large lateral pressure is applied to the optical fiber 2 by the heat shrink member 3, the optical fiber 2 is slightly bent (microbending). Due to this minute bending (micro bending), the transmission loss increases in the optical fiber 2. That is, the transmission loss of the optical fiber 2 rapidly increases when the heat-shrinkable member 3 contracts due to the heat of a fire.

Therefore, an optical signal is made incident from one end of the optical fiber 2 by a light generator (not shown), propagates in the optical fiber 2 and is emitted from the other end of the optical fiber 2. By measuring the intensity of the fire, it is possible to obtain measurement data on the temperature of the heat generated by the fire. At this time, as shown in FIG. 2, if the measurement is performed by the O-TDR 10 at one end of the optical fiber 2, the loss increase amount and its position can be immediately obtained by the CRT display as shown in FIG.

By changing the material of the heat-shrinkable member 3, the shrinkage rate of the heat-shrinkable member 3 with respect to heat is changed, and the detection temperature can be freely set.

[0025]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

In the heat detecting cable of the first aspect, since the optical fiber is formed by coating the heat shrinkable member, it is possible to reliably detect the abnormal high temperature with a simple structure.

In the heat-sensitive sensor of the second aspect, the optical fiber is coated with a heat-shrinkable member whose contraction rate changes in accordance with a change in temperature, and an optical signal is incident on one end of the optical fiber. Since it is configured by connecting an optical signal intensity measuring device that measures the intensity of the optical signal emitted to the other end of the optical fiber, it can be installed easily and easily over long distances. Moreover, the abnormally high temperature can be reliably detected.

In the heat-sensitive sensor according to the third aspect of the invention, the optical signal intensity measuring device detects by measuring the increase amount of the transmission loss of the optical fiber, so that the detected temperature can be freely set. ..

[Brief description of drawings]

FIG. 1 shows an embodiment of a heat detecting cable according to the present invention, and is an overall perspective view of a part of the heat detecting cable in section.

FIG. 2 shows an embodiment of a heat detecting sensor according to the present invention, and is a system configuration diagram using the heat detecting cable shown in FIG.

FIG. 3 is a diagram showing a measurement result by the heat detection sensor shown in FIG.

FIG. 4 is a cross-sectional view showing a conventional heat sensing wire.

FIG. 5 is an overall configuration diagram of a heat sensing line using a conventional optical fiber cable.

6 is a diagram showing a state in which an abnormal high temperature is detected by the heat sensing line of FIG.

[Explanation of symbols]

 1 ……………………………………………… Heat detection cable 2 ……………………………………………… Optical fiber 3 …………………… ……………………… Heat shrink member 4 ……………………………………………… Gap 10 ………………………………………… O- TDR

Claims (3)

[Scope of utility model registration request] 1. A heat detecting cable formed by coating an optical fiber with a heat-shrinkable member. 2. An optical signal injector for coating an optical fiber with a heat-shrinkable member whose contraction rate changes according to a change in temperature, and for inputting an optical signal to one end of the optical fiber. A heat-sensitive sensor that is configured by connecting an optical signal intensity measuring device that measures the intensity of the optical signal emitted to the end. 3. The heat detection sensor according to claim 2, wherein the optical signal intensity measuring device measures an increase amount of transmission loss of the optical fiber.