JPS62274227A - Abnormal local temperature detector - Google Patents

Abstract

PURPOSE:To surely detect the non-specific local abnormal temp. of a wide surface by conducting electrodes which face each other by an expandable base material infiltrating through the through-holes of an insulating layer by softening and melting. CONSTITUTION:This detector is formed by providing the heat sensitive expandable layer 1 consisting of semi-conductive or conductive plastic sheet of a polyolefinic homopolymer, etc. and the insulating layer 2 having the many through-holes 3 between metallic foil layers 4 which are the electrodes and if necessary, by forming an insulating protective layer 5 on the outermost layer. The heat sensitive expandable base material layer 1 of the long-sized sheet-like detector is thereby softened and melted by a temp. rise and is infiltrated into the through-holes 3 of the insulating layer 2, by which the electrodes 4 facing each other are conducted to each other and the non-specific local abnormal temp. of the wide surface is surely detected.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention is a novel method for detecting localized abnormal temperatures on the surface of a surface heating element or the floor of a building. The purpose is to prevent fires from occurring regarding sensitive objects.

[Conventional technology]

Conventional abnormal temperature detection technology involves laying one detection line in a meandering pattern between two opposing electrodes,
Some are equipped with a planar sensing element such as a plastic thermistor, and catch changes in resistance or capacitance of the sensing layer due to changes in ambient temperature through electrodes, and others are sensing wires with an insulator interposed between the two electrodes. There is a type of temperature hiase method that uses a meandering arrangement and detects an abnormality by melting the insulator and making the electrode conductive when an abnormal temperature rise occurs.

However, the former measures the resistance and capacitance over the entire length of the detection wire or the entire surface of the planar detector, and has the disadvantage that it cannot detect localized abnormal temperatures on the surface, and the latter is not reliable. The disadvantages are that it is not sufficient and that it is not possible to carry out detailed inspections across the board. Furthermore, a method of installing a ceramic thermistor in a necessary part has been used, but this method has the disadvantage that it can only be detected in a certain part.

[Problem that the invention seeks to solve]

Among the above-mentioned conventional abnormal temperature detection techniques, there has not been one that can reliably detect when a local abnormal temperature occurs in an unspecified portion over a wide range of a surface. The present invention has been made to solve this problem, and the detecting body according to the present invention is installed in close proximity to a surface heating element, and under a rug on a floor. The system detects local abnormal temperatures and attempts to stop a fire from occurring at the local burnout stage.

[Failure to solve the problem]

FIG. 1 is a cross-sectional view showing the structure of a local abnormal temperature detector according to the present invention. In the figure, 1 is a heat-sensitive expandable base material layer made of a semiconductive or conductive plastic sheet, which is a polyolefin homopolymer.

Based on copolymers, polyesters, plastics such as soft PvC, various elastomers, etc.1, metal powder,
It is a film or sheet-like product made by blending conductive powder such as graphite powder or carbon black, and further adding and mixing metal salts, metal oxides, metal hydrates, organic blowing agents, etc. This base material layer preferably has a volume resistivity of 103Ω・
α or less, and at a certain temperature, for example, 200° C. or higher, it exhibits a significant volumetric expansion of υ100 cm or more due to gases generated from the compounding agents.

2 is an insulating layer with a large number of through holes 3 layered on the base material layer 1, and is an insulating film, sheet, or coarse insulating film made of plastic, paper, or other material with a large number of fine holes drilled all over the surface. Non-woven films, sheets, coarse woven fabrics made of fibers, and films and sheets that have a large number of voids substantially in the thickness direction are applicable. 4 is a gold pA foil layer which serves as an electrode and is arranged to sandwich the heat-sensitive expandable base material layer 1 and the perforated insulating layer 2; metal foil may be used alone, but plastic film, non-woven paper, etc. It is also possible to use a base material laminated with metal foil, a metal layer with a thickness of several μm to several tens of μm formed by vacuum deposition, sputtering, plating, etc., or a material coated with conductive paint. It is.

Reference numeral 5 denotes an insulating protective layer formed as the outermost layer if necessary, and various plastics and elastomers are used.

[Action and effect of invention]

In the local abnormal temperature sensing body according to the present invention constructed as described above, the heat-sensitive expandable base layer 1 and the metal foil layer 4, which is one electrode, are insulated by the perforated insulation/1i21c during normal operation. . When a localized abnormal temperature rise is detected from the outside, the expandable base layer 1 in that area softens and melts, begins to expand in volume, and enters the through holes 3 of the insulating layer 2, and as this progresses, When the two electrodes 4, 4 finally come into contact with one of the insulated metal foil layers 4, they become electrically conductive through the expansion layer in that part as shown in the second figure. Therefore, by connecting the HV-wire taken out from these two electrodes 4, 4 to an alarm device such as a lamp or a buzzer to form a closed circuit, abnormal conditions can be detected immediately and an alarm can be issued.

As explained above, the detection body according to the present invention has the effect of being able to reliably detect abnormal temperatures occurring in unspecified local areas on a wide surface. In carrying out the process, a long film or sheet-like sensing body having a cross section as shown in the first diagram and an appropriate width is manufactured, cut to the required length, or laid in an appropriate number of strips. It can be used by adapting it to the area you want to detect.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the structure of the detector according to the present invention, with FIG. 1 showing the structure during normal operation, and FIG. 2 showing the structure during local abnormal temperature detection. 1... Heat-sensitive expandable base material layer, 2... Insulating layer, 3...
Through hole, 4... Electrode, 5... Insulating protective layer.

Claims (1)

[Claims] interposing the two metal foil layers in contact with each other,
With a heat-sensitive expandable base layer made of semi-conductive to conductive plastic sheet and an insulating layer with many holes,
A local abnormal temperature sensing element, characterized in that the two metal foil layers are electrically insulated and configured such that conduction occurs between the two metal foil layers through the through holes of the insulating layer by softening and melting of the expandable base layer when sensing abnormal heat.