Linear temperature sensing fire detector with point-shaped temperature sensing element and alarm method thereof

Abstract

The invention relates to a linear temperature sensing fire detector with a point-shaped temperature sensing element and an alarm method thereof. The fire detector comprises a linear temperature sensing element, a converting box, a terminal resistor and a point-shaped temperature sensing element, wherein the point-shaped temperature sensing element is installed at the position of a cable joint andconnected with the converting box by two conductors. The linear temperature sensing fire detector and the alarm method adds the point-shaped temperature sensing element installed at the position of the cable joint on the linear temperature sensing fire detector in the prior art, and the electric parameters of the linear and point-shaped temperature sensing elements are alternately detected by theconverting box; once the cable joint position generates abnormal high temperature, the point-shaped temperature sensing element can transfer a sensing signal to the converting box immediately; accordingly, even if the temperature of the linear temperature sensing element does not reach an alarm threshold value, the converting box can also decide whether a fire alarm signal is transmitted or not according to the condition of the point-shaped temperature sensing element, and a detecting blind area can be eliminated, thereby improving the alarm reliability and the sensitivity of the fire detector.

Description

technical field [0001] The invention relates to a linear temperature-sensitive fire detector and an alarm method, in particular to a linear temperature-sensitive fire detector with a point-type temperature sensing element and an alarm method. Background technique [0002] The linear temperature sensing fire detector is a widely used fire detector, which mainly consists of a linear temperature sensing element with NTC characteristics, connected to one end of the linear temperature sensing element, and can monitor the temperature or temperature of the linear temperature sensing element in real time. Alarm electrical parameters (or sampled values) are detected, and a conversion box that sends out a fire alarm signal according to the temperature or the size of the alarmed electrical parameters (or sampled values) and the other end connected to the linear temperature sensing element activates the linear temperature sensing element. The terminal resistance of the open circuit moni...

AI Technical Summary

Problems solved by technology

But there is following problem in above-mentioned linear heat-sensitive fire detector of this prior art: figure 2 , image 3 As shown, one of the power cables A1 laid on the cable tray or the cable tray A2 may have a cable joint B that is prone to problems, and the cable joint B may overlap with a certain part of the linear temperature sensing element 1, It may also not coincide with the linear temperature sensing element 1 at all

In the former case, it is assumed that the normal alarm temperature of the line-type temperature-sensing fire detector is 85°C. If the abnormal high temperature occurs at the cable joint B, due to the limited contact area between the line-type temperature sensing element 1 and the cable joint B, the cable The heat on the joint B cannot be transferred to the linear temperature sensing element 1 quickly, so the conversion box 2 cannot detect the temperature of the linear temperature sensing element 1 or the change of the alarm electrical parameter, so that the linear temperature sensing fire detector is at 85°C The fire alarm cannot be reported normally, and the fire alarm can only be reported when the temperature at the cable joint B reaches 120°C, which may delay the alarm time, resulting in a fire accident caused by the cable joint B; In this case, since the line temperature sensing element 1 is not in contact with the cable joint B, the heat on the cable joint B cannot be transferred to the line temperature sensing element 1 in time, so the conversion box 2 cannot detect the line temperature The temperature of the sensing element 1 or the electrical parameters of the alarm change, so that the linear temperature-sensitive fire detector cannot normally alarm at 85°C, and even if the temperature at the cable joint B reaches 120°C, the fire alarm cannot be reported, so it may occur A fire accident caused by the explosion of the cable joint B, resulting in serious personal injury or equipment loss

Therefore, this prior art linear temperature-sensitive fire detector cannot detect the temperature at the cable joint B, that is, there is a detection blind zone, which will reduce the alarm reliability and sensitivity of the linear temperature-sensitive fire detector.

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