【 Weak current College 】 line fiber thermal detectors in roof building applications---Power By 【 China power house network 】

Summary: analysis through actual test, using vegetal roof material combustion characteristics that line fiber thermal detectors can effectively accomplish on early detection of such buildings. Key words: fiber-optic line type heat detector; vegetal materials; fire judgment algorithm
Most used wooden structure of the history of the ancient ruins of ancient architecture and the use of the thatched roof, bark, veneer and other vegetal material. In the hot summer months, these buildings from the roof surface is more likely to fire. The building once there is a fire, flame, not only may cause the ancient ruins of ancient buildings, burnt, more likely to spread to the adjacent building. Traditional fire detectors, primarily for building internal fires early detection, from the roof surface fires for early detection of effects is not very obvious. This article in outdoor settings with vegetal material roof of the building model, on the roof surface set line fiber thermal detectors collecting data through a variety of material combustion test for adopting the line of fire judgment algorithm fibre heat detector detection performance testing proved that, through the roof surface set line fiber thermal detectors that can effectively accomplish the roof using vegetal material for ancient buildings, the ancient site of fire was early detection. L fire judgment algorithm flowchart fire judgment algorithm as shown in Figure 1. Style fiber optic temperature sensor detector settings on the roof of the inner surface of the outer surface and, as the ambient temperature changes, output analog values. The analog value through data processing to detect the temperature value, tn, tn and fixed temperature comparison section preset fixed temperature values, when compared to tsl is greater than the tsl fire alarm signal when issued. Tn Probe temperature values to a temperature difference at the input and the reference temperature detection part of the set value, the temperature difference compared to tc to Δ t. Reference temperature tc is part of the reference temperature correction in accordance with the following formula to each calculated fixed temperature values. Tc = tc ' + 0.16 (tn-tc) tn: this probe temperature tc: the reference temperature tc ': the next reference temperature value figure 1 fire judgment algorithm flowchart temperature detection section will calculate the difference in value Δ t enter into judgment, when fire Δ t is greater than the fire judgment section pre-set temperature value ts, issued a fire alarm signal. Figure 2 tn Probe temperature values and the reference temperature tc figure 2 when linear fibre heat detector probe temperature value tn skyrocketing, reference temperature tc and Δ temperature t curve over time. As shown in Figure 2, when the solid line represents the values of detection temperature tn according to certain trends straight up, according to the formula reference temperature value shown as a dashed line tc, that changes over time in accordance with the same tendency rising. Therefore, the difference in value Δ t over time become a fixed value.
Figure 3 is a detection rate of temperature rise of temperature tn as parameters, detect temperature tn and reference temperature TC temperature t time change Δ curve. As can be seen from the figure, the detection rate of temperature rise of temperature, temperature difference last tend to a higher value; detection rate of temperature rise of temperature, temperature difference last tend to a lower value. Figure 3 to detect temperature temperature rate is the difference in time-dependent parameters
2 data acquisition test the temperature in the summer of thatched roof is high, therefore through test collection thatched roof surface temperature data, analysis of the causes of false positives and characteristics, effectively distinguish real fires. As shown in Figure 4, the roof of the building model materials as thatch. Roof dimensions as long 240cm, width 35 cm 130em, thick, tilt angle 45 °, placement. Which part is the long grass 220cm, wide 110cm. As shown in Figure 5, linear fibre heat detector along the roof surface vertical 2 line setting, interval 50 cm. The roof surface at the same time set the thermocouple, Lux meter. Data acquisition time interval as 16s. Figure 4 building model test results as shown in Figure 6, linear fibre heat detector probe temperature rise with the Sun rose, when the weather is sunny and turn cloudy detects temperature drop. Test data to demonstrate linear fibre heat detector probe temperature and sunlight illumination between larger. Figure 5 fibre set figure 3 combustion test in the outer surface of the roof of the model respectively set line fiber thermal detectors, point infrared Flame detectors, point type UV flame detector, the inner surface of the roof, respectively set line fiber thermal detectors, smoke detectors-point. Linear fibre heat detector probe temperature value for tn, fixed temperature determine the value set is 60 tsl º C, the temperature difference judgment value ts is set to 7 º C, thatched roof materials are used, the cedar bark, veneer for combustion. 3.1 thatched roof combustion test condition set to the roof surface fire, wind blows above the roof. Test results are shown in figure?, linear fibre heat detector of the flame almost at the same time as the issue of fire alarm signals. Point-ultraviolet and infrared Flame detectors for thatched roof of the open fire the same alarm faster. Set in the roof of the inner surface of the point-smoke detector alarm time later, mainly due to the wind blowing from the roof top, smoke is very difficult to enter inside a building. 3.2 Cypress bark roof combustion test condition set to the roof surface fire, wind blowing directly to the roof so that smoke easily into the rooms. Test results as shown in Figure 8, line fiber thermal detectors in smoldering fire alarm signal phase issued. Cypress skin burns, smoldering fire features more obvious, when the smoke Chamber reaches a certain concentration, point-smoke detector issued fire alarm signal; the point type ultraviolet, infrared flame detector detection principle as its mainly on flame for detection, alarm time later. Figure 7 thatched roof combustion test Figure 8 cedar bark roof combustion 3.3 veneer roof combustion test conditions with the Cypress bark roof combustion. Test results as shown in Figure 9, line fiber thermal detectors in smoldering fire alarm signal phase issued. Thin wooden burning flame extremely tiny, almost in smoldering State and cypress bark roof combustion test similar to the point of the type smoke detector alarmTimes faster, point ultraviolet, infrared flame detector alarm time later. Figure 9 thin wooden roof combustion test results indicate that the line of fire judgment algorithm for optical fiber thermal detectors can effectively prevent false positives, and set the external surface of the roof of the point type infrared, UV flame detector and settings in the roof of the inner surface of the point-smoke detector of alarm time compare in fire detection with remarkable effectiveness.
4 yao?/DIV > by outdoor settings vegetal material roof construction model of fire tests that use this style fire judgment algorithm fibre heat detector application using vegetal material roof of ancient buildings and ancient ruins, can effectively accomplish the fire early detection, with strong practicability and effectiveness. References: [1] the mountain Bombo. optical fiber probes in the ancient buildings of Japan hochi machine co., Ltd £ ® technical papers, 1998 total issue 14.